Abstract 13593: Infarct Tissue Heterogeneity by Contrast-Enhanced MRI is a Novel Predictor of Mortality in Patients with Coronary Artery Disease with Reduced Left Ventricular Systolic Function
Background: While LVEF is the robust marker of mortality in patients (pts) with chronic CAD, majority of sudden cardiac death (SCD) occurs in pts with preserved LVEF and current strategies to identify such pts at risk are deficient. Peri-infarct zone (PIZ) assessed by cardiac MRI (CMR), as a marker of infarct tissue heterogeneity, has been linked to arrythmogenic substrates and reduced post-MI survival. However, the prognostic implication of PIZ has not been studied in a large consecutive group of pts with chronic CAD and reduced LVEF. We hypothesized that PIZ provides strong association with mortality in pts with chronic CAD and this association is especially prominent in pts with only mild to moderate reduction of LVEF (>35%).
Methods: We studied 305 pts with CAD and a LVEF <60% referred for CMR (mean age 62±11 years, mean LVEF 41±14%). Late gadolinium enhancement was performed 10-15 minutes after a cumulative dose of 0.15-0.2 mmol/kg of Gd-DTPA. A semi-automatic algorithm quantified the infarct core and PIZ using SI criteria of >3SDs and 2 to 3SDs above the remote myocardium, respectively. The PIZ was expressed as a percentage of the total infarct mass (%PIZ).
Results: Late gadolinium enhancement was present in 231 pts (76%). Mean total infarct mass and %PIZ were 15±21g and 20±18%, respectively. After a median follow-up of 3.9 years, 66 (22%) pts died; with 34 deaths occurred among 198 (65%) pts with LVEF>35%. %PIZ was the strongest univariable predictor of all-cause mortality (HR=1.27, LRχ2=15.03, p=0.0001). Adjusted for pt age, LVEF, RVEF, and infarct size, %PIZ maintains a strong association with mortality (HR=1.21, LRχ2=8.42, p=0.004). Multivariable regression identified a presence of long QTc and %PIZ as the strongest predictors that form the best overall model for mortality in the entire cohort. In pts with LVEF>35%, %PIZ was the strongest multivariable predictor of mortality (HR=1.34, LRχ2=11.53, p=0.0007).
Conclusion: Infarct heterogeneity characterized by %PIZ demonstrated a strong association with patient mortality independent of pt age, LVEF, RVEF, and infarct size. CMR infarct heterogeneity may provide unique information regarding risk to SCD in CAD pts with LVEF>35% where the role of ICD therapy is currently unclear.
- © 2011 by American Heart Association, Inc.