The correlation between the severity of peripheral arterial disease and carotid occlusive disease

Peripheral arterial disease (PAD) and carotid occlusive disease (COD) are b oth known to be specific manifestations of atherosclerosis. Because they bo th have a common cause, it is reasonable to hypothesize that they should co rrelate with each other to a certain extent, and previous studies have show n that there is a correlation between the prevalence of PAD and COD. The pu rpose of this study was to determine whether a correlation exists between t he severity of PAD and the severity of COD by retrospectively looking at a group of 203 patients who underwent non-invasive testing for suspicion of P AD at the San Diego VA Hospital or UCSD Medical Center, and who also had a non-invasive duplex carotid scan. The severity of PAD was assessed by segme ntal blood pressure ratios (leg segment/arm ratio) in each leg taken at the toe, ankle, and below the knee, as well as the peak flow velocity of the p osterior tibial artery. The severity of COD was assessed by duplex ultrasou nd scans of six distinct segments of the carotid artery system: the right a nd left common, internal, and external carotid arteries. Correlation analys is showed r = 0.23 (p = 0.001) when comparing a PAD aggregate standard scor e with the number of diseased carotid arteries (>50% stenosis), and r = 0.2 3 (p = 0.001) when comparing a PAD aggregate standard score with an average COD score. Because about 50% of the patients had undergone surgical interv ention on their leg or carotid arteries, another correlation analysis restr icted to patients with no surgical interventions (n = 97) was performed. Th e above correlations were slightly attenuated in this analysis, r = 0.21 (p = 0.043) and r = 0.17 (p = 0.092), respectively. The results indicate that there is a modest but significant correlation between the severity of PAD and the severity of COD in a population with a high prevalence of both.