Abstract-Hyperhomocysteinemia has been associated with both vascular structure alterations and vascular clinical end points. To assess the relation between plasma homocysteine, structure and function of large arteries, and the presence of clinical vascular disease, we investigated a population of 236 hypertensive patients. We estimated arterial stiffness by measuring the carotid-femoral pulse wave velocity. Total plasma homocysteine was determined by fluorometric high-performance liquid chromatography. The presence of cardiovascular disease was defined on the basis of clinical events, including coronary heart disease, cerebrovascular disease, and peripheral vascular disease. In this population, pulse wave velocity was positively correlated with homocysteine, even after adjustments for age, mean blood pressure, extent of atherosclerosis, and creatinine clearance (Pϭ0.016). Analysis of variance showed statistically significant differences between the mean values of homocysteine, creatinine clearance, and pulse wave velocity according to the extent of atherosclerosis, with an increase in these 3 parameters concomitant with an increase in the number of vascular sites involved with atherosclerosis. In conclusion, in hypertensive patients the levels of homocysteine are strongly and independently correlated to arterial stiffness measured by aortic pulse wave velocity. Plasma homocysteine, creatinine clearance, and aortic pulse wave velocity are higher in patients presenting with clinical vascular disease. These results suggest that the evaluation of aortic distensibility and homocysteine levels can help in cardiovascular risk assessment in hypertensive populations. Key Words: homocysteine Ⅲ arteries Ⅲ blood flow velocity Ⅲ vascular diseases Ⅲ hypertension, renovascular C ardiovascular (CV) disease (CVD) is a major cause of morbidity, dependence, and mortality worldwide. Besides the well-accepted CV risk factors such as smoking, diabetes mellitus, dyslipidemia, and hypertension, hyperhomocysteinemia is emerging as an independent and graded risk factor for stroke, myocardial infarction, and CV death. [1][2][3] Although there is considerable epidemiological evidence for a relationship between plasma homocysteine and CVD, not all prospective studies have supported such a relationship. 4 -8 Moreover, it is not known whether a reduction in plasma homocysteine will reduce CVD risk. 9,10 Experimental studies have demonstrated that hyperhomocysteinemia can induce smooth muscle cell proliferation, 11 endothelial dysfunction, 12 collagen synthesis, and deterioration of elastic material of the arterial wall. 13 In humans, plasma homocysteine levels were found to be positively correlated with carotid artery intimalmedial wall thickness 14 and with extracranial carotid artery stenosis. 15 Regarding the relationships between homocysteine and hypertension, 2 studies noted a synergistic effect of these parameters on CV risk, 16,17 and Sutton-Tyrrell et al 18 reported an independent relationship between high homocysteine levels and is...

The results of the study suggest that chronic exposure to high levels of plasma ACE could be involved in structural changes of the arterial wall.

Recent research in ultrasound technology has led to the development of a high-resolution echo-tracking device. The present study was performed to evaluate the accuracy in the measurement of human radial artery intima-media thickness with this new device. We determined the correlation between histological and ultrasonic measurements of intima-media thickness in 15 radial artery segments obtained from the distal end of the wrist-elbow harvest for coronary bypass grafting in patients with coronary heart disease. For arterial intima-media thickness, a positive correlation was observed between ultrasonic and histological measurements (r = 0.618; p& < 0.014), and the difference between ultrasound and histology measurements was 41 ± 66 µm, with the higher measurements found by the ultrasonic device. In a subgroup of 11 patients, we determined the correlation between in vivo ultrasonic measurements of radial artery intima-media thickness at the preoperative stage and in vitro ultrasonic measurements of intima-media thickness obtained postoperatively in the same arterial segments. Internal diameter was larger in vivo than in vitro, and intima-media thickness was smaller in vivo than in vitro. The cross-sectional area of the arterial wall was calculated from internal diameter and intima-media thickness. In vitro wall cross-sectional area was correlated with in vivo wall cross-sectional area (r = 0.929; p& < 0.0001). Repeatability of in vivo intima-media thickness measurements was investigated in 10 subjects through the calculation of the repeatability coefficient as defined by the British Standards Institution. Intraobserver repeatability coefficient (comparison of two determinations, separated by a 10-min interval, obtained by the same observer) was 48.7 µm. These results indicate that the radial artery intima-media thickness can be accurately measured in humans.