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

Cardiac protection strategies in different methods are challenging and crucial, affecting postoperative morbidity and mortality.

We compared the cardio-protective effect of two cardioplegia solutions based on coronary sinus lactate levels.

 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

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.

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.

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.