Abstract The rotary blood pump (the HeartWare® Ventricular Assist Device) from HeartWare® (Medtronic) is an established left ventricular assist device and usually implanted via sternotomy. To reduce the invasiveness of the implant procedure and to optimize the position of the inflow cannula, we propose an alternative implant technique with an extrapericardial placement of the pump via left anterolateral minithoracotomy. However, the minimally invasive approach is not suitable in patients in need of an additional cardiac procedure or with thrombus formation in the left atrial appendix. Preservation of the pericardium may reduce adhesions in future surgery such as heart transplantation, and an ‘off pump’ thoracotomy approach is feasible in patients without intraventricular thrombus. Left ventricular assist device, HeartWare®, HVAD, minimally invasive, mcs INTRODUCTION The implantation of left ventricular assist devices (LVADs) is an established therapy in patients with end-stage heart failure. One of the most common LVADs is the HeartWare® Ventricular Assist Device. The HeartWare® Ventricular Assist Device (Medtronic, formerly HeartWare, Inc., Miramar, FL, USA) is a centrifugal ventricular pump, which provides full support. The common implantation technique utilizes a midline incision and full sternotomy. To reduce the invasiveness of the implantation, we propose an upper hemisternotomy for access to the ascending aorta to perform the anastomosis of the outflow graft and an anterolateral thoracotomy for the access to the apex for pump implantation. A left thoracotomy was earlier described by Gregoric et al.  for implantation of a left ventricular assist device. This incision was also used several times for an LVAD exchange or explantation [2, 3]. Possible thrombus formation in the left atrial appendix or a significant patent foramen ovale has to be excluded prior to the implantation via echocardiography, as well as the need for an additional procedure such as aortic/mitral valve replacement or a coronary artery bypass to the right coronary artery. Utilization of 3-dimensional echocardiography is necessary to evaluate the possibility of interference of the papillary muscle with thrombus formation. IMPLANTATION TECHNIQUE Initially, an L-shaped upper hemisternotomy is performed using an incision at the 3rd intercostal space, Video 1. The ascending aorta is exposed for possible cardiopulmonary bypass (CPB) and for the anastomosis of the outflow graft. Afterwards, the anterolateral thoracotomy is performed in the 6th intercostal space. Pericardial sutures are applied for exposure of the apex. A needle is inserted in the apex at the possible position for the placement of the inflow cannula. After verification of a proper needle position using 3-dimensional echocardiography (Fig. 1), the sewing ring is attached to the epicardial surface on the distal left ventricular anterior wall approximately 2 cm lateral to the left anterior descending coronary artery using 12–15 interrupted epicardial Seracor sutures supported with Teflon felts. A loosening of the screw of the sewing ring is done, if the sewing ring is too tight. Glue can be administered around the sewing ring and the sutures for sealing and stabilization. If no bleeding is detected, Heparin is given. A CPB is initiated via the ascending aorta and femoral vein. Reduced mechanical ventilation is continued during CPB. The table is positioned for deepening the upper part of the body. After coring of the left ventricle on the beating heart using the apical coring tool, the left ventricular cavity is inspected for thrombi and crossing chordae tendineae, meanwhile the patient is on CPB or on ECLS. Thrombus formation of the left ventricle has to be removed meticulously. Then, the inflow cannula of the pump is inserted into the left ventricle and fixed by tightening of the screw of the sewing ring. Finally, the outflow graft is tunnelled in the pericardium to the ascending aorta. After partial clapping of the aorta, the anastomosis is performed. The correct length of the outflow graft is measured by a gentle stretch of the graft due to a lengthening of the prosthesis in running pumps. To avoid any twist of the outflow you can orientate at the black line at the prosthesis. In redo cases, the graft is placed in the left pleural space. In case of prior coronary bypass surgery with the use of the left mammaria arteria adhesions in the left pleural space can make use of a left thoracotomy impossible due to injuries of the lungs for tunnelling of the outflow graft. Figure 1: View largeDownload slide Echocardiography of the left ventricle with the correct position of the needle after puncture of the apex. Figure 1: View largeDownload slide Echocardiography of the left ventricle with the correct position of the needle after puncture of the apex. Video 1 Less invasive HeartWare left ventricular assist device implantation. Video 1 Less invasive HeartWare left ventricular assist device implantation. Close The exit site for the driveline is mostly placed in the right upper abdominal quadrant. The velour part of the driveline should be placed completely below the skin, whereas the silicon part is entirely outside. For primary wound healing, a stable fixation of the driveline is essential. The pump is started against the clamped outflow graft for deairing. After filling of the heart, the clamp is released, and weaning from CPB can be performed with the use of echocardiography. Before chest closure, the pump is covered with epipericardial fat if possible. When an right ventricular assist device (RVAD) is needed, it is also possible to implant an RVAD via minimal approach using an upper hemisternotomy. An 8–10-mm prosthesis can be fixed to the pulmonary artery and tunnelled through the skin. The right atrium can be relieved via venous cannula from the femoral vein. A switch from an L-shaped to a T-shaped upper hemisternotomy can be useful. A pump exchange or pump explantation can be done via left anterolateral thoracotomy. An additional hemisternotomy is dependent on the need for a replacement of the outflow graft due to an occlusion. DISCUSSION The minimally invasive approach using an upper hemisternotomy and lateral thoracotomy demonstrates comparable results to other studies using a full sternotomy approach for LVAD implantation . Cumulative survival was not significantly different. Patients with a less invasive approach had a shorter median length of stay and a lower incidence of post-implant pump thrombus (P = 0.02) . This approach also enables implantation without the use of a heart–lung machine. The heart does not need to be lifted in the chest, and the sewing ring can be fixed comfortably to the apex with the heart in its original position. A close collaboration and interaction with your anaesthesiologist is mandatory to maintain stable haemodynamics. Avoiding the use of a heart-lung machine may avert the potential side effects of CPB. A target ACT above 200 is sufficient for implantation. This could be beneficial in patients with a heparin-induced thrombocytopenia, where alternative anticoagulation medications are used . During the implantation in the complete off-pump technique, rapid pacing can be induced to facilitate application of the punch and insertion of the pump followed by a careful final deairing. However, when the bypass is used, e.g. for thrombus excision or in unstable situation, heparin and the extracorporeal support can be administered after the apical sewing ring is in place. Therefore, the CPB time can be kept very short. In patients under ECLS prior to LVAD implantation, no additional CPB is required, and the minimally invasive implantation can be performed as described above. When performing the minimally invasive approach, the lateral thoracotomy incision should not be too small. If the incision is very small, the pump can get stuck and lift the sewing ring. Too much strength to the sewing ring can result in the rupture of the left ventricle. The anastomosis to the ascending aorta via hemisternotomy was performed rather than anastomosis to the descending aorta because earlier results demonstrated a tendency for thrombosis of the ascending aorta or aortic root . The anastomosis of the outflow graft can also be done via minimal right thoracotomy of the 2nd intercostal space . The impact on subsequent surgeries has yet to be evaluated. In non-redo cases with a minimally invasive LVAD implantation, the outflow graft is tunnelled in the pericardium to the ascending aorta. Therefore, adhesions are avoided between the outflow graft and the lungs and sternum. However, in redo cases, the outflow graft is tunnelled outside the pericardium in the left pleura space. Regardless of the surgical expertise, close collaboration of the team and intraoperative imaging are essential in performing a successful minimally invasive LVAD implantation. Conflict of interest: none declared. REFERENCES 1 Gregoric ID , La Francesca S , Myers T , Cohn W , Loyalka P , Kar B et al. A less invasive approach to axial flow pump insertion . J Heart Lung Transplant 2008 ; 27 : 423 – 6 . Google Scholar CrossRef Search ADS PubMed 2 Schweiger M , Potapov E , Vierecke J , Stepanenko A , Hetzer R , Krabatsch T. Expeditious and less traumatic explantation of a heartware LVAD after myocardial recovery . ASAIO J 2012 ; 58 : 542 – 4 . Google Scholar CrossRef Search ADS PubMed 3 Sajjad M , Butt T , Oezalp F , Siddique A , Wrightson N , Crawford D et al. An alternative approach to explantation and exchange of the HeartWare left ventricular assist device . Eur J Cardiothorac Surg 2013 ; 43 : 1247 – 50 . Google Scholar CrossRef Search ADS PubMed 4 Maltais S , Anwer LA , Tchantchaleishvili V , Haglund NA , Dunlay SM , Aaronson KD et al. Left lateral thoracotomy for centrifugal continuous-flow left ventricular assist device placement: an analysis from the Mechanical Circulatory Support Research Network . ASAIO J 2017 , doi: 10.1097/MAT.0000000000000714. 5 Morshuis M , Boergermann J , Gummert J , Koster A. A modified technique for implantation of the HeartWare left ventricular assist device when using bivalirudin anticoagulation in patients with acute heparin-induced thrombocytopenia . Interact CardioVasc Thorac Surg 2013 ; 17 : 225 – 6 . Google Scholar CrossRef Search ADS PubMed 6 Feldman D , Pamboukian SV , Teuteberg JJ , Birks E , Lietz K , Moore SA et al. The 2013 International Society for Heart and Lung Transplantation Guidelines for mechanical circulatory support: executive summary . J Heart Lung Transplant 2013 ; 32 : 157 – 87 . Google Scholar CrossRef Search ADS PubMed 7 Popov AF , Hosseini MT , Zych B , Simon AR , Bahrami T. HeartWare left ventricular assist device implantation through bilateral anterior thoracotomy . Ann Thorac Surg 2012 ; 93 : 674 – 6 . Google Scholar CrossRef Search ADS PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)
Interactive CardioVascular and Thoracic Surgery – Oxford University Press
Published: Jun 3, 2018
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