Continuous Blood Pressure Monitoring Predicts Risks

Nov. 25 -- MONDAY, Nov. 24 (HealthDay News) -- Round-the-clock blood pressure measurements, especially those during the night, are better predictors of major cardiovascular problems than readings taken in a doctor's office for people whose high blood pressure is hardest to treat, a Brazilian study shows.

"Ambulatory blood pressure monitoring should be performed during the whole 24 hours, with separate analyses of the daytime and nighttime periods, because it seems that nighttime blood pressures are better cardiovascular risk factors than are daytime blood pressure," said the report in the Nov. 24 issue of Archives of Internal Medicine by physicians at the Federal University of Rio de Janeiro.

The researchers followed 556 people with what doctors call "resistant hypertension" -- blood pressure that remains dangerously high despite standard drug therapy. More than 10 percent of people with high blood pressure are in that category, the report said.

Some of the participants in the Brazilian study underwent usual regular blood pressure measurements in a doctor's office, while others had continuous monitoring at home (ambulatory monitoring) -- every 15 minutes during the day and every 30 minutes at night.

The clear and present danger of high blood pressure was evidenced by the high incidence of strokes, heart attacks, heart failure and deaths, which occurred in 19.6 percent of the study group, with an average follow-up period of 4.8 years. Office blood pressure measurements did not predict any of these events, whereas higher round-the-clock readings did, the report said.

The report is yet another instance of a common heart test failing to predict trouble ahead. A study reported earlier this month by physicians at the London Chest Hospital in England found that performing an electrocardiogram, the standard test for measuring the activity of the heart, is of little use in forecasting future coronary problems for people with chest pain.

On the hypertension front, previous studies have indicated that "ambulatory blood pressure measurements do predict things better, in part because they are so frequent," said Dr. William C. Cushman, professor of preventive medicine and medicine at the University of Tennessee.