Contemporary Management of Ischemic Mitral Regurgitation at Coronary Artery Bypass Grafting

Should moderate ischemic mitral regurgitation be corrected during coronary artery bypass grafting? a systematic review and meta-analysis

OBJECTIVE

Ischemic mitral regurgitation (IMR) is associated with increased risks of mortality and heart failure. However, the optimal management of moderate IMR remains controversial. We conducted a meta-analysis to appraise whether moderate IMR should be corrected during coronary artery bypass grafting (CABG).

METHODS

We searched PubMed, Embase, and Cochrane databases from its inception up to 15 October 2022 for studies that assessed CABG alone versus CABG with mitral valve (MV) surgery in patients with moderate IMR. The primary outcome was perioperative mortality.

RESULTS

Four randomized controlled trials and three observational studies with propensity-matched data including 1209 patients assessing CABG alone (n = 598) versus CABG with MV surgery (n = 611) were included. Compared to CABG alone, the addition of MV surgery did not significantly increase perioperative mortality (RR, 1.01; 95% CI, 0.52-1.96; p = 0.98) and stroke (RR, 2.14; 95% CI, 0.97-4.72; p = 0.06), whereas a longer cardiopulmonary bypass duration (MD, 54.91; 95% CI, 42.13-67.68; p < 0.01) and an increased incidence of renal failure were observed in the combined-procedure group. At follow-up, the addition of MV surgery was significantly associated with reduced rates of residual MR (RR, 0.26; 95% CI, 0.13-0.51; p < 0.01) and NYHA class III-IV (RR, 0.54; 95% CI, 0.37-0.78; p < 0.01). However, there was no difference in either mid-term mortality (RR, 1.05; 95% CI, 0.65-1.70; p = 0.82) or late mortality (RR, 91; 95% CI, 0.49-1.71; p = 0.78) between the CABG alone group and the combined-procedure group.

CONCLUSIONS

In patients with moderate IMR, the addition of MV surgery to CABG did not increase perioperative mortality. Despite the reduced rates of moderate MR and NYHA class III-IV at follow-up, the addition of MV surgery did not translate in a reduction in mid-term or late mortality.

Outcome of Surgery for Ischemic Mitral Regurgitation Depends on the Type and Timing of the Coronary Revascularization

OBJECTIVE

Long-term outcomes of mitral valve (MV) repair versus MV replacement for ischemic mitral regurgitation (IMR) in patients undergoing either prior (PCR) or concomitant coronary revascularization (CCR) by surgery (CABG) or intervention (PCI) are uncertain.

METHODS AND RESULTS

Of 446 patients receiving MV surgery for IMR between July 2006 and December 2010, 125 patients-87 CCR (69.1%) and 38 PCR (30.9%)-were eligible for inclusion in the study. Survival was higher in CCR versus PCR at long-term follow-up (78.83% vs. 57.9%, p = 0.016). The incidence of MACCE was lower in the CCR compared to PCR at both hospital discharge (34.11% vs. 63.57%, p = 0.003) and at follow-up (34.11% vs. 65.79%, p = 0.0008). Patients receiving CABG or CABG with PCI in PCR had higher mortality risks after MV surgery than CCR patients (X² = 6.029, p = 0.014 and X² = 6.466, p = 0.011, respectively). Whereas in the PCR group, MV repair and MV replacement achieved similar survival probability (X² = 1.551, p = 0.213), MV repair in the CCR group led to improved survival compared to MV replacement (X² = 3.921, p = 0.048). In MV replacement, LAD-CABG improved survival compared to LAD-PCI (U = 15,000.00, Z = -2.373 p = 0.018), and a substantial impact of arterial IMA-LAD grafting was revealed in the Cox-regression analysis (HR 0.334, CI: 0.113-0.989, p = 0.048) as opposed to venous-LAD grafting (HR 0.588, CI: 0.166-2.078, p = 0.410).

CONCLUSION

Early treatment of IMR concomitant to coronary revascularization enhances long-term survival compared to delayed MV surgery after PCR. MV repair is not superior to MV replacement when performed late after coronary revascularization; however, MV repair leads to better survival than MV replacement when performed concomitantly with CABG with arterial LAD revascularization.