Severe regional myocardial dysfunction by stress echocardiography does not predict the presence of transmural scarring in chronic coronary artery disease.

Abstract

Detection and correct localization of transmural lesions can be important for optimal treatment of patients with chronic coronary artery disease (CAD). The aim of the study was to investigate the ability of peak longitudinal ejection strain (PLS) to detect the presence and extent of scar-tissue in CAD patients with normal or near normal ejection fraction, in comparison to cardiac magnetic resonance (CMR). Before coronary artery bypass grafting, 57 patients underwent late gadolinium enhancement (LGE) CMR and echocardiography at rest and dobutamine stress (DS). According to the degree of LGE, segments were allocated to groups of none, subendocardial (1-50%), subtotal (51-75%), and total transmural scars (>75%). Dysfunctional segments were identified by PLS or wall motion scores (WMS). The finding of normal/near normal resting WMS and PLS, excellently identified segments without transmural LGE (AUC 94.0 CI 90.6-97.3 and AUC 85.7 CI 79.0-92.3, respectively). However, the finding of akinesia did not necessarily indicate transmural scarring. The negative predictive value was high (99%, CI 98-100%) while the positive predictive value was low. Detection-rates for subendocardial LGE were low. Normo- and slightly hypokinetic myocardium by resting WMS or strain detects the absence of transmural scars. However, the finding of severe hypo- and akinesia does not reliably predict transmural scarring, with no improvement by the addition of DS. Detection of predominant akinesia with less than two normo- or hypokinetic segments in the territory of a high-grade coronary stenosis or occlusion, warrants further examination by LGE-CMR.