Cuff and ambulatory blood pressure in subjects with essential hypertension

Evaluation of a new smartphone optical blood pressure application (OptiBP™) in the post-anesthesia care unit: a method comparison study against the non-invasive automatic oscillometric brachial cuff as the reference method

We compared blood pressure (BP) values obtained with a new optical smartphone application (OptiBP™) with BP values obtained using a non-invasive automatic oscillometric brachial cuff (reference method) during the first 2 h of surveillance in a post-anesthesia care unit in patients after non-cardiac surgery. Three simultaneous BP measurements of both methods were recorded every 30 min over a 2-h period. The agreement between measurements was investigated using Bland-Altman and error grid analyses. We also evaluated the performance of the OptiBP™ using ISO81060-2:2018 standards which requires the mean of the differences ± standard deviation (SD) between both methods to be less than 5 mmHg ± 8 mmHg. Of 120 patients enrolled, 101 patients were included in the statistical analysis. The Bland-Altman analysis demonstrated a mean of the differences ± SD between the test and reference methods of + 1 mmHg ± 7 mmHg for mean arterial pressure (MAP), + 2 mmHg ± 11 mmHg for systolic arterial pressure (SAP), and + 1 mmHg ± 8 mmHg for diastolic arterial pressure (DAP). Error grid analysis showed that the proportions of measurement pairs in risk zones A to E were 90.3% (no risk), 9.7% (low risk), 0% (moderate risk), 0% (significant risk), 0% (dangerous risk) for MAP and 89.9%, 9.1%, 1%, 0%, 0% for SAP. We observed a good agreement between BP values obtained by the OptiBP™ system and BP values obtained with the reference method. The OptiBP™ system fulfilled the AAMI validation requirements for MAP and DAP and error grid analysis indicated that the vast majority of measurement pairs (≥ 99%) were in risk zones A and B.Trial Registration ClinicalTrials.gov Identifier: NCT04262323.

From Brain to Blood Vessel: Insights From Muscle Sympathetic Nerve Recordings: Arthur C. Corcoran Memorial Lecture 2020

Multiunit recordings of postganglionic sympathetic outflow to muscle yield otherwise imperceptible insights into sympathetic neural modulation of human vascular resistance and blood pressure. This Corcoran Lecture will illustrate the utility of microneurography to investigate neurogenic cardiovascular regulation; review data concerning muscle sympathetic nerve activity of women and men with normal and high blood pressure; explore 2 concepts, central upregulation of muscle sympathetic outflow and cortical autonomic neuroplasticity; present sleep apnea as an imperfect model of neurogenic hypertension; and expose the paradox of sympathetic excitation without hypertension. In awake healthy normotensive individuals, resting muscle sympathetic nerve activity increases with age, sleep fragmentation, and obstructive apnea. Its magnitude is not signaled by heart rate. Age-related changes are nonlinear and differ by sex. In men, sympathetic nerve activity increases with age but without relation to their blood pressure, whereas in women, both rise concordantly after age 40. Mean values for muscle sympathetic nerve activity burst incidence are consistently higher in cohorts with hypertension than in matched normotensives, yet women's sympathetic nerve traffic can increase 3-fold between ages 30 and 70 without causing hypertension. Thus, increased sympathetic nerve activity may be necessary but is insufficient for primary hypertension. Moreover, its inhibition does not consistently decrease blood pressure. Despite a half-century of microneurographic research, large gaps remain in our understanding of the content of the sympathetic broadcast from brain to blood vessel and its specific individual consequences for circulatory regulation and cardiovascular, renal, and metabolic risk.

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

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

Comparison of daily anti-hypertensive effects of amlodipine and nifedipine coat-core using ambulatory blood pressure monitoring - utility of "hypobaric curve" and "hypobaric area"

When selecting anti-hypertensives, most physicians do not consider daily blood pressure (BP) variation. To evaluate the effectiveness of anti-hypertensives on the temporal profile of BP, we proposed three new parameters obtained by ambulatory BP monitoring and evaluated these parameters by comparing 5 mg of amlodipine and 40 mg of nifedipine coat-core. Hypobaric values were determined by subtracting BP data collected before administration of the drug from those collected after drug treatment at the corresponding time of day. The hypobaric curve was drawn by plotting the hypobaric values in chronological order, with the time at which the drug was taken set as the starting point. The hypobaric area was the area encircled between the 0 mmHg level line and the hypobaric curve. For amlodipine, the hypobaric areas of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were -19,110 mmHg/min and -10,695 mmHg/min, respectively. Systolic BP decreased -13.3 mmHg, and DBP BP -7.4 mmHg as daily averages. For nifedipine coat-core, the hypobaric areas of SBP and DBP were -32,235 mmHg/min and -18,150 mmHg/min, respectively. Systolic BP decreased -22.3 mmHg and DBP -12.6 mmHg as daily averages. From the hypobaric curves, the trough-to-peak ratios of amlodipine and nifedipine coat-core were measured as 0.67 and 0.60, respectively. The total anti-hypertensive power of nifedipine coat-core, measured by the hypobaric area, was 1.69 times more potent than that of amlodipine. These parameters seem to be useful for evaluating the daily temporal profile of the BP-lowering effects of anti-hypertensive drugs.

Orienting-Defense Responses and Psychophysiological Reactivity in Isolated Clinic versus Sustained Hypertension

This study sought to determine whether patients with white-coat or isolated clinic hypertension (ICH) show, in comparison to patients with sustained hypertension (SH), a defense response pattern to novel stimuli and an enhanced psychophysiological reactivity to stress. Forty-three patients with essential hypertension were divided into two groups after 16 days of self-monitoring blood pressure (BP): ICH (24 men; self-measured BP < 135/85 mmHg) and SH (19 men; self-measured BP >or= 135/85 mmHg). Defense responses were measured as the cardiac changes to phasic non-aversive auditory stimuli. Psychophysiological reactivity (heart and breath rate, blood volume pulse, electromyography, and skin conductance) was measured during mental arithmetic and video game tasks. The standard deviation of self-measured BPs and the difference between mean BPs at work and at home were used as indicators of cardiovascular reactivity to daily stress. No significant differences were seen in defense responses or psychophysiological reactivity to laboratory or naturally occurring stressors. These results do not support the hypothesis that ICH can be explained in terms of a generalized hyperreactivity to novel or stressful stimuli.

Home readings of blood pressure in assessment of hypertensive subjects

Out-patient clinic blood pressure (OPC-BP) was compared to home blood pressure (Home-BP) measured three times daily during a two week period in 122 consecutively referred hypertensive subjects. A semi-automatic device (TM-101) including a microphone for detection of Korotkoff-sounds, self-deflation of cuff pressure and digital display of blood pressure was used. Mean difference between OPC-BP and Home-BP was systolic +13 mm Hg (range -21 - +100 mg Hg) and diastolic +5 mm Hg (range -27 - +36 mm Hg). Although a significant correlation could be demonstrated between Home-BP and OPC-BP, the inter-individual scatter was pronounced and unpredictable from the hypertensive organ damages. It is argued, that home readings should be used to greater extent in the evaluation of patients with hypertension.

Estimation of base blood pressure by using a new device in the outpatient clinic

Direct measurement of intra-arterial blood pressure (BP) for 24-h provides approximately 100,000 values that vary enormously, but each (BPi) can be expressed by the equation BPi = BP0 + DeltaBPi (BP0, base BP; DeltaBPi, BP increment, i=1, 2, ..., 100 x 10(3)). About 20% of outpatients with hypertension exhibit white-coat hypertension (WCH). In such patients, DeltaBPc (i = c; c, time at the clinic) is surmised to be large. A method for explaining the physiological factors in DeltaBPc and the estimation of base BP in the outpatient clinic is important. This study addresses this issue. A total of 293 subjects were divided into four groups: 1) WCH group, 45 individuals (office BP > or = 140/90 mmHg and 24-h indirect BP < 125/80 mmHg); 2) normotensive (NT) group, 84 controls matched for age and sex; 3) WHO-I group, 95 hypertensive patients with WHO stage I (office BP > or = 140/90 mmHg and 24-h BP > or = 125/80 mmHg); and 4) WHO-II group, 69 hypertensive patients with WHO stage II. Their BPc and heart rate (HR; HRc, clinic HR) values were measured by a BP-ECG monitoring device in the outpatient clinic. Power-spectral analysis was used to obtain the ratio between the low-frequency component (LF) and high-frequency component (HF) of ECG-RR variability (LF/HF = LH). Twenty-four-hour indirect BP (and BP0) and base HR (HR0) were measured by a portable device (TM2425) at 30-min intervals. Then, DeltaBPc (= BPc - BP0) was estimated by performing linear multivariate analysis applying the model equation DeltaBPc = (BPc -alphaLH)(1-betaHR0/HRc) + epsilon to the above variables (alpha and beta, constant values; epsilon, error). This model equation made it possible to estimate BP0 (and DeltaBPc) with a high coefficient of correlation (r > or = 0.85, mean of error less than 0.82 +/- 5.9 mmHg). The predictive accuracy for discrimination between WCH and sustained hypertension (WHO-I and WHO-II groups) by this equation was 88%. The new DeltaBP-estimation device (BP-ECG monitor) enabled us to infer BP0 and is therefore useful in estimating WCH in the outpatient clinic.

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.

Cardiac damage in hypertensive patients with inverse white coat hypertension. Hospitalet study

BACKGROUND

Few studies have assessed the relationship between ambulatory blood pressure (BP) and cardiac damage in essential hypertensive patients with inverse white coat hypertension (IWCH).

OBJECTIVES

To determine the frequency of IWCH in untreated grade 1-2 hypertension and to assess possible differences in cardiac damage among patients with IWCH, white coat hypertension (WCH) and the rest of patients with grade 1-2 hypertension.

PATIENTS AND METHODS

Two hundred and eleven patients with grade 1-2 hypertension were sequentially included. A good quality 24-h ambulatory BP monitoring was obtained in 204 patients (age: 41 +/- 12 years, 56% males). IWCH was defined as a daytime systolic and/or diastolic BP higher than diagnostic office systolic and/or diastolic BP, respectively. WCH was defined as a daytime BP < 135/85 mmHg. A good quality echocardiogram was obtained in 174 patients. We considered left ventricular hypertrophy a left ventricular mass index (LVMI) > or = 125 g/m2.

RESULTS

We found IWCH in 29 subjects (14%), and WCH in 68 (33%). Office BP in patients with IWCH was in an intermediate position between WCH and the rest of grade 1-2 hypertension patients. The IWCH patients showed 24-h, daytime and night-time BP higher than the other groups. Left ventricular mass was significantly greater in patients with IWCH than in the other grade 1-2 hypertension patients after adjusting for age, gender, body mass index, smoking and office BP (regression coefficient 28.14, 95%CI: 7.36-48.91).

CONCLUSION

IWCH is independently associated with higher values of left ventricular mass in patients with grade 1-2 hypertension.

Findings of ambulatory blood pressure monitoring and heart rate variability in patients with Behcet's disease

Although we found lack of a decrease in nocturnal blood pressure, impaired heart rate variability, and diastolic dysfunction in patients with Behcet's disease, we could not demonstrate whether or not this finding has a prognostic value in patients with this disease.

What is the white-coat effect and how should it be measured?

The white coat effect is conceived as a measure of the blood pressure response to a clinic visit, but there is no agreement as to exactly how it should be defined. The most widely used definition is the difference between the average clinic and daytime ambulatory blood pressures, but other methods that have been used include the difference between clinic and home pressures, measurements using ambulatory blood pressures only, clinic measurements only, and laboratory (reactivity) testing. Few studies have compared the different methods, but the reactivity method has reported bigger changes of blood pressure and heart rate than the others. The effect tends to be greater in older than younger patients, in women than in men, but is present to a greater or lesser degree in almost all hypertensive patients. It is diminished but not obliterated by drug treatment. It is not closely related to overall blood pressure variability, and does not predict cardiovascular risk. The white coat effect appears to be idiosyncratic to the clinic setting.

Patient-specific differences between blood pressure estimated from 24 h ambulatory measurements and serial office self-recordings

The long-term true blood pressure, estimated in terms of the repeatable 24 h ambulatory mean (24 hAmb) pressure, is probably best related to progressive cardiovascular deterioration and is vital for clinical decision-making. Serial self-measurements (SELF) under quiet conditions may reflect this level, but with an annoying uncertainty in individual patients. This uncertainty is characterized by analyzing differences between the SELF readings of seated/supine patients on their own and the reference 24 hAmb values based on 72 recordings. From at-random replicated sessions of 59 subjects, the sources of uncertainty can be separated into three components: a systematic (non-random) variable difference in level from person to person, a mean systematic difference in level between methods, and random variability determining repeatability between sessions. An unstable alerting reaction distorts about six initial self-recordings and increases the random variability. The following 7-12 or 13-24 'steady-state' values show a comparable random variability but reflect the 24 hAmb level only when compared as the average of all patients. The standard deviation for repeatability is about 50-100% higher for SELF than for 24 hAmb. The patient-specific difference between methods contributes more than +/-10 mmHg to the uncertainty interval of the SELF results. These patient-specific differences recur at repeat sessions and thus cannot be reduced by averaging the results of sequential SELF sessions. In contrast, two 24 hAmb results provide a 95% uncertainty interval of +/-5 mm Hg. Thus, the averaged results of multiple SELF sessions can be used to detect major changes in blood pressure but are, as a result of patient-specific differences, too unreliable when the value to be estimated (the true value) is the expected long-term value of 24 hAmb results.

[Medical stress and blood pressure]

BP measurement by a physician may trigger a blood pressure and heart rate increase often referred to as the white coat effect. This pressure response may occur both in normotensive and hypertensive subjects. The identification of such individuals is usually not possible on a clinical basis. This identification is however important because white coat effect and permanent hypertension do not share the same prognosis, the white coat effect being associated with a low rate of cardiovascular complications. To avoid an important overestimation of the real blood pressure level due to this white coat effect, it is possible to increase the delay before blood pressure measurements (beyond 15 minutes) or to take into account measurements made by nurses. Reading may also have a favorable consequence. However, a blood pressure recording outside the office, that is an ambulatory or a home blood pressure measurement, is the only way to confirm the presence of a white coat effect. The decision to treat is based on this measurement.

Factors associated with the occurrence and magnitude of earthquake-induced increases in blood pressure

BACKGROUND

Blood pressure increases transiently after a major earthquake, but the characteristics and the mechanism of this increase are unknown.

METHODS

The study involved 124 elderly hypertensive outpatients from two clinics near the epicenter of the Hanshin-Awaji earthquake (7.2 on the Richter scale) for whom ambulatory blood pressure monitoring and assessment of end-organ damage had been performed before the earthquake.

RESULTS

During the 1 to 2 weeks after the earthquake, while major aftershocks persisted, mean (+/- SD) systolic blood pressure was 14 +/- 16 mm Hg greater and mean diastolic blood pressure was 6 +/- 10 mm Hg greater, but these values returned to baseline by 3 to 5 weeks after the earthquake. The earthquake-induced increase in blood pressure correlated significantly with the "white coat" effect ([clinic systolic blood pressure minus 24-hour systolic blood pressure] r = 0.34, P <0.001), body mass index (r = 0.28, P <0.001), and age (r = 0.24, P <0.01). The earthquake-induced blood pressure increase was prolonged in patients with microalbuminuria for at least 2 months after the earthquake, whereas it was less pronounced in patients who had been treated with an alpha-blocker and in patients with diabetes mellitus.

CONCLUSIONS

These elderly patients with hypertension had a substantial increase in blood pressure after a major earthquake; the increase was usually transient, except in patients who had microalbuminuria. The correlation with white-coat hypertension suggests that both phenomena are related to sympathetic activation.

Loss of nocturnal dipping of blood pressure and heart rate in obesity-induced hypertension in rabbits

We have investigated in rabbits whether overfeeding and weight gain, which lead to hypertension, are associated with changes in circadian rhythm of blood pressure (BP) and heart rate, and whether the sympathetic nervous system is involved in these changes. In adult male rabbits, mean arterial pressure (MAP) and heart rate (HR) were monitored by telemetry 22 h a day. Daily MAP and HR records were divided into four equal intervals and used to calculate day-night differences. After a 1-week control period, animals were switched to a high-fat (HFD) ad libitum diet for 8 weeks. HFD increased whole day MAP and HR, and rapidly abolished the normal diurnal rhythm of MAP and HR. Since HFD abolished the nocturnal dip in MAP, but had little effect on daytime values, the loss of dipping appears to account for most of the hypertension in this model of obesity. In a separate set of rabbits, alpha- and beta-adrenergic blockade (terazosin + propranolol) prevented HFD-induced hypertension and attenuated the increase in HR by more than half. Adrenergic blockade alone abolished the diurnal rhythm of MAP, chiefly by preventing daytime elevation of MAP. The addition of HFD ad libitum did not further modify daily MAP or its circadian pattern. The diurnal rhythm of HR was relatively unaffected by alpha + beta blockade alone, but was abolished after switching to HFD. In conclusion, rabbits fed an HFD ad libitum develop hypertension and tachycardia associated with a loss of the normal diurnal rhythm of MAP and HR. The hypertension appears to be sympathetically mediated.

Interchangeability of ambulatory and office blood pressure: limitations of reproducibility and agreement

A possible equivalence of office (Off) patient-recorded blood pressure (BP) and ambulatory (Amb) BP was evaluated. The criteria were the between-visits reproducibility (R) of oscillometrically measured supine office (Off), seated Off, and 24-h Amb BP and the agreement between Off and Amb data. Randomly ordered sessions were completed within 4 months in 59 untreated patients with Amb 24-h BP 136/87 (SD 14/10) mmHg and HR 72 (SD 9). R improves as SD of differences between sessions decreases with the number (n) of values included in the average so that SDD = a n(-b), where a and b are constants for each method, data sampling strategy, and group. R of a few steady Off data is better than R of a few Amb data. As n of the averaged values increases, R of Off and Amb methods converges and with n approximately 24 becomes identical. Only further increase in n of Amb data makes R of the Amb method superior than the Off method. The variably elevated initial Off BP distorts R and agreement. After approximately 6 readings, Off BP stabilizes at a lower "steady" level. "Steady" data averaged over visits are close to the Amb 24-h average from two sessions. Supine Off "steady" level is close to supine levels before sleep. The Off versus Amb method agreement improves by averaging "steady" BP from one up to four Off sessions, up to 7 "steady" Off readings over a session, and BP in both arms. At best the SBP agreement is within +/- 7.6 mmHg in 90% of cases with 24-h Amb S/D BP ranging 115-155/75-105 mmHg. The casually elevated BP can be evaluated only by the demonstrated between-visits reproducible 24-h Amb average or by the nearly equivalent average of multiple "steady" data from two to four Off visits.

Psychological variables in hypertension: relationship to casual or ambulatory blood pressure in men

OBJECTIVE

The evidence linking hypertension with personality or psychological characteristics, such as anger, anxiety, or depression, remains equivocal. This may be due in part to limitations of personality theory, confounding by awareness of hypertension, and/or inherent difficulties in measuring blood pressure. This study was designed to investigate the association between mild hypertension as defined by both ambulatory and casual (clinic) blood pressure measurements and various measures of personality and psychological characteristics.

METHODS

We examined this association in a population-based sample of 283 men between the ages of 30 and 60 years from eight work sites in New York City, using an ambulatory blood pressure monitor and controlling for age, race/ethnicity, and body mass index.

RESULTS

We found no consistent difference between participants with mild hypertension and those with normal blood pressure on any of the psychological variables assessed, including Type A behavior pattern, state and trait anger, anger expression, anxiety, symptoms of psychological distress, locus of control, or attributional style. Results were not due to the use of antihypertensive medication by some of the participants with hypertension nor to the dichotomization of blood pressure into those with and without mild hypertension. This contrasts with previous findings from this study showing a sizable association of ambulatory blood pressure and hypertension with job strain (a situational measure), age, and body mass index.

CONCLUSIONS

These null results suggest that situational, biological, and perhaps behavioral factors are the primary determinants of mild hypertension and that the predictive significance of psychological or dispositional factors is low or negligible in those without overt cardiovascular disease.

Attenuation of the "white-coat effect" by antihypertensive treatment and regression of target organ damage

This study assessed whether 2 common surrogate measures of the "white-coat effect," namely the clinic-daytime and the clinic-home differences in blood pressure (BP), were attenuated by long-term antihypertensive treatment and whether this attenuation is relevant to the treatment-induced regression of left ventricular hypertrophy, thus having clinical significance. We considered data from 206 patients with essential hypertension (aged 20 to 65 years) who had a diastolic BP between 95 and 115 mm Hg and echocardiographic evidence of left ventricular hypertrophy. In each patient, clinic BP, 24-hour ambulatory BP, and left ventricular mass index were assessed at baseline, after 3 and 12 months of treatment with an angiotensin-converting enzyme inhibitor, and after a final 4-week placebo run-off period. At baseline, the clinic-daytime differences in systolic and diastolic BP were 12.1+/-15.4 and 6.8+/-10.1 mm Hg, respectively; the corresponding values for the clinic-home differences were 5.7+/-10.6 and 2.9+/-6.1 mm Hg, respectively. These differences were reduced by 57.6% and 77.1% (P<0.01) and by 65.7% and 64.3% (P<0.01), respectively, after 12 months of treatment, with a partial return toward the pretreatment differences after the final placebo period. The observed treatment-induced reductions in left ventricular mass index and those in the clinic-daytime or clinic-home differences for systolic and diastolic BP showed no significant relationship when tested by multiple regression analysis. This provides the first longitudinal evidence that clinic-daytime and clinic-home differences in BP have no substantial value in predicting the regression of target organ damage, such as left ventricular hypertrophy, that has prognostic relevance.

Echocardiographic studies on elderly patients with white coat hypertension to evaluate cardiac organ damages

This case-control study was aimed at evaluating the distribution of some echocardiographic signs of cardiac organ damages in elderly patients with white coat hypertension (WCH), as compared with a normotensive group of elderly. Correlations between the signs of cardiac organ damages and the clinical and ambulatory blood pressure parameters (obtained by means of a 24-h monitoring) have also been evaluated. The first screening covered 258 elderly subjects of both sexes, aged from 65 to 82 years, with clinical diagnosis of hypertension (systolic and diastolic blood pressures being higher than 160 and 95 mmHg, respectively). Of this group, 116 subjects remained in the final pool, and their echocardiographic parameters were compared with 33 normotensive (N) subjects. Out of the 116 clinically hypertensive patients, 29 (25%) displayed WCH, according to the established criteria. Variance analyses on the ranks followed by Dunn's test revealed no statistically significant differences between the N and WCH groups, while the hypertensive group (H) proved to be significantly different from both the N and the WCH groups. In addition to the descriptive statistics, an analysis of correlations between the pressure variables and the echocardiographic parameters has also been performed by means of a forward-stepwise multiple linear regression method. The models generated by this regression analysis covered only the ambulatory diurnal systolic pressure, and the clinical diastolic pressure in most of the cases of the echocardiographic parameters, taken as independent variables. In all these cases, the standardizecl correlation coefficient of the diurnal systolic pressure was always higher than that of the clinical diastolic pressure, indicating that the echocardiographic parameters depend more strongly on the first than on the second pressure value.

Differences in behavior profile between normotensive subjects and patients with white-coat and sustained hypertension

It has been hypothesized that white-coat hypertensives (WCHs) have lower cardiovascular risk than sustained hypertensives (HTs), but higher emotional reactivity. We evaluated 92 HT patients (clinic and daytime BP>140/90 mmHg), 52 WCHs (clinic BP>140190 and ambulatory daytime BP<134/ 85 mmHg), and 74 normotensive subjects (NTs, clinic BP<140/90 and ambulatory daytime BP<134/85 mmHg), aged between 24 and 72 years, and matched for educational level, age, gender, and weight for depression, psychopathology, well-being, and quality of life. HTs showed worse scores than WCHs and NTs on most of the psychological variables; no differences were found between WCHs and NTs except on physical mobility. Daytime BP variability was HTs>WCHs>NTs, whereas nighttime BP variability was HTs>WCHs=NTs. We conclude that HTs have worse psychological profiles than the other two groups. WCHs and NTs have similar psychological profiles, although WCHs have a higher daytime BP variability, which is not associated with higher emotional reactivity.

Cardiovascular outcome in white-coat versus sustained mild hypertension: a 10-year follow-up study

BACKGROUND

The aim of this study was to compare the risk conferred by white-coat versus sustained mild hypertension for the development of cardiovascular disease.

METHODS AND RESULTS

Patients (n=479) who underwent 24-hour intra-arterial ambulatory blood pressure monitoring on the basis of a persistently elevated clinic systolic blood pressure of 140 to 180 mm Hg were followed up for the development of subsequent cardiovascular events during a 9.1+/-4. 2-year period. White-coat hypertension, defined as a clinic systolic blood pressure of 140 to 180 mm Hg associated with a 24-hour ambulatory systolic blood pressure <140 mm Hg and diastolic blood pressure <90 mm Hg, was present in 126 patients, and the remainder had sustained mild hypertension. A subgroup of patients without complications underwent follow-up echocardiography and carotid ultrasound. White-coat hypertensives were younger (44+/-12 versus 52+/-10 years, respectively; P<0.001) and had a significantly lower incidence of cardiovascular events (1.32 versus 2.56 events per 100 patient-years, respectively; P<0.001) than sustained hypertensives. Multivariate analysis revealed age (P=0.002), sex (P=0.007), race (P=0.001), smoking (P=0.005), and the presence of white-coat hypertension (hazard ratio, 0.29; 95% CI, 0.09 to 0.90; P=0.04) to be independent predictors of subsequent cardiovascular events. Subgroup analysis in patients without complications revealed a lower incidence of left ventricular hypertrophy and lesser degrees of carotid hypertrophy in the white-coat group.

CONCLUSIONS

These findings indicate a relatively benign outcome in white-coat hypertension compared with sustained mild hypertension.

Limitations of the difference between clinic and daytime blood pressure as a surrogate measure of the 'white-coat' effect. Syst-Eur investigators

BACKGROUND

The difference between clinic and ambulatory average daytime blood pressures is frequently taken as a surrogate measure of the 'white-coat effect' (i.e. the pressor reaction triggered in the patient by the physician's visit).

OBJECTIVE

To assess the reproducibility of this difference and its relationship with clinic and average ambulatory daytime blood pressure levels.

DESIGN AND METHODS

These issues were addressed with two large groups of subjects in whom both clinic and ambulatory blood pressures were measured, namely 783 outpatients with systolic and diastolic essential hypertension [Group 1, aged 50.8+/-9.4 years (mean +/- SD)], participating in standardized Italian trials of antihypertensive drugs, and 506 elderly patients (group 2, age 71+/-7 years) with isolated systolic hypertension, participating in the European Syst-Eur trial.

RESULTS

The clinic-daytime blood pressure difference for the essential systolic and diastolic hypertensive patients (group 1) was 13.6+/-14.3 mmHg for systolic and 9.1+/-8.6 mmHg for diastolic blood pressure (P always < 0.01). This difference for the elderly patients with isolated systolic hypertension (group 2) was 21.2+/-16.0 mmHg for systolic and only 1.3+/-10.2 mmHg for diastolic blood pressure (P < 0.01 and P < 0.05, respectively). In both studies little or no systematic clinic-daytime difference could be observed for heart rate. The reproducibility of the clinic-daytime blood pressure difference, tested for 108 essential systolic and diastolic hypertensive patients from group 1 and 128 isolated systolic hypertensives from group 2, was invariably lower than that both of daytime and of clinic blood pressure values. Finally, the clinic-daytime blood pressure difference was progressively higher for increasing levels of clinic blood pressure and progressively lower for higher levels of ambulatory daytime blood pressure.

CONCLUSIONS

Thus, the clinic-daytime blood pressure difference has a limited reproducibility; depends not only on clinic but also on daytime average blood pressure, which means that its size is a function of the blood pressure criteria employed for selection of the patients in a trial; and is never associated with a systematic clinic-daytime difference in heart rate, which further questions its use as a reliable surrogate measure of the true pressor response induced in the patient by the doctor's visit.

Nocturnal blood pressure and relation to vasoactive hormones and renal function in hypertension and chronic renal failure

The purpose of this study was to assess the blood pressure profile and to measure vasoactive hormones in patients with essential hypertension (n=61), secondary hypertension (n=32) and chronic renal failure (n=32) matched with healthy control subjects (n=35), and to study the relationship between circadian changes in blood pressure and baseline levels of vasoactive hormones and renal function. Non-invasive, automatic blood pressure measurement was performed for 24 or 48 h. Venous plasma concentrations of renin, angiotensin II, aldosterone, arginine vasopressin, atrial natriuretic peptide and endothelin were measured. The mean 24-h blood pressure was higher in all groups of hypertensive patients than in control subjects. The nocturnal blood pressure fall was preserved in essential hypertension, in contrast to secondary hypertension in which it was attenuated. In the patients with chronic renal failure the 24-h mean blood pressure was the same as in the controls. Night-time blood pressure was higher among the chronic renal failure patients than in the control group, and the nightly blood pressure fall in both diastolic and systolic blood pressure was reduced. Plasma concentrations of renin activity, arginine vasopressin, atrial natriuretic peptide, aldosterone and endothelin were significantly increased in secondary hypertension and chronic renal failure, compared to essential hypertension and control subjects. Plasma angiotensin II was increased in chronic renal failure compared to essential hypertension and controls. Estimated creatinine clearance and nightly blood pressure dips were inversely correlated in essential and secondary hypertension, i.e. with a decreasing renal function both systolic and diastolic nightly blood pressure dips were gradually attenuated. In the whole group of patients the nightly systolic and diastolic blood pressure dips were negatively correlated to basal plasma renin activity, plasma aldosterone and atrial natriuretic peptide levels, i.e. the higher the basal plasma hormone level the lower the blood pressure dip. In conclusion, patients with essential hypertension have elevated but normally configured 24-h blood pressure profiles, and patients with different kinds of secondary hypertension have elevated 24-h blood pressure profiles and attenuated nightly systolic and diastolic blood pressure falls. The more the renal function is reduced and the more the plasma levels of renin and aldosterone are increased, the more the nocturnal fall in blood pressure is reduced. It is suggested that the attenuated or absent decrease in nocturnal blood pressure in secondary renal hypertension is caused by an abnormally increased secretion of vasoactive hormones and/or by so far unknown factors released from the diseased kidney.

Prediction of mortality by ambulatory blood pressure monitoring versus screening blood pressure measurements: a pilot study in Ohasama

OBJECTIVE

To compare the prediction of mortality by ambulatory blood pressure monitoring and screening blood pressure measurements in a general population.

DESIGN

A prospective cohort study.

PATIENTS AND METHODS

We obtained blood pressure data for 1542 subjects (565 men and 977 women) aged > or = 40 years who were followed up for up to 8.1 years (mean 5.1 years). Subjects were subdivided into five groups according to their ambulatory and screening blood pressure levels. The prognostic significance of blood pressure for mortality was examined by the Cox proportional hazards regression model.

RESULTS

The association between blood pressure level and mortality was more distinctive for the ambulatory blood pressure than it was for the screening blood pressure. The risk of cardiovascular mortality increased significantly for the highest quintiles of 24 h ambulatory blood pressure, whereas there was no significant association between the screening blood pressure and the cardiovascular mortality. When both 24 h and screening blood pressure values were included in the Cox model, only the systolic ambulatory blood pressure was related significantly to the increased risk of cardiovascular mortality.

CONCLUSIONS

The ambulatory blood pressure had a stronger predictive power for mortality than did the screening blood pressure. This appears to have been the first study of the prognostic significance of ambulatory blood pressure monitoring versus screening blood pressure measurements in a general population.

Twenty-four-hour ambulatory blood pressure and vasoactive hormones in valvular aortic disease

The aim of this study was to assess the blood pressure profile and vasoactive hormones in valvular aortic disease. Thirteen aortic stenosis and/or aortic regurgitation patients were matched with 13 control subjects. Ambulatory blood pressure monitoring was performed for 24 h. Arterial and venous plasma concentrations of renin, angiotensin II, aldosterone, arginine vasopressin, atrial natriuretic peptide, immunoreactive endothelin and cyclic-GMP were measured. The mean 24-h blood pressure was higher in the patient group (94.9 mmHg) compared with control subjects (88.2 mmHg) (p < 0.0001), despite no differences in daytime blood pressures. The nocturnal blood pressure fall was attenuated in the patients (systolic/diastolic blood pressure -8.5/-3.5; -20.3/-14.3 mmHg (p < 0.001/p < 0.01)); in heart rate too the nightly fall was blunted in the patients (-4.8/ -13.4/min (p < 0.0013)). PRA, Ang II, AVP, ANP, ir-ET and cGMP were significantly increased in the patients compared to the controls. Nightly systolic blood pressure fall was inversely related to arterial (r = -0.75, p < 0.003) and venous (r = -0.65, p < 0.04) plasma renin activity and arterial aldosterone (r = -0.64, p < 0.05) in valvular aortic disease patients. In conclusion, valvular aortic disease patients have attenuated falls in blood pressure and heart rate during the night. Increased activity in the renin aldosterone system may be involved in this abnormal blood pressure regulation.

Clinical implications of white coat hypertension

OBJECTIVE

To determine the clinical implications of mild white coat hypertension (WCH).

SUBJECTS AND METHODS

We studied 102 subjects (54 men, 48 women), 51 of whom were normotensive and 51 slightly hypertensive. None had ever received antihypertensive therapy. An ambulatory blood pressure (ABP) record (Accutracker II), a 24-h electrocardiogram and an echocardiogram were obtained from each, and each was examined by funduscopy. WCH subjects were compared with sustained hypertension (SH) subjects and with normotensives.

RESULTS

Fifty-three percent of the hypertensives qualified as WCH. The ultrasonographic characteristics and the ABP variables of the WCH group differed significantly from those of normotensives, but not from those of the SH group. The prevalence of left ventricilar hypertrophy (LVH) in the SH group (62.5%) did not differ significantly from its prevalence in the WCH group (40.7%), but the prevalence among normotensives (17.6%) was significantly lower than in either of the other two groups. The WCH and SH groups did not differ significantly as regards the prevalence of hypertensive retinopathy (33.3% in the former, 58.3% in the latter). For no non-LVH, non-retinopathic subject, whether normotensive or hypertensive, were more than 18% of daytime diastolic ABP measurements > or = 90 mmHg. Ultrasonographic findings were no better correlated with ABP than with in-clinic BP measurements. Fundus findings correlated well with in-clinic BP and with numerous ABP parameters. Retinopathy, with or without LVH, was efficiently predictable among hypertensives on the basis of body mass index and the 24-h maximum of systolic BP.

CONCLUSIONS

Myocardiac remodelling and vascular retinopathy develop early and in parallel in hypertensives, and both developments appear to involve determinants including body mass index and 24-h maximum systolic BP. WCH subjects, as defined by current ABP-based criteria, have cardiac and retinovascular characteristics different to normotensive subjects. Stricter criteria are needed to discriminate between hypertensives with and without the systemic developments that constitute the immediate source of risk to the hypertensives individual.

Exercise blood pressure predicts mortality from myocardial infarction

Apparently healthy men (n=1999, 40 to 59 years old) were investigated from 1972 through 1975 to determine whether systolic blood pressure during bicycle ergometer exercise predicts morbidity and mortality from myocardial infarction beyond that of casual blood pressure taken after 5 minutes of supine rest. During a follow-up of 31 984 patient-years (average, 16 years), 235 subjects had myocardial infarctions, of which 143 were nonfatal and 92 were fatal. Exercise blood pressure was more strongly related than casual blood pressure to both morbidity and mortality from myocardial infarction. Among 520 men with casual systolic blood pressure = 140 mm Hg, 304 increased their systolic blood pressure to > or = 200 mm Hg during 6 minutes of exercise at an initial workload of 600 kpm/min. These 304 men had an excessive risk of myocardial infarction (18.8% versus 9.5% among the 1294 men with casual blood pressure < 140 mm Hg and exercise blood pressure < 200 mm Hg; P < .001). As many as 58% of those with myocardial infarction in this group died, compared with 33% (range, 26% to 35%) for all other groups (P=.0011), including those with casual blood pressure > or = 140 mm Hg and exercise blood pressure < 200 mm Hg. Thus, exercise blood pressure is a stronger predictor than casual blood pressure of morbidity and mortality from myocardial infarction, and an early rise in systolic blood pressure during exercise adds prognostic information about mortality from myocardial infarction among otherwise healthy middle-aged men with mildly elevated casual blood pressure. We suggest that blood pressure taken during standardized exercise testing may distinguish between severe and less severe hypertension.

Is white coat hypertension associated with arterial disease or left ventricular hypertrophy?

Although white coat hypertension may be present in 20% or more of hypertensive individuals, its prognostic significance is unknown. We compared prognostically relevant measures of target-organ damage among 24 individuals with white coat hypertension and age- and sex-matched groups of sustained hypertensive and normotensive subjects classified by clinical and 24-hour ambulatory blood pressures. Left ventricular and carotid artery structure and function were evaluated by ultrasonography. Left ventricular mass index was similar in white coat hypertensive (82 +/- 17 g/m2) and normotensive (78 +/- 15 g/m2) subjects but was higher in sustained hypertensive subjects (97 +/- 19 g/m2, P < .02 and P < .002, respectively). Similarly, carotid artery intimal-medial thickness was greater in the sustained hypertensive group (0.98 +/- 0.21 mm) than in the white coat hypertensive (0.84 +/- 0.16 mm, P < .05) and normotensive (0.76 +/- 0.18 mm, P < .001) groups. The prevalence of discrete atherosclerotic plaques was higher in the sustained hypertensive group (58%) than in the white coat hypertensive (25%, P < .05) and normotensive (21%, P < .02) groups. Cardiac and carotid structure in individuals with white coat hypertension resemble findings in normotensive subjects and differ significantly from those in age- and sex-matched sustained hypertensive subjects. These findings suggest that white coat hypertension may be a benign condition for which pharmacological intervention may not be necessary, a hypothesis that needs to be tested in longitudinal studies with clinical end points.

Influence of isolated diastolic hypertension identified by ambulatory blood pressure on target organ damage

Clinical decisions and controlled studies in regard to hypertension have long emphasized the casual diastolic blood pressure (DBP). The influence of superimposition of high systolic blood pressure (SBP) on the target organ damage has been less studied. To assess the role of isolated diastolic hypertension without interference of superimposition of systolic hypertension, 171 subjects with normal blood pressure, isolated diastolic hypertension (SBP < 140 and DBP > or = 90 mmHg) isolated systolic hypertension (SBP > or = 140 and DBP < 90 mmHg) or combined hypertension (SBP > or = 140 and DBP > or = 90 mmHg) determined by mean 24-h ambulatory blood pressure were compared in relation to target organ damage including ECG abnormality related to hypertension, cardiac enlargement by chest X-ray, proteinuria and retinopathy. The incidence of target organ damage was lower in subjects with normal BP than in the other three groups. The incidence of target organ damage was almost significantly higher in patients with isolated systolic hypertension than in those with isolated diastolic hypertension. No significant difference in the incidence of complications existed between patients with isolated systolic and combined hypertension. These findings demonstrate that the severity of hypertensive complications is more closely related to mean ambulatory SBP than mean ambulatory DBP. The level of systolic BP is important for predicting the severity of target organ damage in patients with high diastolic BP, because there is a significant difference in the incidence of target organ damage between isolated diastolic hypertension and combined hypertension.

Predictors of the pressor response to the clinic visit in essential hypertensives with and without diabetes mellitus

Predictive models for the pressor response to the outpatient clinic visit (PRC) in essential hypertensives with and without diabetes are proposed. The hypotheses are derived from previous studies about the univariate correlates of this response. PRC was measured with ambulatory monitors. Twenty-four hour blood pressures and average PRCs were similar in the two groups. Diabetics had faster 24-h heart rates, decreased heart rate variability, a broader range of PRCs and more depressor responders. PRC of nondiabetics correlated with duration of hypertension and was dependent on race; the predictive model had R2 of 0.19. In contrast, PRC of diabetics exhibited correlations with age, weight, BP and blood glucose and the model had R2 of 0.71. The data suggest that: diabetics had autonomic dysfunction, that their PRC can be modelled with predictors that are accepted correlates of autonomic neuropathy, and that these predictors attenuated PRC or its buffering. If these results were confirmed by prospective application of the model to a larger group of patients, 'true' blood pressures could be estimated by subtraction of predicted PRC from office blood pressures in diabetic, but not in nondiabetic, hypertensive patients.

Exercise blood pressure predicts cardiovascular mortality in middle-aged men

The outcome of 1999 apparently healthy men aged 40 to 59 years investigated from 1972 through 1975 was ascertained after 16 years to determine whether systolic blood pressure measured with subjects in the sitting position during a bicycle ergometer exercise test adds prognostic information on cardiovascular mortality beyond that of casual blood pressure measured after 5 minutes of supine rest. During a total follow-up of 31,984 patient years, 278 patients died, 150 from cardiovascular causes. Casual blood pressure and pulse pressure as well as peak exercise systolic blood pressure during 6 minutes on the starting workload of 600 kpm/min (approximately 100 W, 5880 J/min) were all related to cardiovascular mortality. The relative risk (RR) of dying from cardiovascular causes associated with an increment of 48.5 mmHg (= 2 SD) in systolic blood pressure at 600 kilopondmeter (kpm)/min was significant (RR = 1.5, 95% confidence interval [CI] = 1.1-2.3, P = .040) even when adjusting for a large number of variables measured in the present study, including age, exercise capacity, smoking habits, and casual blood pressures. The influence of blood pressure at 600 kpm/min was so strong that the predictive value of resting casual blood pressures became nonsignificant when these were analyzed as continuous variables also including exercise blood pressure as a covariate. However, the maximal systolic blood pressure during the exercise test was unrelated to cardiovascular mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Nocturnal arterial hypotension and its role in optic nerve head and ocular ischemic disorders

We measured 24-hour ambulatory blood pressure monitoring and diurnal curve of the intraocular pressure in 166 white patients with anterior ischemic optic neuropathy, normal-tension glaucoma, primary open-angle glaucoma, and other optic nerve head disorders. Hourly average blood pressure data analyses showed a significant (P < .0001) decrease in mean systolic (26%) and diastolic (33%) blood pressure measurements at night. A significantly (P = .0028) lower nighttime mean diastolic blood pressure and a significantly (P = .0044) greater mean percentage decrease in diastolic blood pressure were noted in normal-tension glaucoma than in anterior ischemic optic neuropathy. Patients with arterial hypertension taking oral hypotensive therapy showed a significant association between progressive visual field deterioration and nocturnal hypotension, particularly in anterior ischemic optic neuropathy. Intraocular pressure showed no significant correlation with visual field deterioration in any of these conditions. Our findings suggest that nocturnal hypotension, in the presence of other vascular risk factors, may reduce the optic nerve head blood flow below a critical level, and thereby may play a role in the pathogenesis of anterior ischemic optic neuropathy and glaucomatous optic neuropathy; that is, nocturnal hypotension may be the final insult in a multifactorial situation. The same mechanisms may be true of a number of other ocular ischemic disorders. This finding opens a new dimension in the understanding and management of these visually disabling diseases.

Is white coat hypertension innocent? Structure and function of the heart in the elderly

To evaluate the morphological and functional characteristics of the heart in elderly patients with white coat hypertension, we performed an echocardiographic study in 67 elderly individuals older than 60 years: 17 patients with white coat hypertension, 34 patients with true hypertension, and 16 normotensive control subjects. White coat hypertension was defined as a mean 24-hour ambulatory systolic blood pressure of less than 140 mm Hg associated with office hypertension. Cardiac responses to an isometric handgrip exercise test were used to evaluate left ventricular functional reserve. Left atrial dimension and left ventricular mass index were significantly greater in the white coat hypertension group than in the normotension group (P < .05) but were similar to values in the true hypertension group. Left ventricular diastolic function, expressed by peak late-early filling ratio of diastolic mitral flow, showed increasing impairment in the order of the normotension, white coat hypertension, and true hypertension groups (analysis of variance, P < .05); the ratio in the white coat hypertension group tended to be higher than that in the normotension group (unpaired t test, P = .054). The relation between fractional shortening and end-systolic stress did not shift downward after handgrip exercise in the white coat hypertension group, indicating that functional reserve in the left ventricle was maintained. Thus, patients with white coat hypertension had a moderately increased left atrial dimension and left ventricular mass in association with a tendency for disturbed diastolic function, although systolic functional reserve remained the same. These findings suggest that white coat hypertension in the elderly may not be innocent.

Ambulatory blood pressure of adults in Ohasama, Japan

We performed a cross-sectional study in a small town in northern Japan to evaluate the distribution, reference values, and daily variation in ambulatory blood pressure. A total of 705 subjects (229 men aged 61.3 +/- 13.4 years [mean +/- SD] and 476 women aged 57.5 +/- 13.3 years; 41.1% of the regional adult population, n = 1716), including those treated with antihypertensive drugs (n = 231, 66.5 +/- 9.5 years) as well as untreated subjects (n = 474, 55.0 +/- 13.5 years), participated in the study. Both ambulatory and screening blood pressures were measured in 659 subjects. Ambulatory blood pressure was measured with an automatic device (Colin ABPM-630). The 24-hour ambulatory blood pressure in the total population was 121.7 +/- 13.0/71.1 +/- 7.6 mm Hg (95th percentile value [95%] = 146/85 mm Hg). The corresponding value in the untreated subjects was 119.4 +/- 12.5/70.1 +/- 7.4 mm Hg (95% = 144/83 mm Hg). The 24-hour average ambulatory blood pressure was 118.0 +/- 11.1/69.4 +/- 6.8 mm Hg (95% = 139/81 mm Hg) in subjects identified as normotensive by their screening blood pressure (n = 448, 57.2 +/- 13.1 years) and 133.6 +/- 14.2/78.9 +/- 8.8 mm Hg in those identified as hypertensive by their screening blood pressure (n = 73, 63.1 +/- 10.6 years). Based on the mean+SD of the 24-hour ambulatory blood pressure in the normotensive subjects by their screening blood pressure (129/76 mm Hg), the 24-hour ambulatory blood pressures in 25 (34.2%) of these 73 hypertensive subjects by screening blood pressure were below this level. Nine (2%) of 448 normotensive subjects by screening blood pressure were above the mean+2 SDs (140/83 mm Hg) of the 24-hour ambulatory blood pressure in the normotensive group by screening blood pressure. Ambulatory and screening blood pressures increased with age. The age-dependent increase in ambulatory blood pressure was less apparent in men. The 24-hour average pulse rate decreased with age. The daily variation in ambulatory blood pressure (standard deviation) increased with age, whereas that of pulse rate decreased with age. Increases in blood pressure variation were observed in nighttime and daytime blood pressure values. The differences between day versus night ambulatory blood pressures decreased with age in men but not in women.(ABSTRACT TRUNCATED AT 400 WORDS)

Postexercise hypotension. Key features, mechanisms, and clinical significance

Recent investigations have demonstrated that there is a sustained reduction in arterial blood pressure after a single bout of exercise, ie, postexercise hypotension (PEH). The purpose of this discussion is to integrate the available information on this topic and to review studies using sustained stimulation of somatic afferents in experimental rats as a model to study the role of somatic afferents in PEH. PEH occurs in response to several types of large-muscle dynamic exercise (ie, walking, running, leg cycling, and swimming) at submaximal intensities greater than 40% of peak aerobic capacity and exercise durations generally between 20 and 60 minutes. PEH is observed in both normotensive and hypertensive humans and in spontaneously hypertensive rats but is generally greater in magnitude in hypertensive subjects. The maximal exercise-induced reductions in systolic and diastolic arterial blood pressures have been on average 18 to 20 and 7 to 9 mm Hg, respectively, in hypertensive humans and 8 to 10 and 3 to 5 mm Hg, respectively, in normotensive humans. PEH has been reported to persist for 2 to 4 hours under laboratory conditions. Whether PEH is sustained for a prolonged period of time under free-living conditions remains controversial, although the results of one study indicate that PEH can persist for up to 13 hours. Possible mechanisms involved in mediating postexercise and poststimulation reductions in arterial blood pressure include decreased stroke volume and cardiac output; reductions in limb vascular resistance, total peripheral resistance, and muscle sympathetic nerve discharge; group III somatic afferent activation; altered baroreceptor reflex circulatory control; reduced vascular responsiveness to alpha-adrenergic receptor-mediated stimulation; and activation of endogenous opioid and serotonergic systems. It appears that the magnitude of PEH in hypertensive subjects is clinically significant; however, more investigation is required to determine if the duration is sufficient under real-life conditions to contribute to the reduction in blood pressure observed with chronic exercise conditioning.

Abnormal renal function in isolated systolic hypertension correlation with ambulatory blood pressure

Does ambulatory blood pressure correlate with the renal function damage better than clinic blood pressure in isolated systolic hypertension, as has been reported in other target organ involvement in combined systolic/diastolic hypertension? We investigated the correlation of serum beta-2 microglobulin concentration and both 24-h urine beta-2 microglobulin concentration and excretion as measures (suggestive) of glomerular filtration rate and tubular reabsorption, respectively with both ambulatory and clinic blood pressure in 19 health normotensive (68 +/- 4.9 years) and 50 isolated systolic hypertensive elderly individuals (69 +/- 5.4 years). Serum beta-2 microglobulin concentration and 24-h urine beta-2 microglobulin concentration and excretion were higher in the isolated systolic hypertension than in the normotensive group (P < 0.05). In isolated systolic hypertensive patients, 24-h urine beta-2 microglobulin concentration and excretion were related to ambulatory blood pressure (r = 0.32-0.40, P < 0.05), but not to clinic blood pressure; waking systolic blood pressure had the strongest correlation with both 24-h urine beta-2 microglobulin concentration and excretion among derivatives of ambulatory blood pressure (r = 0.35 and 0.40, P < 0.05). We conclude that ambulatory blood pressure, especially waking systolic blood pressure, is superior to clinical blood pressure in predicting renal function impairment, in isolated systolic hypertensive patients.

Psychophysiological reactivity and cardiac end-organ changes in white coat hypertension

This study aimed 1) to assess whether patients with an exaggerated blood pressure response to the doctor's presence ("white coat" effect) also display a pattern of enhanced blood pressure reactivity to mental stress and physical exercise and 2) to determine the presence of left ventricular structural and filling abnormalities in patients with white coat hypertension. We studied 56 (40 men) consecutive patients (mean [SD] age, 46.4 [9.1] years) whose clinic blood pressure was repeatedly high. Patients were classified as having white coat hypertension (n = 20) if both their mean daytime (from 7 AM to 11 PM) ambulatory systolic and diastolic blood pressures were less than 134 and 90 mm Hg, respectively. Patients were considered to have persistent hypertension (n = 36) if daytime systolic blood pressure was 134 mm Hg or more or diastolic blood pressure was 90 mm Hg or more. Eighteen subjects with clinic blood pressure lower than 140/90 mm Hg served as a normotensive control group. Blood pressure reactivity from baseline to mental arithmetic, isometric handgrip, and cycle ergometry did not display any difference among the three groups. The white coat hypertensive group had left ventricular mass index lower than the persistent hypertensive group but higher than the normotensive group. Doppler indexes of left ventricular diastolic filling displayed similar abnormalities in the white coat and persistent hypertensive groups compared with the normotensive group.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical value of blood pressure measurements: focus on ambulatory blood pressures

Because clinic blood pressure values are compromised by 2 major limitations--the alerting reaction to clinic measurements and the spontaneous blood pressure variability--they have only a limited correlation with average 24-hour blood pressure values. Whether the latter should be employed routinely in substitution for, or in addition to, traditional blood pressure measurements has not yet been determined, however. To date, average 24-hour blood pressure values have been shown to correlate more closely than clinic blood pressure values with the organ damage of hypertension. A correlation with organ damage has been shown also for a number of blood pressure values within the 24 hours. Nevertheless, the clinical importance of 24-hour blood pressure and blood pressure variability has never been confirmed by prospective controlled studies. This information needs to be obtained before this approach is routinely employed in the clinical practice.