You may have heard of the phenomenon "white-coat hypertension," which describes people who only experience high blood pressure in the doctor's office. The issue has drawn so much attention that Britain's National Institute for Health and Clinical Excellence started recommending that all patients suspected of having hypertension in the doctor's office (a reading of 140/90 mmHg or higher) should wear a device called an ambulatory blood pressure monitor (ABPM for 24 hours to see if the high blood pressure diagnosis is the real thing.
The question is why aren't doctors in the US already routinely using this device?
Readings Around The Clock
Hypertension specialist and ABPM expert George Bakris, MD, director of the Hypertension Center at The University of Chicago Medical Center, said that the monitor provides doctors with invaluable health information. "Blood pressure is variable throughout the day in all of us," he said, "and it is the extent of the variability that causes hypertension and helps predict risk for stroke and other cardiovascular problems. We can't know what that variability is without information from a 24-hour monitor." The ABPM also can reveal the following…
- Masked hypertension. Doctors have identified this problem, which is essentially the opposite of white-coat hypertension, in just the last decade. Let's say that there's a person who doesn't have a stressful life, but he happens to have a stressful job, which causes his blood pressure to soar to dangerous levels in the middle of the day. Readings at a doctor's office may not reveal this, so this condition is called "masked hypertension," and it's potentially fatal. So doctors may soon require certain patients with normal readings in the doctor's office to use the ABPM.
- Hyper-dipping. At night, blood pressure normally settles into lower numbers, but some people are "hyper-dippers." That means that their blood pressure sinks far below normal and puts them at risk for stroke and other cardiac events-possibly because their blood flow isn't strong enough to get through the vessels that feed the heart if they are blocked, Dr. Bakris said.
- Non-dipping. Then again, some people are "non-dippers," meaning that their blood pressure fails to fall at night. This also increases the risk for stroke or other cardiac events. A nondipper might be able to avoid this danger with judicious use of medication taken at bedtime.
How It Works
The ABPM is made up of two elements—a waist device with tubes leading up to an upperarm cuff that can be programmed to automatically inflate every 15 to 30 minutes during the day and once an hour at night. This pattern of inflation may be annoying for light sleepers, but doctors need at least six nocturnal readings to get an accurate picture and, as Dr. Bakris noted, one night's discomfort is a small price to pay for (potentially) a lifetime of better health.
What Does The Future Hold?
Right now in the US, these ABPM devices are used only by hypertension specialists-doctors who are specially trained to interpret the readings accurately. Some private US insurers and Medicare are beginning to recognize the value of the ABPM and cover at least some of the cost of the monitoring, But until these devices become cheaper to use and until more general practitioners are trained to use them, it's unlikely that you'll be able to request an ABPM at a doctor's appointment anytime soon.
But, in the long run, the monitor would likely save the health-care system money by curtailing unnecessary and risky treatment for people who don't need it and preventing stroke and other cardiac events in people whose blood pressure is silently but surely putting them at risk.
For an accurate blood pressure reading, empty your bladder because a full bladder can affect the reading. Avoid smoking, drinking anything caffeinated and exercising 30 minutes before the test. Keep your feet flat on the floor for five minutes prior to checking your blood pressure. During the reading, keep still and rest your arm on a table so that it is at heart level.
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