ABSTRACT
BACKGROUND: Wall shear stress (WSS) has been shown to be a critical determinant of vessel diameter implicated in vascular remodeling and atherogenesis. Carotid intima-media thickness (IMT), resistive index (RI), and pulsatility index (PI) have been used as relevant indictors for carotid atherosclerosis. The study aimed to investigate the relationship between hemodynamic parameters in the common carotid artery (CCA) and the severity of carotid atherosclerosis in untreated hypertensive patients. METHODS: Duplex ultrasound was performed in 64 untreated hypertensive patients and 16 age-matched normotensive control subjects. Morphologic and hemodynamic parameters of CCA, including peak and mean WSS, RI, PI, and IMT were calculated after measuring internal diameter (ID) and flow velocity of CCA. RESULTS: Subjects with hypertension had lower peak and mean WSS than did normotensive control subjects (P < 0.05). Both carotid RI and PI were found to correlate inversely with mean WSS in hypertensive subjects. There was no correlation between carotid IMT and WSS. Stepwise multiple regression analysis for carotid RI and PI after adjustment for age, carotid IMT, and high sensitivity C-reactive protein (hsCRP) showed that mean WSS was an independent determinant of RI and PI. CONCLUSIONS: High carotid atherosclerotic indexes as expressed by both RI and PI are associated with low WSS in CCA. These findings indicate that local shear stress is associated with altered vascular pulsatility and resistance. Consequent alteration in local vascular dynamics could be an underlying mechanism for the progression of atherosclerosis.
Subject(s)
Carotid Artery Diseases/physiopathology , Carotid Artery, Common/physiopathology , Hypertension/physiopathology , Aged , Brachial Artery/physiopathology , Carotid Artery Diseases/etiology , Female , Hemodynamics , Humans , Hypertension/complications , Male , Middle Aged , Pulsatile Flow , Regression Analysis , Stress, MechanicalABSTRACT
The aim of this study was to identify which phase of wall shear stress (SS) augmentation during reactive hyperemia (RH) is the crucial determinant of endothelial reactivity. Fifty-three patients with untreated essential hypertension were enrolled. A 7.5-MHz linear array transducer was used to record the 2D images and Doppler flow signals of brachial artery at baseline and during RH. Wall SS and flow-mediated vasodilation were calculated sequentially. The result of this study demonstrated that augmentation of wall SS at end-diastolic phase during peak RH is the main rheologic determinant of endothelial function in patients with untreated essential hypertension.
Subject(s)
Brachial Artery/physiopathology , Endothelium, Vascular/physiopathology , Hyperemia/physiopathology , Hypertension/physiopathology , Shear Strength , Vasodilation/physiology , Adult , Blood Flow Velocity/physiology , Female , Humans , Male , Middle AgedABSTRACT
BACKGROUND: Pulse wave velocity (PWV), a relevant indicator of arterial stiffness, can be measured noninvasively with a variety of automatic devices, but most are complexly equipped. We developed a novel index for estimating arterial stiffness as "QPV interval," which was determined by means of surface electrocardiogram and Doppler ultrasound of the brachial artery simultaneously. HYPOTHESIS: This study aimed to validate the QPV interval as an exact and convenient index for estimation of arterial stiffness. METHODS: Forty-seven patients with untreated essential hypertension and 19 normotensive subjects were enrolled. Brachial-ankle PWV (baPWV) was measured using an automatic volume-plethysmographic apparatus, and Doppler ultrasound was implemented sequentially to measure the QPV interval in each subject. Clinical biochemistry and echocardiography were performed on the same day. RESULTS: Mean baPWV was significantly higher in hypertensive patients than in normotensive subjects (p = 0.002), whereas mean QPV interval was significantly shorter in hypertensive patients than in the normotensive group (p = 0.019). A simple regression analysis demonstrated an inverse correlation between the QPV interval and baPWV (r = -0.671, p < 0.001) in all enrolled subjects. In a stepwise regression model that adjusted for age, systolic blood pressure, and other determinants of baPWV, the negative association remained between the QPV interval and baPWV (p < 0.001). CONCLUSION: The QPV interval correlates inversely with baPWV, independent of age and other determinants of baPWV; hence, the QPV interval can serve as a simple and convenient index for assessing arterial stiffness in clinical practice.
Subject(s)
Blood Flow Velocity/physiology , Brachial Artery/diagnostic imaging , Hypertension/diagnostic imaging , Ultrasonography, Doppler , Adult , Aged , Brachial Artery/physiopathology , Cross-Sectional Studies , Echocardiography, Doppler , Electrocardiography , Female , Humans , Hypertension/physiopathology , Male , Middle Aged , Pulsatile Flow/physiology , Regression AnalysisABSTRACT
Relapsing polychondritis is a systemic autoimmune disease that may be associated with inflammatory arthritis, vasculitis, aortitis, and inflammation of the aortic valve and ring. Information describing the cardiac manifestations of relapsing polychondritis is limited. The authors encountered a patient with relapsing polychondritis who had pericardial effusion and aortic valve regurgitation. The patient's history is reported and relevant literatures are reviewed.
