by Carole Jackson, Bottom Line Health

At your annual physical, after your doctor wraps that blood pressure cuff around one of your arms, does he or she then wrap it around your other arm?

If your physician is anything like mine, then he probably doesn’t.

So what? Well, a new British study adds to the growing body of research showing that blood pressure measurements inboth arms are critical, because each arm may have a different measure—and the size of that difference can play a large role in your risk for cardiovascular problems.

THE HEART OF THE MATTER

Researchers at the Peninsula College of Medicine & Dentistry in England analyzed data from more than 20 studies on blood pressure monitoring. What they found: After five to 16 years of follow-up, researchers found that a difference of 15 mmHg of systolic pressure (the top blood pressure reading) between the two arms indicated 2.5 times the risk for peripheral artery disease…a 60% higher risk for stroke…and a 70% higher risk of dying of heart disease, compared with those whose left- and right-arm systolic pressure differed by less than 15 mmHg. And the risk for these events increased as the difference in systolic blood pressure increased over 15 mmHg.

Those particular increased risks were the same whether a patient’s two systolic numbers were, say, 115 and 100 or 170 and 155. But hypertensive patients, those with blood pressure readings over 140/90, are still at more overall risk, the researchers noted.

DOUBLE CHECKING

Here’s what had me baffled… If so many studies keep showing that the difference in blood pressure between the two arms matters, then why aren’t more doctors measuring both arms? I called lead study author Christopher E. Clark, MD, clinical academic fellow at the college, to hear his thoughts on the topic.

If your systolic pressure varies between arms, what’s likely going on? Dr. Clark said that, just like with past research, he and his coauthors suspect that there is a narrowing of the arteries (or a full-on blockage) on one side of the body compared to the other—the result of arterial disease—and that this narrowing can cause the systolic blood pressure to drop on that side.

Dr. Clark said that doctors in Europe and in the US are taught that taking blood pressure on both sides is a good idea, but it’s not mandatory in either place. In fact, fewer than half of doctors in Britain say that they regularly measure blood pressure in both arms, said Dr. Clark. He doesn’t have statistics for the US, but he speculates that the data is probably similar here. “Most doctors probably perceive taking a second measurement in the other arm as needlessly time-consuming. And, until now, the importance of doing so hasn’t been well-publicized,” he said. Hopefully, since his findings were published in January in The Lancet, the practice will become more widespread.

SPEAK UP

You could be at higher risk for cardiovascular problems than you realize. So on your next trip to the doctor, ask that your blood pressure be measured in both arms, said Dr. Clark. And in case the nurse or your doctor asks why, bring this article with you.

If you do have a dangerous difference in the measurements between arms, knowing early matters, because the sooner you are aware of your risk, the sooner you can start discussing lifestyle changes with your doctor, such as quitting smoking, exercising more and eating healthier foods—and possibly, pursuing cardiovascular medical treatment.

So don’t be shy—be a proactive patient!

Source: Christopher E. Clark, MBChB, MSc, FRCP, FRCGP, clinical academic fellow, Primary Care Research Group at the Peninsula College of Medicine & Dentistry, University of Exeter and Plymouth, England.