Abstract 13956: High Risk Patients with ST-segment Elevation Myocardial Infarction on The Global Registry of Acute Coronary Events (GRACE) Risk Score Have Higher Index of Microcirculatory Resistance Values
Background: Index of microcirculatory resistance (IMR) has been proposed as a novel predictor of microvascular dysfunction and recovery of left ventricular function after ST-segment elevation myocardial infarction (STEMI). However, the impact of IMR values on mortality risk in STEMI remains uncertain. One previous study showed high risk patients with acute coronary syndromes on the Global Registry of Acute Coronary Events (GRACE) risk score benefits more from early-intervention (coronary angiography≤24 hours) than low-to-intermediate risk.
Objective: We investigated whether high risk patients with ST-segment elevation myocardial infarction on the GRACE risk score have higher IMR values.
Methods and Results: We investigated the association between the GRACE risk score for predicting in-hospital mortality and IMR after primary percutaneous coronary intervention (PCI) in patients with STEMI. Seventy-one consecutive patients with STEMI (mean age: 65±11 years, male: 59, female: 12) were divided into two groups (low-to-intermediate risk: 49–154, and high risk: 155–319 on GRACE risk score). Following successful PCI, IMR was measured using a PressureWireTM Certus (St. Jude Medical, USA) at maximal hyperemia. In the high risk group (n=33), higher IMR values were observed as compared with the low-to-intermediate risk group (n=38) (39.3±26.8 U versus 28.2±25.2 U, P=0.024).
Conclusions: High risk patients with STEMI on the GRACE risk score had significantly higher IMR values than the low-to-intermediate risk patients. The result indicates that higher microvascular resistance levels after primary PCI are at least partly associated with mortality risk in patients with STEMI. Figure:The average index of microcirculatory resistance (IMR) values in patients with a risk score of more than 155 on the Global Registry of Acute Coronary Events (GRACE) risk score (high risk,n) were higher than patients with a risk score of 154 and less (low-to-intermediate risk).
- © 2010 by American Heart Association, Inc.