Extending the Reach of Ambulatory Blood Pressure MonitoringMasked and Resistant Hypertension

Abstract

A mbulatory blood pressure (BP) monitoring is very gradually finding its way into everyday clinical practice. However, the only clinical indication approved for reimbursement in the United States so far is suspected white coat hypertension, defined by the Centers for Medicare and Medicaid Services (CMMS) in 2001 as the combination of elevated clinic blood pressure (BP) and at least two readings taken outside the clinic that are in the normal range.1 In addition there must be no evidence of target organ damage. Another indication considered was the evaluation of patients with apparently resistant hypertension. At that time there was only one study, by Redon et al, 2 that had used ABP to evaluate prognosis in this group; that study had found that about one third of those patients whose clinic BP remained obdurately high despite taking three or more antihypertensive drugs were at low risk of morbid events during a 3-year follow-up period. These patients were identified by low ambulatory BP. The CMMS committee decided to reject this indication on the grounds that it rested on the findings of a single study.The initial prognostic studies using ABPM have largely focused on the identification of patients who are at lower cardiovascular risk than would be suspected from their clinic BP, 3 particularly those with white coat hypertension. Whether these patients should be given antihypertensive medications remains controversial, but there is no evidence that this would benefit them. The CMMS decision was based on the assumption that most patients with white coat hypertension would not be started on drugs. More recent studies, of which the study by Pierdomenico et al 4 in this issue of the Journal is a good example, have extended the scope of ABPM in two directions: first, by applying it to patients in whom hypertension is already diagnosed and treated; and second, by identifying another group of patients in whom a normal clinic BP significantly underestimates the risk. This group has been variously labeled with the terms "reverse white coat hypertension" and "white coat normotension"; but we preferred to call it "masked hypertension" on the grounds that such patients looked like truly hypertensive patients except for their normal clinic BP-that is, they had elevated BP during the day and evidence of target organ damage. 5The Pierdomenico study is of particular interest because it investigated a group of treated patients who were being followed in a hypertension clinic, some of whom appeared to have good BP control whereas others did not. Each of these two groups could be subdivided into two subgroups according to whether the ambulatory BP was controlled or not controlled. The first disturbing finding was that of the total 742 patients, only 470 (63%) were classified as having controlled or uncontrolled BP by both criteria. Thus if it is accepted that ABP predicts risk better than clinic BP, approximately one third of the patients attending this clinic were misclassified by their clinic BP. Of the patients who had normal cl...

Home versus ambulatory blood pressure monitoring in the diagnosis of clinic resistant and true resistant hypertension

“…1,2 Studies have shown that a significant white-coat effect is as common in patients with RH as in the general hypertensive population, with prevalence ranging from 20 to 30%. 1,3 Furthermore, using only conventional clinic blood pressure (CBP) measurements as follow-up method, patients with masked RH 4 cannot be detected, antihypertensive treatment is not up-titrated and blood pressure (BP) control is not achieved. Several studies have shown that ambulatory BP (ABP) is superior to clinical measurements in predicting hypertension-induced target-organ damage and cardiovascular events in patients with RH.…”

Masked hypertension: a systematic review

“…In the last few years, a large number of editorials and reviews have addressed masked hypertension, summarizing some of the observations reported above and, above all, posing a number of questions [12,43,[51][52][53][54][55][56][57][58][59][60][61][62].…”

Current approach to masked hypertension: From diagnosis to clinical management

“…Patients with masked hypertension are generally older, more likely to be male and to have diabetes or a history of stroke or coronary heart disease. 24,[30][31][32][33][34] Other potential determinants of masked hypertension are physical activity and mental stress. In masked hypertension, the percentage of men has been reported to be higher than that of women, and ABPM was more closely associated with age than office BP.…”

“…In masked hypertension, the percentage of men has been reported to be higher than that of women, and ABPM was more closely associated with age than office BP. 24,[30][31][32][33][34] Obesity is another potential predictor of masked hypertension. The Ohasama study found that waist circumference, body mass index and waist-to-hip ratio were associated with masked hypertension and that these associations remained significant in a multivariate analysis.…”