Diminished nocturnal decline in blood pressure in elderly hypertensive patients with left ventricular hypertrophy

Prediction of atrial fibrillation in patients with hypertension: A comprehensive comparison of office and ambulatory blood pressure measurements

Hypertension is associated with the development of atrial fibrillation (AF). Evidence has shown that reverse dipping pattern, an abnormal increase of night-time blood pressure (BP) comparing to daytime BP, is associated with cardiovascular events. However, the relationship between diurnal changes in BP and AF has not been sufficiently explored. This paper aims to cross-sectionally explore the relationship between AF and ambulatory BP parameters, especially reverse dippers to the others, and further longitudinally analyze how BP patterns are associated to the risk of developing new-onset AF. Between February 2012 and March 2021, five out of 412 patients were identified of AF at baseline; four were reverse dippers (3.7%) and one was from the others (.3%). Cross-sectionally, the multivariate logistic regression analysis showed that reverse dippers were significantly more likely to have AF (odds ratio: 12.39, p = .030). After excluding patients with baseline AF, during the mean follow-up of 4.6 ± 3.0 years, seven patients developed AF. Longitudinally, the multivariate Cox regression analysis revealed that 24-h systolic BP (hazard ratio per 10 mmHg: 2.12, p = .015), night-time systolic BP (hazard ratio per 10 mmHg: 2.27, p = .002), and presentation of reverse dipping (hazard ratio: 5.25, p = .042) were independently associated with new-onset AF. None of the office BP measurements were associated with new-onset AF. While ambulatory BP measurements were better predictors for the incidence of AF, careful management is necessary for reverse dippers as they are at high risk of developing AF.

Arterial Blood Pressure Variability and Other Vascular Factors Contribution to the Cognitive Decline in Parkinson's Disease

Dementia is one of the most disabling non-motor symptoms in Parkinson’s disease (PD). Unlike in Alzheimer’s disease, the vascular pathology in PD is less documented. Due to the uncertain role of commonly investigated metabolic or vascular factors, e.g., hypertension or diabetes, other factors corresponding to PD dementia have been proposed. Associated dysautonomia and dopaminergic treatment seem to have an impact on diurnal blood pressure (BP) variability, which may presumably contribute to white matter hyperintensities (WMH) development and cognitive decline. We aim to review possible vascular and metabolic factors: Renin-angiotensin-aldosterone system, vascular endothelial growth factor (VEGF), hyperhomocysteinemia (HHcy), as well as the dopaminergic treatment, in the etiopathogenesis of PD dementia. Additionally, we focus on the role of polymorphisms within the genes for catechol-O-methyltransferase (COMT), apolipoprotein E (APOE), vascular endothelial growth factor (VEGF), and for renin-angiotensin-aldosterone system components, and their contribution to cognitive decline in PD. Determining vascular risk factors and their contribution to the cognitive impairment in PD may result in screening, as well as preventive measures.

The Relationship between Non-Dipper Blood Pressure and Thoracic Aortic Diameter in Metabolic Syndrome

OBJECTIVE

Non-dipper hypertension is associated with increased cardiovascular morbidity and mortality. The purpose of this study was to evaluate the association of non-dipping hypertension with aortic diameter in patients with metabolic syndrome.

MATERIALS AND METHODS

This study included 70 hypertensive patients with metabolic syndrome. These patients were evaluated with 24-h blood pressure Holter monitoring and divided into two groups of 35 patients each. Aortic diameter was measured by M-mode and two-dimensional echocardiography. These parameters were compared between the two groups.

RESULTS

In the dipper group, there were 26 female and 9 male patients with a mean age of 55±11 years. In the non-dipper group, there were 25 female and 10 male patients with a mean age of 56±11 years. No significant difference was found between the two groups in terms of basic characteristics. Non-dipper hypertensive patients had a higher thoracic aortic diameter value than dipper patients (35.6±2.4 and 33.23±1.1, p<0.01).

CONCLUSION

These findings suggest that thoracic aortic diameter value is higher in patients with non-dipper hypertension.

Fine particulate matter results in hemodynamic changes in subjects with blunted nocturnal blood pressure dipping

Particulate matter with aerodynamic diameter of <2.5 μm (PM2.5) is associated with blood pressure and hemodynamic changes. Blunted nocturnal blood pressure dipping is a major risk factor for cardiovascular events; limited information is available on whether PM2.5 exposure-related hemodynamic changes vary with day-night blood pressure circadian rhythms. In this study, we enrolled 161 subjects and monitored the changes in ambulatory blood pressure and hemodynamics for 24h. The day-night blood pressure and cardiovascular metrics were calculated according to the sleep-wake cycles logged in the subject׳s diary. The effects of PM2.5 exposure on blood pressure and hemodynamic changes were analyzed using generalized linear mixed-effect model. After adjusting for potential confounders, a 10-μg/m(3) increase in PM2.5 was associated with 1.0 mmHg [95% confidence interval (CI): 0.2-1.8 mmHg] narrowing in the pulse pressure, 3.1% (95% CI: 1.4-4.8%) decrease in the maximum rate of left ventricular pressure rise, and 3.6% (95% CI: 1.6-5.7%) increase in systemic vascular resistance among 79 subjects with nocturnal blood pressure dip of <10%. In contrast, PM2.5 was not associated with any changes in cardiovascular metrics among 82 subjects with nocturnal blood pressure dip of ≥10%. Our findings demonstrate that short-term exposure to PM2.5 contributes to pulse pressure narrowing along with cardiac and vasomotor dysfunctions in subjects with nocturnal blood pressure dip of <10%.

Ambulatory blood pressure monitoring and prognosis in the management of essential hypertension

Over the past decade, several prospective outcome studies have demonstrated that ambulatory blood pressure measurements provide a better prediction of major cardiovascular events compared with clinic blood pressure measurements. This review summarizes the advantages of ambulatory blood pressure over clinic blood pressure to predict outcome in untreated and treated hypertensive subjects. Based on available evidence, an operational flow-chart in order to interpret results of ambulatory blood pressure for a better management of these subjects is suggested.

The effect of non-dipper and dipper blood pressure patterns on aortic elasticity in patients with metabolic syndrome

The purpose of this study was to evaluate the effect of blood pressure (BP) rhythm on aortic functions in patients with metabolic syndrome. Seventy patients with newly diagnosed hypertension who fulfilled the metabolic syndrome criteria according to the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP/ATP-III) were evaluated with 24-hour BP holter monitoring. According to BP rhythm, 35 patients with dipper BP pattern and 35 patients with non-dipper BP pattern were enrolled as two groups in our study. Systolic and diastolic diameters of the ascending aorta were measured by M-mode echocardiography and aortic functions (aortic strain, distensibility, and stiffness index) were calculated. The nocturnal systolic and diastolic BPs were significantly higher in non-dipper patients than the dipper group. According to clinical parameters including age, gender, height, weight, body mass index, waist circumference, clinical systolic, and diastolic BPs, we did not find significantly difference between the two groups. Aortic strain was significantly higher (6.63 ± 3.37 vs. 1.81 ± 0.92; P < .0001) and aortic distensibility was lower (2.38 ± 1.18 cm(-2)/dyn/10(-6) and 6.66 ± 3.67 cm(-2)/dyn/10(-6); P < .001) in non-dipper group. These findings suggest that aortic functions were prominently deteriorated in non-dipper hypertensive patients than dippers with metabolic syndrome.

Serum urotensin II levels in patients with non-dipper hypertension

Hypertension terms "dipper" and "non-dipper" are propounded by the change that occurs during ambulatory blood pressure (BP) monitoring. The purpose of this study is to present whether the serum urotensin II levels are different in patients with dipper and non-dipper hypertension and to put forward the effects causing this difference, if there are any. Patients recently diagnosed with hypertension were included in the study. With ambulatory BP monitoring, 81 patients with high BP were divided into two groups, dipper (n = 40) and non-dipper (n = 41). Serum urotensin II levels were analyzed by ELISA method. Serum urotensin II levels were higher in patients with non-dipper hypertension than in patients with dipper hypertension (204 [106-533] vs. 140 [96-309], P = .004). There was a positive correlation between total systolic BP and serum urotensin II levels (r = 0.408 and P = .009), but the relation in the non-dipper hypertension group was not significant (r = 0.194 and P = .2). In conclusion, serum urotensin II levels were higher in non-dipper HT patients than dipper HT patients. This higher urotensin II level might be responsible for poor prognoses.

Renal histopathology of a baboon model with type 2 diabetes

Naturally occurring type 2 diabetes has been found in a colony of baboons. Ongoing characterization of the baboon colony maintained at the Southwest National Primate Research Center has revealed a significant range of glucose sensitivity with some animals clearly diabetic.   Seven baboons, four with diabetes and three without diabetes, underwent histopathological investigation. Three diabetic animals were diagnosed using fasting blood glucose, hemoglobin A1C, and intravenous glucose tolerance test, and a fourth one was known to have hyperglycemia. One control baboon and three baboons with diabetes had microalbuminuria. On kidney biopsy, diabetic baboons had thickening of the glomerular basement membrane and mesangial matrix expansion compared to controls. Immunohistochemistry showed the diabetic animals had increased mesangial expression of cellular fibronectin ED-A. Two diabetic animals with microalbuminuria had evidence of mesangiolysis with the formation of an early nodule. One diabetic animal had a Kimmestiel-Wilson nodule. We conclude that the baboon represents a useful primate model of diabetes and nephropathy that resembles the nephropathy associated with type 2 diabetes in humans.

Resting sympathetic outflow does not predict the morning blood pressure surge in hypertension

OBJECTIVE

The blood pressure (BP) rise on awakening (morning surge) might be a predictor of hypertension-related cardiovascular complications. Previous studies suggest that the autonomic nervous system may contribute to the early morning BP increase. We tested the hypothesis that resting sympathetic outflow [assessed by direct measures of intraneural sympathetic nerve activity (SNA)] may help predict the morning BP surge in hypertension.

METHODS

We measured muscle SNA (MSNA), heart rate (HR) and BP during undisturbed supine rest in 68 newly diagnosed untreated hypertensive patients (53 men and 15 women, age 40 ± 3 years, BMI 27 ± 1 kg/m(2), mean ± SEM). The morning BP surge was defined as the difference between the morning BP and the pre-awake BP.

RESULTS

SBP averaged 143 ± 3 mmHg for daytime and 126 ± 2 mmHg for night-time. Mean HR was 81 ± 2 beats/min for daytime and 69 ± 2 beats/min for night-time. Average MSNA was 32 ± 2 bursts/min., SBP morning surge 19 ± 2 mmHg and HR morning surge 14 ± 2 beats/min. In univariate analysis, MSNA correlated with daytime SBP (r = 0.28, P = 0.02); night-time SBP (r = 0.26, P = 0.03); daytime HR (r = 0.28, P = 0.02); and night-time HR (r = 0.26, P = 0.03). Multivariate analysis, taking into consideration age, BMI and sex, revealed that MSNA was independently related to both daytime (P = 0.006) and night-time HR (P = 0.02), but not to ambulatory SBP. The morning surge of SBP and HR was not related to MSNA (r = 0.01 and r = 0.07, respectively, P = NS).

CONCLUSION

In patients with essential hypertension, MSNA is related to both daytime and night-time HR, but not to the morning BP surge.

Cystatin C and blood pressure: results of 24 h ambulatory blood pressure monitoring

BACKGROUND

The relationship between kidney function and blood pressure (BP) components has been studied in chronic kidney disease patients. Whether cystatin C, a marker of kidney function, is associated in the normal range with systolic BP (SBP), diastolic BP (DBP), and pulse pressure (PP) obtained using ambulatory blood pressure monitoring has not been previously studied.

METHODS

The sample subjects were 53 males and 34 females, mean age was 59.3+/-13.5 years. 76% were receiving antihypertensive drug treatment. Kidney function was evaluated by measuring serum cystatin C. Microalbuminuria was measured in a 24h urine collection. Glomerular filtration rate (GFR) was estimated using the abbreviated Modification of Diet in Renal Disease equations. The ambulatory BP was measured non-invasively for 24h by the Spacelab devices programmed to measure BP every 15 min during daytime and every 20 min during nighttime.

RESULTS

The highest quartile of cystatin C distribution showed an older age and worsel parameters of renal function (cystatin C, serum creatinine and GFR) than the other groups. No differences for gender or diabetes were found. 24h SBP and PP were higher in the fourth quartile compared to the fist one (p<0.01). 24h DBP was lower for the patients in the fourth quartile of cystatin C compared which any one of the other groups (p<0.001). The relationship between cystatin C, as well as GFR, with SBP and PP was statistically significant as renal function comes down. Contrariwise, as cystatin C increases DBP declines; but the correlation with GFR measured through MDRD 4 is not significant. In the same way, no correlation was found for GFR and microalbuminuria, but there was a statistically significant positive relationship between cystatin C and microalbuminuria severity (p<0.01). Multivariate regression analysis confirms these findings.

CONCLUSIONS

Both SBP and pulse pressure were significantly associated with kidney function. DBP was negatively correlated with cystatin C concentrations but not with GFR. Cystatin C shows a positive relationship with microalbuminura severity. Cystatin C might have cardiovascular effects beyond its use as a marker of the renal function.

Cardiovascular disease, diabetes and established risk factors among populations of sub-Saharan African descent in Europe: a literature review

Background

Most European countries are ethnically and culturally diverse. Globally, cardiovascular disease (CVD) is the leading cause of death. The major risk factors for CVD have been well established. This picture holds true for all regions of the world and in different ethnic groups. However, the prevalence of CVD and related risk factors vary among ethnic groups.

Methods

This article provides a review of current understanding of the epidemiology of vascular disease, principally coronary heart disease (CHD), stroke and related risk factors among populations of Sub-Sahara African descent (henceforth, African descent) in comparison with the European populations in Europe.

Results

Compared with European populations, populations of African descent have an increased risk of stroke, whereas CHD is less common. They also have higher rates of hypertension and diabetes than European populations. Obesity is highly prevalent, but smoking rate is lower among African descent women. Older people of African descent have more favourable lipid profile and dietary habits than their European counterparts. Alcohol consumption is less common among populations of African descent. The rate of physical activity differs between European countries. Dutch African-Suriname men and women are less physically active than the White-Dutch whereas British African women are more physically active than women in the general population. Literature on psychosocial stress shows inconsistent results.

Conclusion

Hypertension and diabetes are highly prevalent among African populations, which may explain their high rate of stroke in Europe. The relatively low rate of CHD may be explained by the low rates of other risk factors including a more favourable lipid profile and the low prevalence of smoking. The risk factors are changing, and on the whole, getting worse especially among African women. Cohort studies and clinical trials are therefore needed among these groups to determine the relative contribution of vascular risk factors, and to help guide the prevention efforts. There is a clear need for intervention studies among these populations in Europe.

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.

Circadian Variation in Stroke Onset: Identical Temporal Pattern in Ischemic and Hemorrhagic Events

Stroke is the culmination of a heterogeneous group of cerebrovascular diseases that is manifested as ischemia or hemorrhage of one or more blood vessels of the brain. The occurrence of many acute cardiovascular events--such as myocardial infarction, sudden cardiac death, pulmonary embolism, critical limb ischemia, and aortic aneurysm rupture--exhibits prominent 24 h patterning, with a major morning peak and secondary early evening peak. The incidence of stroke exhibits the same 24 h pattern. Although ischemic and hemorrhagic strokes are different entities and are characterized by different pathophysiological mechanisms, they share an identical double-peak 24 h pattern. A constellation of endogenous circadian rhythms and exogenous cyclic factors are involved. The staging of the circadian rhythms in vascular tone, coagulative balance, and blood pressure plus temporal patterns in posture, physical activity, emotional stress, and medication effects play central and/or triggering roles. Features of the circadian rhythm of blood pressure, in terms of their chronic and acute effects on cerebral vessels, and of coagulation are especially important. Clinical medicine has been most concerned with the prevention of stroke in the morning, when population-based studies show it is of greatest risk during the 24 h; however, improved protection of at-risk patients against stroke in the early evening, the second most vulnerable time of cerebrovascular accidents, has received relatively little attention thus far.

Influence of nifedipine coat-core and amlodipine on systemic arterial stiffness modulated by sympathetic and parasympathetic activity in hypertensive patients

The aim of this study was to compare the effects of nifedipine coat-core (once daily formulation) and amlodipine on systemic arterial stiffness in patients with hypertension. Study drugs were assigned by the randomized open-label crossover method. After the blood pressure was maintained below 130/85 mm Hg for 8 months by treatment with either drug in 48 hypertensive patients (aged 63.2+/-6.9 years; 64.5% men), they were switched to the other drug for another 8 months. The blood pressure, heart rate, plasma catecholamine level and brachial-ankle pulse wave velocity were measured before and after a bicycle ergometer testing. Heart rate recovery was calculated from the change of the heart rate after treadmill exercise testing. The high-frequency and low-frequency components of the heart rate variability spectrum were analyzed from 24-h Holter electrocardiograms. The change of blood pressure after exercise testing showed no significant difference between the two medications. However, the increases of heart rate, noradrenalin and branchial-ankle pulse wave velocity after exercise were significantly smaller with nifedipine treatment than with amlodipine (P=0.0472, P=0.006 and P=0.0472, respectively). Heart rate recovery was significantly faster with nifedipine treatment (P=0.0280). The nighttime high-frequency component of heart rate variability was significantly larger after nifedipine treatment than after amlodipine (P=0.0259), while the nighttime low/high-frequency ratio was significantly smaller with nifedipine (P=0.0429). Nifedipine reduced functional arterial stiffness and improved heart rate recovery by altering the autonomic activity balance in hypertensive patients.

Circadian variation of blood pressure: the basis for the chronotherapy of hypertension

Ambulatory blood pressure (BP) measurements present a close correlation with target organ damage and cardiovascular events, including myocardial infarction, stroke and cardiovascular mortality. With the use of this measurement technique, a significant circadian variation has been shown to characterize BP. This circadian BP variation, although affected by a variety of external factors, represents the influence of internal factors such as ethnicity, gender, autonomic nervous system tone, vasoactive hormones, and hematologic and renal variables. In most individuals, BP presents a morning increase, a small post-prandial valley, and a deeper descent during nocturnal rest. However, under certain pathophysiological conditions, the nocturnal BP decline may be reduced or even reversed. This cannot be determined by traditional clinical or home BP assessments. Subjects with a diminished nocturnal BP decline (non-dipper pattern) have a significantly worse prognosis than the ones with a normal dipper pattern. In particular, the non-dipper circadian BP pattern represents a risk factor for left ventricular hypertrophy, microalbuminuria, cerebrovascular disease, congestive heart failure, vascular dementia and myocardial infarction. The normalization of the circadian BP pattern to a dipper profile is a novel therapeutic goal, and accumulating medical evidence suggests this can delay the progression towards the renal and cardiovascular pathology known to be a consequence of the non-dipper BP pattern. The features of the circadian BP profile have direct implications for improving the drug-delivery of antihypertensive therapies as well as the qualification of patients for medication trials and assessment.

[Abnormal patterns of diurnal blood pressure variation and cardiovascular remodeling in elderly hypertensive patients]

Hypertension causes left ventricular hypertrophy and increases in large artery stiffness with ageing, both of which are cardiovascular risks. We studied cardiovascular remodeling in elderly hypertensive patients by measuring blood brain natriuretic peptide (BNP), left ventricular mass indices (LVMI), pulse wave velocities (PWV), and ambulatory blood pressures. We focused on ageing and sex-differences. Both LVMI and PWV correlated significantly with nocturnal blood pressures, which in turn correlated with BNP levels. Thus, BNP might be a candidate for a surrogate endpoint of target organ damage in elderly cases of hypertension. Left ventricular hypertrophy progressed with ageing more in women. Systolic blood pressures in women were shown to rise abruptly after menopause and to surpass those in men. However, more non-dippers were observed in men, suggesting that the absolute value of nocturnal blood pressure is a determinant of left ventricular hypertrophy. PWV accelerated with ageing, but it did not correlate with LVMI, suggesting that progression of cardiac remodeling with ageing was relatively independent of vascular remodeling. Finally, the greater mortality in elderly women might be associated with progressive left ventricular hypertrophy.

Role of sleep-wake cycle on blood pressure circadian rhythms and hypertension

Stages of different depth characterize the temporal organization of sleep. Each stage exerts an effect on blood pressure (BP) regulation and contributes to its 24-h variation. The main determinant of the circadian influences of sleep and wakefulness on BP is the daytime sympathetic and nighttime parasympathetic prevalence, but many other physiologic mechanisms known either to induce sleep or determine arousal may play an important role in the mediation of sleep influences on BP. Alteration of one or more of such mechanisms may be reflected in altered circadian BP rhythms. Sleep- and arousal-related mechanisms and phenomena that affect circadian BP rhythms include neurohumoral sleep factors (arginine vasopressin, vasoactive intestinal peptide, somatotropin, insulin, steroid hormones and metabolites, and serotonin among others) and waking factors (corticotropin-releasing factor, adrenocorticotropin, thyrotropin-releasing hormone, endogenous opioids, and prostaglandin (E(2))). Pathologic respiratory variations (sleep-disordered breathing) and insomnia are major causes of the sleep-related alteration of the circadian BP profile, including loss of the expected normal decline in BP by 10-20% from the daytime level. A great number of medical disorders can cause insomnia, but objective sleep studies have been performed only in a minority of them. Overall, the sleep-related pathophysiological mechanisms actually involved in causing altered circadian BP rhythms in different normotensive and hypertensive conditions are not completely understood. In any case, changes in the circadian BP rhythm are known to be strongly related to one's risk of cardiovascular morbidity and mortality, thus representing strong prognostic indicators worthy of further investigation.

Endothelial dysfunction and circadian blood pressure rhythmicity in young heart transplant recipients

Blood pressure variability correlates with circadian rhythmicity in endothelium-derived nitric oxide (NO) production in adults. Young, hypertensive orthotopic heart transplant (OHT) patients have functional abnormalities in NO-dependent signaling pathways that lead to reduced NO bioavailability and endothelial dysfunction. Following acute intravenous infusion of L: -arginine, the amino acid substrate for NO, OHT patients normalize blood pressure (BP) and endothelial function. However, the effects of chronic L: -arginine infusion on circadian BP rhythmicity and endothelial function in OHT patients have not been described. Six OHT patients (9-29 years old), and seven healthy control subjects (19-28 years old) were admitted for 48 hours. Systolic, diastolic, and mean blood pressures (MBP) were recorded hourly. Urine samples were obtained to measure nitrates/nitrites (NO(X)). Brachial artery flow-mediated vasodilatation (FMD; an index of endothelial function) and left ventricular ejection fraction (LVEF) were measured 0, 23, and 48 hours after admission. Intravenous L: -arginine HC1 was infused continuously beginning 24 hours after admission in all subjects. The incidence (50%) and degree (12.0 +/- 9.2%) of nocturnal MBP dipping was significantly less in OHT patients than control subjects. Furthermore, FMD was significantly reduced in OHT patients compared to controls (3.2 +/- 1.1 vs 7.2 +/- 3.1%, p = 0.01). L: -Arginine infusion had no significant effect on 24-hour MBP, LVEF, or nocturnal dipping status in any subject; however, L: -arginine normalized FMD in OHT patients (7.4 +/- 1.8%). Circadian BP variability and endothelial function are impaired in young cardiac transplant patients with medically controlled hypertension, and L: -arginine administration reverses endothelial dysfunction.

Circadian Rhythms in the CNS and Peripheral Clock Disorders: Role of the Biological Clock in Cardiovascular Diseases

The cardiovascular diseases are closely related to circadian rhythm, which is under the control of the biological clock. Clock genes show circadian oscillation not only in the suprachiasmatic nucleus but also in peripheral tissues, suggesting the existence of the peripheral clock. We previously demonstrated that plasminogen activator inhibitor-1 (PAI-1) might be an output gene of the peripheral clock. To further elucidate the functional relevance of the peripheral clock in the cardiovascular system, we screened target genes of the peripheral clock by cDNA microarray analysis. A total of 29 genes including transcription factor, growth factors, and membrane receptors were upregulated by CLOCK/BMAL and showed circadian oscillation. These results suggest that cardiovascular systems have their own peripheral clocks, and at least in part, they may regulate the circadian oscillation of cardiovascular function directly. These results potentially provide a molecular basis for the circadian variation of cardiovascular function and novel strategies for the prevention and treatment of cardiovascular diseases.

Aortic Elastic Properties in Patients With Hypertensive Response to Exercise

BACKGROUND

The aim of this study was to evaluate whether there is a relationship between aortic elastic properties in patients with a suggestive response to treadmill exercise testing.

METHODS AND RESULTS

The study group comprised 32 patients suggesting hypertensive response to exercise and 20 patients suggesting normal blood pressure response to treadmill exercise testing. Baseline demographic characteristics were similar in both groups. However, the mean aortic stiffness index of patients suggesting hypertensive response to treadmill exercise testing was significantly higher (4.8+/-1.26 vs 2.36+/-1.09; p=0.001) whereas aortic distensibility was significantly lower (12.82 +/-5.84 vs 22.64+/-14.54; p=0.001) than the control group. The aortic strain of patients with hypertensive response to exercise was lower than the control group (12+/-3% vs 19.2+/-5%, p<0.001). The left ventricular mass (LVM) of these patients was also higher than control group (206.5+/-46.3 vs 134.2+/-19.97; p=0.01). A negative correlation between LVM and distensibility was found (r=-0.64; p=0.001) well as a positive correlation between LVM and aortic stiffness index (r=0.51; p=0.004) in patients suggesting hypertensive response to exercise. Pressure--rate product was also found to be correlated with LVM (r=0.47; p=0.006).

CONCLUSION

Elastic properties of the aorta may be impaired in subjects showing exaggerated blood pressure response to exercise long before clinically manifest hypertension, particularly if the LVM is increased.

Does nocturnal blood pressure fall in people of African and South Asian descent differ from that in European white populations? A systematic review and meta-analysis

OBJECTIVE

To assess whether nocturnal blood pressure fall in people of African (Black) and South Asian descent differs from that of the European origin white populations (White).

METHODS

A systematic literature review was carried out using Medline 1966-2003 and Embase 1980-2003, and citations from references. The meta-analysis was performed using Cochrane review manager software (RevMan version 4.2; The Cochrane Collaboration, Oxford, UK).

RESULTS

Seventeen studies were identified; 11 studies from the USA, one from the USA and Canada, and six studies from the United Kingdom. The mean percentage systolic blood pressure (SBP) nocturnal fall was below 10% (non-dipping) in 10 of 17 studies (59%) and the diastolic blood pressure (DBP) nocturnal fall was below 10% in four of 16 studies (25%) in Blacks compared with four of 17 studies (24%) in SBP and none in DBP nocturnal falls in Whites. Compared with Whites, Blacks had a significantly lower mean percentage nocturnal fall; the overall weighted mean difference in SBP was -3.07 (95% confidence interval, -3.81, -2.33; P < 0.00001) and in DBP was -2.98 (95% confidence interval, -3.97, -2.00; P < 0.00001). Two studies on South Asians showed a higher SBP but a similar mean DBP nocturnal fall compared with Whites.

CONCLUSION

Smaller nocturnal blood pressure falls and a higher prevalence of non-dipping may contribute to the higher levels of hypertension complications seen in Black people. No such phenomenon was seen in South Asians but more research is needed to explore their higher stroke mortality.

Nocturnal blood pressure decrease is associated with increased regional cerebral blood flow in patients with a history of ischemic stroke

BACKGROUND

It remains controversial whether there is a J-shaped relationship between blood pressure and recurrent stroke among patients with a recent history of ischemic stroke.

OBJECTIVE

To investigate the relationship between regional cerebral blood flow (rCBF) and the dipping of nocturnal blood pressure in patients receiving antihypertensive treatment after ischemic stroke.

METHODS AND RESULTS

Forty-seven patients with a previous history of ischemic stroke and 37 patients with a history of non-ischemic stroke underwent 24-h ambulatory blood pressure monitoring and rCBF measurement with single photon emission computed tomography. Of the 47 patients with ischemic stroke, 30 were diagnosed as having suffered atheromatous or embolic stroke, and 37 had an ischemic lesion in the territory of the carotid artery. Systolic and diastolic blood pressures during daytime and night-time were controlled at less than 140/90 mmHg by a low-salt diet or long-acting antihypertensive agents, or both. In patients with ischemic stroke, there were significant negative correlations between the percentage change in nocturnal blood pressure and rCBFs in the thalamus (r = -0.33, P = 0.02), putamen (r = -0.34, P = 0.02) and cerebral cortex (r = -0.31, P = 0.03). Multivariate analysis revealed that only the percentage change in nocturnal blood pressure was related to rCBF. There was a significant positive correlation between rCBFs in the thalamus and the cerebral cortex (r = 0.74, P < 0.05). In patients with non-ischemic stroke, there was no significant correlation between the percentage change in nocturnal blood pressure and rCBFs.

CONCLUSIONS

These findings indicate that the decrease in nocturnal blood pressure is associated with the increase in rCBF in patients with a history of ischemic stroke in the territory of the carotid artery.

Blood pressure changes in acute haemorrhagic stroke

The relationship between hypertension and cerebrovascular disease is well established. As blood pressure is a dynamic and continually distributed variable, 24 h ambulatory blood pressure monitoring may be valuable as a risk stratifying tool in determining the "hypertensive load" as assessed by the presence of dipping or non-dipping status of an individual. Indeed, the association between reduced nocturnal blood pressure dipping and increased target organ damage is well established. Raised blood pressures are often seen in those presenting with strokes, although the precise mechanisms are uncertain. The relationship between intracerebral haemorrhage, which accounts for up to 15% of strokes in Caucasians, and blood pressure patterns is not well known. Understanding these inherent diurnal rhythms of blood pressure variation could help us unravel their significance and impact on cerebrovascular disease.

The influence of circadian blood pressure changes on aortic distensibility and left ventricular diastolic function in hypertensive individuals

BACKGROUND

Failure to decrease blood pressure (BP) normally during nighttime, which is called non-dipper, in hypertensive individuals is associated with higher cardiovascular morbidity and mortality. In addition, non-dipper BP leads to structural changes in the left ventricle; however, the influences of non-dipper BP on aortic elastic properties and left ventricular diastolic function have not been studied yet.

METHODS

In this study, we evaluated aortic elastic properties and left ventricular diastolic function of 22 subjects with non-dipper hypertension, and 15 subjects with dipper hypertension using transthoracic second harmonic standard and tissue 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 standard 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 nighttime BPs were significantly greater in non-dipper group than those were in dipper group. Left ventricular diastolic parameters obtained by both standard and tissue Doppler did not differ between the non-dipper and dipper groups. However, aortic distensibility was found to be slightly lower (4.1+/-2.4 vs. 4.9+/-1.9, p=0.08), and aortic stiffness index (6.3+/-0.5 vs. 6.1+/-0.4, p=0.08) and elastic modulus (6.2+/-2.5 vs. 4.8+/-2.3, p=0.08; groups non-dipper and dipper respectively) higher in non-dipper group than in dipper group. However, these differences were not statistically significant.

CONCLUSION

Left ventricular remodeling and diastolic function were similar in patients with non-dipper and dipper hypertension. However, aortic elastic properties were slightly impaired in non-dipper hypertensives than those were in dipper ones, but these differences did not reach statistically significance.

The Frequency of Combined Target Organ Damage and the Beneficial Effect of Ambulatory Blood Pressure Monitoring in Never Treated Mild-to-Moderate Hypertensive Patients

The aim of this study was to determine the frequency of target organ damage (TOD) and the beneficial properties of ambulatory blood pressure monitoring (ABPM) for detecting patients who are at high risk for TOD and cardiovascular disease in never treated mild-to-moderate hypertension. Sixty-seven patients (28 males and 39 females, mean age, 49.6 +/- 9.5 years) were divided into two groups, dippers (group I, n = 43) and nondippers (group II, n = 24), according to nocturnal blood pressure (BP) reduction of less than 10%. The groups were compared with respect to demographic and laboratory data and the signs of TOD (microalbuminuria, left ventricular hypertrophy, and retinopathy). We also tested the relationship between ABPM and clinic BP findings with TOD. Group I had significantly lower values than group II for serum fibrinogen (0.28 +/- 0.06 versus 0.32 +/- 0.06 g/L, P = 0.02), uric acid (0.18 +/- 0.05 versus 0.25 +/- 0.11 mmo/L, P = 0.01), urinary sodium excretion (133.7 +/- 45.2 versus 161.8 +/- 52.2 mmol/L, P = 0.02), urinary albumin excretion (17.5 +/- 14.2 versus 31.3 +/- 19.7 mg/24-h, P = 0.001), left ventricular mass index (111.8 +/- 31.0 versus 128.7 +/- 36.6 g/m(2), P = 0.05), and the prevalence of hypertensive retinopathy (51% versus 83%, P = 0.01). The frequency of the combination of all three signs of TOD (microalbuminuria, left ventricular hypertrophy, and hypertensive retinopathy) was higher in nondippers than in dippers (71.4% versus 30%, P = 0.04). We suggest ABPM may provide clinical information to detect patients prone to develop cardiovascular risks and TOD in newly diagnosed mild-to-moderate hypertension.

Nighttime blood pressure fall in renal disease patients

OBJECTIVE

There are controversial reports in the prevalence of abnormal nighttime blood pressure fall in renal patients. It has been evaluated nocturnal BP in renal patients using 24 h blood pressure monitoring (ABPM) in comparison with nontreated control subjects either normotensives or hypertensives.

DESIGN AND METHODS

It has been reviewed 137 ABPM studies performed in renal patients (47.8 +/- 15.4 years, 76 men and 61 women). The control group includes 119 subjects without kidney disease, 65 were normotensives, and 49 were hypertensives, aged 46.8 +/- 12.1 years, 59 men and 60 women. The ambulatory BP was measured noninvasively for 24h by the SpaceLabs 90207 device programmed to measure BP every 15 min during daytime and every 20 min during nighttime. The definition of daytime and nighttime was made on the basis of wakefulness and sleep or bed rest periods, obtained from a diary kept by each subject.

RESULTS

SBP, but not DBP, was higher (133.9/81.7) in renal disease patients when compared to nonrenal subjects (127.9/80.8, p < 0.01). When the control group was split into normotensive and hypertensive patients there were still significant differences, but hypertensives had higher BP than renal disease patients (139.0/89.7, p < 0.05). Nocturnal SBP fall in renal disease patients was reduced (5.8%, p < 0.001) and so was DBP fall (11.1%, p < 0.001) compared with the overall nonrenal patients sample (SBP 10.8; DBP 15.3%). The frequency of nondipper status in renal disease patients (39.6%) was higher than in control patients (18.4%, p < 0.001). Nontreated normotensive renal disease patients did not show any difference in either SBP or DBP nighttime fall with respect to control normotensives. Neither do nontreated hypertensive renal patients as compared with control hypertensives. There were not differences between proteinuric and nonproteinuric patients in nocturnal BP fall. The same result was obtained when hypertensive and normotensive nontreated renal patients were compared. The presence of renal failure did not induce a reduction of nocturnal BP fall. Most of treated renal patients were mainly receiving drug therapy during the morning and frequently this was the single daily dose.

CONCLUSIONS

Altered diurnal rhythm should not be considered as a usual complication of renal disease. Inadequate antihypertensive pharmacotherapy could be related to the abnormalities of nighttime BP fall when it is detected.

[Continuous ambulatory monitoring of blood pressure and the left ventricular mass index in children with kidney diseases]

INTRODUCTION

Numerous epidemiological studies have shown that blood pressure (BP) is positively related to cardiovascular morbidity and mortality. Although the relationship between BP and the incidence of morbid events is consistent and highly significant, it is difficult to predict the absolute risk. Several studies have shown that the organ damage associated with hypertension correlate to a greater degree with 24 h average BP than with clinic BP and the most of them evaluated left ventricular hypertrophy in these patients.

OBJECTIVE

To evaluate the correlation between left ventricular mass index (LVMi) and BP, BP variability, pulse pressure (PP), BP load and hyperbaric index (HBI).

DESIGN AND METHODS

Ambulatory blood pressure monitoring (ABPM) was performed in 30 children with renal disease aged 12.7 +/- 5.5 years. Ten of them had normal renal function, 3 had renal transplant and 17 of them had end-stage renal disease and were on chronic haemodialysis. All of the patients were submitted to an echocardiographic evaluation and LVMi was calculated according to Penn convention. Ambulatory blood pressure monitoring was performed during the 24 h period and average values of systolic and diastolic BP were evaluated. As an index of variability of BP values we used standard deviation (SD) of mean. Evaluation of average BP values has some disadvantages--it does not take into account the peaks of blood pressure and the values are lower if the circadian rhythm of BP is preserved--for this reason BP load and HBI were evaluated as well. BP load represented the percentage of BPs exceeding the upper limits of normal and HBI the integrated area under the ambulatory BP curve. For the upper limits of normal was used 95th percentile from the multicenter study of German authors.

RESULTS

There was no correlation between LVMi and evaluated parameters.

CONCLUSIONS

The response of myocardium to chronic increase of the afterload is highly individual, and probably the role of genetics in this is very important. Echocardiography (LVMi) could not be used with certainty for the evaluation of ventricular mass.

Relevance of blood pressure variation in the circadian onset of cardiovascular events

Ambulatory blood pressure monitoring (ABPM) is a highly useful diagnostic tool as it can detect non-dipping and can distinguish masked hypertension, white-coat hypertension and sustained hypertension. Furthermore, measurement of blood pressure using ABPM has greater prognostic strength than single clinic blood pressure measurements. The Systolic Hypertension in Europe study, for example, found that elevation of ambulatory systolic blood pressure, but not conventional single cuff systolic blood pressure, by 10 mmHg was associated with adverse cardiovascular outcomes. Blood pressure follows a circadian rhythm, with peak levels during the morning hours. The morning period has also been associated with a greater risk for cardiovascular events compared with the rest of the 24 h. The morning surge in blood pressure, along with haemostatic changes that promote thrombosis, is believed to contribute to this heightened risk. Long-acting antihypertensive agents that provide blood pressure control throughout the 24-h dosing interval, including the morning hours, are the most appropriate therapeutic approach to hypertension. Direct comparative studies with telmisartan and other angiotensin-II receptor blockers and with amlodipine have shown that telmisartan has a long duration of action and controls blood pressure over the 24-h dosing period.

Relationship between diurnal blood pressure, renal hemodynamic function, and the renin-angiotensin system in type 1 diabetes

In patients with diabetes, altered diurnal blood pressure (BP) regulation (high night-to-day [N/D] ratio, or "nondipping") is associated with increases in albumin excretion and a decline in the glomerular filtration rate (GFR) by an unknown mechanism. Because it is known that renin angiotensin system (RAS) activation and defective glucose control contribute to adverse renal outcomes, we examined renal responses to high glucose and to manipulation of the RAS in adolescents (mean age 14 +/- 2 years) with uncomplicated type 1 diabetes, segregated into two groups on the basis of the presence or absence of normal N/D BP ratio. In the first experiment, renal hemodynamic comparisons were made during euglycemia (4-6 mmol/l) and hyperglycemia (9-11 mmol/l), maintained by modified clamp techniques. The induction of hyperglycemia resulted in a significant increase in GFR and filtration fraction (FF) in the high N/D ratio group. In the second experiment, we examined the renal response to graded angiotensin II (Ang II) infusion while subjects were euglycemic and salt replete. High N/D ratio was associated with an enhanced FF response to Ang II. In the third experiment, the N/D ratio and GFR were assessed after 3 weeks of ACE inhibition. This maneuver corrected the high N/D ratio, but it had no effect on glomerular hyperfiltration. These results suggest that RAS activation does not explain the hyperfiltration state, nor can it explain the poor outcomes, at least in this population. However, the observed deleterious hemodynamic responses to high glucose and Ang II and the insensitivity to ACE inhibition may, taken together, provide an explanation for the adverse renal outcomes in patients with type 1 diabetes and high N/D ratio.

[Seasonal variation in plasma fibrinogen in dipper and non-dipper patients with mild-moderate essential hypertension]

BACKGROUND AND OBJECTIVE

Increased plasma fibrinogen is recognized as a significant parameter for assessing the potential risk of myocardial infarction and stroke. A seasonal variation has been reported for plasma fibrinogen, with highest values occurring in the coldest months of the year. On the other hand, the lack of nocturnal decline in blood pressure has been associated with an increase in cardiovascular events. Accordingly, we have quantified the yearly variation in plasma fibrinogen in hypertensive patients classified according to their nocturnal decline in blood pressure.

PATIENTS AND METHOD

We studied 577 mild-to-moderate hypertensive patients (254 men), 53.8 13.8 years of age. Blood pressure was measured every 20 min during the day and every 30 min at night for 48 consecutive hours. Physical activity was simultaneously evaluated at 1-min intervals with a wrist actigraph. A complete blood test was performed on the same day before starting blood pressure monitoring. The circannual variation of plasma fibrinogen was established for all patients as well as for subgroups of dippers (n = 287) and non-dippers (n = 290; patients with a nocturnal blood pressure decline < 10% of the diurnal mean) by multiple-component analysis.

RESULTS

For the whole group of hypertensive patients, plasma fibrinogen was characterized by a highly significant seasonal variation (p < 0.001), with a mean value of 324 mg/dl, double circannual amplitude (i.e, extent of predictable change along the year) of 75 mg/dl, and time of peak value on the first week of March. This circannual variation can be best represented by a model that includes components with periods of 12 and 6 months. The same model also characterized dippers as well as non-dippers, analyzed separately. Non-dippers showed higher plasma fibrinogen throughout the whole year as compared to dippers (p = 0.002).

CONCLUSIONS

The elevation of plasma fibrinogen in non-dipper patients as compared to dippers could support the association between the lack of nocturnal decline in blood pressure with an increase in cardiovascular events, since the circannual variation in fibrinogen is timely correlated with the reported yearly variation in coronary events.

Ambulatory pulse pressure is a relatively sleep-independent variable

OBJECTIVES

Characterization of sleep-induced pulse and mean arterial pressure (MAP) dip.

DESIGN

Prospective study of consecutive referred patients.

SETTING

Hypertension unit of community university hospital.

PARTICIPANTS

A total of 500 consecutive subjects referred to our unit for ambulatory blood pressure (BP) monitoring. There were 200 men and 300 women, the majority of which were treated hypertensives. Mean age was 59.7 +/- 16.6 years.

MAIN OUTCOME MEASURES

Effect of sleep on MAP and pulse pressure (PP).

RESULTS

Twenty-four hour MAP was 98 +/- 10 mmHg. Awake and asleep MAPs were 101 +/- 11 and 87 +/- 11 mmHg, respectively. Twenty-four hour, awake and asleep pulse pressures were 60 +/- 13, 61 +/- 13 and 58 +/- 13 mmHg, respectively. MAP dip was 14%, 95% confidence interval (CI) 13.4-14.6, whereas PP dip was 5%, 95% CI 4.1-5.8. Thus, the MAP dip was almost three times the PP dip (P < 0.0001). This held true for normotensives, hypertensives (treated and untreated), men, women and diabetic subjects.

CONCLUSIONS

Although pulse pressure is derived from BP, it is more stable during a 24-h period, with a lesser effect of sleep compared with MAP. This more rigid nature of the PP could explain its better prognostic value, compared to that of MAP.

Twenty-four-Hour blood pressure variability after acute ischemic stroke

In people who are healthy, circadian rhythm in blood pressure is well established, with a 10% to 20% decrease in systolic and diastolic blood pressure during nighttime. Deviations correlate with target organ disease such as left ventricular hypertrophy, retinopathy, renal disease, and stroke. Little is known about blood pressure and circadian patterns in stroke patients. This study examined 13 patients hospitalized after ischemic stroke and monitored 24-hour blood pressure with ambulatory blood pressure monitors programmed tocollect readings every 30 minutes. All subjects had an abnormal pattern in blood pressure that did not dip during nighttime. Blood pressure load, a reported indicator of risk for target organ damage, was exceeded in all subjects during daytime and nighttime. Thus stroke patients are at high risk for target organ disease including recurrent stroke. Hypertensive management of stroke patients requires further investigation.

Non-dipping in diabetic patients: insights from the siesta

Non-dipping, ie failure to lower blood pressure during sleep, has been found to be more prevalent in diabetic than in non-diabetic subjects. However, the reasons remain to be clarified. Diabetic patients may wake up more frequently during the night (for instance, due to nocturia). This may result in inclusion of awake blood pressure measurements in the night-time average and thus erroneously raise this average, causing misclassification of patients as non-dippers. However, non-dipping in diabetes may be due to blunted effect of sleep itself on blood pressure secondary to autonomic neuropathy. We undertook this study in order to further clarify this question. We studied 23 diabetic patients, and 23 matched controls who underwent 24-h ambulatory blood pressure monitoring, and reported taking an afternoon nap. Afternoon nap, by virtue of its short duration, is devoid of interruptions, and thus can be used as a model for tiled, non-interrupted sleep. We found that, both in diabetic patients and controls, blood pressure declined during the afternoon nap in a similar magnitude to the night-time decline. However, this decline was significantly blunted in the diabetic patients (13.9 +/- 2.2% decline in diastolic blood pressure during naptime in the diabetic patients, as compared with 24 +/- 2.3% decline in diastolic blood pressure during the siesta in the control group, P < 0.02). The blunted decline of blood pressure during the nap in diabetic patients demonstrates that non-dipping is due to the blunted effect of sleep itself. This can be another facet of autonomic dysfunction seen in diabetes mellitus.

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

The clinical significance of the extent of a decrease in nocturnal blood pressure (BP) and the resulting classification of hypertensives as "dipper" (decrease in BP >10% day BP) or "nondipper" (decrease in BP <10% day BP) has been questioned recently. The aim of our study was to evaluate if the extent of a nocturnal BP decrease, established on the basis of a single 24-hour BP monitoring, is related to cardiovascular remodeling in essential hypertension. We enrolled 253 never-treated essential hypertensives (24-hour BP > or = 140 and/or 90 mm Hg); for each patient we recorded 24-hour BP, left ventricular (LV) echocardiogram, Doppler transmitral flow velocities, and carotid-femoral pulse-wave velocities. A dipper BP profile was found in 161 patients, whereas 92 patients were nondippers. The 2 groups did not differ with regard to age, gender, body mass index, 24-hour and daytime BP, and 24-hour, daytime, and nighttime heart rate. All LV morphologic characteristics LV systolic and diastolic functional parameters, mitral Doppler-derived diastolic indexes, as well as carotid-femoral pulse-wave velocity, and aortic index distensibility were not significantly different between dippers and nondippers. The prevalence of LV hypertrophy and diastolic dysfunction was also similar between the 2 groups. The extent of a decrease in nocturnal BP did not correlate with any cardiovascular parameter. In conclusion, in never-treated hypertensives, the extent of a nocturnal BP decrease is not related to LV morpho-functional characteristics and aortic distensibility; therefore, the nondipping status established on the basis of a single 24-hour BP monitoring does not identify hypertensive patients with greater cardiovascular damage.

Noninvasive 24-hour ambulatory blood pressure monitoring: overview of technology and clinical applications

During the last 25 years, 24-hour noninvasive ambulatory blood pressure monitoring (ABPM) has evolved from a research tool of limited clinical use into an important tool for stratifying cardiovascular risk and guiding therapeutic decisions. Until recently, clinical use of ABPM focused on identifying patients with white-coat hypertension, but accumulated evidence now points to greater prognostic significance of ABPM in determining risk for target-organ damage compared with that of office blood pressure measurements. Clinicians involved in the care of patients with hypertension should familiarize themselves with the role of this technology and how to use it in an appropriate and cost-effective manner.