Abstract 15506: Ischemic Time: a Better Predictor Than Door-to-Balloon Time for Infarct Size in STEMI by Cardiac Magnetic Resonance Imaging
Background: Current STEMI treatment guidelines strongly recommend early revascularization with optimal ischemic time (IT) <120 min and door-to-balloon (D2B) time <90 min. Revascularization delays lead to larger infarct size with associated increased cardiac morbidity and mortality. However, total IT is not tracked in most current registries. We tested the hypothesis that IT is a better predictor than D2B time for infarct sizes.
Methods: Between 8/2005 and 7/2010, 262 STEMI patients underwent delayed enhancement cardiac MRI (DEcMRI) on day 3-5 to measure scar and microvascular obstruction (MVO) volumes, as well as transmural extent. Total IT and D2B times were recorded and correlated with infarct size measurements. Patients were divided into groups according to IT (<120, 120-239, ≥240 min) and D2B time (<30, 30-59, 60-89, and ≥90 min).
Results: Baseline demographics were similar between groups. Infarct size nearly doubled (11.2 cc to 21.4 cc, p=0.02) and MVO quadrupled (0.8 cc to 3.3 cc, p<0.01) when IT increased from <120 min to ≥240 min. In contrast, increases in D2B time did not correlate with either scar volume (D2B time <30 min = 14.5 cc, ≥90 min = 21.1 cc; p=NS) or MVO (D2B time <30 min = 1.8 cc, ≥90 min = 3.0 cc; p=NS).
Conclusion: In STEMI patients, total IT is a better predictor than D2B times for infarct size and MVO as measured by DEcMRI. Our findings suggest the focus of STEMI care should be directed at early therapy initiation with minimizing of IT rather than D2B time alone. The potential impact of IT tracking in current STEMI registries warrants further investigation.
- © 2011 by American Heart Association, Inc.