Minithoracotomy approach for redo mitral valve surgery: Feasibility, operative outcomes, and comparative analysis of myocardial protection techniques.

OBJECTIVE

Redo mitral valve surgery (MVS) poses technical challenges and high operative risks as the result of adhesions and sternal re-entry. Right minithoracotomy has emerged as an alternative to repeat sternotomy. This study evaluated feasibility and perioperative outcomes of redo MVS through right minithoracotomy and compared 3 different myocardial protection strategies: cardioplegia, ventricular fibrillation (VF), and beating-heart.

METHODS

All patients who underwent redo MVS via right minithoracotomy between 2015 and 2023 were identified from the Mini-Mitral International Registry. The primary end point was in-hospital mortality. Secondary end points included stroke, low cardiac output, bleeding requiring revision, conversion to sternotomy, and major complications. Moreover, 3 myocardial protection strategies were analyzed: cardioplegic arrest (n = 373), VF (n = 105), and beating-heart (n = 24).

RESULTS

A total of 502 patients were included (median age 68 years). Overall in-hospital mortality was 7.6% (4.1% in elective and 24.4% in urgent cases). Conversion to sternotomy occurred in 3%. Stroke rate was 2.8% and reoperation for bleeding was 8.8%. After adjustment, VF was independently associated with a greater risk of low cardiac output (adjusted odds ratio, 3.5; P = .004). Beating-heart surgery was associated with increased in-hospital mortality (adjusted odds ratio, 6.6; P = .02). No significant association was observed between myocardial protection strategy and stroke or major complications.

CONCLUSIONS

Redo MVS via right minithoracotomy is feasible and safe in experienced centers. Cardioplegic arrest was associated with more favorable early outcomes and should be considered the default myocardial protection strategy whenever feasible. No-clamp techniques remain valuable in selected high-risk scenarios but are associated with trade-offs that warrant careful patient selection.