Ischemic mitral regurgitation (MR) is common and associated with poor outcomes among patients undergoing bypass surgery.  However, it remains unknown whether repair of ischemic MR concurrent to CABG leads to better patient outcomes.  To address this important clinical question, this multi-center study randomly assigned 301 patients with moderate ischemic MR to CABG alone or CABG plus mitral valve repair.  The primary end-point was the echocardiographic parameter of left ventricular end-systolic volume index (LVESVI) at 1-year, which is a measure of left ventricular remodeling and is a known predictor of poor outcomes. Secondary end-points included major adverse cardiac or cerebrovascular events and functional assessments using the Minnesota heart failure questionnaire.  At 1-year post-operation, there were no statistically significant differences in LVESVI or mean change in LVESI from baseline, quality of life indices, or mortality outcomes.  The addition of MV repair to CABG did result in a higher rate of serious neurological events that included stroke, transient ischemic attack, and metabolic encephalopathy (3.1% vs 9.6%, P=0.03). Concurrent MV repair was also associated with lower levels of moderate to severe MR at 1 year (11.2% vs. 31.0%, P<0.001).

Conclusions

Among patients undergoing CABG, the addition of surgical repair for moderate ischemic regurgitation did not improve LVESI, quality of life, or mortality outcomes.  Although rates of moderate and severe MR at 1-year were reduced with surgical repair, this potential benefit appears offset by increased short term risk of adverse neurologic events.

Summarized by Hussain Contractor and Steven M. Bradley

• Smith PK, Puskas JD, Ascheim DD, Voisine P, Gelijns AC, Moskowitz AJ, Hung JW, Parides MK, Ailawadi G, Perrault LP, Acker MA, Argenziano M, Thourani V, Gammie JS, Miller MA, Pagé P, Overbey JR, Bagiella E, Dagenais F, Blackstone EH, Kron IL, Goldstein DJ, Rose EA, Moquete EG, Jeffries N, Gardner TJ, O’Gara PT, Alexander JH and Michler RE. Surgical treatment of moderate ischemic mitral regurgitation. N Engl J Med. 2014 Dec 4;371(23):2178-88.