Association Between Extracellular Matrix Expansion Quantified by Cardiovascular Magnetic Resonance and Short Term Mortality
Background—Extracellular matrix (ECM) expansion may be a fundamental feature of adverse myocardial remodeling, appears to be treatable, and its measurement may improve risk stratification. Yet, the relationship between mortality and ECM is not clear due to difficulties with its measurement. To assess its relationship with outcomes, we used novel, validated cardiovascular magnetic resonance (CMR) techniques to quantify the full spectrum of ECM expansion not readily detectable by conventional CMR.
Methods and Results—We recruited 793 consecutive patients at the time of CMR without amyloidosis or hypertrophic cardiomyopathy as well as 9 healthy volunteers (ages 20-50). We measured the extracellular volume fraction (ECV) to quantify the extracellular matrix expansion in myocardium without myocardial infarction (MI). ECV employs gadolinium contrast (Gd) as an extracellular space marker based on T1 measures of blood and myocardium pre-/post-Gd and hematocrit measurement. In volunteers, ECV ranged from 21.7-26.2%, but in patients, it ranged from 21.0-45.8%, indicating considerable burden. There were 39 deaths over a median follow-up of 0.8 years (IQR 0.5-1.2 years), and 43 individuals who experienced the composite endpoint of death/cardiac transplant/left ventricular assist device (LVAD) implantation. In Cox regression models, ECV related to all-cause mortality and the composite endpoint (HR 1.55; 95% CI 1.27-1.88 and HR 1.48; 95% CI 1.23-1.78, respectively, for every 3% increase in ECV), adjusting for age, left ventricular ejection fraction, and MI size.
Conclusions—ECV measures of extracellular matrix expansion may predict mortality as well as other composite endpoints (death/cardiac transplant/LVAD).
- Received December 22, 2011.
- Accepted June 22, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited