Noninvasive assessment of endothelial activity in patients with peripheral arterial disease and cardiovascular risk factors.

Microvascular endothelial activity (EA) after stimulation with iontophoretically administered acetylcholine was evaluated using laser Doppler fluxmetery (LDF) and calibrated photoplethysmography (c-PPG) in normal patients and patients with peripheral artery disease (PAD). The patients included 79 non-PAD subjects and 51 patients with PAD. Upper and lower extremity EA was examined using LDF and c-PPG after acetylcholine iontophoresis for 10 min. Sensitivity and specificity were assessed using integrated area under response curve. In non-PAD patients, the EA by LDF in the upper extremity was significantly lower in the older patients compared to the younger patients. Conversely, EA by LDF detected no significant difference between these groups in the lower extremity.With c-PPG, the EA was slightly reduced in the upper but not in the lower extremity in older patients. Comparing PAD patients to the older patients, there was a significantly lower EA response in the upper and lower extremities by LDF. Likewise, c-PPG detected a highly significantly reduced EA in the upper and lower extremities for PAD patients. These results indicated that using a noninvasive technique to determine EA, there were significant differences in the EA response to acetylcholine between those with PAD and normal patients over the age of 50. Importantly, the EA response was reduced in the upper and lower extremities, indicating systemic disease of the endothelium in PAD patients.

The associations between visceral fat and calcified atherosclerosis are stronger in women than men.

BACKGROUND: Previous studies have found a significant association between body mass index (BMI) and coronary artery calcium (CAC). Little is known about whether body fatness is linked with atherosclerotic calcium (AC) in the non-coronary vasculature. Accordingly, this study tested the hypothesis that there would be significant associations between CAC and AC in the non-coronary vasculature and BMI, visceral fat (VF), and percent body fat (BF%). METHODS: Subjects (n=1160; mean age 57 years; 55% men) underwent electron beam computed tomography (EBCT) screening for AC in the carotid, coronary, thoracic and abdominal aorta, and iliac arteries. Visceral fat and BF% were measured using EBCT and electrical bioimpedance analysis, respectively. RESULTS: In sex-stratified models adjusted for CVD risk factors, there were significant associations among both sexes between 1-SD increments of BMI, BF% and VF and the presence of CAC (p<0.01) as well as for quartiles of BMI and VF and prevalent CAC. Higher levels (tertiles) of BF% and VF were significantly associated with higher amounts of both abdominal aortic calcium (OR=1.90, 1.57 with p=0.02, 0.05 in females and males, respectively) and CAC. CONCLUSIONS: Measures of body morphology are significantly associated with AC in the coronary arteries and abdominal aorta. Of the measures studied, VF appears to be the most relevant by having the most consistent and stronger magnitudes of association, especially in women. These results suggest that VF may be more relevant in women than men with respect to the presence and extent of atherosclerosis in multiple vascular beds.

Preliminary report: hepatic fat and inflammation in type 2 diabetes mellitus.

Although the association between inflammation and hepatic fat is fairly established, it remains unclear whether this association is independent of general measures of obesity and standard cardiovascular risk factors. Therefore, the aim of this study was to investigate the contribution of hepatic steatosis as an independent predictor of chronic inflammation in 281 subjects with type 2 diabetes mellitus. Reduced hepatic steatosis significantly (P < .01) correlated with C-reactive protein (r = -0.16) and adiponectin (r = 0.23). The association of hepatic steatosis with both C-reactive protein and adiponectin remained significant after adjustment for age, ethnicity, body mass index (or waist circumference), triglycerides, high-density lipoprotein, and total cholesterol. These data support the concept that accumulation of hepatic fat is related to enhanced inflammation in type 2 diabetes mellitus independent of general measures of obesity and standard cardiovascular risk factors.

The epidemiology of abdominal aortic diameter.

BACKGROUND: The diameter of the abdominal aorta is central to the diagnosis of abdominal aortic aneurysm. This study aimed to determine the associations between the diameter of the abdominal aorta at three distinct locations and the traditional cardiovascular disease risk factors as well as calcified atherosclerosis. METHODS: A total of 504 patients (41% women) underwent whole body scanning by electron beam computed tomography (EBCT) and a standardized assessment for cardiovascular disease risk factors. The resulting EBCT images were retrospectively interrogated for the diameter of the abdominal aorta just inferior to the superior mesenteric artery (SMA), just superior to the aortic bifurcation, and at the midpoint between the SMA and bifurcation. RESULTS: Mean patient age was 57.8 years. The mean (SD) diameter was 21.3 (2.9) mm at the SMA, 19.3 (2.5) mm at the midpoint, and 18.6 (2.2) mm at the bifurcation. In a model containing the traditional cardiovascular disease risk factors, age (standardized beta = 0.96), male sex (beta = 3.06), and body mass index (standardized beta = 0.68) were significantly associated with increasing aortic diameter at the SMA (P < .01 for all). The significance of the associations for these variables was the same for aortic diameter at the midpoint and bifurcation. Furthermore, a 1-unit increment in the calcium score in the abdominal aorta and iliac arteries was associated with 0.13-mm (P < .01) and 0.09-mm (P = .02) increases, respectively, in aortic diameter at the SMA. The results were similar for the midpoint (beta = 0.19, P < .01; beta = 0.12, P = .01, respectively) and bifurcation (beta = 0.09, P < .04; beta = 0.09, P = .03, respectively). CONCLUSIONS: Age, sex, body mass index, and the presence and extent of calcified atherosclerosis in both the abdominal aorta and iliac arteries are significantly associated with increasing aortic diameter independent of the other cardiovascular disease risk factors.

Renal artery calcium is independently associated with hypertension.

OBJECTIVES: We tested the hypothesis that renal artery calcium (RAC), a marker of atherosclerotic plaque burden, is also significantly associated with higher blood pressure levels and a diagnosis of hypertension. BACKGROUND: In the nonrenal systemic vasculature, atherosclerotic plaque burden has been shown to be significantly associated with hypertension. METHODS: A total of 1,435 consecutive patients were evaluated at a university-affiliated disease prevention center for the extent of calcified atherosclerosis in the systemic vasculature. RESULTS: The overall prevalence of calcium in either renal artery was 17.1%, with men having a significantly higher prevalence (19.0%, 153 of 804) than women (14.7%, 93 of 631) (p = 0.03). After adjustment for age and gender, subjects with a RAC score >0 had a significantly higher prevalence of hypertension (41.2 vs. 29.5, p < 0.01). In a logistic model that adjusted for age, gender, body mass index, percent body fat, diabetes, smoking, dyslipidemia, and the extent of calcified atherosclerosis in the nonrenal vasculature, those with any RAC had a significantly higher odds ratio (1.61, p = 0.01) for hypertension than those with no RAC. CONCLUSIONS: The results of this study suggest that the presence of RAC is associated with higher odds for prevalent hypertension, independent of CVD risk factors and the extent of calcified atherosclerosis in the nonrenal vasculature.

Renal artery calcium: relationship to systemic calcified atherosclerosis.

In this study we tested the hypothesis that calcium due to atherosclerosis in the renal arteries would be significantly associated with calcium in multiple other vascular beds, independent of traditional risk factors for cardiovascular disease (CVD). Electron beam computed tomography was conducted in 1461 consecutive asymptomatic patients free of clinical CVD to determine the presence and extent of calcium in the renal arteries, coronary and non-coronary vasculature and the aortic and mitral annuli. The overall prevalence for calcium in either renal artery was 18.0%, with men having a significantly higher prevalence (20.2%) than women (15.0%) [p = 0.01]. Renal artery calcium (RAC) was significantly correlated with calcium located in the carotids, coronaries, thoracic aorta, abdominal aorta and iliac arteries and calcium in the mitral and aortic annuli (r range = 0.22-0.37). In a multi-variable model containing the traditional CVD risk factors, the presence of calcium in the renal arteries was significantly associated with age, male sex and a diagnosis of hypertension. After adjustment for these variables, the presence of calcium in the thoracic or abdominal aorta was significantly associated with RAC (OR = 2.1 and 2.0, respectively; p < 0.01 for both). The sensitivity for prevalent RAC was highest in those individuals with any calcium in the abdominal aorta (94.5%). In conclusion, calcium related to atherosclerosis in the renal arteries is highly associated with atherosclerotic calcification in other vascular beds, especially the aorta, and the valvular annuli. These relationships are independent of traditional CVD risk factors.