Clinical evaluation of plasma high-density lipoprotein subfractions (HDL2, HDL3) in non-insulin-dependent diabetics with coronary artery disease.

STATEMENT OF THE PROBLEM: Low levels of high-density lipoprotein cholesterol (HDL-C) have a strong association with coronary artery disease (CAD) in patients with non-insulin-dependent diabetes mellitus (NIDDM). In this study, we tried to evaluate whether one or both of the major HDL subclasses (HDL2, HDL3) is strongly associated with the risk of CAD in NIDDM subjects. METHODS: The separation of HDL subclasses was carried out by ultracentrifugation in a Beckman Airfuge. HDL2 subclass was isolated from the supernatant and its cholesterol content was measured enzymatically. Plasma HDL3 cholesterol was calculated as the difference between results for total HDL cholesterol and HDL2 cholesterol. RESULTS: NIDDM patients with CAD had significantly higher triglyceride levels compared to either control (217.09+/-55.04 versus 89.62+/-31.29 mg/dl, P=.001) or CAD patients without NIDDM (217.09+/-55.04 versus 156.28+/-46.39 mg/dl, P<.05). However, in the diabetic patients with CAD, there was a statistically significant decrease in HDL cholesterol (39.63+/-8.59 versus 55.86+/-13.49 mg/dl, P<.01), HDL2 cholesterol (8.74+/-3.28 versus 16.95+/-5.73 mg/dl, P<.001), and HDL3 cholesterol (31.23+/-7.41 versus 38.91+/-8.93 mg/dl, P<.05) in comparison to nondiabetic controls. Moreover, in the comparison between non-insulin-dependent diabetics with CAD and CAD subjects without NIDDM, HDL cholesterol (39.63+/-8.59 versus 46.13+/-6.33 mg/dl, P<.05) and HDL2 cholesterol (8.74+/-3.28 versus 11.84+/-4.01 mg/dl, P<.02) were significantly reduced, while HDL3 cholesterol levels were (31.23+/-7.41 versus 34.29+/-7.94 mg/dl, P=.92) unaltered. Additionally, the percentage reduction of cholesterol in HDL2 fraction was proportionately greater than the decrease in HDL3 subclass in both comparisons. Moreover, in NIDDM with CAD, HDL cholesterol was reduced by 29% and 14%, HDL2 cholesterol by 48% and 26%, and HDL3 cholesterol by 20% and 9%, compared relatively to controls and CAD subjects without NIDDM. CONCLUSIONS: In conclusion, HDL2 is the more variable subclass and reflects changes in HDL. This suggests that the protective role of total HDL against CAD is mainly mediated through HDL2 fraction. Therefore, HDL2 might be a better predictor of coronary heart disease than total HDL, in non-insulin-dependent diabetes mellitus.

Ankle-brachial index as a predictor of the extent of coronary atherosclerosis and cardiovascular events in patients with coronary artery disease.

Resting ankle-brachial pressure index (ABI) is a noninvasive method to assess the patency of the lower extremity arterial system. This study aimed to examine the relation between ABI and the extent of coronary atherosclerosis, the extracoronary atherosclerosis lesions, and the prognosis of patients referred for elective coronary angiography. One hundred sixty-five consecutive patients underwent coronary angiography, ultrasound imaging for intima-media thickness measurement of carotid and femoral arteries and ABI evaluation; subjects were followed up for 14.5 +/- 2.4 months. With regard to vascular risk factors, only smoking (p = 0.025) and diabetes (p = 0.01) were related to ABI in the multiple regression analysis. ABI was independently and inversely related to carotid bifurcation (p = 0.0002) and common femoral artery intima-media thickness (p = 0.018). ABI was related to the extent of coronary artery disease as measured by number of coronary arteries diseased (analysis of variance, p = 0.04) and Gensini angiographic score (p = 0.01). In the follow-up study ABI < 0.90 was a univariate predictor of cardiovascular events (cardiac death, nonfatal myocardial infarction, unstable angina) and revascularization procedures. The estimated cumulative rate free of cardiovascular events was 90% for ABI > 0.90 and 73% for ABI < 0.90 (p = 0.02). In logistic regression analysis, ABI < 0.90 was an independent predictor for cardiovascular events after adjustment for age, low-density lipoprotein cholesterol, carotid and femoral intima-media thickness, and Gensini score. Further adjustment for the confounding effect of insulin weakened the relation between ABI and cardiovascular events (p = 0.1). In conclusion, ABI is a simple index related to the extent of atherosclerosis in coronary and noncoronary arterial beds, reflecting generalized atherosclerosis. ABI could be useful in assessing the risk for cardiovascular events in patients with coronary artery disease.

Atherosclerotic changes of extracoronary arteries are associated with the extent of coronary atherosclerosis.

The aim of the present study was to examine the association between carotid and femoral artery intima media thickness (IMT) and the extent and severity of coronary artery disease (CAD) as well as the effects of traditional vascular risk factors on the atherosclerotic changes in the carotid and femoral arteries. Two hundred twenty-four patients who underwent coronary angiography for suspected CAD were evaluated by B-mode ultrasound imaging of the common carotid, internal carotid, carotid bifurcation, and femoral artery for measurement of IMT; traditional vascular risk factors were also evaluated in these patients. CAD extent was evaluated by the number of diseased vessels and by Gensini score. Age, male gender, and diabetes were common risk factors for higher CAD extent and higher carotid and femoral IMT. Insulin levels were correlated with femoral IMT and CAD extent, whereas blood lipids were correlated predominantly with carotid IMT. IMT from carotid and femoral arteries increased significantly with an increase in CAD extent. Using multiple stepwise regression analysis, the following parameters were found to be independent predictors of CAD extent: male gender (p<0.0001), common femoral artery IMT (p = 0.0028), common carotid artery IMT (p = 0.015), age (p = 0.02), diabetes mellitus (p = 0.035), and carotid artery bulb IMT (p = 0.04). Common femoral IMT was the only independent parameter for predicting Gensini score (p<0.0001). In conclusion, there are territorial differences in the various arterial beds regarding their response to risk factors. Femoral artery and carotid bulb are independent predictors of CAD extent and the inclusion of these measurements would add information to that provided by the common carotid artery.