Clinical value of ambulatory blood pressure monitoring

Publication guidelines for human heart rate and heart rate variability studies in psychophysiology-Part 1: Physiological underpinnings and foundations of measurement

This Committee Report provides methodological, interpretive, and reporting guidance for researchers who use measures of heart rate (HR) and heart rate variability (HRV) in psychophysiological research. We provide brief summaries of best practices in measuring HR and HRV via electrocardiographic and photoplethysmographic signals in laboratory, field (ambulatory), and brain-imaging contexts to address research questions incorporating measures of HR and HRV. The Report emphasizes evidence for the strengths and weaknesses of different recording and derivation methods for measures of HR and HRV. Along with this guidance, the Report reviews what is known about the origin of the heartbeat and its neural control, including factors that produce and influence HRV metrics. The Report concludes with checklists to guide authors in study design and analysis considerations, as well as guidance on the reporting of key methodological details and characteristics of the samples under study. It is expected that rigorous and transparent recording and reporting of HR and HRV measures will strengthen inferences across the many applications of these metrics in psychophysiology. The prior Committee Reports on HR and HRV are several decades old. Since their appearance, technologies for human cardiac and vascular monitoring in laboratory and daily life (i.e., ambulatory) contexts have greatly expanded. This Committee Report was prepared for the Society for Psychophysiological Research to provide updated methodological and interpretive guidance, as well as to summarize best practices for reporting HR and HRV studies in humans.

Assessment of salusin alpha and salusin beta levels in patients with newly diagnosed dipper and non-dipper hypertension

OBJECTIVE

The pathophysiology of non-dipper hypertension has not been clarified. The relationship between salusins with atherosclerosis and hypertension has gained attention in recent years. The aim of this paper is to investigate whether salusins are associated with circadian blood pressure, left ventricular mass index, and diastolic functions in newly diagnosed hypertensives.

METHODS

The study included 88 newly diagnosed hypertensive individuals. Twenty-four-hour ambulatory blood pressure monitoring and echocardiographic examinations were performed. The patients were assigned to dipper hypertension (n = 41) and non-dipper hypertension (n = 47) groups based on the ambulatory blood pressure monitoring results according to the presence of ≥ a 10% decrease in nighttime blood pressure values or not. Serum salusin α and β levels were determined by electrochemiluminescence immunological test method.

RESULTS

Compared to dipper hypertension, non-dipper hypertension group demonstrated lower salusin α levels (1818.71 ± 221.67 vs 1963 ± 200.75 pg/mL, p = .002), mitral E/A, septal E'/A' and higher salusin β levels (576.24 ± 68.15 vs 516.13 ± 90.7 pg/ml, p = .001) and left ventricular mass index. Multivariate logistic regression analysis revealed salusin-α (OR 0.474, 95% CI 0.262 to 0.986, p = .001), salusin-β (OR 2.550, 95% CI 2.123 to 2.991, p = .018), and left ventricular mass index (OR 2.620, 95% CI 2.124 to 2.860, p = .011) as independent predictors of non-dipper hypertension. As candidate markers to predict non-dipper hypertension, decreased salusin α, and increased salusin β levels may mediate crosstalk between sympathetic and parasympathetic systems and indicate poor cardiovascular prognosis in hypertension.

Associations of awake and asleep blood pressure and blood pressure dipping with abnormalities of cardiac structure: the Coronary Artery Risk Development in Young Adults study

OBJECTIVES

To evaluate the associations of high awake blood pressure (BP), high asleep BP, and nondipping BP, determined by ambulatory BP monitoring (ABPM), with left ventricular hypertrophy (LVH) and geometry.

METHODS

Black and white participants (n = 687) in the Coronary Artery Risk Development in Young Adults study underwent 24-h ABPM and echocardiography at the Year 30 Exam in 2015-2016. The prevalence and prevalence ratios of LVH were calculated for high awake SBP (≥130 mmHg), high asleep SBP (≥110 mmHg), the cross-classification of high awake and asleep SBP, and nondipping SBP (percentage decline in awake-to-asleep SBP < 10%). Odds ratios for abnormal left ventricular geometry associated with these phenotypes were calculated.

RESULTS

Overall, 46.0 and 49.1% of study participants had high awake and asleep SBP, respectively, and 31.1% had nondipping SBP. After adjustment for demographics and clinical characteristics, high awake SBP was associated with a prevalence ratio for LVH of 2.79 [95% confidence interval (95% CI) 1.63-4.79]. High asleep SBP was also associated with a prevalence ratio for LVH of 2.19 (95% CI 1.25-3.83). There was no evidence of an association between nondipping SBP and LVH (prevalence ratio 0.70, 95% CI 0.44-1.12). High awake SBP with or without high asleep SBP was associated with a higher odds ratio of concentric remodeling and hypertrophy.

CONCLUSION

Awake and asleep SBP, but not the decline in awake-to-asleep SBP, were associated with increased prevalence of cardiac end-organ damage.

The impact of blood pressure variability on coronary plaque vulnerability in stable angina: an analysis using optical coherence tomography

BACKGROUND

Blood pressure variability (BPV), especially visit-to-visit BPV, has been reported to be a risk factor for cardiovascular disease. The impact of BPV on coronary plaque vulnerability remains uncertain. The aim of this study was to investigate the relationship between BPV and coronary plaque vulnerability.

PATIENTS AND METHODS

From August 2013 to May 2014, 36 patients with both hypertension and stable angina pectoris who underwent a percutaneous coronary intervention guided by frequency-domain optical coherence tomography were investigated retrospectively. The size of the lipid cores and the thickness of the fibrous cap covering the lipid core were measured by frequency-domain optical coherence tomography, and we calculated the blood pressure coefficient of variation (CV) and SD as intraindividual visit-to-visit BPV.

RESULTS

Both SD and CV of systolic blood pressure (SBP) correlated positively with lipid arc (SBP-SD: r=0.68, P<0.01; SBP-CV: r=0.64, P<0.01) as well as average SBP (r=0.48, P<0.01). Fibrous cap thickness did not correlate with blood pressure variables or BPV.

CONCLUSION

BPV is related to coronary plaque volume, but not to coronary plaque vulnerability. In addition to conventional coronary risk factors, BPV may be a therapeutic target for coronary atherosclerosis.

Decoding white coat hypertension

There is arguably no less understood or more intriguing problem in hypertension that the "white coat" condition, the standard concept of which is significantly blood pressure reading obtained by medical personnel of authoritative standing than that obtained by more junior and less authoritative personnel and by the patients themselves. Using hospital-initiated ambulatory blood pressure monitoring, the while effect manifests as initial and ending pressure elevations, and, in treated patients, a low daytime profile. The effect is essentially systolic. Pure diastolic white coat hypertension appears to be exceedingly rare. On the basis of the studies, we believe that the white coat phenomenon is a common, periodic, neuro-endocrine reflex conditioned by anticipation of having the blood pressure taken and the fear of what this measurement may indicate concerning future illness. It does not change with time, or with prolonged association with the physician, particularly with advancing years, it may be superimposed upon essential hypertension, and in patients receiving hypertensive medication, blunting of the nighttime dip, which occurs in about half the patients, may be a compensatory mechanisms, rather than an indication of cardiovascular risk. Rather than the blunted dip, the morning surge or the widened pulse pressure, cardiovascular risk appears to be related to elevation of the average night time pressure.

Central pressures and central hemodynamic values in white coat hypertensives are closer to those of normotensives than to those of controlled hypertensives for similar age, gender, and 24-h and nocturnal blood pressures

INTRODUCTION

There is disagreement whether white coat hypertensives (WCH) have different hemodynamic and structural characteristics compared to normotensives (NT) and hypertensives (HT).

METHODS

We compared cardiovascular prognostic markers (pulse wave velocity [PWV] and aortic stiffness index [ASI]) and data on central hemodynamics and central pressures (augmentation index [AIx], augmentation pressure [AugP] and pulse pressure amplification [PPA]) from aortic pulse wave analysis between NT (n=175), WCH (n=315) and treated HT (n=691), all with 24-h blood pressure (BP) <130/80 and nocturnal BP <120/70 mmHg after matching for age, gender, body mass index (BMI) and and nocturnal BP. The groups were also compared separately in terms of 24-h systolic BP <120 mmHg and 120-129 mmHg.

RESULTS

The percentage of non-dippers was 40.1% in NT, 34.5% in WCH and 38.3 in HT. For similar 24-h and nocturnal systolic BP (NT 109/64±7/5, WCH 110/66±7/6, HT 109/64±7/5 mmHg), aortic stiffness was greater in HT (n=691, PWV 10.8±2.6 m/s and ASI 0.33±0.16, p<0.01) than in WCH (n=316, PWV 9.7±2.4 m/s and ASI 0.28±0.17) and NT (n=175, PWV 9.5±2.0 m/s and ASI 0.29±0.15); AugP and AIx were higher (p<0.01) in HT (13.9±8.2 and 29.6±12.6 mmHg) than in WCH (11.5±8.5 mmHg and 24.9±15.2) and NT (11.0±6.4 mmHg and 26.6±11.5). PPA was lower (p<0.01) in HT (11.3±5.5 mmHg) than in WCH (13.2±7.1 mmHg) and in NT (12.4±4.9 mmHg). The findings were similar when the 24-h systolic BP <120 mmHg and 120-129 mmHg subgroups were analyzed separately.

CONCLUSION

Our data suggest that for similar age, gender distribution, BMI, and 24-h and nocturnal BP, aortic stiffness, central aortic pressures and wave reflection in WCH are closer to those of NT than to those with treated HT. This supports the idea that white coat hypertension may be a more benign condition than treated hypertension for similar 24-h and particularly nocturnal BP levels.

Low-dose hydrocortisone replacement is associated with improved arterial stiffness index and blood pressure dynamics in severely adrenocorticotrophin-deficient hypopituitary male patients

OBJECTIVE

Increased cardiovascular and cerebrovascular morbidity and mortality in hypopituitary subjects may be linked to inappropriate glucocorticoid exposure; however, the pathophysiology remains unclear. We aimed to examine the effect of three commonly prescribed hydrocortisone (HC) regimens on vascular risk factors.

DESIGN

An open crossover study randomising ten hypopituitary men with severe adrenocorticotrophic hormone deficiency to three HC dose regimens: dose A (20mg mane and 10mg tarde), dose B (10mg mane and 10mg tarde) and dose C (10mg mane and 5mg tarde).

METHODS

Following 6 weeks on each regimen, participants underwent 24-h serum cortisol sampling, 24-h ambulatory blood pressure (BP) measurements, calculation of the Ambulatory Arterial Stiffness Index (AASI), oral glucose tolerance testing and fasting serum osteoprotegerin (OPG) sampling.

RESULTS

There were no differences in 24-h BP between dose regimens and controls; however, low-dose HC replacement (dose C) was associated with the lowest AASI, indicating a less stiff arterial tree (P<0.05) compared with the other dose regimens. Loss of the physiologic nocturnal BP dip was more common in higher HC replacement regimens, although only significant for dose B compared with dose C (P=0.03). Twenty per cent of patients had abnormal glucose tolerance, but this was unrelated to dose regimen. OPG correlated strongly with 24-h BP in those on dose A only (r=0.65, P=0.04).

CONCLUSION

Currently prescribed HC replacement doses do not result in significant differences in absolute BP levels or improvements in insulin sensitivity. However, lower HC doses may result in lower arterial stiffness and a more physiological nocturnal BP dip. Long-term studies are required to confirm these findings and evaluate their impact on vascular morbidity in this patient group.

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

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

Blood pressure fluctuation and hypertension in patients with Parkinson's disease

OBJECTIVES

Blood pressure (BP) abnormalities have been known in Parkinson's disease (PD) patients. The present study aimed at determining how the BPs of PD patients fluctuate in a day.

METHODS

A total of 37 PD patients and 44 OD (other disease) patients, all of who were inpatients, were monitored every 30 min by 24-h ambulatory blood pressure monitoring (ABPM).

RESULTS

The average systolic BP and the number of patients who showed postprandial hypotension were not different between the two groups. However, occurrence of nocturnal hypertension, BP fluctuation of over 100 mmHg in a day and BP of over 200 mmHg were significantly more frequently observed in the PD patients than in the OD patients. In the PD patients, these parameters were not different between those who were suffering from the disease for less than 10 years and those with the disease for 10 years or longer, as well as between those who had a Hoehn-Yahr staging scale of 2-3 and those with a scale of 4-5.

CONCLUSION

Twenty-four-hour ABPM, not BP measurement once a day, enables us to determine the actual BP in PD patients. Although hypotension is a severe risk factor for falling and syncope, we emphasize the importance of monitoring rather hypertension and fluctuating BP in PD patients that may lead to a variety of other undesirable conditions. Management of hypotension, hypertension, and BP fluctuation is an important issue in the future.

Effect on blood pressure of a continued nursing intervention using chronotherapeutics for adult Chinese hypertensive patients

AIMS AND OBJECTIVES

(1) To explore the effect of continued nursing intervention on hypertensive patients based on chronotherapeutics. (2) To identify the factors affecting hypertensive patients' compliance to the chronotherapeutics-oriented nursing interventions.

BACKGROUND

Chronotherapy provides a means of individual treatment for hypertension according to the circadian blood-pressure profile of each patient and constitutes a new option in optimising blood-pressure control and reducing risk from hypertension.

DESIGN

Experimental study.

METHODS

All participants enrolled were randomly divided into the intervention group and the control group and they all took antihypertensive medicine prescribed by their doctors under ambulatory blood pressure monitoring. According to individual ambulatory blood pressure monitoring measures, interventions were implemented.

RESULTS

(1) There were significant differences in blood pressure and compliance to chronotherapeutics between the two groups before and after the intervention. (2) Single variant and multiple factors analysis revealed different characteristics influencing chronotherapeutic compliance of hypertensive patients.

CONCLUSIONS

Under ambulatory blood pressure monitoring, continued nursing intervention for hypertensive patients guided by chronotherapeutics could effectively improve blood-pressure control and chronotherapeutic compliance.

RELEVANCE TO CLINICAL PRACTICE

Health care providers who deal with Chinese hypertensive patients can improve patients' therapeutic compliance and blood pressure control guided by chronotherapeutics. According to different influencing factors on patients' chronotherapeutic compliance nurses should pay more attention to those whose compliance might be worse.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Choroidal blood-flow responses to hyperoxia and hypercapnia in men with obstructive sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) impacts on macrovasculature and autonomic function and may therefore interfere with ocular microvascular regulation. We hypothesized that choroidal vascular reactivity to hyperoxia and hypercapnia was altered in patients with OSA compared with matched control subjects and would improve after treatment with continuous positive airway pressure (CPAP).

METHODS

Sixteen healthy men were matched 1:1 for body mass index, sex, and age with 16 men with newly diagnosed OSA without comorbidities. Subjects underwent sleep studies, 24-hour blood pressure monitoring, arterial stiffness measurements, and cardiac and carotid echography. Overall, patients were middle-aged, lean, and otherwise healthy except for having OSA with a limited amount of desaturation, with, at most, subclinical lesions of the cardiovascular system, stage 1 hypertension, or both. Choroidal laser Doppler flowmetry provides a unique opportunity to assess microvascular function by measuring velocity, (ChBVel), volume (ChBVol), and relative subfoveal choroidal blood flow (ChBF). Vascular choroidal reactivity was studied during hyperoxia and hypercapnia (8% CO2) challenges before and after treatment with nasal CPAP.

RESULTS

Patients with OSA and control subjects exhibited similar choroidal reactivity during hyperoxia (stability of choroidal blood flow) and hypercapnia (significant increases in ChBVel of 13.5% and in ChBF of 16%). Choroidal vasoreactivity to CO2 was positively associated with arterial stiffness in patients with OSA. Gas choroidal vasoreactivity was unchanged after 6 to 9 months of CPAP treatment.

CONCLUSION

This study showed unimpaired choroidal vascular reactivity in otherwise healthy men with OSA. This suggests that patients with OSA, without comorbidities, have long-term adaptive mechanisms active in ocular microcirculation.

Impact of a Pharmaceutical Care Intervention on Blood Pressure Control in a Chain Pharmacy Practice

BACKGROUND

Hypertension affects over 50 million Americans, with only 50% of patients being adequately controlled. Several pharmacist counseling and pharmacist-physician comanagement studies have documented that community pharmacist interventions improve blood pressure (BP) management.

OBJECTIVE

To determine whether community pharmacists can improve clinical endpoints including hypertension control, drug therapy dosing, adherence to prescribed regimens, adverse drug reaction incidence, patient understanding, response to therapy, and quality-of-life.

METHODS

The program included the education and training of a group of 18 chain community pharmacists in hypertension therapies, monitoring, and management. Protocols and documentation tools were based on nationally accepted clinical practice guidelines for hypertension in place at the time of the study. Pharmaceutical care (PC) was then compared with usual care (UC) over a 12-month period.

RESULTS

The study initially enrolled 180 PC and 196 UC patients, with 44% (PC) and 32% (UC) of the patients reporting a final BP measurement. A larger proportion (50%) of PC patients who had poorly controlled hypertension at baseline (>140/90 mm Hg) were controlled compared with UC patients (22%). The average reduction in systolic BP was 9.9 mm Hg in PC patients compared with 2.8 mm Hg in UC patients (p < 0.05). Changes in diastolic BP were similar in the PC and UC groups. Based on patient self-report, PC patients were more likely to say that they take their medicines as prescribed compared with UC patients (p < 0.05). The 1- to 6-month antihypertensive adherence rate was higher in PC patients (0.91 ± 0.15) compared to UC patients (0.78 ± 0.30) (p = 0.02); there was no significant difference in adherence rate during the 7- to 12-month period.

CONCLUSIONS

Community pharmacists can positively affect patient medication adherence during the 6-month period following counseling by a pharmacist along with an improvement in patient BP. However, there is much room for improvement in PC programs and in the number of patients who properly adhere to their medications.

Hypertension and TIA

Transient ischemic attack is a medical emergency because early stroke risk after transient ischemic attack is high. Hypertension is the most important modifiable risk factor for stroke and transient ischemic attack. The aims of this review are to provide a summary of the current knowledge concerning the relationship between blood pressure and transient ischemic attack, as well as outline issues regarding diurnal variation and the potential of chronotherapy (timing medications to accord with diurnal patterns of blood pressure). There is a strong relationship between hypertension and the incidence of transient ischemic attack and the subsequent short-term risk for stroke. Ambulatory blood pressure monitoring is a reliable diagnostic and monitoring tool for hypertension and provides additional information about diurnal variation in blood pressure. Different diurnal blood pressure patterns may confer variable stroke risk. Patients with stroke commonly have abnormal diurnal blood pressure patterns and this may relate, in part, to autonomic nervous system dysfunction. However, blood pressure patterns have not been systematically studied in patients with transient ischemic attack. Blood pressure remains poorly controlled in a large proportion of patients after transient ischemic attack and under-treatment and poor adherence are important factors. Chronotherapy for blood pressure may result in more effective blood pressure control. More research is needed in this area. Hypertension is strongly associated with transient ischemic attack. Diurnal blood pressure patterns may influence subsequent stroke risk after transient ischemic attack and more evidence is needed to inform clinical practice to improve blood pressure management for transient ischemic attack patients.

Continuous monitoring of intraocular pressure: rationale and progress toward a clinical device

Intraocular pressure (IOP) is a dynamic physiologic parameter with regular circadian variations and unpredictable short-term and long-term fluctuations. Current methods of measuring IOP are suboptimal with a typical clinical practice only performing periodic IOP measurements during regular office hours. Diurnal and 24-hour IOP measurements obtained on an in-patient basis can increase measurements but are inconvenient and expensive, and do not allow ambulatory monitoring of IOP. The goal of continuous IOP monitoring is to provide automated 24-hour recording of ambulatory IOP. Continuous IOP monitoring involves 2 complementary paradigms. Temporary noninvasive monitoring, possibly involving a contact lens-based pressure sensor, would be used to measure 24-hour IOP on a periodic basis. Permanent monitoring would be more invasive, using an implantable pressure sensor. Despite numerous previous attempts at continuous IOP monitoring, a device suitable for clinical use is not yet available. However, devices currently in development for permanent IOP monitoring seem to be nearly ready for human testing. The technologic issues for temporary monitoring may be greater than for permanent monitoring.

Noninvasive Psychophysiological Ambulatory Recordings

Rapid technical developments have greatly facilitated noninvasive 24-hour recording of physiological signals at relatively low costs, including blood pressure, activity of the autonomic nervous system, respiratory behavior, and activity of the hypothalamic-pituitary-adrenocortical axis. Ambulatory noninvasive recordings can be used to study the baseline levels of these physiological variables as well as their reactivity to naturalistic stressors. Levels and reactivity can be compared across groups differing in exposure to risk factors (e.g., stress, genotypes) or used to sharpen the clinical profile of individual subjects (e.g., in panic or somatoform disorders). The focus of the current paper is on the importance of a priori choices in study design and data analysis strategies when ambulatory recording specifically targets the reciprocal relationship between physiological and psychological events. These choices are illustrated with ambulatory-assessed indices of the cardiac autonomic nervous system, blood pressure, respiration, and cortisol secretion.

Lower cognitive performance in 81-year-old men with greater nocturnal blood pressure dipping

Abnormal day-to-night blood pressure (BP) pattern have been found to be associated with cerebrovascular damage, yet studies of the elderly 80 years of age and above, for whom the risk pattern may be different due to ageing and age-associated diseases, are lacking. Ninety-seven 81-year-old men underwent ambulatory BP monitoring and were given six cognitive tests, 79 of the men completing the cognitive test battery. The odds ratio (OR) for performing one standard deviation below the mean on any cognitive test was calculated using a forward stepwise logistic regression model, confounding factors being controlled for. Groups defined in terms of day-to-night changes in BP were compared in this respect. Cognitive performance was lower (OR 3.6; P = 0.017) in the group usually described as dippers (10%–20% nocturnal drop in systolic BP [SBP]) as compared with nondippers (<10% drop). The tertile with the greatest SBP fall (10.6%–19.8%, a range considered as normal among middle aged) showed lowest cognitive performance (OR 4.7; P = 0.008) as compared with the middle tertile (5.1%–10.5% drop). The mean nocturnal fall in SBP was 7.4%, significantly greater in those with lower rather than higher cognitive performance. A nocturnal drop in SBP of ≥10% was associated with lower cognitive performance in these elderly men. The limits to normal dipping appear to be shifted in the direction of a lesser drop in the very elderly.

Target organ status in white-coat hypertensives: usefulness of serum procollagen type I propeptide in the respect of left ventricular diastolic dysfunction

BACKGROUND

Myocardial fibrosis is a feature of diastolic dysfunction and target organ damage, which was compared among subjects with normotension (NT), white-coat hypertension (WCH) and essential hypertension (EH). Serum procollagen type I propeptide (PIP) level was assessed as a marker of diastolic dysfunction in WCH.

METHODS AND RESULTS

Of 90 subjects, 30 had NT and 30 had WCH (ambulatory daytime blood pressure <135/85 mmHg) and 30 had EH (untreated mild to moderate hypertension); all underwent biochemical and echocardiographic examinations. Those with WCH had a lower left ventricular (LV) mass index than those with EH, but it was higher than in the NT group. WCH patients had a lower mitral valve E/A ratio and a higher LV E/E' (E': septal mitral annular peak velocity) ratio than NT patients, whereas these values were higher and lower respectively than in the EH group. The LV E/E' ratio, an estimate of LV diastolic function, correlated with the serum PIP concentration in WCH patients (r=0.39, P=0.03).

CONCLUSION

WCH is an intermediate group between NT and EH in respect of target organ damage. These results show a relationship between LV diastolic function and serum PIP in WCH, so the serum PIP level may be a useful marker of diastolic dysfunction and target organ damage in such patients.

Diurnal blood pressure variation in the evaluation of early onset severe pre-eclampsia

OBJECTIVE

To study the association between diurnal variation in blood pressure, the mean daily blood pressure and various complications of pregnancy in patients presenting with severe pre-eclampsia before 34 weeks' gestation.

STUDY DESIGN

Forty-four women presenting to a tertiary hospital in South Africa with severe pre-eclampsia between 28 and 34 weeks' gestation were managed expectantly for at least 8 days. We measured maternal blood pressure every 30 min with the pregnancy validated Spacelabs 90209 automated blood pressure monitor for 24h periods on alternative days. The mean 24-h diastolic blood pressure measurement, the mean diastolic blood pressure for daytime and nighttime, the day-night blood pressure difference and the night-day ratio were compared with the occurrence of abruptio placentae, gestational age at delivery, neonatal intensive care unit admission, birth weight, abnormal umbilical artery Doppler FVW and reason for delivery.

RESULTS

One hundred and seventy-six 24-h studies were analyzed. The day-night blood pressure difference decreased with increasing mean diastolic blood pressure (r=-0.323, p<0.0001). A combination of normal mean diastolic blood pressure and normal day-night blood pressure difference was associated with increased gestational age and lower caesarean section rates.

CONCLUSION

The combination of mean diastolic blood pressure and day-night blood pressure difference may be a supplementary measurement of disease severity in early onset severe pre-eclampsia and seems to be of prognostic value.

The relationship between nighttime dipping in blood pressure and cerebral hemodynamics in nonstroke patients

Inadequate dipping in nighttime blood pressure (BP) is associated with cerebrovascular disease. The authors aimed to determine whether inadequate nocturnal dipping was associated with abnormalities in cerebrovascular hemodynamics in individuals without stroke. Participants in this study underwent 24-hour ambulatory BP monitoring followed by morning transcranial Doppler measurements of blood flow velocities (BFVs) in the middle cerebral artery during supine rest, head-up tilt, hypocapnia, and hypercapnia. Nighttime BP decline by <10% was considered nondipping. Of the 102 nonstroke participants (mean age, 53.6 years), 35 (34%) were dippers. Although nondippers had similar BFV and cerebrovascular resistance (CVR) while supine, they had a lower BFV (P=.04) and greater CVR (P=.02) during head-up tilt compared with dippers. Moreover, greater nighttime dipping in both systolic BP (P=.006) and diastolic BP (P=.03) were associated with higher daytime BFV and lower CVR (P=.01 for systolic BP; P=.02 for diastolic BP). Inadequate nocturnal BP dipping is associated with lower daytime cerebral blood flow, especially during head-up tilt.

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

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

Use of Plasma B-Type Natriuretic Peptide Level to Identify Asymptomatic Hypertensive Patients with Abnormal Diurnal Blood Pressure Variation Profiles: Nondippers, Extreme Dippers, and Risers

We examined the relationship between plasma B-type natriuretic peptide (BNP) level and diurnal variability pattern of blood pressure (BP). Twenty-four-hour ambulatory BP monitoring was performed in 98 patients with asymptomatic essential hypertension, and the patients were classified into four groups according to their circadian BP variation profiles: dippers (n=29), nondippers (n=36), extreme dippers (n=19), and risers (n=14). Plasma BNP was measured by enzyme immunoassay. Based on the distribution pattern of BNP values, the values were analyzed after logarithmic transformation. Significant differences in plasma BNP levels among the types of circadian BP variations were demonstrated by analysis of variance (p<0.0005). Nondippers and risers showed significantly higher plasma BNP levels (mean [range: -1 SD and +1 SD]: 16.1 [6.3, 41.6] pg/mL and 29.2 [15.9, 53.4] pg/mL, respectively) than dippers (8.4 [3.7, 19.1] pg/mL). The area under the receiver operating characteristics curve for distinguishing patients with abnormal circadian BP variation from those with normal variation was 0.72, indicating that plasma BNP levels were useful for distinguishing between these patients. Specificity of 69% and sensitivity of 72% were obtained with a cut-off value of 10.5 pg/mL (log plasma BNP, 1.02) for distinguishing the abnormal diurnal BP profile group from the normal group. In conclusion, hypertensive patients with abnormal diurnal BP variation patterns (nondippers, extreme dippers, and risers) showed higher plasma BNP levels than those with normal circadian BP variation (dippers). Plasma BNP level is clinically useful for the identification of hypertensive patients who have abnormal circadian BP variability, which increases the risk of cardiovascular events.

Utility of ambulatory blood pressure monitoring in children and adolescents

Diagnosis of hypertension is critically dependent on accurate blood pressure measurement. "Accurate" refers to carefully following the guidelines for blood pressure measurement laid out for children and adults to minimize observer and subject errors that commonly occur in clinical blood pressure measurement. Accurate blood pressure measurement is more important in children and adolescents as the misdiagnosis of hypertension may have a life-long adverse impact on insurability and employment. Automated blood pressure measurement offers multiple advantages in achieving high-quality blood pressure determinations by reducing observer errors. The most commonly used form of automated blood pressure measurement is 24-h ambulatory blood pressure measurement (ABPM). Information on ABPM in children has grown exponentially over the last decade. Normative data exists for diagnosis of hypertension in children using ABPM including a novel method for determining normal values with the LMS method. There is further information about the utility of different determinants of 24-h blood pressure such as dipping status, morning surge and blood pressure load. ABPM has been able to detect significant differences in blood pressure in many disease states in children including chronic renal failure, polycystic kidney disease, solitary functioning kidney, and after renal transplantation. Increasingly nonambulatory automated blood pressure determinations have been used in management of hypertension in children. Although nonambulatory automated readings lack information about nocturnal blood pressure or blood pressure during daily activity, studies have suggested that home automated blood pressure measurements are a helpful adjunct to the usual office blood pressure reading.

Ambulatory blood pressure monitoring and endothelium-dependent vasodilation in the elderly athletes

AIM

Regular exercise is a key component of cardiovascular risk prevention strategies, because it is associated with a variety of beneficial metabolic and vascular effects that reduce mortality and the incidence of cardiovascular adverse events. Endothelium plays an important role in the local regulation of vascular tone and structure, mainly by nitric oxide (NO) synthesis and action. Aim of the present study was to evaluate in elderly athletes the effect of regular aerobic exercise on arterial blood pressure (BP) and on endothelium-dependent flow-mediated dilation (FMD) of the brachial artery.

METHODS

The study population included 30 male subjects (mean age 65.6+/-5.6 years), who had practiced endurance running at a competitive level for at least 40 years, and 28 age- and sex-matched subjects (mean age 64.5+/-4.5 years) with sedentary lifestyle and free of cardiovascular disease. Athletes and control subjects underwent standard 12-lead ECG, clinic BP, 24-h ambulatory BP monitoring and endothelium-dependent FMD and endothelium-independent response to glyceryl trinitrate (GTN), 400 microg, in the brachial artery by high-resolution ultrasonography.

RESULTS

Systolic clinic and ambulatory 24-h BP were significantly lower in the athletes, than in the controls (P<0.001, respectively). Systolic and diastolic 24-h BP variability, when assessed either by the standard deviation (S.D.), or by the coefficient of variation (CV), were also significantly lower in the athletes (P<0.01). The athletes also had a lower 24-h, day-time and night-time heart rate (HR) (P<0.01), as well as a lower HR variability (P<0.01). As regards circadian BP change, the %Delta was statistically significant greater in athletes (P<0.05). Elderly athletes showed higher FMD than elderly sedentary subjects (P<0.001), whereas no differences were shown in the response to GTN.

CONCLUSIONS

Our results, suggest that long-term physical activity can counteract the age-related endothelial dysfunction that characterizes sedentary aging, preserving the capacity of the endothelium-dependent vasodilation and reduces BP values improving arterial pressure control.

Diabetes mellitus and stroke

The aim of this article was to describe (i) the epidemiology and outcomes of stroke relating to diabetes; (ii) the pathophysiology of diabetes as a risk factor for stroke; (iii) the management of acute stroke in patients with diabetes; (iv) the evidence of primary and secondary prevention of stroke in patients with diabetes; and (v) the risk of new-onset diabetes using older antihypertensive agents. The combination of diabetes and stroke disease is a major cause of morbidity and mortality worldwide. Evidence from large clinical trials performed in patients with diabetes supports the need for aggressive and early intervention to target patients' cardiovascular (CV) risks in order to prevent the onset, recurrence and progression of acute stroke. Identification of at-risk patients with diabetes and metabolic syndrome has also allowed the delivery of early and effective intervention to reduce stroke risks, while active treatment during the acute phase of stroke will reduce long-term neurological and functional deficits. While the ongoing debate on the risk benefits of different antihypertensive, lipid-lowering and antiplatelet agents should not detract clinicians from pursuing aggressive CV risk reduction, the application of evidence-based medicine specifically in patients with diabetes will facilitate the use of appropriate agents to improve clinical outcomes. The overall management of patients with diabetes and acute stroke or at risk of secondary stroke should also include multifactorial intervention that not only targets patient's CV risk but also includes behavioural, lifestyle and, where appropriate, surgical intervention.

100 or 30 years after Janeway or Bartter, Healthwatch helps avoid 'flying blind'

Longitudinal records of blood pressure (BP) and heart rate (HR) around the clock for days, weeks, months, years, and even decades obtained by manual self-measurements (during waking) and/or automatically by ambulatory monitoring reveal, in addition to well-known large within-day variation, also considerable day-to-day variability in most people, whether normotensive or hypertensive. As a first step, the circadian rhythm is considered along with gender differences and changes as a function of age to derive time-specified reference values (chronodesms), while reference values accumulate to also account for the circaseptan variation. Chronodesms serve for the interpretation of single measurements and of circadian and other rhythm parameters. Refined diagnoses can thus be obtained, namely MESOR-hypertension when the chronome-adjusted mean value (MESOR) of BP is above the upper limit of acceptability, excessive pulse pressure (EPP) when the difference in MESOR between the systolic (S) and diastolic (D) BP is too large, CHAT (circadian hyper-amplitude tension) when the circadian BP amplitude is excessive, DHRV (decreased heart rate variability) when the standard deviation (SD) of HR is below the acceptable range, and/or ecphasia when the overall high values recurring each day occur at an odd time (a condition also contributing to the risk associated with 'non-dipping'). A non-parametric approach consisting of a computer comparison of the subject's profile with the time-varying limits of acceptability further serves as a guide to optimize the efficacy of any needed treatment by timing its administration (chronotherapy) and selecting a treatment schedule best suited to normalize abnormal patterns in BP and/or HR. The merit of the proposed chronobiological approach to BP screening, diagnosis and therapy (chronotheranostics) is assessed in the light of outcome studies. Elevated risk associated with abnormal patterns of BP and/or HR variability, even when most if not all measurements lie within the range of acceptable values, becomes amenable to treatment as a critical step toward prevention (prehabilitation) to reduce the need for rehabilitation (the latter often after costly surgical intervention).

Sequential follow-up clinic and ambulatory blood pressure evaluation in a low risk population of white-coat hypertensive patients and in normotensives

BACKGROUND

In subjects with white-coat hypertension (WCH) it is unclear how ambulatory blood pressure (ABPM) progresses over time and whether they exhibit an increased cardiovascular risk.

METHODS

We prospectively evaluated the transition of clinic and ABPM values in 39 clinic and ABPM normotensive subjects (NT) (clinic BP<140/90 mmHg and awake BP<130/85 mmHg, ages 43.4+/-2.6 y) and in 79 untreated subjects (47.2+/-2.4 y) with WCH (clinic BP>140/90, awake ABP<130/85 mmHg) with no other major cardiovascular risk factors. Ambulatory blood pressure was evaluated at baseline and on at least two further occasions during follow-up.

RESULTS

At baseline all subjects were untreated and groups did not differ on values of metabolic parameters, BMI, left ventricular mass index, and ABPM values. Subjects were revaluated for ABPM half way through and at the end of follow-up, 35+/-3 and 86+/-4 months in NT and 49+/-4 and 90+/-4 months in WCH. Thirty-six WCH were on antihypertensive treatment (AH) after baseline until the end of follow-up (WCH-tr), whereas 43 WCH (WCH-untr) were free from AH throughout the study. In a similar way all groups showed a significant (p<0.01) progressive increase in 24-h ABPM systolic blood pressure (SBP)/diastolic blood pressure (DBP) from baseline throughout the follow-up in NT (+4.9/2.1+/-0.8/0.9 mmHg), average annual increase of 0.72/0.37 mmHg/y, in WCH-tr (+ 5.0/1.2+/-1.1/1.5 mmHg), average annual increase of 0.66/0.31 mmHg/y and in WCH-untr (+5.4/3.2+/-0.9/1.1 mmHg), average annual increase of 0.74/0.39 mmHg/y. During the follow-up office SBP/DBP (mmHg) significantly rose in NT (+5.7/3.9) but was reduced in WCH-tr (-7.8/5.2) and in WCH-untr (-4.7/1.1). Development of ambulatory hypertension (daytime BP >130 and/or >85 mmHg) occurred in 15.4% (6/39) of NT, in 22.7% (8/36) of WCH-tr and in 26.1% (11/43) of WCH-untr (NS). First cardiovascular events recorded were three in subjects with WCH and none in NT.

CONCLUSIONS

After 7.4 years of follow-up, both the progressive increase in ABPM and the rate of transition to ambulatory hypertension in subjects with WCH (either treated or untreated), who were selected under strict criteria were similar to that of normotensive subjects. Also there was no evidence that WCH exhibited a clear higher risk of development cardiovascular events.

Validation of the AGILIS ambulatory blood pressure monitor according to the European Society of Hypertension International Protocol for Validation of Blood Pressure Measuring Devices in Adults

BACKGROUND

We evaluated the clinical validity of the AGILIS ambulatory blood pressure monitor according to the European Society of Hypertension International Protocol.

METHODS

The blood pressure (BP) was measured at the same arm by two certified observers using two mercury columns and a double stethoscope, then by the volunteer with the automatic device, these measurements were done seven times sequentially using 33 volunteers. For the randomization of the patient, one ABPM measure was compared to the mean of three manual measures. Then, we had three ABPM measures and four manual measures. Each ABPM measure, being compared to two manual measures. Blood pressure readings and recordings were blinded. Position of the subjects was standardized.

RESULTS

Phase 1: To pass phase 1, the device had to have at least 25 of the 45 measurements within 5 mmHg, 35 within 10 mmHg or 40 within 15 mmHg of the comparative observer measurements. The AGILIS monitor had 35 measurements lying within 5 mmHg, 42 within 10 mmHg and 45 within 15 mmHg for systolic BP (SBP), 35 within 5 mmHg, 44 within 10 mmHg and 45 within 15 mmHg for diastolic BP (DBP). It passed the criteria for SBP and DBP. Phase 2: To pass phase 2.1, a device must have at least 60 of 99 measurements within 5 mmHg, 75 within 10 mmHg and 90 within 15 mmHg of the comparative observer measurements, and in addition must also have either 65 within 5 mmHg and 80 within 10 mmHg, or 65 within 5 mmHg and 95 within 15 mmHg, or 80 within 10 mmHg and 95 within 15 mmHg. The AGILIS monitor had 78 measurements within 5 mmHg, 91 within 10 mmHg and 96 within 15 mmHg for SBP; and 70 measurements within 5 mmHg, 92 within 10 mmHg and 96 within 15 mmHg for DBP. It passed the criteria for SBP and DBP. For phase 2.2 using the AGILIS monitor, 27 subjects had at least two of the differences within 5 mmHg and none had any differences within 5 mmHg for SBP; 27 subjects had at least two of the differences within 5 mmHg and three subjects had no differences within 5 mmHg for DBP. The results are in concordance with the requested criteria for phase 2.2.

CONCLUSION

Thus the AGILIS device fulfils the validation criteria of the international protocol.

Heritability of ambulatory and office blood pressure phenotypes in Swedish families

OBJECTIVE

The aim of this study was to estimate the heritability of 24-h ambulatory blood pressure and office blood pressure phenotypes in Swedish families.

METHODS

We measured ambulatory and office blood pressure in 260 siblings without antihypertensive treatment from 118 families. Blood pressure heritability was estimated using standard quantitative genetic variance component analysis implemented in the 'SOLAR' software package after adjustment for significant covariates.

RESULTS

Heritability values were significant for night-time systolic (37%), diastolic (32%) and mean (32%) ambulatory blood pressure (P < 0.05 for all). During daytime, systolic ambulatory blood pressure was significantly heritable (33%, P < 0.05). Twenty-four-hour systolic (30%) and diastolic (29%) ambulatory blood pressure also had significant values of heritability (P < 0.05). Pulse pressure ambulatory blood pressure was significantly heritable over 24 h (63%, P < 0.01), during daytime (53%, P < 0.01) and at night (34%, P < 0.05). None of the office blood pressure phenotypes had a significant heritability.

CONCLUSIONS

We conclude that ambulatory blood pressure, in particular at night, seems better than office blood pressure to capture the heritable part of blood pressure, suggesting that ambulatory blood pressure may be a more exact estimate of an individual's true blood pressure. Genetic studies using ambulatory blood pressure as the phenotype are likely to be more powerful than those using office blood pressure. The high heritability of pulse pressure ambulatory blood pressure indicates that variation in arterial stiffness in subjects free from antihypertensive medication is strongly affected by genetic factors.

Circadian time-qualified tolerance intervals for ambulatory blood pressure monitoring in the diagnosis of hypertension

The large-amplitude circadian pattern in blood pressure of healthy subjects of both genders suggests that the constant threshold currently used to diagnose hypertension should be replaced by a time-specified reference limit reflecting the mostly predictable blood pressure variability during the 24 h. Accordingly, we derived circadian time-specified reference standards for blood pressure as a function of gender. We studied 743 normotensive Caucasian volunteers (400 men and 343 women), 45.7 +/- 16.5 (mean +/- SD) years of age. Blood pressure was measured by ambulatory monitoring at 20-min intervals during the day and at 30-min intervals at night for 48 consecutive hours. Data from each blood pressure series were synchronized according to the rest-activity cycle of each individual in order to avoid differences among subjects in actual times of daily activity. Data were then used to compute 90% circadian tolerance intervals for each gender separately. The method, derived on the basis of bootstrap techniques, does not need to assume normality or symmetry in the data and, therefore, it is highly appropriate to describe the circadian pattern of blood pressure variability. Results reflect expected changes in the tolerance limits as a function of gender and circadian sampling time, as well as upper blood pressure limits below the thresholds currently used for diagnosing hypertension, especially for women. The use of these time-dependent tolerance limits for the computation of a hyperbaric index as a measure of blood pressure excess has already been shown to provide a reproducible and high-sensitivity test for the diagnosis of hypertension, which can also be used to evaluate treatment efficacy.

Strategies Against High Blood Pressure in the Early Morning

Acute myocardial infarction and cerebrovascular disease reportedly show peak onset in the early morning, when blood pressure increases. The increase of blood pressure, or morning surge, may result from increased sympathetic activity reactive to arousal. The circadian pattern of vascular events is considered to be related to the morning surge in blood pressure, sympathetic activity, and hypercoagulability. Although there is no direct evidence indicating a causal relationship between the morning surge in blood pressure and vascular complications, it may be postulated that morning blood pressure surge is a factor which affects hypertensive complications. There may be two possible approaches to morning blood pressure surge; the pharmacodynamic and pharmacokinetic approach. On the basis of pharmacodynamics, drugs with adrenergic alpha-blocking actions are usually selected. From a pharmacokinetic view, it is essential to maintain blood concentration of a drug at the critical early morning period. On this point, use of long acting agents, changes in drug regimen and the development of a chronobiological system has been studied, with many studies reporting successful results in lowering morning blood pressure. Further study whether such kinds of treatments improve long term outcomes in hypertensive patients are desired.

Clinical prediction of normotension in borderline hypertensive men ??? a 10 year study

OBJECTIVE

To investigate 24-h ambulatory blood pressure measurements (ABPM) as a tool for long-term prediction of future blood pressure (BP) status in high normal and low stage 1 hypertensives.

DESIGN, SETTING AND PARTICIPANTS

A total of 165 men from a population screening program with diastolic BP (DBP) 85-94 mmHg and a systolic BP (SBP) < 150 mmHg performed a 24-h ABPM. Ten years later, 120 participants (73%) returned for renewed measurements.

MAIN OUTCOME MEASURES

Blood pressure status at 10 years.

RESULTS

At the 10-year follow-up, 53% of the participants were classified as hypertensive (HT) (BP > or = 140/90 or taking anti-hypertensive medication) and 47% were classified as normotensive (NT) (BP < 140/90 mmHg). There was no significant baseline differences in office SBP levels between those who were normotensive or hypertensive at follow-up (136/91 versus 138/92 mmHg), whereas both SBP and DBP night-time levels were significantly lower in the future normotensives as compared to the future hypertensives (107/69 versus 112/74 mmHg, P < 0.01). Using recommended normalcy night-time ABP levels of < 120/75 mmHg in addition to office BP (140/90) at baseline, over 85% of the subjects were correctly classified provided they met both clinic and ambulatory night-time criteria for HT and NT classification at baseline.

CONCLUSION

The use of ABPM in addition to office BP's in patients with borderline hypertension greatly increases the possibility of identifying those individuals who are at a very small risk of developing future hypertension. This could potentially lead to considerable savings in both patient anxiety, physician time and resource consumption.

Continuous Recording of Blood Pressure in Cerebrovascular Disease: When Should It Be Done?

BACKGROUND AND OBJECTIVES

Ambulatory blood pressure (BP) monitoring has found some specific clinical indications in the treatment and control of hypertension (HT). As with other target organs exposed to vascular damage dependent on HT, ambulatory BP monitoring can be a useful tool in the prevention of cerebrovascular processes.

METHOD

Review of published articles (Medline database) which have investigated the value of continuous recording of BP in cerebrovascular disease (CVD).

RESULTS

Research on the BP patterns and its relationship with stroke has been carried out in subjects with no previous history of CVD (cohort studies and in patients with essential HT, differentiating between adults and elderly patients) and patients after a cerebral ischemic event. The study objectives are aimed at determining its prognostic value in the development of silent and symptomatic CVD, and its prognostic significance regarding functional recovery and the differences of the BP patterns according to the different stroke subtypes.

CONCLUSIONS

BP monitoring is a useful technique with applications in the control and treatment of the pathological variations of BP in hypertensive patients, with and without a previous history of cerebral ischemia, and mainly in elderly patients, due to the deterioration of the cerebral circulation regulation mechanisms. Clinical research has confirmed the importance of factors related to the circadian rhythm of BP in the primary and secondary prevention of cerebrovascular processes.

Ambulatory blood pressure measurement as a predictor of outcome in an Irish population: methodology for ascertaining mortality outcome

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) has proven to be a superior predictor of morbid events when compared to clinic or office blood pressure measurement (CBPM). The purpose of this study was to evaluate the predictive value of ABPM in a sample of 14 414 people referred for management of cardiovascular risk.

METHODS

In this paper we describe the methodology required to examine mortality outcome in the absence of a national unique identifier.

RESULTS

Using a computerized database of deaths we were able to establish that 1348 people had died by the end of the follow-up period (30 September 2002). Sixty-four percent of deaths were cardiovascular and in 207 subjects who had post-mortem examinations, 78% were cardiovascular.

CONCLUSIONS

The accurate identification of the cause of death in a large population will allow comparison of the relative predictive power of APBM and CBPM in an Irish population.

The telmisartan Programme of Research tO show Telmisartan End-organ proteCTION (PROTECTION) Programme

Angiotensin-II receptor blockers (ARBs) have been shown to provide stroke, cardiac and renal protection in high-risk hypertensive patients. Telmisartan is a powerful and selective ARB that provides sustained blood pressure reduction for a full 24 h after a single dose and continues to protect against circadian blood pressure surges in the critical early morning hours. The objective of the Programme of Research tO show Telmisartan End-organ proteCTION (PROTECTION) is to measure the end-organ protective effects of telmisartan in patients at high risk of renal, cardiac and vascular damage. An extensive series of clinical trials is being conducted to compare telmisartan with valsartan, losartan, amlodipine and ramipril in patients at increased risk of end-organ damage. Nine clinical studies will examine the effects of telmisartan in about 5000 hypertensive patients with isolated systolic hypertension, type 2 diabetes, obesity, left ventricular hypertrophy or renal disease. All of the studies will be conducted using state-of-the-art technology, including such techniques as ambulatory blood pressure monitoring and magnetic resonance imaging. This programme will also investigate the effects of an ARB on key surrogate markers of organ tissue damage. This series of trials will characterize the end-organ protective effects of telmisartan in hypertensive patient populations at high risk of clinical events.

Ambulatory blood pressure measurement is indispensable to good clinical practice

The traditional technique of blood pressure measurement is being phased out in most countries and is being replaced by automated measurement. The era of automated blood pressure measurement brings its own problems, not least being the need to evaluate blood pressure measuring devices independently for accuracy. Towards this end, the Working Group on Blood Pressure Monitoring of the European Society of Hypertension has published an international protocol with the aim of having all devices assessed for basic accuracy before being put on the market. The main thrust of this review is that if ambulatory blood pressure measurement has become indispensable to the management of patients with hypertension, it then becomes imperative to encourage the use of ambulatory blood pressure measurement (ABPM) in general practice rather than restricting its availability to specialist hospital centres. However, if ABPM is to be widely used in general practice, there is a need to establish appropriate educational processes and to improve the methods of presenting and analysing ABPM data.

Reduced nocturnal fall in blood pressure, assessed by two ambulatory blood pressure monitorings and cardiac alterations in early phases of untreated essential hypertension

To investigate whether in recently diagnosed essential hypertensives a reduced nocturnal fall in blood pressure (BP), established on the basis of two 24-h ambulatory blood pressure monitorings (ABPM) is related to a greater cardiovascular damage. In all, 355 consecutive, recently diagnosed, never-treated essential hypertensives referred for the first time to our outpatient clinic were included in the study. Each patient underwent the following procedures: (1) two 24-h ABPMs performed within 3 weeks, (2) 24-h urinary collection for microalbuminuria, (3) nonmydriatic photography of ocular fundi, (4) echocardiography, (5) carotid ultrasonography. We defined nondipping profile as a night-day systolic and diastolic fall < or =10 % (mean of two ABPMs). A dipper BP profile was found in 238 patients, whereas in 117 patients a nondipper profile was present. The two groups were similar for age, gender, body mass index, smoking habit, clinic BP, 48-h BP and heart rate, while, by definition, night-time systolic and diastolic BP were significantly higher in nondippers than in dippers (130/81 vs 121/74 mmHg, P < 0.0001).The prevalence of left ventricular hypertrophy (LVH) defined by four different criteria: (a) LV mass index (LVMI) > or = 125 g/m(2) in both genders; (b) LVMI > or = 134 gm(2) in men and > or = 110 in women; (c) LVMI> or = 125 g/m(2) in men and > or = 110 g/m(2) in women; (d) LVMI > or = 51 g/m(2.7) in men and > or = 47 g/m(2.7) in women was significantly higher in nondippers than in dippers (a: 12 vs 7%, P < 0.05; b: 16 vs 7%, P < 0.01; c: 20 vs 11%, P < 0.01; d: 35 vs 23% P < 0.02) and this finding was associated with a significant increase in aortic root and left atrium dimensions. There were no differences between the two groups in the prevalence of carotid and retinal changes and microalbuminuria. In conclusion our findings suggest that never-treated hypertensives with a reduced BP fall in the night time, defined on the basis of two ABPMs, have a higher prevalence of TOD than dippers, in terms of echocardiographic LVH. In this population setting, cardiac structural alterations are a more sensitive marker of the impact of the nocturnal BP load on cardiovascular system than other extracardiac signs of TOD.

[Behavior of the night decrease of arterial pressure after suppression controlled of the antihypertensive medication]

OBJECTIVE

The patients with hypertension who do not present a night decrease of the arterial pressure are a bigger degree of target organ damage due to the supported hypertension. In our work we analyzed after ambulatory blood pressure monitoring (ABPM) the prevalence of the condition dipper of the patients with hypertension of degree 1 and/or 2 after the suppression controlled of the antihypertensive medication; as well as the magnitude of the effect of white coat (object of another study).

DESIGN

Almost experimental study and descriptive.

SETTING

Primary care. Urban health centre. Participants measurements and results. Studies of ABPM were realized in 70 essential hypertense patients with good control of the arterial pressure after pharmacological treatment before suspending the antihypertensive medication (1 phase) and to the 4 weeks of leaving the treatment (2 phase), two periods being programmed: diurnal and night.

RESULTS

Of all 70 hypertense patients, 18 (26%) did not manage to carry out 2 ABPM since after the retreat of the medication there presented blood pressure unacceptable values that forced to re-introduce the medicaments. The 79% of the hypertense patients were dipper after the 1 monitoring and that after the suppression of the antihypertensive medication, 83% was continuing being dipper. Depending on the gender there were no statistically significant differences as for the night decrease of the arterial pressure in both periods. Finally, 75% and 11.5% of the patients were dippers or not dippers, respectively, in both phases and only 13.5% of the patients it changed its condition.

CONCLUSIONS

The retreat of the medication in hypertense of degree 1 and/or 2 well controlled does not modify the patients' percentage with night decreases of the blood pressure.

Blood pressure response to hyperventilation test reflects daytime pressor profile

Recent studies show that healthy subjects and patients with moderate hypertension have different pressor responses to hyperventilation, depending on their sympathoadrenergic reactivity. In the present study, we investigated whether a different response to the hyperventilation test is related to differences in the daily blood pressure profiles recorded with noninvasive ambulatory monitoring. Forty-five healthy subjects and 67 patients with essential hypertension of grades 1 and 2 (Joint National Committee VI and World Health Organization) were investigated. Healthy subjects and hypertensive patients responding to hyperventilation with an increase in systolic blood pressure had, during daytime ambulatory blood pressure assessment, peak systolic blood pressure values (146.0+/-5.0 mm Hg, 182.2+/-9.0 mm Hg, respectively) similar to the hyperventilation peak systolic blood pressure values (147.2+/-3.5 mm Hg, 183.0+/-4.7 mm Hg, respectively). Hypertensive patients responding to hyperventilation with a decrease in blood pressure showed clinic systolic blood pressure values (178.4+/-3.2 mm Hg) higher than daytime average ambulatory systolic blood pressure (155.2+/-7.1 mm Hg; P<0.01). Our results indicate that a hyperventilation test yields information on daily peak blood pressure values in healthy subjects and hypertensive patients when it induces a pressor increase and can identify hypertensive patients with the so-called "white coat effect" when it induces a pressor decrease.

Time-effect profile of antihypertensive agents assessed with trough/peak ratio, smoothness index and dose omission: an ambulatory blood pressure monitoring study with trandolapril vs. quinapril

The duration of action of antihypertensive drugs may be assessed by several methods using ambulatory blood pressure monitoring (ABPM). The aim of this double-blind, randomized study was to compare the time-effect profile of once daily Trandolapril (Tra) 2 mg vs. Quinapril (Qui) 20 mg in 92 patients with mild-to-moderate hypertension. All patients received placebo during a 30-day run-in period followed by 2 months of active therapy and 1-day medication omission. ABPM was conducted on each period. 24 h antihypertensive coverage was assessed by trough:peak ratio (T/P) and smoothness index (SI) methods. Residual lowering of blood pressure after single-blind, 1 day medication omission was investigated as the SBP/DBP 48-h trough effect. There were no statistically significant differences between treatment groups in the mean SBP/DBP peak or trough effect. Individual T/P were not normally distributed and had very large variations explained by BP random- and activity-related fluctuations. Group T/P were 0.85 for Tra and 0.62 for Qui. The SI values were normally distributed and not statistically different between the two treatment groups. After dose omission, Qui was ineffective at 48-h trough while Tra retained a significant effect (SBP/DBP = -3.4/-4.3 mmHg) and this difference was even greater in ABPM-responders. Comparison of the trough:peak ratios and smoothness indexes of Tra and Qui failed to show any statistically significant difference on 24-h antihypertensive coverage. Nevertheless, residual lowering of blood pressure at 48-h trough suggests that Tra had a longer duration of action than Qui.

The tolerance-hyperbaric test: a chronobiologic approach for improved diagnosis of hypertension

Blood pressure (BP) displays predictable large-amplitude circadian variability. Thus, the identification and the proper definition of hypertension are highly ambiguous when based on single time-unspecified measurements. One way to deal with such variability in the diagnosis of hypertension is to replace the commonly used constant limits of BP by a time-specified reference interval based on the normal circadian BP rhythm assessed by ambulatory BP monitoring (ABPM). A proper reference limit can be constructed, for instance, as a tolerance interval computed for every specific time interval throughout the 24 h. Once such a threshold (given by the upper limit of the tolerance interval) is constructed, a hyperbaric index (HBI) can be computed by numerical integration of the total area of any given patient's BP profile above threshold. The HBI plus the duration of excess within the 24h day serves as nonparametric endpoints for assessing hypertension. Both retrospective and prospective evaluation of this tolerance-hyperbaric test validate its high sensitivity and specificity in the diagnosis of hypertension. We describe the theory of the HBI as well as a newly created dedicated software program that automatically derives the tolerance intervals from a reference database of normotensive subjects and calculates the HBI and other potentially valuable parameters based on data obtained by ABPM. The establishment of time-qualified tolerance limits and the assessment of the extent and timing of BP elevation represents a valuable tool for the more accurate diagnosis of hypertension as well as means of gauging response to treatment.

[Effect of environmental stress on blood pressure during the work shift]

OBJECTIVE

To evaluate blood pressure (BP) and heart rate (HR) behavior in individuals during the working journey in two environments with different work stressors.

METHODS

The study comprised 46 male individuals working in a wood processing factory in Botucatu, Brazil. Twenty seven (27.4+/-5.4 yrs, mean+/-SD) worked in the production line performing intense physical activity (G1) at high room temperatures and noise levels. Nineteen (33.2+/-7.6 yrs old) performed managerial tasks mostly comfortably seated at low noise, air-conditioned offices (G2). After anthropometric measurements (obesity, total and local adiposity) and blood biochemistry analyses (glucose, triglycerides and cholesterol), their BP and HR were registered during three consecutive days at 3 different time of the day: in the beginning, in the middle and at the end of the working journey.

RESULTS

There were similar BP and HR changes during the journey for G1 and G2, but G1 showed higher rates. Due to the wide variability of BP responses within each group, participants were divided in two subgroups: responders (GR1 and GR2) with BP increase >10%, and non-responders (GN1 and GN2). Both subgroups showed similar anthropometric and biochemical patterns differing only in their BP response and, in the case of GR1,family history for hypertension. GR1 showed higher BP and HR than GR2.

CONCLUSIONS

Individual changes of BP and HR responses to environmental stressors during the working journey indicates that these factors should be considered while evaluating BP measurements and might be considered as potential factors for hypertension.