Published online Jul 26, 2015. doi: 10.4330/wjc.v7.i7.373
Peer-review started: January 27, 2015
First decision: February 7, 2015
Revised: April 13, 2015
Accepted: May 7, 2015
Article in press: May 8, 2015
Published online: July 26, 2015
Processing time: 192 Days and 10.3 Hours
The advent of ambulatory blood pressure monitoring permitted examination of blood pressures during sleep and recognition of the associated circadian fall in pressure during this period. The fall in pressure, called the “dip”, is defined as the difference between daytime mean systolic pressure and nighttime mean systolic pressure expressed as a percentage of the day value. Ten percent to 20% is considered normal. Dips less than 10%, referred to as blunted or absent, have been considered as predicting an adverse cardiovascular event. This view and the broader concept that white coat hypertension itself is a forerunner of essential hypertension is disputable. This editorial questions whether mean arterial pressures over many hours accurately represent the systolic load, whether nighttime dipping varies from measure to measure or is a fixed phenomenon, whether the abrupt morning pressure rise is a risk factor or whether none of these issues are as important as the actual night time systolic blood pressure itself. The paper discusses the difference between medicated and nonmedicated white coat hypertensives in regard to the cardiovascular risk and suggests that further work is necessary to consider whether the quality and duration of sleep are important factors.
Core tip: While the blunted or absent nighttime pressure dip in nonmedicated white coat hypertensives is generally believed to be a predictor of adverse cardiovascular events, it does not appear to present the same risk in medicated white coat patients. Of the many measurable pressure issues, including pulse pressure and morning surge, during sleep and with awakening, only the mean systolic pressure appears to be the predictor of risk.