Prescribing practices in the management of hypertension in the Caribbean's.
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This year, the writing of "Best of hypertension 2002" was completed by the coordinators of 4 working groups of the French Society of Hypertension, in various domains: (a) the working group on BAroreflex and VARiability (BAVAR): it appeared mandatory to evaluate the influence of calculation methods on the values of spontaneous baroreflex sensitivity, through an european study (The EuroBaVar collaboration study); (b) the working group on Blood Pressure Measurement, was first involved in the establishment of an international protocol for the validation of self blood pressure measurement, then validated, according to this procedure and in collaboration with the French Medicine Agency, several apparatus dedicated to the French market; (c) the working group on epidemiology: after the publication of the IHPAF study (Incidence de l'hypertension dans la population active française), which unmasked the influence of social and professional determinants on blood pressure control, this group settled down ancillary studies in French Indias, the INAPAG study (INcidence de l'hypertension artérielle dans la population Antilles-Guyane), and the PHAPPG study (Prévalence de l'hypertension artérielle dans la population précaire guadeloupéenne); finally (d) the working group for continuous medical education settled down a national diploma, entitled "Hypertension and renal and cardiovascular risk".
In addition to conventional risk factors, environmental and occupational strain is an actor of the development and evolution of cardiovascular diseases. In industrialised countries, cardiovascular mortality is inversely correlated with the socio-economic level and type of occupation. In the French Ihpaf study, systemic hypertension and obesity were correlated with the socio-economic level. Among possible explanations for the importance of occupational environment, psychological stress at work, sedentary jobs, passive smoking and shift working may all play a role. Thus, beyond the conventional approach to individual risk factor management, it appears necessary to consider cardiovascular prevention through collective actions taking into account occupational environment.
To investigate the effect of amlodipine on baroreflex sensitivity and sympathetic system activity, 36 patients with essential hypertension were randomized to once-daily, double-blind treatment with amlodipine 5 mg or placebo 5 mg for 60 days. Measurements with a Finapres device allowed calculation of baroreflex sensitivity and blood pressure (BP) variability. Adrenergic activity was assessed via measurements of lymphocyte beta2-adrenoceptors and plasma catecholamine concentrations. Compared with placebo, amlodipine significantly decreased BP, but did not significantly alter baroreflex sensitivity. Spectral analysis of Finapres data showed that, compared with placebo, amlodipine decreased the variability of systolic blood pressure, diastolic blood pressure, and RR interval in the low frequency band. There were no simultaneous changes in adrenergic function, however, suggesting that these effects of amlodipine were not mediated via sympathetic nervous system activation.
-To assess blood pressure (BP) control in a French working population through the use of a careful assessment of BP based on 2 different visits in 1 month, 17 359 men and 12 267 women were evaluated from January 1997 to April 1998. The initial phase was a cross-sectional analysis of a cohort study designed to assess the incidence of arterial hypertension in a French working population. Information was collected by the work-site physician during the annual examination. BP was measured with a validated automatic device. Among subjects with BP >/= mm Hg, patients not treated with antihypertensive drugs were invited to have an additional BP measurement taken 1 month later. The prevalence of hypertension (BP >/= mm Hg) based on 2 visits was 16.2% in men and 9.4% in women. When the diagnosis of hypertension was based on 2 visits, its prevalence was 41% lower in men and 36% lower in women compared with that of a diagnosis based on a single visit. Accordingly, the awareness of hypertension was 49% higher in men and 40% higher in women. Overall, 12.5% of hypertensive men and 33.2% of hypertensive women taking antihypertensive medication had their BP levels lowered to < mm Hg by treatment. Although the percentage of hypertensive men and women under current treatment who were aware of their hypertension increased with age, BP control among treated subjects decreased with age. Ineffective BP control with treatment accounted for 33% of BP levels >/= mm Hg in men and 40% of those observed in women. In this large French working population, estimates of hypertension therapeutic control depend heavily on the number of BP measurements. Despite these methodological precautions, insufficient awareness of BP and insufficient BP control through treatment remain 2 major public health problems.
Validation of automatic devices for self blood pressure measurement is a necessity, as the mercury columns are no longer available. The European consensus meeting organized by the Group for blood pressure measurement and evaluation (GEM), from French Society of Hypertension held last June 1999 has defined a new international protocol for clinical validation of these devices. The main parts of this protocol are the following: the blood pressure is measured at the same arm with two observers simultaneously and then with the automatic device sequentially seven times among 38 patients. The evaluation is interrupted after the 15th patient if the pre-analysis fails defined criteria. Technical supports are available: A CD-rom from French society of HTA for the training and certification of observers, a special kit for the evaluation (2 mercury column's and a double stethoscope) and a specific software for data analysis created by the GEM.
OBJECTIVES: To pool data from individual subjects in an attempt to determine an operational threshold for making clinical decisions based on the self-recorded blood pressure (SRBP) and to examine how many hypertensive subjects, diagnosed by conventional blood pressure (CBP) measurement, would have a self-recorded blood pressure within the normotensive range if the proposed thresholds were applied. DATA SOURCES: Thirteen research groups studied 4668 untreated subjects. RESULTS: In total 2401 subjects were normotensive, 494 were borderline hypertensive and 1773 were definitely hypertensive. Hypertension had been diagnosed from the mean of 1-6 (median 3) CBP measurements obtained during 1-3 (median 1) visits. The reference values for SRBP measurements determined from the 95th percentiles of the distributions for normotensive subjects were 137 mmHg systolic and 85 mmHg diastolic. Of the subjects with systolic hypertension, 16% had systolic SRBP </= 137 mmHg. Similarly, 25% of those with diastolic hypertension had diastolic SRBP </= 85 mmHg. The probability that hypertensive subjects had SRBP below these thresholds was 34% (diastolic) to 62% (systolic) greater for women than it was for men, was 2-3 times greater if fewer than three CBP measurements had been averaged for establishing the diagnosis of hypertension, and increased by 50% (diastolic) to 126% (systolic) when SRBP had been measured on more than 3 days. In contrast, for each 10 mmHg increment in systolic CBP, this probability decreased by 35% for systolic SRBP and by 11% for diastolic SRBP; for each 5 mmHg increment in diastolic CBP it decreased by 36% for diastolic SRBP. In addition, for systolic blood pressure, the probability decreased by 31% for each 10-year increment in age. CONCLUSIONS: Until the relationship between SRBP and the incidence of cardiovascular morbidity and mortality has been clarified further by prospective studies, a mean self-recorded blood pressure above 137 mmHg systolic or 85 mmHg diastolic may be considered hypertensive. Among the hypertensive patients 16-31% had SRBP below these thresholds, but this proportion decreased if the hypertensive subjects had higher CBP.
UNLABELLED: This work tests a new ambulatory blood pressure device: Save 33 II. The evaluation is conducted according to the phases II and IV of the British Hypertension Society (BHS) protocol: the phases I and III (before and after use) are not performed as this device has received the European quality label 'CE' that guarantees a +/- 3 mmHg accuracy before and after 10,000 simulated cycles. Two trained observers (hearing test and certification done according to the BHS recommendations) have performed 7 sequential BP measurements with conventional and automatic method, at the same arm, among 85 patients. The ranges of mean blood pressure are 78-203 mmHg, for SBP and 53-130 mmHg for DBP. RESULTS: The Save 33 II monitor satisfies the grade B of BHS evaluation for both systolic and diastolic pressures. This device also satisfies the Association for the Advancement of Medical Instrumentation (AAMI) protocol: mean difference between methods and standard deviation less than 5 +/- 8 mmHg: -2.7 +/- 6.8 mmHg for SBP and -0.86 +/- 6.6 mmHg for DBP. The in-use assessment is conform to BHS criteria for 20 recordings (less than 20% invalid values during day and night); the 5 other recordings have not enough night values, due to batteries failure (2 cases), sleeping discomfort (2 cases) and a cuff withdraw. CONCLUSION: This device, in the tested configuration, agrees the B grade of BHS and can be recommended for ambulatory blood pressure measurement.
BACKGROUND: The widespread clinical use of self-recorded blood pressure measurement is limited by the lack of generally accepted reference values. The purpose of this study was therefore to perform a meta-analysis of summary data in an attempt to determine an operational threshold for self-recorded blood pressures. STUDIES AND METHODS: Seventeen studies, including a total of 5422 subjects, were reviewed. Eight of these 17 studies included both normotensive and untreated hypertensive subjects, while the other 9 reports included normotensive subjects only. Within each study an operational cutoff point between normotension and hypertension was derived by means of the mean+2 SDs and the 95th percentiles of the self-recorded blood pressure in normotensive subjects. These 2 methods were contrasted with 2 other techniques that have been applied in the literature to calculate (1) the self-recorded pressures equivalent to a conventional pressure of 140 mm Hg systolic and 90 mm Hg diastolic by means of regression analysis and (2) the self-recorded blood pressures at the percentiles corresponding to a conventional pressure of 140/90 mm Hg. The latter 2 methods were applied in untreated subjects not selected on the basis of their blood pressure. RESULTS: With weighting for the number of subjects included in the various studies, the self-recorded blood pressure averaged 115/71 mm Hg in normotensive persons and 119/74 mm Hg in untreated subjects not selected on the basis of their blood pressure. The reference values for self-recorded blood pressures determined by the mean+2 SDs (137/89 mm Hg) or the 95th percentile (135/86 mm Hg) of the distribution in normotensive subjects were concordant within 2/3 mm Hg, whereas the cutoff points derived with the regression and percentile methods were considerably lower, ie, 125/79 and 129/84 mm Hg, respectively. CONCLUSIONS: Until the relationship between self-recorded pressure and the incidence of cardiovascular morbidity and mortality is further clarified by prospective studies, a mean self-recorded blood pressure above 135 mm Hg systolic or 85 mm Hg diastolic may be considered hypertensive.
Hypertension, even of mild-to-moderate severity, is undoubtedly a risk factor for cardiovascular morbidity and mortality. It has been well demonstrated, in numerous studies that have been subjected to meta-analysis, that the introduction of antihypertensive treatment leads to reductions in cardiovascular and cerebrovascular events. These results can be obtained with even a moderate reduction in blood pressure, of the order of 4-5 mmHg in diastolic blood pressure. However, many studies have shown that the percentage of treated hypertensive individuals who have a reduction in blood pressure to normal values of systolic blood pressure/ diastolic blood pressure (< 140/90 mmHg) is of the order of 30%. The reduction in blood pressure data are well correlated with the level of compliance. This compliance can be defined as the adherence by the patient to the directions given by the doctor for medication dosage, and this can be considered as 'good' when it is of the order of 80%. Until recently the examination of compliance relied on questioning the patient, pill counts or ultimately blood sampling for drug levels, which could be used only in research. The use of an electronic pill box with a microprocessor in the cover that records the date and hour each time the box is opened is a precise method of recording compliance. The purpose of such a method is to study overall compliance, which deteriorates as time passes and falls by approximately 50% after 1 year. However, this compliance can be modified and improved if instruction and follow-up are given to the patient. Prescription compliance can be improved by once daily dosing and by instructing for this to be taken in the morning. In contrast compliance is considerably reduced when more than two doses are to be taken each day. Using the pill counting box allows us to describe and focus on different types of patients, ranging from rigidly adherent to completely chaotic. It seems that factors such as age and activity can influence these patterns of compliance.
While measurement of blood pressure in the doctor's office remains the method of reference of the WHO, self-measurement yields complementary information, namely: measures outside the surgery, good estimation of the level of blood pressure at home from several day's data, better reproducibility related to standardized conditions of measurement imposed by the constraints of immobility and manoeuvre of the machine. The modalities of variation of BP by automeasure are known: diminution in the BP by automeasure of about 2 to 4 mm Hg between the first and the third measure performed at 1-min intervals, no significant evolution over 3 days and BP more elevated in the evening than in the morning. In comparison with the WHO data, the BP is significantly lower. Recently reference values have been proposed, giving as the upper threshold of normotension = 127/ 83 mm Hg and hypertension = 147/ 86 mm Hg. As regards diagnosis SM allows the identification of "white coat hypertension", and thus avoids treating these patients. The indirect prognostic value via target organ effect is under evaluation, and may be at the same level as ambulatory blood pressure measurement (ABPM). Given the utilisation of validated automatic machines and a rigorous methodology SM is beginning to be used satisfactorily in clinical trials. Numerous studies are still necessary in order to clearly define the place of SM in comparison to WHO and AMBP in the management of hypertension.
INTRODUCTION: We hypothesize that in essential hypertension sympathetic nervous activity is related to the development of left ventricular hypertrophy, which can be regarded as a measure of the severity of hypertension. METHODS: Using spectral analysis, we studied the short-term variability in resting blood pressure and heart rate in essential hypertensive subjects. We measured blood over 10 min using a Finapres in 88 subjects after 20 min rest. We performed echocardiography to evaluate left ventricular hypertrophy and thereby identified three groups: 23 control subjects (group I), 29 hypertensive subjects (World Health Organization criteria) without left ventricular hypertrophy (group II) and 36 hypertensive subjects with left ventricular hypertrophy (group III). None had been treated for hypertension before the study. RESULTS: The variability in blood pressure over a low-frequency period considered to be a marker of sympathetic activity was significantly increased in group II compared with groups I and III (analysis of covariance taking into account blood pressure and age). The variability in heart rate was similar in groups II and III, but both groups had a significantly reduced variability in heart rate compared with group I. CONCLUSION: These data, which examine globally, using a non-invasive method, all neurohormonal factors associated with the development of left ventricular hypertrophy, demonstrate that, in the time course of hypertension, low-frequency oscillations in blood pressure and heart rate are shifted to a lower level, presumably reflecting altered function of the sympathetic nervous system. We suggest that spectral analysis of blood pressure at rest in hypertensive patients can lead to complementary information to single measures of blood pressure and detect differences in the cardiovascular regulatory system.
UNLABELLED: The objective is to study the relation between left ventricular (LV) effect (index of LV mass (LVMI) and index of inotropic state) and arterial compliance determined but the proximal aortic pressure waveform and by the carotid femoral pulse wave velocity. MATERIAL: 72 untreated hypertensives; systolic blood pressure (SBP) 170 +/- 18 mmHg/diastolic blood pressure (DBP); heart rate: 69 +/- 9 batt/min; age: 48 +/- 13 years; duration of hypertension 4.6 +/- 4.8 years; sex ratio 49 M/23 F. OBJECTIVE: Proximal aortic pressure waveform (carotid artery) was studied by applanation tonometry. We derived the index of amplification (AI = Pmax-Pinflex)/PP, %), pulse pressure (PP), the maximum rate of rise of pressure (dpdt, mmHg.s-1). Echocardiography was used to define the index of LV mass (VLMI), end systolic volume (ESV), end systolic stress (ESS), myocardial contractile force (ESS/ESV), inotropic state (SBP/ESV). Carotid-femoral pulse wave velocity was determined by mechanogram (PWW m/s). RESULTS: 1. Relationship of physiological changes of AI and SDA to age, height, PP, DBP, PWV, and LVMI were observed in table I (r-Pearson cor. coefficient, * < p 0.05; **: p < 0.001). [table: see text] In stepwise regression analysis, even allowing for BP, age, and height, there was no relationship between LVMI and the index of aortic amplification (AI). 2. In the subjects with LVH (LVMI > 110 g/m2) we found a bimodal distribution of the AI which defines two groups in agreement with the Murgo Classification. [table: see text] In type B, where AI is weaker, the indices of aortic rigidity are reduced, there is an increased ESS and a paradoxal fall in LV performances. CONCLUSION: Analysis of proximal aortic pressure waveform don't allow to predict index of LV mass. These results suggest that in the sphere of LV aortic compiling the reduction of LV function contributes to modification of the BP waveform with diminution of dpdt and the index of amplification.
Ambulatory blood pressure monitoring (ABPM) is now widely used for the assessment of antihypertensive drugs. This procedure may be used in phase II studies in dose-ranging evaluations as well as in phase III in order to assess the drug efficacy in the patient's natural environment. The increase in the reproducibility related to the repetition of blood pressure measurements by ambulatory monitoring may improve the accuracy of the trial and minimize the numbers of subjects required. Placebo fails to lower ambulatory blood pressure in almost all studies. Nevertheless, placebo is always necessary in clinical studies with ABPM at least for the pre-inclusion phase and in order to study the peak-trough ratio. This ratio may be accurately assessed by ABPM. Finally, ABPM may be useful to rule out "white coat" responders, who are not really hypertensive patients.
UNLABELLED: Relationships between baroreflex sensitivity (BRS) and arterial distensibility are evaluated by continuous measurement of blood pressure (Finapres) and carotid-femoral pulse wave velocity measurement (PWV); 73 subjects are recruited on WHO criteria (age: 48 +/- 13). An ambulatory measurement of BP is also performed to evaluate the mean BP 24 level. The BRS is evaluated at rest during 20 min of acquisition data in a lying position, using a dedicated software [(automatic detection by of BP sequences were 3 or more systolic BP and RR interval increased of 1 mmHg for SBP and 4 ms for RR (PS+/RR+) or decreased (PS-/RR-)]. The BRS is the slope of the regression line between SBP and RR interval of each sequences (if correlation coefficient > 0.95). RESULTS: resting BP: SBP/DBP = 170 +/- 12 mmHg. HR 72 +/- 15 batt/min, PWV = 10.8 +/- 3.2 m/s. Mean BRS is 8.2 +/- 3.8 for PS+/RR+ and 8.7 +/- 3.8 ms/mmHg PS-/RR-. The coefficient of correlation (Pearson) between PWV and BRS is -0.59* for PS+/RR+ and -0.41* for PS-/RR- (*: p < 0.01). In multivariate analyses, these relations were statistically independent of age and BP for the sequences PS+/RR+ but not for the sequences PS-/RR- suggesting a predominant vagal alteration in hypertensive subjects associated with the alteration of carotido-femoral pulse wave velocity.
Ambulatory blood pressure monitoring (ABPM) is a particularly useful method for evaluating the effects of antihypertensive drugs. ABPM allows the therapeutic effect of an agent to be assessed continually by a large number of measurements, and the greater number of readings contributes to the higher degree of reproducibility associated with ABPM compared to other methods for measuring blood pressure. ABPM also enable measurements to be taken in "real-life" situations and removes the problem of observer bias. The number of patients required for clinical studies can be significantly reduced by using ABPM. It is still essential, however, to identify "white coat" subjects, placebo responders, and patients who do not respond to the treatment. ABPM studies have demonstrated that the novel dihydropyridine calcium antagonist, lacidipine, significantly reduces both systolic and diastolic blood pressures over a 24-h period, both during the day and at night. Furthermore, although the trough-to-peak ratios of many calcium antagonists have been shown to fall below the recommended level of 50%, lacidipine has a ratio above 60%. Other ABPM studies have also shown that lacidipine can correct the 'early morning increase' in blood pressure without effecting the 24-h nycthemeral profile.
To study the relationship between assessment of blood pressure (BP) variability measured by continuous measurement (Finapres) or discontinuous ambulatory (ABPM Spacelabs) in 70 untreated essential hypertensive subjects (mean age 51 +/- 12) and their relationship with the development of left ventricular hypertrophy (LVH). There is no relationship between the BP variability measurements either by Finapres nor by ABPM. Multiple regression analysis show that ambulatory systolic BP variability (standard deviation) and resting BP variability (spectral analysis of SBP in the medium frequency band 0.1 Hz) are related to LVH index when we take into account age and BP difference (to explain LVH) (p < 0.001) ABPM SBP variability increase with LVH, while resting SBP measurement of BP variability (Mayer waves) significantly decreased. The study points to the different role of BP variability measurements in the mechanisms related to left ventricular hypertrophy and to the interest of continuous BP resting spectral analysis measurements.
OBJECTIVE: To study the relationship between spectral analysis measurement of blood pressure (BP) and heart rate (HR) at rest, in untreated essential hypertension, and their relationship with the development of left ventricular hypertrophy (LVH). DESIGN AND METHODS: 41 untreated hypertensives (25M/16W, age 50 +/- 12, range 23-73) were measured at rest (WHO criteria DBP > 90 mmHg) by digital continuous photoplethysmography (Finapres 2300 (F), 6 mn of measurement in the dorsal decubitus position and standing up). Measurement of LVH (Devereux criteria, left ventricular mass index LVMI, g/m2) to analyse two groups (LVMI+: LVMI > 107 if women and 120 if men; n = 19; LVMI = 137 +/- 25), and (LVMI-; n = 22; LVMI = 92 +/- 17). The overall variability is standard deviation (SD), spectral analysis variability (SA) is FFT of 256 points over 3 periods low (LF: 0.004-0.07Hz), medium (MF: 0.07-0.13Hz), high (HF: 0.13-0.5Hz). Comparisons by Wilcoxon test and Anova (age, sex) (* p < 0.05, ** p < 0.01). RESULTS: By WHO criteria, the SBP was significantly lower in the LVMI-group (153 +/- 10 vs 165 +/- 18**), the DBP was not significantly different (94 +/- 6 vs 96 +/- 10). By continuous measure (F) at rest there was no significant difference for SBP or DBP. On standing up the SBP was significantly lower in the LVMI-group (148 +/- 20 vs 162 +/- 22**). The SD of the DBP at rest was more elevated in the LVMI-group (3.34 vs 3.06*), but not significantly different standing up. There was no significant difference in SBP at rest (6.7 vs 6.32) or standing (9.13 vs 11.5). The Spectral analysis of the MF was significantly elevated in the LVMI-group at rest for SBP (3.56 vs 3.01*), DBP (1.99 vs 1.19*), and HR (1.79 vs 1.77*). This was not significantly different in the LF and HF for SBP, DBP, HR. CONCLUSION: These results are different from those obtained by invasive ambulatory measures. The spontaneous variability in BP and HR at rest is increased when there is no cardiac effect (LVMI-). SA gives additional information in showing that the increase in variability is due to an increase in the Mayer waves, suggesting the existence of an elevation in adrenergic tone in hypertensive patients not having LVH.