Myocardial Thinning in Patients With Coronary Artery Disease

Abstract

To the Editor The study by Dr Shah and colleagues 1 reported that among patients with coronary artery disease (CAD), limited scar burden was present in 18% of the patients with regional wall thinning detected by cardiovascular magnetic resonance (CMR) imaging, which challenges common assumptions. We believe some other considerations should be taken into account. First, a prior study 2 revealed that most infarct healing (in terms of reduction in infarct size and wall thinning) was completed by 5 months after a myocardial infarction (MI); however, another study 3 indicated that 4 months is most likely too early to detect the full extent of regional and global left ventricular remodeling. Therefore, controversy exists regarding the time course of myocardial thinning after an ischemic event. In the study by Shah et al, 1 the time span between diagnosis of CAD and assessment by delayed-enhancement CMR imaging was not mentioned. Second, although infarct scar tissue has been considered inert, it is now recognized to be living tissue, with vascular growth 4 and connective tissue accumulation at the infarct site for years after an MI has occurred. In the study by Shah et al, 1 71% of the patients with myocardial thinning had a history of MI, and there were significantly more collateral vessels in the limited scar burden group than in the extensive scar burden group, which could lead to differences in contrast accumulation in the thinning region and cause bias in the assessment of scar burden. Third, the use of anticoagulants could influence the development of myocardial scar burden. Although there was no significant difference in aspirin use between the limited scar burden and the extensive scar burden groups, the authors should present more information about other anticoagulants (ie, clopidogrel, heparin, and glycoprotein IIb/IIIa receptor antagonists) in their study.