The epidemiology of subclavian stenosis and its association with markers of subclinical atherosclerosis: the Multi-Ethnic Study of Atherosclerosis (MESA)

Background: Recent studies indicate that subclavian stenosis (SS), diagnosed by a large systolic blood pressure difference (SBPD) between the right and left brachial arteries, is associated with cardiovascular disease (CVD) risk factors and outcomes. We sought to describe the epidemiology of SS and determine its association with markers of subclinical CVD in the baseline cohort of the Multi-Ethnic Study of Atherosclerosis.

Methods: We defined SS by an absolute SBPD>or=15 mmHg. Peripheral artery disease (PAD) was defined by an ankle-brachial index<or=0.90. The coronary artery calcium score (CAC) and the common carotid artery intima-media thickness (CCA-IMT) were measured by computed tomography and B-mode ultrasound, respectively. Odds ratios for the associations of SS with risk factors and subclinical disease were estimated using logistic regression.

Results: Of 6743 subjects studied, 307 participants (4.6%) had SS, with a higher prevalence in women (5.1%) than men (3.9%), and in African Americans (7.4%) and non-Hispanic whites (5.1%) than Hispanic (1.9%) or Chinese (1.0%) participants (p<0.01). In a model including age, gender, ethnicity, traditional and novel CVD risk factors, significant associations with SS were observed for C-reactive protein (highest vs. three lower quartiles: OR=1.41; 95%CI: 1.06-1.87) and brachial artery pulse pressure (OR=1.12/10 mmHg; 95%CI: 1.03-1.21). Adjusted for age, gender, ethnicity, traditional and novel CVD risk factors, SS was significantly associated with PAD (OR=2.35; 1.55-3.56), with CCA-IMT (highest vs. the lower three quartiles: OR=1.32; 1.00-1.75), and high CAC (score>100 vs. score=0; OR=1.43; 1.03-2.01).

Conclusions: The subclavian stenosis is positively associated with other markers of subclinical atherosclerosis.