Inter-arm blood pressure & cardiovascular events

BLOOD pressure is a widely used medical metric, but most measurements are taken using only one arm. Measuring inter-arm blood pressure involves taking two readings, one for each arm. Increased inter-arm systolic blood pressure differences are defined as 10 mmHg or greater, and while a link between inter-arm blood pressure and cardiovascular risk was suspected, little data existed to support the hypothesis until now.

A new study, the results of which were published in the March issue of The American Journal of Medicine, examined 3,390 participants aged 40 years and older from the Framingham Heart Study in the United States. All subjects were free of cardiovascular disease at baseline, but investigators found that participants with higher inter-arm systolic blood pressure differences were at a much higher risk for future cardiovascular events than those with less than a 10 mmHg difference between arms. “In this large prospective, community-based cohort of middle-age men and women free of cardiovascular disease, an increased inter-arm systolic blood pressure difference was found to be present in nearly 10 per cent of individuals and is associated with increased levels of traditional cardiovascular risk factors,” explained the lead investigator Ido Weinberg of the Institute for Heart Vascular and Stroke Care, Massachusetts General Hospital, Boston. “Furthermore, an increased inter-arm systolic blood pressure difference is associated with an increased risk for incident cardiovascular events, independent of traditional cardiovascular risk factors.”

Researchers also found that participants with elevated inter-arm blood pressure difference were older, had a greater prevalence of diabetes mellitus, higher systolic blood pressure, and a higher total cholesterol level. According to these findings, investigators suggest practitioners should consider including blood pressure readings in both arms in order to get the most accurate readings possible and to detect any differences in inter-arm blood pressure. “Even modest differences in clinically measured systolic blood pressures in the upper extremities reflect an increase in cardiovascular risk,” said Weinberg. “This study supports the potential value of identifying the inter-arm systolic blood pressure difference as a simple clinical indicator of increased cardiovascular risk.”