Do we correctly calculate doses of cardioplegia during aortic valve replacement procedures? A preliminary report

Introduction: Intraoperative myocardial protection during aortic valve replacement (AVR) for aortic stenosis (AS) is of paramount importance for outcomes. The dose of cardioplegia is usually calculated with reference to body mass.Aim: To assess whether such a strategy should be applied to all AS patients undergoing AVR. Material and methods: The study included 94 patients who underwent elective isolated AVR in cardiopulmonary bypass with cold cardioplegic arrest, with a mean age of 65.4 +/- 7.8 years. They were divided into two subgroup: A with an infusion of high (above median) and subgroup B with a low (below median) volume of cardioplegia indexed for left ventricular mass (LVM). Their doses were referred to the maximal postoperative release of cardiac troponin I (cTnI max). Eventually, it was examined whether the extent of intraoperative myocardial injury translated into long-term survival stratified according to the Kaplan-Meier method.Results: The mean volume of cardioplegia was 1381 +/- 279 ml (4.9 +/- 1.6 ml/g of LV myocardium). cTnI max was much higher in group A than in group B (medians: 14.918 vs. 9.876 mu g/l; p = 0.005). Moreover, a negative correlation between the index cardioplegia volume and cTnI max (r = 0.345) was noted. The five-year probability of survival in subgroup A (95.7%) was significantly better than that in subgroup B individuals (82.6%, p = 0.044).Conclusions: Calculating cardioplegic doses during AVR solely based on body mass may be suboptimal and have a significant impact on postoperative outcomes.