Abstract 5214: Microvascular Obstruction as Prognostic Marker for Long-Term Outcome After ST-Elevation Myocardial Infarction Compared to Traditional Prognostic Markers
Background Microvascular obstruction (MO) assessed by magnetic resonance imaging (MRI) has been shown to be a prognostic marker for combined clinical endpoints (including unstable angina and repeat target vessel revascularization) after ST-elevation myocardial infarction (STEMI) in a very limited number of patients. If MO gives also prognostic information for “hard” endpoints and whether MO adds information independent of traditional prognostic markers and scores has not been investigated, yet.
Methods and Results STEMI patients reperfused by primary PCI (n=408) underwent contrast-enhanced-MRI 4±7 days after the index event. Clinical follow-up was conducted after a mean of 18±11 months. The primary endpoint was defined as composite of death, non-fatal myocardial reinfarction and congestive heart failure. Secondary outcomes included the individual components of the composite endpoint. In 71% (n=286) MO was present. The composite clinical endpoint occured more frequently in patients with MO compared to patients without MO (19.6 vs. 6.7%, p=0.001). MO presence showed a trend towards higher occurrence of death (7.0 vs. 2.5%, p=0.09), reinfarction (5.6 vs. 1.7%, p=0.09) and congestive heart failure (7.0 vs. 2.5%, p=0.09). In a multivariate cox regression analysis including all parameters significant in univariate analysis (TIMI risk-score, Killip-class, ST-resolution, post-PCI TIMI-flow, infarct size, left-ventricular ejection fraction, endsystolic volume, age and diabetes mellitus), MO remained significantly associated with the occurrence of the composite endpoint (p=0.04). Apart from MO only post-PCI TIMI-flow (p=0.03), diabetes (p=0.03) and age (p=0.05) remained significant predictors for the combined clinical endpoint. The strongest predictor for the occurrence of the combined clinical endpoint was MO (OR 2.5; 95%CI 1.1–5.9), followed by post-PCI TIMI-flow (OR 2.3 95%CI 1.1– 4.9), diabetes (OR 1.8 95%CI 1.1–3.1) and age (OR 1.8 95%CI 1.0 –3.2).
Conclusion Compared to traditional prognostic markers and scores, MO is the strongest predictor for the occurrence of death, non-fatal myocardial reinfarction and congestive heart failure after STEMI. Thus, cardiac MRI adds important information regarding post-infarction prognosis.