Whitecoat hypertension and masked hypertension

High Blood Pressure Exercise Program

Foods to eat when you have High Blood Pressure

Get Instant Access

BP is a very labile hemodynamic parameter; it varies from heartbeat to heartbeat, from morning to evening, from winter to summer, from sleeping to awake, and from sitting to standing. The same holds true for any other cardiovascular hemodynamic parameter, such as heart rate, cardiac output, ejection fraction, or pulmonary wedge pressure. However, the information that is based on invasively obtained measurements is often considered more reliable than information based on simple BP recording. Numerous studies have documented that BP carefully measured by cuff, under standardized conditions in physicians' offices, is a powerful and reliable predictor of morbidity and mortality. More recent studies have documented that 24-hour ambulatory BP monitoring is an even closer surrogate end point for heart attack and stroke than is office-measured BP. As the correlation between 24-hour ambulatory BP measurement and office BP measurement is moderate at best, there will be, not unexpectedly, a significant number of people who are truly hypertensive but in whom the diagnosis is missed by office BP measurements (masked hypertension). Conversely, BP may be elevated in the office but not on ambulatory BP monitoring - an entity known to most clinicians as white-coat hypertension.

White-coat hypertension is a well-known clinical entity familiar to most physicians. A variety of studies, has shown that the risk ofpatients with white-coat hypertension is somewhat elevated but distinctly lower than in patients who have sustained hypertension. Despite being common, little is known about how to best manage white-coat hypertension. Out of fear of overtreatment, some physicians are taking a "wait and see" approach in patients. Conversely, out of fear of litigation, some physicians may take an overaggressive therapeutic approach, which can result in hypotension and orthostatic symptoms.

In contrast, masked hypertension is a much less well-known (but not necessarily a less common) entity, which seems to carry a distinctly more serious prognosis. The same entity has been described occasionally as reversed white-coat hypertension. It was initially regarded as being rare but was more recently found to be present, to some extent, in about one-third of the hypertensive population. Risk factors for masked hypertension are alcohol, tobacco, and caffeine, as well as physical inactivity. In the PAMELA (Pressioni Arteriose Monitorate E Loro Associazioni) population, patients with masked hypertension had a prevalence of echocardiographic LVH that was much greater than that of normotensive subjects. Inappropriate target organ disease (ie, inappropriate for office BP levels) should therefore trigger a suspicion ofmasked hypertension and motivate physicians to expose a susceptible patient to 24-hour ambulatory BP monitoring [83].

In the same PAMELA study, it was reported that more than 50% ofpatients with white-coat or masked hypertension developed sustained hypertension over a 10-year period, and, when compared with normotensives, white coat hypertensives had a 2.5-fold increased risk and masked hypertensives a 1.8-fold increase risk of developing sustained hypertension (Figure 30) [83]. This clearly shows that neither of the two conditions should be shrugged off as innocent observations. Both white-coat hypertension and masked hypertension need to be identified and diagnosed and deserve to be monitored carefully [84].

The clinician should remember that it's much easier to suspect a diagnosis of white-coat hypertension, as patients will usually say that their BP is normal at home. In contrast, masked hypertension needs to be looked out for, and there are only a few clinical hints as to its presence. A normal BP in the clinical setting does not mean that a patient is not at risk from an elevated BP, which can occur at other times of the day. This is particularly true in patients who are treated with antihypertensive drugs that do not cover a full 24-hour period. As the patient takes the medication in the morning, BP values in the physician's office are, most often, normal but may be substantially elevated at the end of the dosing interval (ie, during the night and early morning hours). Thus, in many hypertensive patients, clinic BP is seemingly well controlled, but early morning BP, before taking the medication, may be elevated, thereby accelerating the risk of cardiovascular events. For many clinicians, masked hypertension has unfortunately become a blind spot in antihypertensive therapy. Although a sweeping recommendation that all patients with high BP (or normal BP) should undergo 24-hour ambulatory BP monitoring cannot be made, the presence of inappropriate target organ disease, such as LVH

or microalbuminuria, should arise suspicion of masked hypertension and motivate physicians to initiate a further work-up. With regard to the therapeutic approach, we should remember that white-coat hypertension has a benign prognosis and can only be over-treated; therefore, a conservative approach is probably justified. In contrast, masked hypertension has a much more serious

Percentage of patients progressing to and regressing from true hypertension over 10 years

Labile Hypertension

Figure 30 Percentage of patients progressing and regressing to true hypertension over 10 years. A, Progression toward true hypertension. Numbers in the figure show the percentage of the patients who progressed toward true hypertension from masked hypertension, true normotension, and white-coat hypertension. NTN indicates normotension; HTN, hypertension. B, Regression from true hypertension. Numbers in the figure show the percentage of the patients who regressed from true hypertension to masked hypertension, true normotension, and white-coat hypertension. Reproduced with permission from Messerli and Makani [84].

Figure 30 Percentage of patients progressing and regressing to true hypertension over 10 years. A, Progression toward true hypertension. Numbers in the figure show the percentage of the patients who progressed toward true hypertension from masked hypertension, true normotension, and white-coat hypertension. NTN indicates normotension; HTN, hypertension. B, Regression from true hypertension. Numbers in the figure show the percentage of the patients who regressed from true hypertension to masked hypertension, true normotension, and white-coat hypertension. Reproduced with permission from Messerli and Makani [84].

prognosis and can only be under-treated; it deserves, therefore, a thorough evaluation and a more aggressive therapeutic approach.

Was this article helpful?

0 0
Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

Get My Free Ebook


Post a comment