Minimally invasive versus conventional sternotomy for mitral valve repair

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

Dr Enoch Akowuah (James Cook University Hospital, UK) presented the results of the first multicentre, randomised controlled trial comparing 2 surgical approaches to mitral valve repair [1]. The UK Mini Mitral trial (ISRCTN13930454) screened 1,167 patients and enrolled 330 patients with severe degenerative mitral regurgitation from 10 centres in the UK. The mean age was 67 years, 29% were women, and 40% had atrial fibrillation. They were randomised 1:1 to mitral valve repair by sternotomy or mini-thoracotomy. Surgeons had to have completed at least 50 procedures, and expertise-based randomisation was performed to account for the learning curve. The primary endpoint was a 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.

At 12 weeks, no significant difference was seen between groups for the primary outcome of SF-36v2: mini-mitral valve repair 43.12 ±10.13 versus sternotomy 41.75 ±10.68; mean score difference 0.675 (95% CI -1.89 to 3.26; P=0.61). However, after 6 weeks, physical function had improved in the mini-thoracotomy group but not yet in the sternotomy group. The repair rate was high: 96% in both groups.

Dr Akowuah called the echocardiographic outcomes at 1 year excellent (93% mild MR or less). 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 more numerous at 30 days (difference 1.05; P=0.03) as well as at 90 days (1.03; P=0.03). Quality-of-life outcomes favoured the mini-thoracotomy at all time points. Rates of death, hospitalisation for heart failure, and reintervention on the mitral valve at 1 year were similar and low.

1. Akowuah E, et al. Minimally invasive versus conventional sternotomy for mitral valve repair surgery: an expertise based multicentre randomised controlled trial (UK Mini Mitral). Session 405-08, ACC Scientific Session 2023, 4–6 March, New Orleans, USA.

 

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Posted on 7 June 2023