Utility of cardiovascular magnetic resonance to predict left ventricular recovery after primary percutaneous coronary intervention for patients presenting with acute ST-segment elevation myocardial infarction.

Cardiac magnetic resonance (CMR) has been shown to predict left ventricular (LV) recovery in patients after acute ST-segment elevation myocardial infarction. The purpose of this investigation was to determine the relative values of infarct transmurality and microvascular obstruction (MVO) using delayed enhancement CMR to predict LV recovery. We studied 17 patients (mean age 60 +/- 10 years, 14 men) presenting with first acute ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention who underwent CMR within 6 days after presentation and again at 6 months. In total 680 myocardial segments were evaluated, of which 267 (39%) demonstrated delayed hyperenhancement (DHE) and 116 (18%) demonstrated MVO. Unadjusted odds ratio (OR) for any improvement in regional LV function with increasing DHE category (<50%, 51% to 75%, >75% transmurality) was 0.20 (95% confidence interval [CI] 0.13 to 0.30, p <0.0001), whereas it was 0.40 (95% CO 0.28 to 0.55, p <0.0001) with increasing MVO category (0, <50th, >50th percentile). However, when coadjusted together, the relation remained robust with regard to degree of transmurality of DHE (OR 0.21, 95% CI 0.13 to 0.36, p <0.0001), but the relation was lost for MVO (OR 0.90, 95% CI 0.58 to 1.40, p = 0.64). In conclusion, when using the delayed enhancement technique for assessment of DHE and MVO, degree of infarct transmurality appears to be a more powerful predictor of LV recovery by CMR.