Physical activity level is an independent predictor of the diurnal variation in blood pressure

OBJECTIVE: The aim of this study was to define the relationship between physical activity and the magnitude of the percentage fall in blood pressure at night (nocturnal dip). METHODS: We simultaneously monitored 24-h ambulatory blood pressure and measured physical activity by actigraphy in 434 patients. Blood pressure was measured every 20 min; the actigraph integrated an activity score every 10 s. Mean daytime and night-time activity were calculated from mean scores for the 15 min preceding each blood pressure measurement. Nocturnal dip in systolic and diastolic blood pressure (SBP and DBP) were regressed on mean (log-transformed) daytime activity. Mean night-time activity, age, gender, smoking status, body mass index (BMI) and clinic blood pressure were added into a multiple linear regression. RESULTS: The patient group was heterogeneous in age, gender and mean 24-h blood pressure. Mean daytime activity level was significantly and positively associated with the magnitude of the nocturnal dip in both SBP and DBP. Increased night-time activity was significantly associated with a smaller nocturnal dip. Older patients had a smaller nocturnal dip per log unit daytime activity. Nocturnal dip in SBP was greater in males, and smaller in those taking antihypertensive medications. Smoking, BMI and clinical blood pressure level were not associated with the extent of the nocturnal dip after adjustment for other factors. CONCLUSIONS: Daytime and night-time physical activity levels are independently and significantly predictive of the magnitude of the nocturnal dip in blood pressure. Variation in activity may confound interpretation of 24-h ambulatory blood pressure monitoring, and contribute to the poor reproducibility of dipper status.     

The white-coat effect is associated with increased blood pressure reactivity to physical activity

OBJECTIVE: The aim of this study was to test the hypothesis that blood pressure (BP) reactivity to the stress of a clinic visit, the so-called white-coat effect, is associated with increased BP reactivity to physical activity. DESIGN: Patients referred to our clinic for assessment of hypertension prospectively underwent 24-h ambulatory BP monitoring and simultaneous actigraphy. METHODS: The difference between mean clinic BP and mean daytime ambulatory BP was considered to be a measure of the white-coat effect. Presence or absence of a white-coat effect (clinic-daytime difference > 0 mmHg) was added to a mixed model regression of BP on mean activity score for the 10-min interval preceding BP measurement. RESULTS: The group (n = 421) was heterogeneous in age, gender, mean 24-h BP and use of antihypertensive medications. A total of 259 patients had a systolic white-coat effect; for diastolic BP there were 264. Female patients exhibited a significantly larger white-coat effect. Coefficients for the regressions of both systolic and diastolic blood pressure on physical activity levels were significantly higher in those who had a white-coat effect. CONCLUSIONS: These data suggest increased BP reactivity to activity in those with a white-coat effect. Patients with a prominent white-coat effect may experience greater BP load during normal daily activities as a consequence of increased BP reactivity. In patients with white-coat hypertension, this may contribute to target-organ damage.     

Chronobiological analysis by ambulatory blood pressure monitoring of the hyperbaric and hypobaric indexes for evaluation of the antihypertensive effect of long-acting nifedipine.

BACKGROUND: It has been suggested that chronobiology can provide new insights into the evaluation and treatment of cardiovascular disease. In the present study the hyperbaric index (hyperBI) and hypobaric index (hypoBI) were compared with the mean blood pressure (BP) over 24 h to evaluate the antihypertensive effect of long-acting nifedipine on essential hypertension. METHODS AND RESULTS: Fourteen patients were treated with nifedipine CR (20-40 mg/day) for 6 months. Ambulatory BP monitoring was performed before and after treatment. The hyperBI (mmHg . h/day) was calculated as the integrated BP area above the conventional upper limit (140/90 mmHg for the daytime and 120/80 mmHg at night), and the hypoBI was calculated as the integrated BP area below the conventional lower limit (110/60 mmHg for the daytime and 100/50 mmHg at night). At baseline, both the systolic and diastolic 24-h hyperBI values closely correlated with the 24-h mean BP (r=0.994 and 0.935, p<0.0001). Treatment with nifedipine significantly lowered both the 24-h mean systolic and diastolic BP (143+/-14/89 +/-12 to 124+/-16/80+/-8 mmHg, p<0.001/p=0.001), as well as the casual BP (167+/-11/101 +/-8 to 140+/-13/86+/-10 mmHg, p<0.001/p<0.01). Reduction of both the systolic and diastolic hyperBI values was statistically significant over the 24-h period (274+/-266 to 90+/-155, p=0.009; 145+/-187 to 41+/-63, p=0.024), as well as during the daytime (200+/-181 to 66+/-116, p=0.014; 105+/-120 to 24+/-38, p=0.017) and at night (systolic, 74+/-106 to 24+/-52, p=0.021). The 24-h mean BP was normalized, but a small excess BP load persisted despite treatment. There was no significant increase of systolic hypoBI during the 24-h period (1+/-2 to 25+/-30, p=0.065), the daytime (0+/-0 to 14+/-38, p=0.20), or at night (1+/-3 to 11+/-19, p=0,052). Similar findings were obtained for diastolic hypoBI. CONCLUSIONS: Nifedipine CR improved the 24-h hyperBI and mean BP without causing excessive hypotension. These 2 parameters have a close relationship when assessment is done by 24-h BP monitoring. The hyperBI and hypoBI may assist in providing adequate antihypertensive therapy for individual patients by detecting an excessive BP load or hypotension, respectively.     

Effect of quinapril on blood pressure and heart rate in congestive heart failure.

The effect of quinapril on blood pressure (BP), heart rate (HR) and their variabilities in 12 patients with severe congestive heart failure (New York Heart Association class III and IV) was assessed using ambulatory electrocardiographic and intraarterial monitoring. Mean +/- standard deviation daytime BP was 122/75 +/- 20/15 mm Hg at baseline and 113/70 +/- 13/16 mm Hg after 16 weeks of therapy with quinapril (p greater than 0.05 for systolic and diastolic BP); mean nighttime BP was 114/69 +/- 19/14 mm Hg at baseline and 107/69 +/- 15/14 mm Hg with quinapril (p greater than 0.05 for systolic and diastolic BP). Mean daytime HR was unchanged but nighttime HR was reduced from 77 +/- 11 to 71 +/- 10 beats/min, p = 0.02. HR variability (difference between the 75th and 25th percentiles of the frequency distribution of RR intervals) increased from 91 +/- 34 to 134 +/- 47 ms, p = 0.008. The variability of successive differences between RR intervals also increased significantly (75th to 25th percentile = 17 +/- 4 ms at baseline and 31 +/- 26 ms with quinapril, p = 0.02). Long-term quinapril caused clinically unimportant decreases in BP in patients with severe congestive heart failure. An increase in vagal activity caused by the reduction in circulating angiotensin II may account for the effect of converting enzyme inhibition on HR and its variability.     

Blood pressure variability in children with essential hypertension

The aim of this study was to assess blood pressure variability (BPV) and its determinants in untreated hypertensive children. The study group consisted of 124 children, 91 boys and 33 girls, aged 14.9+/-2.5 with essential hypertension and no use of antihypertensive drugs. The subjects underwent routine examination, blood tests and ambulatory blood pressure (BP) monitoring. BPV was defined as the value of the standard deviation of BP for day- and night time periods. Daytime BPV was higher than night time BPV, and systolic BPV was higher than diastolic BPV. Significant positive correlations between 24-h, day- and night time systolic blood pressure (SBP), but not for diastolic blood pressure (DBP), and BPV were observed. In univariate analysis, day- and night time systolic BPVs were correlated with fasting glucose (r=0.609, P=0.02 and r=0.439, P=0.04); daytime systolic BPV, daytime diastolic BPV and night time systolic BPV were correlated with birth length (r=0.428, P=0.04; r=0.426, P=0.04 and r=0.439, P=0.04, respectively), and night time systolic BPV and night time diastolic BPV were correlated with age (r=0.604, P=0.02 and r=0.833, P=0.0001). However, in multiple linear regression analysis, daytime diastolic BPV was determined only by gender and systolic 24-h BP; night time systolic BPV depended on age, daytime SBP and DBP values, and daytime SBP and DBPs were determinants of night time diastolic BPV. The results highlighted the complex nature of BPV, with favourable role of host factors in its aetiology. The determinants of BPV in children are consistent with those in adults. Relationships between BPV and its determinants in untreated hypertensive subjects ought to be investigated in further researches.     

Changes in home versus clinic blood pressure with antihypertensive treatments: a meta-analysis

Home blood pressure (HBP) monitoring is recommended for assessing the effects of antihypertensive treatment, but it is not clear how the treatment-induced changes in HBP compare with the changes in clinic blood pressure (CBP). We searched PubMed using the terms "home or self-measured blood pressure," and selected articles in which the changes in CBP and HBP (using the upper arm oscillometric method) induced by antihypertensive drugs were presented. We performed a systematic review of 30 articles published before March 2008 that included a total of 6794 subjects. As there was significant heterogeneity in most of the outcomes, a random effects model was used for the meta-analyses. The mean changes (+/-SE) in CBP and HBP (systolic/diastolic) were -15.2+/-0.03/-10.3+/-0.03 mm Hg and -12.2+/-0.04/-8.0+/-0.04 mm Hg respectively, although there were wide varieties of differences in the reduction between HBP and CBP. The reductions in CBP were correlated with those of HBP (systolic BP; r=0.66, B=0.48, diastolic BP; r=0.71, B=0.52, P<0.001). In 7 studies that also included 24-hour BP monitoring, the reduction of HBP was greater than that of 24-hour BP in systolic (HBP; -12.6+/-0.06 mm Hg, 24-hour BP; -11.9+/-0.04 mm Hg, P<0.001). In 5 studies that included daytime and nighttime systolic BP separately, HBP decreased 15% more than daytime ambulatory BP and 30% more than nighttime ambulatory BP. In conclusion, HBP falls approximately 20% less than CBP with antihypertensive treatments. Daytime systolic BP falls 15% less and nighttime systolic BP falls 30% less than home systolic BP.     

Study of representative periods of day-time and night-time levels of blood pressure

The aim of this study is to assess whether it is possible to shorten ambulatory blood pressure (ABP) monitoring while getting measurements that precisely reflect 24 hours and daytime blood pressure (BP). METHODS: three hundred and thirty six young male subjects aged: 21 +/- 2 y, height: 178 +/- 7 cm, weight, 75 +/- 12 kg, with normal or "borderline" BP (casual BP: 138 +/- 13/79 +/- 8 mmHg) participated in the study. BP was recorded in each, every 15 minutes on 24 hours with a Spacelabs 5200 device. Systolic and diastolic BP on 24-h, during the 9 a.m. - 8 p.m. period (daytime) and BP related to the different subperiods included between 15 minutes and 6 hours were calculated. BP values obtained from the 196 subperiods were correlated with 24-h, daytime ABP and causal BP. Results were classified according to the value of correlation coefficient, slope and intercept of regressions. RESULTS: no subperiod accurately predict 24-h systolic BP (SBP) or diastolic BP (DBP) (the best correlation are established with the subperiods: 7 p.m.-01 a.m. for SBP; r = 0.916, p less than 10(-9), y = 0.76 x + 30; and 06 a.m.-12 a.m. for DBP; r = 0.914, p less than 10(-9), y = 0.87 x + 9). Four 6 hours subperiods sampled between 09 a.m.-3 p.m. and 12 a.m.-6 p.m. predict alike and in a reasonable way the daytime BP (SBP: r = 0.971, p less than 10(-9), y = 0.94 x + 8; r = 0.973, p less than 10(-9), y = 0.91 x + 7. Best correlations with casual BP are moderate (SBP: r = 0.674, DBP: r = 0.588). COMMENTS: BP measurements of subperiods smaller or equal to 6 hours cannot accurately predict the average 24-h BP. This is related mainly to the night-time/daytime BP fluctuations. Daytime BP can be estimated with short-term monitoring but the duration must not be smaller than 6 hours.     

Baroreflex and blood pressure variations in borderline hypertension of the young adult

Blood pressure (BP) variability depends on external and internal factors. Among these, arterial baroreflex play an important role. The matter of this study is to assess the relationship between these two parameters in borderline hypertension (BL). Twenty six BL male hypertensive were recruited for the study, all gave informed consent. Age: 21 +/- 2 years, height: 177 +/- 8 cm, weight: 77 +/- 14 kg. An ambulatory BP monitoring was performed in each one using a Diasys (Novacor) recorder. Measurements were obtained each 15 minutes for 24 hours. Mean, standard deviation and variation coefficient (VC) of BP and heart rate (HR) were computed for 24 hours, daytime (9a.m.-7 p.m.), nighttime (11 p.m.-7 a.m.). Baroreflex sensitivity (BRS) was determined as the ratio of HR variation on systolic BP variation recorded with a Finapres device from the fourth phase of a Valsalva manoeuvre. Mean systolic and diastolic BP values for 24 hours, daytime and nighttime are: 129 +/- 11/73 +/- 13, 137 +/- 14/76 +/- 15, 114 +/- 11/69 +/- 12 mmHg. VC are: 12 +/- 3/15 +/- 3, 9 +/- 3/13 +/- 3, 10 +/- 3/13 +/- 4%. HR values are: 73 +/- 10, 84 +/- 14, 58 +/- 7 b/min, VC are: 24 +/- 5, 17 +/- 4, 17 +/- 7%. Index for BRS = 1.76 +/- 0.65%. There is no correlation between BRS and systolic BP or HR. BRS is correlated to the inverse of systolic daytime BP VC: r = -0.556, p = 0.003. There is no correlation with other parameters. This study provides evidence for a link between BRS and daytime BP variability in borderline hypertension.     

White coat effect in treated and untreated patients with high office blood pressure. Relationship with pulse wave velocity and left ventricular mass index.

OBJECTIVE: To evaluate in hypertensive patients whether the white coat effect is associated with target-organ damage and whether it is modified by anti-hypertensive therapy. METHODS: In a cross-sectional study we evaluated blood pressure (BP) measured in the office and by 24-h ambulatory blood pressure monitoring (ABPM), carotid-femoral pulse wave velocity (PWV) as an index of aortic stiffness, and left ventricular mass index (LVMI) in 88 subjects (aged 49 +/- 2 years) with white-coat hypertension (WCH, office BP > 140/90, daytime BP < 130/84 mmHg), 31 under antihypertensive therapy, 57 untreated, and in 115 patients with office and ambulatory hypertension (HT, aged 51 +/- 2 years, office BP > 140/90, daytime BP > 135/85), 65 under antihypertensive therapy, 50 untreated. In a longitudinal study in 15 patients with HT and in 11 patients with WCH we evaluated the influence of antihypertensive therapy (> 6 months) on office and ambulatory BP and on PWV. RESULTS: The intensity of the white coat effect (office BP-daytime BP) was greater in WCH than in HT. Taking all subjects, the white coat effect did not correlate with PWV (r = 0.08, ns) or with LVMI (r = 0.01, ns), whereas daytime BP correlated significantly with PWV (r = 0.41, p < 0.01) and with LVMI (r = 0.32, p < 0.05). WCH subjects showed lower PWV and LVMI than HT subjects. Treated and untreated WCH, with similar office and daytime BP, showed similar values of PWV and LVMI. Treated and untreated HT showed similar office BP values but treated HT showed lower daytime BP and PWV values. In the longitudinal study, antihypertensive therapy significantly reduced daytime BP and PWV values in the 15 HTs, whereas in the 11 WCH it did not alter daytime BP or PWV values. CONCLUSIONS: 1. In both WCH and HT (treated and untreated) the intensity of the white coat effect does not reflect either the severity of hypertension measured by target organ damage or the efficacy of antihypertensive treatment. 2. In WCH antihypertensive therapy does not improve either ambulatory BP values or damage to target organs.     

Determinants of ambulatory blood pressure response to physical activity

OBJECTIVES: Previous studies reported that the association between physical activity, measured with a wrist-worn accelerometer, and ambulatory blood pressure is rather weak and that the inter-individual variation in the degree of association is high. The aim of the present study was to quantify the responses of ambulatory blood pressure (BP) and heart rate (HR) to physical activity, and to determine the effect of age, gender, body mass index, mean BP and HR level and the use of antihypertensive medication on these responses. PATIENTS AND METHODS: Twenty-seven subjects (24 hypertensive) underwent 24-h ambulatory monitoring of BP, HR and physical activity. Physical activity was measured with four accelerometers mounted on the trunk and legs. The daytime BP and HR responses to physical activity and the possible modulating effects of the various subject characteristics on these responses were estimated with Random Regression Models. RESULTS: Increasing physical activity from a very low level (e.g. watching television) to a moderate level (e.g. shopping) caused an average response of systolic blood pressure (SBP) of 11.6 mmHg, of diastolic blood pressure (DBP) of 7.0 mmHg and of HR of 16.1 beats/min. The SBP response to activity was about 2 mmHg larger for the overweight subjects than for subjects with normal weight, and the SBP, DBP and HR responses increased about 0.8 mmHg, 0.6 mmHg and 0.7 beats/min, respectively, with every 10 years increase in age. The between-subjects variances in estimated responses were low and were almost completely explained by differences in overweight and age between subjects. The average within-subject variances, however, were high. CONCLUSIONS: Normal daily physical activity explains only a small part of the BP and HR variability. The BP and HR responses to activity are modestly affected by age. Overweight has a small effect on the SBP response to activity.     

Physical activity, dipping and haemodynamics

OBJECTIVE: To determine the effect of physical activity on diurnal blood pressure (BP) and haemodynamic variation. METHODS: Ambulatory measurements were performed during 24 h in 36 subjects (18 hypertensive, 13 male), aged 49.7 +/- 13.5 years. BP was recorded in the brachial artery. Physical activity and posture were measured with five acceleration sensors. RESULTS: Of the subjects 50% were dippers (nocturnal decrease in systolic or diastolic BP >/= 10%). Dippers and non-dippers had similar daytime BP, daytime, night-time, and day-night difference in physical activity, subjective sleep quality, and nocturnal cardiac output decrease (14.9 +/- 9.6 and 16.0 +/- 5.9%). In non-dippers vascular resistance increased from day to night by 9.7 +/- 8.3%, while it remained unchanged (-1.0 +/- 13.9%) in dippers. Day-night changes in heart rate and cardiac output were correlated with day-night changes in physical activity (r = 0.39 and 0.43), whereas day-night changes in systolic BP were correlated with night-time activity (r = -0.34). By selection of the active (i.e. walking) and inactive (i.e. not walking) periods during the day, we showed that physical activity has a large potential effect on dipping status and diurnal haemodynamic variation underlying BP variation. Depending on the BP taken (systolic or diastolic, respectively) the proportion of dippers increased to 81% or decreased to 25% if only the walking period was considered, whereas it decreased to 36% or increased to 53% if only the non-walking period was considered. CONCLUSIONS: Non-dippers differ from dippers by an increase of vascular resistance during the night. The degree of physical activity normally encountered during ambulatory monitoring has little influence on the diurnal BP profile or dipping status, but significantly influences underlying haemodynamics. Related to the different effects of posture and activity on systolic and diastolic BP, dipping classification may vary with the BP index taken.     

Circadian behavior of blood pressure and heart rate following orthotopic heart transplantation. Studies before and during antihypertensive therapy

The de novo hypertension, which develops in most cardiac transplant recipients within the first postoperative months, is multicausal, though toxic side-effects of cyclosporin A seem to play a key role. In order to analyze the circadian behavior of arterial blood pressure and heart rate after cardiac transplantation (HTX) and to evaluate the effect of an antihypertensive regimen on these parameters, 24-h noninvasive ambulatory blood pressure and heart rate monitoring was performed in 10 hypertensive cardiac transplant recipients on cyclosporin A (mean age 42.3 +/- 11.2 years, 14.3 +/- 8.3 months after HTX) before antihypertensive therapy and after introduction of an antihypertensive regimen with the ACE-inhibitor enalapril plus furosemide alone or combined with verapamil. The study demonstrated a complete loss of the usual nocturnal decline in blood pressure in cardiac transplant recipients (mean systolic and diastolic blood pressure 149 +/- 8 and 102 +/- 7 mm Hg during daytime and 152 +/- 8 and 104 +/- 9 mmHg at night). Antihypertensive therapy lowered the blood pressure level effectively, but did not influence the circadian pattern (mean systolic and diastolic blood pressure 121 +/- 8 and 81 +/- 4 mmHg during daytime and 121 +/- 9 and 83 +/- 3 mmHg at night, all p less than or equal to 0.001). Heart rate, in contrast, showed a significant, though in comparison to normal, a blunted decrease at night (mean heart rate 94 +/- 6 beats per min during daytime and 84 +/- 8 beats per min at night, p less than or equal to 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibition of awake sympathetic nerve activity of heart failure patients with obstructive sleep apnea by nocturnal continuous positive airway pressure

OBJECTIVES: This study was designed to determine whether reductions in morning systolic blood pressure (BP) elicited by treatment of moderate to severe obstructive sleep apnea (OSA) in heart failure (HF) patients are associated with a reduction in sympathetic vasoconstrictor tone. BACKGROUND: Daytime muscle sympathetic nerve activity (MSNA) is elevated in HF patients with coexisting OSA. In our recent randomized trial in HF, abolition of OSA by continuous positive airway pressure (CPAP) increased left ventricular ejection fraction (LVEF) and lowered morning systolic BP. METHODS: Muscle sympathetic nerve activity, BP, and heart rate (HR) of medically treated HF patients (EF <45%) and OSA (apnea-hypopnea index > or =20/h of sleep) were recorded on the morning after overnight polysomnography, and again one month after patients were randomly allocated nocturnal CPAP treatment or no CPAP (control). RESULTS: In nine control patients, there were no significant changes in the severity of OSA, MSNA, systolic BP, or HR. In contrast, in the 8 CPAP-treated patients, OSA was attenuated, and there were significant reductions in daytime MSNA (from 58 +/- 4 bursts/min to 48 +/- 5 bursts/min; 84 +/- 4 bursts/100 heart beats to 72 +/- 5 bursts/100 heart beats; p < 0.001 and p = 0.003, respectively), systolic BP (from 135 +/- 5 mm Hg to 120 +/- 6 mm Hg, p = 0.03), and HR (from 69 +/- 2 min(-1) to 66 +/- 2 min(-1); p = 0.013). CONCLUSIONS: Treatment of coexisting OSA by CPAP in HF patients lowers daytime MSNA, systolic BP, and HR. Inhibition of increased central sympathetic vasoconstrictor outflow is one mechanism by which nocturnal CPAP reduces awake BP in HF patients with moderate to severe OSA.     

Clinical trial of arotinolol in the treatment of hypertension: dippers vs. non-dippers.

To compare the effects of an alpha, beta blocker, arotinolol, in the treatment of essential hypertension between patients with a dipper and those with a non-dipper profile by means of 24-h ambulatory blood pressure monitoring (ABPM), a multicenter single blind parallel trial was carried out in five clinical centers. After a one-week single blind placebo run-in period, the patients underwent ABPM if their clinic diastolic blood pressure (DBP) ranged from 90-109 mmHg and their clinic systolic blood pressure (SBP) was <180 mmHg. They were divided into two groups according to the absence (non-dipper group, 24 cases) or presence (dipper group, 23 cases) of nocturnal BP reduction > or =10% of daytime BP. ABPM was measured again at the end of the active treatment phase. All patients were given Arotinolol 10-20 mg twice daily for 4 weeks. Twenty four-hour systolic and diastolic average BPs (MSBP, MDBP), 24-h systolic and diastolic blood pressure load (LS BP, LDBP), daytime systolic and diastolic average BPs (dMSBP, dMDBP), daytime systolic and diastolic blood pressure load (dLSBP, dLDBP), nighttime systolic and diastolic average BPs (nMSBP, nMDBP) and nighttime systolic and diastolic blood pressure load (nLSBP, nLDBP) were calculated. Arotinolol was effective in 78.2% of dippers and 54.2% of non-dippers, but the difference in effectiveness between these groups was not statistically significant. After treatment, SBP and DBP-including 24-h, daytime and nighttime systolic and diastolic BPs- were significantly reduced in both groups. During the daytime period, the systolic and diastolic blood pressures were significantly reduced in both dippers and non-dippers, while nighttime systolic and diastolic blood pressures were significantly reduced only in the non-dipper group. No significant changes were found in the dipper group over this period. In conclusion, Arotinolol, which can be dosed twice daily, is an effective antihypertensive agent which effectively lowers blood pressure during the day while reducing nighttime blood pressure more in non-dippers than in dippers, without excessive lowering blood pressure in the latter.     

Clinical utility and applicability of smoothness index, normalized smoothness index and individualized RDH index during treatment of essential hypertension

The purpose of this study was to assess the clinical utility of the smoothness index (SI) and normalized SI (SIn), measures of duration and homogeneity of blood pressure (BP) reduction, during an observation period without antihypertensive therapy followed by a treatment period using dihydropyridines (DHP) in 54 newly diagnosed and previously untreated subjects (age 46.9 +/- 9.1 years) with essential hypertension. In addition, we aimed to describe the reduction-duration-homogeneity (RDH) index for statistical assessment of the BP reduction in the individual patient. Twenty-four-hour BP was lowered during treatment (139.2 +/- 13.9/ 91.0 +/- 7.6 mmHg vs 130.9 +/- 11.3/85.2 +/- 5.2 mmHg, p < 0.001/p = 0.001). SI showed great interindividual variation, and increased from zero to 0.9 +/- 0.8 (systolic BP) and 0.8 +/- 0.7 (diastolic BP) after treatment (p < 0.001 for both), similar results were obtained for SI(n). The RDH index revealed BP reduction in agreement with the change in individual 24-h, daytime and night-time BP. Although SI and SI(n) may add important information regarding the homogeneity of the antihypertensive effect in a group of patients, and the RDH index for the individual patient, conclusions regarding antihypertensive efficacy can be obtained from assessment of the 24-h, daytime and night-time BP changes and ambulatory BP profiles. Based on our findings, we do not recommend the use of SI or RDH index in the clinical practice.     

Ambulatory blood pressure monitoring versus self-measurement of blood pressure at home: correlation with target organ damage

OBJECTIVE: Ambulatory blood pressure (BP) monitoring and home blood pressure measurements predicted the presence of target organ damage and the risk of cardiovascular events better than did office blood pressure. METHODS: To compare these two methods in their correlation with organ damage, we consecutively included 325 treated (70%) or untreated hypertensives (125 women, mean age = 64.5 +/- 11.3) with office (three measurements at two consultations), home (three measurements morning and evening over 3 days) and 24-h ambulatory monitoring. Target organs were evaluated by ECG, echocardiography, carotid echography and detection of microalbuminuria. Data from 302 patients were analyzed. RESULTS: Mean BP levels were 142/82 mmHg for office, 135.5/77 mmHg for home and 128/76 mmHg for 24-h monitoring (day = 130/78 mmHg; night = 118.5/67 mmHg). With a 135 mmHg cut-off, home and daytime blood pressure diverged in 20% of patients. Ambulatory and Home blood pressure were correlated with organ damage more closely than was office BP with a trend to better correlations with home BP. Using regression analysis, a 140 mmHg home systolic blood pressure corresponded to a 135 mmHg daytime systolic blood pressure; a 133 mmHg daytime ambulatory blood pressure and a 140 mmHg home blood pressure corresponded to the same organ damage cut-offs (Left ventricular mass index = 50 g/m, Cornell.QRS = 2440 mm/ms, carotid intima media thickness = 0.9 mm). Home-ambulatory differences were significantly associated with age and antihypertensive treatment. CONCLUSION: We showed that home blood pressure was at least as well correlated with target organ damage, as was the ambulatory blood pressure. Home-ambulatory correlation and their correlation with organ damage argue in favor of different cut-offs, that are approximately 5 mmHg higher for systolic home blood pressure.     

Beta-blockers do not impair the cardiovascular benefits of endurance training in hypertensives

Aerobic physical exercise is broadly recommended as a helpful adjunct to obtain blood pressure control in hypertension. Beta-blockade interacts with heart rate, sympathetic tone, maximal workload and local lactate production. In the present randomized-controlled study, we compared the cardiovascular effects of an endurance training programme in elderly hypertensives with or without beta-blockers and developed a first approach to determine a lactate-based training heart rate in presence of beta-blockade. Fifty-two patients (23 with beta-blocker, 29 without beta-blocker) > or =60 years with systolic 24-h ambulatory blood pressure (ABP) > or =140 mm Hg and/or antihypertensive treatment were randomly assigned to sedentary activity or a heart-rate controlled 12-week treadmill exercise programme (lactate 2.0 mmol/l). In the exercise group, the training significantly decreased systolic and diastolic 24-h ABP, blood pressure on exertion (100 W) and increased endothelium-dependent vasodilation (flow-mediated vasodilation, FMD) and physical performance both in the presence and absence of beta-blockade (P<0.05 each). The extent of ABP reduction did not significantly differ in the presence or absence of beta-blockade (Delta systolic ABP 10.6+/-10.5 vs 10.6+/-8.8 mm Hg, Delta diastolic ABP 5.7+/-8.6 vs 5.8+/-4.0 mm Hg). Mean training heart rate was significantly lower in the patients on beta-blockers (97.2+/-7.7 vs 118.3+/-7.5/min, P<0.001). Lactate-based aerobic endurance training evokes comparable cardiovascular benefits in the presence and absence of beta-blockade including a marked improvement of endothelial function. In the present study, target training heart rate with beta-blockers is about 18% lower than without.     

Office blood pressure underestimates ambulatory blood pressure in peripheral arterial disease in comparison to healthy controls

Patients with peripheral arterial disease (PAD) constitute a subgroup of high-risk hypertensives, but controlled studies on 24-h blood pressure (BP) and diurnal variation of BP are lacking. This study was performed in order to test the hypothesis that office BP (OBP) may underestimate 24-h BP in PAD patients in comparison to a matched control group. In all, 98 male patients (mean age 68 years) with a history of intermittent claudication and an ankle/brachial index less than 0.9, and 94 controls matched for age but without PAD or ischaemic heart disease performed 24-h recordings of ambulatory BP. A total of 59 patients had a history of hypertension and 69 were on treatment with BP-lowering drugs as compared to 17 and 23 of the control subjects, respectively. Office as well as 24-h systolic BP (SBP) were higher in patients as compared to controls (151 +/- 22 vs 140 +/- 20 mmHg, P < 0.001 and 142 +/- 14 vs 133 +/- 15 mmHg, P < 0.001, respectively), but did not differ with regard to diastolic BP. In an analysis of covariance with the continuous factors age, office SBP and the categorical factor antihypertensive treatment, 24-h SBP was higher in PAD patients compared to controls (P < 0.05). The difference between office and night SBP was lower in PAD patients with antihypertensive treatment compared to controls (P = 0.01). In conclusion, Male patients with PAD had higher systolic but not diastolic BP than age-matched control subjects. In PAD patients, 24-h SBP was higher than expected from OBP compared to controls. Night SBP was higher only in patients with antihypertensive treatment. In PAD patients, especially when on antihypertensive treatment, the severity of hypertension may be underestimated when based on OBP only.     

Ambulatory blood pressure monitoring in patients with hyperthyroidism before and after control of thyroid function

BACKGROUND AND OBJECTIVE: Thyroid hormones have pronounced effects on the cardiovascular system. Thyrotoxicosis affects blood pressure (BP), modifying both diastolic (DBP) and systolic (SBP) pressures. There are no studies examining BP with ambulatory blood pressure monitoring (ABPM) in hyperthyroidism before and after control of thyroid function. Our aims were (1) to analyse ABPM in a group of normotensive hyperthyroid patients before and after normalizing circulating thyroid hormones and (2) to compare these results with those obtained in a group of euthyroid subjects. PATIENTS AND MEASUREMENTS: We studied 20 normotensive hyperthyroid subjects [18 women; age (mean +/- SEM) 49.0 +/- 3.0 years] and 15 healthy subjects. Patients were evaluated by ABPM over 24 h, at diagnosis and after therapy (n = 18). RESULTS: The average 24-h, daytime and night-time SBP was significantly greater in hyperthyroid patients than in controls with no significant differences in DBP. Circadian BP rhythm, estimated by the difference between mean values of SBP, DBP and mean BP during daytime and night-time, was unchanged. The average 24-h and daytime SBP significantly decreased after normalizing thyroid function in the 18 hyperthyroid evaluated patients. Daytime SBP and DBP were higher than night-time values both before and after control of thyroid function. However, no differences in circadian BP rhythm were observed. CONCLUSIONS: Normotensive hyperthyroid patients exhibit higher ambulatory SBP throughout 24 h than normotensive euthyroid subjects. Control of hyperthyroidism decreases ambulatory SBP values. Mean nocturnal fall in BP is comparable in normotensive hyperthyroid patients and control subjects.     

Circadian rhythm of blood pressure in patients with obstructive sleep apnea.

AIMS: The aims of this study were to examine the circadian variation in blood pressure (BP) in obstructive sleep apnea (OSA) and to compare this between normotensive and hypertensive subjects. METHODS: We measured 24-hour ambulatory BP (ABP) in 72 men (mean age 51 +/- 8 years), with OSA diagnosed on overnight sleep study. Measurements of BP were made at 15 min intervals for 24 h using either an Oxford Medilog ABP or Spacelabs 90207 recorder. All recordings were performed after > or = 3 week washout of anti-hypertensive drugs. The day-time monitoring period was defined as 07:00 hrs to 22:00 and night-time 22:00 to 07:00. The ratio of night:day systolic and diastolic BP was calculated. RESULTS: The patients were obese (mean body mass index 33 +/- 5 kg/m2) with a central pattern of obesity (waist:hip ratio 0.99 +/- 0.14, normal < 0.94). The mean 24-h ABP (systolic/diastolic) was 138 +/- 18/88 +/- 12 mmHg. The mean daytime ABP was 143 +/- 18/93 +/- 12 and night-time ABP 128 +/- 20/80 +/- 12 Hg. The night:day BP ratio was 0.90 +/- 0.07 (systolic) and 0.87 +/- 0.09 (diastolic) indicating that average BP was lower during the night. This pattern was similar in normotensive and hypertensive subjects. In contrast there was a significant relationship between increasing BMI and night:day blood pressure ratio (r = 0.56, p < 0.001) independent of the effects of OSA. CONCLUSION: In contrast to previous studies, men with OSA have a normal diurnal pattern of blood pressure levels. These findings suggest that any influence of OSA on BP is manifested throughout the 24-h period.