Midterm Echocardiographic Outcomes of Minimally Invasive Mitral Valve Surgery in Patients With Previous Cardiac Surgery

<h2>Abstract</h2><h3>Background</h3> Minimally invasive mitral valve repair (MVr) and mitral valve replacement (MVR) after previous sternotomy are relatively uncommon. This study reports midterm outcomes at a single institution. <h3>Methods</h3> All patients with a history of previous cardiac surgery who underwent minimally invasive MVr and MVR with hypothermic fibrillatory arrest at our institution (Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada) between 2006 and 2024 were included. Follow-up echocardiographic reports were reviewed at 1 year, 1 to 3 years, 3 to 5 years, and 5+ years. Primary outcomes included postoperative complications, all-cause mortality, and rates of grade 3 to 4 mitral regurgitation at follow-up. <h3>Results</h3> A total of 31 patients met the inclusion criteria (25.8% female patients), and their median age was 64 years. A total of 18 patients underwent MVR, and 13 underwent MVr. The most common previous cardiac operations were aortic valve replacement (AVR), coronary artery bypass graft, and MVR. All redo procedures were completed using hypothermic fibrillatory arrest (mean, 23.3 [2.5] °C; median duration, 143.0 minutes [interquartile range, 110.5-175.0 minutes]) for myocardial protection. The 30-day, 5-year, and 10-year all-cause mean mortality rates were 0.0% (0.0%), 12.9% (6.0%), and 25.8% (7.9%), respectively. Patients with previous AVR with or without ascending aortic replacement represented 50% of total deaths. Overall, 4 (12.9%) patients had recurrent grade 3 to 4 mitral regurgitation: 3 died, and 1 had subsequent double-redo MVR. <h3>Conclusions</h3> Our study demonstrates low perioperative mortality rates, thus implying the safety of fibrillatory arrest for myocardial protection in redo minimally invasive MVr and MVR. We also identified that patients with AVR with or without ascending aortic replacement face a higher midterm risk, given the technical difficulty of operating with fibrillatory arrest on the anterolateral portion of the mitral valve when the aortic annulus or root is inflexible.