Role of terminal warm blood cardioplegia in complex congenital heart surgery

Introduction: Myocardial protection is vital to ensure successful open heart surgery. Cardioplegic solution is one method to achieve good myocardial protection. Inevitably, ischemia-reperfusion injury occurs with aortic crossclamping. Histidine-tryptophan-ketoglutarate solution is a frequently used cardioplegia for complex congenital heart surgery. We postulated that addition of terminal warm blood cardioplegia before removal of the aortic crossclamp might improve myocardial protection. Method: A randomized controlled trial was conducted on 109 cyanotic patients aged, 1 to 5 years who underwent complex biventricular repair. They were divided into a control group of 55 patients who had histidine-tryptophan-ketoglutarate only and a treatment group of 54 who had histidine-tryptophan-ketoglutarate with terminal warm blood cardioplegia. Endpoints were clinical parameters, troponin I levels, and caspase-3 as an apoptosis marker. Results: The incidence of low cardiac output syndrome was 34%, with no significant difference between groups (35.2% vs. 33.3%, p = 0.84). The incidence of arrhythmias in our treatment group was lower compared to the control group (36% vs. 12%, p = 0.005). Troponin I and caspase-3 results did not show any significant differences between groups. For cases with Aristotle score ≥ 10, weak expression of caspase-3 in the treatment group post-cardiopulmonary bypass was lower compared to the control group. Conclusion: For complex congenital cardiac surgery, the addition of terminal warm blood cardioplegia does not significantly improve postoperative clinical or metabolic markers.