Regional Left Ventricular Myocardial Dysfunction as a Predictor of Incident Cardiovascular Events: MESA (Multi-Ethnic Study of Atherosclerosis)
What is the diagnostic value of subclinical left ventricular (LV) regional myocardial dysfunction (RMD) in a large multi-ethnic asymptomatic population using cardiac magnetic resonance imaging (CMR)?
This a substudy the Multi-Ethnic Study of Atherosclerosis (MESA), which was a multicenter prospective study of 6,814 asymptomatic and clinically disease-free individuals, 4,510 of whom had CMR and were followed for outcomes for 4-6 years. The primary endpoint was incident congestive heart failure (CHF), and secondary endpoints included hard coronary events of myocardial infarction or coronary-related death, stroke, and composites of all atherosclerotic events. CMR was analyzed on a 16-segment model as systolic wall thickening.
RMD was noted in 1,154 subjects (25.6%) and involved one, two, and all three coronary territories in 815 (18.1%), 263 (5.8%), and 76 (1.7%) subjects, respectively. CHF developed in 64 subjects (1.4%), 16 of whom had interim myocardial infarction. CHF was classified as systolic in 35 (54.7%) and diastolic in 21 (32.8%), and unclassifiable in the remainder of the subjects. Any coronary event or cardiovascular event was noted in 134 (4.0%) of those without RMD and in 66 (5.7%) subjects with RMD (p = 0.012). Subjects without and with RMD were similar with respect to age, ethnicity, history of hypertension, body mass index, smoking status and diabetes. CHF developed in 1% of those without RMD and 2.6% with RMD (hazard ratio [HR], 2.62; p < 0.01). Hard coronary events occurred in 1.5% without RMD and 2.5% with RMD (HR, 1.72; p = 0.02) and any coronary event in 2.9% and 4.3% (HR, 1.51; p = 0.017). RMD remained an independent predictor of CHF after adjusting for multiple clinical variables, biomarkers, and global LV systolic function.
The authors concluded that regional wall motion abnormalities (RWMAs) noted on CMR in asymptomatic patients are independent predictors of subsequent CHF and other atherosclerotic cardiovascular events.
MESA is a large-scale multicenter evaluation of the relationship between a wide range of cardiovascular risk factors and demographics to subsequent development of CHF and other cardiovascular events. Multiple details of this study have been previously published. This study is unique for the substantial number of the subjects evaluated, over 5,000 of whom underwent CMR for evaluation of structure and function. This study reports on over 4,500 of them who had an analyzable CMR and follow-up, and nicely demonstrates a substantial (25%) prevalence of asymptomatic and clinically unrecognized RWMAs. RWMAs in asymptomatic individuals have been noted previously using echocardiography. While the precise underlying mechanism of the RMD is not known, a link to presumed coronary artery disease is plausible. The link between RWMAs and subsequent events was additive to multiple clinical and demographic features, and is also independent of global left ventricular systolic function. The limited RWM in patients with preserved systolic function at baseline who sustained subsequent events suggests that an RWD was a marker for a more diffuse underlying process.
Keywords: Coronary Artery Disease, Myocardial Infarction, Follow-Up Studies, Atherosclerosis, Biological Markers, Ventricular Function, Left, Heart Failure, Magnetic Resonance Imaging, Echocardiography
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