Department of Cardiothoracic Surgery, Loma Linda University Medical Center, Loma Linda, Calif.
Department of Medicine (Cardiovascular Medicine), Stanford University Medical Center, Palo Alto, Calif.
J Thorac Cardiovasc Surg. 2019 May;157(5):1865-1875. doi: 10.1016/j.jtcvs.2018.07.115. Epub 2018 Oct 23.
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.
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.
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.
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.
尽管有一些小型单中心报告表明，使用左心室功能障碍的供体心脏可以获得可接受的结果，但目前仍有 19%的潜在供体心脏因左心室功能障碍而未被使用。我们使用大型、多样化的队列研究了左心室功能障碍供体心脏的现代长期生存情况。
我们使用器官共享联合网络数据库，回顾了 2000 年 1 月至 2016 年 3 月期间所有成人心脏移植。比较了基线和术后特征以及 Kaplan-Meier 生存曲线。使用协方差调整的 Cox 回归模型来估计移植后死亡率。为了解决供体射血分数观察到的患者特征的变化，使用 Cox 预测因子作为协变量，在广义多重线性回归模型中构建了倾向评分。在原始 Cox 模型中的所有变量都被包括在内。对于每个受体，生成一个预测的供体射血分数，并将其导出为一个新的平衡评分，用于随后的 Cox 模型。三次样条分析表明，最多可能只有 3 个射血分数类别合适，因此，在一个 Cox 模型中，我们将供体射血分数作为分组变量（使用样条指导的类别）添加，而在另一个模型中作为连续变量添加。
在研究期间，共移植了 31712 个供体心脏。共有 742 个供体心脏因未记录左心室射血分数而被排除，20 个供体心脏因左心室射血分数小于 20%而被排除。左心室射血分数降低的供体心脏来自于更年轻的供体，更常见的是男性供体，并且体重指数低于正常供体心脏。左心室射血分数降低的供体心脏受体更可能需要机械通气。Kaplan-Meier 曲线显示，在 15 年的随访期间，受体的存活率没有显著差异（P=.694，对数秩检验）。Cox 回归分析表明，在调整倾向变化、移植年份和区域后，当作为分类或连续变量分析时，射血分数对死亡率没有统计学意义上的影响。所有组在移植后 1 年左右的左心室射血分数均恢复正常。
精心挑选的左心室射血分数明显降低的供体心脏可以进行移植，其长期生存率与正常供体心脏相当，因此不应仅仅因为左心室射血分数降低而被排除在考虑范围之外。在这项研究中，即使是最受损的供体心脏也能得到功能恢复，这表明在脑死亡的情况下，对左心室功能的研究应该谨慎解读。
