Background: The risk of plaque disruption and subsequent thrombosis in patients with unstable angina depends on the plaque type and size.
Design: Intravascular ultrasound (IVUS) was employed to illustrate the correlation between risk factors and plaque morphology in patients with unstable angina.
Methods: In a prospective study of 60 of 95 patients consecutively admitted with unstable angina [41 men, aged 61.2 +/- 8.1 years (mean +/- SD)], qualitative (soft and hard plaque, thrombus, calcification, eccentricity, adaptive and constrictive remodeling) and quantitative [lumen, external elastic membrane (EEM) and plaque cross-sectional area (CSA) and plaque burden] IVUS data relating to the target lesion, and proximal and distal reference segments were analyzed and correlated with risk factors. Univariate and multivariate nominal logistic regression analyses and analyses of variance were used to determine the independent predictors for IVUS morphology.
Results: For plaque composition univariate analysis showed a younger age (< 60 years) to be a predictor for adaptive remodeling (P = 0.019), and an older age to be a predictor for constrictive remodeling (P = 0.021). Hypercholesterolemia, smoking and sex were associated with a higher frequency of thrombus (P = 0.044, 0.038 and 0.043, respectively). Multivariate analyses revealed that only younger and older ages were independent predictors for adaptive and constrictive remodeling (P = 0.039 and P = 0.045). For plaque size, univariate and multivariate analyses demonstrated that diabetes mellitus and hypercholesterolemia were independent predictors for greater plaque (13.5 +/- 5.72 versus 10.17 +/- 4.6 mm2, P = 0.015, for diabetic versus non-diabetic patients; 12.0 +/- 5.35 versus 9.03 +/- 3.76 mm2, P = 0.010, for hypercholesterolemic versus normocholesterolemic patients) and EEM CSA (17.16 +/- 5.81 versus 14.3 +/- 5.1 mm2, P = 0.033, for diabetic versus non-diabetic patients; 16.57 +/- 5.49 versus 12.25 +/- 3.8 mm2, P = 0.001, for hypercholesterolemic versus normocholesterolemic patients) at the target lesion. Hypercholesterolemia was associated with significantly greater plaque and EEM CSA in both proximal and distal reference segments.
Conclusions: Multivariate analyses indicated that age, diabetes and hypercholesterolemia are independent predictors for plaque morphology in patients with unstable angina.