Blood pressure variability in relation to outcome in the International Database of Ambulatory blood pressure in relation to Cardiovascular Outcome

Abstract

Ambulatory blood pressure (BP) monitoring provides information not only on the BP level but also on the diurnal changes in BP.In the present review, we summarized the main findings of the International Database on Ambulatory BP in relation to Cardiovascular Outcome (IDACO) with regard to risk stratification based on BP variability. The predictive accuracy of daytime and nighttime BP and the night-to-day BP ratio depended on the disease outcome under study and treatment status, and differed for fatal outcomes compared with the composite of fatal and nonfatal diseases. An exaggerated morning surge, exceeding the 90th percentile of the population, is an independent risk factor for mortality and cardiovascular and cardiac events. Conversely, a sleep-trough or preawakening morning surge in systolic BP below 20 mm Hg is probably not associated with an increased risk of death or cardiovascular events. BP variability as captured by the average of the daytime and nighttime s.d. weighted for the duration of the daytime and nighttime interval (s.d. dn ) and the average real variability (ARV 24 ) predicted the outcome, but improved the prediction of the composite of all cardiovascular events by only 0.1%. In conclusion, the IDACO observations support the concept that BP variability adds to risk stratification, but above all highlight that 24-h ambulatory BP level remains the main predictor to be considered in clinical practice. Hypertension Research (2010) 33, 757-766; doi:10.1038/hr.2010.110; published online 8 July 2010Keywords: blood pressure; cardiovascular outcome; diurnal blood pressure variability; morning surge INTRODUCTION Ambulatory monitoring allows the registration of blood pressure (BP) throughout the day in patients engaged in their usual activities. Ambulatory BP recordings have high reproducibility, are not subject to digit preference, and avoid the transient rise of a patient's BP in response to a medical environment, the so-called white-coat effect. 1,2 Collaborative meta-analyses of individual patient data constitute a powerful research tool to clarify the role of cardiovascular risk factors in relation to total and cause-specific mortality and morbidity, over and beyond the prognostic information generated by single-cohort studies. 3,4 The international database on ambulatory BP monitoring 5 illustrated to what extent a meta-analysis of individual patient data can contribute to our understanding of the distribution 5,6 and the diurnal profile 5,7 of ambulatory BP across ethnically diverse populations. This database, constructed in 1993This database, constructed in -1994 however, lacked a

Blood pressure variability is significantly associated with ECG left ventricular mass in normotensive Africans: The SABPA Study

“…Schillaci et al 38 and Roman et al 43 also observed this lack of association in Caucasians with essential hypertension. Contradictory results have been provided over the years regarding the predictive value of BP variability, 4,8,10,14 which might be due to differences in methods, too few events or different indexes of BP variability. Interestingly, most of these studies focused on the general population or hypertensive groups, excluding the possibility that BP variability might be an effective measurement for the early identification of those at risk when focusing on normotensive groups exclusively.…”

“…50 Nonetheless, the weighted SD dn technique used in the present study was suggested as an accurate and useful measure. 4,10 Lastly, echocardiography was not used for determination of left ventricular mass, but we used a validated electrocardiographic method (Cornell product).…”

“…[1][2][3][4][5][6][7][8][9][10] Where some papers emphasize the importance of BP variability in prediction of risk of vascular events, 1,2,6,9 others question its prediction of cardiovascular outcome. 4,5,10 Despite this upsurge of recent papers, consistent evidence over the past three decades lends support that both target organ damage and the rate of cardiovascular events of hypertensive patients are significantly and independently related to the degree of BP variability. [11][12][13][14][15] A limitation of many of these papers is that either BP variability alone was investigated, or various measures of BP variability (such as s.d.…”

The risk of cold temperature: an important aspect of the determination of morning blood pressure surge

“…2 BP is a highly variable physiological trait, the fluctuation of which is a complex interaction between external environmental stimuli and the responses of individual cardiovascular systems. [3][4][5][6][7] From the view point of clinical management, BP variability consists of at least two types of phenomena: longterm fluctuations, such as day-night, day-today, weekly (for example, Monday BP surge) and seasonal changes, and short-term BP variations that occur within the daytime and nighttime periods (Figure 1). Several studies, but not all, have demonstrated that both short-term BP variability and long-term BP variability themselves are significantly associated with the target-organ damage and with future cardiovascular events independently of the 24-h BP levels.…”

“…Several studies, but not all, have demonstrated that both short-term BP variability and long-term BP variability themselves are significantly associated with the target-organ damage and with future cardiovascular events independently of the 24-h BP levels. [3][4][5][6][7] Intriguingly, certain reports have suggested that the peak of the incidence of cardiovascular diseases (CVDs) is likely to parallel the time with a greater extent of the BP variations. 1,8,9 For example, with respect to diurnal variation, most studies have shown an increased incidence of acute myocardial infarction, sudden cardiac death and stroke during the morning periods after waking up, and this variation appears to be closely associated with the diurnal variation of BP (that is, morning BP increase).…”