Etiopathogenic differences in coronary artery disease and peripheral artery disease: Results from National Health and Nutrition Examination Survey (NHANES) 1999-2004

Introduction: Although coronary artery disease (CAD) and peripheral artery disease (PAD) represent systemic atherosclerosis, there are hemodynamic, anatomic and physiologic differences between the two vascular beds. We aimed to determine etiopathogenetic differences between CAD and PAD, using a large representative national database.

Methods: Cross-sectional data from NHANES 1999-2000, 2001-2002 and 2003-2004 were merged. History of CAD was determined using standardized questionnaire. PAD was defined as ankle brachial pressure index<0.9. Multivariate logistic regression technique with survey weights was utilized for analysis. Results: In comparison to CAD, a significantly greater proportion of individuals with PAD were females (65% versus 41%), blacks (16% versus 7%) and active smokers (30% versus 24%). After adjustment for demographic and clinical characteristics, patients with PAD had significantly higher serum concentrations of LDL-cholesterol, triglycerides and C-reactive protein (CRP). Amongst the active smokers, the risk of PAD [OR(95%CI):2.82(2.20-3.61)] was observed to be significantly higher than the risk of CAD [OR(95%CI):1.60(1.10-2.34)]. The risk of CAD increased with cotinine levels >0.02ng/mL. However, the risk of PAD increased only with cotinine levels >138 ng/mL. With respect to CRP, the risk of CAD and PAD tended to increase with CRP>0.25mg/dL. However, the risk of PAD was significantly higher than the risk of CAD with increasing CRP levels.

Conclusions: CAD and PAD differ with respect to several characteristics including gender, race, smoking status, serum LDL and triglycerides and CRP concentrations. Relationship between PAD and serum cotinine demonstrated a threshold phenomenon. The risk of PAD was significantly increased only with cotinine>138ng/mL.