Blood pressure readings taken at home with approved devices can be a useful addition to blood pressure management, and may even predict cardiovascular disease (CVD) risk better than readings from the doctor’s office alone, according to a scientific statement issued today by the American Heart Association.
The Recommendations for Blood Pressure Measurement in Humans, published in Hypertension: Journal of the American Heart Association, is an update of 1993 guidelines on blood pressure measurement. While the new emphasis on out-of-office readings is the most significant change, the recommendations also emphasize using the proper cuff size when measuring blood pressure.
The most common error in measuring blood pressure in the outpatient setting is mis-cuffing, the statement says. Most mis-cuffing involves using a cuff too small for someone with large arms. Using small cuffs for children and small adults is also important.
“Since the last statement, there have been huge changes in the technology used to measure blood pressure and in our knowledge about the significance of different measurements,” said lead author Thomas G. Pickering, M.D., D.Phil., director of the Behavioral Cardiovascular Health and Hypertension Program at Columbia University Medical Center in New York.
“We’ve found that blood pressure measurements taken by doctors in their offices may actually be unreliable in many patients. For that reason, there is wider acceptance of blood pressure readings taken by patients in their homes, and of 24-hour ambulatory blood pressure monitoring.”
If there is a discrepancy between an out-of-office measurement and the office measurement, “physicians should consider the importance of the out-of-office readings if the measurement was taken in a reliable way,” Pickering said.
Ambulatory blood pressure monitoring measures blood pressure at regular intervals around the clock, while the person does normal activities and keeps an activity diary that can be compared with the measurements.
Ambulatory monitoring can also identify people with hypertension whose blood pressure stays high throughout the night, when normal levels are about 15 millimeters of mercury (mmHg) lower than during the day. Increasing evidence shows that blood pressure that does not dip at night may be associated with higher cardiovascular risk, according to the statement.
“The 1993 document didn’t say much about home and ambulatory monitoring, but now there is much more emphasis on out-of-office measurements and less exclusive reliance on traditional methods of measurement,” Pickering said. Emphasizing out-of-office blood pressure measurement does not mean that your doctor will no longer check your blood pressure, he said.
The statement encourages patients to monitor their blood pressure at home, using validated devices and providing the readings to their physicians to use as supplemental information in monitoring treatment.