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Nondipping blood pressure (BP) is associated with increased morbidity and mortality. This study examines the relationship of "dipping" in 24-hour ambulatory BP monitoring (ABPM) with awake and sleeping urinary norepinephrine (NE) and epinephrine (EPI), and that of urinary NE and EPI with urinary sodium (UNa). Fifty nondippers and 65 dippers were included in the present study. Collected data included age, sex, body mass index, history of hypertension, current antihypertensive treatment, ABPM data, and NE, EPI, and UNa values. Hierarchical multiple regression analysis with the night-to-day ratio (NDR) of systolic BP as a dependent variable showed that the composite term of the NDRs of urinary NE and EPI was a significant predictor for dipping. Results also show a differential role of NE and EPI in circadian UNa excretion in dippers and nondippers. These results indicate that the sympathetic nervous system is involved in the regulation of circadian BP variations and UNa excretion. [ABSTRACT FROM AUTHOR]

Although aortic-to-brachial pulse pressure amplification (PPamp) may offer prognostic information beyond brachial blood pressure (BP), this approach is limited in resource-limited settings. We aimed to derive an equation to impute central aortic PP (PPc) from simple clinical measures and assess whether imputed PPamp adds to the ability of brachial BP to predict mortality. METHODS An imputation equation for PPc, incorporating brachial PP, age, mean arterial pressure, and pulse rate, was identified from multivariate modeling of the factors associated with radial applanation tonometry-derived (measured) PPc in 1,179 community participants and validated in a clinical sample of 351 patients. We applied the equation to ambulatory awake BP and pulse rate values in a separate group of 4,796 patients referred for ambulatory monitoring and evaluated the impact on all-cause mortality. RESULTS Imputed PPc values closely approximated measured PPc (r2 = 0.96, mean difference ± (2 × SD) = 1.4 ± 6.2 mm Hg). In adjusted Cox proportional models including adjustments for awake brachial PP during 47,111 person-years of follow-up, where 648 patients died, hazards ratio for all-cause mortality per SD of awake PPamp was 0.79 (95% confidence interval (CI): 0.68-0.93, P < 0.005). The hazards ratio for brachial PP with (1.49, CI = 1.36-1.64, P < 0.0001) or without (1.46, CI = 1.35-1.59, P < 0.0001) PPamp in the model was similar. Awake PPamp also predicted survival independent of awake brachial systolic BP (P < 0.0001). CONCLUSIONS PPc imputed from simple clinical assessments closely approximates measured PPc. PPamp derived from imputed PPc adds to the ability of brachial BP to predict survival. In resource-limited settings, an imputation equation may be employed to approximate aortic BP and enhance risk prediction. [ABSTRACT FROM AUTHOR]

BackgroundAntihypertensive β-blocker use is associated with greater intervisit blood pressure variability (BPV) and with less favorable outcomes compared to other antihypertensive agents. A theoretical model demonstrated that accuracy and precision of BP measurement are affected by heart rate (HR) at a constant cuff deflation rate. We aimed to examine the empirical relationship between HR and BPV in a clinical setting.MethodsIntratracing variability in ambulatory BP monitoring (ABPM) were analyzed in search of a link between BPV and HR. BPV was expressed as standard deviation (s.d.), coefficient of variation (CV), and variability independent of the mean (VIM).ResultsIn a dataset of 4,693 subjects, HR was inversely associated with BPV and independently explained 1.3% of between-subject variation in s.d. of awake systolic BP (1.5% of CV and VIM). Linear regression suggested 0.5 mm Hg increase in s.d. of systolic BP per 10 beats per minute (bpm) decrease in HR. In a subset of 1,019 patients with available data on medications, HR was independently and inversely related with awake systolic BPV (P < 0.0001), more so in diuretic (P < 0.050) and renin-angiotensin system antagonists-treated (P < 0.050) patients. Associations of β-blockade with increased BPV were abolished by model-adjustment for HR. In another subset of patients who were monitored twice (n = 635), HR had a mild (0.6%) but significant (P < 0.05) inverse contribution to the change in awake systolic BPV between repeated monitoring.ConclusionsAmbulatory BPV is inversely related to HR and is not increased in referred patients treated with β-blockers after correction for HR.American Journal of Hypertension 2011; doi:10.1038/ajh.2011.230 [ABSTRACT FROM AUTHOR]

BackgroundMorning blood pressure surge (MS) is accepted to increase cardiovascular risk, but it is not clear how it should be defined. Because dipping on 24-h ambulatory blood pressure monitoring (ABPM) associates with improved outcome we hypothesized that MS will not predict mortality independent of dipping.MethodsWe investigated a cohort of 2,627 patients referred for ABPM with available values for at least 1-h after awakening, and related them to all-cause mortality.ResultsDuring 22,353 person-years of follow-up, 246 patients died. We used Cox proportional hazards models to explore mortality associated with different definitions of the MS. Only the '1-h' MS (difference between average blood pressure (BP) 1-h before and after awakening) was related to mortality: after multiple adjustments including 24-h systolic BP, those whose '1-h' MS was above median (>12 mm Hg) had mortality hazard ratio (HR) of 0.61, 95% CI: 0.47-0.79, P < 0.001. In predetermined subgroup analyses, nondippers (n = 1,039), had a highly significant MS-related decrease in mortality: HR 0.49, 95% CI: 0.34-0.73, P < 0.001, unlike dippers (n = 1,588), HR = 0.90, 95% CI: 0.60-1.34.ConclusionAmong nondipping subjects referred for ABPM, the MS is associated with decreased mortality.American Journal of Hypertension (2011). doi:10.1038/ajh.2011.58 [ABSTRACT FROM AUTHOR]

This article presents a study regarding the determinants and mortality associations of heart rate measured during ambulatory blood pressure monitoring. It also evaluates its informativeness during activity and sleep. Ambulatory heart rate in clinical practice adds prognostic information beyond that of other ambulatory blood pressure monitoring predictors. Heart rate measures during sleep, specifically the absence of dipping of heart rate to sleep levels, were associated with all-cause mortality.

Background: The prevalence and implications of masked hypertension are under investigation. The aim of this study was to investigate the clinical characteristics associated with masked hypertension in subjects referred for ambulatory blood pressure (BP) monitoring. Methods: We analyzed 1494 BP monitoring sessions. A subject was considered to have isolated clinic hypertension if clinic BP was ≥140/90 mm Hg and awake BP was <135/85 mm Hg. Masked hypertension was diagnosed when clinic BP was <140/90 mm Hg and awake BP was ≥135/85 mm Hg. Results: Of 1494 individuals, 16% had normal BP, 11% had isolated clinic hypertension, 61% had hypertension, and 11% had masked hypertension. Subjects with masked hypertension were younger and more likely to be male than subjects with isolated clinic hypertension, and their awake heart rate was significantly higher. A negative correlation was found between the awake-clinic systolic BP difference and clinic systolic BP (r = −0.7, P < .0001). The reproducibility of the masking phenomenon was comparable to that of other variables. Conclusions: In a group of consecutive subjects referred for ambulatory BP monitoring, masked hypertension was found to be as common as isolated clinic hypertension. Masking was correlated with male sex, young age, and higher awake heart rate, thus suggesting a causal relationship with greater daytime physical activity. The linear association of the masking and the white-coat effects to clinic BP suggests that regression toward the mean may partially explain these phenomena. [Copyright &y& Elsevier]

Background: Pulse pressure is a derivative of arterial stiffness. We have previously demonstrated ambulatory pulse pressure to be relatively independent from the blood pressure (BP) lowering during sleep, and thus of a neurogenic effect. On the other hand, white coat BP effects are thought to involve neurogenic activation. The aim of this work was to analyze white coat induced variability in pulse pressure.Methods: Percent clinic–awake differences in systolic BP (SBP) and pulse pressure (white coat effects) were calculated for 688 consecutive subjects (mean age 60 ± 16 years, 58% female). Of the subjects, 23% had controlled hypertension, 45% uncontrolled hypertension, 8% normotension, and 4% isolated office hypertension; all were referred to our unit for 24-h ambulatory BP monitoring.Results: Pulse pressure highly correlated with SBP (r = 0.82, P < .00001). We found a larger white coat effect on pulse pressure than on SBP (8.3% and 5.2%, respectively, P ≤ .0001). This was true in all subgroups except in normotensive subjects. Specifically, the magnitude of the white coat effect on pulse pressure was greater than on SBP in subjects with treated hypertension, untreated hypertension, and isolated office hypertension, and in young hypertensive subjects, older subjects, and those with diabetes.Conclusions: Although pulse pressure is related to the mechanical properties of large arteries, it is also influenced by the white coat effect, a neurogenic process. Furthermore, in hypertensive but not in normotensive subjects, the white coat effect on pulse pressure is significantly more pronounced than on SBP. [Copyright &y& Elsevier]

Abstract: Purpose: Referral to ambulatory blood pressure monitoring may have bearing upon blood pressure control and prognosis. We describe sex-related differences in referral for ambulatory monitoring and their prognostic impact. Methods: Between 1991 and 2005, 3957 patients were monitored in our ambulatory monitoring service, of whom 2114 (53%) were women. Demographic and clinical data were analyzed according to sex. Results: Age (58±15 vs 52±17 years, respectively) and body mass index (27.5±4.9 vs 26.9±4.0 kg/m2, respectively) were higher in women than men. Treatment for hypertension was more prevalent in women (62% vs 53%, respectively). Clinic systolic blood pressure (148±24 vs 146±20 mm Hg, respectively) and clinic pulse pressure (65±22 vs 59±18 mm Hg, respectively) were higher in women compared with men. In women, the white-coat effect was increased, compared with men; 5.2±12.4% vs 1.5±10.7% systolic, and 5.4±11.2% vs 3.6±10.3% diastolic. Consequently, women had lower ambulatory blood pressure than men. In women, 24-hour blood pressure was 136±17/76±10 vs 140±15/81±10 mm Hg in men, awake blood pressure 141±17/80±11 vs 144±15/84±10 mm Hg, and sleep blood pressure was 125±19/67±10 vs 127±18/71±11 mm Hg. Age-adjusted ambulatory blood pressure also was lower in women. Ambulatory heart rate was higher in women (P <.0001). Kaplan-Meier survival did not differ by sex (P =.66), despite older age and higher clinic blood pressure. Conclusions: The results might imply that referral was driven by the physicians'' overall patient risk perception. The greater magnitude of white-coat effect in women, and correspondingly lower ambulatory blood pressure, might in part account for similar mortality in the face of older age and higher clinic blood pressure. [Copyright &y& Elsevier]

Abstract: Background: White-coat hypertension and masked hypertension have clinical and prognostic consequences. However, reproducibility of these phenomena is unknown. We examined the reproducibility of the white-coat and masking effects with real-life ambulatory blood pressure monitoring (ABPM). Methods: In a retrospective analysis of a prospectively assembled ABPM database there were 196 subjects (age 58±16 years, 59% female, 73% treated for hypertension) who underwent repeat ABPM for standard clinical indications. White-coat hypertension (or isolated manual uncontrolled hypertension) was defined as normal (<135/85 mmHg) awake blood pressure (BP) and abnormal (≥140/90 mmHg) manual BP. Masked hypertension (or isolated ambulatory uncontrolled hypertension) was defined as abnormal awake BP with normal manual BP. Results: Treated and untreated subjects had similar distribution among hypertension subgroups; 16% white-coat hypertension (in treated subjects, isolated manual uncontrolled hypertension), 13% masked hypertension (in treated subjects, isolated ambulatory uncontrolled hypertension), 59% uncontrolled hypertension, 12% normal blood pressure (or controlled hypertension). In the second session the prevalence of white-coat and masked hypertension increased. Of 31 subjects with white-coat hypertension in the first session 19 (61%) remained ambulatory normotensive in the second session, while 18 of 25 (72%) masked hypertensive subjects remained ambulatory hypertensive. The reproducibility of the systolic manual–awake blood pressure difference was not inferior to that of other ambulatory variables. In untreated subjects the reproducibility of white-coat hypertension, masked hypertension and the white-coat effect was even better. Conclusion: In a real-life ABPM database, we found white-coat hypertension and the masking phenomenon to be reasonably reproducible, as compared to other BP variables. [Copyright &y& Elsevier]

Abstract: Purpose: The American Heart Association Council on High Blood Pressure Research recently issued recommendations for blood pressure measurement in humans. According to these recommendations, normal 24-hour ambulatory blood pressure is defined as less than 130/80 mm Hg. Concurrently, normal daytime and nighttime blood pressure levels are defined as less than 135/85 mm Hg and less than 120/70 mm Hg, respectively. Our aim was to investigate the intrinsic compatibility of these blood pressure cutoffs in clinical practice. Subjects and methods: We analyzed 4121 consecutive ambulatory blood pressure measurement sessions. Age was 57 ± 7 years, 53% were female, and 64% and 9% were treated for hypertension and diabetes, respectively. Body mass index was 27 ± 4 kg/m2, and manual blood pressure was 148 ± 22/85 ± 12 mm Hg. Subjects were classified as having normal 24-hour blood pressure if the corresponding value was less than 130/80 mm Hg. Normal awake-sleep blood pressure was diagnosed if awake blood pressure was less than 135/85 mm Hg and sleep blood pressure was less than 120/70 mm Hg. Results: Concordance between the cutoffs was found in 92% of the subjects (kappa = 0.77). Among the 8% of discordant subjects, only 1% were hypertensive applying the 24-hour (but not awake-sleep) blood pressure values, whereas 7% were hypertensive according to awake-sleep but not 24-hour blood pressure values (P <.0001). Conclusions: In real-life ambulatory blood pressure measurement, a generally good agreement was found between the recently issued ambulatory blood pressure normality suggestions. However, some subjects are classified as hypertensive only according to one of these methods, more often by the awake-sleep cutoff of 135/85 and 120/70 mm Hg. This discordance may be significant in large-scale clinical blood pressure monitoring. [Copyright &y& Elsevier]