Myocardial preservation methods in isolated minimal invasive mitral valve surgery: Society of Thoracic Surgeons (STS) database outcomes

Objective: Minimal invasive mitral valve surgery (MIMVS) has become a commonly used approach for mitral valve surgery. Several techniques of myocardial preservation were described in patients undergoing MIMVS. We aim to evaluate preservation technique and short term outcomes. Methods: A retrospective analysis of patients who underwent isolated MIMVS and were included in the Society of Thoracic Surgeons (STS) database. Results: The final cohort included 4976 patients. Mean age was 63.1 years (SD, 12.5) and 42.6% were females. Antegrade delivery method (71.3% of the patients) was the most common, follow by antergrade/retrograde (19.9%). Blood, crystalloid solution, and combination of blood-crystalloid were used in 62.4%, 13.2%, and 13.7%, respectively. In multivariate analysis, cardioplegia technique was associated with mortality (P =.011), pleural effusion (P =.045), and length of ICU stay (P <.001). Antegrade-crystalloid (OR, 3.37; 95%CI, 1.70-6.68) and antegrade/retrograde-blood/crystalloid (OR, 3.28; 95%CI, 1.15-9.38) were associated with increased risk for mortality compared with antegrade-blood cardioplegia. Data on postoperative ejection fraction (EF), CPK-MB, and Troponin was available only in 30%, 9%, and 5% of the patients, respectively, and were not included in the analysis. Conclusions: Ante-grade-blood was the most common preservation technique in MIMVS. Ante-grade-crystalloid and ante-grade/retrograde-blood/crystalloid are associated with increased risk for mortality. The results suggest that using crystalloid solutions for cardioplegia should be carefully considered. The STS database as a source for MIMVS outcome analysis is lacking, both in detailed specification of different surgical technique aspects, and in actual data collection of already existing categories.