Prognostic relevance of peri-infarct zone measured by cardiovascular magnetic resonance in patients with ST-segment elevation myocardial infarction

Abstract

Background: Cardiac magnetic resonance (CMR) imaging provides valuable prognostic information in patients with ST-elevation myocardial infarction (STEMI). The peri-infarct zone (PIZ) is a potential marker for post-infarction risk stratification. The aim of this study was to assess the prognostic impact of PIZ in a large multicenter STEMI-trial.

Methods: The study population consisted of 704 consecutive patients undergoing CMR within 10 days after STEMI to assess established parameters of myocardial injury and additionally the extent of PIZ. The primary clinical endpoint was major adverse cardiac events (MACE) consisting of death, re-infarction and new congestive heart failure within 1 year after infarction.

Results: The median heterogeneous PIZ-volume in the overall population was 14 ml (interquartile range [IQR] 7 to 24 ml). Male sex, infarct size, and left ventricular ejection fraction were identified as independent predictors of larger PIZ alterations. Patients with MACE had a significantly larger PIZ volume compared to patients without adverse events (21 ml [IQR 12 to 35 ml] versus 14 ml [IQR 7 to 23 ml]; p = 0.001). In stepwise multivariable Cox regression analysis, PIZ > median (>14 ml) emerged as an independent predictor of MACE (hazard ratio [HR] 2.84; 95% confidence interval [CI] 1.34 to 6.00; p = 0.006) in addition to the Thrombolysis In Myocardial Infarction (TIMI) risk score (HR 1.53; 95% CI 1.19 to 1.53; p < 0.001). Addition of PIZ to a CMR risk model comprising LVEF, infarct size and microvascular obstruction resulted in net reclassification improvement of 0.46 (0.19-0.73, p < 0.001).

Conclusion: In this currently largest prospective, multicenter CMR study assessing PIZ, the extent of PIZ emerged as an independent predictor of MACE and a potential novel marker for optimized risk stratification in STEMI patients. ClinicalTrials.gov: NCT00712101.

Keywords: CMR; Infarct heterogeneity; Myocardial infarction; Peri-infarct zone; Prognosis.