Under-Recognized Condition Important In Treatment of High Blood Pressure

An under-recognized and usually asymptomatic condition called subclavian artery stenosis – an obstruction of arteries located under the clavicle, or collarbone – is important in the diagnosis and treatment of high blood pressure, according to a study by researchers at the University of California, San Diego (UCSD) School of Medicine and Northwestern University’s Feinberg School of Medicine in Chicago.

Published in the August 4, 2004 issue of the Journal of the American College of Cardiology, the study investigated the prevalence of subclavian artery stenosis (SS) in 4,223 individuals, and determined risk factors.

SS was found in approximately 2 percent of individuals without cardiovascular problems and in 7 percent of those currently under a doctor’s care for cardiovascular conditions. Patients most at risk were those with current or past smoking histories, higher than normal systolic blood pressure, lower levels of HDL cholesterol, and the presence of peripheral arterial disease (PAD), which is characterized by narrowing of the arteries in the legs and arms due to build-up of atherosclerotic plaque on vessel walls. Patients with PAD were found to be at a fivefold greater risk of having SS.

Michael H. Criqui, M.D., M.P.H., UCSD School of Medicine professor of family and preventive medicine and one of the study’s primary authors, noted that bilateral arm blood pressure measurements should routinely be performed in patients with an elevated risk profile, both to screen for SS and to avoid missing a hypertension or PAD diagnosis. A PAD diagnosis is made using blood pressure measurements from both the arm and the ankle.

In addition to Criqui, the study included first author Ramin Shadman, B.A., a fourth year UCSD medical student; Mary M. McDermott, M.D., Feinberg School of Medicine, Northwestern University; Warner P. Bundens, M.D. and Arnost Fronek, M.D., UCSD Department of Surgery; and Julie O. Denenberg, M.A. and Anthony C. Gamst, Ph.D., UCSD Department of Family and Preventive Medicine. The study was funded by the National Institutes of Health, and the UCSD Stein Institute for Research on Aging.