Twenty-four hour blood pressure monitoring in the Syst-Eur trial

Correlation between the severity of apnea and hypopnea sleep, hypertension and serum lipid and glycemic: a case control study

The purpose of this study was to evaluate the correlation between the severity of obstructive sleep apnea (OSA) and the levels of blood pressure (BP), lipids and glucose, as intermittent hypoxia increases BP, changes the oxidative balance, and can induce the formation of free radicals and atherogenesis. 32 patients were evaluated about BP during wakefulness and sleep, total cholesterol and lipids, LDL (low-density lipoprotein), HDL (high-density lipoprotein), triglycerides, glucose and polysomnography. They were divided into four groups according to the respiratory events per hour of sleep (RDI): control group (RDI < 5), Group I (RDI 5–15), Group II (RDI 15–30), Group III (RDI > 30). There was no increase in BP in groups’ cases, the verification of systolic (p = 0.429) and diastolic (p = 0.475) BP in 24 h, systolic (p = 0.277) and diastolic (p = 0.143) BP during wakefulness, and systolic (p = 0.394) and diastolic (p = 0.703) BP during sleep in the control group. When implementing the Spearman correlation test, a correlation directly proportional to the severity of the disease was not observed. Regarding the level of serum total cholesterol (p = 0.092), LDL (p = 0.242), HDL (p = 0.517), triglycerides (p = 0.947), total lipids (p = 0.602) and glucose (0.355), there was no statistically significant difference between groups (p > 0.05 for all parameters). There is no correlation between the severity of OSA and BP levels in 24 h, during daytime, during the sleep and serum levels of LDL and HDL cholesterol.

Systolic blood pressure variability as a risk factor for stroke and cardiovascular mortality in the elderly hypertensive population

OBJECTIVE

To investigate whether baseline systolic blood pressure variability was a risk factor for stroke, cardiovascular mortality or cardiac events during the Syst-Eur trial.

DESIGN

The Syst-Eur study was a randomized, double-blind, placebo-controlled trial, powered to detect differences in stroke rate between participants on active antihypertensive treatment and placebo. Systolic blood pressure variability measurements were made on 744 participants at the start of the trial. Systolic blood pressure variability was calculated over three time frames: 24 h, daytime and night-time. The placebo and active treatment subgroups were analysed separately using an intention-to-treat principle, adjusting for confounding factors using a multiple Cox regression model.

PARTICIPANTS

An elderly hypertensive European population.

MAIN OUTCOME MEASURES

Stroke, cardiac events (fatal and non-fatal heart failure, fatal and non-fatal myocardial infarction and sudden death) and cardiovascular mortality (death attributed to stroke, heart failure, myocardial infarction, sudden death, pulmonary embolus, peripheral vascular disease and aortic dissection).

RESULTS

The risk of stroke increased by 80% (95% confidence interval: 17-176%) for every 5 mmHg increase in night-time systolic blood pressure variability in the placebo group. Risk of cardiovascular mortality and cardiac events was not significantly altered. Daytime variability readings did not predict outcome. Antihypertensive treatment did not affect systolic blood pressure variability over the median 4.4-year follow-up.

CONCLUSION

In the placebo group, but not the active treatment group, increased night-time systolic blood pressure variability on admission to the Syst-Eur trial was an independent risk factor for stroke during the trial.

Relationship between ambulatory blood pressure and follow-up clinic blood pressure in elderly patients with systolic hypertension

BACKGROUND

Patients with elevated clinic blood pressure and normal ambulatory blood pressure have a better prognosis than patients with sustained ambulatory hypertension, and may not have to be treated with antihypertensive drugs. On the contrary, current guidelines emphasize repeated clinic blood pressure measurements for the initiation of antihypertensive therapy.

OBJECTIVE

To examine the relationship between ambulatory blood pressure at baseline and clinic blood pressure after 6 months of follow-up in untreated hypertensive patients, and the relationships of these pressures with the subsequent incidence of cardiovascular events.

METHODS

Patients who were > or = 60 years old, with systolic clinic blood pressure of 160-219 mmHg and diastolic pressure < 95 mmHg, participated in the Systolic Hypertension in Europe trial. The relationship between ambulatory blood pressure at baseline and clinic blood pressure after 6 months of follow-up was examined in 295 patients enrolled in the Ambulatory Blood Pressure Monitoring substudy and randomized to the placebo arm, and who were still on double-blind treatment and not taking other antihypertensive drugs after 6 months follow-up.

RESULTS

Age averaged 70 +/- 6 years, 41% were men, and baseline daytime ambulatory blood pressure was 152 +/- 16/84 +/- 10 mmHg; clinic blood pressure decreased from 173 +/- 10/86 +/- 6 mmHg at baseline to 163 +/- 20/85 +/- 9 mmHg at month 6. Systolic daytime ambulatory blood pressure at baseline and systolic clinic blood pressure at month 6 were considered normal if < 140 mmHg. Of the 74 patients with normal systolic daytime ambulatory blood pressure at baseline, only seven (9.5%) had a normal systolic clinic blood pressure during follow-up. Conversely, of the 24 patients with normal follow-up clinic blood pressure, only seven (29%) had a normal systolic daytime ambulatory blood pressure at baseline. The incidence of cardiovascular events beyond the 6-month visit was significantly related to baseline ambulatory blood pressure but not to follow-up clinic pressure.

CONCLUSIONS

Baseline daytime ambulatory blood pressure and follow-up clinic blood pressure do not identify the same patients for antihypertensive treatment. Baseline ambulatory pressure is a better predictor of cardiovascular events than follow-up clinic pressure.

Risk and benefit of treatment of isolated systolic hypertension in the elderly: evidence from the Systolic Hypertension in Europe Trial

The Syst-Eur trial investigated whether active treatment starting with the dihydropyridine calcium channel blocker (CCB) nitrendipine, could reduce the cardiovascular complications of isolated systolic hypertension (ISH) in the elderly. The intention-to-treat analysis showed that active treatment improved outcome. The per-protocol analysis largely confirmed these results. The effect of treatment on total and cardiovascular mortality might be attenuated in very old patients. Further analysis also suggested benefit in those patients who remained on nitrendipine monotherapy. Active treatment was more beneficial in patients with diabetes as compared with those without diabetes at entry and reduced the incidence of dementia by 50%. Analyses of data from the Ambulatory Blood Pressure Monitoring (ABPM) Side Project suggested that most of the benefit of treatment was seen in patients with a daytime systolic BP > or = 160 mm Hg. Finally, a meta-analysis partly based on Syst-Eur data showed that in older hypertensive patients pulse pressure and not mean pressure is the major determinant of cardiovascular risk.

Response to antihypertensive therapy in older patients with sustained and nonsustained systolic hypertension. Systolic Hypertension in Europe (Syst-Eur) Trial Investigators

BACKGROUND

The goal of the present study was to assess the effect of antihypertensive therapy on clinic (CBP) and ambulatory (ABP) blood pressures, on ECG voltages, and on the incidence of stroke and cardiovascular events in older patients with sustained and nonsustained systolic hypertension.

METHODS AND RESULTS

Patients who were >/=60 years old, with systolic CBP of 160 to 219 mm Hg and diastolic CBP of <95 mm Hg, were randomized into the double-blind placebo-controlled Systolic Hypertension in Europe (Syst-Eur) Trial. Treatment consisted of nitrendipine, with the possible addition of enalapril, hydrochlorothiazide, or both. Patients enrolled in the Ambulatory Blood Pressure Monitoring Side Project were classified according to daytime systolic ABP into 1 of 3 subgroups: nonsustained hypertension (<140 mm Hg), mild sustained hypertension (140 to 159 mm Hg), and moderate sustained hypertension (>/=160 mm Hg). At baseline, patients with nonsustained hypertension had smaller ECG voltages (P<0.001) and, during follow-up, a lower incidence of stroke (P<0.05) and of cardiovascular complications (P=0.01) than other groups. Active treatment reduced ABP and CBP in patients with sustained hypertension but only CBP in patients with nonsustained hypertension (P<0.001). The influence of active treatment on ECG voltages (P<0.05) and on the incidence of stroke (P<0.05) and cardiovascular events (P=0.06) was more favorable than that of placebo only in patients with moderate sustained hypertension.

CONCLUSIONS

Patients with sustained hypertension had higher ECG voltages and rates of cardiovascular complications than did patients with nonsustained hypertension. The favorable effects of active treatment on these outcomes were only statistically significant in patients with moderate sustained hypertension.

Modern approaches to blood pressure measurement

BACKGROUND

Blood pressure (BP) is usually measured by conventional sphygmomanometry. Although apparently simple, this procedure is fraught with many potential sources of error. This review focuses on two alternative techniques of BP measurement: ambulatory monitoring and self measurement.

REVIEW

BP values obtained by ambulatory monitoring or self measurement are characterised by high reproducibility, are not subject to digit preference or observer bias, and minimise the transient rise of the blood pressure in response to the surroundings of the clinic or the presence of the observer, the so called white coat effect. For ambulatory monitoring, the upper limits of systolic/diastolic normotension in adults include 130/80 mm Hg for the 24 hour BP and 135/85 and 120/70 mm Hg for the daytime BP and night time BP, respectively. For the the self measured BP these thresholds include 135/85 mm Hg. Automated BP measurement is most useful to identify patients with white coat hypertension. Whether or not white coat hypertension predisposes to sustained hypertension remains debated. However, outcome is better correlated with the ambulatory BP than with the conventional BP. In patients with white coat hypertension, antihypertensive drugs lower the BP in the clinic, but not the ambulatory BP, and also do not improve prognosis. Ambulatory BP monitoring is also better than conventional BP measurement in assessing the effects of treatment. Ambulatory BP monitoring is necessary to diagnose nocturnal hypertension and is especially indicated in patients with borderline hypertension, elderly patients, pregnant women, patients with treatment resistant hypertension, and also in patients with symptoms suggestive of hypotension.

CONCLUSIONS

The newer techniques of BP measurement are now well established in clinical research, for diagnosis in clinical practice, and will increasingly make their appearance in occupational and environmental medicine.

Antihypertensive effects of combined lisinopril and hydrochlorothiazide in elderly patients with systodiastolic or systolic hypertension: results of a multicenter trial

This study was aimed at evaluating the antihypertensive effect of lisinopril and hydrochlorothiazide administered in the fixed combination of 20 and 12.5 mg, respectively, on clinic and 24-h blood pressure in elderly patients (age, 68.8 +/- 5.8 years, mean +/- SD) with mild-to-moderate essential systodiastolic or isolated systolic hypertension. After a washout period of 4 weeks, patients received once daily lisinopril combined with hydrochlorothiazide for a 6-week period. At the end of the washout and treatment periods, clinic blood pressure was assessed 24 h after dosing, and 24-h ambulatory blood pressure was monitored, taking blood pressure readings every 15 min. Pretreatment clinic blood pressure was 171.3 +/- 14.0/103.7 +/- 5.1 mm Hg (systolic/diastolic) in the group with systodiastolic hypertension (n = 405) and 179.6 +/- 9.4/83.6 +/- 5.4 mm Hg in the group with isolated systolic hypertension (n = 165). The corresponding 24-h average blood pressures were 144.1 +/- 13.9/88.7 +/- 8.4 mm Hg (n = 114) and 150.7 +/- 15.5/80.8 +/- 9.4 mm Hg (n = 40). Clinic blood pressure was significantly reduced by treatment in both groups. This was the case also for ambulatory blood pressure, which was reduced by 9.6 +/- 0.9%/9.9 +/- 0.9% in systodiastolic and by 11.8 +/- 1.3%/8.5 +/- 1.5% in isolated patients with systolic hypertension (p < 0.05 at least for all differences). The antihypertensive effect was similar in patients older and younger than 70 years. In all groups, it was manifest both during the day and the nighttime and was still significant after 24 h. Thus single daily administration of combined lisinopril-hydrochlorothiazide effectively reduces blood pressure in elderly patients with hypertension.

Optimizing the assessment of the elderly patient with borderline hypertension: the Hypertension and Ambulatory Recording in the OLD (HAROLD) study

This article describes the objectives and protocol of the HAROLD study, a trial designed to assess whether home blood pressure (BP), 24-hour ambulatory BP, left ventricular structure and function, and albumin excretion rate are more accurate predictors of outcome than traditional sphygmomanometric BP in elderly subjects with borderline hypertension. Development of sustained hypertension (BP > or = 160/95 mmHg) and incidence of morbid events over a 5-year follow-up are considered soft and hard endpoints, respectively. Patients with blood pressure values between 140/90 and 159/94 mmHg after three months of observation and who have never been treated, are eligible for the study; these subjects must be 60 to 79 years old, and free from other important risk factors for atherosclerosis. Baseline exams, which include plasma renin and insulin, 24-hour urine collection for detection of microalbuminuria, and echo-doppler cardiac examination are repeated after three and five years follow-up, or when subjects develop sustained hypertension. To recruit a large enough number of subjects to allow a sufficient number of endpoints (over 1000 subjects), the study is conducted as a multicenter trial. Ninety Italian Hospital Centers have agreed to participate in the study.

State of the market. A review of ambulatory blood pressure monitoring devices

The introduction of 24-hour ambulatory blood pressure measurement into clinical practice created a large market for ambulatory blood pressure measurement devices. Forty-three such devices from 31 manufacturers or suppliers are now available to satisfy a market demand that is likely to increase. The aim of this article is to identify the devices available and then to examine critically any validation studies assessing accuracy and performance. Of the 43 devices available 18 have been validated according to the protocols of the Association for the Advancement of Medical Instrumentation (AAMI) or the British Hypertension Society (BHS) in 25 reported studies. In 9 of these studies the protocol was not adhered to, and the results, which are therefore questionable, are noted but not considered further. Fourteen devices were evaluated according to the accuracy criteria of both protocols, and of these 9 fulfilled the requirements. From this review of 43 devices on the market it may be concluded that, at the time of writing, there is published evidence for only 9 devices meeting the generally accepted AAMI and BHS criteria for accuracy and performance; these are the A&D TM-2420 models 6 and 7 and TM-2421, CH-Druck, Nissei ABPM DS-240, Profilomat, QuietTrak, and SpaceLabs SL-90202 and SL-90207.

Blood pressure variability and reflex control in the elderly

Several lines of experimental and clinical evidence collected over the past ten years suggest that the aging process is characterized not only by profound structural cardiovascular alterations, but also by marked functional changes in the reflex mechanisms involved in the homeostatic control of the circulation. This paper will examine how aging affects baroreceptor control of the heart and sympathetic nerve traffic, providing evidence that while the former is markedly impaired in the elderly, the latter is virtually preserved. It will also discuss the age-related alterations in cardiopulmonary receptor function that, under physiological conditions, tonically inhibit sympathetic vasoconstriction tone and renin release from the kidney. Finally, evidence will be provided showing that short- and long-term blood pressure variabilities (and the different components of blood pressure variability) over 24 hours undergo major changes in the elderly. All these alterations in neural cardiovascular control mechanisms have clearcut clinical implications representing a potential marker of the increased cardiovascular risk which characterizes elderly people.

Evaluation of blood pressure measuring devices

Validation of blood pressure measuring devices is a relatively new field of research. There are two national protocols for validating blood pressure measuring devices: the protocol of the American Association for the Advancement of Medical Instrumentation (AAMI) and the protocol of the British Hypertension Society (BHS), each of which has recently been revised. 19 blood pressure measuring devices have been validated according to one or both of these protocols. These protocols have been beneficial in drawing attention to the potential inaccuracy of blood pressure measuring systems, they permit comparison between devices and they have brought manufacturers of blood pressure measuring devices into closer contact with the profession. There are some inherent weaknesses in both protocols which include the fallibility of the 'gold standard', the lack of provision for validation in special circumstances and in special groups, such as the elderly and pregnant women, and failure to allow for deteriorating accuracy with higher pressure levels. The revised BHS protocol attempts to redress these deficiencies.

Ambulatory blood pressure monitoring in hypertension

Ambulatory blood pressure monitoring generates a greater interest among investigators and clinicians because of its potential to 1) study the mechanisms involved in cardiovascular control in daily life (particularly if monitoring is performed on a beat-to-beat basis) and 2) improve the diagnosis of hypertension, the estimate of the patient's risk and the assessment of the efficacy of antihypertensive treatment. This paper will discuss the evidence pros and cons the latter indications of this approach. It will be shown that 24 hour blood pressure values correlate more closely than clinic blood pressure with various measures of the end organ damage of hypertension, suggesting that it may reflect better than traditional blood pressure measurements the cardiovascular consequences of this condition. Wider use of ambulatory blood pressure monitoring in the medical practice, however, must await a more clear demonstration of its prognostic importance, by longitudinal studies based on cardiovascular morbidity and mortality or on surrogate end points with undisputable clinical significance (e.g. left ventricular hypertrophy). It must also await clear definition of ambulatory blood pressure normality based on population studies. Until then ambulatory blood pressure monitoring should be employed to resolve special problems, e.g. identification of white coat hypertension and false non response to treatment.