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Replacement of the aortic valve with a bioprosthesis at the time of continuous flow ventricular assist device implantation for preexisting aortic valve dysfunction Brian Lima, MD, Themistokles Chamogeorgakis, MD, Maria Mountis, MD, and Gonzalo V. Gonzalez-Stawinski, MD Left ventricular assist device (LVAD) implantation has become a mainstay of therapy for advanced heart failure patients who are either ineligible for, or awaiting, cardiac transplantation. Controversy remains over the optimal therapeutic strategy for preexisting aortic valvular dysfunction in these patients at the time of LVAD implant. In patients with moderate to severe aortic regurgitation, surgical approaches are center specific and range from variable leaflet closure techniques to concomitant aortic valve replacement (AVR) with a bioprosthesis. In the present study, we retrospectively analyzed our outcomes in patients who underwent simultaneous AVR and LVAD implantation secondary to antecedent aortic valve pathology. Between January 2004 and June 2010, 144 patients underwent LVAD implantation at a single institution. Of these, 7 patients (4.8%) required concomitant AVR. Five of the 7 patients (71%) survived to hospital discharge and suffered no adverse events in the perioperative period. One-year survival for the discharged patients was 80%, and no prosthetic valve-related adverse events were observed in long-term follow-up. Given our experience, we conclude that bioprosthetic AVR is a plausible alternative for end-stage heart failure patients at the time of LVAD implantation. C ontinuous flow pump technology has revolutionized long-term ventricular assist device therapy. Results from the HeartMate II trial show a considerable improvement in both survival and quality of life in recipients of this technology (1, 2). A proportion of these patients have associated aortic regurgitation (AR) that if left untreated may progress and impact the effectiveness of the pump by limiting forward flow (3). There are several methods of managing AR at the time of left ventricular assist device (LVAD) implantation. Each has its own merits and flaws. Techniques include patch closure of the outflow tract (4), primary aortic cuspal closure with felt strips (5), coaptation stitching of the valve cusps (6), and aortic valve replacement (7). Since our initial experience with the HeartMate II device, we have treated patients with significant AR at the time of HeartMate II implantation by replacing the aortic valve with a bioprosthesis. This report describes the outcomes associated with this approach. METHODS A retrospective review of end-stage heart failure patients who had undergone LVAD implantation with the HeartMate II 454 continuous flow pump with concomitant aortic valve replacement at a single institution was conducted. Etiology of heart failure encountered in this study included ischemic and valvular cardiomyopathies. The latter was defined as end-stage heart failure secondary to untreated aortic or mitral valve disease. Medical records provided demographic and echocardiographic information as well as short- and long-term outcomes. This study was conducted with the approval of the institutional review board of the Cleveland Clinic. All procedures were performed through a full median sternotomy. Aortic valve replacements preceded pump implantations. A pump pocket for the HeartMate II was initially created, and subsequently patients were heparinized and cannulated. With an appropriate activated clotting time (>400 seconds), patients were placed on cardiopulmonary bypass. Myocardial protection was achieved using intermittent cold blood cardioplegia. Aortic valves were replaced through a hockey stick aortotomy. Once the valve was excised, an appropriate-sized bioprosthesis was selected and sutured into place with horizontal mattress pledgeted sutures placed on the ventricular side of the annulus. As described previously, ‘annulus’ was defined as the virtual, circular ring delineated by the nadirs of the semilunar leaflet attachments (8). The aortotomy was closed and the LVAD implanted. In all cases the outflow graft was anastomosed to the ascending aorta distally beyond the suture line employed for the valve replacement. The anticoagulation regimen for patients receiving a HeartMate II device consisted of warfarin, dipyridamole, and aspirin. Early in our experience with the HeartMate II, the target international normalized ratio (INR) ranged from 2.0 to 3.0. More recently, given the current understanding of the physiologic alterations in the coagulation system that occur with this device, we have targeted an INR of 1.7 to 2.5. Immediately From the Department of Cardiac Surgery, Baylor University Medical Center at Dallas, Dallas, Texas (Lima, Chamogeorgakis), and the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio (Mountis, Gonzalez-Stawinski). Dr. Gonzalez-Stawinski is now affiliated with Baylor University Medical Center at Dallas. Corresponding author: Brian Lima, MD, Baylor University Medical Center at Dallas, 3900 Junius Street, Suite 415, Dallas, TX 75246 (e-mail: [email protected]). Proc (Bayl Univ Med Cent) 2015;28(4):454–456 Table. Demographic and outcome data for seven patients receiving simultaneous AVR and LVAD Age (years) Sex 1 56 M DT * VC 6 No 0 2 65 M BTT 4+ VC 159 No 0 VC 711 Intermittently – Patient Indication for LVAD insertion Degree of AR (0–4+) Etiology of heart failure Days with LVAD Bioprosthesis opens at last echocardiogram Thrombus on bioprosthesis 3 57 M DT 0† 4 64 F BTT 2+ IC 421 No ‡ 5 54 M DT 1+ IC 99 No – 6 71 M DT 1–2+ VC 9 No 0 7 59 M DT 2+ IC 391 Intermittently – AR indicates aortic regurgitation; AVR, aortic valve replacement; BTT, bridge-to-transplantation; DT, destination therapy; IC, ischemic cardiomyopathy; LVAD, left ventricular assist device; VC, valvular cardiomyopathy; –, no information available. *Excision of mechanical prosthesis. †Valve stenotic. ‡None on valve but occluding thrombus in subaortic valve area. postoperatively, the speed of the pump was set between 8200 and 8800 revolutions per minute (rpm). This allowed for easier hemodynamic management in the immediate postoperative period because of fluid shifts encountered in the first few days following HeartMate II implantation. The speed typically was adjusted so that there was adequate left ventricular unloading and midline septal alignment, with the aortic valve opening at every third cardiac beat. For patients who underwent aortic valve replacement, we attempted to adjust the pump’s rpm so that the valve opened with every beat. These adjustments were typically conducted with echocardiographic assistance. RESULTS Between January 2004 and June 2010, 144 patients underwent implantation of a HeartMate II at the Cleveland Clinic for the management of end-stage heart disease. Among these, 7 (4.8%) underwent concomitant aortic valve replacement (Table). Indications for HeartMate II support included valvular cardiomyopathy (n = 4) and ischemic cardiomyopathy (n = 3). The end goal for LVAD therapy was destination therapy in five patients and bridge-to-transplantation in two. Indications for aortic valve replacement included four cases of pure AR, one case of mixed AR and aortic stenosis, one case of aortic stenosis, and one case of an in situ mechanical aortic valve prosthesis that needed to be exchanged for a bioprosthesis. Five of seven patients (71%) survived to discharge and suffered no adverse events during their hospitalization. Two perioperative deaths occurred at 6 and 9 days, respectively. These included one patient who underwent a primary aortic valve replacement and HeartMate II implantation. This patient succumbed to severe and refractory vasoplegia, a form of vasodilation not associated with sepsis or neurologic etiologies. Another patient had undergone a redo sternotomy with aortic and mitral valve exchanges from mechanical to bioprosthetic valves, as well as tricuspid valve repair and HeartMate II implantation. This patient died of severe pulmonary dysfunction secondary to acute respiratory distress syndrome and multisystem organ failure. At autopsy, both bioprosthetic valves were well seated with no evidence of thrombus formation. October 2015 At last follow-up, four of the five patients were alive and well. One patient died of sepsis after 99 days of support. Echocardiographic examination of the bioprosthetic valve prior to the patient’s demise suggested that the valve was well seated with no evidence of thrombus or pannus formation. An autopsy was not performed. The remaining patients had no thromboembolic complications at a mean length of support of 395 days (range, 159 to 711). Echocardiographic examination of these patients revealed valves that were well seated with no evidence of thrombosis or pannus formation. Bioprosthetic valves in two destination therapy patients (time on support 391 days and 711 days) intermittently opened on examination. Two other patients underwent transplantation at 159 and 421 days of support. Their echocardiograms showed well-seated bioprosthetic valves that were not opening, with no thrombus or pannus deposited around the valve. Examination of the valves in explanted hearts revealed well-seated valves, without cuspid fusion or cusped thrombi. However, in the patient who was supported 159 days, the left ventricular outflow tract was completely open, while in the one supported for 421 days a fibrous membrane completely occluded the undersurface of the valve. DISCUSSION The optimal management of patients with coexisting AR at the time of continuous flow pump LVAD implantation is not well established. Several options exist, each with its own advantages and disadvantages. Supporters of valve procedures aimed at closing the ventricular outflow with either patch coverage of the valve or leaflet closure suggest that these approaches may theoretically decrease the risk of pump, aortic valve, or subaortic valve thrombus formation by directing flow entirely through the pump (5, 9). Concerns raised by this approach include the mandatory dependence on the pump, which, if it were to malfunction, would potentially be lethal if the ventricle had not recovered to accommodate a high regurgitant backflow. Additionally, these approaches may be applicable only to patients who are transplant candidates, not to patients in whom recovery may be possible. Replacement of the aortic valve with a bioprosthesis at the time of continuous flow ventricular assist device implantation 455 Others suggest treating AR with a coaptation stitch of the leaflets (Park’s stitch) (6). Different from outflow closure techniques, this approach permits partial flow through the root, which may prevent thrombus formation while treating the AR. A second benefit of this technique is that it does not render the patient’s circulation completely LVAD dependent. Issues associated with this approach lie in the potential for valve pathology progression, disruption of the repair causing severe AR, and unknown long-term success (10). Similar to ventricular outflow closure, this technique may not be applicable to those in whom left ventricular recovery is possible. Bioprosthetic valve replacement has the advantage of eliminating valve pathology altogether while not rendering the patient LVAD dependent. If patients are allowed to eject through the valve with some frequency during the cardiac cycle, thrombus formation and leaflet fusion may be prevented. Valve replacement with a bioprosthesis may be a better approach for patients who are recovery candidates, because the LVAD may be explanted without the need to add a valve procedure. The concern of this approach is subvalvular obstruction, which may occur as a result of stagnant blood underneath the bioprosthetic valve (7, 11, 12). Thrombus in this location may embolize during the cardiac cycle or alternatively mature into a fibrous membrane obstructing the outflow tract. The latter event, as seen in one of our patients, may be difficult to detect by standard screening techniques such as echocardiography. Thrombus/pannus formation is not a universal occurrence following valve replacement with a bioprosthesis. Certainly we do not believe that this event is happening in those patients whose valves are intermittently opening while on support, but it may occur, particularly with longer support times. A second issue associated with valve replacement therapy is the added cost incurred when replacing the valve. Furthermore, the time spent replacing the valve may add morbidity to an already complicated procedure. When to replace an incompetent valve may be a challenging decision. The decision has to be balanced not only with the degree of AR but also the objective for which the LVAD is used. For patients awaiting transplantation who have mild to moderate AR and a short waiting time, replacing the valve may not be necessary. Conversely, for patients who are destination therapy candidates who have anything greater than trivial AR (+1 or greater), addressing the valve at the time of LVAD implant seems reasonable. Based on our experience and previously published reports, we believe that a tailored approach to AR at the time of LVAD implantation is warranted. For patients who have a foreseeable short 456 support time, such as bridge-to-transplantation or frail patients, it seems reasonable to treat AR with any one of the coaptation or patch techniques previously described. However, for patients in whom recovery is possible, long-term destination therapy patients, and those with extremely friable aortic valves, aortic valve replacement with a bioprosthetic valve may be a better option. Limitations of this study include the small number of patients, the short follow-up, and the retrospective nature of this report. 1. Rogers JG, Aaronson KD, Boyle AJ, Russell SD, Milano CA, Pagani FD, Edwards BS, Park S, John R, Conte JV, Farrar DJ, Slaughter MS; HeartMate II Investigators. Continuous flow left ventricular assist device improves functional capacity and quality of life of advanced heart failure patients. J Am Coll Cardiol 2010;55(17):1826–1834. 2. Slaughter MS, Rogers JG, Milano CA, Russell SD, Conte JV, Feldman D, Sun B, Tatooles AJ, Delgado RM 3rd, Long JW, Wozniak TC, Ghumman W, Farrar DJ, Frazier OH; HeartMate II Investigators. Advanced heart failure treated with continuous-flow left ventricular assist device. N Engl J Med 2009;361(23):2241–2251. 3. Atkins BZ, Hashmi ZA, Ganapathi AM, Harrison JK, Hughes GC, Rogers JG, Milano CA. Surgical correction of aortic valve insufficiency after left ventricular assist device implantation. J Thorac Cardiovasc Surg 2013;146(5):1247–1252. 4. Rao V, Slater JP, Edwards NM, Naka Y, Oz MC. Surgical management of valvular disease in patients requiring left ventricular assist device support. Ann Thorac Surg 2001;71(5):1448–1453. 5. Adamson RM, Dembitsky WP, Baradarian S, Chammas J, May-Newman K, Chillcott S, Stahovich M, McCalmont V, Ortiz K, Hoagland P, Jaski B. Aortic valve closure associated with HeartMate left ventricular device support: technical considerations and long-term results. J Heart Lung Transplant 2011;30(5):576–582. 6. Park SJ, Liao KK, Segurola R, Madhu KP, Miller LW. Management of aortic insufficiency in patients with left ventricular assist devices: a simple coaptation stitch method (Park’s stitch). J Thorac Cardiovasc Surg 2004;127(1):264–266. 7. Feldman CM, Silver MA, Sobieski MA, Slaughter MS. Management of aortic insufficiency with continuous flow left ventricular assist devices: bioprosthetic valve replacement. J Heart Lung Transplant 2006;25(12):1410– 1412. 8. Charitos EI, Sievers HH. Anatomy of the aortic root: implications for valve-sparing surgery. Ann Cardiothorac Surg 2013;2(1):53–56. 9. Cohn WE, Demirozu ZT, Frazier OH. Surgical closure of left ventricular outflow tract after left ventricular assist device implantation in patients with aortic valve pathology. J Heart Lung Transplant 2011;30(1):59–63. 10. Goda A, Takayama H, Pak SW, Uriel N, Mancini D, Naka Y, Jorde UP. Aortic valve procedures at the time of ventricular assist device placement. Ann Thorac Surg 2011;91(3):750–754. 11. Butany J, Leong SW, Rao V, Borger MA, David TE, Cunningham KS, Daniel L. Early changes in bioprosthetic heart valves following ventricular assist device implantation. Int J Cardiol 2007;117(1):e20–e23. 12. Rose AG, Connelly JH, Park SJ, Frazier OH, Miller LW, Ormaza S. Total left ventricular outflow tract obstruction due to left ventricular assist device-induced sub-aortic thrombosis in 2 patients with aortic valve bioprosthesis. J Heart Lung Transplant 2003;22(5):594–599. Baylor University Medical Center Proceedings Volume 28, Number 4