Cardiovascular Magnetic Resonance Assessment of Myocardial Scarring Predicts Recurrence of Functional Ischemic Mitral Regurgitation after Anuloplasty
Tomislav Mihaljevic, Michael Flynn, Ronan Curtin, Edward R. Nowicki, Jeevanantham Rajeswaran, Scott D. Flamm, Eugene H. Blackstone; Cleveland Clinic, Cleveland, OH
Comment on this Abstract
Objective: The aims of this pilot study were to investigate the relation of cardiovascular magnetic resonance (CMR)-derived segmental wall motion and myocardial scarring to recurrence of mitral regurgitation (MR) following CABG and anuloplasty for ischemic MR.
Methods: From January 2001 to November 2006, 29 patients with ≥3+ ischemic MR had preoperative CMR prior to CABG and anuloplasty. Wall motion abnormality was graded for 17 standard myocardial segments (0=none, 1+=hypokinesis, 2+=severe hypokinesis, 3+=akinesis, 4+=dyskinesis). Within each of these segments, degree of hyperenhancement, interpreted as scar, was graded as 0=0%, 1=1-25%, 2=26-50%, 3=51-75%, 4=76-100%. Postoperative recurrence of MR was assessed by 71 transthoracic echocardiograms and graded 0-4+.
Results: Left ventricular ejection fraction ranged from 10-45% (mean 22±8.4%). Wall motion abnormalities grade ≥2+ were present in the majority of myocardial segments (median 13 of 17 segments). Scar >25% was present in a median of 3 segments, but in 44% of those in the territory of the posteromedial papillary muscle. Nearly all segments (95%) with >25% scar had ≥2+ wall motion abnormality. Although 90% of patients had no MR at hospital discharge, by 6 months, 30% had recurrent MR ≥2+. There was little association between wall motion abnormality and recurrence of MR (P>.1). However, in the territory of the posteromedial papillary muscle, 70% of patients with scar >25% had recurrent MR of ≥2+ by 6 months, compared with 15% of those with score ≤25% (P=.05; Figure.).
Conclusion: This pilot study suggests that CMR assessment of scar burden more accurately predicts recurrent MR following CABG and anuloplasty for ischemic MR than do wall motion abnormalities. Routine preoperative CMR-derived scar burden may identify patients for whom alternative modes of treatment of ischemic MR should be considered.
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