Cardiac and neurological assessment of normothermia/warm blood cardioplegia vs hypothermia/cold crystalloid cardioplegia in pediatric cardiac surgery: insight from a prospective randomized trial

Abstract

Objective: Although normothermia and warm blood cardioplegia are widely used in adults, cold crystalloids and hypothermia remain routinely used in pediatric cardiac surgery. The superiority of either technique in both brain and myocardial protection remains controversial. We designed a prospective randomized study to compare both approaches in terms of early myocardial protection and late neurodevelopmental status.

Methods: From 2004 to 2005, 47 patients were randomly assigned to either mild hypothermia associated to cold crystalloid cardioplegia (CCC, 22 patients) or normothermia with intermittent warm blood cardioplegia (IWBC, 25 patients). Intramyocyte adenosine triphosphate (ATP) was measured before, during and after cardioplegic arrest and results between groups were compared. In addition to their cardiac status, early and late neurologic assessment was performed by psychometric evaluation tests.

Results: Intracellular ATP levels were not significantly different between the two groups. However, intragroup comparison revealed different profiles according to myocardial protection: in the normothermia/warm blood cardioplegia group, ATP concentration increased during cardioplegic arrest and returned to initial values afterward (11 nmol mg(-1) vs 21 nmol mg(-1) vs 10 nmol mg(-1), p < 0.001), such changes did not occur in the cold protocol (17 nmol mg(-1) vs 19 nmol mg(-1) vs 14 nmol mg(-1), p = NS). Early neurological outcome was similar in both groups. At late follow-up (mean = 4 years), no significant difference was observed between the two groups.

Conclusions: This study demonstrates that normothermia/IWBC protocols are not deleterious when compared with more conventional approaches. A more physiologic ATP steady state, reflecting the absence of cellular ischemic insult was observed in the IWBC group. Importantly, no significant difference was found between IWBC and CCC groups in terms of early and late neurodevelopmental status.