Two-armed approach to vascular risk prediction

Dec 9 2013

By Eleanor McDermid, Senior medwireNews Reporter

People with different blood pressures in their left and right arms have an increased risk for cardiovascular events, even if they do not have hypertension, shows a population-based analysis.

“This study supports the potential value of identifying the inter-arm systolic blood pressure difference as a simple clinical indicator of increased cardiovascular risk,” says the research team.

Michael Jaff (Massachusetts General Hospital, Boston, USA) and colleagues showed the effect of inter-arm blood pressure on outcomes in 3390 participants of the Framingham Heart Study who had never had cardiovascular events. They were aged an average of 61 years and were followed up for an average of 13 years.

“This is the first community based cohort study to show such an association,” the researchers comment in The American Journal of Medicine. The association is consistent with previous reports showing subclavian artery stenosis as a marker for increased cardiovascular risk, they add.

The median inter-arm systolic blood pressure difference was just 3 mmHg, but 9.4% of participants had a difference of 10 mmHg or more. These people were significantly older than those with smaller inter-arm blood pressure differences, and had less favorable cardiovascular profiles, reflected in a significantly higher Framingham 10-year risk score.

They were also more likely to have hypertension, at 58.0% versus 40.6%, but their average blood pressure was within the normal range, although it was significantly higher than in people with smaller inter-arm blood pressure differences, at 136.3/76.3 versus 129.3/74.9 mmHg.

During follow-up, 26.2% of people with an increased inter-arm blood pressure difference had a first-ever cardiovascular event, compared with a rate of 17.6% in the cohort overall. Their cardiovascular risk was a significant 38% higher than that of participants without a marked inter-arm blood pressure difference after accounting for confounders including Framingham risk score.

The association held in a subgroup of 1433 patients with hypertension, and in the cohort overall when the team assessed inter-arm blood pressure as a continuous variable; each standard deviation increase conferred a 7% increase in the risk for cardiovascular events.

“Even modest differences in clinically-measured systolic blood pressures in the upper extremities reflect on cardiovascular risk,” say Jaff et al.

They conclude: “Blood pressure is easily obtained in an office setting and our findings support recommendations for measurement of blood pressure in both arms both for accurate blood pressure detection and for detection of inter-arm systolic blood pressure difference.”

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