The best surgical approach for mitral valve repair is subject to wide debate. Findings from the randomized UK Mini Mitral trial showed similar improvement in physical activity, surgical outcomes and quality of life in patients undergoing minimally invasive and conventional surgical techniques for mitral valve repair.

The results of the UK Mini Mitral trial (ISRCTN13930454) were presented at the 2023 American College of Cardiology annual meeting by Dr. Enoch Akowuah.1 He noted that this is the first multicenter, randomized controlled trial comparing two surgical approaches to mitral valve repair. Of 1,167 screened patients, 330 were included with severe degenerative mitral regurgitation (DMR) from 10 centers in the UK. The mean age was 67, 29% were women, and 40% had atrial fibrillation. They were randomized 1:1 to mitral valve repair by sternotomy or mini-thoracotomy. Surgeons had to have completed at least 50 procedures. Expertise-based randomization was performed to account for the learning curve.

The primary endpoint was change in physical functioning and post-surgery return to daily activities, measured by the change in score on the 36-item short form (SF-36v2) physical functioning scale, from baseline to 12 weeks post-procedure. This was not significantly different between groups: mini-MVR, 43.12 ±10.13 versus sternotomy, 41.75 ±10.68; mean score difference, 0.675 (95% CI, -1.89-3.26; P=0.61). However, physical function had improved in the mini-thoracotomy group but not yet in the sternotomy group after 6 weeks. The repair rate was high: 96% in both groups.

Echography outcomes at 1 year were excellent (93% mild MR or less), said Dr. Akowuah. The length of hospital stay was shorter in the mini-thoracotomy group than in the sternotomy group, with a median of 5 versus 6 days. Early discharge was more than twice as likely in the mini-thoracotomy group. In this group, days alive and out of hospital were also higher at 30 days (difference, 1.05; P=0.03) as well as at 90 days (1.03; P=0.03). QOL outcomes favored the mini-thoracotomy at all timepoints. Rates of death, hospitalization for heart failure, and reintervention on the mitral valve at 1 year were similar and low.

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