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As reported by the New Haven Register, April 12, 2004.

Pressure Cuff, 1 Reading, Not Exact Enough

Thereís more to blood pressure than meets the sphygmomanometer.

By Abram Katz

Thatís the traditional inflated pressure-cuff-around-the-arm apparatus ó and itís not quite good enough, according to a professor at the University of Connecticut School of Medicine.

The instrument works fine, measuring pressure in the large brachial artery between shoulder and elbow.

But one reading really isnít enough, said Dr. William B. White, chief of the division of Hypertension and Clinical Pharmacology at UConn.

"Blood pressure in the doctorís office is insufficient," he said.

White said blood pressure must be gauged over a 24-hour period because it rises when the patient is awake and drops during sleep.

"About 22 years ago, I started developing and working with monitors that measure blood pressure over 24 hours," White said.

The monitors inflate cuffs and take readings about 100 times in a day.

"Iíve done thousands of blood pressure measurements, and I saw new diagnoses," White said.

For example, White found that some people maintain waking pressure even when they are asleep, when pressure normally drops.

He also found certain patients with excessive variability of blood pressure. Others show a spike of high readings in the morning.

These all suggest impending heart problems, White said.

Meanwhile, 20 to 35 percent of patients display the "white coat" effect. Anxiety at having their blood pressure measured actually elevates the numbers.

"If a middle aged patient has a blood pressure of 140/100, a doctor will recommend anti-hypertension medication," White said.

"I would recommend a 24-hour measurement," he said.

The two numbers in the measurement represent the pressure in the artery when the heart pumps blood over the pressure between beats.

The top number is called the systolic pressure and the bottom one is diastolic. A 120/80 reading is considered normal.

Sphygmomanometers work by exerting enough pressure on the artery to block flow. The measurer slowly releases pressure from the cuff while listening with a stethoscope and looking at a column of mercury or a dial that displays pressure.

When the cuff pressure equals the systolic pressure, blood starts to flow, producing a certain sound. At a lower pressure, the diastolic pressure creates another sound.

Mechanical monitors do the same job, recording results for later downloading into a computer.

White said the "white coat" effect can add 20 to 50 points to the systolic pressure and 10 to 30 points to the diastolic.

Results from 24-hour monitors reveal that blood pressure surges for two to three hours after awakening.

During the next eight to nine hours of work, the pressure bounces around. Work, stress, medications and sleep are all factors.

At night, during sleep, pressure drops 20 to 30 percent, White said.

People who are hypertensive at work should be treated, he said. These cases would have otherwise been missed.

When pressure does not drop during sleep it is an "ominous" sign, White said, apparently signaling a higher risk for heart attack and stroke.

People with numbers that rise and fall sharply seem more likely to suffer a cardiac event, White said.

About 10 to 20 percent of people with hypertension show a big morning spike of 35 to 40 points, which significantly increases the chance of stroke, he said.

Why pressure surges in these patients is not clear.

White said that the half-dozen classes of blood pressure medications, including diuretics, to beta-blockers, calcium channel blockers, and ACE inhibitors, are effective.

Cholesterol-lowering drugs, such as Lipitor, can also significantly reduce the risk of cardiovascular disease, White said.

None of this equipment or medications matters unless a person gets his blood pressure tested regularly and sufficiently, White said.