Donor age is a predictor of early low output after heart transplantation

Background: Using hearts from marginal donors could be related to increased risk of primary graft dysfunction and poor long-term survival. However, factors associated with delayed myocardial recovery after heart transplantation (HTx) remain unknown. We sought to clarify risk factors that predict early low output after HTx, and investigated whether early low output affects mid-term graft dysfunction. Methods: We retrospectively analyzed patients who had undergone HTx at The University of Tokyo Hospital. We defined early low output patients as those whose cardiac index (CI) was <2.2 L/min/m² despite the use of intravenous inotrope at 1 week after HTx. Results: We included 45 consecutive HTx recipients, and classified 11 patients into early low output group, and the others into early preserved output group. We performed univariable logistic analysis and found that donor age was the only significant factor that predicted early low output (odds ratio 1.107, 95% confidence interval 1.034-1.210, p = 0.002). CI of early low output patients gradually increased and it caught up with that of early preserved output patients at 2 weeks after HTx (2.4 ± 0.6 L/min/m² in early low output group vs 2.5 ± 0.5 L/min/m² in early preserved output group, p = 0.684). Plasma B-type natriuretic peptide concentration of early low output patients was higher (1118.5 ± 1250.2 pg/ml vs 526.4 ± 399.5 pg/ml; p = 0.033) at 1 week, 703.6 ± 518.4 pg/ml vs 464.6 ± 509.0 pg/ml (p = 0.033) at 2 weeks, and 387.7 ± 231.9 pg/ml vs 249.4 ± 209.5 pg/ml (p = 0.010) at 4 weeks after HTx, and it came down to that of early preserved output patients at 12 weeks after HTx. Conclusions: Donor age was a predictor of early low output after HTx. We should be careful after HTx from old donors. However, hemodynamic parameters of early low output patients gradually caught up with those of early preserved output patients.