Long-term transplant outcomes of donor hearts with left ventricular dysfunction

Abstract

Objective: Despite small single-center reports demonstrating acceptable outcomes using donor hearts with left ventricular dysfunction, 19% of potential donor hearts are currently unused exclusively because of left ventricular dysfunction. We investigated modern long-term survival of transplanted donor hearts with left ventricular dysfunction using a large, diverse cohort.

Methods: Using the United Network for Organ Sharing database, we reviewed all adult heart transplants between January 2000 and March 2016. Baseline and postoperative characteristics and Kaplan-Meier survival curves were compared. A covariates-adjusted Cox regression model was developed to estimate post-transplant mortality. To address observed variation in patient profile across donor ejection fraction, a propensity score was built using Cox predictors as covariates in a generalized multiple linear regression model. All the variables in the original Cox model were included. For each recipient, a predicted donor ejection fraction was generated and exported as a new balancing score that was used in a subsequent Cox model. Cubic spline analysis suggested that at most 3 and perhaps no ejection fraction categories were appropriate. Therefore, in 1 Cox model we added donor ejection fraction as a grouped variable (using the spline-directed categories) and in the other as a continuous variable.

Results: A total of 31,712 donor hearts were transplanted during the study period. A total of 742 donor hearts were excluded for no recorded left ventricular ejection fraction, and 20 donor hearts were excluded for left ventricular ejection fraction less than 20%. Donor hearts with reduced left ventricular ejection fraction were from younger donors, more commonly male donors, and donors with lower body mass index than normal donor hearts. Recipients of donor hearts with reduced left ventricular ejection fraction were more likely to be on mechanical ventilation. Kaplan-Meier curves revealed no significant differences in recipient survival up to 15 years of follow-up (P = .694 log-rank test). Cox regression analysis showed that after adjustment for propensity variation, transplant year, and region, ejection fraction had no statistically significant impact on mortality when analyzed as a categoric or continuous variable. Left ventricular ejection fraction at approximately 1 year after transplantation was normal for all groups.

Conclusions: Carefully selected donor hearts with even markedly diminished left ventricular ejection fraction can be transplanted with long-term survival equivalent to normal donor hearts and therefore should not be excluded from consideration on the basis of depressed left ventricular ejection fraction alone. Functional recovery of even the most impaired donor hearts in this study suggests that studies of left ventricular function in the setting of brain death should be interpreted cautiously.

Keywords: heart donor evaluation; heart transplantation; ventricular function.