Cardiac magnetic resonance imaging: infarct size is an independent predictor of mortality in patients with coronary artery disease

Background

Cardiac magnetic resonance imaging (CMR) can accurately determine infarct size. Prior studies using indirect methods to assess infarct size have shown that patients with larger myocardial infarctions have a worse prognosis than those with smaller myocardial infarctions.

Objectives

This study assessed the prognostic significance of infarct size determined by CMR.

Methods

Cine and contrast CMR were performed in 100 patients with coronary artery disease (CAD) undergoing routine cardiac evaluation. Infarct size was determined by planimetry. We used Cox proportional hazards regression analyses (stepwise forward selection approach) to evaluate the risk of all-cause death associated with traditional cardiovascular risk factors, symptoms of heart failure, medication use, left ventricular ejection fraction, left ventricular mass, angiographic severity of CAD and extent of infarct size determined by CMR.

Results

Ninety-one patients had evidence of myocardial infarction by CMR. Mean follow-up was 4.8±1.6 years after CMR, during which time 30 patients died. The significant multivariable predictors of all-cause mortality were extent of myocardial infarction by CMR, extent of left ventricular systolic dysfunction, symptoms of heart failure, and diabetes mellitus (P<.05). The presence of infarct greater than or equal to 24% of left ventricular mass and left ventricular ejection fraction less than or equal to 30% were the most optimal cut-off points for the prediction of death with bivariate adjusted hazard ratios of 2.11 (95% confidence interval 1.02-4.38) and 4.06 (95% confidence interval 1.73-9.54), respectively.

Conclusions

The extent of myocardial infarction determined by CMR is an independent predictor of death in patients with CAD.