Coronary artery bypass grafting versus concomitant mitral valve annuloplasty in moderate ischemic mitral regurgitation: 4-year follow-up

Comparison of Coronary Artery Bypass Grafting Combined With Mitral Valve Repair Versus Coronary Artery Bypass Grafting Alone in Patients With Moderate Ischemic Mitral Regurgitation: A Meta-Analysis

The aim of this meta-analysis was to compare clinical outcomes between those who underwent coronary artery bypass grafting (CABG) alone and CABG with mitral valve repair (MVR) in patients with moderate ischemic mitral regurgitation. The present study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two authors performed a comprehensive search of international databases, including PubMed, EMBASE, and the Cochrane Library, for relevant studies published from inception to March 1, 2023. The search was performed again before the submission of the manuscript on March 20, 2023. Primary outcomes assessed in the present meta-analysis included early mortality and long-term mortality. Secondary outcomes assessed in the present meta-analysis included change in New York Heart Association (NYHA) score from baseline, change in ejection fraction (EF) from baseline (%), and major cardiovascular events (MACE). A total of 13 studies were included in the present meta-analysis. Out of 13 included studies, four were randomized control trials (RCTs) and nine were retrospective cohort studies. The pooled analysis showed that early mortality was significantly lower in patients in the CABG group compared to the CABG+MVR group (risk ratio [RR]: 0.47, 95% confidence interval [CI]: 0.31, 0.70). Long-term mortality was also lower in patients who underwent CABG compared to patients in the CABG+MVR group. However, the difference was statistically insignificant (RR: 0.88, 95% CI: 0.77, 1.02). No significant differences were reported in the EF score between patients who underwent CABG and patients who underwent CABG plus MVR (mean difference [MD]: 0.40, 95% CI: -1.90, 2.69). NYHA score was significantly lower in patients in the CABG+repair group compared to the CABG alone group (MD: 0.39, 95% CI: 0.06, 0.72). In conclusion, our meta-analysis suggests that concomitant MVR during CABG may not improve clinical outcomes in patients with moderate ischemic mitral regurgitation. Further clinical trials are needed to investigate this intervention in more detail.

Should the mitral valve be repaired for moderate ischemic mitral regurgitation at the time of revascularization surgery?

BACKGROUND

Ischemic mitral regurgitation (IMR) is associated with increased mortality and recurrent congestive heart failure following coronary artery bypass graft (CABG) surgery. While mitral surgery should be undertaken for severe MR during CABG, the treatment of moderate IMR remains controversial. We conducted a meta-analysis to determine the outcomes of CABG alone and combine with mitral valve repair (MVr) in moderate IMR.

METHODS

A literature search was conducted by Pubmed, Ovid, and Embase, which included 643 articles. Eleven studies (seven observational studies and four randomized controlled trials) with a total of 1406 patients were included (CABG alone = 864 and CABG plus MVr = 542).

RESULTS

There was no difference in operative mortality (odds ratio 1.56, 95% confidence interval [CI] 0.92-2.71) or long-term survival at 1 or 5 years (hazard ratio 0.98, 95%CI 0.71-1.35, P = 0.49) between the two groups, and little evidence of heterogeneity was found in the studies (I²  = 0.0, P = 0.562). There was significantly greater improvement in MR grade (weighted mean difference [WMD] -1.15, 95%CI -1.67 to -0.064, P = < 0.001) and left ventricular systolic diameter (WMD -3.02, 95%CI -4.85 to -1.18, P = 0.001) following CABG and MVr compared to CABG alone. No difference in postoperative functional class or ejection fraction was found.

CONCLUSIONS

Our results show that in the presence of moderate IMR, adding MVr to revascularization reduces MR grade on follow-up echocardiography and promotes ventricular remodeling, with no improvement in long-term survival or functional class.