Relation of extent of nocturnal blood pressure decrease to cardiovascular remodeling in never-treated patients with essential hypertension

Clinical impact of dipping and nocturnal blood pressure patterns in newly diagnosed, never-treated patients with essential hypertension

The significance of nondipping and increased nighttime systolic blood pressure (SBP) in established hypertension is well defined. We investigated whether these factors alone or combined correlate with vascular damage in early-stage hypertension. Newly diagnosed, untreated hypertensives were classified as dippers and nondippers according to ambulatory blood pressure (BP). Twenty-four-hour urinary albumin excretion and markers of arterial stiffness (pulse wave velocity, augmentation index, central and peripheral pulse pressure, central BP) and atherosclerosis (carotid intima-media thickness) were assessed. Serum asymmetric dimethylarginine, an index of endothelial dysfunction, was measured in a study subgroup; 10-year cardiovascular risk was calculated. Among 222 hypertensives, only urinary albumin excretion was increased in nondippers, compared to dippers (P = .026). When dippers were further stratified according to nighttime SBP (<120 or ≥120 mm Hg), the first group demonstrated the lowest levels of office, aortic, 24-hour, daytime and nighttime BP, compared to dippers with elevated nighttime SBP and nondippers. Although vascular measurements and asymmetric dimethylarginine were comparable between these groups, dippers with normal nighttime SBP exhibited the lowest cardiovascular risk score (P = .050). In early-stage hypertension, nondipping was accompanied by microvascular, yet not macrovascular and endothelial dysfunction. Dippers with elevated nighttime SBP appear as a distinct group with increased hemodynamic pressure load and cardiovascular risk.

Ambulatory Pulse Pressure Predicts the Development of Left Ventricular Diastolic Dysfunction in Over 20 Years of Follow-up

BACKGROUND

Ambulatory blood pressure (ABP) has been shown to have an association with left ventricular diastolic dysfunction (LVDD) in cross-sectional assessments. We evaluated the association between ABP measurement (ABPM) and the development of LVDD during over 20 years of follow up in 414 middle-aged subjects from OPERA cohort.

METHODS

ABPM, clinical, and anthropometric measurements were performed in baseline. Echocardiographic measurements were performed at baseline and during follow-up and E/E' ≥15 was considered indicating significant LVDD.

RESULTS

Several baseline clinical characteristics (age, female gender, short stature, body mass index, prevalence of diabetes, in-office systolic BP (SBP), in-office pulse pressure (PP), N-terminal pro-atrial natriuretic peptide, and the use of antihypertensive therapy) were associated with the development of LVDD. Baseline 24-hour mean, daytime mean or nighttime mean SBP or diastolic BP were not associated with the development of LVDD, neither were different circadian BP profiles. Instead 24-hour mean, daytime mean and nighttime mean PP showed significant association with the development of LVDD (P from <0.001 to 0.001) even after adjustment with significant baseline clinical characteristics (P from 0.001 to 0.016).

CONCLUSION

These findings suggest that ambulatory PP has an independent predictive value in the development of LVDD during over 20 years of follow-up.

Not nondipping but nocturnal blood pressure predicts left ventricular hypertrophy in the essential hypertensive patients: the Korean Ambulatory Blood Pressure multicenter observational study

OBJECTIVE

The aim of this study was to investigate whether nocturnal blood pressure (BP), established on the basis of a single 24-h BP monitoring, is a stronger predictor of left ventricular hypertrophy (LVH) compared with nondipping status in the essential hypertensive patients.

METHODS

A total of 682 hypertensive patients (mean age 56.1 ± 14.5 years, 50.7% women) who underwent echocardiography were enrolled. 'Nondipping status' was defined as a nocturnal SBP fall less than 10% of daytime mean SBP. LVH was defined as a left ventricular mass index exceeding 54.0 g/m in men and 53.0 g/m in women. Each patient was categorized in three groups according to the total cardiovascular risk using 2007 European Society of Hypertension/ European Society of Cardiology guidelines as average or low, moderate, and high or very high added risk.

RESULTS

Among 682 participants, 184 (26.9%) showed LVH on echocardiography. The proportion of individuals with high or very high added cardiovascular risk profile was 356 (52.1%). In multiple logistic regression analysis, age 56 years at least [odds ratio (OR) 1.047, 95% confidence interval (CI) 1.031-1.063, P < 0.0001], female participants (OR 1.751, 95% CI 1.172-2.616, P = 0.0062), BMI higher than 24.6 kg/m (OR 1.178, 95% CI 1.110-1.250, P < 0.0001), smoking (OR 1.793, 95% CI 1.028-3.127, P = 0.0397), and nocturnal SBP at least 127 mmHg (OR 1.032, 95% CI 1.009-1.055, P = 0.0059) were significant independent predictors for LVH whereas nondipping was not (OR 0.857, 95% CI 0.481-1.528, P = 0.6013).

CONCLUSION

These findings suggest that nocturnal BP rather than nondipping may be a better predictor of LVH, especially in secondary or tertiary referral hospital setting targeting relatively high cardiovascular risk patients.

Non-Dipping Pattern and Subclinical Cardiac Damage in Untreated Hypertension: A Systematic Review and Meta-Analysis of Echocardiographic Studies

AIM

The association of non-dipping (ND) pattern with cardiac damage is debated. We performed a meta-analysis in order to provide comprehensive information on subclinical cardiac alterations in untreated ND hypertensives.

DESIGN

A computerized search was performed using PubMed, OVID, EMBASE, and Cochrane library databases from 1 January 1990 up to 31 October 2014. Full articles published in English language providing data on subclinical cardiac damage in ND as compared to dipper (D) hypertensives, as assessed by echocardiography, were considered.

RESULTS

A total of 3,591 untreated adult subjects (1,291 ND and 2,300 D hypertensives) included in 23 studies were considered. Left ventricular (LV) mass index (LVMI) was higher in ND than in D hypertensives (122±3.8 g/m2 vs. 111±3.3 g/m2, standardized mean difference, SMD: 0.40±0.07, confidence interval (CI): 0.26-0.53, P < 0.001); relative wall thickness (RWT) and left atrium (LA) diameter were greater (SMD: 0.14±0.005, CI: 0.05-0.23, P = 0.002; 0.36±0.10, CI: 0.16-0.56, P < 0.001, respectively), while mitral E/A ratio was lower in ND than in D counterparts (SMD: -0.23±0.08, CI: -0.39 to -0.08, P = 0.003). After assessing data for publication bias, the difference between groups was still significant, with the exception of E/A ratio.

CONCLUSIONS

Our meta-analysis supports an association between ND pattern and increased risk of LV structural alterations in untreated essential hypertensives. This observation supports the view that an effective BP control throughout the entire 24-hour cycle may have a key role in preventing or regressing subclinical cardiac damage associated to ND pattern.

Cross-sectional study of indices of dynamic components of ambulatory blood pressure and cardiac damage in elderly male patients with essential hypertension

BACKGROUND AND AIMS

Blood pressure control is closely related to target organ damage in elderly patients with hypertension. The aim of this study was to determine the relationship between ambulatory blood pressure monitoring (ABPM) indices and cardiac damage in elderly male patients with treated essential hypertension (EH).

METHOD

This study included 998 Chinese men (mean age, 78.44 ± 12.02 years) with EH. Participants underwent cardiac function assessment, laboratory testing, and ABPM, including ABP, BP variability, BP circadian rhythms, and hypertensive or hypotensive time indices. The relationships between ABPM indices and cardiac damage (expressed by shape and function) were assessed using ridge regression analysis.

RESULTS

Ridge regression analysis revealed the following after adjustments for age, common cardiovascular risk factors, disease, and medications: N-terminal fragment pro-B-type natriuretic peptide was negatively correlated with the diastolic blood pressure nocturnal fall rate; the peak early/atrial velocity (E/A) ratio E/A ratio was negatively correlated with the 24 h mean systolic blood pressure (24 hmSBP), daytime SBP (dSBP), and nocturnal SBP (nSBP); and ejection fraction (EF) was negatively correlated with 24 h SBP percent time of elevation (24 hSBP PTE %) and 24 h DBP percent time of elevation (24 hDBP PTE %). Left ventricular mass (LVM) was positively correlated with the 24 hmSBP, dSBP, nSBP, 24 h mean pulse pressure (24 hmPP), day mean pulse pressure, and nocturnal mean arterial pressure, whereas LVM was negatively correlated with the NDBPF.

CONCLUSIONS

Our study showed that the ABPM indices associated with cardiac damage may be regarded as an early predictive marker for cardiac function impairment in elderly male patients with EH.

Comparison of subclinical left and right ventricular systolic dysfunction in non-dipper and dipper hypertensives: impact of isovolumic acceleration

Abstract Objectives: To evaluate subclinical left ventricular and right ventricular systolic impairment in dipper and non-dipper hypertensives by using isovolumic acceleration.

METHODS

About 45 normotensive healthy volunteers (20 men, mean age 43 ± 9 years), 45 dipper (27 men, mean age 45 ± 9 years) and 45 non-dipper (25 men, 47 ± 7 years) hypertensives were enrolled. Isovolumic acceleration was measured by dividing the peak myocardial isovolumic contraction velocity by isovolumic acceleration time.

RESULTS

Non-dippers indicated lower left ventricular (2.2 ± 0.4 m/s(2) versus 2.8 ± 1.0 m/s(2), p < 0.01) and right ventricular isovolumic acceleration values (2.8 ± 0.8 m/s(2) versus 3.5 ± 1.0 m/s(2), p = 0.012) compared with dippers. Left ventricular mass index (p = 0.001), interventricular septal thickness (p = 0.002) and myocardial performance index (p < 0.001) were negatively correlated with left ventricular isovolumic acceleration. Left ventricular septal thickness (p = 0.002), mass index (p = 0.001) and right ventricular myocardial performance index (p < 0.001) were negatively correlated with right ventricular isovolumic acceleration.

CONCLUSION

The present study demonstrates that non-dipper hypertensives have increased left and right ventricular subclinical systolic dysfunction compared with dippers. Isovolumic acceleration is the only echocardiographic parameter in predicting this subtle impairment.

Nocturnal hypertension and organ damage in dippers and nondippers

BACKGROUND

The relationship between high nocturnal blood pressure (BP), organ damage and the dipping/nondipping status is poorly defined. We investigated whether a consistent dipping/nondipping pattern defined on the basis of two 24-h ambulatory BP monitorings (ABPMs) is associated with subclinical organ damage in untreated hypertensive patients with elevated nighttime BP.

METHODS

All subjects underwent the following procedures: cardiac and carotid ultrasonography, 24-h urine collection for microalbuminuria (MA), and ABPM over two 24-h periods within 4 weeks. Nocturnal hypertension was defined according to current guidelines (i.e., nighttime systolic BP (SBP) ≥120 and/or diastolic BP ≥70 mm Hg) and nondipping status as an average reduction in SBP at night <10% compared with day-time values.

RESULTS

Among 343 subjects, 199 were dippers and 144 nondippers. No differences were found in clinical variables, average 48-h BP, left ventricular mass, carotid intima-media (IM) and urinary albumin excretion between the groups. This was also the case for prevalence rates of left ventricular hypertrophy, carotid IM thickening or plaque and MA. Finally, no relationship was found between the markers of organ damage and BP fall at night.

CONCLUSIONS

In the presence of nocturnal hypertension, dippers have a similar subclinical cardiac and extra-cardiac organ damage as their nondipper counterparts. These data suggest that therapeutic strategies only addressing the nondipper pattern may be insufficient to protect hypertensive subjects against the dangerous effects of elevated nocturnal BP.American Journal of Hypertension, (2012); doi:10.1038/ajh.2012.49.

Nocturnal blood pressure in untreated essential hypertensives

AIM. Prevalence, correlates and reproducibility of nocturnal hypertension (NH) as defined by fixed cut-off limits in uncomplicated essential hypertension are poorly defined. Therefore, we assessed such issue in a cohort of 658 untreated hypertensives. METHODS. All subjects underwent procedures including cardiac and carotid ultrasonography, 24-h urine collection for microalbuminuria, ambulatory blood pressure monitoring (ABPM), over two 24-h periods within 4 weeks. NH was defined according to current guidelines (i.e. night-time blood pressure, BP ? 120/70 mmHg) and non-dipping status as a reduction in average systolic (SBP) and diastolic BP (DBP) at night lower than 10% compared with daytime values. RESULTS. A total of 477 subjects showed NH during the first and second ABPM period; 62 subjects had normal nocturnal BP (NN) in both ABPM sessions. Finally, 119 subjects changed their pattern from one ABPM session to the other. Overall, 72.5% of subjects had reproducible NH, 18% variable pattern (VP) and 9.5% reproducible NN. In the same group, figures of reproducible non-dipping, variable dipping and reproducible dipping pattern were 24%, 24% and 52%, respectively. Among NH patients, 56% of whom were dippers, subclinical cardiac organ damage was more pronounced than in their NN counterparts. CONCLUSIONS. In uncomplicated essential hypertensives, NH is a more frequent pattern than non-dipping; NH is associated with organ damage, independently of dipping/non-dipping status. This suggests that options aimed at restoring a blunted nocturnal BP fall may be insufficient to prevent cardiovascular complications unless night-time BP values are fully normalized.

Nocturnal non‐dipping pattern in untreated hypertensives at different cardiovascular risk according to the 2003 ESH/ESC guidelines

AIM

To evaluate in a large population of untreated, uncomplicated essential hypertensives the relationship between alterations in nocturnal blood pressure (BP) profile, i.e. non-dipping pattern, and total cardiovascular risk.

METHODS

A total of 580 consecutive patients with grade 1 or 2 hypertension, referred to our outpatient clinic, underwent the following procedures: (i) clinical and routine laboratory examinations; (ii) 24-h ambulatory BP monitoring; (iii) 24-h collection for microalbuminuria; (iv) echocardiography; and (v) carotid ultrasonography. Cardiovascular risk was assessed according to the stratification scheme suggested by the 2003 ESH/ESC guidelines.

RESULTS

According to this classification, 16.2% of the 580 patients were considered at low added risk, 42.4% at medium added risk and 41.4% at high added risk; 38.5% of the overall population was classified in the high-risk stratum because of at least one manifestation of target organ damage (TOD) and 6.3% for the presence of three or more risk factors. The prevalence rates of a non-dipping pattern (decrease in BP at night < or = 10% compared with the average daytime values) were 28.5% in low-risk, 32.6% in medium-risk and 42.2% in high-risk patients, respectively. CONCLUSIONS. Our findings show that the prevalence of a non-dipping profile is significantly greater in patients stratified at high compared with those at low and medium added risk.

Coronary flow reserve in dipper and non‐dipper hypertensive patients

BACKGROUND

Failure to decrease blood pressure (BP) normally during night-time, which is called non-dipping, in hypertensive individuals is associated with higher cardiovascular morbidity and mortality. In addition, non-dipping BP leads to structural changes in the left ventricle; however, the effect of non-dipping BP on coronary flow reserve (CFR) has not been studied yet.

METHODS

In this study, we measured CFR of 22 subjects with non-dipper hypertension, and 15 subjects with dipper hypertension using transthoracic second-harmonic Doppler echocardiography (Acuson Sequoia C256. None of the subjects had any systemic disease or coronary risk factor except hypertension.

RESULTS

Age, gender, body mass index, lipids and echocardiographic findings including left ventricular mass index were similar between the groups. Office BP recordings were similar between non-dipper and dipper groups (147.9+/-6.1/93.9+/-4.3 vs 144.0+/-8.0/93.0+/-3.7). Daytime and 24-h ambulatory BP measurements were similar within the groups, but night-time BPs were significantly greater in non-dipper group than those were in dipper group. Left ventricular diastolic and systolic functions, and both baseline and hyperemic peak diastolic coronary velocity as well as CFR, were similar between the non-dipper and dipper groups (CFR: 2.47+/-0.59 vs 2.39+/-0.47).

CONCLUSION

CFR were similar in patients with non-dipper and dipper hypertension in the absence of excessive left ventricular hypertrophy and other cardiovascular risk factors.

The effects of nocturnal dipping on cardiovascular outcomes and proteinuria in essential hypertensive patients

Individuals who do not have a 10% to 20% reduction in blood pressure (BP) during the night are known as ‘nondippers’. Non-dipping patterns in hypertensive patients have been shown to be associated with an excess of target organ damage and other adverse outcomes. The present study was designed to investigate the relationship between nocturnal BP pattern, defined on the basis of the ambulatory blood pressure monitoring (ABPM) recording, and cardiac and renal target organ damage in a population of at least one year treated essential hypertensive subjects. The present analysis involved 123 patients with treated essential hypertension attending the outpatient clinic of our centre. Each patient was subjected to the following procedures: blood sampling for routine blood chemistry, spot urine for proteinuria, 24-hour periods of ABPM, and echocardiography. In the ABPM period, a dipping pattern was observed in 65 of the 123 patients, and a non-dipping pattern in 58 patients. Body mass index was higher in the non-dippers (26 ± 4 versus 28 ± 4, p<0.05). The proteinuria in spot urine was significantly higher in the non-dippers (10 ± 6 versus 24 ± 48, p<0.03). Left ventricular mass, interventricular septum thickness, posterior wall thickness and left ventricular systolic diameter were significantly higher in the non-dippers compared to the dippers. Left ventricular diastolic function was similar in non-dipper cases, except E-wave deceleration time. In treated essential hypertensives the blunted or absent nocturnal fall in blood pressure can be a strong predictor of cardiac and renal events. Hypertensive patients should be evaluated by ambulatory blood pressure monitoring. To prevent patients at risk for morbidity and mortality casualities as a result of hypertension, patients should be evaluated by ambulatory blood pressure monitoring. This method can be utilized for exacting future follow-ups with the patient.

Prevalence and Correlates of Left Ventricular Hypertrophy in the African American Study of Kidney Disease Cohort Study

African Americans with hypertensive renal disease represent a high-risk population for cardiovascular events. Although left ventricular hypertrophy is a strong predictor of adverse cardiac outcome, the prevalence and associated factors of left ventricular hypertrophy in this patient population are not well described. The African American Study of Kidney Disease Cohort Study is a prospective, observational study that is an extension of the African American Study of Kidney Disease randomized clinical trial that was conducted from 1994 to 2001 in African Americans with hypertension and mild-to-moderate renal dysfunction. Echocardiograms and 24-hour ambulatory blood pressure monitoring were performed at the baseline visit of the cohort. Of 691 patients enrolled in the cohort study, 599 patients had interpretable baseline echocardiograms and ambulatory blood pressure data. Left ventricular hypertrophy was defined using a cut point for left ventricular mass index >49.2 g/m 2.7 in men and >46.7 m/m 2.7 in women. The majority of patients had left ventricular hypertrophy (66.7% of men and 73.9% of women). In a multiple regression analysis, higher average day and nighttime systolic blood pressure, younger age, and lower predicted glomerular filtration rate were associated with left ventricular hypertrophy, but albuminuria was not. These data demonstrate a striking prevalence of left ventricular hypertrophy in the African American Study of Kidney Disease Cohort and identify potential targets for prevention and therapeutic intervention in this high-risk patient population.

Reproducibility of dipping/nondipping pattern in untreated essential hypertensive patients: impact of sex and age

OBJECTIVE

We aimed to evaluate the intrasubject short-term reproducibility of nocturnal blood pressure patterns (dipping/nondipping) in essential hypertensive patients in relation to age (<50 and > or =50 years) and sex.

METHODS

A total of 619 never-treated essential grade 1 and 2 hypertensive patients (383 men, 236 women) underwent the following procedures: (1) repeated clinic blood pressure measurements, (2) routine examinations, (3) ambulatory blood pressure monitoring over two 24-h periods within 4 weeks. Dipping pattern was defined as a 10%, or more, reduction in average systolic blood pressure/ diastolic blood pressure at night compared to daytime values.

RESULTS

Of the 407 patients showing a dipping pattern during the first ambulatory blood pressure monitoring period, 329 (80.1%) had the same pattern during the second ambulatory blood pressure monitoring recording. Of the 212 patients with a nondipping pattern during the first ambulatory blood pressure monitoring period, 140 (65.9%) confirmed the same pattern during the second ambulatory blood pressure monitoring period. Overall, 149 patients (24.1%) changed their initial nocturnal pattern at the second ambulatory blood pressure monitoring recording, without significant age and sex-related differences. Lower reproducibility rates of the nondipping as compared to the dipping pattern were found in the whole population as well as in men regardless of age and in younger but not in older women.

CONCLUSIONS

These findings indicate that nocturnal blood pressure patterns have a limited short-term reproducibility in the whole study population as well as in different age and sex subgroups. As variability of nocturnal blood pressure patterns is not predicted by easy available clinical data, such as sex and age, a reliable classification of patients according to circadian blood pressure patterns should be obtained by repeating ambulatory blood pressure monitoring.

Circadian blood pressure variation: relationship between dipper status and measures of arterial stiffness

BACKGROUND

Compared with dippers, hypertensive individuals with a nondipping nocturnal blood pressure (BP) profile have more target organ damage and a worse cardiovascular prognosis, potentially mediated through arterial stiffness.

OBJECTIVE

To examine arterial stiffness and dipping in a population of 314 untreated hypertensive individuals, mean age 48 +/- 8 years, 55% men.

METHODS

Dipping was defined as a 10-20% fall in nocturnal BP; extreme dipping as greater than 20%, nondipping as less than 10%, and reverse-dipping as 0% at most fall in nocturnal BP. Aortic pulse wave velocity (PWV) (Complior) and augmentation index (Sphygmocor) were measured.

RESULTS

Groups did not differ by age, gender, 24-h or daytime mean BP, body mass index, smoking, cholesterol, glucose, renin or aldosterone. The relationship between PWV and dipper-status was J-shaped, with extreme-dippers and reverse-dippers having the highest PWV. Nondippers and reverse-dippers had significantly higher age and sex-adjusted PWV compared with dippers. Following multivariate adjustment for age, gender, mean arterial pressure, heart rate and smoking, reverse-dippers had significantly higher PWV than either dippers or nondippers (P = 0.005 and P = 0.006, respectively). Dipper status was not associated with augmentation index.

CONCLUSIONS

A reverse-dipper pattern, corresponding to the 95% percentile of the night: day BP ratio on ambulatory BP monitoring, identifies a population group with increased PWV. This difference could not be explained by the measured risk factors. Reverse-dippers had significantly less day: night variability in heart rate and wider pulse pressures at night than any of the other groups, suggesting altered sympathetic tone at night as a potential mechanism.

Night-time blood pressure patterns and target organ damage: a review

BACKGROUND

Individuals who do not have a 10% to 20% reduction in blood pressure (BP) during the night are known as 'nondippers'. The cause of this nondipping phenomenon is not fully understood; however, there is a growing body of evidence linking a nondipping BP pattern with target organ damage.

OBJECTIVE

To review the literature and present an overview of the target organ damage found to be associated with a nondipping BP pattern.

METHODS

PubMed, CINAHL and Medscape searches of all available English language articles from 1986 to 2005 were performed. Search terms included 'BP nondipping', 'BP dipping' and 'target organ damage'.

RESULTS

There is evidence to suggest that individuals with hypertension who exhibit a nondipping BP profile are at higher risk of cardiac and extracardiac morbidity and mortality. In particular, nondippers with essential hypertension have been found to have more advanced left ventricular hypertrophy, left ventricular mass and left ventricular mass index, carotid artery wall thickness, carotid artery atherosclerotic plaques, silent cerebral infarct, stroke, cognitive impairment and microalbuminuria.

CONCLUSION

A better understanding of the importance of the circadian variations of BP may help to identify those at higher risk of cardiovascular morbidity and mortality, as well as lay the foundation for interventions to prevent/treat alterations in night-time BP patterns.

Ambulatory arterial stiffness index is not a specific marker of reduced arterial compliance

Ambulatory arterial stiffness index (AASI), a measure based on the relative behavior of 24-hour systolic and diastolic blood pressure (BP), has been suggested as a marker of arterial stiffness and a predictor of cardiovascular mortality. However, a narrow range of diastolic BP values over the 24 hours tends to flatten the regression slope and to artificially increase AASI. We explored the possible influence of different ranges of 24-hour diastolic BP fluctuations, such as those related to nocturnal BP fall, on AASI, and on its relationship with target organ damage. In 515 untreated hypertensive patients, AASI was directly related to age (r=0.30) and 24-hour systolic BP (r=0.20), whereas it was inversely related with nocturnal systolic and diastolic BP reduction (r=-0.28 and -0.46, respectively; all P<0.001). A direct relationship was found between AASI and left ventricular mass index (r=0.17; P<0.001), but this relation was no longer significant after adjustment for age, sex, body mass index, daytime systolic BP, and day-night systolic BP reduction (all P<0.05). AASI was directly related to carotid-femoral pulse wave velocity, an intrinsic measure of aortic stiffness (r=0.28; P<0.001), but no independent relation was found in a multiple linear regression. Our conclusions are as follows: (1) AASI is strongly dependent on the degree of nocturnal BP fall in hypertensive patients; (2) there is no significant relation between AASI and left ventricular mass after proper adjustment for confounders; and (3) the relation between AASI and a widely accepted measure of aortic stiffness, such as pulse wave velocity, is weak and importantly affected by other factors.

Nondipping blood pressure patterns among individuals with essential hypertension: a review of the literature

BACKGROUND

Researchers have discovered that blood pressure (BP) varies in a diurnal manner throughout a 24-hour period, being higher during the day and lower at night. Most people have a dipping BP pattern characterized by a nighttime BP that is 10-20% lower than their daytime BP. Individuals who experience a less than 10% reduction in nighttime BP are described as having a nondipping BP pattern. Although controversial, there is a growing body of evidence suggesting that a nondipping BP pattern is associated with a greater risk of target organ damage among individuals with essential hypertension.

AIM

To review the literature on the most common factors associated with nondipping BP patterns among individuals with essential hypertension.

METHODS

CINAHL (1982-March 2006), PubMed (1950-March 2006) and Cochrane Library (1966-March 2006) databases were searched using the keywords: dipper, dipping, nondipper, nondipping, ambulatory blood pressure monitoring, ABPM, hypertension, essential hypertension, high blood pressure, blood pressure, nocturnal blood pressure, nighttime blood pressure, diurnal blood pressure, and blood pressure patterns. Published studies, abstracts, dissertations as well as the reference lists of retrieved articles were reviewed. Studies were included if they involved subjects with only treated or untreated essential hypertension or those with samples of both nomotensive and treated or untreated essential hypertensive individuals. Additionally, studies needed to evaluate 24-hour, daytime and nighttime BP patterns.

RESULTS

There is some evidence to suggest advanced age, African-American ethnicity, female sex, postmenopausal status, sodium sensitivity, sleep apnea, sleep quality, anger, hostility, depression, stress, social support, and socioeconomic status have an association with nondipping BP patterns.

CONCLUSION

Knowledge of the potential factors associated with an altered nighttime BP pattern is of importance because it can help identify persons at risk for nondipping BP patterns and potential target organ damage. Furthermore, knowledge of these factors associated with a nondipping BP profile will lay the foundation for interventions to prevent/treat alterations in nighttime BP patterns.

Estimation of an age-specific reference interval for pulse wave velocity: a meta-analysis

OBJECTIVE

To estimate an age-specific reference interval for carotid-femoral pulse wave velocity (PWV), an index of aortic stiffness, and to determine the predictive values of the reference range for detecting those at moderate and high risk of cardiovascular disease (CVD).

DESIGN AND METHODS

We searched MEDLINE using PubMed from 1995 to 2005 for all studies in which Carotid-Femoral PWV was measured using a Complior (Colson, Paris, France) apparatus in Caucasian non-pregnant adults. Twenty-five studies were included, covering 30 groups of subjects; these groups were classified a priori into low (normal), moderate, and high CVD risk categories, with 2008, 5979, and 180 (total 8167) subjects, respectively. Individual-level data were simulated for each group, and an age-specific reference interval was calculated by using fractional polynomial functions.

RESULTS

We plotted an age-adjusted normal curve for PWV with 2.5, 5, 50, 90, 95, and 97.5 centile limits. Applying this reference interval to the moderate- and high-risk groups using simulations yielded sensitivities of 34.3 [95% confidence interval (CI) 33.2-35.3] and 57.2 (95% CI 55.2-59.3), respectively, specificities of 95.3 (95% CI 94.8-95.8) and 95.3 (95% CI 94.4-96.2), respectively, and positive likelihood ratios of 7.3 and 12.2, respectively.

CONCLUSION

We constructed an age-adjusted reference curve for PWV. Using the 95th centile of this curve as a threshold (e.g. 10.94, 11.86, and 13.18 m/s for 20, 40, and 60 years old) shows construct validity, as it appears to identify medium and high CVD risk groups reasonably accurately. This reference range needs to be tested using other datasets.

Reproducibility of nocturnal blood pressure fall in early phases of untreated essential hypertension: a prospective observational study

A number of studies have shown that a smaller than normal nocturnal blood pressure (BP) decrease is associated with cardiovascular disease. However, no large prospective studies have examined the reliability of nocturnal dipping within individuals. The aim of our study was to investigate the short-term variability of nocturnal BP fall in a large cohort of patients with recently diagnosed essential hypertension. In all, 414 uncomplicated never treated hypertensive patients referred to our outpatient hypertension hospital clinic (mean age 46+/-12 years; 257 M, 157 F) prospectively underwent: (1). repeated clinic BP measurements; (2). routine examinations recommended by WHO/ISH guidelines; and (3). ambulatory BP monitoring (ABPM) twice within a 4-week period. Dipping pattern was defined as a reduction in the average systolic and diastolic BP at night greater than 10% compared to average daytime values. Overall, 311 patients (75.1%) showed no change in their diurnal variations in BP. Of the 278 patients who had a dipping pattern on the first ABPM, 219 (78.7%) confirmed this type of profile on the second ABPM, while 59 (21.3%) showed a nondipping pattern. Among 37 dipper patients with >20% of nocturnal systolic BP decrease (extreme dippers), only 16 (43.2%) had this marked fall in BP on the second ABPM. Of the 136 patients who had a nondipping pattern on the first ABPM, 92 (67.6%) confirmed their initial profile on the second ABPM, while 44 (32.4%) did not. Patients with reproducible nondipping profile were older (48+/-12 years) than those with reproducible dipping profile (44+/-12 years, P<0.05). These findings indicate that: (1). short-term reproducibility of nocturnal fall in BP in untreated middle-aged hypertensives is rather limited: overall, one-fourth of patients changed their initial dipping patterns when they were studied again after a few weeks; (2). this was particularly true for extreme dipping and nondipping patterns; (3). abnormalities in nocturnal BP fall, assessed by a single ABPM, cannot be taken as independent predictors of increased cardiovascular risk.

Arterial stiffness and the systolic hypertension syndrome

PURPOSE OF REVIEW

This review is intended to provide the background for a new comprehensive hemodynamic view of the syndrome of systolic or wide pulse pressure hypertension and its hallmark abnormality: increased central arterial stiffness.

RECENT FINDINGS

Studies of the pathogenesis of systolic hypertension have lagged. This review describes the systolic hypertension syndrome as a complex set of hemodynamic maladaptations that include stiff central arteries, normal peripheral arteries with variable pressure amplification characteristics, arteriolar constriction, microcirculatory rarefaction, metabolic abnormalities, cardiac hypertrophy, and increased blood pressure variability. Because the structural and functional properties of arteries of different caliber are highly heterogeneous and vary with aging and disease, simple measurements such as standard brachial artery blood pressure, brachial pulse pressure, or mean arterial pressure are inadequate to provide meaningful insight into the pathophysiology of the syndrome. Additional parameters developed to describe changes in arterial mechanics (arterial compliance or stiffness, elastic modulus, impedance, pulse wave velocity, augmentation index, and pulse pressure amplification) are intrinsically limited and are directly or indirectly pressure-dependent. Quantitation of central arterial stiffness provides a modest increment in cardiovascular and renal risk stratification.

SUMMARY

Better clinical management of systolic hypertension depends on greater insight into the syndrome as a whole, more critical analysis of existing techniques, and the development of new approaches.

Cardiovascular target organ damage in essential hypertensives with or without reproducible nocturnal fall in blood pressure

OBJECTIVE

The clinical significance of classifying patients as dippers and non-dippers on the basis of a single period of ambulatory blood pressure monitoring (ABPM) has been questioned. The aim of this study was to evaluate the relationship between nocturnal dipping status, defined on the basis of two periods of ABPM, and cardiac and extracardiac target organ damage in essential hypertension.

METHODS

A total of 375 never-treated essential hypertensive patients [mean 24-h blood pressure (BP) > or = 125/80 mmHg; mean +/- SD age 45.9 +/- 11.9 years] referred for the first time to our outpatient clinic underwent the following procedures: (i) repeated clinic BP measurements; (ii) blood sampling for routine chemistry examinations; (iii) 24-h urine collection for microalbuminuria; (iv) ABPM over two 24-h periods within 4 weeks; (v) echocardiography; and (vi) carotid ultrasonography.

RESULTS

A reproducible nocturnal dipping (decrease in BP > 10% from mean daytime BP in both ABPM periods) and non-dipping profile (decrease in BP < or = 10% in both ABPM periods) was found in 199 (group I) and 79 patients (group II), respectively; 97 patients (group III) had a variable dipping profile. The three groups did not differ with regard to age, gender, body mass index, clinic BP, 48-h BP and heart rate. Left ventricular mass index, interventricular septum thickness, left atrium and aortic root diameters were significantly higher in group II compared with group I (mean +/- SD 108.5 +/- 19.5 versus 99.7 +/- 19.6 g/m, P < 0.05; 9.3 +/- 0.9 versus 9.1 +/- 0.9 mm, P < 0.05; 33.6 +/- 3.6 versus 32.2 +/- 3.7 mm, P < 0.01; 36.9 +/- 4.6 mm versus 35.5 +/- 4.6, P < 0.05, respectively). The smaller differences seen between groups II and III and between groups I and III were not statistically significant. The prevalence of left ventricular hypertrophy (defined as a left ventricular mass index > 134 g/m in men and > 110 g/m in women) was greater in group II (19%) than in group I (6%) (P < 0.05), whereas the differences between groups II and III and between groups I and III did not reach statistical significance. Differences among the three groups in the prevalence of carotid structural alterations (such as carotid plaques or intima-media thickening) were not statistically significant, and microalbuminuria had a similar prevalence in all three groups.

CONCLUSIONS

Despite similar clinic and 48-h BP values, never-treated hypertensive patients with a persistent non-dipper pattern showed a significantly greater extent of cardiac structural alterations compared with subjects with a reproducible dipping pattern, but not those with a variable BP nocturnal profile. A non-dipping pattern diagnosed on two concordant ABPM periods instead of a single monitoring therefore represents a clinical trait associated with more pronounced cardiac abnormalities. Finally, in non-dipping middle-aged hypertensives, echocardiography appears to provide a more accurate risk stratification than carotid ultrasonography or microalbuminuria.

Reduced nocturnal fall in blood pressure, assessed by two ambulatory blood pressure monitorings and cardiac alterations in early phases of untreated essential hypertension

To investigate whether in recently diagnosed essential hypertensives a reduced nocturnal fall in blood pressure (BP), established on the basis of two 24-h ambulatory blood pressure monitorings (ABPM) is related to a greater cardiovascular damage. In all, 355 consecutive, recently diagnosed, never-treated essential hypertensives referred for the first time to our outpatient clinic were included in the study. Each patient underwent the following procedures: (1) two 24-h ABPMs performed within 3 weeks, (2) 24-h urinary collection for microalbuminuria, (3) nonmydriatic photography of ocular fundi, (4) echocardiography, (5) carotid ultrasonography. We defined nondipping profile as a night-day systolic and diastolic fall < or =10 % (mean of two ABPMs). A dipper BP profile was found in 238 patients, whereas in 117 patients a nondipper profile was present. The two groups were similar for age, gender, body mass index, smoking habit, clinic BP, 48-h BP and heart rate, while, by definition, night-time systolic and diastolic BP were significantly higher in nondippers than in dippers (130/81 vs 121/74 mmHg, P < 0.0001).The prevalence of left ventricular hypertrophy (LVH) defined by four different criteria: (a) LV mass index (LVMI) > or = 125 g/m(2) in both genders; (b) LVMI > or = 134 gm(2) in men and > or = 110 in women; (c) LVMI> or = 125 g/m(2) in men and > or = 110 g/m(2) in women; (d) LVMI > or = 51 g/m(2.7) in men and > or = 47 g/m(2.7) in women was significantly higher in nondippers than in dippers (a: 12 vs 7%, P < 0.05; b: 16 vs 7%, P < 0.01; c: 20 vs 11%, P < 0.01; d: 35 vs 23% P < 0.02) and this finding was associated with a significant increase in aortic root and left atrium dimensions. There were no differences between the two groups in the prevalence of carotid and retinal changes and microalbuminuria. In conclusion our findings suggest that never-treated hypertensives with a reduced BP fall in the night time, defined on the basis of two ABPMs, have a higher prevalence of TOD than dippers, in terms of echocardiographic LVH. In this population setting, cardiac structural alterations are a more sensitive marker of the impact of the nocturnal BP load on cardiovascular system than other extracardiac signs of TOD.

Non-dipper treated hypertensive patients do not have increased cardiac structural alterations

BACKGROUND

Non-dipping pattern in hypertensive patients has been shown to be associated with an excess of target organ damage and with an adverse outcome. The aim of our study was to assess whether a reduced nocturnal fall in blood pressure (BP), established on the basis of a single 24-h BP monitoring, in treated essential hypertensives is related to more prominent cardiac alterations.

METHODS

We enrolled 229 treated hypertensive patients attending the out-patient clinic of our hypertension centre; each patient was subjected to the following procedures : 1) clinic BP measurement; 2) blood and urine sampling for routine blood chemistry and urine examination; 3) standard 12-lead electrocardiogram; 4) echocardiography; 5) ambulatory BP monitoring (ABPM). For the purpose of this study ABPM was carried-out in three subgroups with different clinic BP profile: 1) patients with satisfactory BP control (BP < 140/90 mmHg; group I, n = 58); 2) patients with uncontrolled clinic BP (clinic BP values > or = 140 and/or 90 mmHg) but lower self-measured BP (< 20 mmHg for systolic BP and/or 10 mmHg for diastolic BP; group II, n = 72); 3) patients with refractory hypertension, selected according to WHO/ISH guidelines definition (group III, n = 99). Left ventricular hypertrophy (LVH) was defined by two gender-specific criteria (LV mass index > or = 125/m2 in men and 110 g/m2 in women, > or = 51/gm2.7 in men and 47/g/m2.7 in women).

RESULTS

Of the 229 study participants 119 (51.9%) showed a fall in SBP/DBP < 10% during the night (non-dippers). The prevalence of non-dippers was significantly lower in group I (44.8%) and II (41.6%) than in group III (63.9%, p < 0.01 III vs II and I). The prevalence of LVH varied from 10.3 to 24.1% in group I, 31.9 to 43.1% in group II and from 60.6 to 67.7% in group III (p < 0.01, III vs II and I). No differences in cardiac structure, analysed as continuous variable as well as prevalence of LVH, were found in relationship to dipping or non-dipping status in the three groups.

CONCLUSIONS

In treated essential hypertensives with or without BP control the extent of nocturnal BP decrease is not associated with an increase in LV mass or LVH prevalence; therefore, the non-dipping profile, diagnosed on the basis of a single ABPM, does not identify hypertensive patients with greater cardiac damage.