Academic literature on the topic 'WW 2480'

Ellis, John, Ricky Fok, Dae Sung Hwang, Verónica Sanz та Tevong You. "Distinguishing ‘Higgs’ spin hypotheses using γγ and WW ∗ decays". European Physical Journal C 73, № 7 (2013). http://dx.doi.org/10.1140/epjc/s10052-013-2488-5.

"Published: July 26, 2018| Views: 52| DOI: 10.1510/mmcts.2018.043 Surgical Videos Abstract Hide - Creation of a subclavicular arteriovenous fistula is a minimally invasive procedure that provides an additional source of arterial blood flow to the pulmonary arteries in patients who have a Glenn shunt but are unsuitable for or at high risk for Fontan completion. Introduction Hide - Patients who have contraindications for Fontan completion usually remain with a (bidirectional) Glenn shunt. With time arterial oxygen saturation becomes lower* and an additional source of pulmonary blood flow is then needed. One option is to leave antegrade blood flow through a banded pulmonary artery. Alternatively, a modified Blalock or central shunt may be considered. However, all these procedures carry the risk of pulmonary artery distortion and are invasive, due to the need for resternotomy or rethoracotomy in patients who already may have undergone several thoracic procedures. In this situation, subclavicular fistula creation is much less invasive but as effective as other shunt procedures [1, 2]. The fistula can be used as a palliative end-stage procedure, a bridge to transplantation [2-5], or, in rare instances, as a bridge to complete Fontan palliation [6]. This arteriovenous (AV) connection usually increases arterial oxygen saturation from 8-10% [2-4] and as a result decreases blood viscosity, leading to improvement of dyspnea, cyanosis, and exercise tolerance, together with improvement in NYHA functional class [2-5, 6]. This video tutorial demonstrates the technical aspects of creating an AV subclavicular fistula. Patient Presentation Hide - The patient presented in this video tutorial is a 4-year-old child with mitral atresia who underwent Fontan completion in 2011 through the stages of a modified Blalock-Taussig shunt procedure, bidirectional Glenn, and total cavopulmonary connection. She had a Fontan take-down 1 month later for failing circulation. Her condition progressively deteriorated and she was considered unsuitable for a redo Fontan operation. She was then referred for fistula creation. Surgical Technique & Videos Hide - video-icon 1 - Preoperative evaluation and surgical incision (00:01) Preoperative vascular echo investigated the patency of the subclavicular artery and vein on both sides. The fistula is usually performed on the nondominant arm but, if necessary, it can be done on the other side or even on both, if any complication occurs. Preoperative catheterisation is recommended to exclude the presence of venovenous collaterals and to close them by coil if present. The patient is under general anesthesia. A 3-cm incision is made below the lateral half of the clavicle.The pectoralis major muscle is dissected and split along its fibers. Most of our AV fistula surgeries have been done in patients who had a Glenn shunt but were unsuitable for Fontan completion. The AV fistula usually results in 5-10% increase in oxygen saturation and thereby in improvement in physical conditions. video-icon 2 - Identifying vascular and nervous structures (01:10) The pectoralis minor is then transected at the level of the flat tendon attached to the coracoid process of the scapula and kept in place with standing sutures. The brachial plexus, wrapped along the superior and posterior wall of the subclavian artery, is identified and carefully spared. The subclavian vein and the artery, which usually runs slightly higher and deeper than the vein, are isolated and mobilized, ligating the collateral vessels if necessary. video-icon 3 - Arteriovenous anastomosis (02:25) After administration of 100 U/kg body weight heparin sulphate, a vascular clamp is placed across the artery and the vein is ligated at its distal end. An end-to-side anastomosis of the vein on the subclavian artery, matching in length the diameter of the vein, is performed with a 6/0 running Prolene suture. All visible systemic venous collaterals are ligated to avoid flow stealing. At the end of the procedure it is important to feel the fistula and make sure there is a thrill, as this identifies that it is functioning properly. Closure is made respecting the anatomical planes. The pectoralis minor muscle is again resutured. Our recommendation is to keep the patient’s arm higher than the heart for the first few days after surgery and to administer postoperative aspirin for 6 months. The arm involved in the procedure should not be subjected to IV injections or invasive vascular procedures, or be used for withdrawal of blood samples for at least 3 months postprocedure. Vascular echo controls are needed in order to detect later aneurysmatic evolution of the fistula and to assess its patency in the long term. Outcome & Discussion Hide - Alternative approaches are needed for patients with single ventricle and a (bidirectional) Glenn shunt where there is a deterioration in clinical condition and Fontan completion is contraindicated. When oxygen saturation decreases an extra source of pulmonary blood flow is needed. If the surgeon wants to avoid (re-)opening of the thorax, a subclavicular arteriovenous fistula should be considered, as is the least invasive therapeutic approach. Subclavicular arteriovenous fistula was first introduced as a palliative intervention to increase pulmonary blood flow in the early 70s by Glenn and Fenn, with their direct cavopulmonary anastomosis (the classic Glenn shunt). The procedure was then modified and combined with a Kawashima operation in an attempt to prevent or alleviate intrapulmonary shunt caused by arteriovenous malformations (AVM) in patients without hepatic venous blood stream directed to the lungs [5, 6]. However, results for the latter indication did not show significant reduction of AVM and results in patients who had AVM were less effective than in those without pulmonary AVM [2, 6]. Subclavicular arteriovenous fistula is indicated for patients who need more pulmonary blood flow and who have: Bidirectional Glenn shunt. Single-sided cavopulmonary anastomosis (classic Glenn shunt). Failing Fontan circulation. Kawashima operation (cavopulmonary anastomosis with hepatic veins draining into the heart). The procedure can be used as a bridge to complete palliation, a bridge to transplantation, or - usually - as a palliative end-stage procedure in patients suffering from progressive cyanosis and desaturation. It increases arterial saturation by an average of 8-10% and as a result decreases blood viscosity [2-6]. In our institution, between April 1997 and April 2018 we created 14 AV fistulas in patients with single ventricle physiology, with a median follow-up of 27 months (range 1-240 months) (Figure 1). The long-term patency rate of the fistulas is optimal and well-functioning in all patients but one, who had occlusion 12 months after operation. In this case we observed clinical worsening and we performed the fistula on the other side. Another patient underwent surgical closure of the fistula after 8 years, at the time of complete palliation (Fontan completion). table 1 Figure 1: The arteriovenous fistula Abbreviations: HLHS, hypoplastic heart syndrome; PA-IVS, pulmonary atresia-intact ventricular septum; PS, pulmonary stenosis; AVSD, atrioventricular septal defect; DILV, double inlet left ventricle; DORV, double outlet right ventricle. Our preferred technique is direct end-to-side anastomosis, without interposition of any prosthetic material. Ligation of the axillary vein is always performed in order to increase the effectiveness of the fistula and to avoid postoperative swelling and paraesthesia. All the procedures were uncomplicated and all patients experienced direct improvement in saturation and reduction of cyanosis. Reviewing the literature, we find no agreement regarding contraindications for subclavicular AV fistula, but some concerns have been raised in cases of: Venous/pulmonary hypertension (central venous/pulmonary pressure >18 mmHg). Severe systemic AV valve failure (regurgitation grade 3 or 4). Compromised blood flow in the axillary artery. Presence of significant venovenous shunts between the superior vena cava and veins draining to the IVC or to the pulmonary veins [2]. In this situation it is helpful to attempt coil closure of as many collaterals as possible before scheduling the operation. In conclusion, this approach should be considered in any patient who requires an increase in oxygen saturation and is not a candidate for completion of the Fontan circulation. It can be used also in patients with impaired ventricular function, because the small left-to-right shunt does not lead to volume overload, and indeed slightly reduces the post-load, without worsening ventricular function. The fistula improves saturation and thereby functional capacity in all patients and does not preclude any later intervention. References Hide - 1. Glenn WW, Fenn JE. Axillary arteriovenous fistula. A means of supplementing blood flow through a cava-pulmonary artery shunt. Circulation 1972;46:1013–17. PubMed Abstract 2. Yurlov IA, Podzolkov VP, Kovalev DV, Zelenikin MM, Samsonov VB, Chikin NS et al. Indications for and results of axillary arterio-venous fistula in patients with a functionally single ventricle after cavopulmonary anastomosis. Eur J Cardiothorac Surg 2018. PubMed Abstract | EJCTS Full Text 3. Hickey EJ, Alghamdi AA, Elmi M, Al-Najashi KS, Van Arsdell GS, Caldarone CA et al. Systemic arteriovenous fistulae for end-stage cyanosis after cavopulmonary connection: a useful bridge to transplantation. J Thorac Cardiovasc Surg 2010;139:220–5. PubMed Abstract | Publisher Full Text 4. Chanana N, Day RW, McGough EC, Burch PT. Outcome Following augmentation of superior cavopulmonary blood flow with an arteriovenous fistula. World J Pediatr Congenit Heart Surg 2015;6:220–5. PubMed Abstract | Publisher Full Text 5. Magee A, Sim E, Benson LN, Williams WG, Trusler GA, Freedom RM. Augmentation of pulmonary blood flow with an axillary arteriovenous fistula after a cavopulmonary shunt. The Journal of Thoracic and Cardiovascular Surgery 1996;111(1):176–180. PubMed Abstract | Publisher Full Text 6. Quarti A, Oggianu A, Soura E, Colaneri M, Colonna PL, Pozzi M. Brachial arteriovenous fistula in patients with cavopulmonary connection and poor ventricular function: a bridge to Fontan operation. J Card Surg 2011;26:415–19. PubMed Abstract | Publisher Full Text Author & Tutorial Information Hide - Authors Federica Caldaroni, Timofey Nevvazhay, Vladimir Sojak, and Mark Hazekamp Authors Affiliation Department of Cardio-thoracic surgery, LUMC, Leiden, The Netherlands Corresponding Author Federica Caldaroni Department of Cardio-thoracic surgery, LUMC, Leiden, The Netherlands Keywords Subclavicular arterio-venous fistulaCava-pulmonary anastomosisCyanosisSingle ventricleFontan procedure © The Author 2018. Published by MMCTS on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. 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