116: Quantitative analysis of microvascular obstruction is bestly related to clinical prognosis than clinical markers at a 1 year follow-up: a contrast-enhanced MRI study

Abstract

To evaluate the clinical prognostic value of a cardiac magnetic resonance (CMR) assessment soon after a first ST-segment elevation myocardial infarction (STEMI). Clinical factors such as gender, age, blood pressure, heart beat, heart and renal failure have already been described as related to poor clinical prognosis at follow-up. For now, the prognostic value and weight of CMR parametersis not well-defined. We followed for 1 year up to 168 consecutive patients with a firstSTEMI treated with primary angioplasty. We performed CMR at day 5±2 and 3months to assess LV volumes. We used delayed enhancement imaging to assess the infarct size and the presence of MVO. We defined severe MVO as MVO extent being superior to its median value (2,82 gr). 13 major adverse cardiac events (MACE) including 2 cardiac deaths, 1 nonfatal myocardial infarctions, 8 readmissions for heart failure and 2 stroke were documented. In univariate analysis, the MACE was related to age, creatin kinase peak, heart failure, MVO and LV volumes. In a complete multivariate analysis, age (hazard ratio 1.075, p=0.003), end-diastolic LV volume (HR 0.74, p=0.017), end-systolic LV volume (HR 1.046, p=0.039), MVO presence (HR 8.867, p=0.041; Log rank=9.195, p=0.002) and severe MVO (HR 9.906, p=0.002; Log rank=18.090, p<0.001) were the only independent prognostic variables. Of note, clinical marker such as heart failure was strongly related to age and found as non significant in multivariate analysis. A comprehensive CMR assessment is useful for stratifying risk soon after STEMI; baseline LV volumes and severe MVO are the stronger independent prognosis factor. This result supports the clinical interest of a quantitative assessment of MVO.