Ambulatory blood pressure monitoring use in hypertension research and clinical practice

Blood Pressure/Heart Rate-Derived Ratios as Indices of Health and Cardiovascular Pathology

This communication, based on a review of the relevant literature on ratios deriving from blood pressure and heart rate measurements, and their conformance/nonconformance to the mathematical golden rule (ie, 1.681), proposes that such ratios, particularly emanating from large numbers of home blood pressure and heart rate measurements obtained by the patients themselves or their caretakers, may constitute new risk markers, useful in the assessment of health and cardiovascular pathologies, prognosis of morbidity and mortality, and implementation to clinical practice and research.

Effects of long-term indoor air purification intervention on cardiovascular health in elderly: a parallel, double-blinded randomized controlled trial in Hong Kong

Ambient fine particulate matter (PM2.5) is a leading environmental risk factor globally, and over half of the associated disease burden are caused by cardiovascular disease. Numerous randomized controlled trials (RCT) have investigated the short-term cardiovascular benefits of indoor air purifiers (IAPs), but major knowledge gaps remain on their longer-term benefits. In this 1-year, randomized, double-blinded, parallel controlled trial of 47 elderly (ntrue-purification = 24; nsham-purification = 23) aged ≥70 years, true-purification reduced household PM2.5 levels by 28% and maintained lower exposure throughout the year compared to the sham-purification group. After 12 months of intervention, a significant reduction of diastolic blood pressure was found in the true-purification versus sham-purification group (-4.62 [95% CI: -7.28, -1.96] mmHg) compared to baseline measurement prior to the intervention, whereas systolic blood pressure showed directionally consistent but statistically non-significant effect (-2.49 [95% CI: -9.25, 4.28] mmHg). Qualitatively similar patterns of associations were observed for pulse pressure (-2.30 [95% CI: -6.57, 1.96] mmHg) and carotid intima-media thickness (-10.0% [95% CI: -24.8%, 4.7%]), but these were not statistically significant. Overall, we found suggestive evidence of cardiovascular benefits of long-term IAPs use, particularly on diastolic blood pressure. Evidence on other longer-term cardiovascular traits is less clear. Further trials with larger sample sizes and long-term follow-up are needed across diverse populations to evaluate the cardiovascular benefits of IAPs.

The relationship of left ventricular outflow tract presystolic wave and 24-h ambulatory blood pressure measurements

OBJECTIVE

Left ventricular outflow tract (LVOT) presystolic wave is a novel marker for several cardiac conditions. It is shown to be related to several cardiac conditions. The aim of this study is to investigate the relationship between LVOT presystolic wave and 24-h ambulatory blood pressure measurements.

METHODS

A total of 194 patients who came to the cardiology outpatient clinic were prospectively enrolled in the study. After demographic and clinical inquiry, blood biochemistry and hemogram tests were performed. Each patient was evaluated with echocardiography and 24-h ambulatory blood pressure measurement. The patients were divided into hypertensive and nonhypertensive groups regarding their ambulatory blood pressure measurements and the LVOT presystolic wave of the groups on echocardiography was compared.

RESULTS

The hypertensive group was significantly older (59.34 ± 11.15 vs. 49.89 ± 15.43; P  < 0.001). Presystolic wave presence (96.2 vs. 29.5%; P  < 0.001) and velocity (62.23 vs. 29.42; P  < 0.001) were higher in patients with hypertension. Blood pressure values and LVOT amplitudes showed a positive correlation ( P  < 0.001; r  = 0.326). In multivariable logistic regression analysis; age, BMI and the presystolic wave were independently associated with hypertension (odds ratio: 8.09; P  < 0.001).

CONCLUSION

LVOT presystolic wave is associated with systemic hypertension and it could be used as a predictor for systemic hypertensive patients.

Autonomic nervous system function in women with anorexia nervosa

PURPOSE

Abnormalities in autonomic function have been observed in people with anorexia nervosa. However, the majority of investigations have utilised heart rate variability as the sole assessment of autonomic activity. The current study utilised a variety of methodologies to assess autonomic nervous system function in women with a current diagnosis of anorexia, a past diagnosis of anorexia who were weight-restored, and healthy controls.

METHODS

The sample included 37 participants: 10 participants with anorexia, 17 weight-restored participants (minimum body mass index > 18.5 for minimum of 12 months) and 10 controls. Assessments of autonomic function included muscle sympathetic nerve activity (MSNA) using microneurography, heart rate variability, baroreflex sensitivity, blood pressure variability, head-up tilt table test, sudomotor function and assessment of plasma catecholamines.

RESULTS

MSNA (bursts/min) was significantly decreased in both anorexia (10.22 ± 6.24) and weight-restored (17.58 ± 1.68) groups, as compared to controls (23.62 ± 1.01, p < 0.001 and p = 0.033, respectively). Participants with anorexia had a significantly lower standard deviation in heart rate, lower blood pressure variability and decreased sudomotor function as compared to controls. Weight-restored participants demonstrated decreased baroreflex sensitivity in response to head-up tilt as compared to controls.

CONCLUSION

Women with a current or previous diagnosis of anorexia have significantly decreased sympathetic activity, which may reflect a physiological response to decreased energy intake. During the state of starvation, women with anorexia also displayed decreased sudomotor function. The consequences of a sustained decrease in MSNA are unknown, and future studies should investigate autonomic function in long-term weight-restored participants to determine whether activity returns to normal.

Early onset neurocirculatory response to static handgrip is associated with greater blood pressure variability in women with posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a psychiatric illness that is more prevalent in women, and accumulating evidence suggests a link between PTSD and future development of cardiovascular disease. The underlying mechanisms are unclear, but augmented sympathetic reactivity to daily stressors may be involved. We measured muscle sympathetic nerve activity (MSNA), blood pressure (BP), and heart rate responses in 14 women with PTSD and 14 healthy women (controls) during static handgrip (SHG) exercise to fatigue at 40% of maximal voluntary contraction (MVC). Two minutes of postexercise circulatory arrest (PECA) was followed immediately after SHG to fatigue. MVC and the time to fatigue during SHG did not differ between groups (both P > 0.05). At the first 30 s of SHG, women with PTSD showed augmented sympathetic neural [mean ± SD, ∆MSNA burst frequency (BF): 5 ± 4 vs. 2 ± 3 bursts/30 s, P = 0.02 and ∆MSNA total activity (TA): 82 ± 58 vs. 25 ± 38 arbitrary units/30 s, P = 0.004] and pressor (∆systolic BP: 10 ± 5 vs. 4 ± 3 mmHg, P = 0.003) responses compared with controls. However, MSNA and BP responses at fatigue and during PECA were not different between groups. More interestingly, the augmented initial neural and pressor responses to SHG were associated with greater awake systolic BP variability during ambulation in women with PTSD (MSNA BF: r = 0.55, MSNA TA: r = 0.62, and SBP: r = 0.69, all P < 0.05). These results suggest that early onset exercise pressor response in women with PTSD may be attributed to enhanced mechano- rather than metaboreflexes, which might contribute to the mechanisms underlying the link between PTSD and cardiovascular risk.NEW & NOTEWORTHY The novel findings of the current study are that women with posttraumatic stress disorder (PTSD) exhibited augmented sympathetic neural and pressor responses at the first 30 s of submaximal isometric muscle contraction. More interestingly, exaggerated neurocirculatory responses at the onset of muscle contraction were associated with greater ambulatory awake systolic blood pressure fluctuations in women with PTSD. Our findings expand the knowledge on the physiological mechanisms that perhaps contribute to increased risk of cardiovascular disease in such a population.

Heritability of blood pressure traits in diverse populations: a systematic review and meta-analysis

To understand the genetic architecture and make inferences about transmissible resemblance of systolic and diastolic blood pressure (SBP and DBP) traits in relatives, the polygenic effect of individual alleles in terms of narrow heritability (h²) is usually assessed. The heritability estimates for BP traits are population specific parameters with a wide range in different studies (6-68%), and there is no comprehensive evidence comparing its source(s) of heterogeneity. To fill the gap, this systematic review and meta-analysis study was carried out. Using MeSH terms, 647 records were detected through searching, "Pubmed," "Ebsco," "Web of Science," and "Scopus" databases. From these, 24 relevant full-text articles with 47 comparisons for final quantitative meta-analysis were included in our review over the five continents. The additive genetic effects of both traits showed a widespread distribution (h²_SBP: 17-52%, h²_DBP:19-41%). Different categories of transmissible resemblance for BP traits were explained by ethnicity; higher heritability was estimated in Europeans and Mexican Americans, while lower heritability was seen in the Middle Eastern, Asians, Africans, Latinos, Hispanics, and American Indians. Low heterogeneity of polygenic effects was seen for both traits in subgroups of the Middle East, Asians, Africans, and Latinos, Hispanics, American Indians. However, there was a substantial heterogeneity of h² within European and Mexican American studies. Neither pedigree type nor other covariates explained the variance of additive genetic effects of BP traits in different ethnicities.

Understanding short-term blood-pressure-variability phenotypes: from concept to clinical practice

Clinic blood pressure (BP) is recognized as the gold standard for the screening, diagnosis, and management of hypertension. However, optimal diagnosis and successful management of hypertension cannot be achieved exclusively by a handful of conventionally acquired BP readings. It is critical to estimate the magnitude of BP variability by estimating and quantifying each individual patient's specific BP variations. Short-term BP variability or exaggerated circadian BP variations that occur within a day are associated with increased cardiovascular events, mortality and target-organ damage. Popular concepts of BP variability, including "white-coat hypertension" and "masked hypertension", are well recognized in clinical practice. However, nocturnal hypertension, morning surge, and morning hypertension are also important phenotypes of short-term BP variability that warrant attention, especially in the primary-care setting. In this review, we try to theorize and explain these phenotypes to ensure they are better understood and recognized in day-to-day clinical practice.

Excessive Erythrocytosis and Cardiovascular Risk in Andean Highlanders

Corante, Noemí, Cecilia Anza-Ramírez, Rómulo Figueroa-Mujíca, José Luis Macarlupú, Gustavo Vizcardo-Galindo, Grzegorz Bilo, Gianfranco Parati, Jorge L. Gamboa, Fabiola León-Velarde, and Francisco C. Villafuerte. Excessive erythrocytosis and cardiovascular risk in Andean highlanders. High Alt Med Biol. 19:221–231, 2018.—Cardiovascular diseases are the main cause of death worldwide. Life under high-altitude (HA) hypoxic conditions is believed to provide highlanders with a natural protection against cardiovascular and metabolic diseases compared with sea-level inhabitants. However, some HA dwellers become intolerant to chronic hypoxia and develop a progressive incapacitating syndrome known as chronic mountain sickness (CMS), characterized by excessive erythrocytosis (EE; Hb ≥21 g/dL in men, Hb ≥19 g/dL in women). Evidence from HA studies suggests that, in addition to CMS typical signs and symptoms, these highlanders may also suffer from metabolic and cardiovascular disorders. Thus, we hypothesize that this syndrome is also associated to the loss of the cardiometabolic protection observed in healthy highlanders (HH), and therefore to a higher cardiovascular risk (CVR). The aim of the present work was to evaluate the association between EE and CVR calculated using the Framingham General CVR Score and between EE and CVR factors in male highlanders. This cross-sectional study included 342 males from Cerro de Pasco, Peru at 4340 m (HH = 209, CMS = 133). Associations were assessed by multiple logistic regressions adjusted for potential confounders (BMI, pulse oxygen saturation and age). The adjusted models show that the odds of high CVR (>20%) in highlanders with EE was 3.63 times the odds in HH (CI 95%:1.22–10.78; p = 0.020), and that EE is associated to hypertension, elevated fasting serum glucose, insulin resistance, and elevated fasting serum triglycerides. Our results suggest that individuals who suffer from EE are at increased risk of developing cardiovascular events compared with their healthy counterparts.

Cost-effectiveness of ambulatory blood pressure monitoring in the management of hypertension

INTRODUCTION AND OBJECTIVES

The prevalence of hypertension in Portugal is between 29.1% and 42.2%. International studies show that 13% of individuals have masked hypertension and 13% of diagnoses based on office blood pressure measurements are in fact white coat hypertension. More sensitive and specific blood pressure measuring methods could avoid costs associated with misdiagnosis. The aim of this study was to review the cost-effectiveness of ambulatory blood pressure monitoring (ABPM) compared to other methods in the management of hypertension.

METHODS

We performed a literature search in CMA Infobase, Guidelines Finder, National Guideline Clearinghouse, Bandolier, BMJ Clinical Evidence, the Cochrane Library, DARE, Medline, the Trip Database, SUMSearch and Índex das Revistas Médicas Portuguesas. We researched articles published between January 2005 and August 2015 in Portuguese, English and Spanish, using the MeSH terms "Hypertension", "Blood Pressure Monitoring, Ambulatory" and "Cost-Benefit Analysis" and the Portuguese search terms "Hipertensão", "Monitorização Ambulatorial da Pressão Arterial" and "Análise Custo-Benefício". Levels of evidence and grades of recommendation were attributed according to the Oxford Centre for Evidence-Based Medicine scale.

RESULTS

Five hundred and twenty-five articles were identified. We included five original studies and one clinical practice guideline. All of them state that ABPM is the most cost-effective method. Two report better blood pressure control, and a Portuguese study revealed a saving of 23%.

CONCLUSIONS

The evidence shows that ABPM is cost-effective, avoiding iatrogenic effects and reducing expenditure on treatment (grade of recommendation B). The included studies provide a solid basis, but further evidence of reproducibility is needed in research that is not based mainly on analytical models.

Impact of baseline systolic blood pressure on visit-to-visit blood pressure variability: the Kailuan study

Background

To investigate the relationship between baseline systolic blood pressure (SBP) and visit-to-visit blood pressure variability in a general population.

Methods

This is a prospective longitudinal cohort study on cardiovascular risk factors and cardiovascular or cerebrovascular events. Study participants attended a face-to-face interview every 2 years. Blood pressure variability was defined using the standard deviation and coefficient of variation of all SBP values at baseline and follow-up visits. The coefficient of variation is the ratio of the standard deviation to the mean SBP. We used multivariate linear regression models to test the relationships between SBP and standard deviation, and between SBP and coefficient of variation.

Results

Approximately 43,360 participants (mean age: 48.2±11.5 years) were selected. In multivariate analysis, after adjustment for potential confounders, baseline SBPs <120 mmHg were inversely related to standard deviation (P<0.001) and coefficient of variation (P<0.001). In contrast, baseline SBPs ≥140 mmHg were significantly positively associated with standard deviation (P<0.001) and coefficient of variation (P<0.001). Baseline SBPs of 120–140 mmHg were associated with the lowest standard deviation and coefficient of variation. The associations between baseline SBP and standard deviation, and between SBP and coefficient of variation during follow-ups showed a U curve.

Conclusion

Both lower and higher baseline SBPs were associated with increased blood pressure variability. To control blood pressure variability, a good target SBP range for a general population might be 120–139 mmHg.

Blood pressure variability: assessment, predictive value, and potential as a therapeutic target

A large body of evidence has consistently supported the relationship between blood pressure (BP) levels and the risk of cardiovascular complications. In recent years, several independent studies have also indicated that this risk may not only depend on the magnitude of the blood pressure elevation per se but also on the presence of other associated conditions such as increased blood pressure variability. This concept has been supported by a series of reports, most of which post hoc analyses of clinical trials in hypertension, showing that increasing values of BP variability (BPV) (either in the short term, in the midterm, or in the long term) may predict development, progression, and severity of cardiac, vascular, and renal organ damage, as well as cardiovascular events and mortality. Remarkably, studies conducted in populations at high cardiovascular risk have shown increasing values of BPV in the individual subjects (so-called intra- or within-individual BPV) to be strong predictors of cardiovascular morbidity and mortality, even to a larger extent than average BP values. However, in subjects at low to moderate cardiovascular risk, the contribution of BPV to cardiovascular risk prediction over and beyond average BP values has been shown to be only moderate. The aim of this paper is to critically review the evidence addressing the prognostic relevance of different components of BPV addressing a yet open question, i.e., whether routine assessment of BPV in clinical practice should be regarded as an additional target of antihypertensive treatment to improve cardiovascular protection.

Differences in mean arterial pressure of young and elderly people measured by oscilometry during inflation and deflation of the arm cuff

Systemic arterial blood pressure (BP) is one of the most important parameters of the cardiovascular system. An oscillometric NIBP monitor was specifically designed to measure oscillometric pulsations and mean arterial pressure (MAP) during inflation and deflation of the cuff. Nineteen healthy young (age 23.1±1.7 years; mean±SD) and 35 elderly (83.9±7.9 years; mean±SD) subjects were studied. Differential analysis of MAP during inflation and deflation show mean |ΔMAP|=2.9±2.6 mm Hg in the young group (mean±SD) and |ΔMAP|=6.3±5.2 mm Hg for seniors (mean±SD). There was a significant difference (p<0.05) in means of |ΔMAP| measured during cuff inflation and cuff deflation between both groups. In about 50% of elderly subjects |ΔMAP| was higher than 5 mm Hg. Potential clinical relevance of the method needs to be further evaluated.

Association of Serum Uric Acid Level With Blood Pressure Variability in Newly Diagnosed Essential Hypertension

Serum uric acid (UA) is independently associated with hypertension and blood pressure (BP) variability (BPV) is associated with cardiovascular events and mortality in hypertensive patients. The aim of the present study was to assess the association of serum UA with BPV in 300 untreated essential hypertension patients (mean age 57.3±13.6 years). BPV was quantified as the standard deviation (SD) of the 24-hour, daytime, and nighttime mean values obtained by using ambulatory BP monitoring. In correlation analysis, log UA values were found to be positively correlated with 24-hour systolic BPV and nighttime systolic and diastolic BPV (Pearson coefficients of 0.246, 0.280, and 0.353, respectively; P<.001 for all). In multivariate analysis, log UA had an independent association with 24-hour systolic BPV and nighttime systolic and diastolic BPV. This study show for the first time that increased serum UA is independently associated with BPV in untreated essential hypertension patients.

Relationship of short-term blood pressure variability with carotid intima-media thickness in hypertensive patients

Background

High blood pressure (BP) is among significant risk factor for stroke and other vascular occurrences, it experiences nonstop fluctuations over time as a result of a complex interface among cardiovascular control mechanisms. Large blood pressure variability (BPV) has been proved to be promising in providing potential regulatory mechanisms of the cardiovascular system. Although the previous studies also showed that BPV is associated with increased carotid intima-media thickness (IMT) and plaque, whether the correlation between variability in blood pressure and left common carotid artery-intima-media thickness (LCCA-IMT) is stronger than right common carotid artery-intima-media thickness (RCCA-IMT) remains uncertain in hypertension.

Methods

We conduct a study (78 hypertensive subjects, aged 28–79) to evaluate the relationship between BPV and carotid intima-media thickness in Shenzhen. The blood pressure was collected using the 24 h ambulatory blood pressure monitoring, and its variability was evaluated using standard deviation (SD), coefficient of variation (CV), and average real variability (ARV) during 24 h, daytime and nighttime. All the IMT measurements are collected by ultrasound.

Results

As the results showed, 24 h systolic blood pressure variability (SBPV) evaluated by SD and ARV were significantly related to LCCA-IMT (r¹ = 0.261, P = 0.021; r¹ = 0.262, P = 0.021, resp.). For the daytime diastolic blood pressure variability (DBPV), ARV indices were significantly related to LCCA-IMT (r¹ = 0.239, P = 0.035), which differed form BPV evaluated by SD and CV. For the night time, there is no significant correlation between the BPV and IMT. Moreover, for all the subjects, there is no significant correlation between the BPV and RCCA-IMT/number of plaques, whereas, the SD, CV, and ARV of daytime SBP showed a positive correlation with LCCA-IMT (r¹ = 0.312, P = 0.005; r¹ = 0.255, P = 0.024; r¹ = 0.284, P = 0.012, resp.). Moreover, the ARV of daytime SBPV, 24 h SBPV and nighttime DBPV showed a positive correlation with the number of plaques of LCCA (r¹ = 0.356, P = 0.008; r¹ = 0.297, P = 0.027; r¹ = 0.278, P = 0.040, resp.). In addition, the number of plaques in LCCA had higher correlation with pulse pressure and diastolic blood pressure than that in RCCA. And multiple regression analysis indicated LCCA-IMT might not only be influenced by age or smoking but also by the SD index of daytime SBPV (p = 0.035).

Conclusions

The results show that SBPV during daytime and 24 h had significant correlation with IMT, for the hypertensive subjects from the southern area of China. Moreover, we also found the daytime SBPV to be the best predictor for the progression of IMT in multivariate regression analysis. In addition, the present study suggests that the correlation between BPV and left common carotid artery—intima-media thickness/number of plaques is stronger than right common carotid artery-intima-media thickness/number of plaques.

Heart rate and blood pressure variability in children with chronic kidney disease: a report from the CKiD study

BACKGROUND

Autonomic nervous system dysfunction and sympathetic nervous system over-activity play important roles in the development of hypertension associated with chronic kidney disease (CKD). In adults, increased blood pressure variability (BPV) appears to be directly related to sympathetic over-activity with increased risk of end-organ damage and cardiovascular events. Decreased heart rate variability (HRV) has been observed in adults with CKD, and is an independent predictor of mortality.

METHODS

The purpose of this study was to evaluate BPV and HRV in pediatric patients enrolled in the Chronic Kidney Disease in Children Study. Ambulatory blood pressure monitoring data were available for analysis of 215 person-visits from 144 children that were not receiving antihypertensive medications.

RESULTS

BPV and HRV were determined by standard deviation and coefficient of variation for heart rate and systolic and diastolic blood pressure for each patient averaged for wake/sleep periods during 24-h monitoring. Uniformly lower values were displayed during sleep versus wake periods: BPV was 20 % lower during sleep (p < 0.001) and HRV was 30 % lower during sleep (p < 0.001). A significant increase in systolic BPV was observed in hypertensive children compared to children with normal blood pressure (6.9 %, p = 0.009). Increased diastolic BPV was detected among hypertensive children during sleep period compared to children with normal blood pressure (11.5 %, p = 0.008). There was a significant decrease in HRV in hypertensive compared to normotensive children (-8.2 %, p = 0.006).

CONCLUSIONS

These findings are similar to those in adult patients and may underscore childhood origin and natural progression of adverse cardiovascular outcomes in adults with CKD.

Assessment and interpretation of blood pressure variability in a clinical setting

Blood pressure (BP) is characterized by marked fluctuations occurring within the 24 h as a result of complex interactions between behavioral, environmental, humoral, and neural central or reflex influences. Significant BP variations also occur over more prolonged periods of time (i.e. between days, weeks, months, seasons and even years), not as a random phenomenon but as a result of several interacting factors yet not completely identified. Depending on the method and time interval considered for measurement, the clinical significance and prognostic implications of different types of BP variability (BPV) may substantially differ. Either in the short or in the long term, BPV has been associated with development, progression and severity of cardiac, vascular and renal organ damage and with an increased risk of cardiovascular events and mortality, independently adding to cardiovascular risk, over and above the contribution of elevated mean BP levels. The present paper provides a review on the main methods currently employed for assessment of BPV as well as on the mechanisms, clinical interpretation and prognostic significance of different types of BPV, addressing the question on whether BPV should be a target for antihypertensive treatment for the current prevention of cardiovascular disease.

Environmental and genetic contribution to hypertension prevalence: data from an epidemiological survey on Sardinian genetic isolates

Background and Objectives

Hypertension represents a major cause of cardiovascular morbidity and mortality worldwide but its prevalence has been shown to vary in different countries. The reasons for such differences are still matter of debate, the relative contributions given by environmental and genetic factors being still poorly defined. We estimated the current prevalence, distribution and determinants of hypertension in isolated Sardinian populations and also investigated the environmental and genetic contribution to hypertension prevalence taking advantage of the characteristics of such populations.

Methods and Results

An epidemiological survey with cross-sectional design was carried out measuring blood pressure in 9845 inhabitants of 10 villages of Ogliastra region between 2002 and 2008. Regression analysis for assessing blood pressure determinants and variance component models for estimating heritability were performed. Overall 38.8% of this population had hypertension, its prevalence varying significantly by age, sex and among villages taking into account age and sex structure of their population. About 50% of hypertensives had prior cardiovascular disease. High blood pressure was independently associated with age, obesity related factors, heart rate, total cholesterol, alcohol consumption, low education and smoking status, all these factors contributing more in women than in men. Heritability was 27% for diastolic and 36% for systolic blood pressure, its contribution being significantly higher in men (57%) than in women (46%). Finally, the genetic correlation between systolic and diastolic blood pressure was 0.74, indicating incomplete pleiotropy.

Conclusion

Genetic factors involved in the expression of blood pressure traits account for about 30% of the phenotypic variance, but seem to play a larger role in men; comorbidities and environmental factors remain of predominant importance, but seem to contribute much more in women.

Assessment and management of blood-pressure variability

Blood pressure (BP) is characterized by marked short-term fluctuations occurring within a 24 h period (beat-to-beat, minute-to-minute, hour-to-hour, and day-to-night changes) and also by long-term fluctuations occurring over more-prolonged periods of time (days, weeks, months, seasons, and even years). Rather than representing 'background noise' or a randomly occurring phenomenon, these variations have been shown to be the result of complex interactions between extrinsic environmental and behavioural factors and intrinsic cardiovascular regulatory mechanisms. Although the adverse cardiovascular consequences of hypertension largely depend on absolute BP values, evidence from observational studies and post-hoc analyses of data from clinical trials have indicated that these outcomes might also depend on increased BP variability (BPV). Increased short-term and long-term BPV are associated with the development, progression, and severity of cardiac, vascular, and renal damage and with an increased risk of cardiovascular events and mortality. Of particular interest are the findings from post-hoc analyses of large intervention trials in hypertension, showing that within-patient visit-to-visit BPV is strongly prognostic for cardiovascular morbidity and mortality. This result has prompted discussion on whether antihypertensive treatment should be targeted not only towards reducing mean BP levels but also to stabilizing BPV with the aim of achieving consistent BP control over time, which might favour cardiovascular protection.

Blood pressure variability, cardiovascular risk, and risk for renal disease progression

The adverse cardiovascular consequences of high blood pressure (BP) not only depend on absolute BP values, but also on BP variability (BPV). Evidence has been provided that independently of mean BP levels, BP variations in the short- and long-term are associated with the development, progression and severity of cardiac, vascular and renal organ damage, and with an increased risk of CV events and mortality. Alterations in BPV have also been shown to be predictive of the development and progression of renal damage, which is of relevance if considering that impaired renal function in a hypertensive patient constitutes a very potent predictor of future CV events and mortality even in treated subjects. This review will address whether antihypertensive treatment should target alterations in BPV, in addition to reducing absolute BP levels, in order to achieve the highest CV and renal protection in hypertensive and renal patients.

Baroreflex modulation during sleep and in obstructive sleep apnea syndrome

This review focuses on the complex integration between cardiovascular reflexes and central autonomic influences controlling physiological sleep-dependent changes in arterial blood pressure and heart rate. A brief introduction on the anatomic and functional organization of the arterial baroreflex and the methods available to assess its function in humans is followed by an analysis of the functional interaction between autonomic nervous system and sleep mechanisms at the highest levels of brain organization. An insight into these interactions is important to shed light on the physiopathology of the most frequent complications of obstructive sleep apnea syndrome, such as sustained arterial hypertension, and excessive daytime sleepiness.

Diagnosis and management of patients with white-coat and masked hypertension

White-coat hypertension is characterized by an elevation in clinic blood pressure but normal home or ambulatory blood-pressure values, whereas patients with masked hypertension have normal clinic blood pressure and elevated ambulatory or home blood-pressure load. Both white-coat and masked hypertension are frequent clinical entities that need appropriate recognition and a close diagnostic follow-up. White-coat and masked hypertension seem to be associated with organ damage and increased cardiovascular risk, although not invariably. In addition, patients with masked or white-coat hypertension have an increased risk of abnormalities affecting their glucose and lipid profiles. Therefore, the diagnosis of these conditions should be accurate and include the assessment of cardiovascular as well as of metabolic risk. Once diagnosed, first-line therapeutic interventions should be nonpharmacological and aim at lifestyle changes, but drug treatment can be indicated, particularly when the patient's cardiovascular risk profile is elevated or when target-organ damage is detected.

Optimal schedule for home blood pressure measurement based on prognostic data: the Finn-Home Study

Current guidelines based on cross-sectional statistical parameters derived from reference populations make equivocal recommendations for the optimal schedule of home blood pressure (BP) measurement. The objective of this study was to determine a schedule for home BP measurements in relation to their predictive value for total cardiovascular risk. Home BP was measured twice every morning and evening for 1 week in an unselected nationwide population of 2081 subjects aged 45 to 74 years. The prognostic significance of BP for fatal and nonfatal cardiovascular events was examined using adjusted Cox proportional hazards regression models. A total of 162 cardiovascular events were recorded during a 6.8-year follow-up. The predictive value of home BP increased progressively with the number of measurements, showing the highest predictive value with the average of all measurements (systolic/diastolic hazard ratio per 1-mm Hg increase in BP: 1.021/1.034; systolic/ diastolic 95% CI: 1.012 to 1.030/1.018 to 1.049). However, most of this increase was achieved during the first 3 days of measurement (hazard ratio: 1.017/1.028; 95% CI: 1.009 to 1.026/1.013 to 1.045), and only minimal increase occurred after day 6. No additional benefit was achieved by discarding the values obtained during the first day of measurement. Morning and evening BPs were equally predictive of future cardiovascular events. Novel prognostic data from this study show that measurement of home BP twice in the morning and evening, preferably for a period of 7 days, or for at least 3 days, provides a thorough image of a patient's BP level. This information should be used to prepare a unified international guideline for home BP measurement.

Evaluating 24-h antihypertensive efficacy by the smoothness index: a meta-analysis of an ambulatory blood pressure monitoring database

OBJECTIVE

The aim of this meta-analysis was to compare the 24-h antihypertensive efficacy of different treatments using the smoothness index.

METHODS

Data were taken from the telmisartan ambulatory blood pressure monitoring (ABPM) clinical programme. Eleven clinical trials that randomized mild-to-moderate hypertensive patients to treatment with telmisartan 40/80 mg, losartan 50 mg, valsartan 80/160 mg, ramipril 10 mg, amlodipine 5 mg monotherapy, or with an angiotensin receptor blocker (ARB) and hydrochlorothiazide (HCTZ) 12.5/25 mg, were included. Treatment duration ranged from 4 to 14 weeks. The smoothness index was calculated according to the published formula.

RESULTS

Altogether, 5188 patients were included (65% men; 52% were using telmisartan as monotherapy or in combination with HCTZ). Telmisartan 80 mg had a higher smoothness index than losartan, valsartan or ramipril (P < 0.05), and was comparable with amlodipine. All combination therapies had a higher smoothness index than monotherapy; the largest value was observed with telmisartan 80 mg and HCTZ 12.5 mg. Overall, the smoothness index was lower in men, older patients, black patients, smokers and in those with lower baseline blood pressure (P < 0.05).

CONCLUSION

The smoothness index was affected by age, race, sex, behavioural and haemodynamic factors. It was also able to differentiate the 24-h blood pressure effects of antihypertensive drugs, with telmisartan and amlodipine achieving the highest values, possibly because of their long plasma half-lives. All combination therapies had a higher smoothness index than monotherapy. An understanding of the relative effects of different antihypertensives on the smoothness index may help to differentiate their effectiveness in reducing blood pressure-related cardiovascular risk.

Efficacy and tolerability of olmesartan/amlodipine combination therapy in patients with mild-to-severe hypertension: focus on 24-h blood pressure control

European guidelines recommend that treating patients with hypertension to blood pressure (BP) goal is an important target for cardiovascular (CV) risk reduction. However, office BP may be a suboptimal target, given its limitations. Indeed, there is evidence that 24-h ambulatory BP monitoring (ABPM) parameters may score better in this regard, representing more accurate predictors of CV risk. In particular, mean 24-h BP and BP variability both correlate closely with hypertension end-organ damage and rate of CV events, which suggests that antihypertensive therapy should provide smooth BP control over the full 24-h dosing interval. The use of ABPM has demonstrated that fixed-dose combination therapy, comprising agents with complementary mechanisms of action, may overcome the challenge of suboptimal BP control by providing improvements in antihypertensive efficacy and tolerability throughout the 24-h period. Olmesartan/amlodipine is one of the latest combination therapies to be approved, and a number of large clinical trials have demonstrated the efficacy and tolerability of this combination in patients with mild-to-severe hypertension. Furthermore, recent ABPM studies of olmesartan/amlodipine-based treatment algorithms have shown the satisfactory 24-h antihypertensive efficacy of this fixed-dose combination. This review provides an overview of recent clinical data on the efficacy and tolerability of fixed-dose olmesartan/amlodipine combination therapy for the treatment of mild-to-severe hypertension, with a focus on sustained 24-h BP control.

Headache: Prevalence and relationship with office or ambulatory blood pressure in a general population sample (the Vobarno Study)

The association of headache and arterial hypertension is still controversial, although headache is usually considered a symptom of hypertension. The aim of this study is to evaluate the prevalence of headache in a general population sample and the relationship with arterial hypertension, as diagnosed by office measurements and ambulatory monitoring of blood pressure (BP).

PATIENTS AND METHODS

In the randomized sample of the Vobarno population, 301 subjects (126 males, 175 females, age range 35-50 years) underwent a structured standardized headache questionnaire, office and 24-h ambulatory BP monitoring.

RESULTS

Prevalence of lifetime headache and of migraine was greater in females than in males. Office and 24-h BP values did not differ between subjects without headache and subjects with headache. No differences in headache prevalence (58% vs 55%), migraine prevalence (32% vs 28%) and use of analgesic drugs in the presence of headache (82% vs 78%) were observed between hypertensive patients (93.5% newly diagnosed, 6.5% treated) and normotensive subjects.

CONCLUSIONS

In a general population sample, hypertension (diagnosed by office and/or 24-h BP) is not associated with headache.

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.

How family history and risk factors for hypertension relate to ambulatory blood pressure in healthy adults

BACKGROUND

Although family history is a major predictor of hypertension, other risk factors have been linked to elevated blood pressure (BP). This study explored the relationship of norepinephrine (NE), insulin resistance and lipids to family history of hypertension, and attempted to determine the combined effects of family history and these factors on BP.

METHODS

A total of 220 healthy men and women, aged 22-50 years, completed two 24 h ambulatory BP sessions. Based on family history information obtained from parents, three groups were formed: subjects with two hypertensive parents, one hypertensive parent or normotensive parents. Plasma samples were obtained to derive fasting catecholamine levels, insulin, glucose and lipids.

RESULTS

Individuals with two hypertensive parents had high insulin, insulin resistance and low-density lipoprotein cholesterol. Although NE was not directly linked to family history, high NE levels were associated with increased BP, after controlling for family history and body mass index. Women with two hypertensive parents and elevated NE levels had higher systolic BP and diastolic BP during waking and sleep periods. In men the combination of two hypertensive parents and high NE was related only to diastolic BP during waking.

CONCLUSIONS

NE results provide evidence of sympathetic activation in the identification of individuals at risk for hypertension. Studying family history of hypertension and other risk factors in healthy individuals provides a unique opportunity to explore factors leading to elevated BP long before a diagnosis of hypertension is made.

Assessment of long-term antihypertensive treatment by clinic and ambulatory blood pressure: data from the European Lacidipine Study on Atherosclerosis

OBJECTIVES

Information on the features of long-term modifications of clinic and 24-h ambulatory blood pressure (ABP) by treatment is limited. The present study aimed to address this issue.

METHODS

Ambulatory BP monitoring and clinic BP (CBP) measurements were performed at baseline and at yearly intervals over a 4-year follow-up period in 1523 hypertensives (56.1 +/- 7.6 years) randomized to treatment with lacidipine or atenolol in the European Lacidipine Study on Atherosclerosis (ELSA).

RESULTS

CBP was always greater than ABP, while reductions in all BP values (greater for CBP than for ABP) were on average maintained throughout 4 years, CBP changes showing limited relationship with ABP changes (r = 0.14-0.27). BP reductions by treatment during daytime and night-time were correlated (r = 0.63-0.73). BP normalization was achieved in a greater percentage of patients for CBP (41.7%) than for ABP (25.3%), with systolic BP control being always less common than diastolic BP control. BP normalization was more frequent at single yearly visits than throughout the 4 years. Twenty-four-hour BP variability was reduced by treatment over 4 years in absolute but not in normalized units.

CONCLUSIONS

The present study provides the best evidence available on long-term effect of antihypertensive treatment on both ABP and CBP. On average, ABP was sustainedly reduced by treatment throughout the follow-up period, but 24-h BP was more difficult to control than CBP. In several patients, ABP control was unstable between visits, the percentage of patients under control over 4 years being much less than that of those controlled at each year. Treatment induced a reduction in absolute but not in normalized BP variability estimates. This has clinical implications because of the prognostic importance of ABP mean values and variability.

Blood pressure variability: its measurement and significance in hypertension

Blood pressure (BP) fluctuations over time physiologically result from the complex interaction between environmental stimulation, genetic factors, and cardiovascular control mechanisms. Ambulatory BP-monitoring techniques, in particular systems providing beat-by-beat BP recording, have allowed a detailed description of the different components contributing to overall BP variability (BPV) over 24 hours, including short-lasting and more sustained BP changes. In hypertension, BPV increases with increasing BP levels, and evidence is available that its magnitude correlates closely with target-organ damage and with the incidence of cardiovascular events, independent of absolute BP levels. It has been suggested that drugs capable of providing smooth 24-hour BP control, reducing BPV, may confer additional target-organ protection. Mathematic indices, such as the trough-to-peak ratio and the smoothness index, represent useful measures of the homogeneity of the antihypertensive effect over 24 hours. Further studies are still needed to confirm that, in humans, interventions that can reduce BPV can also reduce the rate of cardiovascular events.

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.

Statins and blood pressure: is there an effect or not?

In addition to the lipid-lowering effects of statins, several basic and clinical studies in recent years have examined the effects of these agents on other cardiovascular parameters. Some of these studies investigated the general impact of a statin on blood pressure (BP) among various other factors, while others were specifically designed to determine this effect. Data from animal studies are conflicting but the majority of human studies in the field report a beneficial effect, and most available statin compounds are reported to lower BP levels. Recent clinical studies using ambulatory BP measurements support these findings. Although the exact actions of statins involved in this effect are unknown, several possible mechanisms can be hypothesized. This review summarizes existing data on the effect of statins on BP, aiming to give an overview of the current knowledge and to provide perspectives for future research in the field.

Adding hydrochlorothiazide to olmesartan dose dependently improves 24-h blood pressure and response rates in mild-to-moderate hypertension

OBJECTIVE

To test whether adding hydrochlorothiazide (HCTZ) (12.5 or 25 mg) to olmesartan 20 mg improves 24-h blood pressure in patients whose conventional diastolic blood pressure is inadequately controlled by olmesartan monotherapy.

PATIENTS

Male and female patients > or = 18 years with mean sitting diastolic blood pressure (DBP) of 100-115 mmHg, mean sitting systolic blood pressure (SBP) greater than 150 mmHg, mean 24-h DBP of at least 84 mmHg, and at least 30% of DBP daytime readings > 90 mmHg.

INTERVENTIONS

Four weeks of single-blind treatment with olmesartan 20 mg once daily, followed in non-responders by 8 weeks of randomized double-blind treatment with placebo or HCTZ (12.5 or 25 mg) once-daily, added to olmesartan.

RESULTS

HCTZ 25 mg added to olmesartan 20 mg decreased mean daytime DBP significantly more (P = 0.0012) than placebo added to olmesartan 20 mg. Compared to olmesartan monotherapy, mean 24-h DBP and SBP were significantly reduced by combination therapy with olmesartan/HCTZ 20/12.5 mg (-1.9 mmHg, P = 0.0167 and -3.9 mmHg, P = 0.0018, respectively) and 20/25 mg (-3.7 and -7.4 mmHg respectively, P < 0.0001 for both). Mean 24-h DBP and SBP and mean night-time SBP reductions were significantly greater for HCTZ 25 mg than for HCTZ 12.5 mg. Response rates (mean daytime DBP assessed by ambulatory blood pressure measurement < or = 85 mmHg) approximately doubled following the addition of HCTZ (12.5 mg = 57.6% and 25 mg = 69.5%).

CONCLUSION

Combination of olmesartan 20 mg with HCTZ provides significantly better 24-h blood pressure reduction than olmesartan monotherapy in patients with mild-to-moderate hypertension. Moreover, increasing the dose of HCTZ from 12.5 to 25 mg is a reasonable step to reach better daytime and night-time blood pressure control.