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IN-OFFICE PULSE PRESSURE APPEARS TO PREDICT PATIENTS WITH WHITE COAT HYPERTENSION
Researchers Optimistic that a Simple Test Can Help Reduce Over-Treatment
New Orleans, LA – New data suggest that measuring pulse pressure – the change in blood pressure seen during a contraction of the heart – may offer clinicians a simple test to help identify patients with the “white coat” effect and improve care, according to research presented today at the American College of Cardiology’s 60th Annual Scientific Session. ACC.11 is the premier cardiovascular medical meeting, bringing together cardiologists and cardiovascular specialists to further advances in cardiovascular medicine.
Anxiety from going to the doctor can result in a white coat effect (WCE) – when blood pressure measured in the doctor's office is higher than it might be at home or in other settings – in some cases. In fact, it is estimated that anywhere from 20 to 50 percent of patients could experience a WCE, which may result in unnecessary treatment with blood pressure lowering medications.
Although earlier studies demonstrated that elevated systolic blood pressure (SBP) is related to the WCE, this is the first to look at whether pulse pressure can help separate white coat hypertension from true hypertension. Compared to SBP, pulse pressure (measured as the systolic pressure minus the diastolic pressure) was found to be more significantly related to WCE. Researchers also found that nearly one in three patients being treated for high blood pressure actually had WCE, which appears to be more likely among those with a family history of early heart disease.
“Elevated blood pressure in the clinical setting does not mean that a patient has hypertension entirely,” said Youngkeun Ahn, M.D., Chonnam National University Hospital, Gwangju, South Korea, and lead investigator of the study on behalf of Korean Hypertension Research Network. “Sometimes it is white coat effect that needs to be looked for, and there are very few clinical hints as to its presence. Even though 24-hour ambulatory blood pressure monitoring or self monitoring is useful for the diagnosis of white coat effect whenever clinical suspicion is raised, pulse pressure seems to be a simple parameter for suspicion of white coat effect in people without aortic valvular insufficiency or aortic disease. If we detect it more easily, we can avoid some over-treatment of these patients.”
A total of 1,087 outpatients from university hospital settings who had chronically treated hypertension were enrolled in the study. Participants were taught how to properly measure their blood pressure and then checked and recorded it at home every morning and evening for two weeks. Researchers defined WCE as a positive difference between a blood pressure reading in the physician’s office and that measured at home. They also evaluated the relationship of WCE with age, gender, potential vascular risk factors, target organ damage, systolic and diastolic blood pressure, average blood pressure, heart rate, and pulse pressure.
White coat hypertension was found in 31 percent of patients. In the analysis, pulse pressure was positively correlated with systolic WCE (p<0.001) and diastolic WCE (p<0.001). The presence of WCE was defined as a difference above 20 mmHg in systole or 10 mmHg in diastole. The averages of WCE were 9.8±14.8 mmHg in systole and 3.4±9.2 mmHg in diastole.
“Based on our findings, if a patient has an elevated blood pressure reading in the clinic along with elevated pulse pressure, we can consider white coat effect before recommending anti-hypertensive agents,” Ahn said, and explained that he and his team were interested in determining what factors are associated with WCE in treated hypertensive patients in Korea.
Elevations of blood pressure in the doctor’s office did not appear to be associated with age or gender. Patients with a family history of premature heart disease were more likely to have a WCE, while those with diabetes, smokers or people with organ damage in the heart, brain, kidney, peripheral artery, retina, or carotid artery were less likely to be effected.
“The positive relationship with family history might be a result from the effects of anxiety and emotional stress,” Ahn added. “The negative relationship with diabetes or smoking means that the WCE was relatively benign in these patients.”
There is some evidence that white coat hypertension might signal that someone is at risk of developing high blood pressure in the future, so many patients still need to be monitored. Ahn said future studies should evaluate the long-term follow-up data to assess the prognostic value of pulse pressure on WCE.
This study was funded by the Korean Institute of Medicine, Korea and the Korea Healthcare Technology R&D Project, Ministry of Health, Welfare & Family Affairs, and the Republic of Korea.
Dr. Ahn will be available to the media on Sunday, April 3 at 1:00 p.m. CDT in Room 338/339.
Dr. Ahn will present “Can Pulse Pressure Predict White Coat Effect in Treated Hypertensive Patients?” on Monday, April 4 at 9:30 a.m. CDT in Hall F of the Ernest N. Morial Convention Center.
The American College of Cardiology (www.cardiosource.org) represents the majority of board certified cardiovascular care professionals through education, research, promotion, development and application of standards and guidelines – and to influence health care policy. ACC.11 is the largest cardiovascular meeting, bringing together cardiologists and cardiovascular specialists to share the newest discoveries in treatment and prevention, while helping the ACC achieve its mission to address and improve issues in cardiovascular medicine.