Prognostic value of ambulatory blood pressure monitoring in refractory hypertension: a prospective study

Prognostic impact of baseline and serial changes in electrocardiographic left ventricular hypertrophy in resistant hypertension

BACKGROUND

The prognostic value of electrocardiographic left ventricular hypertrophy (ECG-LVH) in resistant hypertension (RH) is unknown. The aim was to evaluate the importance of baseline and serial changes in ECG-LVH as predictors of cardiovascular morbidity and mortality in patients with RH.

METHODS

At baseline and during follow-up, 552 resistant hypertensive patients had 3 ECG-LVH criteria obtained: Sokolow-Lyon, Cornell voltage, and Cornell voltage-duration product. Primary end points were a composite of fatal and nonfatal cardiovascular events and all-cause and cardiovascular mortalities. Total strokes and coronary heart disease (CHD) events were secondary end points. Multiple Cox regression assessed the associations between time-varying ECG-LVH and subsequent end points.

RESULTS

After a median follow-up of 4.8 years, 70 patients died, 46 from cardiovascular causes; and 109 total cardiovascular events occurred, 46 strokes, and 44 CHD events. After adjustment for several cardiovascular risk factors, baseline Cornell voltage and product, but not Sokolow-Lyon voltage, were independent predictors of the composite end point and of all-cause and cardiovascular mortalities. Reductions of all ECG-LVH criteria were protective factors for the composite end point: a 1-SD (1.1 mV) reduction in Sokolow-Lyon voltage was associated with a 35% lower risk (95% CI 10%-53%) of cardiovascular events, whereas prevention or regression of Cornell product LVH criterion implied a 40% lower risk (95% CI 11%-60%). Baseline and serial changes in Sokolow-Lyon voltage were independent predictors of strokes, whereas Cornell voltage was predictive of CHD events.

CONCLUSIONS

Baseline and serial changes in ECG-LVH predict cardiovascular morbidity and mortality in RH patients. Antihypertensive treatment targeted at regression or prevention of ECG-LVH may improve prognosis.

Ambulatory blood pressure monitoring in type 2 diabetes and metabolic syndrome: a review

We reviewed the literature on ambulatory blood pressure (BP) monitoring in type 2 diabetes mellitus (T2DM) (focusing on organ damage progression, prognosis, white coat hypertension, and masked hypertension) and metabolic syndrome (MetS). In the text we reported 21 articles about T2DM and 11 about MetS, part of which were included in meta-analyses. In T2DM, individual studies and meta-analyses indicate that 24-h pulse pressure and reduced night-time BP fall or reverse dipping predict organ damage progression, total cardiovascular events and all-cause mortality. Moreover, white coat hypertension seems to be less frequent in T2DM and its impact on cardiovascular complications remains controversial. In contrast, masked hypertension is more frequent in T2DM and seems to be associated with increased organ damage. Some studies reported higher ambulatory BP in patients with MetS, but these patients were older and had higher clinical BP than those without MetS. With regard to the circadian BP profile, contrasting data have been reported, although pooled data suggest a higher risk of nondipping in patients with MetS.

Current options for the treatment of resistant hypertension

Patients with resistant hypertension are those who have uncontrolled blood pressure despite use of three or more antihypertensive medications, or those who require four or more medications to achieve control. When evaluating resistant hypertension it is important to rule out pseudoresistant hypertension that may result from factors including poor blood pressure measurement technique and the white coat effect. Potential contributing factors should be identified and reversed if possible, including obesity, excess alcohol intake and use of interfering medications such as NSAIDS, sympathomimetics and oral contraceptives. Modification of lifestyle factors such as weight loss, sodium restriction and physical activity is paramount for treatment success. Secondary causes of hypertension are common in this patient group and, therefore, appropriate screening tests should be carried out as necessary. Pharmacologic therapy is centered on combination therapy of medications from different mechanisms of action, especially diuretics, which are essential in maximizing antihypertensive effects. The role of mineralocorticoid antagonists is expanding, especially in patients with obstructive sleep apnea and obesity where aldosterone excess may be implicated. Finally, when appropriate, specialist referral may facilitate blood pressure reduction and the ability to meet target blood pressure goals.

Urinary albumin excretion is associated with true resistant hypertension

Resistant (or refractory) hypertension (RH) is a clinical diagnosis based on blood pressure (BP) office measurements. About one third of subjects with suspected RH have indeed pseudo-resistant hypertension and 24-h ambulatory-blood pressure-monitoring aids to precisely identify them. Our aim was to determine those clinical, laboratory or echocardiographic variables that may be associated with subjects with sustained hypertension (namely true RH). We carried out a cross-sectional analysis of 143 patients consecutively enrolled with the clinical diagnosis of RH. All patients underwent clinical-demographic, laboratory evaluation, 2D-echocardiography and 24-h ambulatory-blood pressure-monitoring. Pseudo-resistant hypertension or white-coat RH was defined if office BP was > or =140 and/or 90 mm Hg and 24-h BP <130/80 mm Hg. One-hundred and three (72%) patients had true RH and 40 (28%) patients had white-coat RH. True RH patients had significantly higher diabetes prevalence and higher office-systolic blood pressure (SBP) levels. Regarding target organ damage, left ventricular mass index (LVMI) and 24-h urinary albumin excretion (UAE) were also higher in true RH after adjustment for possible confounders (P=0.031 and P=0.012, respectively). In a logistic regression analysis, only office-SBP (multivariate OR (95%CI): 1.030 (1.003-1.057), P=0.030) and UAE (multivariate OR (95% CI): 2.376 (1.225-4.608), P=0.010) were independently associated with true RH. We conclude that true resistant hypertension is associated with silent target organ damage, especially UAE. In patients with suspected RH, assessment of 24 h ambulatory BP is the most accurate way to detect a population with high risk for target-organ damage.

Nocturnal blood pressure profiles among normotensive, controlled hypertensive and refractory hypertensive subjects

BACKGROUND

Nocturnal blood pressure abnormalities are independently associated with an increased risk of death and cardiovascular disease. It is unclear, however, whether they are related to the presence or severity of hypertension.

OBJECTIVES

To determine and compare the prevalence of sleep pattern disturbances in normotensive (NT) and hypertensive patients.

METHODS

The present cross-sectional study assessed the nocturnal blood pressure profiles from 24 h ambulatory blood pressure monitoring of refractory hypertensive (RH) (n=26), controlled hypertensive (CH) (n=52) and NT (n=52) subjects who were matched for age, sex and body mass index. Results are expressed as mean +/- SD or proportion, as appropriate.

RESULTS

During sleep, the percentage fall in mean arterial pressure was 15.1+/-6.1% in the NT group, 11.5+/-7.0% in the CH group and 7.7+/-7.7% in the RH group (P<0.0001). The corresponding proportions of nondipping were 25.0%, 42.3% and 61.5%, respectively (P=0.006), and those of nocturnal hypertension were 9.6%, 23.1% and 84.6%, respectively (P<0.0001). All pairwise comparisons of nocturnal blood pressure fall were significant. The proportion of subjects in the RH group who experienced a rise in nocturnal blood pressure (19.2%) was significantly greater than the proportions in the NT and CH groups (P=0.001), as was the proportion of subjects with nocturnal hypertension (P<0.0001). There was less extreme dipping in RH, although the difference was not statistically significant (P=0.08).

CONCLUSIONS

A significantly higher prevalence of nondipping, nocturnal hypertension and nocturnal blood pressure rising in RH was demonstrated. These sleep disturbances or independently, their cause, may account for the difficulties in attaining blood pressure control.

Ambulatory blood pressure monitoring predicts cardiovascular events in treated hypertensive patients--an Anglo-Scandinavian cardiac outcomes trial substudy

BACKGROUND

Results of the Anglo-Scandinavian cardiac outcomes trial-blood pressure lowering arm (ASCOT-BPLA) showed significantly lower rates of coronary and stroke events in individuals allocated an amlodipine-perindopril combination drug regimen than in those allocated an atenolol-thiazide combination drug regimen. The aims of the ambulatory blood pressure (ABP) substudy of ASCOT were to examine the impact of the two blood pressure (BP)- lowering regimens on ambulatory pressures, test to what extent the between-treatment differences in cardiovascular outcome could be attributed to differences in ABP and assess whether ABP provides predictive information additional to that of clinic blood pressure (CBP) in treated hypertensive patients.

METHODS AND RESULTS

One thousand, nine hundred and five patients from four ASCOT centres had repeated ABPs performed over a median follow-up period of 5.5 years. As in the whole ASCOT population, CBP values were lower in amlodipine-perindopril-treated patients compared with those treated with atenolol-thiazide [between-regimen difference [95% confidence intervals (CIs)]]: [-1.5 (-2.4 to -0.5)/-1.2 (-1.8 to +0.5) mmHg]. Daytime BP during follow-up was higher in patients treated with amlodipine-perindopril therapy [+1.1 (0.1-2.1)/+1.6 (0.8-2.3) mmHg]; night-time systolic, but not diastolic BP, was lower in patients treated with amlodipine-perindopril therapy [-2.2 (-3.4 to +0.9)/+0.8 (0.0-1.6) mmHg]. The relative risk of a cardiovascular event associated with a 1 SD increment in accumulated mean BP was 1.35 (1.18-1.53) for clinic systolic BP, 1.30 (1.14-1.49) for daytime systolic BP and 1.42 (1.24-1.62) for night-time systolic BP. With adjustment for baseline variables, treatment regimen and clinic systolic BP, the hazard ratios were 1.17 (1.00-1.36) and 1.25 (1.08-1.47) for daytime and night-time systolic BP, respectively. The between-regimen adjusted hazard ratio for cardiovascular events (amlodipine-perindopril therapy versus atenolol-thiazide therapy) was 0.74 (0.55-1.01) and increased to 0.81 (0.60-1.10) after further adjustment for clinic systolic BP. Further, adjustment for night-time systolic BP increased the hazard ratio to 0.85 (0.62-1.16).

CONCLUSION

The amlodipine-perindopril and atenolol-thiazide regimens had different effects on daytime and night-time ABP, which may have contributed to the lower rates of events in patients treated with amlodipine-perindopril therapy. Both CBP and ABP were significantly associated with rates of cardiovascular events. ABP nocturnal pressures provided complimentary and incremental utility over CBP in the prediction of cardiovascular risk in treated hypertensive patients. These data support the use of ABP to assess the effect of antihypertensive treatment in clinical practice.

Periodontal therapy reduces plasma levels of interleukin-6, C-reactive protein, and fibrinogen in patients with severe periodontitis and refractory arterial hypertension

BACKGROUND

Recent epidemiologic studies suggest that inflammation is the link between periodontal diseases and cardiovascular complications. This study aimed to evaluate the effects of non-surgical periodontal treatment on plasma levels of inflammatory markers (interleukin [IL]-6, C-reactive protein [CRP], and fibrinogen) in patients with severe periodontitis and refractory arterial hypertension.

METHODS

Twenty-two patients were examined and randomly divided into two groups. The test group was composed of 11 patients (mean age, 48.9 +/- 3.9 years) who received periodontal treatment, whereas the control group had 11 patients (mean age, 49.7 +/- 6.0 years) whose treatment was delayed for 3 months. Demographic and clinical periodontal data were collected, and blood tests were performed to measure the levels of IL-6, CRP, and fibrinogen at baseline and 3 months later.

RESULTS

The clinical results showed that the mean percentages of sites with bleeding on probing, probing depth (PD) 4 to 5 mm, PD > or =6 mm, clinical attachment loss (CAL) 4 to 5 mm, and CAL > or =6 mm were significantly reduced in the test group 3 months after periodontal treatment. There were no significant differences between the data at baseline and 3 months in the control group. Periodontal treatment significantly reduced the blood levels of fibrinogen, CRP, and IL-6 in the test group.

CONCLUSION

Non-surgical periodontal therapy was effective in improving periodontal clinical data and in reducing the plasma levels of IL-6, CRP, and fibrinogen in hypertensive patients with severe periodontitis.

Prognostic value of ventricular repolarization prolongation in resistant hypertension: a prospective cohort study

OBJECTIVE

The prognostic value of prolonged ventricular repolarization in patients with resistant hypertension is unknown. The aim of this prospective study was to investigate the usefulness of electrocardiographic QT-interval parameters as predictors of cardiovascular morbidity and mortality.

METHODS

At baseline, 538 resistant hypertensive patients had five QT-interval components measured in standard 12-lead ECGs: maximum QRS, QTpeak, QTend, JT and Tpeak-to-end-interval durations. Primary endpoints were a composite of fatal and nonfatal cardiovascular events, all-cause and cardiovascular mortalities. Multiple Cox regression assessed the associations between QT-interval parameters and subsequent endpoints.

RESULTS

After a median follow-up of 4.8 years, 69 (12.8%) patients died, 46 from cardiovascular causes, and 107 (19.9%) fatal or nonfatal cardiovascular events occurred. After adjustment for several traditional risk factors, including 24-h ambulatory systolic blood pressure, an increment of 1 SD (35 ms) in QTcend-interval was associated with hazard ratios of 1.38 (1.15-1.67), 1.51 (1.16-1.98) and 1.30 (1.03-1.64), respectively, for the composite endpoint, cardiovascular mortality and all-cause mortality. Further adjustment for left ventricular hypertrophy attenuated the relative risks, but they remained significant for cardiovascular mortality (1.45, 1.07-1.97) and for the composite endpoint (1.35, 1.11-1.66). After full adjustment, a prolonged QTcend-interval (> or =460 ms) conferred a 1.7-fold (1.1-2.6) higher risk of having a future fatal or nonfatal cardiovascular event. No other QT-interval component added further prognostic information to QTcend-interval duration.

CONCLUSIONS

Prolonged ventricular repolarization is a risk marker for cardiovascular morbidity and mortality in patients with resistant hypertension, over and beyond traditional cardiovascular risk factors, including ambulatory blood pressure and left ventricular hypertrophy.

Spironolactone and doxazosin treatment in patients with resistant hypertension

INTRODUCTION AND OBJECTIVES

The aim of this study was to evaluate the use of spironolactone and doxazosin as treatment for patients with resistant hypertension.

METHODS

This retrospective study involved 181 outpatients with resistant hypertension (defined as a failure of blood pressure [BP] control despite treatment with three drugs, one of which was a diuretic) who received additional spironolactone (n=88) or doxazosin (n=93).

RESULTS

Mean systolic BP in the spironolactone group fell by 28 mmHg (95% confidence interval [CI], 24-32 mmHg; P< .001) and mean diastolic BP fell by 12 mmHg (95% CI, 9-14 mmHg; P< .001). The corresponding falls in the doxazosin group were 16 mmHg (95% CI, 13-20 mmHg; P< .001) and 7 mmHg (95% CI, 5-9 mmHg; P< .001), respectively. The decrease was significantly greater with spironolactone for both systolic (P< .001) and diastolic (P=.003) pressures. At the end of follow-up, 30% of all patients had achieved BP control, with control being more frequent with spironolactone (39%) than doxazosin (23%; P=.02). Multivariate logistic regression analysis showed that the only factors that significantly influenced the achievement of BP control were diabetes (odds ratio=0.17; 95% CI, 0.08-0.39; P< .001) and baseline systolic BP <165 mmHg (odds ratio=2.56; 95% CI, 1.11-5.90; P=.03).

CONCLUSIONS

In patients with resistant hypertension, the addition of either spironolactone or doxazosin resulted in a significant decrease in BP, though the decrease appeared to be greater with spironolactone. The presence of diabetes complicated BP control.

Resistant hypertension: an overview of evaluation and treatment

Resistant hypertension is defined as failure to achieve goal blood pressure (BP) when a patient adheres to the maximum tolerated doses of 3 antihypertensive drugs including a diuretic. Although the exact prevalence of resistant hypertension is currently unknown, indirect evidence from population studies and clinical trials suggests that it is a relatively common clinical problem. The prevalence of resistant hypertension is projected to increase, owing to the aging population and increasing trends in obesity, sleep apnea, and chronic kidney disease. Management of resistant hypertension must begin with a careful evaluation of the patient to confirm the diagnosis and exclude factors associated with "pseudo-resistance," such as improper BP measurement technique, the white-coat effect, and poor patient adherence to life-style and/or antihypertensive medications. Education and reinforcement of life-style issues that affect BP, such as sodium restriction, reduction of alcohol intake, and weight loss if obese, are critical in treating resistant hypertension. Exclusion of preparations that contribute to true BP treatment resistance, such as nonsteroidal anti-inflammatory agents, cold preparations, and certain herbs, is also important. Lastly, BP control can only be achieved if an antihypertensive treatment regimen is used that focuses on the genesis of the hypertension. An example is volume overload, a common but unappreciated cause of treatment resistance. Use of the appropriate dose and type of diuretic provides a solution to overcome treatment resistance in this instance.

Cuff inflation during ambulatory blood pressure monitoring and heart rate

Introduction:

Twenty four-hour ambulatory blood pressure monitoring is a clinically validated procedure in evaluation of blood pressure (BP). We hypothesised that the discomfort during cuff inflation would increase the heart rate (HR) measured with 24-h ambulatory BP monitoring compared to a following HR measurement with a 24-h Holter monitor.

Methods:

The study population (n = 56) were recruited from the outpatient’s clinic at the Department of Nephrology, Aalborg Hospital, Aarhus University Hospital at Aalborg, Denmark. All the patients had chronic kidney disease (CKD). We compared HR measured with a 24-h Holter monitor with a following HR measured by a 24-h ambulatory BP monitoring.

Results:

We found a highly significant correlation between the HR measured with the Holter monitor and HR measured with 24-h ambulatory blood pressure monitoring (r = 0.77, p < 0.001). Using the Bland-Altman plot, the mean difference in HR was only 0.5 beat/min during 24 hours with acceptable limits of agreement for both high and low HR levels. Dividing the patients into groups according to betablocker treatment, body mass index, age, sex, angiotensin-converting enzyme inhibitor treatment, statins treatment, diuretic treatment, or calcium channel blocker treatment revealed similar results as described above.

Conclusion:

The results indicate that the discomfort induced by cuff inflation during 24-h ambulatory BP monitoring does not increase HR. Thus, 24-h ambulatory BP monitoring may be a reliable measurement of the BP among people with CKD.

Ambulatory arterial stiffness index or pulse pressure: which correlates better with arterial stiffness in resistant hypertension?

The ambulatory arterial stiffness index (AASI) is a recently proposed index derived from 24-h ambulatory blood pressure monitoring (ABPM) for the evaluation of arterial stiffness. In this cross-sectional study we investigated whether AASI reflects arterial stiffness in patients with resistant hypertension by comparing AASI and ambulatory pulse pressure (PP) with aortic pulse wave velocity (PWV), a measure of arterial stiffness, in 391 resistant hypertensives. Clinical, laboratory and echocardiographic variables, 24-h ABPM and aortic PWV (measured using the Complior device) were obtained. AASI was calculated as 1--the regression slope of 24-h diastolic on systolic blood pressure (BP). Statistical analysis involved single and multiple linear regressions to assess the correlations between the two ABPM variables and PWV, both unadjusted and adjusted for potential confounders (age, gender, body height, presence of diabetes, 24-h mean arterial pressure [MAP], heart rate, and nocturnal BP reduction). Ambulatory PP and aortic PWV were independently associated with age, gender, presence of diabetes, and 24-h MAP, whereas AASI was associated with age, diabetes, and nocturnal diastolic BP reduction. PP showed stronger unadjusted (r=0.39, p<0.001) and adjusted (r=0.22, p<0.001) correlations with aortic PWV than AASI (r=0.12, p=0.032 and r= -0.04, p=0.47, respectively). In the analysis of subgroups stratified by gender, age, presence of atherosclerotic diseases and diabetes, dipping pattern, and ambulatory BP control, the superiority of PP over AASI was apparent in all subgroups. In conclusion, 24-h ambulatory PP was better correlated to arterial stiffness, as evaluated by aortic PWV, than the novel AASI, in patients with resistant hypertension.

Relating cardiovascular risk to out-of-office blood pressure and the importance of controlling blood pressure 24 hours a day

Blood pressure exhibits a natural circadian rhythm characterized by a decrease during sleep, then a steep increase in the early morning period followed by higher values throughout the active waking period. Because an excessive early morning surge in blood pressure is associated with an elevated risk for cardiovascular events, it represents a potential therapeutic target in patients with hypertension, especially those already at high risk for such events. Ambulatory blood pressure monitoring (ABPM) is an out-of-office technique that allows assessment of blood pressure control during a 24-hour period, including the morning surge. It is known that 24-hour control based on ABPM is a better predictor of hypertensive target-organ involvement and cardiovascular events than conventional in-office blood pressure measurement. ABPM also reveals that many antihypertensive drugs do not adequately control early morning blood pressure, particularly when given once daily in the morning. There are several effective ways to improve morning blood pressure control. These include using agents with a long pharmacologic half-life; prescribing drug formulations specifically designed to target the morning blood pressure surge when given at bedtime; or increasing dosages to twice daily that of conventional shorter-acting agents.

Pulse pressure or dipping pattern: which one is a better cardiovascular risk marker in resistant hypertension?

OBJECTIVE

Nocturnal blood pressure (BP) reduction and ambulatory pulse pressure (PP) are well known prognostic markers obtained from ambulatory BP monitoring (ABPM). The aim of this study is to investigate which one of these ABPM parameters is related to high cardiovascular risk profile in resistant hypertension, based on their associations with target organ damage (TOD).

METHODS

Clinical-demographic, laboratory and ABPM variables were recorded in a cross-sectional study involving 907 resistant hypertensive patients. Nocturnal systolic BP reduction and 24-h PP were assessed both as continuous and dichotomized variables (PP at the upper tertile value: 63 mmHg). Statistical analyses included bivariate tests and multivariate logistic regression with each TOD as the dependent variable.

RESULTS

Patients with the nondipping pattern and high 24-h PP shared some characteristics: they were older, had higher prevalence of cerebrovascular disease and nephropathy, higher office and 24-h BP levels, increased serum creatinine and microalbuminuria, and higher left ventricular mass index than their counterparts. Additionally, patients with high PP had a greater prevalence of diabetes and other TOD. In multivariate logistic regression, high PP was independently associated with all TODs even after adjustment for sex, age, BMI, cardiovascular risk factors, 24-h mean arterial pressure and antihypertensive treatment, whereas nondipping pattern was only associated with hypertensive nephropathy. Furthermore, PP was more strongly associated with the number of TOD than the nocturnal systolic blood pressure (SBP) fall.

CONCLUSIONS

In a large group of resistant hypertensive patients, an increased 24-h PP shows a closer correlation with high cardiovascular risk profile than the nocturnal BP reduction.

Predicting arterial stiffness with ambulatory blood pressure: an 11-year follow-up

No prospective data have been published on whether ambulatory blood pressure (BP) works better than casual measurements in predicting arterial stiffness. This study with 11-year follow-up was launched to evaluate the usefulness of ambulatory intra-arterial BP in predicting pulse wave velocity (PWV). Ninety-seven previously healthy men were recruited from a routine physical check-up at baseline. BP was measured with standard cuff and intra-arterial ambulatory methods. Sixty-seven subjects with no antihypertensive medication were enrolled for a visit after a follow-up of 11 years. Arterial stiffness was estimated with PWV derived with impedance cardiography. Ambulatory 24-h systolic blood pressure (SBP) (r = 0.30, P = 0.01), 24-h mean arterial pressure (r = 0.27, P = 0.03), 24-h pulse pressure (r = 0.27, P = 0.03) and daytime SBP (r = 0.26, P = 0.03) were the best BP variables in predicting future PWV. Casual BP values did not bear significant correlations with future PWV. In hierarchical regression analysis, the best predictive value for future PWV was achieved with the model including ambulatory 24-h SBP, smoking (number of cigarettes) and age (adjusted R(2) = 0.26). In conclusion, to our knowledge, this is the only prospective follow-up study to show that ambulatory BP is superior to casual BP measurement in predicting future PWV.

Masked hypertension definition, impact, outcomes: a critical review

The phenomenon of masked hypertension (MH) is defined as a clinical condition in which a patient's office blood pressure (BP) level is <140/90 mm Hg but ambulatory or home BP readings are in the hypertensive range. The prevalence in the population is about the same as that of isolated office hypertension; about 1 in 7 or 8 persons with a normal office BP level may fall into this category. The high prevalence of MH would suggest the necessity for measuring out-of-office BP in persons with apparently normal or well-controlled office BP. Reactivity to daily life stressors and behavioral factors such as smoking, alcohol use, contraceptive use in women, and sedentary habits can selectively influence MH. MH should be searched for in individuals who are at increased risk for cardiovascular complications including patients with kidney disease or diabetes. Individuals with MH have been shown to have a greater-than-normal prevalence of organ damage, particularly with an increased prevalence of metabolic risk factors, left ventricular mass index, carotid intima-media thickness, and impaired large artery distensibility compared with patients with a truly normal BP level in and out of the clinic or office. Also, outcome studies have suggested that MH increases cardiovascular risk, which appears to be close to that of in-office and out-of-office hypertension. The aim of this review was to define the entity of MH, to describe its prevalence in the general population, and to discuss its correlation with cardiovascular events.

Incidence of cardiovascular events in white-coat, masked and sustained hypertension versus true normotension: a meta-analysis

OBJECTIVE

To perform a meta-analysis on the incidence of cardiovascular events in white-coat hypertension (WCHT), masked and sustained hypertension in comparison with true normotension.

METHODS

We searched for individual studies, in which the adjusted relative risk of incident cardiovascular events was assessed in patients with WCHT, masked and sustained hypertension versus normotension in the same study population. For each type of hypertension, the weighted overall hazard ratio (HR) and 95% confidence intervals (CI) were calculated.

RESULTS

Seven studies were identified, involving a total of 11 502 participants. Four studies were performed in the population, two in primary care and one in specialist care. Two studies were exclusively on treated hypertensive patients; individuals on antihypertensive treatment were included in all the other studies except one. Cut-off blood pressure was 140/90 mmHg for office blood pressure in all studies and 135/85 mmHg (83 in one study) for out-of-office blood pressure. The average age of the study populations was 63 years; 53% were men. The endpoint consisted of cardiovascular death in one study and of various aggregates of fatal and non-fatal cardiovascular events in the others. During an average follow-up of 8.0 years, there were 912 first cardiovascular events. The overall adjusted HR versus normotension was 1.12 (95% CI 0.84-1.50) for WCHT (P = 0.59), 2.00 (1.58-2.52) for masked hypertension (P < 0.001), and 2.28 (1.87-2.78) for sustained hypertension (P < 0.001).

CONCLUSION

The meta-analysis indicates that the incidence of cardiovascular events is not significantly different between WCHT and true normotension, whereas the outcome is worse in patients with masked or sustained hypertension.

Aldosterone excess and resistance to 24-h blood pressure control

BACKGROUND

Aldosterone excess has been reported to be a common cause of resistant hypertension. To what degree this represents true treatment resistance is unknown.

OBJECTIVE

The present study aimed to compare the 24-h ambulatory blood pressure monitoring (ABPM) levels in resistant hypertensive patients with or without hyperaldosteronism.

METHODS

Two hundred and fifty-one patients with resistant hypertension were prospectively evaluated with an early-morning plasma renin activity (PRA), 24-h urinary aldosterone and sodium, and 24-h ABPM. Daytime, night-time, and 24-h blood pressure (BP) and nocturnal BP decline were determined. Hyperaldosteronism (H-Aldo) was defined as suppressed PRA (<1.0 ng/ml per h or <1.0 mug/l per h) and elevated 24-h urinary aldosterone excretion (>/= 12 mug/24-h or >/= 33.2 nmol/day) during ingestion of the patient's routine diet.

RESULTS

In all patients, the mean office BP was 160.0 +/- 25.2/89.4 +/- 15.3 mmHg on an average of 4.2 medications. There was no difference in mean office BP between H-Aldo and normal aldosterone status (N-Aldo) patients. Daytime, night-time, and 24-h systolic and diastolic BP were significantly higher in H-Aldo compared to N-Aldo males. Daytime, night-time, and 24-h systolic BP were significantly higher in H-Aldo compared to N-Aldo females. Multivariate analysis indicated a significant interaction between age and aldosterone status such that the effects of aldosterone on ambulatory BP levels were more pronounced with increasing age.

CONCLUSIONS

In spite of similar office BP, ABPM levels were higher in resistant hypertensive patients with H-Aldo. These results suggest that high aldosterone levels impart increased cardiovascular risk not reflected by office BP measurements.

Prognostic superiority of daytime ambulatory over conventional blood pressure in four populations: a meta-analysis of 7,030 individuals

OBJECTIVE

To investigate the multivariate-adjusted predictive value of systolic and diastolic blood pressures on conventional (CBP) and daytime (10-20 h) ambulatory (ABP) measurement.

METHODS

We randomly recruited 7,030 subjects (mean age 56.2 years; 44.8% women) from populations in Belgium, Denmark, Japan and Sweden. We constructed the International Database on Ambulatory blood pressure and Cardiovascular Outcomes.

RESULTS

During follow-up (median = 9.5 years), 932 subjects died. Neither CBP nor ABP predicted total mortality, of which 60.9% was due to noncardiovascular causes. The incidence of fatal combined with nonfatal cardiovascular events amounted to 863 (228 deaths, 326 strokes and 309 cardiac events). In multivariate-adjusted continuous analyses, both CBP and ABP predicted cardiovascular, cerebrovascular, cardiac and coronary events. However, in fully-adjusted models, including both CBP and ABP, CBP lost its predictive value (P >or= 0.052), whereas systolic and diastolic ABP retained their prognostic significance (P <or= 0.007) with the exception of diastolic ABP as predictor of cardiac and coronary events (P >or= 0.21). In adjusted categorical analyses, normotension was the referent group (CBP < 140/90 mmHg and ABP < 135/85 mmHg). Adjusted hazard ratios for all cardiovascular events were 1.22 [95% confidence interval (CI) = 0.96-1.53; P = 0.09] for white-coat hypertension (>or= 140/90 and < 135/85 mmHg); 1.62 (95% CI = 1.35-1.96; P < 0.0001) for masked hypertension (< 140/90 and >or= 135/85 mmHg); and 1.80 (95% CI = 1.59-2.03; P < 0.0001) for sustained hypertension (>or= 140/90 and >or= 135/85 mmHg).

CONCLUSIONS

ABP is superior to CBP in predicting cardiovascular events, but not total and noncardiovascular mortality. Cardiovascular risk gradually increases from normotension over white-coat and masked hypertension to sustained hypertension.

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.

Essential hypertension

Essential hypertension can be defined as a rise in blood pressure of unknown cause that increases risk for cerebral, cardiac, and renal events. In industrialised countries, the risk of becoming hypertensive (blood pressure >140/90 mm Hg) during a lifetime exceeds 90%. Essential hypertension usually clusters with other cardiovascular risk factors such as ageing, being overweight, insulin resistance, diabetes, and hyperlipidaemia. Subtle target-organ damage such as left-ventricular hypertrophy, microalbuminuria, and cognitive dysfunction takes place early in the course of hypertensive cardiovascular disease, although catastrophic events such as stroke, heart attack, renal failure, and dementia usually happen after long periods of uncontrolled hypertension only. All antihypertensive drugs lower blood pressure (by definition) and this decline is the best determinant of cardiovascular risk reduction. However, differences between drugs exist with respect to reduction of target-organ disease and prevention of major cardiovascular events. Most hypertensive patients need two or more drugs for blood-pressure control and concomitant statin treatment for risk factor reduction. Despite the availability of effective and safe antihypertensive drugs, hypertension and its concomitant risk factors remain uncontrolled in most patients.

Do we need out-of-office blood pressure in every patient?

PURPOSE OF REVIEW

The limitations affecting office blood pressure readings have spurred the development of techniques for measuring blood pressure out of a clinical environment. The increasing use of home and ambulatory blood pressure monitoring has allowed the identification of specific blood pressure patterns related either to a discrepancy between office and out-of-office blood pressure or to alterations in the 24-h blood pressure profiles. This review offers an update on the most recent data published on the above issues.

RECENT FINDINGS

A critical overview is provided on recent data published on blood pressure patterns suggested to have clinical relevance. These include white coat hypertension, the so-called masked hypertension, enhanced overall blood pressure variability over 24 h, a steeper morning blood pressure surge and a blunted or an excessive blood pressure fall at night.

SUMMARY

All of these different conditions have been variably reported to carry prognostic implications, and may represent specific targets for antihypertensive treatment. Their identification and management require information on out-of-office blood pressure, which suggests that self blood pressure monitoring at home or 24-h ambulatory blood pressure monitoring should be used more frequently in clinical practice, following the indications issued in recent guidelines.

Systemic hypertension

Hypertension is a growing public health problem worldwide. Only 37% of American hypertensives currently have their blood pressures controlled. Hypertension is traditionally diagnosed in the medical office, but both home and ambulatory blood pressure monitoring can help. Lifestyle modifications are recommended for everyone who has higher than "normal" blood pressure (<120/80 mm Hg). Voluminous clinical trial data support beginning drug therapy with low-dose chlorthalidone, unless the patient has a specific indication for a different drug. Additional drugs (typically in the sequence, angiotensin converting-enzyme inhibitor or angiotensin receptor blocker, calcium antagonist, beta-blocker, alpha-blocker, aldosterone antagonist, direct vasodilator, and centrally acting alpha(2)-agonist) can be added to achieve the blood pressure goal (usually <140/90 mm Hg, but <130/80 mm Hg for diabetics and those with chronic kidney disease). Special circumstances exist for treatment of hypertension in pregnancy, in childhood, in the elderly, and in both extremes of blood pressure (pre-hypertension or hypertensive emergencies).

Ambulatory blood pressure monitoring in hypertensive patients with high cardiovascular risk: a cross-sectional analysis of a 20 000-patient database in Spain

OBJECTIVE

To evaluate ambulatory blood pressure monitoring (ABPM) parameters in a broad sample of high-risk hypertensive patients.

METHODS

The Spanish Society of Hypertension is developing a nationwide project in which more than 900 physicians send ABPM registries and corresponding clinical records to a central database via www.cardiorisc.com. Between June 2004 and July 2005 a 20 000-patient database was obtained; 17 219 were valid for analysis.

RESULTS

We identified 6534 patients with high cardiovascular risk according to the 2003 European Society of Hypertension/European Society of Cardiology guidelines stratification score. Office blood pressure (BP) was 158.8/89.9 mmHg and 24-h BP was 135.8/77.0 mmHg. Patients with grade 3 BP in the office showed ambulatory systolic BP values less than 160 mmHg in more than 80%. A non-dipping pattern was observed in 3836 cases (58.7%), whereas this abnormality was present in 47.9% of patients with low-to-moderate risk [odds ratio (OR) 1.54; 95% confidence interval (CI) 1.45-1.64]. The prevalence of non-dippers was higher as ambulatory BP increased ( approximately 70% when 24-h systolic BP > 155 mmHg) and was similar in both groups. At the lowest levels of BP (24-h systolic BP < 135 mmHg) a non-dipping pattern was more prevalent in high-risk cases (56.6 versus 45.7%; OR 1.51; 95% CI 1.40-1.64).

CONCLUSION

There was a remarkable discrepancy between office and ambulatory BP in high-risk hypertensive patients. The prevalence of a non-dipper BP pattern was almost 60%. In the lowest levels of ambulatory BP, high-risk patients showed a higher prevalence of non-dipping BP than lower-risk cases. These observations support the recommendation of a wider use of ABPM in high-risk hypertensive patients.

Clinical characteristics of resistant hypertension: the importance of compliance and the role of diagnostic evaluation in delineating pathogenesis

Resistant hypertension is defined as failure to achieve goal blood pressure despite adherence to 3 different antihypertensive medications, one of which must be a diuretic. True resistant hypertension must be distinguished by apparent resistant hypertension, of which an important cause is medication nonadherence, which can be recognized through a variety of monitoring strategies and may be improved through better patient education. A thorough history and examination should focus on evaluating for associated factors such as medication and illicit drug use, alcoholism, obesity, and obstructive sleep apnea. Further evaluation to differentiate apparent resistant hypertension from true resistant hypertension should include consideration of ambulatory blood pressure monitoring to rule out white coat hypertension. Routine laboratory work will reveal chronic kidney disease, which is the most common associated factor in resistant hypertension. Secondary or identifiable causes of resistant hypertension include primary aldosteronism, renovascular disease, and pheochromocytoma. Diagnostic evaluation for identifiable causes should be tailored for each patient and guided by signs and symptoms, as well as risks and benefits.

Ambulatory blood pressure monitoring: what a pediatrician should know

PURPOSE OF REVIEW

Ambulatory blood pressure monitoring is a useful tool for the evaluation and management of hypertension in children and adolescents. This review provides a basic overview of ambulatory blood pressure monitoring and summarizes the most recent available knowledge regarding its use in the pediatric population.

RECENT FINDINGS

Evaluation and validation of ambulatory blood pressure monitoring equipment in children remains limited, although advances in the interpretation of results for this age group have been reported specifically in the area of circadian (24 h) and ultradian (<24 h) variability. Blood pressure is a dynamic phenomenon that varies not only with time but also with changing patient and environmental circumstances. Growing evidence regarding conditions identified when this variability is considered, specifically white coat and masked hypertension, suggests that office blood pressure measurement may not be a sufficient screening test for hypertension-related target-organ damage.

SUMMARY

Information regarding ambulatory blood pressure monitoring use in children is increasing, although due to its limitations and expense, it remains a tool primarily utilized by the pediatric sub-specialist.

Association of clinic and ambulatory blood pressure with vascular damage in the elderly: the EPICARDIAN study

OBJECTIVES

In middle-aged adults, vascular damage correlates better with ambulatory than with clinic blood pressure. This study aimed to determine whether vascular damage evaluated by carotid ultrasonography in the elderly is also more closely related to ambulatory than to clinic blood pressure, and which blood pressure variables are better associated with vascular damage.

METHODS

Cross-sectional study of 292 randomly selected >65 years old participants who underwent 24-h noninvasive ambulatory blood pressure monitoring. Blood pressure variables analyzed were (a) clinic blood pressure: systolic and diastolic blood pressure, pulse pressure; (b) ambulatory blood pressure monitoring: mean values of systolic and diastolic blood pressure, systolic and diastolic blood pressure load, pulse pressure, as well as variability, evaluated within 24 h, diurnal and nocturnal periods; and day-night blood pressure difference. A clinical history, physical examination, carotid ultrasonography and laboratory tests were performed. To estimate the relationship between blood pressure and vascular damage, univariate and multivariate analyses were performed.

RESULTS

Mean age: 73+/-6 years, 45% men, 76.7% hypertensive patients. In the simple regression analysis, the best significant correlations (P<0.05) were common carotid intima-media thickness with 24-h and nocturnal pulse pressure (r=0.32), and common carotid diameter with 24-h systolic blood pressure load (r=0.47). In the multivariate analysis, the significant associations (P<0.05) were (a) linear regression: nocturnal pulse pressure with common carotid intima-media thickness, and diurnal pulse pressure as well as 24-h systolic blood pressure load with common carotid diameter; (b) logistic regression, adjusted odds ratio: nocturnal pulse pressure and nocturnal diastolic blood pressure load with the presence of carotid atherosclerotic plaques 1.03 and 0.98, respectively.

CONCLUSIONS

In the elderly, ambulatory blood pressure monitoring is better associated with carotid damage than clinic blood pressure. Systolic blood pressure variables are the best associated, blood pressure load and pulse pressure being better associated with carotid damage than the mean levels of ambulatory blood pressure.

Resistant or Difficult‐to‐Treat Hypertension

Resistant hypertension, defined as uncontrolled hypertension on three medications, is becoming an increasingly common problem. In most cases, blood pressure remains elevated because of persistently high systolic blood pressure levels. Common characteristics of patients with resistant hypertension include older age, obesity, excessive dietary salt ingestion, and presence of sleep apnea. The evaluation of patients with resistant hypertension is focused on identifying contributing and secondary causes of hypertension. Treatment should include both lifestyle changes (weight loss, exercise, dietary salt restriction) and the use of effective multidrug regimens, including a diuretic. Recent data indicate that aldosterone antagonists may be effective when added to existing antihypertensive regimens even in the absence of primary aldosteronism.