Quantitation of the thickness of the non-enhanced myocardial rim predicts recovery of territorial myocardial function in chronic ischemic heart disease: a cardiac magnetic resonance imaging study.

OBJECTIVES

We sought to determine whether the thickness of the non-contrast-enhanced myocardial rim (RIM) predicts recovery of territorial myocardial function after revascularization in chronic ischemic cardiomyopathy (ICM).

BACKGROUND

Non-contrast-enhanced dysfunctional myocardium at late gadolinium-enhanced CMR depicts the presence of viable myocardium.

METHODS

In 29 patients (65 +/- 8 years) with ICM (EF 33 +/- 10), ceCMR and cine images were acquired 5 +/- 10 days before revascularization. Cine images were repeated after 6 months. Regional wall thickness, wall thickening and RIM were determined in each of 12 segments per short-axis slice (4-8/patient), which were assigned to the respective supplying coronary artery (LAD, LCX and RCA). A threshold for normal wall-thickening was derived from a control group (n = 14; 52 +/- 17 years). Functional improvement at follow-up was defined as wall thickening >2 mm.

RESULTS

Of the 1,896 analyzed segments, 655 segments showed severe dysfunction. At follow-up, 307 segments demonstrated functional improvement. The RIM differed between segments with and without improvement (6.6 +/- 2.4 mm vs. 2.8 +/- 2.0 mm; p < 0.0001). The area under the receiver operator characteristic (ROC) for predicting overall functional recovery was 0.91 (95%, CI 0.88-0.93, p < 0.001). A RIM of 4.0 mm predicted functional recovery after revascularization of the supplying coronary artery with a sensitivity and a specificity of 88 and 82% for the LAD, 96 and 86% for the RCA and 88 and 83% for the LCX, respectively.

CONCLUSION

RIM may be a useful marker for predicting territorial functional recovery after revascularization in patients with chronic ICM.