Round-the-clock blood pressure monitoring of nearly 900 Long Islanders has uncovered what a Stony Brook University medical investigator is calling “masked hypertension” — high blood pressure in people who had normal readings during physician visits but high blood pressure during daily routines.
High blood pressure is a chronic and treatable condition, but also widely known as a silent killer when unrecognized. The disorder significantly increases the risks for heart attack, heart failure and stroke.
Joseph Schwartz, the Stony Brook University medical researcher who made the discovery, said the new findings not only are a reversal of so-called “white coat hypertension” — high blood pressure exhibited only in clinical settings — the analysis also debunks the long-held notion of the white coat effect.
He said it’s important for doctors — and patients — to understand that blood pressure can be elevated and exceed pressure readings seen in the clinic in healthy people during a routine checkup. On the flip side, white coat hypertension does not automatically mean low blood pressure at home.
“I think we should change our thinking about white coat hypertension,” said Schawrtz, who studied more than 888 Long Islanders to upend a notion that is widely believed worldwide. White coat hypertension is also known as white coat syndrome.
“The hypertension experts have been worried about white coat hypertension since at least the 1980s,” Schwartz said.
The completed research is reported in the current issue of the journal Circulation, a publication of the American Heart Association.
Schwartz, whose studies are aimed at uncovering the causes of high blood pressure, said masked hypertension, is not only easy to miss in doctors’ offices, it can occur during the day or night.
Blood pressure readings look like a fraction with an upper and lower value. Schwartz found that 34 percent of participants had a systolic pressure — the upper number — reading 10 millimeters of mercury higher during round-the-clock monitoring than what was measured in the clinic. Ambulatory blood pressure is considered at high at 135/80 and above, he said.
He and his and colleagues had participants wear an ambulatory blood pressure monitor that fits around the upper arm and automatically measures blood pressure around the clock, even during sleep. Compared with a reading in a clinical setting, ambulatory blood pressure is recognized as a better predictor of future cardiovascular disease, Schwartz said.
Results of the research reveal 15.7 percent of participants with normal clinic readings had masked hypertension based on ambulatory monitoring, regardless of sex, race, or ethnicity. Participants were drawn from Long Island’s demographic swath — the majority were white; 7 percent black and 12 percent Hispanic. The average age was 45.
Outside of the device’s research use, Schawrtz said anyone interested in having their blood pressure monitored in this way in an effort to determine whether masked hypertension is present — or not — should contact Stony Brook University Hospital. Other doctors also are using this form of blood pressure surveillance.
“I am a big fan of 24-hour ambulatory monitoring. It’s a tool that I love using,” said Dr. Stacey Rosen, vice president of women’s health at Northwell Health’s Katz Institute for Women’s Health in New Hyde Park. She was not involved in Schwartz’s analysis.
“The importance of ambulatory monitoring is that you are not making a decision based on one reading in a doctor’s office or mini-clinic,” she said.
She said white coat hypertension is not benign and can be a sign of the chronic disorder.
Dr. Louis Morledge, an internist with Winthrop-University Hospital in Mineola and NYU Langone, said he also uses ambulatory monitoring.
“We have used these devices, the kind that go around the arm,” said Morledge, who also has a practice and is on staff at Lenox Hill Hospital, both in Manhattan.
“These devices obtain a number of values during sleep and during the day. It’s used unobtrusively,” he said.