Study: 'White-Coat' Hypertension Isn't Harmless

Intermittent blood pressure changes can hurt heart

THURSDAY, Dec. 12, 2001 (HealthDayNews) -- "White-coat" hypertension -- the increase in blood pressure some people get at the doctor's office -- is not harmless, a new Italian study shows. People with the syndrome show signs of early heart disease, and the condition should not be ignored, the research suggests.

The study is the latest entry on a condition that continues to divide doctors. Earlier studies failed to settle the question of how to treat "white-coat" hypertension. If your pressure returns to normal when you go home, should your doctor prescribe diet, exercise and medication to treat the hypertension, or should he just continue to monitor?

"The research on 'white-coat' hypertension has indeed been conflicting," says Dr. Daniel Jones, a spokesman for the American Heart Association and associate vice chancellor for the University of Mississippi Medical Center. "There's some suggestion that it's not harmful, and it should not be treated. This study supports other evidence that it is indeed harmful and that it should be treated."

People with "white-coat" hypertension show systolic blood pressure (the higher number in a blood pressure reading) in a range of 140-180 at the doctor's office or in nervous situations, but the number falls back to normal -- below 140 -- once they get home.

Researchers, led by Dr. Anna Grandi at the University of Insubria in Varese, Italy, compared 42 patients with intermittent high blood pressure with 42 patients with high blood pressure and 42 subjects with normal blood pressure. Subjects were given echocardiograms and a heart imaging test that focused on the left ventricle, one of the blood chambers of the heart.

Compared with those with normal blood pressure, patients with "white-coat" had thicker left ventricle walls, larger hearts and increased diastolic pressure, changes that are considered early signs of heart disease. (Diastolic pressure is the pressure that develops while the heart rests and fills with blood, before the next contraction.)

The same physical changes in the heart did "not reach statistical significance" when the "white-coats" were compared to patients with sustained high blood pressure, the researchers say.

The findings appear in the current issue of the Archives of Internal Medicine.

"The research may be surprising to some, but it's not surprising," Jones says. "We know from other research that people who have left ventricular [thickening] are subject to increased risk from heart attack and stroke."

Jones says even intermittent increases in blood pressure increase the load on the heart. "It's like a blockage in a pipe, and the electrical pump works harder to pump the liquid through." Blood chemicals, like adrenaline, which are controlled by the part of the nervous system activated by emotions, also may be playing a role, Jones says.

While the new research doesn't "settle the argument," it does provide compelling evidence that doctors should consider treating patients with "white-coat" hypertension and not ignore it, says Dr. Marvin Moser, clinical professor of Medicine at Yale University and a senior consultant to the National High Blood Pressure program run by the National Institutes of Health. Moser wrote an editorial accompanying Grandi's research.

"All of the epidemiology studies that showed that people with hypertension were at greater risk for heart disease were done with blood pressure measurements taken in the office or clinic," Moser says. "And all of the clinical trials that showed that there was benefit if you treated high blood pressure used blood pressures taken in the doctor's office."

Data have shown that "people who have transient elevations of blood pressure under stress or in the office go on to develop permanent hypertension [more often] than people who don't have high blood pressure," Moser says. "Doctors should still use the causal blood pressure taken in the office or in a clinic as a guide to therapy."

What To Do

For more on high blood pressure, see the Hypertension Education Foundation or the National Heart, Lung and Blood Institute .

SOURCES: Interviews with Daniel Jones, M.D, associate vice chancellor, University of Mississippi Medical Center, Jackson; Marvin Moser, M.D., clinical professor of medicine, Yale University, New Haven, Conn.; Dec. 10/24, 2001, Archives of Internal Medicine
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