Incidence, predictors, and prognostic value of intramyocardial hemorrhage lesions in ST elevation myocardial infarction.

Background: Intra myocardial hemorrhage lesions (IMH) are underdiagnosed complication of ST elevation myocardial infarction (STEMI). We sought to determine the incidence, predictors and the prognostic value of IMH in STEMI using cardiac MR imaging (CMR) techniques.

Methods: We screened for inclusion consecutive patients with STEMI treated by percutaneous coronary intervention (PCI) within the first 12 hr of evolution. IMH lesions were identified on T2-weighted sequences on CMR between days 4 and 8 after PCI. Adverse cardiac events were defined as a composite of death + severe ventricular arrhythmias + acute coronary syndrome + acute heart failure.

Results: N = 114 patients were included and n = 11 patients (10%) presented IMH lesions. Patients with IMH lesions had a larger myocardial infarction extent (25.6 ± 1.8 vs. 13.5 ± 1.0 % LV mass, P < 0.01), microvascular obstructive lesions extent (4.6 ± 1.0 vs. 1.3 ± 0.3% LV mass, P < 0.01) and lower LV ejection fraction (40.7 ± 2.3% vs. 50.7 ± 1.3%, P < 0.01). The value of glycemia at admission was an independent predictor of IMH development (Odd ratio 1.8 [1.1-2.8] per mmol l(-1), P = 0.01). The incidence of adverse cardiac events was higher in the IMH group than in the non-IMH group during the first year following STEMI (P = 0.01, log-rank analysis). Cox regression analysis identified the presence of IMH lesions as an independent predictor of adverse clinical outcome (Hazard Ratio = 2.8 [1.2-6.8], P = 0.02).

Conclusion: Our study indicates that IMH is a rare but severe finding in STEMI, associated with a larger myocardial infarction and a worse clinical outcome. Per-PCI glycemia might influence IMH development.