Rothwell PM, Howard SC, Dolan E, O'Brien E, Dobson JE, Dahlöf B et al. Prognostic significance of visit-to-visit variability, maximum systolic blood pressure, and episodic hypertension. The Lancet 2010; 375: 895-905

Stroke Prevention Research Unit, University Department of Clinical Neurology, John Radcliffe Hospital, Headington, Oxford, UK.
The Lancet (Impact Factor: 45.22). 03/2010; 375(9718):895-905. DOI: 10.1016/S0140-6736(10)60308-X
Source: PubMed


The mechanisms by which hypertension causes vascular events are unclear. Guidelines for diagnosis and treatment focus only on underlying mean blood pressure. We aimed to reliably establish the prognostic significance of visit-to-visit variability in blood pressure, maximum blood pressure reached, untreated episodic hypertension, and residual variability in treated patients.
We determined the risk of stroke in relation to visit-to-visit variability in blood pressure (expressed as standard deviation [SD] and parameters independent of mean blood pressure) and maximum blood pressure in patients with previous transient ischaemic attack (TIA; UK-TIA trial and three validation cohorts) and in patients with treated hypertension (Anglo-Scandinavian Cardiac Outcomes Trial Blood Pressure Lowering Arm [ASCOT-BPLA]). In ASCOT-BPLA, 24-h ambulatory blood-pressure monitoring (ABPM) was also studied.
In each TIA cohort, visit-to-visit variability in systolic blood pressure (SBP) was a strong predictor of subsequent stroke (eg, top-decile hazard ratio [HR] for SD SBP over seven visits in UK-TIA trial: 6.22, 95% CI 4.16-9.29, p<0.0001), independent of mean SBP, but dependent on precision of measurement (top-decile HR over ten visits: 12.08, 7.40-19.72, p<0.0001). Maximum SBP reached was also a strong predictor of stroke (HR for top-decile over seven visits: 15.01, 6.56-34.38, p<0.0001, after adjustment for mean SBP). In ASCOT-BPLA, residual visit-to-visit variability in SBP on treatment was also a strong predictor of stroke and coronary events (eg, top-decile HR for stroke: 3.25, 2.32-4.54, p<0.0001), independent of mean SBP in clinic or on ABPM. Variability on ABPM was a weaker predictor, but all measures of variability were most predictive in younger patients and at lower (<median) values of mean SBP in every cohort.
Visit-to-visit variability in SBP and maximum SBP are strong predictors of stroke, independent of mean SBP. Increased residual variability in SBP in patients with treated hypertension is associated with a high risk of vascular events.

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Available from: Eamon Dolan, Nov 13, 2014
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    • "While nighttime BP has been found to be a stronger predictor of cardiovascular risk than clinic or daytime ABP (Hansen et al., 2011), increasing evidence has pointed to the importance of also considering morning surges in ABP in addition to nighttime BP (Kario et al., 2003; Verdecchia et al., 2012). The importance of studying the dynamics of ABP is further reflected in the inclusion of trend reports in popular ABP measurement tools such as the dabl system (O'Brien, 2011), which provide indices such as time-weighted measures of variability, measures of nocturnal dip, morning surge, peak as well as trough levels, and smoothness of BP curves, among many other indices of CV events (Dolan et al., 2006; Rothwell et al., 2010). Despite the richness of the dynamic information in ABP data, diagnosis/prognosis involving ABP is typically performed on levels of ABP obtained from isolated segments of the data. "
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