Regional wall motion abnormalities and scarring in severe functional ischemic mitral regurgitation: A pilot cardiovascular magnetic resonance imaging study

Objectives

To relate cardiovascular magnetic resonance–derived segmental wall motion and myocardial scarring and determine whether they are associated with postoperative mitral regurgitation following coronary artery bypass grafting and annuloplasty for severe functional ischemic mitral regurgitation.

Methods

From January 2001 to October 2006, 29 patients with grade ≥3+ chronic functional ischemic mitral regurgitation were studied using cardiovascular magnetic resonance. Wall motion abnormality was graded for 17 standard left ventricular myocardial segments (0 = none, 1+ = hypokinesis, 2+ = severe hypokinesis, 3+ = akinesis, 4+ = dyskinesis), as was degree of hyperenhancement (scarring). Postoperative mitral regurgitation was assessed longitudinally by 71 transthoracic echocardiograms.

Results

Wall motion abnormalities grade ≥2+ were present in most myocardial segments (median 13). Scar >25% was present in a median of 3 segments, and 44% of those were in the territory of the posterior papillary muscle. Nearly all segments (95%) with >25% scar had ≥2+ wall motion abnormality. Although 90% of patients had no mitral regurgitation at hospital discharge, by 6 months, 34% had mitral regurgitation grade ≥2+. There was little association between wall motion abnormality and recurrence of mitral regurgitation (P > .1). Seventy percent of patients with scar >25% in the posterior papillary muscle region exhibited postoperative mitral regurgitation of grade ≥2+ by 6 months, compared with 15% with score ≤25% (P = .07).

Conclusions

In a pilot study of cardiovascular magnetic resonance imaging in severe functional ischemic mitral regurgitation, severity of posterior papillary muscle region scarring correlated with decreased segmental wall motion and mitral regurgitation early after coronary revascularization and annuloplasty. Routinely assessing scar burden may identify patients for whom annuloplasty alone is insufficient to eliminate mitral regurgitation.

CTSNet classification: 23, 35

Abbreviations and Acronyms: CABG, coronary artery bypass grafting, CMR, cardiac magnetic resonance, LAD, left anterior descending coronary artery, LCx, left circumflex coronary artery, LV, left ventricular, MR, mitral regurgitation, RCA, right coronary artery