Last week my cardiologist measured the blood pressure in both of my arms. I was surprised because no doctor had ever done that before. But this is actually recommended procedure, espcially important for those with borderline or high blood pressure. Let's look at why.
Differences linked to higher disease/death risks
A meta-analysis in the January 30 online publication of The Lancet reviewed the results of 20 studies that examined the impact of differences in blood pressures in the two arms. The authors found that a difference of 15 mm Hg or more in the systolic blood pressure between the two arms was associated with a 2.5 times greater likelihood of peripheral artery disease—narrowing of arteries to the extremities, most often the legs, that can lead to intermittent claudication (leg pain when walking that is promptly relieved with inactivity). Such blood pressure differences between the two arms were also associated with a 60 percent greater risk of cerebrovascular disease (mainly strokes), cardiovascular death, and all-causes of death. In one of the studies, an inter-arm difference of 15 mm Hg or higher was found in 7 percent of people in one community.
Implications of the meta-analysis results
The early stages of peripheral artery disease generally cause no symptoms, but the disorder is progressive and can become severe enough to require amputations. A large inter-arm discrepancy in systolic blood pressure should therefore trigger a more specific diagnostic test for peripheral artery disease as well more intensive efforts to achieve better health. This includes such things as smoking cessation, and getting blood pressure and cholesterol levels under control, to slow the worsening of peripheral artery disease.
Another bad scenario would include the possibility that a diagnosis of high blood pressure could be missed if by chance a systolic blood pressure of 130 mm Hg, for example, were found in one arm while the pressure was 147 mm Hg in the other, unmeasured arm. The higher of the two blood pressures is used to make the diagnosis of hypertension.
Blood pressure measurements in both arms are recommended but rarely done
Most guidelines do recommend measuring blood pressures in both arms, especially on the first patient visit, but my own experience suggests that most doctors don’t follow the guidelines. So, at your next check-up, be sure that your doctor measures the pressure in both arms if he or she has not done so before.