Negative remodeling and calcified plaque in octogenarians with acute myocardial infarction: an intravascular ultrasound analysis.

Abstract

The goal of this study was to use intravascular ultrasound (IVUS) to compare octogenarians versus patients <65 years of age with regard to culprit lesion morphology in acute myocardial infarction (MI). Although octogenarians represent the fastest-growing segment of our population and have a higher risk profile, they are underrepresented in therapeutic trials. Between 2002 and 2005, 42 octogenarians and 52 patients <65 years of age underwent pre-intervention IVUS within 2 days from onset of an MI. Qualitative and quantitative measurements were performed at the lesion site and at the proximal and distal references. Positive remodeling was defined as a remodeling index (lesion/mean reference arterial area) > or =1. Elderly patients mostly (71%) presented with non-ST-segment elevation myocardial infarction (NSTEMI), whereas patients <65 years of age presented almost equally with ST-segment elevation myocardial infarction (STEMI) and NSTEMI (56% vs. 44%). The frequency of rupture/dissection was greater in the <65-year-old group (32% vs. 9%, p = 0.009), and culprit lesions contained more thrombus in this group (14% vs. 2%, p = 0.04). Conversely, in octogenarians, lesions were predominantly calcified (57% vs. 10%, p < 0.001) and longer (20.9 +/- 7.8 mm vs. 16.6 +/- 6.1 mm, p = 0.004) with less positive remodeling (19% vs. 56%, p < 0.001). On multivariant logistic regression analysis, age was the only independent predictor of calcified plaque (p = 0.02) and remodeling (p = 0.005). Negative remodeling and calcified plaque with rare plaque ruptured were common in elderly people with acute MI. These findings may contribute to the difference in clinical presentation and may suggest a different pathophysiologic mechanism of MI in octogenarians.