Awake Systolic Blood Pressure Research Articles

Administration-Time Differences in Effects of Hypertension Medications on Ambulatory Blood Pressure Regulation

Specific features of the 24-h blood pressure (BP) pattern are linked to progressive injury of target tissues and risk of cardiovascular disease (CVD) events. Several studies have consistently shown an association between blunted asleep BP decline and risk of fatal and nonfatal CVD events. Thus, there is growing focus on ways to properly control BP during nighttime sleep as well as during daytime activity. One strategy, termed chronotherapy, entails the timing of hypertension medications to endogenous circadian rhythm determinants of the 24-h BP pattern. Significant and clinically meaningful treatment-time differences in the beneficial and/or adverse effects of at least six different classes of hypertension medications, and their combinations, are now known. Generally, calcium channel blockers (CCBs) are more effective with bedtime than morning dosing, and for dihydropyridine derivatives bedtime dosing significantly reduces risk of peripheral edema. The renin-angiotensin-aldosterone system is highly circadian rhythmic and activates during nighttime sleep. Accordingly, evening/bedtime ingestion of the angiotensin-converting enzyme inhibitors (ACEIs) benazepril, captopril, enalapril, lisinopril, perindopril, quinapril, ramipril, spirapril, trandolapril, and zofenopril exerts more marked effect on the asleep than awake systolic (SBP) and diastolic (DBP) BP means. Likewise, the bedtime, in comparison with morning, ingestion schedule of the angiotensin-II receptor blockers (ARBs irbesartan, olmesartan, telmisartan, and valsartan exerts greater therapeutic effect on asleep BP, plus significant increase in the sleep-time relative BP decline, with the additional benefit, independent of drug terminal half-life, of converting the 24-h BP profile into a more normal dipping pattern. This is the case also for the bedtime versus upon-awakening regimen of combination ARB-CCB, ACEI-CCB, and ARB-diuretic medications. The chronotherapy of conventional hypertension medications constitutes a new and cost-effective strategy for enhancing the control of daytime and nighttime SBP and DBP levels, normalizing the dipping status of their 24-h patterning, and potentially reducing the risk of CVD events and end-organ injury, for example, of the blood vessels and tissues of the heart, brain, kidney, and retina. (Author correspondence: rhermida@uvigo.es)

Association of Heart Rate With Blood Pressure Variability: Implications for Blood Pressure Measurement

Antihypertensive 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. Intratracing 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). In 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. Ambulatory BPV is inversely related to HR and is not increased in referred patients treated with β-blockers after correction for HR.

Abstract 17769: Increased Blood Pressure Variability During Early Bereavement

Background: Bereavement is a unique stress with heightened cardiovascular disease (CVD) risk for the surviving spouse; the physiological changes underlying this increased risk have not been well defined. Aims: Since increased blood pressure variability (BPV) has been associated with higher CVD mortality, we tested the hypothesis that there is greater BPV during bereavement. Methods: Sixty-three bereaved (B) spouses and parents (41F/22M; aged 65 ± 2 yrs) were studied within 2 weeks of bereavement (acute) and at 6 months (6m), and compared to a non-bereaved (NB) reference group of 78 spouses of discharged patients (52F/26M; age 64 ± 1 yrs) underwent 24-hour ambulatory blood pressure (ABP) assessment using the validated TM-2430 device. Systolic BPV for the awake period (0800 - 2000 hours) was calculated as standard deviation (SD), coefficient of variability (CoV) and average real variability (ARV). SD identifies the spread of BP measurements around a single value (the mean) not accounting for order of measurement, whereas ARV averages absolute differences of consecutive measurements. Results: Acutely bereaved have significantly higher awake systolic blood pressure (SBP, 136 ± 2 vs 131 ± 1 mmHg, p&lt;0.05) and systolic BPV measures (SD and ARV) compared with non-bereaved (see Table 1). By 6 months, there were no longer significant differences between B and NB in ARV or SBP. However, BPV measured by SD remained higher in bereaved at 6 months. Conclusion: This study, the first to focus on CVD risk in early bereavement, demonstrates increased blood pressure variability that may contribute to the increased CVD events. Table 1

Response to Comment on: Hermida et al. Influence of Time of Day of Blood Pressure–Lowering Treatment on Cardiovascular Risk in Hypertensive Patients With Type 2 Diabetes. Diabetes Care 2011;34:1270–1276

We thank Rossen and Hansen (1) for their interest in our article (2). The participants represented a consecutive series of patients fulfilling the exclusion/inclusion criteria who were recruited from those referred to the hospital for evaluation by ambulatory blood pressure monitoring (ABPM) mainly to confirm or reject the diagnosis of hypertension inferred by clinic cuff blood pressure measurement. Diagnosis of hypertension in our trial was based on accepted ABPM criteria, i.e., an awake systolic blood pressure (SBP)/diastolic blood pressure (DBP) mean ≥135/85 mmHg and/or an asleep SBP/DBP mean ≥120/70 mmHg (3). Despite a recommended target goal for clinic SBP/DBP in diabetes of 130/80 mmHg, current guidelines do not provide separate ABPM threshold values for patients with and without diabetes (3). Patients with diabetes in our trial …

Socioeconomic position is positively associated with blood pressure dipping among African-American adults: the Jackson Heart Study.

Blunted nocturnal blood pressure (NBP) dipping is a significant predictor of cardiovascular events. Lower socioeconomic position (SEP) may be an important predictor of NBP dipping, especially in African Americans (AA). However, the determinants of NBP dipping are not fully understood. The cross-sectional associations of individual and neighborhood SEP with NBP dipping, assessed by 24-h ambulatory BP monitoring, were examined among 837 AA adults (Mean age: 59.2 ± 10.7 years; 69.2% women), after adjustment for age, sex, hypertension status, body mass index (BMI), health behaviors, office, and 24-h systolic BP (SBP). The mean hourly SBP was consistently lower among participants in the highest category of individual income compared to those in the lowest category, and these differences were most pronounced during sleeping hours. The odds of NBP dipping (defined as >10% decline in the mean asleep SBP compared to the mean awake SBP) increased by 31% (95% confidence interval: 13-53%) and 18% (95% confidence interval: 0-39%) for each s.d. increase in income and years of education, respectively, after multivariable adjustment. NBP dipping is patterned by income and education in AA adults even after accounting for known risk factors. These results suggest that low SEP is a risk factor for insufficient NBP dipping in AA.

The Effect of Different Volumes of Acute Resistance Exercise on Elderly Individuals with Treated Hypertension

Acute resistance exercise can reduce the blood pressure (BP) of hypertensive subjects. The aim of this study was to evaluate the effect of different volumes of acute low-intensity resistance exercise over the magnitude and the extent of BP changes in treated hypertensive elderly individuals. Sixteen participants (7 men, 9 women), with mean age of 68 ± 5 years, performed 3 independent randomized sessions: Control (C: 40 minutes of rest), Exercise 1 (E1: 20 minutes, 1 lap in the circuit), and Exercise 2 (E2: 40 minutes, 2 laps in the circuit) with the intensity of 40% of 1 repetition maximum. Blood pressure was measured before (during 20 minutes) and after each session (every 5 minutes during 60 minutes) using both a mercury sphygmomanometer and a semiautomatic device (Omrom-HEM-431). After that, 24-hour ambulatory blood pressure monitoring was performed (Dyna-MAPA). Blood pressure decreased during the first 60 minutes (systolic: p < 0.01, diastolic: p < 0.05) after all exercise sessions. Only the highest volume session promoted a reduction of mean systolic 24-hour BP and awake BP (p < 0.05) after exercise, with higher diastolic BP during sleep (p < 0.05). Diastolic 24-hour BP and both systolic and diastolic BP during sleep were higher after E1 (p < 0.05). Concluding, acute resistive exercise sessions in a circuit with different volumes reduced BP during the first 60 minutes after exercise in elderly individuals with treated hypertension. However, only the highest volume promoted a reduction of mean 24-hour and awake systolic BP.

Automated Office Blood Pressure and 24-h Ambulatory Measurements are Equally Associated With Left Ventricular Mass Index

To determine whether automated office blood pressure (AOBP) readings are associated with left ventricular mass (LVM) index as closely as those of 24-h ambulatory blood pressure (ABP) and also to confirm that the values of the two methods are comparable in the appraisal of blood pressure in a European population referred for suspected hypertension. In a sample of 90 individuals with office hypertension, we compared AOBP to awake systolic ABP measurements (ABPM) values and their associations with LVM indices, expressed as LVM divided by body surface area (LVMI(BSA)) and by height(2.7) (LVMI(H)). Mean awake systolic ABP was 136 ± 16 mm Hg and mean systolic AOBP was 140 ± 15 mm Hg (P < 0.002). Mean awake diastolic ABP was 87 ± 11 mm Hg and mean diastolic AOBP was 88 ± 12 mm Hg (P = 0.08). AOBP readings were as closely associated with LVMI(BSA) (r = 0.37) as were those of awake systolic blood pressure (SBP) (r = 0.37). The correlation between LVMI(H) and both mean awake systolic ABP and mean systolic AOBP was r = 0.37 (P < 0.001) and r = 0.34 (P = 0.001), respectively. High-quality AOBP readings and ABP measurements correlate equally well with LVM indices, further supporting the use of AOBP in the clinical setting. Moreover, readings from both techniques are comparable in the assessment of blood pressure.

Effect of hospitalization on 24-h ambulatory blood pressure of hypertensive patients

The aim of this study is to assess the effect of hospital admission on 24-h ambulatory blood pressure (ABP) in hypertensive subjects. Treated or untreated hypertensive adults with open-angle glaucoma underwent inpatient and outpatient 24-h ABP monitoring in a random order 4 weeks apart. Awake ambulatory hours, awake in-bed hours and sleep hours were reported by participants. The nighttime-to-daytime ABP dip (%) and the sleeping-to-awake dip (ambulatory and in-bed) were determined using the two ABP recordings. A total of 40 subjects were analyzed (mean age 65.7 ± 8.4 (s.d.) years, n=19 men). Daytime systolic BP (SBP) was lower in the hospital than in the outpatient setting (mean difference 4.3 ± 10.4 mm Hg, P=0.01), as was the awake ambulatory SBP (mean difference 5.0 ± 11.1 mm Hg, P=0.008). No differences were detected in 24 h, nighttime or sleeping SBP or in any of the respective diastolic outpatient vs. inpatient ABP measurements. The nighttime SBP dip (vs. daytime) was larger in the outpatient setting (8.9 ± 7.5% and 5.2 ± 4.7%, respectively; P=0.003). Sleeping SBP dip (vs. awake ambulatory and awake in-bed) was also larger in the outpatient setting (11.1 ± 7.3 and 7.8 ± 5.9%, respectively; P=0.02) with no difference in diastolic ABP. These data suggest that inpatient 24-h ABP monitoring does not reflect the usual BP level during routine daily life, nor does it represent the usual diurnal pattern of an individual. Relying on the 24-h ABP monitoring performed in the hospital environment may lead to an underestimation of ABP and an overdiagnosis of non-dippers. Therefore, 24-h ABP monitoring for decision making regarding diagnosis and treatment of hypertension should be performed only in the routine daily conditions of each individual.

A primary care pragmatic cluster randomized trial of the use of home blood pressure monitoring on blood pressure levels in hypertensive patients with above target blood pressure

The measurement of blood pressure (BP) at home by patients with hypertension is increasingly used to assess and monitor BP. Evidence for its effectiveness in improving BP control is mixed. To determine if home BP monitoring improves BP a pragmatic cluster randomized contolled trial was carried out in family practices in southeastern Ontario, Canada. Family practice patients with uncontrolled hypertension were recruited to the trail. Patients were divided into two groups: one with at least weekly measurements of BP at home, recording those measurements and showing those to the family physician during office visits for hypertension and the control group were given usual care. The primary outcome was mean awake BP on ambulatory monitoring at 6- and 12-month follow-up and the secondary outcomes were mean BP on full 24-hour ambulatory blood pressure monitoring (ABPM), mean sleep BP on ABPM and BP on the BpTRU device, all at 6- and 12-month follow-up. Home BP monitoring did not improve BP compared to usual care at 12-month follow-up: mean awake systolic BP on ABPM [141.1 versus 142.8 mmHg, mean difference 1.7 mmHg; 95% confidence interval (CI) -0.6 to 4.0, P = 0.314] and mean awake diastolic BP on ABPM (78.7 versus 79.4 mmHg, mean difference 0.7 mmHg; 95% CI -7.7 to 9.1, P = 0.398). Similar negative results were obtained for men and women separately. However, outcomes using the full 24-hour ABPM and the BpTRU device showed a significantly lower diastolic BP at 12 months. When analysis was done by sex, this effect was shown to be only in men. Home BP monitoring may improve BP control in men with hypertension.

Association of Arterial Hypertension With Renal Target Organ Damage in Kidney Transplant Recipients: The Predictive Role of Ambulatory Blood Pressure Monitoring

Although arterial hypertension is a powerful predictor of graft failure, only few studies have evaluated 24-hr blood pressure (BP) profile in renal transplant recipients (RTRs). We performed ambulatory blood pressure monitoring (ABPM) in 94 RTRs (65 men; age 28-71 years) with 1-year functioning grafts. Serum biochemical parameters, daily proteinuria, and transplantation-related data were evaluated in all subjects. ABPM showed that only 5% of RTRs were normotensives (BP<130/80 mm Hg) and identified 29% of patients with nocturnal hypertension. A strong, direct correlation was shown between each set of both systolic BP and diastolic BP measured by ABPM and serum creatinine, daily proteinuria, and serum triglycerides (P at least <0.025 for each). Serum creatinine immediately after transplantation and 1-yr asleep diastolic BP were the only significant predictors of 1-yr creatinine (P<0.0001; r=0.49), whereas awake systolic BP was the only predictor of daily proteinuria (r=0.39; P=0.005) by multiple regression analysis. BP assessed by ABPM proved to be a stronger predictor of renal graft damage than traditional immunologic factors. ABPM improved the diagnostic accuracy of arterial hypertension in RTRs and was the only effective tool in disclosing the association of BP with 1-year renal transplant outcome.

Comparison of the Anti-Hypertensive Effects of the L/N-Type Calcium Channel Antagonist Cilnidipine, and the L-Type Calcium Channel Antagonist Amlodipine in Hypertensive Patients with Cerebrovascular Disease

It is known that the risk of cerebral stroke recurrence in post-stroke patients is comparatively higher than in normal subjects, and it is suggested that autonomic nervous system dysfunctions elevate this risk. We investigated the anti-hypertensive effects of cilnidipine, a Ca antagonist which suppresses sympathetic nerve activation, in hypertensives with chronic-stage cerebrovascular disease in a comparison with amlodipine. Amlodipine 5-7.5 mg/day, or cilnidipine 5-10 mg/day was administered to 78 hypertensive subjects (greater than 140 mmHg systolic, or 90 mmHg diastolic) undergoing outpatient treatment. Amlodipine or cilnidipine was also administered similarly, to 30 subjects having hypertension associated with a cerebral infarct which occurred more than one month earlier due to cerebral thrombosis or embolism. After 3 months administration, the subjects' blood pressures and pulse rates were recorded with an ambulatory blood pressure monitor over 24 hours. No difference was recognized in patient age, gender, and systolic and diastolic blood pressure before treatment between the groups. In the cilnidipine groups, no difference in average 24-hour or waking systolic blood pressure values was seen between cerebrovascular disease (CVD) subjects and non-CVD subjects, although in the amlodipine groups, CVD subjects had significantly higher blood pressure values than non-CVD subjects. In the cilnidipine group, the coefficient of variation values of pulse rate were significantly higher in CVD subjects than in non-CVD subjects (p<0.05). In patients with recent stroke, a Ca antagonist with no sympathetic nerve suppression had weaker blood pressure-lowering effects. Significantly increased pulse rate variability, shown in the CVD subjects administered cilnidipine, suggests that cilnidipine enhanced the parasympathetic function in hypertensive patients with CVD.

Clinical variables associated with non-dipping of nocturnal blood pressure in type 2 diabetes

Aim Non-dipping of nocturnal BP (blood pressure) is common in people with type 2 diabetes and is associated with increased risk of cardiovascular morbidity and mortality. This study aimed to identify the factors associated with nocturnal non-dipping of BP in people with type 2 diabetes. Methods Data were examined from 100 people with type 2 diabetes who had undergone ambulatory BP monitoring. Dippers were defined as those with a systolic night-time BP dip over 15%, and non-dippers as those with a systolic night-time BP dip of under 5%. Results There was no significant difference between the mean awake systolic BP in the dipping (142.9 mmHg) and the non-dipping (142.0 mmHg) groups (p=0.77). Non-dippers were significantly older (p&lt;0.0001) with a higher prevalence of albuminuria (p=0.003) and of macrovascular disease (p=0.008) when compared with the dipping group. After adjustment for age, albuminuria remained more prevalent within the non-dipping group (p=0.007). There was no significant difference in glycaemic control, type of diabetes treatment, smoking status, or gender between the groups. Conclusion Albuminuria is strongly associated with non-dipping of nocturnal BP in people with type 2 diabetes.

Ambulatory blood pressure as an independent determinant of brain atrophy and cognitive function in elderly hypertension

Recent studies have demonstrated a relationship between brain atrophy and hypertension. Systolic hypertension in the elderly has been found to be a risk factor for cognitive impairment. We studied the relationship of ambulatory blood pressure with brain atrophy and cognitive function. We performed ambulatory blood pressure monitoring and brain magnetic resonance imaging in 55 unmedicated elderly hypertensive patients (72.7 +/- 6.0 years old). The volume of total brain matter was measured using an intensity contour-mapping algorithm. Cognitive function was assessed by mini-mental state examination score. Total brain matter volume and cognitive function were significantly correlated (r = 0.314, P = 0.02). Total brain matter volume was significantly negatively correlated with age (r = -0.365, P = 0.006), 24-h systolic blood pressure (r = -0.343, P = 0.01), awake systolic blood pressure (r = -0.278, P = 0.04) and sleep systolic blood pressure (r = -0.491, P = 0.0001), and significantly positively correlated with male sex (r = 0.493, P = 0.0001), body mass index (r = 0.282, P = 0.04) and nocturnal systolic blood pressure dipping (r = 0.323, P = 0.02). Mini-mental state examination score was significantly negatively correlated with age (r = -0.277, P = 0.04) and sleep systolic blood pressure (r = -0.360, P = 0.007), and significantly positively correlated with nocturnal systolic blood pressure dipping (r = 0.402, P = 0.002). In multiple linear regression analysis adjusted for age, sex, and body mass index, sleep systolic blood pressure (P = 0.009) was more significantly negatively associated with total brain matter volume than was either 24-h (P = 0.035) or awake (P = 0.020) systolic blood pressure. In elderly hypertensive patients, absolute ambulatory systolic blood pressure level (particularly during sleep) and nocturnal dipping in systolic blood pressure were strong indicators of brain matter volume and cognitive function.

Ambulatory Blood Pressure Is a Better Marker Than Clinic Blood Pressure in Predicting Cardiovascular Events in Patients With/Without Type 2 Diabetes

The prognostic significance of ambulatory blood pressure (ABP) has not been established in patients with type 2 diabetes (T2DM). In order to clarify the impact of ABP on cardiovascular prognosis in patients with or without T2DM, we performed ABP monitoring (ABPM) in 1,268 subjects recruited from nine sites in Japan, who were being evaluated for hypertension. The mean age of the patients was 70.4 +/- 9.9 years, and 301 of them had diabetes. The patients were followed up for 50 +/- 23 months. We investigated the relation between incidence of cardiovascular diseases (CVDs) and different measures of ABP, including three categories of awake systolic blood pressure (SBP <135, 135-150, and >150 mm Hg), sleep SBP (<120, 120-135, and >135 mm Hg), and dipping trends in nocturnal blood pressure (BP) (dippers, nondippers, and risers). Cox regression models were used in order to control for classic risk factors. Higher awake and sleep SBPs predicted higher incidence of CVD in patients with and without diabetes. In multivariable analyses, elevated SBPs while awake and asleep predicted increased risk of CVD more accurately than clinic BP did, in both groups of patients. The relationships between ABP level and CVD were similar in both groups. In Kaplan-Meier analyses, the incidence of CVD in nondippers was similar to that in dippers, but risers experienced the highest risk of CVD in both groups (P < 0.01). The riser pattern was associated with a approximately 150% increase in risk of CVD, in both groups. These findings suggest that ABPM is a better predictor of cardiovascular risk than clinic BP, and that this holds true for patients with or without T2DM.

Added Impact of Obesity and Insulin Resistance in Nocturnal Blood Pressure Elevation in Children and Adolescents

The aim of the present study was to analyze the relationship between insulin resistance and the ambulatory blood pressure components in obese children and adolescents. Eighty-seven overweight and obese white children and adolescents of both sexes, of European origin from 6 to 18 years of age (mean age: 10.9+/-2.7 years), were selected. Obesity was defined on the basis of a threshold body mass index z score >2 (Cole's least mean square method) and overweight with a body mass index from the 85th to 97th percentile. A validated oscillometric method was used to measure ambulatory BP (Spacelabs 90207) during 24 hours. Fasting glucose and insulin were measured, and the homeostasis model assessment index was calculated. Subjects were grouped into tertiles of homeostasis model assessment index. No significant differences in terms of age, sex, and body mass index z score distribution were observed among groups. When adjusted by age, sex, and height, nocturnal systolic blood pressure and heart rate were significantly higher in subjects in the highest homeostasis model assessment index tertile (>4.7) as compared with those of the other groups, whereas no differences were observed for awake systolic blood pressure or heart rate. Whereas body mass index z score was more closely related with blood pressure and heart rate values, waist circumference was strongly related with insulin resistance. Moreover, both waist circumference and insulin resistance were mainly associated with higher nocturnal but not with awake blood pressure. The early increment of nocturnal blood pressure and heart rate associated with hyperinsulinemia may be a harbinger of hypertension-related insulin resistance and may contribute to heightened cardiovascular risk associated with this condition.

Prediction of strokes versus cardiac events by ambulatory monitoring of blood pressure: results from an international database

We performed this study to elucidate the role of nighttime versus daytime ambulatory blood pressure in predicting stroke and cardiac events. The International Collaborative Study of the Prognostic Utility of ABPM, which includes prospective cohort studies of ambulatory blood pressure monitoring (ABPM) from seven sites, was analyzed in this study. The incidence of stroke and cardiac events were evaluated for an average of 5.8 years. A cox proportional hazards model of adjusting for site, age, sex, BMI, total cholesterol, smoking, and history of antihypertensive medications was used for the analysis. Dipping was defined as the percentage decline in nighttime systolic blood pressure (SBP) relative to daytime SBP. Three hundred and eleven cardiac events and 318 strokes were seen during the follow up periods. Awake and sleep SBP were both significantly associated with both cardiac and stroke events. When the awake and sleep SBP were entered together in the model, awake SBP was more strongly associated with cardiac events than sleep SBP (chi2=12.4, d.f.=1, P=0.0004); conversely, sleep SBP (chi2=13.5, d.f.=1, P<0.0002) was more predictive for stroke events than awake SBP, although awake SBP also remained a significant predictor (chi2=7.03, d.f.=1, P=0.008). The amount of dipping was a significant inverse predictor of stroke [hazards ratio (HR) 0.81 per 10% increase in dipping, confidence interval (CI) 0.70-0.94, chi2=7.70, d.f.=1, P=0.006] but not of cardiac events. It should not be assumed that one summary measure of ambulatory blood pressure would be the best predictor of different clinical outcomes.

Awake Systolic Blood Pressure Variability Correlates With Target-Organ Damage in Hypertensive Subjects

Growing evidence associates blood pressure (BP) variability with cardiovascular events in hypertensive patients. Here we tested the existence of a relationship between awake BP variability and target-organ damage in subjects referred for suspected hypertension. Systolic and diastolic BP variability were assessed as the standard deviation of the mean out of 24-hour, awake and asleep BP recordings in 180 untreated subjects, referred for suspected hypertension. Measurements were done at 15-minute intervals during daytime and 30-minute intervals during nighttime. Left ventricular mass index (by echo), intima-media thickness (by carotid ultrasonography), and microalbuminuria were assessed as indices of cardiac, vascular and renal damage, respectively. Intima-media thickness and left ventricular mass index progressively increased across tertiles of awake systolic BP variability (P for trend=0.001 and 0.003, respectively). Conversely, microalbuminuria was similar in the 3 tertiles (P=NS). Multivariable analysis identified age (P=0.0001), awake systolic BP (P=0.001), awake systolic BP variability (P=0.015) and diastolic BP load (P=0.01) as independent predictors of intima-media thickness; age (P=0.0001), male sex (P=0.012), awake systolic (P=0.0001) and diastolic BP (P=0.035), and awake systolic BP variability (P=0.028) as independent predictors of left ventricular mass index; awake systolic BP variability (P=0.01) and diastolic BP load (P=0.01) as independent predictors of microalbuminuria. Therefore, awake systolic BP variability by non-invasive ambulatory BP monitoring correlates with sub-clinical target-organ damage, independent of mean BP levels. Such relationship, found in subjects referred for recently suspected hypertension, likely appears early in the natural history of hypertension.

Predictors of All-Cause Mortality in Clinical Ambulatory Monitoring

The prognostic value of sleep blood pressure reported by recent studies is variable. Our aim was to examine the relationship of sleep blood pressure, measured by 24-hour ambulatory blood pressure monitoring, with all-cause mortality. We studied a cohort of 3957 patients aged 55+/-16 (58% treated) referred for ambulatory monitoring (1991-2005). Sleep, including daytime sleep, was recorded by diary. Linkage with the national population register identified 303 deaths during 27 750 person-years of follow-up. Hazard ratios (HRs) for mortality in Cox proportional hazards models that included age, sex, hypertension, and diabetes treatment were 1.32 (95% CI: 0.99 to 1.76) for awake hypertension (>or=135/85 mm Hg), and 1.67 (95% CI: 1.25 to 2.23) for sleep hypertension (>or=120/70 mm Hg). By quintile analysis, the upper fifths of systolic and diastolic dipping during sleep were associated with adjusted HRs of 0.58 (95% CI: 0.41 to 0.82) and 0.68 (95% CI: 0.48 to 0.96), respectively. In a model controlling for awake systolic blood pressure, hazards associated with reduced systolic dipping increased from dippers (>10%; HR: 1.0), through nondippers (0% to 9.9%; HR: 1.30; 95% CI: 1.00 to 1.69) to risers (<0%; HR: 1.96; 95% CI: 1.43 to 2.96). Thus, in practice, ambulatory blood pressure predicts mortality significantly better than clinic blood pressure. The availability of blood pressure measures during sleep and, in particular, the pattern of dipping add clinically predictive information and provide further justification for the use of ambulatory monitoring in patient management.

Cardiovascular and metabolic effects of CPAP in obese males with OSA

Obstructive sleep apnoea is associated with increased blood pressure and other features of the metabolic syndrome. The aim of the present study was to determine the relative effectiveness of continuous positive airway pressure (CPAP) in modifying these outcomes. A randomised placebo-controlled blinded crossover trial comparing cardiovascular and metabolic outcomes after 6 weeks of therapeutic and sham CPAP was performed in 34 CPAP-naïve patients (mean+/-SD body mass and respiratory disturbance indices were 36.1+/-7.6 and 39.7+/-13.8, respectively). Mean waking systolic and diastolic blood pressure fell by 6.7 and 4.9 mmHg, respectively, when compared with sham CPAP. No change was observed in glucose, lipids, insulin resistance or the proportion of patients with metabolic syndrome. In CPAP-compliant patients the fall in blood pressure was greater and the baroreceptor sensitivity improved significantly but no metabolic variable changed. In obese Caucasians with untreated obstructive sleep apnoea, continuous positive airways pressure can improve baroreceptor responsiveness and reduce waking blood pressure within 6 weeks, but this treatment period was insufficient to modify insulin resistance or change the metabolic profile. The mechanisms underlying this difference in the time course of blood pressure and metabolic response to continuous positive airway pressure in obstructive sleep apnoea requires further exploration.

Infradian awake and asleep systolic and diastolic blood pressure rhythms in humans

Blood pressure shows 24-h rhythms with a significant seasonal fluctuation. To characterize 2-month to 12-month infradian rhythms in the mean awake and asleep systolic blood pressure (SBP) and diastolic blood pressure (DBP) in humans. A total of 1689 participants underwent 24-h ambulatory blood pressure monitoring during different periods of the year. The mean daily temperature, humidity, barometric pressure and wind velocity values for the same time span and geographical location were obtained. Fourier analysis was used to fit 12-month, 6-month, 4-month, 3-month and 2-month rhythms to the mean awake and asleep SBP and DBP and to metereological variables. The awake mean SBP and DBP values showed significant 12-month and 3-month rhythms (respectively, R2 = 55%, P < 0.001 and R2 = 45% P < 0.001), with a peak in July (winter) and a trough-peak difference of 6.2 +/- 1.6 mmHg (P < 0.001, SBP) and 4.2 +/- 1.5 mmHg (P < 0.001, DBP). In contrast, asleep blood pressure means showed mainly 3-month rhythms (SBP, R2 = 19%, P < 0.02; DBP, R2 = 43% P < 0.02). Mean daily temperature and humidity showed at 12-month, 6-month, 4-month, 3-month and 2-month rhythms, barometric pressure showed 12-month and 6-month rhythms, and wind velocity showed 12-month and 3-month rhythms. Minimal temperature values and maximal humidity values coincided with elevated blood pressure values. Awake blood pressure means exhibited mainly circannual fluctuations while asleep blood pressure means showed principally 3-month rhythms. Infradian blood pressure variations correlated with some meteorological variables.