White coat hypertension and related phenomena. A clinical approach.

In this paper, several clinical problems associated with the diagnosis of hypertension are discussed. Blood pressure variability and reactivity are factors underlying the difficulties in the diagnosis of hypertension. These phenomena are interrelated and mixed. White coat hypertension (WCH), referring to the phenomenon of a high diastolic pressure at the doctor's office and a normal diurnal diastolic pressure when it is measured by ambulatory monitoring, is the most important clinical problem of diagnosis. Blood pressure variability is described, since it is essential to understand changes in pressure throughout the day, and its phasic and tonic components. Blood pressure differences between activity and rest, usually seen as daytime/night-time differences, allow for blood pressure control in most patients with moderate hypertension. Prevalence of WCH depends on the cut-off point used by the investigators for normal diurnal blood pressure; thus, between 53% and 12% of patients may have WCH. In our studies, a prevalence of 35% has been found. The alert reaction, labile and borderline hypertension and WCH result from a mix of both variability and reactivity, and patients with these conditions are at a higher cardiovascular risk than normotensive controls. Ambulatory blood pressure monitoring, which enables true hypertensives to be distinguished from false hypertensives, is the most useful technique available to date for the diagnosis of hypertension.