Key points :
- Mitral valve surgery via sternotomy is associated with significant disadvantages, including an increased risk of bleeding, difficult valve access due to the incision’s location, and a 2-3% risk of wound infections that can result in significant morbidity and mortality.
- Recovery from sternotomy can take up to 3 months, during which patients must significantly limit their activity to reduce the risk of complications, which can prolong recovery and limit their ability to return to usual activities.
- Minimally invasive approaches to mitral valve surgery have been shown to be safe and effective, with lower rates of morbidity and mortality than conventional sternotomy, including in high-risk patients such as the elderly.
- Emerging evidence suggests that minimally invasive surgery may be less costly than conventional sternotomy, with cost savings driven by reduced hospital stay and the need for blood transfusion. The UK Mini Mitral trial aims to assess whether minimally invasive surgery is associated with improvements in physical functioning, a return to usual activities, and cost-effectiveness compared to conventional surgery.
The UK Mini Mitral study is a randomized controlled trial being conducted at multiple centers that compares minimally invasive thoracoscopically-guided right Mini thoracotomy as an intervention to conventional sternotomy as a control in patients undergoing mitral valve repair (MVr).The objective of the trial is to determine whether minimally invasive mitral valve surgery improves physical functioning and return to usual activities in comparison to conventional surgery, as well as assessing the cost-effectiveness of minimally invasive surgery compared to conventional surgery for mitral valve repair. The trial was presented today at ACC 2023 conference by Doctor Enoch Akowuah from James Cook Hospital Marton Road found in the United Kingdom.
The primary outcome is to evaluate physical performance and ability to resume normal activities using the SF-36v2 physical functioning scale, with measurements taken 12 weeks after the initial surgery and a recall period of 4 weeks.
For Mini PF T-scores increase significantly from baseline to 6 weeks and increased throughout the year. For Sternotomy PF T-scores at 6 weeks are not significantly different from baseline, however they become significantly different from 12 weeks and increase further throughout the year. The mean difference in physical function (T-score) from baseline between groups: 0.675 (-1.89,3.26); 0.61.
MR reduced to grade none or mild for 95% of participants in both groups at 12 weeks and 92% at 52 weeks. At 52 weeks 3 Sternotomy participants and 1 Mini participant had severe MR. At 52 weeks, in both groups, left ventricular dimensions and volumes reduced significantly compared to baseline with no significant differences between groups.
In conclusion, minimally invasive thoracoscopically guided right mini thoracotomy for mitral valve repair appears to be a safe and effective alternative to conventional sternotomy, with lower rates of morbidity and mortality, reduced recovery time, and potential cost savings. The UK Mini Mitral trial found that patients who underwent minimally invasive surgery had improved physical functioning and ability to return to normal activities compared to those who underwent conventional surgery, as measured by the SF-36v2 physical functioning scale. Both groups showed significant reductions in mitral regurgitation and left ventricular dimensions and volumes at 52 weeks, with no significant differences between the groups. Overall, the study suggests that minimally invasive surgery may be a preferable option for mitral valve repair.