Why you should get BP checked in both arms? Reading difference linked to higher risk of heart attack, death: Study
The next time you get your blood pressure checked, you may consider asking the physician to take it in both arms. The reason: A difference in blood pressure readings between arms is linked to a greater risk of heart attack, stroke and death, according to researchers. They conclude that the higher the blood pressure difference between the two arms, the greater is a person’s additional health risk.
According to the authors, international blood pressure guidelines currently advise health professionals to measure blood pressure in both arms when assessing cardiovascular risk, but this is widely ignored. The latest findings could lead to a change in international hypertension guidelines, meaning more at-risk patients could be identified and receive potentially life-saving treatment, they emphasize in the report published in the journal, Hypertension.
“Checking one arm then the other with a routinely used blood pressure monitor is cheap and can be carried out in any healthcare setting, without the need for additional or expensive equipment. While international guidelines currently recommend that this is done, it only happens around half of the time at best, usually due to time constraints. Our research shows that the little extra time it takes to measure both arms could ultimately save lives,” writes lead author and GP Dr Chris Clark from the University of Exeter Medical School.
Led by the University of Exeter, the global INTERPRESS-IPD collaboration -- Inter-arm Blood Pressure Difference-Individual Participant Data -- conducted a meta-analysis of all the available research. They then merged data from 24 global studies to create a database of nearly 54,000 people. The data spanned adults from the US, Europe, Africa, and Asia for whom blood pressure readings for both arms were available.
“We’ve long known that a difference in blood pressure between the two arms is linked to poorer health outcomes. The large numbers involved in the INTERPRESS-IPD study help us to understand this in more detail. It tells us that the higher the difference in blood pressure between arms, the greater the cardiovascular risk, so it really is critical to measure both arms to establish which patients may be at significantly increased risk. Patients who require a blood pressure check should now expect that it’s checked in both arms, at least once,” recommends Clark.
Cardiovascular disease is the leading cause of death worldwide, and hypertension is a major risk factor. One person dies every 36 seconds in the US from cardiovascular disease, according to the US Centers for Disease Control and Prevention (CDC). Estimates suggest that about 655,000 Americans die from heart disease each year, which is 1 in every 4 deaths.
According to the American Heart Association (AHA), high blood pressure is a “silent killer,” and most of the time there are no obvious symptoms. The AHA considers blood pressure normal when the top number is less than 120 and the bottom number is less than 80.
“Certain physical traits and lifestyle choices can put you at a greater risk for high blood pressure. When left untreated, the damage that high blood pressure does to your circulatory system is a significant contributing factor to heart attack, stroke, and other health threats,” warns the AHA.
The findings
Blood pressure rises and falls in a cycle with each pulse. It is measured in units of millimeters of mercury (mmHg), and the reading is always given as two numbers: the upper (systolic) reading represents the maximum blood pressure and the lower (diastolic) value is the minimum blood pressure. High systolic blood pressure indicates hypertension, and it is the single leading cause globally of preventable heart attacks, strokes, and deaths.
The team says a significant difference between the systolic blood pressure measurements in the two arms could be indicative of a narrowing, or a stiffening, of the arteries, which can affect blood flow. These arterial changes are recognized as a further risk marker for subsequent heart attack, stroke, or early death, and should be investigated for treatment, they explain.
For the current study, the investigators analyzed data on inter-arm blood pressure difference and tracked the number of deaths, heart attacks and strokes that occurred in the cohort over 10 years. They concluded that for each mmHg difference found between the two arms, the risk of having new angina (chest pain), a heart attack, or a stroke increased by 1% over the next 10 years. Results further indicate that differences above 5 millimeters of mercury between two arms “predict all-cause mortality, cardiovascular mortality and cardiovascular events.”
Unlike guidance in the US, both the UK and European guidelines recognize a systolic difference of 15 mmHg or more between the two arms as the “threshold indicative of additional cardiovascular risk.” The new analysis found that a “lower threshold of 10 mmHg was clearly indicative of additional risk,” which would mean that far more people should be considered for treatment if such a difference between arms is present, argue investigators. “A 10 mmHg difference in systolic blood pressure between arms should now be regarded as an upper limit of normal for systolic inter-arm blood pressure when both arms are measured in sequence during routine clinical appointments. Checking blood pressure in both arms, beyond choosing which arm to measure for the detection and management of high blood pressure, is a key part of cardiovascular risk assessment and should become routine clinical practice,” they suggest.
Professor Victor Aboyans, co-author and head of the department of cardiology at the Dupuytren University Hospital in Limoges, France, says the information should be incorporated into future guidelines and clinical practice in assessing cardiovascular risk. “It would mean many more people were considered for treatment that could reduce their risk of heart attack, stroke, and death,” emphasizes Aboyans.