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Hassan, Mohammed, Yongjie Miao, Joy Lincoln, and Marco Ricci. "Cost-Benefit Analysis of Robotic versus Nonrobotic Minimally Invasive Mitral Valve Surgery." Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery 10, no. 2 (March 2015): 90–95. http://dx.doi.org/10.1097/imi.0000000000000136.
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Objective To date, a direct comparison of minimally invasive mitral valve repair or replacement (mini-MVR) versus robotic MVR is lacking; therefore, the purpose of this study was to address this deficit and compare mini-MVR with robotic MVR from a cost-benefit perspective. Methods From a total of 759 literature citations, 21 studies were included for statistical comparisons of benefit outcomes, whereas 3 studies and our institutional experience were used to compare costs. Results The total cost per case exceeding that of conventional MVR is approximately $2063.90 for robotic MVR and $271 for mini-MVR. Mean 30-day mortality rates for mini-MVR and robotic MVR groups were 1.24% and 0.55%, respectively [106/8548 vs 6/1089; odds ratio (OR), 2.27; P = 0.052]. The conversion rate to conventional MVR was 0.77% in mini-MVR and 1.83% in robotic MVR (35/5092 vs 22/1046; OR, 0.32; P < 0.001). The rate of neurologic events was 1.32% in mini-MVR and 2.37% in robotic MVR (109/8257 vs 20/845; OR, 0.55; P = 0.02). Postoperative atrial fibrillation was seen in 11.42% of mini-MVR patients and in 19.67% of robotic MVR patients (371/3249 vs 203/1032; OR, 0.53, P < 0.001). Mean cardiopulmonary bypass time was longer in mini-MVR (137.4 vs 130.4 minutes), whereas cross-clamp time was shorter (82.2 vs 96.7 minutes). Conclusions Our comparative analysis provides insights into the clinical benefits versus variable costs relationship related to mini-MVR and robotic MVR.
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Hadi, Nizar Jawad, and Dhey Jawad Mohamed. "Study the Relation between Flow, Thermal and Mechanical Properties of Waste Polypropylene Filled Silica Nanoparticles." Key Engineering Materials 724 (December 2016): 28–38. http://dx.doi.org/10.4028/www.scientific.net/kem.724.28.
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This paper investigates the flow, thermal and mechanical properties of waste polypropylene (WPP) reinforced with silica (SiO2) nanoparticles (NPs). Recently the researches prove that the addition of NPs to the thermoplastic polymer produces significant change in its properties. SiO2 NPs of 0.001, 0.003, 0.006, 0.009, 0.012 and 0.015wt% were mixed with the WPP using twin screw extruder. The mixing process performed at 10 rpm and 190°C. The topography and particle size distribution of 0.001, 0.006 and 0.015 of SiO2 NPs concentrations samples are analyzed using atomic force microscopy (AFM). The crystallinity of nanocomposite was examined by X-ray diffraction. The melt flow rate (MFR) and melt volume rate (MVR) are tested due to SiO2 NPs concentration at standard condition using melt flow index (MFI) device. The shear viscosity and melt density are calculated using MFR and MVR values. Differential Scanning Calomitry (DSC) is used to show the effect of SiO2 NPs concentration on the thermal history of nanocomposite. Charpy impact strength and hardness are tested. The results show that the MFR and MVR increase with the NPs concentration increasing. The shear viscosity decreases with MFR and MVR increasing. The crystallinity level and the crystallinity temperature decreases with SiO2 NPs concentration increasing while impact and hardness increasing. Clear difference between solid and melt density is observed. There is a compatible between the thermal, flow and mechanical properties of different SiO2 nanocomposite samples.
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Loup, Guillaume, Sébastien George, Iza Marfisi, and Audrey Serna. "A Visual Programming Tool to Design Mixed and Virtual Reality Interactions." International Journal of Virtual Reality 18, no. 2 (January 1, 2018): 19–29. http://dx.doi.org/10.20870/ijvr.2018.18.2.2904.
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Mixed and Virtual Reality (MVR) devices are now more accessible. However, developing MVR applications is still complex for the majority of developers, because it requires specific expertise. For the past few years, several packaged solutions offered to assist developers who are non-MVR experts. These solutions rarely offer full freedom to create specific interactions adapted to the context. We therefore propose a new MVR tool named MIREDGE (MIxed and virtual REality Development tool for Game Engine). Its interface allows visual programming of MVR interactions. This solution aims at allowing developers to capitalize, re- use, share and associate interaction algorithms. It also takes into account software and hardware compatibility in order to compose new algorithms. The specific architecture of MIREDGE provides opportunities for MVR and non-MVR developers to collaborate to meet a common need: writing efficient MVR interaction algorithms. MIREDGE Editor was evaluated by 31 MVR and non-MVR developers. Results shows that MIREDGE Editor seems effective and efficient particularly for non-MVR developers.
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EL Adel, Mohamed, Mohammed Mahmoud Mostafa, Ahmed Ghoneim, and Mohamed Abdelkader Osman. "Clinical and echocardiographic evaluation of patients undergoing total leaflets preservation during mitral valve replacement; Does it make a difference?" Egyptian Cardiothoracic Surgeon 1, no. 2 (April 28, 2019): 32–39. http://dx.doi.org/10.35810/ects.v1i2.39.
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Background: The effect of anterior and posterior leaflet preservation on left ventricular function after mitral valve replacement is still the subject of ongoing research. The objective of this study is to analyze the early outcomes of total leaflets preservation compared to posterior and non-leaflet preservation during mitral valve surgery on cardiac function and dimensions measured by echocardiography and on the clinical outcomes.Methods: This prospective cohort study recruited 155 patients who had mitral valve replacement (MVR) from April 2016 to March 2018 at Assiut University Hospital. Patients were divided into three groups according to the technique of leaflets preservation; Group I (no leaflet preservation-N-MVR), Group II (total leaflet preservation- T-MVR) and Group III (posterior leaflet preservation-P-MVR). Patients who underwent redo mitral valve replacement (MVR) or those with endocarditis and had combined coronary artery bypass grafting with the MVR were excluded from the study.Results: There were nine early deaths (6%); eight patients were in Group I (N-MVR). Causes of mortality were massive intracranial hemorrhage (n= 2) and left ventricular failure (n=6). One patient died in Group III (P-MVR) from intracranial hemorrhage (1.3%). Hospital stay was significantly longer in N-MVR group compared to T-MVR and P-MVR (10.6±2.13 days in N-MVR group; p= 0.03 and 0.011 respectively). Postoperative low cardiac output occurred in all patients in N-MVR group. Left ventricular function (ejection fraction= 61.28±6.02%) and dimensions (end-diastolic diameter= 5.18±0.69 mm, end-systolic diameter= 3.58±0.78 mm) improved significantly in total leaflets preservation group.Conclusion: Leaflet preservation during mitral valve replacement was associated with improved clinical and echocardiographic outcomes. Non-leaflets preservation increased the risk of postoperative complications and length of hospital stay. Leaflet preservation is recommended as the standard approach during mitral valve replacement.
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Everaars, Henk, Guus A. de Waard, Stefan P. Schumacher, Frederik M. Zimmermann, Michiel J. Bom, Peter M. van de Ven, Pieter G. Raijmakers, et al. "Continuous thermodilution to assess absolute flow and microvascular resistance: validation in humans using [15O]H2O positron emission tomography." European Heart Journal 40, no. 28 (April 25, 2019): 2350–59. http://dx.doi.org/10.1093/eurheartj/ehz245.
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Abstract Aims Continuous thermodilution is a novel technique to quantify absolute coronary flow and microvascular resistance (MVR). Notably, intracoronary infusion of saline elicits maximal hyperaemia, obviating the need for adenosine. The primary aim of this study was to validate continuous thermodilution in humans by comparing invasive measurements to [15O]H2O positron emission tomography (PET). As a secondary goal, absolute flow and MVR were compared between invasive measurements obtained with and without adenosine. Methods and results Twenty-five patients underwent coronary computed tomography angiography (CCTA), [15O]H2O PET, and invasive assessment. Absolute coronary flow and MVR were measured in the left anterior descending and left circumflex artery using a dedicated infusion catheter and a temperature/pressure sensor-tipped guidewire. Invasive measurements were performed with and without adenosine. In order to compare invasive flow measurements with PET perfusion, subtending myocardial mass of the investigated vessels was derived from CCTA using the Voronoi algorithm. Invasive and non-invasive measurements of adenosine-induced hyperaemic flow and MVR showed strong correlation (r = 0.91; P < 0.001 for flow and r = 0.85; P < 0.001 for MVR) and good agreement [intraclass correlation coefficient (ICC) = 0.90; P < 0.001 for flow and ICC = 0.79; P < 0.001 for MVR]. Absolute flow and MVR also correlated well between measurements with and without adenosine (r = 0.97; P < 0.001 for flow and r = 0.98; P < 0.001 for MVR) and showed good agreement (ICC = 0.96; P < 0.001 for flow and ICC = 0.98; P < 0.001 for MVR). Conclusions Continuous thermodilution is an accurate method to measure absolute coronary flow and MVR, which is evidenced by strong agreement with [15O]H2O PET derived flow and resistance. Absolute flow and MVR correlate highly between invasive measurements obtained with and without adenosine, which confirms that intracoronary infusion of room temperature saline elicits steady-state maximal hyperaemia.
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Claus, Thomas, Martin Hartrumpf, Ralf Kuehnel, Christian Braun, Christian Butter, Johannes Albes, and Roya Ostovar. "MitraClip for High-Risk Patients with Significant Mitral Insufficiency: Shall We Unreservedly Recommend It?" Thoracic and Cardiovascular Surgeon 66, no. 07 (September 18, 2017): 537–44. http://dx.doi.org/10.1055/s-0037-1606329.
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Background MitraClip (Abbott Inc.) is propagated as a palliative option for high-risk patients with mitral insufficiency considered not qualifying for surgical repair. A proportion of patients requires consecutive surgery because of technical failure or inappropriate clinical improvement. Furthermore, surgical reconstruction is impossible in almost all patients after MitraClip implantation. Consequently, these patients receive replacement although primary repair may have been possible. The outcome of those patients compared with patients receiving primary mitral valve replacement (MVR) or mitral valve repair (MVP) was analyzed. Methods A total of 23 patients were retrospectively analyzed after MVR following MitraClip. Overall, 46 patients with corresponding demographic data and risk profile receiving primary MVR (23 patients) or MVP (23 patients) were retrieved for matched pair analysis. Results Mean age was 70 years in all groups, log European system for cardiac operative risk evaluation (EuroSCORE) was 22.47% ± 16.30 in MVR after MitraClip (MC), 22.34% ± 16.23 in MVP, and 22.33% ± 16.14 in MVR group. Preoperative left ventricular ejection fraction (LVEF) was 44%, and postoperative LVEF was 48% in all groups. The 30-day mortality was 21.7% in the MitraClip group whereas it was 4.3% in the MVR and 13.0% in the MVP group. The 1-year survival was 56.5% in the MitraClip group while it was 95.6% in the MVR group and 82.6% in the MVP group (Wilcoxon test: p = 0.007; chi-square test: p = 0.001 MitraClip vs. MVR; p = 0.054 MitraClip vs. MVP). Conclusions Patients requiring surgical MVR after the previous MitraClip fared worse than matched cohorts receiving primary MVR or MVP. Indication for MitraClip should, therefore, be made very cautiously given the excellent results gained with primary surgery.
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Chen, Lin, Baicheng Chen, Jia Hao, Xuefeng Wang, Ruiyan Ma, Wei Cheng, Chuan Qin, and Yingbin Xiao. "Complete Preservation of the Mitral Valve Apparatus during Mitral Valve Replacement for Rheumatic Mitral Regurgitation in Patients with an Enlarged Left Ventricular Chamber." Heart Surgery Forum 16, no. 3 (June 26, 2013): 137. http://dx.doi.org/10.1532/hsf98.20121128.
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<p><b>Background and Aims:</b> The merits of retaining the subvalvular apparatus during mitral valve replacement (MVR) for chronic mitral regurgitation have been demonstrated in clinical investigations. This study was to investigate the feasibility of total preservation of the leaflet and subvalvular apparatus at the native anatomic position during MVR in a rheumatic population with enlarged left ventricular chamber.</p><p><b>Material and Methods:</b> The techniques of valvular apparatus preservation used during MVR with or without aortic valve replacement were investigated in 128 patients with an enlarged left ventricular chamber suffering from rheumatic mitral regurgitation between October 2003 and December 2007. Seventy patients had the anterior leaflet and subvalvular apparatus excised but the posterior leaflet and subvlvular apparatus preserved during the mitral valve replacement (P-MVR group), and 58 patients had the anterior and posterior mitral leaflets and the subvalvalur apparatus completely preserved at the native anatomical position during the mitral valve replacement (C-MVR group). Echocardiography was performed preoperatively, at discharge, and after 3 months, 1 year, and 3 years to determine the left ventricular dimensions and function.</p><p><b>Results:</b> There were 2 cases (3.4%) of early death in the C-MVR group, and there were 4 cases (5.7%) of early death in the P-MVR group. There were 3 cases of late death 1 year after surgery, of which 1 case in the C-MVR group was caused by congestive heart failure and the other 2 cases in the P-MVR group were due to sudden death. Both groups exhibited significant improvement (<i>P <</i> .05) in left ventricular function instantly and late postoperatively. The reduction of the left ventricular end-diastolic diameter was more significant in the C-MVR group as compared to the P-MVR group (<i>P <</i> .05). A statistically significant increase in fractional shortening (FS) occurred in the C-MVR group compared to the P-MVR group.</p><p><b>Conclusion:</b> This study shows that complete mitral leaflet preservation at the native anatomical position during MVR is feasible in rheumatic patients with an enlarged left ventricular chamber and confers significant short-term and long-term advantages by preserving left ventricular function and geometry. Therefore, it is a safe, simple, and effective surgical technique and should be individualized during clinical use.</p>
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Han, Chungyong, Rohit Singh, Seon-Hee Kim, Beom K. Choi, and Byoung S. Kwon. "Suppression of EBV-induced LCLs using CAR T cells redirected against HLA-DR." Journal of Clinical Oncology 35, no. 7_suppl (March 1, 2017): 146. http://dx.doi.org/10.1200/jco.2017.35.7_suppl.146.
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146 Background: Recent studies demonstrated a therapeutic potential of T cells with chimeric antigen receptor (CAR) targeting CD19 in refractory B cell malignancies. However, CD19-CAR T cells frequently caused on-target off-tumor side effect, i.e. B cell aplasia, and led to the recurrence of CD19-negative leukemic cells. Alternative target antigen for B cell malignancies has to be excavated. Methods: We developed antibody clone, MVR, which specifically bound to HLA-DR that is highly expressed on malignant B cells. In particular, MVR recognized polymorphic region of HLA-DR, and indicated different binding affinity against various HLA-DR alleles. Based on MVR binding strength, PBMCs from high binder (MVRHigh) and low binder (MVRLow) were tested to generate MVR-CAR T cells. To evaluate the anti-tumor efficacy on B cell malignancies, MVR-CAR T cells were assessed for immune responses against Epstein-Barr virus (EBV)-induced lymphoblastoid cell line (LCL) in vitro and in vivo. Results: Final yield of MVR-CAR T cells generated from MVRHigh PBMCs was 10-fold lower than that of CD19-CAR T cells, presumably caused by "fratricide" among HLA-DR-upregulated MVR-CAR T cells. In contrast, fratricidal effect was ameliorated in MVR-CAR T cells generated from MVRLow PBMCs indicating that the interaction between MVR-CAR and MVRLow-HLA-DR was weak enough to achieve tolerance to fratricide. Of note, in spite of such low binding, MVRLow-LCLs were killed efficiently by the CAR T cells. Further quantitative analysis revealed that HLA-DR was far more upregulated on LCLs compared with normal T and B cells which did not undergo EBV-transformation. In accordance with this observation, MVR-CAR T cells successfully induced LCL-specific cytotoxicity without causing normal B cell damage in vitro and efficiently suppressed the outgrowth of metastasized tumors in LCL-xenografted immune-deficient mice. Conclusions: MVR-CAR T cells redirected against HLA-DR for B cell malignancies were evaluated for the cytotoxic efficacy in vitro and in vivo. Considering the alleviated on-target off-tumor side effect and the feasibility of targeting HLA-DR for CD19-deficient malignant B cells, MVR-CAR T cells can be an alternative option for B cell malignancies.
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Ott, Robert, Sebastian Kaule, Swen Großmann, Michael Stiehm, Klaus-Peter Schmitz, Stefan Siewert, Alper Ö. Öner, Hüseyin Ince, and Niels Grabow. "Transcatheter mitral valve repair devices - in vitro studies on the influence of device-width on mitral regurgitation." Current Directions in Biomedical Engineering 6, no. 3 (September 1, 2020): 217–20. http://dx.doi.org/10.1515/cdbme-2020-3055.
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AbstractMitral regurgitation (MR) is the most prevalent valvulopathy in the USA and the second most prevalent valvulopathy in Europe. Despite excellent clinical results of surgical mitral valve repair (SMVR), transcatheter-based mitral valve repair (MVR) procedures emerged as a feasible treatment option for surgically inoperable or high-risk patients suffering from clinically relevant MR. The current study investigates the impact of device-induced coaptationwidth on the hydrodynamic performance of insufficient mitral valves (MV) during left ventricular (LV) systole. A non-calcified, pathological MV model (MVM) featuring a D-shaped MV annulus with an area of 7.6 cm2 and a flail gap in the A2-P2 region was employed in an experimental setup. Pressure gradient-volumetric flow rate (Δp-Q) relations were investigated for steady-state backward flow with transvalvular pressure gradients ranging from (0.75 ≤ Δp ≤ 177.36) mmHg. Glycerol-water mixture (36 % (v/v) glycerol in water) at 37 °C with a density of (1 098.2 ± 1.3) kg·m-3 and a dynamic viscosity of 3.5 mPa∙s was used as circulatory fluid. In order to determine the impact of the width of transcatheter MVR devices during LV-systole Δp-Q relations were investigated for three MVM-configurations: (i) MVM without MVR device, (ii) MVM with one MVR device and (iii) MVM with two MVR devices implanted in the A2-P2 region. The MVR devices were manufactured from steel sheets with a thickness of 0.2 mm and feature arm lengths of 9.0 mm and a width of 5.0 mm. The conducted investigations show that the implantation of MVR devices in the A2-P2 region prevents the manifestation of an A2-P2 flail gap and thereby effectively reduces the retrograde blood flow during the LV-systole by 13 % with one MVR device and 27 % with two MVR devices implanted. Thus, the application of two MVR devices with a combined device-induced width of 10 mm results in a better MR reduction than the implantation of one MVR device with a device-induced width of 5 mm.
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Sjøberg, Kim A., Jens J. Holst, Stephen Rattigan, Erik A. Richter, and Bente Kiens. "GLP-1 increases microvascular recruitment but not glucose uptake in human and rat skeletal muscle." American Journal of Physiology-Endocrinology and Metabolism 306, no. 4 (February 15, 2014): E355—E362. http://dx.doi.org/10.1152/ajpendo.00283.2013.
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The insulinotropic gut hormone glucagon-like peptide-1 (GLP-1) has been proposed to have effects on vascular function and glucose disposal. However, whether GLP-1 is able to increase microvascular recruitment (MVR) in humans has not been investigated. GLP-1 was infused in the femoral artery in overnight-fasted, healthy young men. Microvascular recruitment was measured with real-time contrast-enhanced ultrasound and leg glucose uptake by the leg balance technique with and without inhibition of the insulinotropic response of GLP-1 by coinfusion of octreotide. As a positive control, MVR and leg glucose uptake were measured during a hyperinsulinemic-euglycemic clamp. Infusion of GLP-1 caused a rapid increase ( P < 0.05) of 20 ± 12% (mean ± SE) in MVR in the vastus lateralis muscle of the infused leg after 5 min, and MVR further increased to 60 ± 8% above preinfusion levels by 60 min infusion. The effect was slightly slower but similar in magnitude in the noninfused contralateral leg, in which GLP-1 concentration was within the physiological range. Octreotide infusion did not prevent the GLP-1-induced increase in MVR. GLP-1 infusion did not increase leg glucose uptake with or without octreotide coinfusion. GLP-1 infusion in rats increased MVR by 28% ( P < 0.05) but did not increase muscle glucose uptake. During the hyperinsulinemic clamp, MVR increased ∼40%, and leg glucose uptake increased 35-fold. It is concluded that GLP-1 in physiological concentrations causes a rapid insulin-independent increase in muscle MVR but does not affect muscle glucose uptake.
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El Gabry, Mohamed, Zaki Haidari, Fanar Mourad, Janine Nowak, Konstantinos Tsagakis, Matthias Thielmann, Daniel Wendt, Heinz Jakob, and Sharaf-Eldin Shehada. "Outcomes of mitral valve repair in acute native mitral valve infective endocarditis." Interactive CardioVascular and Thoracic Surgery 29, no. 6 (August 1, 2019): 823–29. http://dx.doi.org/10.1093/icvts/ivz187.
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AbstractOBJECTIVESMitral valve repair (MVR) is considered the treatment of choice for mitral valve (MV) regurgitation. However, MVR in acute native MV infective endocarditis is technically challenging and not commonly performed. Our goal was to report our outcomes of MVR in acute native MV infective endocarditis.METHODSBetween January 2016 and December 2017, 35 patients presenting with acute native MV infective endocarditis underwent MVR. Primary end points were successful MVR and freedom from recurrent endocarditis. Secondary end point was the postoperative incidence of major adverse events.RESULTSThe mean age was 58 ± 13 years (74% men) and the median logistic EuroSCORE was 17.1%. Twenty patients underwent isolated MVR; the other 15 patients underwent concomitant procedures. MVR was performed with removal of the vegetation (vegectomy), limited resection of the infected tissue, direct closure of the defect, besides annuloplasty in all patients. Mean intensive care and hospital stays were 5 and 17 days, respectively. All-cause mortality was 11% (4/35) at 30 days and a total of 23% (8/35) within a follow-up period of 10 ± 7.7 months. Endocarditis recurred in 2 patients 15 and 8 months after surgery, respectively. Both underwent successful MV re-repair. Follow-up echocardiography indicated none-to-trace, mild or moderate regurgitation in 15, 10 and 2 patients, respectively.CONCLUSIONSAlthough MVR in acute native MV infective endocarditis is a complex procedure, it offers a treatment option for such patients with acceptable short-term results. Limited resection in addition to annuloplasty is our preferred method of repair. Nevertheless, long-term results in a larger cohort are still mandatory.
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Jiang, ShengLi, ChangQing Gao, BoJun Li, ChongLei Ren, Yao Wang, Tao Zhang, ChangSong Xiao, Yang Wu, TingTing Cheng, and Lin Zhang. "Congenital Mitral Valve Regurgitation in Adult Patients." Heart Surgery Forum 14, no. 2 (April 26, 2011): 114. http://dx.doi.org/10.1532/hsf98.20101097.
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Objective: Congenital mitral valve regurgitation (MVR) is a rare disease found in adults. We report on our 5-year surgical experience with congenital MVR in adults.Methods: We reviewed the data for 48 consecutive patients (26 men), aged >18 years (median, 42 years; range, 18-78 years) who underwent operations for severe congenital MVR between June 2005 and May 2010. Patients with atrioventricular septal defect were excluded.Results: Congenital MVR was preoperatively diagnosed in 28 cases (58%). The lesions consisted of annular dilation (100%), valvular cleft (58%), prolapsed leaflet (40%), papillary muscle abnormality (5%), commissure fusion (2%), and leaflet deficiency (2%). Mitral valve repair was performed in 42 cases (88%) by means of Carpentier techniques. The other 6 patients underwent mitral valve replacement; one of these patients died of ventricular fibrillation 2 days after surgery. There were no other hospital deaths or late mortality. At the last follow-up (median, 38 months; range, 2-50 months), all 47 patients were in New York Heart Association functional class I or II. Echocardiography evaluations for the 42 patients who underwent the repairs revealed that 32 (76%) of the patients had no or trivial MVR and 10 patients (24%) had mild MVR. No patient underwent reoperation.Conclusion: Congenital MVR is rare and often misdiagnosed in adults. Mitral valve repair is feasible in the majority of patients, with excellent immediate and medium-term results.
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Mater, Kathryn, Julian Ayer, Ian Nicholson, David Winlaw, Richard Chard, and Yishay Orr. "Patient-Specific Approach to Mitral Valve Replacement in Infants Weighing 10 kilograms or less." World Journal for Pediatric and Congenital Heart Surgery 10, no. 3 (May 2019): 304–12. http://dx.doi.org/10.1177/2150135119837200.
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Background: Mitral valve replacement (MVR) is the only option for infants with severe mitral valve disease that is not reparable; however, previously reported outcomes are not always favorable. Our institution has followed a tailored approach to sizing and positioning of mechanical valve prostheses in infants requiring MVR in order to obtain optimal outcomes. Methods: Outcomes for 22 infants ≤10 kg who have undergone MVR in Sydney, Australia, from 1998 to 2016, were analyzed. Patients were at a mean age of 6.8 ± 4.1 months (range: 0.8-13.2 months) and a mean weight of 5.4 ± 1.8 kg at the time of MVR. Most patients (81.8%) had undergone at least one previous cardiac surgical procedure prior to MVR, and 36.4% had undergone two previous procedures. Several surgical techniques were used to implant mechanical bileaflet prostheses. Results: All patients received bileaflet mechanical prostheses, with 12 receiving mitral prostheses and 10 receiving inverted aortic prostheses. Surgical technique varied between patients with valves implanted intra-annularly (n = 6), supra-annularly (n = 11), or supra-annularly with a tilt (n = 5). After a mean follow-up period of 6.2 ± 4.4 years, the survival rate was 100%. Six (27.3%) patients underwent redo MVR a mean of 102.2 ± 10.7 months after initial MVR. Four (18.2%) patients required surgical reintervention for development of left ventricular outflow tract obstruction and three (13.6%) patients required permanent pacemaker placement during long-term follow-up. Conclusions: The tailored surgical strategy utilized for MVR in infants at our institution has resulted in reliable valve function and excellent survival. Although redo is inevitable due to somatic growth, the bileaflet mechanical prostheses used displayed appropriate durability.
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Li, Feng Jiao, Ji Zhao Liang, Bo Zhu, and Ke Jian Wang. "Flow and Die-Swell Behavior in Extrusion of PLLA Melts." Advanced Materials Research 1051 (October 2014): 156–61. http://dx.doi.org/10.4028/www.scientific.net/amr.1051.156.
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The rheological properties of two kinds of poly (L-lactic acid) melts (AI-1001 and 4032D) have been investigated using a melt flow indexer within the temperature range from 170 to 190 and load varying from 2.16 to 12.5 kg. It was found that the melt volume flow rate (MVR) and extrudate swell ratios (B) increased non-linearly with increasing load when the temperature was constant; the MVR increased while the B decreased with a rise in temperature for both the AI-1001 and 4032D melts; the relationship between the MVR and temperature obeyed expression like as the Arrhenius equation when the load was fixed. Under the same test conditions, the values of the MVR and B of the AI-1001 melt were higher than those of the 4032D melt, and the sensitivity of the MVR and B to the load for the former is higher than those for the latter.
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Polanco, Antonio R., Alex D’Angelo, Nicholas Shea, Sarah N. Yu, Yuting P. Chiang, Yuichi Shimada, Shepard D. Weiner, and Hiroo Takayama. "Impact of Septal Myectomy Volume on Mitral-Valve Replacement Rate in Hypertrophic Cardiomyopathy Patients." Cardiology 145, no. 3 (2020): 161–67. http://dx.doi.org/10.1159/000504215.
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Objective: Mitral regurgitation (MR) induced by systolic anterior motion in patients with hypertrophic cardiomyopathy (HCM) can frequently be abolished with a proficient septal myectomy (SM) without the need for mitral-valve replacement (MVR). ACC guidelines stress the importance of volume in improving outcomes after SM, but there is a lack of data measuring the impact of volume on the need for MVR during SM. This study was designed to assess the impact of institutional volume on MVR rates using national outcomes data. Methods: The Nationwide Inpatient Sample was queried from 1998 to 2011 and a total of 6,207 patients had a diagnosis of HCM and a procedure code for SM. Outcomes were compared between patients who underwent SM (group I) and SM and MVR (group II). Furthermore, patients were stratified into 3 groups based on the number of SMs at the performing institution: low experience (1–24 cumulative SMs), medium experience (25–49 SMs), and high experience (>50 SMs). These patients underwent multivariable analysis to determine the impact of institutional volume on MVR rate. Results: The total MVR rate was 26%. Perioperative outcomes were worse, i.e., there were higher rates of mortality, kidney injury, and urinary complications, in group II than in group I. Only 37.6% of patients were operated on at institutions meeting the guideline criteria of >50 cumulative SMs. When compared to patients in the high-experience group, patients in the low- (OR 2.7, 95% CI 2.3–3.2, p < 0.05) and medium-experience (OR 3.0, 95% CI 2.5–3.6, p < 0.05) groups were more likely to undergo MVR. Conclusion: Compared to reports from SM reference centers, national data suggest that MVR rates are quite high at SM. Patients undergoing SM at centers that do not meet the guideline standard have >2.5× the odds of undergoing MVR compared to those operated on at guideline-endorsed centers.
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Martin, Randolph P. "Commercial Use of MVR." Journal of the American College of Cardiology 67, no. 10 (March 2016): 1141–44. http://dx.doi.org/10.1016/j.jacc.2016.01.020.
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Alam, Md Jahangir, Md Ripter Hossain, S. M. Shahinul Islam, and Md Nurul Haque Mollah. "Regression based fast multi-trait genome-wide QTL analysis." Journal of Bioinformatics and Computational Biology 19, no. 01 (January 20, 2021): 2050044. http://dx.doi.org/10.1142/s0219720020500444.
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Multivariate simple interval mapping (SIM) is one of the most popular approaches for multiple quantitative trait locus (QTL) analysis. Both maximum likelihood (ML) and least squares (LS) multivariate regression (MVR) are widely used methods for multi-trait SIM. ML-based MVR (MVR-ML) is an expectation maximization (EM) algorithm based iterative and complex time-consuming approach. Although the LS-based MVR (MVR-LS) approach is not an iterative process, the calculation of likelihood ratio (LR) statistic in MVR-LS is also a time-consuming complex process. We have introduced a new approach (called FastMtQTL) for multi-trait QTL analysis based on the assumption of multivariate normal distribution of phenotypic observations. Our proposed method can identify almost the same QTL positions as those identified by the existing methods. Moreover, the proposed method takes comparatively less computation time because of the simplicity in the calculation of LR statistic by this method. In the proposed method, LR statistic is calculated only using the sample variance–covariance matrix of phenotypes and the conditional probability of QTL genotype given the marker genotypes. This improvement in computation time is advantageous when the numbers of phenotypes and individuals are larger, and the markers are very dense resulting in a QTL mapping with a bigger dataset.
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Buckley, N. M., M. Jarenwattananon, P. M. Gootman, and I. D. Frasier. "Autoregulatory escape from vasoconstriction of intestinal circulation in developing swine." American Journal of Physiology-Heart and Circulatory Physiology 252, no. 1 (January 1, 1987): H118—H124. http://dx.doi.org/10.1152/ajpheart.1987.252.1.h118.
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The capability of the developing intestinal circulation to maintain a vasoconstrictor response during postganglionic adrenergic nerve stimulation or norepinephrine infusion was examined in 34 swine aged 6 h to 2 mo anesthetized with pentobarbital sodium. Aortic and portal venous pressures, electrocardiogram (ECG), and blood flow (F) through the superior mesenteric artery were recorded, and intestinal vascular resistance (MVR) was calculated as mean pressure difference per mean F. Baroreceptor reflex inhibition by bilateral occlusion of the carotid arteries increased MVR, section of the splanchnic nerve and postganglionic fibers decreased MVR, and short-latency F decreases were obtained during mesenteric nerve stimulation (MNS). Latencies for the decreases in F shortened with age and with increasing MNS frequency (5–17 Hz) at any age. Prolonging MNS for 60 s at 10 or 12 Hz led to sustained high MVR in 6-h to 7-day-old animals; however, MVR decreased toward control before the end of the 60-s MNS period in animals 1 to 2 mo old. Intra-arterial infusion of norepinephrine (0.5 microgram X kg-1 X min-1) decreased F and increased MVR in all animals; but by 5 min of infusion, F was returning toward control level in all but the youngest. This demonstration that the least mature intestinal circulation was least capable of autoregulatory escape from vasoconstriction provides further evidence of its functional immaturity.
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Knapp, Sabine. "Quantification and Analysis of Risk Exposure in the Maritime Industry: Averted Incident Costs Due to Inspections and the Effect of SARS-Cov-2 (COVID-19)." Safety 7, no. 2 (June 2, 2021): 43. http://dx.doi.org/10.3390/safety7020043.
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Shipping provides essential services even during global pandemics such as SARS-CoV-2 (COVID-19). The present approach estimates the monetary value at risk (MVR) at the global and regional level for the world fleet and quantifies the amount of averted incident costs due to inspections. It also provides an indication of the effect of COVID-19 on both. This information can help maritime stakeholders to better understand their risk exposure and improve mitigation strategies. The analysis is based on the global fleet, using a comprehensive combination of data. The analysis confirms the importance to estimate all components at ship level, as safety qualities differ, and each vessel benefits differently from an inspection. Estimates of MVR were slightly higher than global insurance premiums with USD 13.7 to 17.8 billion. Over half of the MVR was due to other marine liabilities and hull and machinery, with cruise vessels leading to loss of life and injuries and oil tankers leading to pollution. The top 25 flags accounted for 87.9% of MVR with open registries in the lead. In terms of value of MVR per GRT, traditional flags, Non-IACS flags and owners located in low to upper middle-income countries, showed the highest values. Total MVR decreased by 4.18% due to the effects of the pandemic, but pollution risk exposure increased by 6% in 2020 as compared to 2019. Averted yearly incident costs were estimated to be 25% to 40% of global MVR, which highlights the importance of port state control inspection programs, but as inspection coverage decreased, this translated into a reduction of 6 to 11% of averted incident costs.
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Bhamidipati, Castigliano M., Gaurav S. Mehta, Muhammad F. Sarwar, Renganaden Sooppan, Karikehalli A. Dilip, and Charles J. Lutz. "Robot-Assisted Mitral Valve Repair a Single Institution Review." Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery 5, no. 4 (July 2010): 295–99. http://dx.doi.org/10.1097/imi.0b013e3181ed5103.
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Objective Mitral valve repair (MVR) is the definitive therapy for mitral myxomatous degeneration. Median sternotomy has been the traditional approach to repair until the advent of the da Vinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA). Minimally invasive surgical approaches for mitral repair have been slow to gain acceptance in cardiac surgery. We review the MVR results from our single-institution academic robotic program. Methods From August 2004 through April 2008, patients who underwent a robotic-assisted (RA) MVR were identified. RA technique included a 4-cm right minithoracotomy, femoral cardiopulmonary bypass with transthoracic aortic occlusion, and RA-MVR. Repair types were combinations of quadrangular/triangular leaflet resection, sliding plasty, chordal transfer/replacement, and edge-to-edge approximation, with band annuloplasty in all cases. Postrepair echocardiography and morbidity follow-ups were completed in all patients. Our primary outcome was adequacy of repair, and secondary outcome was major complications. Results There were 43 patients (29 male and 14 female) who underwent RA-MVR for severe (4 +) mitral regurgitation during the 4-year review. Average operative time was 272.26 minutes. Only one patient had mild postoperative mitral regurgitation, whereas 20 had trace and 22 had no regurgitation after repair. Mean ventilator time was 32.1 hours, and length of stay was 5.7 days. One third of the patients (33%) received postoperative-packed red blood cell transfusions (average: 2.4 units per patient). Twenty-eight percent of patients developed atrial fibrillation after repair. Most of the patients (95.3%) were discharged home. There were no 30-day mortalities. Conclusions Based on our small single-institution experience, RA-MVR provides an effective treatment for severe mitral valve regurgitation. Although procedure durability is slowly being established, preliminary results are promising. Careful programmatic advances with an integrated team approach can facilitate acceptable postoperative outcomes and excellent MVR.
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Berzingi, Chalak, Vinay Badhwar, Fahad Alqahtani, Sami Aljohani, Zakeih Chaker, and Mohamad Alkhouli. "Contemporary outcomes of isolated bioprothestic mitral valve replacement for mitral regurgitation." Open Heart 5, no. 2 (July 2018): e000820. http://dx.doi.org/10.1136/openhrt-2018-000820.
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BackgroundEarly experience with transcatheter mitral valve replacement (TMVR) highlighted several investigational challenges related to this novel therapy. Conclusive randomised clinical trials in the field may, therefore, be years ahead. In the interim, contemporary outcomes of isolated surgical bioprosthetic mitral valve replacement (MVR) can be used as a benchmark for the emerging TMVR therapies.MethodsWe used the nationwide inpatient sample to examine recent trends and outcomes of surgical bioprosthetic MVR for mitral regurgitation (isolated and combined).Results21 007 patients who had bioprosthetic MVR between 2003 and 2014 were included. Of those, 30% had isolated MVR and 70% had concomitant cardiac surgical procedure(s). In patients who underwent isolated bioprothestic MVR, mean age was 68±13, and females were the majority (58.4%). Most of these procedures were performed at teaching institutions (71.3%) and during an elective admission (64%). In-hospital mortality improved during the study period (7.8% in 2003 to 4.7% in 2014, p trend=0.016). Postoperative morbidities were common; permanent pacemaker 11.7%, stroke 2.4%, new dialysis 4.9% and blood transfusion 41.6%. Mean length of stay was 13±12 days, and 27.2% of patients were discharged to an intermediate care of rehabilitation facility. Cost of hospitalisation was $62 443±50 997.ConclusionsIsolated bioprosthetic MVR for mitral regurgitation is performed infrequently but is associated with significant in-hospital morbidity and mortality and cost in contemporary practice. These data are useful as benchmarks for the evolving TMVR therapies.
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Shenoy, Aroon. "Material’s Volumetric-Flow Rate (MVR) as a Unification Parameter in Asphalt Rheology and Quality Control / Quality Assurance Tool for High Temperature Performance Grading." Applied Rheology 10, no. 6 (December 1, 2000): 288–306. http://dx.doi.org/10.1515/arh-2000-0019.
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Abstract Rheological data of unmodified and polymer-modified asphalts are conventionally obtained from dynamic mechanical characterization and expressed in terms of sets of curves showing the variation of viscoelastic properties with frequency. Using the conventional melt flow indexer, the material’s volumetric-flow rate MVR (in cm3 / 10 minutes) through a predefined die under conditions of constant temperature and stress when obtained for the same asphalts, shows a direct relationship with the dynamic data. The MVR value helps in unifying the sets of dynamic data curves of |G*|, G” and |G* |/sin δ versus frequency in the case of unmodified asphalts, polymer-modified asphalts and asphalt mastics. The unification technique has a sound theoretical basis and the unified curves have far-reaching implications. Since MVR is so simple to determine quite accurately on a relatively inexpensive, easy-to-use flow measurement device (FMD), this parameter can be generated on paving sites or at refineries, if needed, rather than in research laboratories as is the case with the fundamental rheological parameters. The MVR can then be used as an excellent indicator of the fundamental rheological parameters through the use of the unified curves. The MVR can be utilized to accurately determine the currently used high temperature performance grade specification of paving asphalt. On account of the simplicity in obtaining this specification value from the MVR, it may be routinely used for quality control / quality assurance purposes. It can also be used as a rapid product development / formulation tool.
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Saker, Michael, and Jordan Frith. "From hybrid space to dislocated space: Mobile virtual reality and a third stage of mobile media theory." New Media & Society 21, no. 1 (August 11, 2018): 214–28. http://dx.doi.org/10.1177/1461444818792407.
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Research in the field of mobile communication studies (MCS) has generally moved away from focusing on how mobile phones distract users from their physical environment to considering how the experience of space and place can be enhanced by locative smartphone applications. This article argues that trajectory may be complicated by the emergence of a new type of mobile technology: mobile virtual reality (MVR). While an increasing number of handsets are specifically developed with MVR in mind, there is little to no research that situates this phenomenon within the continuum of MCS. The intention of this paper is accordingly twofold. First, the article conceptualizes MVR as a connective tissue between the two sequential tropes of MCS: physical distraction and spatial enhancement. Second, the article introduces the concept of ‘dislocated space’ as a way of understanding the embodied space MVR might configure.
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Maeda, Shoji, Qianhui Qu, Michael J. Robertson, Georgios Skiniotis, and Brian K. Kobilka. "Structures of the M1 and M2 muscarinic acetylcholine receptor/G-protein complexes." Science 364, no. 6440 (May 9, 2019): 552–57. http://dx.doi.org/10.1126/science.aaw5188.
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Muscarinic acetylcholine receptors are G protein–coupled receptors that respond to acetylcholine and play important signaling roles in the nervous system. There are five muscarinic receptor subtypes (M1R to M5R), which, despite sharing a high degree of sequence identity in the transmembrane region, couple to different heterotrimeric GTP-binding proteins (G proteins) to transmit signals. M1R, M3R, and M5R couple to the Gq/11 family, whereas M2R and M4R couple to the Gi/o family. Here, we present and compare the cryo–electron microscopy structures of M1R in complex with G11 and M2R in complex with GoA. The M1R-G11 complex exhibits distinct features, including an extended transmembrane helix 5 and carboxyl-terminal receptor tail that interacts with G protein. Detailed analysis of these structures provides a framework for understanding the molecular determinants of G-protein coupling selectivity.
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Hwang, Ho-Young, Suk-Ho Sohn, and Myoung-jin Jang. "Impact of Prosthesis-Patient Mismatch on Survival after Mitral Valve Replacement: A Meta-analysis." Thoracic and Cardiovascular Surgeon 67, no. 07 (October 9, 2018): 538–45. http://dx.doi.org/10.1055/s-0038-1675195.
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Background Numerous studies have demonstrated a negative impact of prosthesis-patient mismatch (PPM) on long-term clinical outcomes after aortic valve replacement. However, the impact of PPM after mitral valve replacement (MVR) on clinical outcomes is still controversial. This study was conducted to evaluate the impact of PPM on early and long-term survival after MVR. Methods A literature search of five databases was performed. The primary and secondary outcomes were all-cause mortality and early mortality, respectively. Subgroup analyses were performed according to the risk of bias, patients' age, proportion of female patients, and proportion of patients with mechanical MVR. Results Eleven nonrandomized studies including 8,072 patients were included in this meta-analysis. The overall incidence of PPM was 58.0% (range: 10.4–85.9%). The odds ratio of early mortality in nine studies was not significantly different between the PPM and non-PPM patients (odds ratio: 1.35; 95% confidence interval [CI]: 0.98–1.86). A pooled analysis in 11 studies demonstrated that all-cause mortality after MVR was higher in the PPM than non-PPM patients (hazard ratio [HR]: 1.39; 95% CI: 1.09–1.77). This analysis revealed a moderate to high heterogeneity (I 2 = 69.4%). When pooled analyses were performed in two subgroups according to the proportion of patients with mechanical MVR, there were low heterogeneity in each group. No other subgroup analyses demonstrated a significant difference in the HR of all-cause mortality. Funnel plots and Egger's tests showed no visually and statistically significant publication bias. Conclusion The present meta-analysis indicates that PPM negatively affects long-term survival after MVR.
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Lafci, Gokhan, Kerim Cagli, Omer Faruk Cicek, Kemal Korkmaz, Osman Turak, Alper Uzun, Adnan Yalcinkaya, Adem Diken, Eren Gunertem, and Kumral Cagli. "Papillary Muscle Repositioning as a Subvalvular Apparatus Preservation Technique in Mitral Stenosis Patients with Normal Left Ventricular Systolic Function." Texas Heart Institute Journal 41, no. 1 (February 1, 2014): 33–39. http://dx.doi.org/10.14503/thij-13-3241.
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Subvalvular apparatus preservation is an important concept in mitral valve replacement (MVR) surgery that is performed to remedy mitral regurgitation. In this study, we sought to determine the effects of papillary muscle repositioning (PMR) on clinical outcomes and echocardiographic left ventricular function in rheumatic mitral stenosis patients who had normal left ventricular systolic function. We prospectively assigned 115 patients who were scheduled for MVR surgery with mechanical prosthesis to either PMR or MVR-only groups. Functional class and echocardiographic variables were evaluated at baseline and at early and late postoperative follow-up examinations. All values were compared between the 2 groups. The PMR group consisted of 48 patients and the MVR-only group of 67 patients. The 2 groups’ baseline characteristics and surgery-related factors (including perioperative mortality) were similar. During the 18-month follow-up, all echocardiographic variables showed a consistent improvement in the PMR group; the mean left ventricular ejection fraction deteriorated significantly in the MVR-only group. Comparison during follow-up of the magnitude of longitudinal changes revealed that decreases in left ventricular end-diastolic and end-systolic diameters and in left ventricular sphericity indices, and increases in left ventricular ejection fractions, were significantly higher in the PMR group than in the MVR-only group. This study suggests that, in patients with rheumatic mitral stenosis and preserved left ventricular systolic function, the addition of papillary muscle repositioning to valve replacement with a mechanical prosthesis improves left ventricular dimensions, ejection fraction, and sphericity index at the 18-month follow-up with no substantial undesirable effect on the surgery-related factors.
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Maier, Rebecca H., Adetayo S. Kasim, Joseph Zacharias, Luke Vale, Richard Graham, Antony Walker, Grzegorz Laskawski, et al. "Minimally invasive versus conventional sternotomy for Mitral valve repair: protocol for a multicentre randomised controlled trial (UK Mini Mitral)." BMJ Open 11, no. 4 (April 2021): e047676. http://dx.doi.org/10.1136/bmjopen-2020-047676.
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IntroductionNumbers of patients undergoing mitral valve repair (MVr) surgery for severe mitral regurgitation have grown and will continue to rise. MVr is routinely performed via median sternotomy; however, there is a move towards less invasive surgical approaches.There is debate within the clinical and National Health Service (NHS) commissioning community about widespread adoption of minimally invasive MVr surgery in the absence of robust research evidence; implementation requires investment in staff and infrastructure.The UK Mini Mitral trial will provide definitive evidence comparing patient, NHS and clinical outcomes in adult patients undergoing MVr surgery. It will establish the best surgical approach for MVr, setting a standard against which emerging percutaneous techniques can be measured. Findings will inform optimisation of cost-effective practice.Methods and analysisUK Mini Mitral is a multicentre, expertise based randomised controlled trial of minimally invasive thoracoscopically guided right minithoracotomy versus conventional sternotomy for MVr. The trial is taking place in NHS cardiothoracic centres in the UK with established minimally invasive mitral valve surgery programmes. In each centre, consenting and eligible patients are randomised to receive surgery performed by consultant surgeons who meet protocol-defined surgical expertise criteria. Patients are followed for 1 year, and consent to longer term follow-up.Primary outcome is physical functioning 12 weeks following surgery, measured by change in Short Form Health Survey (SF-36v2) physical functioning scale. Early and 1 year echo data will be reported by a core laboratory. Estimates of key clinical and health economic outcomes will be reported up to 5 years.The primary economic outcome is cost effectiveness, measured as incremental cost per quality-adjusted life year gained over 52 weeks following index surgery.Ethics and disseminationA favourable opinion was given by Wales REC 6 (16/WA/0156). Trial findings will be disseminated to patients, clinicians, commissioning groups and through peer reviewed publication.Trial registration numberISRCTN13930454.
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Pfannmueller, Bettina, Martin Misfeld, Piroze Davierwala, Stefan Weiss, and Michael Andrew Borger. "Concomitant Tricuspid Valve Repair during Minimally Invasive Mitral Valve Repair." Thoracic and Cardiovascular Surgeon 68, no. 06 (December 31, 2019): 486–91. http://dx.doi.org/10.1055/s-0039-1700506.
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Abstract Background Concomitant use of tricuspid valve (TV) surgery and minimally invasive mitral valve (MV) repair is debatable due to a prolonged time of surgery with presumably elevated operative risk. Herein, we examined cardiopulmonary bypass times and 30-day mortality in patients who underwent MV repair with and without concomitant TV surgery. Methods We retrospectively evaluated 3,962 patients with MV regurgitation who underwent minimally invasive MV repair without (n = 3,463; MVr group) and with (n = 499; MVr + TVr group) concomitant TV surgery between 1999 and 2014. Preoperative parameters between the groups were significantly different; therefore, propensity score matching was performed. Results Mean cardiopulmonary bypass time for all patients was 125.5 ± 55.8 minutes in MVr and 162.0 ± 58.0 minutes in MVr + TVr (p < 0.001). Overall 30-day mortality was significantly different between these groups (4.8 vs. 2.1%; p < 0.001); however, after adjustment, there was no significant difference (3.3 vs. 1.2%; p = 0.07). Backward logistic regression revealed that cardiopulmonary bypass time was not a significant predictor for early mortality within the MVr + TVr cohort. Conclusion Concomitant TV repair using prosthetic rings through a minimally invasive approach is safe and does not lead to elevated early mortality in our patient cohort. Therefore, prolonged cardiopulmonary bypass time should not be the sole reason to rule out MV repair with concomitant TV repair and to prefer the use of suture techniques, which saves only a few minutes compared with prosthetic ring implantation.
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Bernardelli, E. A., T. Souza, A. M. Maliska, Thierry Belmonte, and M. Mafra. "Plasma Etching of Stearic Acid in Ar and Ar-O2 DC Discharges." Materials Science Forum 660-661 (October 2010): 599–604. http://dx.doi.org/10.4028/www.scientific.net/msf.660-661.599.
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Stearic acid is treated in a DC Ar-O2 plasma created by a cathode-anode confined system. The influence of the most important process parameters (gas flow rate, sample temperature, output power and exposure time) on the acid modification is studied. The evaluation of the influence of these parameters on grafting and etching of stearic acid was done by measuring the mass variation rate (MVR). The results show that when charged and chemically active species increase in density, what is directly connected with plasma parameters, the MVR increases too. In all experimental conditions, a negative MVR was obtained, due to the etching of the sample. The etching rate decreases with processing time, probably because of the formation of a product which is more resistant to plasma etching.
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Kulyabin, Yuriy Yu, Ilya A. Soynov, Alexey V. Zubritskiy, Alexey V. Voitov, Nataliya R. Nichay, Yuriy N. Gorbatykh, Alexander V. Bogachev-Prokophiev, and Alexander M. Karaskov. "Does mitral valve repair matter in infants with ventricular septal defect combined with mitral regurgitation?" Vestnik of Experimental and Clinical Surgery 11, no. 2 (June 30, 2018): 85–92. http://dx.doi.org/10.18499/2070-478x-2018-11-2-85-92.
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OBJECTIVES: This study aimed to assess mitral valve function after repair of ventricular septal defect (VSD) combined with mitral regurgitation (MR) in the mid-term follow-up period, to evaluate the clinical utility of simultaneous mitral valve repair (MVR).
METHODS: From June 2005 to March 2014, 60 patients with VSD and MR underwent surgical treatment. After performing propensity score analysis (1:1) for the entire sample, 46 patients were selected and divided into 2 groups: those with VSD closure and MVR - 23 patients and those with VSD closure without mitral valve intervention - 23 patients. The follow-up period - 32 (28;40) months.
RESULTS: There was no postoperative mortality in either group. There was no significant difference in the duration of the postoperative period between groups. Mean cardiopulmonary bypass time and aortic cross-clamping time were significantly longer in the 'VSD + MVR' group (cardiopulmonary bypass, P=0.023; aortic cross-clamp, P< 0.001). There was no significant difference in regurgitation area (P=0.30) and MR grade (P= 0.76) between groups postoperatively. There was no significant difference in freedom from MR ≥ 2+ between groups (log-rank test, P= 0.28). The only significant risk factor for recurrent MR ≥ 2+ during the follow-up period was mild residual MR in the early postoperative period ( P=0.037).
CONCLUSIONS: In infants with VSD combined with MR, simultaneous MVR has no benefits simultaneous MVR provided no advantage over that of isolated VSD closure. We found that the presence of mild residual MR in the early postoperative period predisposes the development of MR ≥ 2+ in follow-up period.
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Noack, Thilo, Kathleen Wittgen, Philipp Kiefer, Fabian Emrich, Matthias Raschpichler, Sarah Eibel, David Holzhey, et al. "Acute Effect of Mitral Valve Repair on Mitral Valve Geometry." Thoracic and Cardiovascular Surgeon 67, no. 07 (August 16, 2018): 516–23. http://dx.doi.org/10.1055/s-0038-1667327.
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Background The aim of this study was to quantify acute mitral valve (MV) geometry dynamic changes throughout the cardiac cycle using three-dimensional transesophageal echocardiography (3D TEE) in patients undergoing surgical MV repair (MVR) with ring annuloplasty and optional neochord implantation. Methods Twenty-nine patients (63 ± 10 years) with severe primary mitral regurgitation underwent surgical MVR using ring annuloplasty with or without neochord implantation. We recorded 3D TEE data throughout the cardiac cycle before and after MVR. Dynamic changes (4D) in the MV annulus geometry and anatomical MV orifice area (AMVOA) were measured using a novel semiautomated software (Auto Valve, Siemens Healthcare). Results MVR significantly reduces the anteroposterior diameter by up to 38% at end-systole (36.8–22.7 mm; p < 0.001) and the lateromedial diameter by up to 31% (42.7–30.3 mm; p < 0.001). Moreover, the annular circumference was reduced by up to 31% at end-systole (129.6–87.6 mm, p < 0.001), and the annular area was significantly decreased by up to 52% (12.8–5.7 cm2; p < 0.001). Finally, the AMVOA experienced the largest change, decreasing from 1.1 to 0.2 cm2 during systole (at midsystole; p < 0.001) and from 4.1 to 3.2 cm2 (p < 0.001) during diastole. Conclusions MVR reduces the annular dimension and the AMVOA, contributing to mitral competency, but the use of annuloplasty rings reduces annular contractility after the procedure. Surgeons can use 4D imaging technology to assess MV function dynamically, detecting the acute morphological changes of the mitral annulus and leaflets before and after the procedure.
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Wadud, Md Armane, Syed Tanvir Ahmed, Shahnoor Aziz, Ibrahim Khalilullah, and CM Shaheen Kabir. "Effects of Controling of Post Operative Hypergycemia (Stress Induced Hyperglycemia) in Adult Non-Diabetic Patients Undergoing Mitral Valve Replacement Surgery Under Cardiopulmonary Bypass." Bangladesh Heart Journal 34, no. 1 (June 25, 2019): 44–51. http://dx.doi.org/10.3329/bhj.v34i1.41907.
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Objectives: The objective of this study was to see whether there is an association between high blood glucose levels after operation under CPB and post operative morbidity and mortality.
Methodology: This cohort study was carried out in the Department of Cardiac Surgery at National Institute of Cardiovascular DiseaseS (NICVD), Sher-e-Bangla Nagar, Dhaka from January, 2012 to December, 2013 for a period of twenty four (24) months. A total number of 110 patients who underwent MVR operation with CPB were enrolled in this study as per inclusion and exclusion criteria. Patients were divided into two groups according to their post operative blood glucose levels, recorded with in first 60 hrs after mitral valve replacement surgery under cardiopulmonay bypass. Patients having blood glucose level of less than 10.1 mmol/L (unexposed) and patients having blood lactate level of 10.1 mmol/L or more (exposed) were grouped. Post operative variables were observed and recorded during the hospital course of the patient.
Result: A total number of 110 patients were enrolled in this study. Blood glucose levels lower than or equal to10 mmol/L after MVR were present in 55(50%) patients (Group A) Blood glucose levels higher than 10 mmol/L after MVR were present in 55(50%) patients. Postoperative morbidity was higher in this group ( Group B) than in the patients who had peak blood glucose levels of less than or equal to 10 mmol/L MVR (p 0.001). Postoperative ICU stay was prolonged in patients with elevated levels of blood glucose after MVR under CPB compared with of patients with lower blood glucose levels (p 0.001). Other common morbidities are neurological complication (p 0.04), renal dysfunction (p 0.01) , wound infection (p 0.04), post-operative hospital stay ( p0.004). also higher in group B patient, as well as mortality.
Conclusions: Blood glucose concentration of 10.1 mmol/ L or higher after MVR under CPB is an important issues related to postoperative morbidity and mortality.
Bangladesh Heart Journal 2019; 34(1) : 44-51
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Wadud, Md Armane, Syed Dawood Md Taimur, Syed Tanvir Ahmed, Shanoor Aziz, Ibrahim Khalilullah, and CM Shaheen Kabir. "Effects of Controlling of Blood Glucose in Adult Non-Diabetic Patients Undergoing Mitral Valve Replacement." Anwer Khan Modern Medical College Journal 10, no. 2 (November 20, 2019): 114–20. http://dx.doi.org/10.3329/akmmcj.v10i2.44119.
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Background: The objective of this study was to see whether there is an association between high blood glucose levels after operation under CPB and post-operative morbidity and mortality. Methodology: This cohort study was carried out in the Department of Cardiac Surgery at National Institute of Cardiovascular Disease (NICVD), Sher-e-Bangla Nagar, Dhaka from January, 2012 to December, 2013 for a period of twenty four (24) months. A total number of 110 patients who underwent MVR operation with CPB were enrolled in this study as per inclusion and exclusion criteria. Patients were divided into two groups according to their blood glucose levels, recorded within first 60 hrs after Mitral Valve Replacement Surgery under Cardiopulmonay Bypass. Patients having blood glucose level of less than 10.1 mmol/L (unexposed) and patients having blood lactate level of 10.1 mmol/L or more (exposed) were grouped. Post operative variables were observed and recorded during the hospital course of the patient. Result: A total number of 110 patients were enrolled in this study. Blood glucose levels lower than or equal to10 mmol/L after MVR were present in 55(50%) patients (Group A) Blood glucose levels higher than 10 mmol/L after MVR were present in 55(50%) patients. Postoperative morbidity was higher in this group (Group B) than in the patients who had peak blood glucose levels of less than or equal to 10 mmol/L MVR (p=0.001). Postoperative ICU stay was prolonged in patients with elevated levels of blood glucose after MVR under CPB compared with of patients with lower blood glucose levels (p=0.001). Other common morbidities are Neurological complication (p=0.04), Renal dysfunction (p=0.01), wound infection (p=0.04), Post-operative hospital stay (p=0.004). also higher in group B patient, as well as mortality (p=0.31). Conclusions: Blood glucose concentration of 10.1 mmol/L or higher after MVR under CPB is an important issues related to postoperative morbidity and mortality
Anwer Khan Modern Medical College Journal Vol. 10, No. 2: July 2019, P 114-120
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Sideris, Konstantinos, Johannes Boehm, Bernhard Voss, Thomas Guenther, Ruediger S. Lange, and Ralf Guenzinger. "Functional and Degenerative Mitral Regurgitation: One Ring Fits All?" Thoracic and Cardiovascular Surgeon 68, no. 06 (September 23, 2019): 470–77. http://dx.doi.org/10.1055/s-0039-1696989.
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Abstract Background Three-dimensional saddle-shaped annuloplasty rings have been shown to create a larger surface of leaflet coaptation in mitral valve repair (MVR) for functional mitral regurgitation (FMR) and degenerative mitral regurgitation (DMR) which may increase repair durability. For the first time, this study reports mid-term results after MVR for DMR and FMR using a rigid three-dimensional ring (Profile 3D, Medtronic). Methods Between June 2009 and June 2012, 369 patients with DMR (n = 326) or FMR (n = 43) underwent MVR (mean age 62.3 ± 12.6 years). A total of 205 patients (55.6%) underwent isolated MVR and 164 patients (44.4%) a combined procedure. Follow-up examinations were performed in 94.9% (mean 4.9 ± 0.9 years). Echocardiographic assessment was complete in 93.2% (mean 4.3 ± 1.2 years). Results The 30-day mortality was 1.5% (5/326) for DMR (1.5% for isolated and 1.6% for combined procedures) and 9.3% (4/43) for FMR (0% for isolated and 10.5% for combined procedures). Survival at 6 years was 92.1 ± 1.9% for DMR (92.9 ± 2.6% for isolated and 90.7 ± 2.7% for combined procedures) and 66.4 ± 7.9% for FMR (80.0 ± 17.9% for isolated and 63.7 ± 8.9% for combined procedures). Cumulative risk for mitral valve-related reoperation at 6 years was 0% for FMR and 7.1 ± 1.5% for DMR. At echocardiographic follow-up, one patient presented with mitral regurgitation (MR) more than moderate. The only predictor of recurrent MR after MVR for DMR was residual mild MR at discharge. Conclusion Repair of FMR with the three-dimensional Profile 3D annuloplasty ring shows excellent mid-term results with regard to recurrence of MR. In cases of DMR, the results are conforming to the current literature.
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Myshakivskyy, Oleksiy. "RESULTS OF SURGICAL MANAGMENT OF PRIMARY MITRAL REGURGITATION IN A SINGLE-CENTER STUDY." EUREKA: Health Sciences 6 (November 30, 2017): 55–62. http://dx.doi.org/10.21303/2504-5679.2017.00516.
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Mitral regurgitation (MR) remains the second dominant defect in the structure of valvular cardiac diseases. It affects more than 2 million people in the USA. Basic causes are classified as degenerative (with valve prolapse) and ischemic (due to ischemic heart disease) in advanced countries or rheumatic ones (in developing countries). Alone radical method of MR treatment is surgical correction through mitral valve repair (MVRe) or replacement (MVR) yielding definitely higher survival percentage and improvement of heart failure (HF) class comparing to pharmacotherapy. Evolution of approaches to the management of non-ischemic MR passed through some stages starting from predominantly MVR to organ-preserving approaches like plastic repair. In the prospective single-center study were analyzed the results of treatment of 72 patients with primary MR (PMR) who were subjected to mitral valve replacement (MVR) or plastic mitral valve repair (MVRe) performed in the Department of cardiac surgery affiliated with Lviv regional clinical hospital (Ukraine) since October, 2013 till February, 2016. The conclusions of performed study are next: 1) Key direct cause of MR is the chordal rupture of MV cusps; etiological factor in the majority of advanced countries is degenerative changes in contrast to rheumatic changes in the developing countries. 2) Principal method of MR surgical correction in out center is MVR, though the preferable global trend is MVRe. 3) Complications and lethality percentages in this study were higher among the patients from MVR group. Improvement of HF class according to NYHA was more evident in the MVRe group. This corresponds to results of other studies and guidelines that recommend MVRe as optional method for MR correction.
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Zaman, MH, AM Asif Rahim, MZ Rashid, MK Hasan, MS Islam, and MK Sharker. "Early Outcome of Mitral Valve Replacement in Patient Having Mitral Stenosis with Moderate Pulmonary Hypertension." Cardiovascular Journal 13, no. 2 (April 15, 2021): 177–82. http://dx.doi.org/10.3329/cardio.v13i2.52972.
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Background: Mitral valve replacement (MVR) plays a central role in the management of patients with mitral stenosis with moderate to severe pulmonary hypertension. Pulmonary hypertension has an impact on short term outcome of MVR. It can influence left ventricular function (low output syndrome), incidence of arrhythmia, ARDS leading to respiratory failure and right ventricular failure which may be irreversible.
Methods: The immediate postoperative hemodynamics in 40 patients with moderate to severe pulmonary arterial hypertension who underwent mitral valve replacement (BLMV) between July 2010 and June 2012 were studied prospectively. Patients were divided into two groups: Group A (n=20): Patient having MS with moderate pulmonary hypertension (PASP: 40-59 mm-Hg) and Group B (n=20): Patient having MS with severe pulmonary hypertension (PASP e” 60mm-Hg). Total two follow up were done- 1st follow up after 10 days and 2nd follow up after 1 month of MVR. Each patient was assessed by medical history, clinical examination & color doppler echocardiogram.
Results: It was shown that surgery can be beneficial for the patients if MVR is done in the state of mild PAH irrespective of age but beyond this level of PAH, the patients may still remain with mild pulmonary hypertension which may trigger the cascade of pulmonary vascular Disease may be the cause of unsatisfactory outcome. So, early surgical outcome of mitral stenosis with moderate pulmonary hypertension is better than mitral stenosis with severe pulmonary hypertension.
Conclusion: We conclude that MVR in patients having MS with moderate PAH is a safe and effective measures for preventing pulmonary hypertension related complications.
Cardiovasc. j. 2021; 13(2): 177-182
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Vadillo, Jose Manuel, Lucia Gómez-Coma, Aurora Garea, and Angel Irabien. "CO2 Desorption Performance from Imidazolium Ionic Liquids by Membrane Vacuum Regeneration Technology." Membranes 10, no. 9 (September 14, 2020): 234. http://dx.doi.org/10.3390/membranes10090234.
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In this work, the membrane vacuum regeneration (MVR) process was considered as a promising technology for solvent regeneration in post-combustion CO2 capture and utilization (CCU) since high purity CO2 is needed for a technical valorization approach. First, a desorption test by MVR using polypropylene hollow fiber membrane contactor (PP-HFMC) was carried out in order to evaluate the behavior of physical and physico-chemical absorbents in terms of CO2 solubility and regeneration efficiency. The ionic liquid 1-ethyl-3-methylimidazolium acetate, [emim][Ac], was presented as a suitable alternative to conventional amine-based absorbents. Then, a rigorous two-dimensional mathematical model of the MVR process in a HFMC was developed based on a pseudo-steady-state to understand the influence of the solvent regeneration process in the absorption–desorption process. CO2 absorption–desorption experiments in PP-HFMC at different operating conditions for desorption, varying vacuum pressure and temperature, were used for model validation. Results showed that MVR efficiency increased from 3% at room temperature and 500 mbar to 95% at 310K and 40 mbar vacuum. Moreover, model deviation studies were carried out using sensitivity analysis of Henry’s constant and pre-exponential factor of chemical interaction, thus as to contribute to the knowledge in further works.
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Suzuki, Hideaki. "Operation Experience of MVR Pre-Eva." JAPAN TAPPI JOURNAL 68, no. 8 (2014): 876–79. http://dx.doi.org/10.2524/jtappij.68.876.
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Suzuki, Hideaki. "Operation Experience of MVR Pre-Eva." JAPAN TAPPI JOURNAL 69, no. 4 (2015): 355–59. http://dx.doi.org/10.2524/jtappij.69.355.
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AKKIN, CEZMI, and TANSU ERAKGUN. "MARKED MVR KNIFE FOR VITREORETINAL SURGERY." RETINA 23, no. 2 (April 2003): 270–71. http://dx.doi.org/10.1097/00006982-200304000-00034.
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Karevа, Yu E., V. U. Efendiev, S. S. Rakhmonov, A. M. Chernyavsky, and V. L. Lukinov. "Long-Term Survival of Patients with Ischemic Heart Disease After Surgical Correction of Moderate Ischemic Mitral Regurgitation." Kardiologiia 59, no. 9 (September 21, 2019): 13–19. http://dx.doi.org/10.18087/cardio.2019.9.2635.
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Aim: to assess effect of correction of moderate ischemic mitral regurgitation (IMR) in patients with ischemic cardiomyopathy (IMC) in immediate and remote period. Materials and methods. We included in a single center prospective study 76 patients with IMC, left ventricular ejection fraction ≤35 %, and moderate IMR. Patients with indications to postinfarction aneurism repair were not included. For randomization we used the method of envelopes. Thirty-eight patients were randomized in the group where coronary artery bypass grafting (CABG) was combined with of mitral valve repair (MVR), and 38 patients in the control group of isolated CABG. Mean age of patients was 57±8 (from 30 to 75 лет) years. For IMR correction we used rigid MEDENG ring. Results. Inhospital mortality was 5.4 % (n=2) after isolated CABG and 10.81 % (n=4) after CABG + MVR. Main cause of death was acute heart failure. One- and 2‑year survival was 84 and 78 %, respectively, after CABG+MVR, and 84 and 71 % after isolated CABG. There was significant difference in three-year survival between groups (hazard ratio [HR] of death 0.457, p=0.04). Five-year survival was 45 and 74 % after isolated CABG and CABG+MVR, respectively (р=0.037). Factors associated with inhospital mortality were pulmonary hypertension (HR 2.177, 95 % confidence interval [CI] 2.299 to 9.831; p=0.043), NYHA class IV chronic heart failure (HR 3.027, 95 % CI 1.605 to 5.707; р=0.001), negative result of stress test echocardiography (HR 0.087, 95 %CI 0.041 to 0.186; р<0.001), atrial fibrillation (HR 4.754, 95 %CI 2.299 to 9.831; р<0.001). Conclusion. Correction of moderate IMR in patients with IMC leads to improvement of parameters of survival in remote period. Five-year survival after isolated CABG was 45 %, while after CABG+MVR – 74 % (р=0.037).
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Shariff, Masood A., Laura Klingbeil, Daniel Martingano, Robert F. Carlucci, Rami Michael, Jonathan Davila, Scott M. Sadel, John P. Nabagiez, and Joseph T. McGinn Jr. "Minimally Invasive Valve Surgery and Single Vessel Coronary Artery Bypass via Limited Anterior Right Thoracotomy." Heart Surgery Forum 18, no. 6 (December 21, 2015): 266. http://dx.doi.org/10.1532/hsf.1319.
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<strong>Background:</strong> Coronary artery bypass grafting with aortic valve replacement (AVR) or mitral valve replacement (MVR) is traditionally performed via sternotomy. Minimally invasive coronary surgery (MICS) and minimally invasive valve surgery have been successfully performed independently. Patients with critical right coronary artery (RCA) stenosis not amenable to percutaneous intervention are candidates for valve replacement and single vessel coronary artery bypass. We present our series of six patients who underwent a concomitant valve and single vessel intervention via right thoracotomy.<br /><strong>Methods:</strong> Between January 2011 and June 2013, six patients underwent right thoracotomy with valve replacement and single vessel bypass. Four aortic and two mitral valves were replaced and all received single vessel RCA bypass using reversed saphenous vein graft. Thoracotomy was via right anterior approach for AVR and right lateral for MVR. The patients were assessed postoperatively for overall outcomes.<br /><strong>Results:</strong> The average age was 74 years (range 69-81); two patients were elective (AVR-1; MVR-1) and four were urgent (AVR-3; MVR-1). For MICS AVR and MICS MVR, the average cardiopulmonary bypass time was 171 ± 30 and 169 ± 7 minutes and the average aortic cross-clamp time was 122 ± 36 and 112 ± 2 minutes, respectively. Three patients were discharged home, one patient to a nursing home, and two to rehab. No patients required conversion to sternotomy; one patient developed atrial fibrillation, and one sepsis. <br /><strong>Conclusion:</strong> Concomitant valve replacement and single bypass grafting via right anterior mini-thoracotomy is a viable option for select patients, particularly in non-stentable RCA stenosis. In the appropriate patient population, combined coronary artery bypass grafting and valve surgery can be safely performed via right thoracotomy.
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Husaini, Mustafa, Nishath Quader, Alan C. Braverman, Ralph J. Damiano, and Hersh S. Maniar. "Massive Left Atrial Thrombus After a Left Atrial Surgical Ablation and Bioprosthetic Mitral Valve Replacement." Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery 15, no. 4 (July 2020): 389–92. http://dx.doi.org/10.1177/1556984520934632.
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Variability exists regarding the timing and duration of anticoagulation after surgical ablation for atrial fibrillation and bioprosthetic mitral valve replacement (MVR). We report a case in which a patient developed a massive left atrial (LA) thrombus after MVR and left-sided radiofrequency ablation (LRFA). Despite acutely elevated gradients across the bioprosthetic valve, the patient remained asymptomatic and hemodynamically stable; thus, a multidisciplinary, patient-centered discussion was had and the patient was treated successfully with oral anticoagulation.
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F. El-Safty, Mahmoud, Hazem Gamal Bakr, Mohamed A. El Badawy, Mohamed Abd El-Hady, and Yahia Mahmoud. "IMPACT OF THE PRESERVATION OF THE SUBVALVULAR APPARATUS OF THE ANTERIOR MITRAL LEAFLET ON THE LEFT VENTRICULAR FUNCTION AFTER MITRAL VALVE REPLACEMENT IN EARLY POST-OPERATIVE PERIOD." International Journal of Advanced Research 8, no. 11 (November 30, 2020): 1030–47. http://dx.doi.org/10.21474/ijar01/12100.
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Background:Long-term morbidity and mortality appear to be associated with mitral valve replacement for mitral valve disease. The morbidity rate has not decreased dramatically over the years, despite enhancements in myocardial safety and prosthetic valves. Cardiac failure is the most common cause of death following MVR. Subvalvular apparatus preservation preserves LV function and thus improves survival. Repair, particularly with rheumatic valve disease in young patients and extremely disorganised valves, is not always feasible or effective. The use of smaller valve prothesis was not only the argument of preserving the anterior leaflet, but also that it could cause LVOT obstruction. Methods:A prospective controlled randomized study will include(sixty patients aged from 25 to 55 years of both sexes) They will be divided into two groups of patients: Group I: thirty patients who underwent MVR without preservation of The chordae tendinae of the anterior mitral leaflet and only preserving the posterior mitral leaflet. Group II: thirty patients who underwent MVR with complete or partial Preservation of the chordae tendinaeof the anterior mitral leaflet. Results:The sixty patients were divided into two groups where 30 of them underwent preservation of AML, These patients had a better LV function in the early and the short term postoperative period. Conclusion:Results of this study concluded that preservation of the AML leads to better postoperative outcome. We recommend its application on a greater scale of cases of MVR.
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Smirnov, A. V., A. I. Cherepanin, and R. V. Ishchenko. "Is there a place for multivisceral resections in the treatment of gastric cancer?" Almanac of Clinical Medicine 47, no. 8 (January 1, 2020): 707–11. http://dx.doi.org/10.18786/2072-0505-2019-47-081.
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It is known that multivisceral resections (MVR) are associated with significant numbers of post-operative complications. However, the effectiveness of MVR in increasing the patients' life expectancy remains a matter of debate. Are the risks of extended volume resections justified? It has been previously assumed that the removal of adjacent organs could improve the prognosis of the disease, even in the absence of direct invasion. However, in the era of the big potential of chemoand radiation therapy, the implementation of an over-extensive surgical volume in the absence of tumor invasion is doubtful. In the presence of regional lymphatic nodes metastases, MVR do not improve prognosis, compared to that after palliative resections. If the patient has distant metastases, or the operation has been obviously not radical enough, MVR worsen the prognosis. In grade T4b invasion and with the absence of life threatening complications, it is optimal to start with neoadjuvant or perioperative chemotherapy. In the case of intraoperative suspicion of adjacent anatomical structures involvement, with no distant metastases, en bloc resection in combination with D2 lymphodissection is indicated. In approximately 30–60% of cases, invasion is not confirmed by histology. The only way to improve the results of surgical treatment of gastric cancer patients is to carefully assess the extension of the disease at the preoperative stage, select patients and team work of surgeons with chemotherapists, radiologists and specialists in diagnostics.
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Ozdemir, Ahmet Coskun, Bilgin Emrecan, and Ahmet Baltalarli. "Bileaflet versus Posterior-Leaflet-Only Preservation in Mitral Valve Replacement." Texas Heart Institute Journal 41, no. 2 (April 1, 2014): 165–69. http://dx.doi.org/10.14503/thij-13-3164.
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In the present study of mitral valve replacement, we investigated whether complete preservation of both leaflets (that is, the subvalvular apparatus) is superior to preservation of the posterior leaflet alone. Seventy patients who underwent mitral valve replacement in our clinic were divided into 2 groups: MVR-B (n=16), in whom both leaflets were preserved, and MVR-P (n=54), in whom only the posterior leaflet was preserved. The preoperative and postoperative clinical and echocardiographic findings were evaluated retrospectively. No signs of left ventricular outflow tract obstruction were observed in either group. In the MVR-B group, no decrease was observed in left ventricular ejection fraction during the postoperative period, whereas a significant reduction was observed in the MVR-P group (P=0.003). No differences were found between the 2 groups in their need for inotropic agents or intra-aortic balloon pump support, or in cross-clamp time, duration of intensive care unit or hospital stays, postoperative development of new atrial fibrillation, or mortality rates. Bileaflet preservation prevented the decrease in left ventricular ejection fraction that usually followed preservation of the posterior leaflet alone. However, posterior leaflet preservation alone yielded excellent results in terms of decreased left ventricular diameter. Bileaflet preservation should be the method of choice to prevent further decreases in ejection fraction and to avoid death in patients who present with substantially impaired left ventricular function.
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Zheng, Junnan, Tingting Tao, Yiming Ni, Liang Ma, and Haige Zhao. "Small Cavity of Left Ventricle Does Not Affect Short-term Outcome in Patients with Rheumatic Mitral Valve Stenosis Undergoing Mitral Valve Replacement." Heart Surgery Forum 24, no. 1 (January 15, 2021): E031—E037. http://dx.doi.org/10.1532/hsf.3335.
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Background: Small cavity left ventricle (SCLV) may affect the clinical outcomes of patients undergoing mitral valve replacement (MVR). This study aims to investigate the incidence of SCLV in patients with rheumatic mitral valve stenosis undergoing MVR and analyze its effect on short-term patient outcomes. Methods: We retrospectively examined all consecutive patients with isolated or concomitant MVR for rheumatic mitral valve stenosis in our center from 2013 to 2018. SCLV was defined as end-diastolic volume index ≤ 50 ml/m2. After inclusion and exclusion, a total of 1,437 patients were analyzed. The baseline information was collected and compared between SCLV and non-SCLV patients. Multivariate logistic regression analysis was conducted to determine the effect of SCLV on early mortality. Results: A total of 1,437 patients were included in the study. SCLV was detected in 13.57% of the patients. Compared with the non-SCLV group, patients with SCLV were smaller-sized and primarily female. There were no significant differences between SCLV and non-SCLV patients regarding major postoperative complications, nor were there incidence of prosthesis-patient mismatch. Logistic regression analysis showed that SCLV was not a risk factor for short-term mortality (P = 0.998). Conclusions: Our results demonstrated that SCLV was not associated with poorer early outcomes after MVR surgery in patients with rheumatic mitral valve stenosis.
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Joung, Kyoung-Woon, Seon-Ok Kim, Jae-Sik Nam, Young-Jin Moon, Hyeun-Joon Bae, Ji-Hyun Chin, Sung-Ho Jung, and In-Cheol Choi. "Changes in Left Ventricular Ejection Fraction after Mitral Valve Repair for Primary Mitral Regurgitation." Journal of Clinical Medicine 10, no. 13 (June 26, 2021): 2830. http://dx.doi.org/10.3390/jcm10132830.
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This study sought to identify the short- and long-term changes in left ventricular ejection fraction (LVEF) after mitral valve repair (MVr) in patients with chronic primary mitral regurgitation according to preoperative LVEF (pre-LVEF) and preoperative left ventricular end-systolic diameter (pre-LVESD). This study evaluated 461 patients. Restricted cubic spline regression models were constructed to demonstrate the long-term changes in postoperative LVEF (post-LVEF). The patients were divided into four groups according to pre-LVEF (<50%, 50–60%, 60–70%, and ≥70%). The higher the pre-LVEF was, the greater was the decrease in LVEF immediately after MVr. In the same pre-LVEF range, immediate post-LVEF was lower in patients with pre-LVESD ≥ 40 mm than in those with pre-LVESD < 40 mm. The patterns of long-term changes in post-LVEF differed according to pre-LVEF (p for interaction < 0.001). The long-term post-LVEF reached a plateau of approximately 60% when the pre-LVEF was ≥50%, but it seemed to show a downward trend after reaching a peak at approximately 3–4 years after MVr when the pre-LVEF was ≥70%. The patterns of short- and long-term changes in post-LVEF differed according to pre-LVEF and pre-LVESD values in patients with chronic primary mitral regurgitation after MVr.
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Šmíd, Michal, Jakub Čech, Richard Rokyta, Patrik Roučka, and Tomáš Hájek. "Mild to Moderate Functional Tricuspid Regurgitation: Retrospective Comparison of Surgical and Conservative Treatment." Cardiology Research and Practice 2010 (2010): 1–5. http://dx.doi.org/10.4061/2010/143878.
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Background. Unoperated severe tricuspid regurgitation (TR) leads to the right ventricle (RV) failure. We wanted to determine if there was near-term postoperative progression of noncorrected mild to moderate functional TR in patients who underwent mitral valve surgery for chronic significant mitral regurgitation (MR) and if RV size and function were affected.Methods and Results. We compared two groups of patients retrospectively. In the first group (TVA+, ), tricuspid valve annuloplasty (TVA) had been performed in conjunction with either mitral valve replacement (MVR) or mitral valve repair (MVP). The second group (TVA−, ) underwent MVP or MVR without TVA. TVA+ group revealed a significant decrease in TR and right ventricle diameter. In the TVA− group, 7 patients (32%) showed a significant progression, by one or more grades, of noncorrected TR together with dilatation and decreased ejection fraction of the right ventricle.Conclusions. Tricuspid annuloplasty performed concurrently with MVP or MVR can prevent subsequent progression of tricuspid regurgitation along with right ventricular dilatation and systolic dysfunction in the near-term postoperative period.
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Abdelnoor, M., K. V. Hall, S. Nitter-Hauge, H. Rostad, and Ø. Risum. "Morbidity in Valvular Heart Replacement: Risk Factors of Systemic Emboli and Thrombotic Obstruction." International Journal of Artificial Organs 11, no. 4 (July 1988): 303–7. http://dx.doi.org/10.1177/039139888801100414.
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A study on a cohort of 839 patients with valvular heart replacement between June 1977 and May 1985 showed that the linearized rates of systemic emboli and thrombotic obstruction were 1.4/100 pts/year for Aortic Valve Replacement (AVR), 2.2/100 pts./year for Mitral Valve Replacement, and 3.00/100 pts./year for Double Valve Replacement (DVR). The 5-year free-from-thromboembolism (TE) survival was 95% for AVR and 92% for MVR. The hazard function (the instantaneous risk) for TE peaked in the first six months after operation for AVR and MVR. Another analysis using the Cox regression model to estimate risk factors of systemic emboli and thrombotic obstruction pinpointed two factors in the AVR group: presence of aortic regurgitation (AR) and age at operation. In the MVR group the sole predictor covariate was sex of the patients, with a higher hazard for females. Our results underline the importance of patient-related factors besides the type of prosthesis as predictors of morbidity from TE.