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%.