Increased Pulse Pressure Amplification in Treated Hypertensive Subjects With Metabolic Syndrome

Abstract

Brachial pulse pressure (PP) is physiologically higher than central PP. This PP amplification, which protects the heart from increased afterload, is related to the progressive increase of arterial stiffness along the vascular tree and subsequent changes in pressure wave reflections. The PP amplification increases with high heart rate (HR), which is observed in subjects with metabolic syndrome (MS). The objective of this study was to investigate whether PP amplification is affected by MS and is related to cardiovascular (CV) risk. In 613 subjects treated for hypertension (41% with MS) pulse wave analysis was used to investigate carotid blood pressure (BP), pressure wave reflections from carotid augmentation index (AI), and arterial stiffness from aortic pulse wave velocity (PWV). The CV risk was estimated from standard Framingham equations. Pulse pressure amplification, HR, and PWV, but not AI, were increased in subjects with MS compared to control subjects without MS with the same age, gender, and mean arterial pressure. The difference in PP amplification between the two groups disappeared after adjustment for both HR and PWV. The AI was the main predictor of PP amplification, representing 28% and 19% of its total variance in subjects without and with MS, respectively. The CV risk for coronary, but not for cerebral, mortality was related to PP amplification. Although PWV is increased in treated hypertensive subjects with MS, compared to control, PP amplification is increased due to the effect of increased HR and attenuated pressure wave reflections. The observed relation of increased PP amplification with organ-specific CV risk needs further investigation.