Role of ankle-brachial pressure index as a predictor of coronary artery disease severity in patients with diabetes mellitus.

Background: Previous studies have reported a close correlation between low ankle-brachial pressure index (ABPI) and various cardiovascular risk factors. However, despite the well-established potential hazards of consequent coronary artery disease (CAD), no data exist on the relationship between ABPI and the severity of CAD, particularly in patients with diabetes mellitus (DM).
Methods: A total of 840 patients ranging from 35 to 87 years of age (mean [+/- SD] 63.9+/-10.2 years) with suspected CAD in a clinical practice were enrolled. All patients underwent ABPI measurements and coronary angiography. Patients were divided into four groups according to the results of ABPI measurements and the presence or absence of DM: group A had an ABPI value of at least 0.9 but no DM (A-/D-); group B had an ABPI value of at least 0.9 and DM (A-/D+); group C had an ABPI of less than 0.9 but no DM (A+/D-); and group D had an ABPI value of less than 0.9 and DM (A+/D+).
Results: Age was significantly higher in the A+ (groups C and D) than the A- patients (groups A and B). Moreover, men predominated in all four groups. Comparisons of sex distribution among the four groups revealed that group D had the highest percentage of women, while group A had the lowest. Total cholesterol level did not differ among the four groups, although group D tended to have the highest result. Patients in group D had the highest percentages of hypertension, hypercholesterol, hypertriglyceride, low high-density lipoprotein cholesterol and high low-density lipoprotein cholesterol among the four groups. Group D exhibited the highest triglyceride and uric acid levels, the lowest high-density lipoprotein cholesterol level, and the highest metabolic syndrome criteria number and percentage of metabolic syndrome. Furthermore, group D had the highest mean lesion numbers, mean numbers of target vessel involvement, stenoses with type C classification and complex morphology lesions (chronic total occlusion, diffuse or calcified lesions) among the four groups. There were still significant differences in lesion numbers (P<0.001) and numbers of target vessel involvement (P<0.001) for ABPI predicting CAD severity after controlling for the effects of DM and age. The sensitivity, specificity, positive predictive value and negative predictive value of using an ABPI of less than 0.9 to predict CAD differed significantly between patients with and without DM.
Conclusions: ABPI is a useful noninvasive tool for predicting CAD severity, even in patients with DM.