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Oct 17, 2013 - Bryan G. Maxwella,*, Jim K. Wonga, Ahmad Y. Sheikhb, Peter H.U. Leeb ... +1-650-7258544; e-mail: bryanmaxwell@gmail.com (B.G. Maxwell). ..... [9] Davies RR, Sorabella RA, Yang J, Mosca RS, Chen JM, Quaegebeur JM.
ORIGINAL ARTICLE

European Journal of Cardio-Thoracic Surgery 45 (2014) 842–846 doi:10.1093/ejcts/ezt498 Advance Access publication 17 October 2013

Heart transplantation with or without prior mechanical circulatory support in adults with congenital heart disease† Bryan G. Maxwella,*, Jim K. Wonga, Ahmad Y. Sheikhb, Peter H.U. Leeb and Robert L. Lobatoa a b

Department of Anesthesia, Stanford University School of Medicine, Stanford, CA, USA Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, CA, USA

* Corresponding author. Department of Anesthesiology, Stanford University Medical Center, 300 Pasteur Drive, H3586, Stanford, CA 94305-5640, USA. Tel: +1-650-7237377; fax: +1-650-7258544; e-mail: [email protected] (B.G. Maxwell). Received 6 May 2013; received in revised form 5 August 2013; accepted 3 September 2013

Abstract OBJECTIVES: Recent analyses establish that heart transplantation is increasing among adults with congenital heart disease (ACHD), but the effects of pretransplant mechanical circulatory support (MCS) on perioperative and post-transplant outcomes have not been examined in the ACHD population. METHODS: Scientific Registry of Transplant Recipients data on all adult heart transplants from September 1987 to September 2012 (n = 47 160) were classified based on primary diagnosis codes as CHD or non-CHD and MCS or non-MCS. Demographic, procedural, outcome and survival variables were compared between MCS and non-MCS ACHD patient groups. RESULTS: MCS was used in 83 (6.8%) ACHD patients compared with 8625 (18.8%) patients without CHD (P < 0.001). MCS as a fraction of ACHD transplants increased over time (P = 0.002). MCS patients spent more time on the wait list, had a higher baseline serum creatinine and were more likely to be male, status 1A, hospitalized, in the ICU and/or on a ventilator prior to transplant. However, MCS patients experienced equivalent short-term survival (30-day mortality = 10.8% in MCS vs 13.5% in non-MCS, P = 0.62) and overall survival by Kaplan–Meier analysis (P = 0.57). MCS patients had a longer post-transplant length of stay and were more likely to be transfused, but otherwise had no significant differences in adverse outcomes. CONCLUSIONS: MCS is less commonly used in adult CHD patients compared with all patients undergoing heart transplant, but has been increasing over time. Within the ACHD population, patients with MCS have a higher risk profile, but except for increased transfusion rate and longer length of stay, do not experience less favourable post-transplant outcomes. Keywords: Mechanical circulatory support • Ventricular assist device • Congenital heart disease • Adult congenital heart disease • Heart transplantation

INTRODUCTION Improved survival to adulthood has resulted in dramatic increases in the prevalence of adult congenital heart disease (ACHD), and adults with congenital heart disease (CHD) now outnumber children [1]. Late sequelae of unoperated, palliated or repaired CHD include valvular dysfunction, significant arrhythmias and ventricular dysfunction. After other medical and interventional options are exhausted, many patients are referred for heart transplantation [2]. Mechanical circulatory support (MCS) as a bridge to transplant has become an increasingly utilized pathway for symptomatic patients awaiting orthotopic heart transplant (OHT), but may have been underutilized in the ACHD population [3]. Prior analyses of OHT in ACHD are dated [4] or have not specifically analysed the role of MCS in outcomes [5]. We sought to perform a contemporary analysis of outcomes of OHT in ACHD patients, with a particular focus on comparing † Presented in part at the 35th Annual Meeting of the Society of Cardiovascular Anesthesiologists, Miami, FL, USA, 6–10 April 2013.

outcomes in patients bridged with MCS versus outcomes in patients not bridged with MCS.

MATERIALS AND METHODS The Stanford University Institutional Review Board granted an exemption from review because this analysis uses deidentified data. Transplantation and post-transplant survival data were obtained using comprehensive datasets from the Organ Procurement and Transplantation Network (OPTN) through the Scientific Registry of Transplant Recipients (SRTR). The SRTR data system includes data on all donor, wait-listed candidates and transplant recipients from all transplant centres in the USA, submitted by members of the OPTN under the oversight of the Health Resources and Services Administration, US Department of Health and Human Services. Datasets from the OPTN and SRTR were supplied by the Minneapolis Medical Research Foundation pursuant to HSRA contract number HHSH250201000018C. The authors alone were

© The Author 2013. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

B.G. Maxwell et al. / European Journal of Cardio-Thoracic Surgery

Figure 1: The proportion of ACHD transplants relative to all adult transplants increased over the study period.

Figure 2: The proportion of ACHD transplant patients supported with MCS relative to all ACHD increased over the study period.

Statistical analysis Baseline characteristics and outcome variables were compared using Fisher’s exact test or the Wilcoxon test, as appropriate. Survival analysis was performed using Kaplan–Meier curves and the log-rank test for inter-group survival comparison. Trends over time were examined using a Mann–Kendall test for trend (a nonparametric test to determine the presence and direction of a trend over time [7]). Unless otherwise specified, all tests were twotailed with a predetermined alpha for statistical significance of 0.05. Analyses were performed using Microsoft Excel (version 2010, Microsoft Corporation, Redmond, WA, USA) and SAS 9.3 (SAS Institute, Cary, NC, USA).

RESULTS During the study period, of the 54 102 patients who underwent heart transplant, 47 160 (87.2%) were adults. Of these, 1213 (2.6%) had a primary diagnosis of CHD. The proportion of ACHD transplants relative to all adult transplants increased over time (Fig. 1, test for trend P < 0.001). MCS was used in 83 patients (6.8%). For comparison purposes, MCS was used in 8625 (19.3%) of 44 734 adults without CHD, and in 126 (3.7%) of 3426 children with CHD. The proportion of ACHD transplant patients supported with MCS as a fraction of all ACHD transplants increased over time (Fig. 2, test for trend P < 0.001). Thirty-day mortality by year of

Figure 3: Thirty-day mortality rate by year of transplant for all ACHD patients decreased over the study period.

transplant among all ACHD patients decreased over the study period (Fig. 3, test for trend P < 0.001). The characteristics of the MCS and non-MCS groups of ACHD patients are given in Table 1. Patients in the MCS group were more likely to be male, have had a prior sternotomy and on average had a higher serum creatinine and pulmonary capillary wedge pressure at listing. MCS patients spent fewer days on the waiting list, but were more likely to be in the hospital, in the ICU, on a ventilator or status 1A at the time of transplant. Within the MCS group, 67 (80.7%) were supported with a left ventricular assist device, 5 (6.0%) were supported with a right ventricular assist device, 6 (7.2%) were supported with both left and right ventricular assist devices and 5 (6.0%) were supported with the total

TX & MCS

responsible for reporting and interpreting these data; the views expressed herein are those of the authors and not necessarily those of the US Government. All recipients of OHT between 30 September 1987 and 1 September 2012 were included for analysis. Heart–lung transplants were excluded. Follow-up information was available through 2 September 2012. The primary population of interest included adults (defined at a recipient age of 18 years or greater at the time of transplant), but paediatric recipient statistics were calculated for comparison. Adult heart transplant recipients were classified based on primary diagnosis codes and the presence of prior congenital heart surgery as CHD or non-CHD. The use of pretransplant MCS was recorded from data variables recorded for the presence or absence of MCS at the time of transplant as well as descriptive variables recording the device or devices used, and each patient was classified as MCS or non-MCS. Short-term circulatory support in the form of intra-aortic balloon pump and extracorporeal membrane oxygenation were not included as MCS. Descriptive, perioperative and outcome variables were compared between the MCS and non-MCS groups. After initial analysis resulted in a finding of no difference in adverse outcomes or survival, a post hoc subgroup analysis was performed to explore whether this finding was confounded by the fact that the MCS group was sicker at baseline. We compared the MCS group (n = 83) with a subset of non-MCS patients (n = 83) matched on the baseline variables that had proved significantly different between the original groups. Using a previously described SAS greedy matching macro [6], 1:1 caliper matching was performed on sex, body surface area (±0.2 m2), serum creatinine (±0.2 md/dl), prior sternotomy, transplant year, pretransplant medical status (not hospitalized; hospitalized, not in intensive care unit (ICU); or hospitalized, in ICU) and presence of OPTN status 1A to create the comparison group.

843

844

B.G. Maxwell et al. / European Journal of Cardio-Thoracic Surgery

artificial heart. Of left ventricular assist devices used, 33 (49.2%) were pulsatile and 34 (50.7%) were continuous flow. Outcomes of transplantation in the MCS and non-MCS groups are given in Table 2. While the MCS group was more likely to receive a transfusion and had a longer average length of stay, other postoperative complications were not different between Table 1: Characteristics of MCS and non-MCS groups

Age Male Body surface area Body mass index Cardiac output at listing (l/min) Cardiac output (l/min) Cardiac index (l/min m2) Serum creatinine (mg/dl) PVRI (Woods units m2) PA systolic (mmHg) PA diastolic (mmHg) PA mean (mmHg) PCWP (mmHg) Total bilirubin (mg/dl) Diabetes Retransplant Prior sternotomy Pretransplant status Not hospitalized On inotropes Hospitalized, not in ICU In ICU On ventilator Admitted in 90 days prior to transplant admission Days on waiting list Days admitted prior to transplant Status 1A

Non-MCS, n = 1130

MCS, n = 83 P-value

33.8 ± 12.7 704 (62.3) 1.8 ± 0.3 24.2 ± 14.7 4.2 ± 1.6 4.4 ± 1.6 2.4 ± 0.9 1.3 ± 0.9 4.1 ± 4.3 37.8 ± 16.1 18.6 ± 8.8 25.7 ± 10.8 17.5 ± 7.8 1.3 ± 2.0 48 (5.3) 94 (8.4) 381 (33.7)

35.1 ± 13.9 67.0 (80.7) 1.9 ± 0.3 25.8 ± 5.6 4.2 ± 1.6 4.9 ± 2.0 2.5 ± 1.0 1.7 ± 0.9 4.0 ± 2.6 43.7 ± 15.4 23.1 ± 9.6 30.4 ± 10.9 20.6 ± 9.3 1.4 ± 1.4 4 (4.9) 5 (6.0) 73 (88.0)

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