The clinical value of circadian variations of blood pressure.
Writing an editorial on the clinical relevance of the diurnal rhythm of blood pressure bears a two-sided risk. There is little doubt that 24 h ambulatory monitoring (ABPM) is the only practical way to investigate the diurnal rhythm of blood pressure and that acceptance of ABPM by physicians and regulatory authorities is largely dependent upon acceptance of the concept that knowledge of blood pressure values during day and night is clinically valuable information. However, underestimation of the many open methodological aspects regarding definition and reproducibility of daytime and night-time blood pressure and emphasis on positive reports showing an association between a blunted day-night blood pressure difference and cardiovascular damage would bear the risk of one being perceived as an uncritical reviewer of a hypothesis fitting with one's personal data [1-6]. At the opposite extreme, the exigency of neutrality could lead one to place excessive emphasis on the less positive or frankly negative evidence in this field (for a review, see [7]). In this issue of the Journal, several groups that are actively involved in clinical research projects with ABPM provide detailed and balanced contributions on several topics related to the diurnal changes in blood pressure.
Verdecchia
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Area Omogenea di Cardiologia e Medicina, Ospedale 'R. Silvestrini', Perugia, Italy.