COMBINED ASSESSMENT OF PAD
A comprehensive assessment of multiple arterial beds in CAD prediction was also reviewed. This approach may better predict CVE and the likelihood of coexisting CAD. Most studies combined data from the carotid and femoral arteries. These vascular beds lie superficially, so access is easier, faster, and can yield constructive results.
Colladenanchise et al. showed that a combined assessment of femoral bifurcation and carotid MPH was the most accurate identifier of CAD in men (AUC=0.773) 66. However, in women, the stronger indicator of CAD was achieved by a combined analysis of common femoral and carotid TPA (AUC=0.764) than height (AUC=0.659). At this value, more than half of women with false-positive stress test results were correctly identified as having no significant CAD. In another study, the authors assessed CVD risk according to the number of affected bifurcations (carotid and femoral) by ARAP 89. The presence of two carotid plaques (OR 2.21) or even one femoral plaque (OR 2.68) was associated with an increased prevalence of CVD. However, when both carotid and femoral arteries were combined the presence of plaques in three vessels was associated with a markedly increased prevalence of CVD (OR 6.48), and the presence of plaques in four vessels was associated with an even higher prevalence of CVD (OR 9.07).
The presence of plaques also in the iliac, femoral, and/or carotid arteries were shown to correlate with the presence and severity of cardiovascular disease (CVD). In 323 hypertensive patients carotid artery intima–media thickness (CCA-IMT) and carotid and/or iliofemoral (C/IF) plaques were compared according to the presence or absence of CVD90. Only C/IF plaques but not CCA-IMT, showed a positive correlation to the presence of CVD (coronary artery disease, peripheral vascular disease, cerebrovascular disease, renal artery stenosis, abdominal aortic aneurysm). C/IF plaques presented significantly greater diagnostic value than CCA-IMT for the presence of CVD (AUC, 0.78 versus 0.64) but not for 10-year risk according to Framingham equations. Khoury et al. al in CAD prediction tested a combined analysis not only of the femoral and carotid arteries but also of aortic atherosclerosis 9. They found the best sensitivity in combining aortic and femoral plaques (sensitivity 74%, specificity 79%, AUC 0,75) and the best specificity in combining aortic and carotid and femoral plaques (respectively: 59%, 84%, 0,7), both better than combing femoral and carotid plaques (respectively: 59%, 71%, 0,71).
Kafetzakis et al. in their study also assessed ultrasonic biopsy (UB) but included in this index the presence of atherosclerotic plaque in both carotid and femoral artery bifurcations 63. Carotid atherosclerotic lesions were grouped into classes according to the UB scale: I -normal intima-media thickness, II - intima degenerative changes, III - early (< 2 mm), IV - homogeneous (> 2 mm), V - heterogenous (> 2 mm), VI - multiple atherosclerotic plaque, VII - total artery occlusion. Univariate analysis showed that UB had significantly higher values in patients with obstructive CAD than in control subjects (3.94 vs. 2.65, p<0.001). ROC analysis showed that indexes yielded a significant area under the ROC curve (0.77) with a sensitivity of 69%, specificity of 70%, and cut-off value 3,25. However, IMTC was superior to UB (respectively; 0.81, 74%, 76%, 0.88).
Because of the continuing need to find the most effective method to use in clinical practice, a new Atherosclerosis Burden Score was proposed (ABS) 91. It includes the sum of the number of bifurcations of the carotid and femoral arteries with atherosclerotic plaques assessed in the US, which is similar to what was used in their study by Griffin et al. 89. ABS was highly accurate in detecting CAD (AUC=0.79) in 203 patients undergoing coronary angiography. It is superior in predictive efficacy to CCA IMT, mean/maximum carotid artery thickness, and carotid and femoral artery plaque scores in detecting CAD. CAD incidence increased from 11 % in subjects with ABS=0 to 87 % in subjects with ABS=4. By contrast, standardized C-IMT was only weakly correlated with CAD (R=0.164; P=0.02), with a 55 % occurrence in quartile 1 and 74.5 % in quartile. Table 3 summarizes the studies that showed the most significant effect of the combined PAD score on the prediction of CAD and CVD.
In their study, Lehrke et al. demonstrated potential Whole-body magnetic resonance angiography (WB-MRA) for the noninvasive assessment of almost the entire arterial vasculature within one examination92. They used the Atherosclerosis Score Index (ASI), which was generated as the ratio of summed scores to analyzable segments. The ASI was higher in patients with significant (>50% stenosis) CAD compared to patients without CAD (1.56 vs. 1.28, p=0.004). The ASI correlated with the PROCAM (R = 0.57, p < 0.001) and Framingham (R = 0.36, p = 0.01) risk scores as estimates of the 10-year risk of coronary events. A ROC-based ASI > 1.54 predicted significant CAD with a sensitivity of 59%, a specificity of 86%, and a positive predictive value of 84%.