Abstract 605: Diastolic Blood Pressure Predicts Coronary Plaque Volume in Patients With Coronary Artery Disease

Abstract

Introduction: Hypertension is a major risk factor for coronary artery disease (CAD) and is associated with increased morbidity and mortality. The effect of systolic vs. diastolic blood pressure (BP) on coronary plaque volume has not been reported. Coronary blood flow occurs during diastole; shear stress affects plaque formation. Hypothesis: Diastolic BP may be a better predictor of plaque volume than systolic BP. Methods: 285 subjects with stable CAD underwent coronary computed tomographic angiography to assess the indexed volume (plaque volume [mm3] divided by segment length [mm]) of fatty, fibrous, non-calcified, calcified and total coronary plaque. Segments with significant calcium-blooming artifact were excluded. A backward linear regression model adjusted for age, gender, BMI, estimated glomerular filtration rate, total cholesterol, LDL-C, HDL-C and triglycerides. Results: Mean (SD) age was 63.1 ± 7.7 years (18% female). A significant increase was observed in volume of all plaque components across diastolic BP tertiles except for calcified which was borderline (p= 0.069) (Table). In contrast, there was no difference in systolic tertiles. In multivariate regression, diastolic BP tertile was a significant independent predictor of volume of all plaque components - fatty (β= 0.075; p=0.038), fibrous (β= 0.178; p= 0.004), non-calcified (β= 0.256; p= 0.008), calcified (β= 0.081; p= 0.007) and total (β= 0.353; p= 0.002) whereas no association was observed between systolic BP tertile and volume of any plaque component (Table). Conclusion: In patients with CAD, diastolic BP tertile independently predicts coronary plaque volume whereas systolic BP tertile does not. Since coronary blood flow occurs during diastole, a possible mechanism for the difference between systolic and diastolic BP is increased shear stress during diastolic blood flow. Therefore, control of diastolic BP may be an important factor in determining plaque volume.