ambulatory blood pressure

A new study indicates that traditional methods of measuring blood pressure may not provide sufficient information to prevent premature death.

When the heart beats, it contracts, pushing blood through your arteries to the rest of your body. This creates pressure in the blood vessels. The amount of pressure in your arteries is called your systolic pressure. The pressure in your arteries when your heart is between beats is called your diastolic pressure.

When you have your blood pressure measured, it is expressed as a fraction with the systolic pressure on top and the diastolic pressure on the bottom. Both numbers are important in assessing the health of your heart. Numbers higher than 120/80 are an indication that your heart is working too hard to pump blood to the rest of your body.

An individual is generally diagnosed with hypertension, or high blood pressure, when their blood pressure measures are higher than 140/90.  Obtaining an accurate measure of blood pressure is critical because individuals with hypertension are at increased risk of heart disease, stroke, and death. Worldwide, hypertension is the leading cause of premature death and disability.

How do we currently measure blood pressure?

Typically, diagnosing hypertension involves the use of a blood pressure cuff fastened around the upper arm to measure a person’s blood pressure in a clinic or doctor’s office.  However, in-office blood pressure measures can appear normal, even if the person’s overall blood pressure is elevated.  This is referred to as “masked” hypertension.

Alternatively, due to the stress or worry of being in a medical office, a person’s blood pressure can appear to be high, even if their overall blood pressure levels are normal.  This is referred to as “white coat” hypertension. Either case can cause healthcare professionals to misidentify and treat hypertension, which can lead to higher patient risk for cardiovascular events, stroke, and death.

Is there a better way to identify hypertension and prevent premature deaths?

There is another way to measure blood pressure. Ambulatory blood pressure (ABP) monitoring involves using an oscillometric device to measure a person’s blood pressure every 20 minutes during the day and every half hour during the night over the course of a 24-hour period of time.

In a recent study published in New England Journal of Medicine, Spanish researchers compared in-office blood pressure (BP) monitoring to 24-hour ambulatory blood pressure (ABP) monitoring to see which was more effective at identifying hypertension and cardiovascular mortality.

The researchers analyzed data from a registry of nearly 64,000 adult, Spanish patients with hypertension who had been recruited between 2004 and 2014.  Each participant had their blood pressure measured in-office, and again, for 24-hours with ABP monitors.

Ambulatory blood pressure monitoring predicted mortality better than in-office measurements

During a follow-up (median 4.7 years), they found that 2,513 people had died from any cause and an additional 1,295 people had died from cardiovascular disease. The research team found that ABP monitoring predicted cardiovascular and general mortality much better than in-office BP measurements.

Surprisingly, they found that masked hypertension was the most strongly associated with mortality.  In addition, even white coat hypertension was associated with a higher risk of mortality compared to those with normal BP. This study suggests that ABP monitoring is more informative than in-office BP measures and should be used to improve the diagnosis and treatment of hypertension.

Written by Debra A. Kellen

Reference:  Banegas, J. R., Ruilope, L. M., de la Sierra, A., Vinyoles, E., Gorostidi, M., de la Cruz, J. J., … & Williams, B. (2018). Relationship between clinic and ambulatory blood-pressure measurements and mortality. New England Journal of Medicine378(16), 1509-1520.   DOI: 10.1056/NEJMoa1712231

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