Negative remodeling and calcified plaque in octogenarians with acute myocardial infarction - An intravascular ultrasound analysis

OBJECTIVES 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). BACKGROUND Although octogenarians represent the fastest-growing segment of our population and have a higher risk profile, they are underrepresented in therapeutic trials. METHODS 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) >= 1. RESULTS 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 min 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). CONCLUSIONS 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.