Researchers found that a difference of 15 points or more in the readings between the left and right arms raised the risk of peripheral vascular disease, a narrowing or blockage of the arteries, by two-and-a-half times.
That same 15 point-difference in systolic readings (the top number in a blood pressure reading) also increased the risk of cerebrovascular disease by 60%. Cerebrovascular disease is associated with thinking problems, such as dementia, and an increased risk of stroke.
Researchers say the results suggest that doctors should routinely compare blood pressure readings from both arms to prevent unnecessary deaths.
Although the practice of taking blood pressure from both arms as a part of heart disease screening has been adopted in Europe, and some guidelines in the U.S. recommend it, American Heart Association spokesman Richard Stein, MD, says it’s not routinely done in the U.S.
“This is very interesting,” says Stein, professor of cardiology at the New York University School of Medicine. “It can translate immediately, as we learn more about it, into better detection of people at higher risk of disease.”
Is 2 Better Than 1 for Blood Pressure?
In the study, British researchers examined 20 studies covering differences in systolic blood pressure — the pressure of blood in arteries when the heart is contracting — between arms.
The results, published in The Lancet, showed that a difference of 15 points or more in the systolic readings between the left and right arms was associated with an increased likelihood of several heart-related risks, including:
- The risk of peripheral vascular disease was two-and-a-half times higher.
- The risk of cerebrovascular disease was 60% higher.
- The risk of dying from heart and circulatory diseases rose by 70%.
The risk of peripheral vascular disease was also higher when there was a difference in blood pressure readings of 10 points or more.
“Findings from our study should be incorporated into future guidelines for hypertension and blood-pressure measurement … to promote targeted screening for peripheral vascular disease and aggressive risk factor management,” write Christopher Clark, MD, of the Peninsula College of Medicine and Dentistry at the University of Exeter, and colleagues.
More Research Needed
Commenting on the research, Natasha Stewart, senior cardiac nurse at the British Heart Foundation, says in an emailed statement: “Theoretically, measuring blood pressure on both arms to assess vascular disease risk is a quick and simple task. But it’s too early to say whether this idea could become part of standard health care practice and so we need more research to confirm the findings.”
“It’s very important that other risk factors, apart from high blood pressure, are taken into account to establish whether doctors need to take a closer look at someone’s heart disease risk,” she says.
In an editorial that accompanies the study, Richard McManus, MD, of the University of Oxford, and Jonathan Mant, MD, of the University of Cambridge write that more research is needed to clarify whether differences in blood pressure readings justify the preventive measures suggested.
“Overall, Clark and colleagues’ systematic review and meta-analysis support existing guidelines stating that blood pressure should be measured in both arms,” they write. “Ascertainment of differences should become part of routine care, as opposed to a guideline recommendation that is mostly ignored.”