One-Year Outcomes Following Heart Transplantation Under the New Donor Heart Allocation System in the United States.

Abstract

HomeCirculation: Heart FailureVol. 14, No. 2One-Year Outcomes Following Heart Transplantation Under the New Donor Heart Allocation System in the United States Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessLetterPDF/EPUBOne-Year Outcomes Following Heart Transplantation Under the New Donor Heart Allocation System in the United States Taylor Nordan, BS, Andre C. Critsinelis, MD, Frederick Y. Chen, MD, PhD, Navin K. Kapur, MD, Katherine L. Thayer, MPH, Gregory S. Couper, MD and Masashi Kawabori, MD Taylor NordanTaylor Nordan https://orcid.org/0000-0002-1581-8214 Division of Cardiac Surgery (T.N., F.Y.C., G.S.C., M.K.), Tufts Medical Center, Boston, MA. Search for more papers by this author , Andre C. CritsinelisAndre C. Critsinelis Department of Surgery, Mount Sinai Medical Center, Miami, FL (A.C.C.). Search for more papers by this author , Frederick Y. ChenFrederick Y. Chen Division of Cardiac Surgery (T.N., F.Y.C., G.S.C., M.K.), Tufts Medical Center, Boston, MA. Search for more papers by this author , Navin K. KapurNavin K. Kapur https://orcid.org/0000-0002-8302-6796 Division of Cardiology (N.K.K., K.L.T.), Tufts Medical Center, Boston, MA. Search for more papers by this author , Katherine L. ThayerKatherine L. Thayer https://orcid.org/0000-0002-0848-5853 Division of Cardiology (N.K.K., K.L.T.), Tufts Medical Center, Boston, MA. Search for more papers by this author , Gregory S. CouperGregory S. Couper Division of Cardiac Surgery (T.N., F.Y.C., G.S.C., M.K.), Tufts Medical Center, Boston, MA. Search for more papers by this author and Masashi KawaboriMasashi Kawabori Correspondence to: Masashi Kawabori, MD, Division of Cardiac Surgery, Tufts Medical Center, 800 Washington St, Boston, MA, 02111. Email E-mail Address: [email protected] https://orcid.org/0000-0002-3580-5664 Division of Cardiac Surgery (T.N., F.Y.C., G.S.C., M.K.), Tufts Medical Center, Boston, MA. Search for more papers by this author Originally published28 Jan 2021https://doi.org/10.1161/CIRCHEARTFAILURE.120.007754Circulation: Heart Failure. 2021;14:e007754Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: January 28, 2021: Ahead of Print Survival following heart transplantation under the new donor heart allocation system implemented on October 18, 2018, has been under scrupulous investigation. Early reports of 180-day freedom from death or retransplantation have produced mixed results. Cogswell et al1 initially reported 180-day freedom from death or retransplantation of 77.9% (hazard ratio [HR], 2.1 [95% CI, 1.5–3.0], P<0.001) under the new system compared with 93.4% under the old system.1 However, Hanff et al2 and Jawitz et al3 have recently reported comparable 180-day survival under the new system compared with the old system.2,3 Although these early reports provide valuable information surrounding survival under the new system, longer-term survival remains unknown. We report 1-year freedom from death or retransplantation for patients listed and transplanted under the new system. In addition, we report 1-year survival free from death or retransplantation in recipients bridged with temporary mechanical circulatory support (MCS) and waitlist outcomes for candidates listed with temporary MCS.Since data from the United Network for Organ Sharing database are publicly available and deidentified, this study was deemed exempt from Institutional Review Board review. Requests to access the data set from qualified researchers trained in human subject confidentiality protocols may be sent to United Network for Organ Sharing. Patients ≥18 years old at the time of listing who received a first-time single-organ heart transplant were considered for inclusion. Patients listed and transplanted from October 18, 2015, through October 17, 2018, were compared with those listed and transplanted from October 18, 2018, through May 12, 2019.1–3 The data set used in this analysis contains follow-up current through June 12, 2020. Patients listed before October 18, 2018, who underwent transplantation after October 18, 2018, were excluded from the analysis. Methodology for identifying MCS has been previously described by Cogswell et al.1 The primary end point was defined as death or retransplantation. The secondary end point included removal from the waitlist due to death or worsening clinical condition. Stata version 16 (Stata Corp, College Station, TX) was used for all statistical analyses. Univariate analysis of the association between allocation system and post-transplant freedom from death or retransplantation was assessed using the Kaplan-Meier method. Multivariable Cox proportional hazards analysis was used to quantify the association between allocation system change and event-free post-transplant survival after adjustment for key covariates. Covariates were determined a priori based on prior literature1–3 and included: recipient age, recipient sex, prior cardiac surgery, heart failure cause, ischemic time, days on the waitlist, donor age, presence of a durable left ventricular assist device, and sex mismatch, defined as a female donor and male recipient. Restricted cubic splines with 3 prespecified knots, based on the distribution of each variable, were used to model the linearity of continuous variables with the hazard of the outcome. Propensity-score matching sensitivity analysis, with 1:1 matching on previously used variables,3 was performed. Fine-Gray competing risks analysis was performed to analyze death or clinical deterioration on the waitlist among candidates listed with temporary MCS.Of 836 recipients included under the new system, median follow-up time was 362 days. MCS bridging changed from the old system to the new system as follows, displayed as absolute percentage differences: venoarterial extracorporeal membrane oxygenation: +5.1% (P<0.001), intraaortic balloon pump: +27.1% (P<0.001), temporary ventricular assist device: +4.9% (P<0.001) and durable left ventricular assist device: −21.3% (P<0.001). Univariate analysis demonstrates similar 1-year survival under the new system compared with the old system (HR, 1.03 [95% CI, 0.80–1.33], log-rank P=0.807; Figure [A]). Multivariable Cox proportional hazards models also demonstrate no significant difference in 1-year morbidity and mortality under the new system (adjusted HR, 1.04 [95% CI, 0.79–1.36], P=0.789). Propensity-score matching analysis identified 725 unique pairs and demonstrated similar 1-year survival under the new system compared with the old system (log-rank P=0.182; Figure [B]). Univariate analysis of recipients bridged with temporary MCS demonstrated no significant difference in 1-year survival under the new system (HR, 0.95 [95% CI, 0.64–1.43], log-rank P=0.806; Figure [C]). Adjustment for covariates did not yield any significant difference (HR, 0.89 [95% CI, 0.57–1.39], P=0.608). The new system did, however, provide significant protection from death or clinical deterioration on the waitlist among candidates listed with temporary MCS (HR, 0.53 [95% CI, 0.36–0.76], P=0.001; Figure [D]).Download figureDownload PowerPointFigure. Outcomes comparison between new vs old allocation systems.A, Freedom from death or retransplantation 1 year after transplantation under new vs old allocation systems. B, Freedom from death or retransplantation 1 year after transplantation under new vs old allocation systems using propensity-score matched cohorts. C, Freedom from death or retransplantation 1 year after transplantation under new vs old allocation systems in recipients bridged with temporary mechanical circulatory support (MCS). D, Waitlist removal due to death or worsening clinical condition in candidates listed with temporary MCS. Adjusted hazard ratio estimates are displayed in A and C.Before the allocation system change on October 18, 2018, many transplant centers were worried that increased use of temporary MCS bridging would lead to significant increases in postoperative morbidity and mortality. This fear was validated by analyses of temporary MCS bridging under prior allocation systems, which demonstrated excessive post-transplant mortality among recipients bridged with nonsurgical temporary MCS.4,5 The data we present indicate that longer-term survival may be comparable under the new system compared with the old system. Further, recipients listed with temporary MCS are significantly less likely to experience death or clinical deterioration on the waitlist under the new system. Our results represent transplants that occurred over 7 months under the new system. Although follow-up for this cohort may be incompletely documented although follow-up through June 12, 2020, was used, significant bias from informative censoring is unlikely.Nonstandard Abbreviations and AcronymsHRhazard ratioMCSmechanical circulatory supportAcknowledgmentsThe data reported here have been supplied by the United Network for Organ Sharing as the contractor for the Organ Procurement and Transplantation Network. The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy of or interpretation by the OPTN or the US Government.Sources of FundingNone.Disclosures None.FootnotesThis manuscript was sent to Edo Y. Birati, MD, Guest Editor, for review by expert referees, editorial decision, and final disposition.For Sources of Funding and Disclosures, see page 257.Correspondence to: Masashi Kawabori, MD, Division of Cardiac Surgery, Tufts Medical Center, 800 Washington St, Boston, MA, 02111. Email kawabori.[email protected]com