Commentary: Left ventricular assist device complications after heart transplantation: Then and now

Central MessageChanges in heart allocation improved waitlist mortality as designed yet unintended consequences in outcomes resulted. This study identifies issues that the next heart allocation must address.See Article page XXX.“Every system is perfectly designed to get the results it gets.”—Paul Batalden, MD1Patient Safety and Quality HealthcareEditor's notebook: a quotation with a life of its own.https://www.psqh.com/analysis/editor-s-notebook-a-quotation-with-a-life-of-its-own/Date accessed: October 18, 2022Google Scholar Changes in heart allocation improved waitlist mortality as designed yet unintended consequences in outcomes resulted. This study identifies issues that the next heart allocation must address. See Article page XXX. Siems and coauthors2Siems C. Cogswell R. Masotti M. Schultz J. Cowger J. Shaffer A. et al.Impact of left ventricular assist device complications on heart transplant outcomes under the 2018 heart transplant allocation policy.J Thorac Cardiovasc Surg. September 27, 2022; ([Epub ahead of print])Abstract Full Text Full Text PDF Scopus (3) Google Scholar present an important study examining the “Impact of Left Ventricular Assist Device Complications on Heart Transplant Outcomes under the 2018 Heart Transplant Allocation Policy” in this issue of the Journal, illuminating a quixotic but significant observation that patients with left ventricular assist device (LVAD) complications are experiencing greater mortality when undergoing heart transplantation (HT) under the current United Network for Organ Sharing (UNOS) Heart Allocation. The authors, analyzing the Scientific Registry of Transplant Recipients dataset, parsed the patients with LVADs who were transplanted under the current and previous allocation eras into groups with and without LVAD complications. The authors analyzed the outcomes of these transplants at 30 days and 6 months. The authors note the following observations:1.Patients who underwent HT with LVAD complications were on LVAD support longer under the new era (498 days vs 423 days, P < .001).2.Posttransplant survival was greatest in the previous era among those without LVAD complications.3.Patients undergoing HT with LVAD complications in the new era were associated with the greatest posttransplant mortality (status 2 adjusted hazard ratio, 1.87; 95% confidence interval, 1.31-2.67, P < .001, status 3 adjusted hazard ratio, 1.50, 95% confidence interval, 1.11-2.04 P = .009) with 6-month mortality significantly worse for those transplanted with LVAD complications in the new era (10% vs 7.4%, P = .03). Like all important studies, this study raises more questions than it answers. Why does this imbalance exist? From the data presented, the answer is not immediately clear. Differences in heart donors used in transplanting patients with LVADs with complications between the 2 eras, and between patients with LVADs transplanted from status 2 and 3 in the current era are subtle and small: significant differences are noted in ischemic time, with nonsignificant older donors in the new era and in the lower status 3 recipients. Recipient differences? Wait times, duration of LVAD support, and pulmonary artery systolic pressures differ, but again in clinically insignificant amounts. Quixotic clearly. These are the measured data. What we know. There is much we do not and cannot know. Paradoxically, LVADs are better, with patients surviving longer with fewer complications compared with the experience with previous LVADS. MOMENTUM trial data showed excellent 5-year survival driven by improved hemocompatibility.3Mehra M.R. Goldstein D.J. Cleveland J.C. Cowger J.A. Hall S. Salerno C.T. et al.Five-year outcomes in patients with fully magnetically levitated versus axial-flow left ventricular assist devices in the MOMENTUM 3 randomized trial.JAMA. 2022; 328: 1233-1242Crossref PubMed Scopus (30) Google Scholar However, survival is not the end of the story. Patients do still experience driveline infection, heart failure readmissions, stroke, and ventricular tachycardia/fibrillation. Depending on the complication, for waitlisted patients, these complications increase the priority for HT for the patient with an LVAD, but at what cost? With a greater proportion of listed patients with LVADs waiting longer, when complications occur, their new waiting list times are longer, a trend seen in the data analyzed by this paper. Under previous allocation systems, the patient with an LVAD with any complication was elevated to the top tier available for waiting-list patients. Under the current system, the patient with an LVAD with complications is elevated to status 3 generally or status 2 with severe complications. These tiers provide very different access to hearts and to transplantation. These differences likely contribute to greater physiological stress for longer periods of time than patients with LVADs with complications previously experienced. These physiologic changes likely include more renal insufficiency, greater bacterial load/more severe infection, and more heart failure readmissions. Do these constellations of complications lead to a more deconditioned, and more physiologically challenged patients with LVADs than before? Likely. In addition, these patients receive subtly older, more distant organs for a complicated reoperation compared with the same patient with an LVAD under the previous allocation system, with decreased survival noted at 6 months and beyond. This problem is real and needs to be addressed at some point. Lastly, did the early, high-level access of the previous allocation system allow rescue to occur more quickly and successfully than in the current system? What is the solution to this discrepancy? Once the patient with an LVAD experiences a complication, the data suggest additional complications are close behind in a predictable sequence.4Hariri I.M. Dardas T. Kanwar M. Cogswell R. Gosev I. Molina E. et al.Longterm survival on LVAD support: limitations driven by development of device complications and end-organ dysfunction.J Card Fail. 2020; 26: S143-S144Abstract Full Text Full Text PDF Google Scholar It may have been the early, high-level access of the previous allocation system allowed rescue more quickly and successfully than the priority afforded to these patients allow in the current system. These data suggest we should pick sentinel complications for patients with LVADs to detect the first signs of instability. Alternatively, allocation for patients with LVADs could incorporate “time served on LVAD support” for transplant priority. This idea would factor in that not all complications have equal likelihood of occurring at early and late time points. UNOS kidney allocation incorporates dialysis time, not dialysis since listing, to acknowledge the time hazard risk to survival, which may be harder to define for patients with LVADs, but nonetheless real. In the end, we are indebted to the observations of Siems and colleagues2Siems C. Cogswell R. Masotti M. Schultz J. Cowger J. Shaffer A. et al.Impact of left ventricular assist device complications on heart transplant outcomes under the 2018 heart transplant allocation policy.J Thorac Cardiovasc Surg. September 27, 2022; ([Epub ahead of print])Abstract Full Text Full Text PDF Scopus (3) Google Scholar and their insightful analysis of the UNOS/Scientific Registry of Transplant Recipients database in isolating the outcomes in these distinct populations. The authors have shown that patients with LVADs in the current system are not being rescued with equivalent 6-month mortality. Although the cause is unclear, this discrepancy could be remedied by providing higher status and enhanced transplant access at the first sign of complication in LVAD-waitlisted patients. Such a tweak in US heart allocation could, in theory, be implemented without a complete revision of the entire heart allocation system. This change could be test incorporated in the current system and allow dynamic remodeling in a way previous allocation systems did not. This change and others could be then become incorporated in a heart allocation score, when developed and adapted. Impact of left ventricular assist device complications on heart transplant outcomes under the 2018 heart transplant allocation policyThe Journal of Thoracic and Cardiovascular SurgeryPreviewThe study objective was to determine the impact of left ventricular assist device complications on post–heart transplant survival before and after the 2018 US heart transplant allocation policy change. Full-Text PDF