Self monitoring versus ambulatory blood pressure monitoring]

Blood pressure is a variable parameter for which the isolated determination cannot be considered as a characteristic of the subject. Therefore, the clinical measurement of blood pressure constitutes the method of reference but presents limits and causes of errors which pose a problem for its validity in evaluating the average blood pressure level in certain patients. In order to overcome the limits of occasional measurement, different methods of blood pressure measurement have been proposed. Among these methods, self monitoring of blood pressure by the patient and 24 hour ambulatory blood pressure monitoring (ABPM) are the most used. Each of these methods presents advantages and disadvantages, indications and limits of use. The information obtained by each of them is of a different nature: these methods are not substitutes but are complementary. Self monitoring and ABPM seem to evaluate the pressure load better than clinical monitoring and are better correlated to the organic effects of hypertension and thus the cardiovascular morbidity and mortality, ABPM in particular. However, it remains to be clarified whether the use of these methods in the evaluation of cardiovascular risk and the therapeutic management of the hypertensive can improve the long term cardiovascular prognosis.     

Assessment of antihypertensive efficacy by non-invasive ambulatory blood pressure monitoring

The session devoted to the usefulness of non-invasive ambulatory blood pressure monitoring (ABPM) in the evaluation of antihypertensive therapy allowed us to discuss a number of important issues. ABPM emerged as a widely accepted technique to measure blood pressure in clinical trials. Actually, it was generally considered to provide more valuable information than do conventional blood pressure readings obtained sporadically by a doctor. However, still debated was the way of analysing ABPM recordings. This was particularly true with respect to the proposal of considering separately responders and non-responders when assessing the quality of blood pressure control achieved during treatment.     

The usefulness and limits of the ambulatory monitoring of arterial pressure

The interpretation of blood pressure values, measured by the physician in the medical environment, has some limitations. Blood pressure fluctuates considerably due to circadian rhythm and various environmental stimuli and thus casual readings may not be representative of the true blood pressure status of the patient. Non-invasive ambulatory blood pressure monitoring has greatly increased our knowledge regarding the diagnosis, treatment efficacy, natural history and even prognosis of hypertension. This technique allows the evaluation of repeated blood pressure measurements at given times (daytime, nighttime, early-morning) and in different conditions (awake, asleep, at rest, during physical or mental activity etc.). Many studies have shown that the whole-day values obtained with such devices correlate better with the morbidity and mortality associated with hypertension than does casual office blood pressure. The 24-hour blood pressure recording is useful in the diagnosis of hypertension, particularly to discriminate so called white coat hypertension (for which the term isolated clinic hypertension has recently been proposed). Ambulatory blood pressure monitoring provides reliable and detailed information on the efficacy of pharmacological treatment and its ability to cover the whole day. These considerations notwithstanding, the application of this technique is still far from routine in the clinical management of arterial hypertension. Its major limit is that the normalcy of ambulatory blood pressure values still remains to be calculated, and only hypothetical normal reference values, derived from studies of selected normotensive populations, are presently available.     

The placebo effect in ambulatory blood pressure monitoring

The reduction of clinic blood pressure by placebo tablets in clinical trials of antihypertensive drugs is well established and health authorities require a placebo arm in these trials in order to know how much of the total reduction of blood pressure is attributable to the drug. Most authors now favor the hypothesis that, in contrast to clinic blood pressure measurements, ambulatory blood pressure monitoring (ABPM) is not subject to a placebo effect. Scientific evidence so far shows that ABPM recordings are affected by a negligible and clinically irrelevant placebo effect in short-term trials. Nevertheless, the results of the SYST-EUR study suggest that placebo treatment induces a reduction of blood pressure in old patients with isolated systolic hypertension even when blood pressure is measured by 24 h ABPM, and raise the question of whether a placebo arm is required in clinical trials when ABPM is used to measure changes in blood pressure. In this article, the evidence supporting and contradicting the hypothesis that placebo exerts an effect on ABPM and the possible explanations for the discrepancy are reviewed. My position is that clinical trials on antihypertensive drugs using ABPM should be designed with the same standards as those using clinic blood pressure measurements; that is, randomized, double-blind, placebo-controlled studies. This should be an absolute requirement in long-term trials. Short-term trials lasting no more than 12 weeks, particularly those focused on examining average changes in 24 h diastolic blood pressure, may be designed without a placebo arm.     

Evaluation of the antihypertensive effect of celiprolol by ambulatory blood pressure monitoring

The use of ambulatory blood pressure monitoring has gained popularity because it is not subject to those limitations associated with traditional sphygmomanometry (inaccuracy of blood pressure readings, low number of readings, and failure to represent daytime blood pressure readings). In the present study, we provide evidence that the 24-hour mean blood pressure obtained through intraarterial blood pressure measurements in ambulatory patients provides a more accurate diagnosis (and perhaps a prognosis) of hypertension than that provided by cuff-obtained casual blood pressure measurement. Furthermore, despite a reduction in the amount and in the accuracy of the information obtained, blood pressure data provided by noninvasive blood pressure monitoring are also more accurate diagnostically than cuff-obtained casual blood pressure measurements. In 15 essential hypertensive patients in whom celiprolol, 400 mg once daily, was compared with placebo in a randomized double-blind crossover study, the use of noninvasive 24-hour automatic blood pressure monitoring showed that in responsive patients, celiprolol induced a sustained reduction in systolic and diastolic blood pressure throughout the 24 hours. The blood pressure reduction was also apparent during the night, despite the concomitant occurrence of a slight tachycardia. These findings demonstrate that once-daily administration of celiprolol provides an effective lowering of the 24-hour blood pressure profile. This dosing schedule can therefore be regarded as appropriate for antihypertensive therapy.     

Doppler echocardiographic study of arterial distensibility. Comparison with ambulatory arterial pressure monitoring

Echocardiography Doppler (ED) is a common tool in hypertension to assess left ventricular (LV) mass or LV function. Echography doppler is also available to assess some arterial distensibility (AD) indexes, but it is less frequently used. The aim of this study is to compare AD indexes obtained from échographie doppler with timing of Korotkoff sound (QKd interval), obtained from ambulatory blood pressure monitoring (APM). Sixty-two patients with or without cardiac diseases were prospectively enrolled, except those with left bundle branch, atrial fibrillation or pacemaker. Echography doppler study collected timing of abdominal pulse (QtAA), interval time between Q ECG and the foot of doppler wave velocity in abdominal aorta pulse wave velocity (PWV) between two points of descending thoracic aorta; and Stroke index. APM study collected simultaneous usual pressure indexes (systolic diastolic, pulse pressure) instantaneous and over 24 h, and QKd interval times between Q ECG and diastolic Korotkoff sound instantaneous and over 24 h. Absolute AD Index (Burton index) was defined as Stroke index/pulse pressure. QtAA intra observer variability was the coefficient of variation (mean/SD). QtAA inter observer variability was QtAA assessments by two observers. RESULTS: QtAA was correlated with QKdi (r = 0.78; p < 0.001) and QKd24 h (r = 0.64; p < 0.001). PWV was correlated with QKdi (r = 0.35; p = 0.009), but not with QKd24 h (r = 0.17; p = 0.24, NS). Burton index was correlated with QKdi (r = 0.48; p < 0.001), and QKd24 h (r = 0.53; p < 0.001). CONCLUSION: Echography doppler may provide some arterial distensibility indexes. Among these indexes, QtAA is easy to obtain and well correlated with QKd. However, further studies are needed to assess normal and pathological values.     

24小时动态血压监测厄贝沙坦降压效果

目的　评价24小时动态血压监测(ABPM)厄贝沙坦降压效果。　方法　选择1级至2级原发性高血压患者45例给予厄贝沙坦150mg每日一次,早晨7∶00口服,共4周。ABPM用药前后24小时血压变化情况。　结果　厄贝沙坦治疗后24小时血压显著下降(P<005),总有效率为82%,白天与夜间血压下降幅度大致相同,保持正常血压昼夜节律变化。　结论　厄贝沙坦对1~2级高血压是较为理想的药物。     

Assessment of patients with office hypertension by 24-hour noninvasive ambulatory blood pressure monitoring

To assess the discrepancy between casual (office) and home blood pressure readings in patients performing home blood pressure monitoring, we analyzed office, home, and 24-hour ambulatory blood pressure and heart rates in 19 patients in a prospective four-week study. After the month of study, the average difference between mean office and manual home blood pressures in this office hypertensive group was 30 +/- 17/20 +/- 6 mm Hg. The blood pressures taken in the office were substantially greater than the 24-hour average blood pressures and ambulatory blood pressures during work or while at home (awake). An analysis of the automatic monitor readings while in the doctor's office and at 15-minute intervals after leaving the office showed a progressive reduction in blood pressure and heart rate during the first hour after leaving the office. A mean 24-hour blood pressure of less than 130/80 mm Hg was found in 13 (68%) patients. These data suggest that patients with office hypertension are usually normotensive but may have a persistent and recurrent pressor response in a medical care setting. Ambulatory blood pressure monitoring provides confirmation of not only the office-home disparity, but also suggests that stress other than office visits fails to elicit a hypertensive response.     

Ambulatory arterial stiffness index derived from 24-hour ambulatory blood pressure monitoring

We hypothesized that 1 minus the slope of diastolic on systolic pressure during 24-hour ambulatory monitoring (ambulatory arterial stiffness index [AASI]) might reflect arterial stiffness. We compared AASI with established measures of arterial stiffness and studied its distribution in Chinese and European populations. We used 90207 SpaceLabs monitors and the SphygmoCor device to measure AASI, central and peripheral pulse pressures, the central (CAIx) and peripheral (PAIx) systolic augmentation indexes, and aortic pulse wave velocity. In 166 volunteers, the correlation coefficient between AASI and pulse wave velocity was 0.51 (P<0.0001). In 348 randomly recruited Chinese subjects, AASI correlated (P<0.0001) with CAIx (r=0.48), PAIx (r=0.50), and central pulse pressure (r=0.50). AASI increased with age and mean arterial pressure but decreased with body height. Both before and after adjustment for arterial wave reflections by considering height and heart rate as covariates, AASI correlated more (P<0.0001) closely with CAIx and PAIx than 24-hour pulse pressure. Among normotensive subjects, the 95th percentile of AASI was 0.55 in Chinese and 0.57 in 1617 Europeans enrolled in the International Database on Ambulatory Blood Pressure Monitoring. The upper boundary of the 95% prediction interval of AASI in relation to age ranged from 0.53 at 20 years to 0.72 at 80 years. In conclusion, AASI is a new index of arterial stiffness that can be easily measured under ambulatory conditions. Pending additional validation in outcome studies, normal values of AASI are probably <0.50 and 0.70 in young and older subjects, respectively.     

动态血压监测评价吲哒帕胺新型缓释片的降压作用

目的　评价吲哒帕胺 (商品名纳催离 ,法国施维雅药厂生产 ) 1 5mg缓释片的长效降压效果及安全性。方法　 3个中心收治的 10 8例轻、中度高血压病患者 [男 5 9例 ,女 4 9例 ,平均年龄 (5 1± 11)岁 ]服安慰剂 2周后及服吲哒帕胺 1 5mg缓释片 8周后 ,分别于早晨 8:0 0来医院佩带 2 4h动态血压监测仪 ,进行连续 30h动态血压测定 ,计算谷峰比值 (T/P)及每小时平均血压 ,同时在服吲哒帕胺1 5mg缓释片的第 2、4、8周在诊所测坐位血压。药物安全性主要观察血钾及血尿酸。结果　 10 8例轻、中度高血压患者服药后通过诊所测坐位血压评价 ,降压总有效率为 6 7 6 % ;2 4h动态血压监测结果按全部患者计算或有效病例计算 ,T/P比值结果相近。全组计算收缩压 (SBP)与舒张压 (DBP)的T/P比值分别为 0 80和 0 79。服缓释片与服安慰剂后第 2 5～ 30h动态血压监测发现 ,血压分别为 (134± 12 ) /(89± 9)mmHg (1mmHg =0 133kPa)及 (14 2± 12 ) / (92± 7)mmHg(P <0 0 1)。对 2 4h动态血压最大降压幅度≥ 2 0 / 10mmHg的 33例有反应者 ,分析其最大降压时间 ,93%在 8～ 19h,其中 14～ 17h为最高峰。服药后出现轻度低血钾 8例 (7 4 % ) ,仅 1例血钾 <3 0mmol/L(2 94mmol/L) ;血尿酸轻度升高者 18例(16 7% )。结论　吲哒     

Assessment of nocturnal hypertension by ambulatory blood pressure monitoring at the forearm in people with morbid obesity

Blood pressure (BP) measurement at the forearm (FA) has been proposed as alternative site to upper arm (UA) in people with morbid obesity (MO). We compared nocturnal BP readings simultaneously taken at FA and UA by ambulatory blood pressure monitoring (ABPM). Fourteen individuals with MO and seven normal‐weight controls underwent nocturnal ABPM with two devices placed at the UA and contralateral FA, respectively. Agreement between FA‐UA BP, diagnosis of nocturnal hypertension, and potential determinants of BP differences were evaluated. BP at the FA was significantly higher than UA in both people with MO and controls. FA‐UA differences in systolic and diastolic BP were similar in people with MO and controls. Nocturnal hypertension was diagnosed in 10 subjects (48%) according to UA BP and in 13 subjects (62%) according to FA BP (concordance 76%, moderate agreement). ΔFA‐UA systolic BP was associated with ratio between FA/UA circumferences (R = 0.45, P < .05) and with cuff‐UA slant angle difference (R = 0.44, P < .05). In conclusions, in people with MO, the agreement between FA and UA nighttime BP measured by ABPM is sub‐optimal. Our results raise uncertainty in using ABPM at the FA as an alternative to UA placement in people with MO for the diagnosis of nocturnal hypertension.     

Assessment of arterial stiffness from ambulatory blood pressure monitoring in children with diabetes mellitus type-1 (DMT1)

Pulse pressure (PP) and ambulatory arterial stiffness index (AASI) can be calculated from ambulatory blood pressure (BP) monitoring (ABPM) and have been suggested as markers of arterial stiffness and predictors of cardiovascular mortality. We retrospectively evaluated PP and AASI from ABPM records in 84 children (43 boys) with diabetes mellitus type-1 (DMT1) compared with 27 non-diabetic normotensive children. Based on office BP and ABPM, patients with DMT1 were divided into three groups: 24/84 (29%) had hypertension (DM HTN), 33/84 (39%) were normotensive (DM NT) and 27/84 (32%) had white-coat hypertension (DM WCH). DM WCH and DM HTN patients had significantly higher PP when compared with DM NT and NT patients alone (47.62 ± 7.31 and 47.43 ± 8.68 versus 41.45 ± 4.44 and 42.18 ± 5.97, respectively, P=0.0002). Similarly, AASI was significantly elevated in both DM WCH and DM HTN patients when compared with NT patients (0.35 ± 0.14 and 0.36 ± 0.15 versus 0.23 ± 0.15, respectively, P=0.007). In conclusion, children with DMT1 and hypertension, including WCH, had significantly higher PP and AASI levels when compared with normotensive patients. This suggests that these children may be at an increased risk for developing cardiovascular complications later on in life.     

Evaluation of borderline arterial hypertension in young adults by ambulatory arterial pressure measurements

Casual measurements of blood pressure (BP) with a mercury manometer and ambulatory BP recordings with the Spacelabs apparatus at the rate of one measurement every 15 minutes during 24 hours were carried out in two groups of young male adults of the same age. One group consisted of 105 normotensive controls (age 21.2 +/- 1.5 years, weight 69 +/- 8 kg, height 177 +/- 8 cm, casual BP 129/75 mmHg). The other group comprised 104 subjects with borderline hypertension (BHT) as defined by the WHO criteria (age 21.2 +/- 1.6 years, weight 74 +/- 12 kg, height 177 +/- 7 cm, casual BP 148/83 mmHg). Mean levels of recorded BP in controls were: 24 hours 122/70 mmHg, active periods (9 a.m. to 8.30 p.m.) 128/74 mmHg, night 111/64 mmHg. The corresponding values in BHT subjects were: 24 hours 132/83 mmHg, active periods 137/79 mmHg, night 118/67 mmHg. There was no difference between mean casual BP measurements and mean BP recordings during periods of activity in controls, whereas BP recordings during periods of activity were lower in BHT subjects. Results of the two measurement methods showed important individual variations. BP variability (variation coefficient = VC) in BHT subjects was more pronounced in respect of systolic arterial pressure than in controls: Syst VC 24 h: Contr. 12 p. 100, BHT 13 p. 100, p less than 0.001; Diast VC 24 h: Contr. 17 p. 100, BHT 18 p. 100, p less than 0.05. In both populations there was no difference in VC between night and day.(ABSTRACT TRUNCATED AT 250 WORDS)