There were 2910 adult patients who received heart transplantation between December 2006 and August 2010, and who had donor echocardiographic data available. We excluded recipients of donor hearts with left ventricular ejection fraction (LVEF) <50% (n = 38), recipients of multiple organ transplants (n = 114) and patients without follow-up after transplant (n = 132). A total of 2626 patients satisfied our inclusion criteria and formed the study population.
The mean age of the recipients was 52 ± 12 years and 2045 (78%) were males. The mean age of the donors was 33 ± 11 years and 1900 (72%) were males. LVH was present in 1150 (44%) allografts. Mild LVH was present in 1002 (38%), moderate in 125 (4.7%) and severe in 23 (0.9%) of allografts. Due to a small number of patients in the latter cohort, recipients of allografts with moderate and severe LVH were analyzed as one group of 148 patients (5.6%). Detailed baseline characteristics of the three groups of interest are shown in . The proportion of patients receiving hearts from donors with LVH remained constant during the study period (p = 0.56 across different study periods).
Baseline characteristics of cardiac transplant donors and recipients
Donors of allografts with LVH were older, were more likely to be of male gender and of a larger body size than donors without LVH. Donors with LVH died more frequently from cerebrovascular accident and required less inotropic support than those without LVH. History of hypertension and diabetes mellitus was present more frequently in donors with LVH. There were no significant differences between the groups in tobacco use, cytomegalovirus (CMV) serologic status and serum creatinine level. In terms of echocardiographic characteristics, donors with moderate-severe LVH had marginally lower ejection fraction than donors with no or mild LVH.
There were no differences in age or gender between the groups. Recipients of allografts with LVH had a larger body size and a higher proportion of diabetes mellitus. There were no differences in history of tobacco use, baseline renal function, CMV serology, history of prior cardiac surgery, mean pulmonary artery pressure or support with a left ventricular assist device (LVAD), extracorporeal membrane oxygenator (ECMO), intra-aortic balloon pump (IABP) or mechanical ventilation. Recipients of allografts with LVH spent shorter time on the waiting list; however there were no significant differences in UNOS status or level of care at the time of transplant (intensive care units: 30%, regular wards: 19% or outpatient: 51%). The donor/recipient ratios for height, weight and body mass index (BMI) were higher for recipients of allografts with LVH and there were no differences between the groups in regards to ischemic time.
During a follow-up of up to 3.3 years (mean follow-up 1.1 ± 0.86 years), 342 deaths (including 12 retransplants) occurred, for a total event rate of 11.8%/year. Recipients of allografts with no LVH, mild LVH and moderate-severe LVH had similar 30-day mortality—4.4%, 5.3% and 4.9%, respectively (p = 0.43) and similar 1-year mortality—12.4%, 13.2% and 13.2%, respectively (p = 0.60). shows Kaplan–Meier survival curves for the three groups. At 3 years after transplant, there was no difference in mortality in recipients of donors with no LVH (21%), mild LVH (26%) and moderate-severe LVH (18%), p = 0.60.
Survival of recipients of allografts with no LVH, mild LVH and moderate or severe LVH
In univariable analyses, donor characteristics associated with all-cause mortality included increasing donor age and history of tobacco use. Donor LVWT (HR 0.95, 95% CI 0.60–1.49, p = 0.83) and the presence of mild (HR 1.07, 95% CI 0.86–1.34, p = 0.52) or moderate-severe LVH (HR 1.03, 95% CI 0.64–1.68, p = 0.89) were not associated with recipient mortality. Recipient predictors of mortality included age >55 years, higher serum creatinine, higher mean pulmonary artery pressure, history of prior cardiac surgery and the need of support with inotropes, LVAD, ECMO or mechanical ventilation (). To adjust for possible confounders, we constructed a multivariable Cox proportional hazards regression model using a number of donor and recipient characteristics. The donor characteristics that were associated with mortality in this multivariable model were donor age and donor history of tobacco use. Additional recipient characteristics associated with post-transplant mortality are listed in . Similar to the results of the univariable analyses, the presence of allograft LVH was not associated with higher risk of mortality in the multivariable model ().
Univariable analysis of donor and recipient factors pre dicting posttransplant survival
Multivariable analysis of donor and recipient factors predicting post-transplant survival
Next we explored whether a combination of specific donor characteristics could have a differential effect on post-transplant survival. Sensitivity analyses for subgroups classified based on the presence of LVH and concomitant history of donor hypertension, or examined by donor gender, were consistent with the main results. However, a subgroup analysis of recipients of allografts with LVH and donor age >55 years showed markedly increased risk of death (mild LVH: HR 6.66, 95% CI 1.43–30.91, p = 0.01; and moderate-severe LVH: HR 6.47, 95% CI 0.58–71.37, p = 0.12). This effect was not found in recipients of allografts with LVH and donor age ≤55 years (mild LVH: HR 1.01, 95% CI 0.81–1.27, p = 0.90; moderate-severe LVH: HR 0.98, 95% CI 0.60–1.62, p = 0.96) (). Kaplan–Meier plots shown in demonstrate differences in survival of recipients of allografts with and without LVH, for donors ≤55 years of age and for donors >55 years of age. Allograft ischemic time also showed interaction with donor LVH as far as effect on mortality after transplant. Recipients of allografts with moderate-severe LVH and allograft ischemic time ≥ 4 h were at increased risk of death (moderate-severe LVH: HR 2.23, 95% CI 1.01–4.93, p = 0.04, mild LVH: HR 1.16, 95% CI 0.77–1.73, p = 0.47)—. The differences in mortality among the different LVH groups stratified by allograft ischemic time are illustrated through a Kaplan–Meier plot in .
Hazard ratios for death in recipients of allografts with no LVH, mild LVH and moderate or severe LVH, in relation to donor age and allograft ischemic time
Effect of donor age on posttransplant survival of recipients of allografts with and without LVH
Effect of ischemic time on posttransplant survival of recipients of allografts with and without LVH