Biomedical subjects

J P Siche

Publications and source records attributed to J P Siche.

13 recordsLinked to original sources

PubMed1999

Cardiac and vascular remodelling: effect of antihypertensive agents.

The 1996 World Health Organization (WHO) recommendations for mild hypertension stressed the need to evaluate target-organ lesions as treatment criteria. The effects of both vascular and heart remodelling on hypertension must to be taken into account, as they adversely influence the prognosis of patients with hypertension. It was previously demonstrated that at least three classes of antihypertensive agents were able to decrease morbidity and mortality in patients with hypertension. Meta-analyses have shown that angiotensin-converting enzyme inhibitors seem to have a marked effect on regression of left ventricular hypertrophy (LVH). However, the relationship between drug-induced LVH regression and reduced morbidity and mortality remains to be confirmed. The effect of antihypertensive agents on vascular hypertrophy, as assessed by intima-media thickness, and their involvement in reducing morbid events, also have to be determined at the vascular level. As experimental data have highlighted the involvement of angiotensin II in animal models of LVH and vascular hypertrophy development, the role of angiotensin II AT1 receptor blockers should also be assessed in this indication.

Angiotensin Receptor Antagonists↗

PubMed1998

Compliance, electronic monitoring and antihypertensive drugs.

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.

Antihypertensive Agents↗

PubMed1997

Arterial mechanics predict cardiovascular risk in hypertension.

Systolic and diastolic blood pressures are the exclusive mechanical factors considered as predictors of cardiovascular risk for members of populations of normotensive and hypertensive subjects. However, if hypertension is considered as a mechanical factor acting on the arterial wall with deleterious consequences, the totality of the blood pressure curve should be considered in order to investigate the risk. The purpose of this review is to show that in addition to systolic and diastolic blood pressures, other hemodynamic indexes with particular relevance for cardiac complications and that originate from pulsatile pressure should be taken into account, namely brachial pulse pressure, pulse pressure amplification, early wave reflections, and pulse wave velocity.

Adult↗

PubMed1995

[Paradoxic changes in the morphology of blood pressure wave in hypertensive heart diseases].

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.

Adult↗

PubMed1995

Non-invasive ambulatory blood pressure variability and cardiac baroreflex sensitivity.

AIM: The objective of this study was to evaluate the relationship between non-invasive ambulatory blood pressure variability and cardiac baroreflex sensitivity in hypertensive patients. SUBJECTS AND METHODS: Ambulatory blood pressure measurements (15-min intervals for 24 h) and continuous blood pressure measurements (Finapres, 20 min at rest after a 10-min resting period) were performed in 123 untreated hypertensives (resting diastolic blood pressure > or = 90 mmHg; 80 males, 43 females; mean +/- SD age 49 +/- 12 years, range 19-73). Fourier series were used to model 24-h blood pressure profiles (four harmonics). Ambulatory blood pressure variability was assessed by determination of the residuals in each 24-h blood pressure profile (measured minus predicted pressures). Resting blood pressure variability was defined as the SD of the mean Finapres value. Baroreflex sensitivity was evaluated by automatic detection of blood pressure and pulse interval sequences of > or = 3 beats when systolic blood pressure and pulse interval sequences changed in the same direction (increase or decrease: 1 mmHg for systolic blood pressure and 4 ms for RR interval), and was assessed as the slope of the regression line for each sequence. RESULTS: Ambulatory systolic blood pressure variability increased with age (r = 0.28*) and systolic pressure (r = 0.44**). Baroreflex sensitivity (increasing systolic pressure/pulse interval) decreased significantly with age (r = -0.48**) and systolic pressure (r = -0.23**), and was significantly related to increased ambulatory blood pressure variability (r = -0.33**). In a multivariate stepwise analysis the relationship between ambulatory blood pressure variability and baroreflex sensitivity (increasing systolic pressure/pulse interval) was statistically independent of age and systolic pressure (R = 0.55, P<0.001); this relationship was not observed with the corresponding decreasing sequence. CONCLUSIONS: This study shows that in uncomplicated hypertension, ambulatory blood pressure variability is related to baroreflex sensitivity independently of the blood pressure level. This finding has prognostic implications for this non-invasive measurement, which needs to be confirmed by large longitudinal studies.

Adult↗

PubMed1994

Circadian changes of left ventricular ejection fraction in normal subjects.

Sleep has a specific physiology with related cardiovascular changes. We have previously found in respiratory patients [chronic obstructive pulmonary disease (COPD) and sleep apnea syndrome (OSAS)] an unexpected decrease in left ventricular ejection fraction (LVEF) at waking in the morning when compared with the rest period during the day. Whether this observation was linked to the consequences of the respiratory abnormalities or reflected physiological fluctuations related to the changes in autonomic nervous system tone remained unknown. Thus, we have set out to analyze the changes in LVEF with sleep in normal individuals. Eight healthy young men had LVEF measured before and after submaximal exercise, at rest before bedtime, and on waking in the morning. Technetium-99m with in vivo red cell labelling was used. Sleep parameters were assessed using classical polysomnography. In order to detect any influence of autonomic nervous system stimulation on LVEF, sympathovagal tone (SVT) was also assessed during night-time LVEF measurements using spectral analysis of RR intervals. LVEF at rest was within the normal limits for all the subjects (range 51-62%). On submaximal exercise, the LVEF increased in four subjects, was unchanged in two, and decreased in two. The main result concerns the changes in LVEF overnight. In the morning, LVEF decreased dramatically in three subjects and reached a level of < 30% in four. These decreases in LVEF were not related to changes in SVT or sleep structure. LVEF values returned to normal in 30 min. The LVEF changes during exercise are in accordance with previous data in the literature. The dramatic decrease in LVEF observed in the morning could be related either to vascular resistance changes or to nocturnal variations in cardiac contractility, which both need further studies to be established.

Adult↗

PubMed1994

[Ambulatory measurement of blood pressure and efficacy of diltiazem. Influence of the timing of drug ingestion and initial blood pressure level].

Clinical and 24-hour ambulatory measurements were made in 46 patients with mild to moderate essential hypertension in order to confirm that the efficacy and safety of sustained-release diltiazem LP 300 mg were the same regardless of the time of day at which it was taken. After two weeks of placebo, patients were randomly assigned double-blind to take diltiazem LP 300 mg either morning or evening for four weeks. Diltiazem LP 300 mg significantly lowered diastolic and systolic blood pressure in both groups by clinical or 24-hour ambulatory measurement, and without any difference according to whether diltiazem LP 300 mg was administered morning or evening. A lesser fall in blood pressure during the night in both groups led to study of the effect of diltiazem LP 300 mg according to initial ambulatory diastolic blood pressure level. Diltiazem brought about a greater fall in blood pressure when patients had an ambulatory diastolic pressure of 90 mmHg or more. Clinical, laboratory and electrocardiographic parameters were all satisfactory, regardless of the time at which the drug was taken.

Adult↗

PubMed1992

Early disturbances of ambulatory blood pressure load in normotensive type I diabetic patients with microalbuminuria.

OBJECTIVE: To compare 24-h ABP in normotensive type 1 diabetic patients with and without microalbuminuria. RESEARCH DESIGN AND METHODS: The study was a retrospective comparison of cases and matched control subjects. The first phase included 35 type 1 diabetic patients, normotensive by OMS criteria. The 23 patients with normoalbuminuria (< 15 micrograms/min) were compared with 12 patients with microalbuminuria (> or = 15 micrograms/min). In the second phase, the 12 microalbuminuric patients were paired by sex- and age-matched with 12 normoalbuminuric patients and 12 nondiabetic healthy control subjects. We measured casual systolic and diastolic BP and HR, 24-h ABP and AHR (recorded with a Spacelabs automatic recorder), and microalbuminuria. RESULTS: No correlation between microalbuminuria and casual BP was observed. Microalbuminuria was correlated significantly with diastolic 24-h APR and nocturnal systolic and diastolic ABP (r = 0.35, 0.38, and 0.33, respectively; P < 0.05) and with AHR during all time periods (24-h, r = 0.46; day, r = 0.39; night, r = 0.39; P < 0.05). Normo- and microalbuminuric patients did not differ in casual BP and HR. However, microalbuminuric patients had a significant increase in systolic 24-h ABP (119.1 +/- 8.2 vs. 113.1 +/- 8.1, P = 0.05), diastolic 24-h ABP (74.9 +/- 7.5 vs. 70.2 +/- 5.7, P = 0.04), nocturnal systolic ABP (112.8 +/- 7.1 vs. 105.8 +/- 7.9, P = 0.01), and AHR during all time periods. The same results were observed when patients were paired by age and sex. CONCLUSIONS: Normotensive microalbuminuric type 1 patients, although strictly comparable with normoalbuminuric patients for casual BP and HR, have an increased ABP and HR, especially during the night. This difference might reflect dysautonomia. Ambulatory measurement of BP and HR is more appropriate than casual measurements in hemodynamic studies of incipient diabetic nephropathies and could be proposed as an interesting tool for an early prediction of diabetic nephropathy.

Adult↗

PubMed1989

Twenty-four-hour ambulatory blood pressure in shift workers.

Blood pressure and heart rate of 15 male shift workers were measured every 15 minutes for 24 hours during three work shifts: morning, 4:00 AM to noon; afternoon, noon to 8:00 PM; and night, 8:00 PM to 4:00 AM. For each shift, 24-hour systolic and diastolic blood pressure showed a large "trough" (the low pressure span) and a continuous range of elevated pressure (the high pressure span). Fourier series were used to model the 24-hour blood pressure profiles. A careful examination of the residuals (measured minus predicted pressures) showed that four harmonics were necessary to describe the data accurately. The model enabled localization in each blood pressure profile of the high and low pressure spans that did not coincide with the subject's work and rest periods. The time and slope of blood pressure entering and leaving these spans could also be individually determined. Mean blood pressure during the high pressure span was the same for the three shifts, but mean blood pressure during the low pressure span was lower when the subject worked in the afternoon. During that shift, the systolic blood pressure slopes entering and leaving the low pressure span were steeper than during the two other shifts. The high pressure span was longest during the night shift and shortest during the afternoon shift. Therefore, a change in the working time profoundly perturbed the 24-hour blood pressure profile.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1987

[Arterial pressure and shift work activities].

Circadian blood pressure (BP) and heart rate (HR) variations are studied during activities and sleep in a group of nine subjects with shiftwork activities (3 X 8 hours with a short rotation of 2 days). BP and HR values are measured in ambulatory (outside the hospital) with and automatic device (Spacelab system 5,200) during 24 hours at 3 times according to the work periods (morning 7-12 AM, afternoon 3-11 PM, night 1-7 AM) on a month. According to BP hour variations, activities and sleep are the main determining factors. For work periods BP mean values are significantly lower during night than during day. The lower BP values are found during the sleep periods, but the values are higher when subjects sleep during the day. There is an adaptation according to work hour changes, but this adaptation is incomplete and during night activities, the circadian rythm is partly altered. These constatations must be taken in account particularly on a therapeutic point of view for hypertensive subjects for which the treatment must be adjusted.

Adaptation, Physiological↗

PubMed1986

Comparative study of the efficacy of captopril at a single daily dose of 100 mg and at a twice daily dose of 50 mg by measuring ambulatory pressure over 24 hours.

Variations in blood pressure were investigated by an automatic, non-invasive ambulatory method in 9 subjects with essential hypertension. Recordings were made after 6 week periods during which captopril was taken either once or twice daily, in a double-blind cross-over study. Although the effects of captopril administration either once or twice daily were broadly similar, there was a significant decrease in diastolic blood pressure values on the once-daily regimen. These results suggests that treatment once a day can advantageously replace twice-daily treatment.

Adult↗

PubMed1985

[Personality characteristics of hypertensive patients. Study of subjects with essential hypertension compared to a control population].

Starting from projective situations--thematic apperception test (TAT) we have researched personality characteristics liable to be found in hypertensive subjects. With reference to a control group of 59 subjects we have studied 41 essential hypertensive subjects. They undergo a preliminary interview structured on the questionnaire type, are classically tested with the TAT, have one or several free interviews. These data are exploited on three levels and contents = manifest, latent, adaptive. It emerges that there are permanent biographical elements (elements of reactivation. Difficulty to put up with aggressiveness, object loss anxiety, use of operative thought back of adaptation = absence of solution to conflicts and possibilities of passage ?), personality patterns in between obsessional pole neurosis and limit state (Bergeret's nosography). These data partly overlap other research, they encompass a wider field than hypertension, given the structures involved (limit state, psychosomatic component). The lack of mentalization justifies the use of therapeutic techniques such as relaxation, biofeedback...

Adult↗

PubMedDate not supplied

[Comparison of blood pressure profile during exercise with benazepril 10 mg and benazepril 5 mg/hydrochlorothiazide 6.25 mg fixed combination].

This double-blind placebo-controlled study was designed to compare the efficacy of benazepril 10 mg (BZ 10) and the low-dose combination benazepril 5 mg/hydrochlorothiazide 6.25 mg (BZ + HCTZ) on exercise blood pressure in 71 patients with mild to moderate hypertension (diastolic blood pressure 95 to 114 mmHg at the end of a 2 week placebo run-in). A significant fall of systolic (SBF) and diastolic (DBP) blood pressure at rest was seen after a 4-week treatment period in the two active groups (-21.9/-10.3 mmHg with BZ 10, -19.5/-11.2 mmHg with BZ + HCTZ) and was greater in these two groups than in the placebo group (-7.5/-2.5 mmHg, p < 0.01). For each level of the exercise test on bicycle ergometer, SBP falls seen after 1 month were significant in the two active groups (from -15 to -23 mmHg depending on the level and treatment group). The evolution of the SBP/heart rate slope was significantly different among the two active groups in favour of the BZ 10 regimen. The exercise test proved to be a valuable tool to show any difference between two treatments with comparable efficacy on SBP/DBP at rest.

Adolescent↗