the effects of st. thomas i and st. thomas ii cardioplegia solutions on coronary sinus lactate in mitral valve surgery; a randomized, double-blinded, clinical trial

Background: cardiac protection strategies in different methods are challenging and crucial, affecting postoperative morbidity and mortality. objectives: we compared the cardio-protective effect of two cardioplegia solutions based on coronary sinus lactate levels. methods: this randomized, double-blinded clinical trial study was performed on 46 candidates for mitral valve replacement between june 2020 and january 2021. the patients were categorized via block randomization method: 1) st. thomas i cardioplegia (n=23) and st. thomas ⅱ cardioplegia (n=23). the coronary sinus lactate levels at different times were measured. in addition, some intra-operative and clinical characteristics after cardiac surgery were recorded. data were analyzed in spss software (version 26.0) using paired and independent t-tests, repeated measure anova, and pearson correlation test at a significance level of p < 0.05. results: in the time trend, the lactate levels in patients with st. thomas ⅱ cardioplegia solution had a significantly lower rate than in st. thomas i (p=0.001). the two groups displayed no statistical difference between the aortic cross-clamp time (p=0.069) and the cpb time (p=0.091). furthermore, the weaning from mechanical ventilation (p=0.078) and icu stay (p=0.061) demonstrated no statistical difference between the study groups. conclusion: based on significantly lower measures of the coronary sinus lactate, the st. thomas ⅱ cardioplegia solution showed a better cardio-protective effect in patients undergoing mitral valve surgery.