Protecting the aged heart during cardiac surgery: Single-dose del Nido cardioplegia is superior to multi-dose del Nido cardioplegia in isolated rat hearts

Background: Aged hearts are particularly vulnerable to reperfusion injury. We recently showed that single-dose del Nido cardioplegia was superior to 'standard' multi-dose 4:1 blood cardioplegia in aged rat hearts. This study seeks to determine if multi-dose del Nido cardioplegia offers additional benefits over single-dose del Nido cardioplegia. Methods: Functional recovery after 60 min of cardioplegic arrest was assessed in isolated, working, senescent rat hearts. Single-dose del Nido cardioplegia (n=14) was compared to multi-dose del Nido cardioplegia (n=12) delivered every 20 min. Results: Troponin release during reperfusion was similar in the single (0.263±0.056 ng/ml) and multi-dose groups (0.261±0.055 ng/ml). Although functional recovery was similar early after reperfusion (stroke work 91±6 ml∗mmHg∗g^-1 vs. 91±8 ml∗mmHg∗g^-1 for single- vs. multi-dose), it declined over time in the multi-dose group (71±9 vs. 43±9 ml∗mmHg∗g^-1 at 60 min, p=0.0175) Conclusions: In aged rat hearts, a single-dose del Nido cardioplegia strategy results in superior functional recovery compared to a multi-dose del Nido cardioplegia strategy.