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Biomedical subjects

G Chatellier

Publications and source records attributed to G Chatellier.

At least 217 records · Page 12Linked to original sources

Integrating management and expertise in a computerised system for hypertensive patients.

An expert system has been integrated to the data management system of the ARTEMIS programme for hypertensive patients. The patient database, which has been used since 1975, contains the medical records of about 20,000 patients. Information is interactively entered by physicians, nurses and secretaries on video display units. The computerised medical record has replaced the traditional handwritten medical record. The database management system is used to produce different summary reports (inpatient and outpatient care) and personalized recall letters which are mailed to the patients before their appointments. Suggestions provided by the expert system include additional information to be obtained (complementary patient interrogation, biological or radiological investigations, etc.), possible causes of hypertension, and medical prescriptions. The information base allows the description of both static knowledge (in the form of a semantic network) and dynamic knowledge (in the form of production rules). The inference system sequentially uses a combination of forward and backward chaining and performs both exact and approximate reasoning. The diagnostic performance of the expert system was evaluated in 100 cases of hypertension (50 of essential hypertension and 50 of secondary hypertension. Concordance between the diagnosis proposed by the expert system and the one proposed by the specialist was achieved in 92% of secondary hypertension cases and 88% of essential hypertension cases. It is suggested that the integration of data and knowledge management might enhance the overall acceptance by medical staff of a computerised system, and facilitate the validation of a knowledge base.

Database Management Systems↗

Factors predictive of perinatal outcome in pregnancies complicated by hypertension.

Perinatal outcome and various indicators of perinatal risk were analyzed in a prospective study of 268 pregnant women with hypertension. Poor perinatal outcome was defined by stillbirth (n = 13), neonatal death (n = 2), and in surviving babies, by birth before 32 weeks or a birthweight below 1500 g (n = 13). In multivariate analysis, proteinuria and onset of hypertension between the 27th and 36th weeks of amenorrhea were the only two independent indicators of poor outcome (relative risks of 4.0 and 3.7, p less than 0.001 and p less than 0.01 respectively). Both these indicators were more frequent in mothers with no history of pre-pregnancy hypertension.

Adult↗

Reversible renal failure after combined treatment with enalapril and frusemide in a patient with congestive heart failure.

A patient with congestive heart failure and moderate renal insufficiency developed severe reversible non-oliguric renal failure while on frusemide and enalapril. Renal failure developed when enalapril was given in the presence of pronounced sodium depletion. When positive sodium balance was restored the plasma creatinine concentration began to fall while angiotensin converting enzyme inhibition remained effective and blood pressure was stable. These observations suggest that the degree of sodium depletion plays an important role in the tendency for angiotensin converting enzyme inhibitors to induce renal failure in patients with congestive heart failure and moderate renal insufficiency. Restoration of a positive sodium balance promotes the recovery of renal function after the combined administration of angiotensin converting enzyme inhibitors and diuretics.

Acute Kidney Injury↗

[Testing an expert system for hypertension].

An Expert System (ES) has been connected to a database management system for the management and follow-up of hypertensive patients. The patient data base, called Artemis, contains approximately 18,000 medical records. About 90% of the initial informations used by the ES is contained in the medical records of the Artemis data base. The knowledge base consists of 870 rules. A first group of rules allows the description of knowledge structures (hierachies, graphs and mutual exclusions). The second group consists of production rules which describe the dynamic reasoning of the expert. The inference engine uses a combination of forward and backward chaining. The ES produce diagnostic hypotheses (possible causes of hypertension) and therapeutic suggestions before and after requiring additional information (patient supplementary interrogation, biological or radiological investigations). The evaluation of the diagnostic performance of the ES was made on 40 confirmed cases of secondary hypertension (SH) and 40 cases of essential hypertension (EH). The initial initial diagnosis, just after the forward chaining step, was correct in 17 cases of SH and 32 cases of EH. The final diagnosis proposed after several steps of forward and backward chaining was correct in 37 cases (92%) of SH and 36 (90%) of EH. Averages of 5 (EH) and 8 (SH) questions were formulated by the ES to reach the final diagnosis. The integration of the ES to the database is expected to facilitate the validation of the knowledge base and to enhance its overall acceptability. Whether or not such an integration will be useful and accepted as a complementary tool by physicians remains however an open question.

Decision Making, Computer-Assisted↗

[Comparison of ambulatory blood pressure determinations using the Remler and Spacelabs devices].

Ambulatory blood pressure recorded with the Spacelabs was compared with both Remler recordings and office blood pressures in 11 normotensive and 13 hypertensive volunteers. Analysis of 324 simultaneous measurements with Remler and Spacelabs showed very high correlation for systolic and for diastolic blood pressure. For systolic blood pressure, measurements with Spacelabs recorder were lower than those with the Remler recorder by a mean of 3.6 +/- 6.5 mmHg, principally in hypertensive subjects. Spacelabs measurements were also lower than Remler measurements for diastolic blood pressure by a mean of 5.3 +/- 6.6 mmHg principally in normotensive subjects. The averages of blood pressure variability (standard deviation as index) recorded by each device were identical. Mean systolic and diastolic blood pressure differed by more than 10 and 5 mmHg respectively between the two devices in 11 and 83% of the subjects. These individual discrepancies were unpredictable. Comparison of Spacelabs records with office blood pressure measured with a standard mercury manometer showed discrepancies of more than 10 mmHg for systolic blood pressure and more than 5 mmHg for diastolic blood pressure in 46 and 42% of the 24 subjects, respectively. These discrepancies could be due, in part, to different methods of blood pressure measurements. These data demonstrate that the Spacelabs apparatus provides records for a group, reasonably close to those obtained with the Remler over a wide range of blood pressure. For the management of hypertension, the advantages--as compared to physician's measurements--of ambulatory blood pressures recorded with indirect methods,need to be weighed, taking into consideration the difference between the ambulatory record and the office blood pressure measured with the same device.

Blood Pressure↗

[Predictability and prevention of hypokalemia induced by hydrochlorothiazide].

In a double blind study, 104 hypertensive patients were randomly allocated to two different stepped care programs for 6 months. Following a placebo run-in-phase, patients were given either Enalapril (EN) 20 mg once-a-day, or a Placebo (PL). Drugs were added as follow in a parallel stepwise sequence, until the goal blood pressure was obtained. First Hydrochlorothiazide (HCTZ) and then, if necessary, Oxprenolol (OXP) and Dihydralazine (DIH). The two goals of this study were to lower diastolic blood pressure below 90 mmHg and to maintain plasma potassium above 3.5 mmol/l. Amiloride was prescribed if plasma potassium was lower than 3.5 mmol/l. At the end of the study the EN group's blood pressure was 130 +/- 12/83 +/- 6 mmHg, the tablet's daily number was 2.6 +/- 1.8 and Amiloride was necessary in 15 patients. These parameters were significantly different from those observed in the Pl group (BP: 136 +/- 9/87 +/- 5 mmHg, tablets 4.2 +/- 2.4; amiloride necessary in 34 patients). The effects of HCTZ were evaluated in 32 patients previously treated by EN compared to 39 patients receiving PL. The converting enzyme inhibition minimized the fall in plasma potassium induced by HCTZ (3.6 t +/- 0.4 vs 3.3 +/- 0.5 mmol/l, p less than 0.05). Related to the HCTZ dose (mg/kg), the plasma potassium fall is lower in the EN group (0.46 +/- 1.1) than in the PL group (0.94 +/- 0.9, p less than 0.05). The plasma potassium reduction could not be predicted by age, plasma renin activity, plasma and urinary aldosterone or urinary kallikrein.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗

Influence of educational and sociocultural factors on hypertension care.

The influence of occupational category (OC) on the prevalence of hypertension (HT) and cardiovascular risk factors and on their management was studied in Paris in a general population and in a series of patients followed up in two university hospital hypertension clinics. Three OCs were defined as follows: high executives and members of liberal professions middle executives and clerks and manual workers. In the general population, the prevalence of HT was positively associated with OC, and ranged from 12.8% (1) to 19.3% (3). Body Mass Index (BMI) and tobacco and alcohol consumption were higher in category 3. Exposure to noise and assembly-line work raised blood pressure. Of the hypertensive subjects, 60% were aware of their illness, independently of OC, but the percentage of treated hypertensive subjects at examination and their compliance with treatment were significantly and negatively correlated with OC. In the hypertension departments, more category 1 and 2 patients were examined than expected for a theoretical French population of similar sex, age and geographical distribution. By contrast, clerks and manual workers were under-represented. BMI was higher in OC 3 than in OC 1, in both sexes. Cigarette consumption was higher in OC 1 than in OC 3 in males only. Permanent teaching staff members examined more people from OC 1 than the other physicians did. Drop-out rates at 1, 2 and 3 years were higher in OC 3 than OC 1. The problems of compliance with antihypertensive treatment were more frequent in OC 3 patients than in those in the other categories.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Variability of arterial pressure during consultation. Effect of the physician and patient characteristics].

The decision to treat patients with high blood pressure depends largely on the level of pressure. However, a major difficulty is the great variability of blood pressure level in any individual patient. From May 1st 84 to July 1st 84, 259 patients were referred for the first time to the outpatient clinic and were seen by one of the four physicians. Before the consultation and during the medical interrogatory 18 + 8 measures were performed every 2 minutes by an automatic device using the oscillometric method. The physician measured the blood pressure (BP) using the auscultatory method according to the WHO recommendations, after the medical interrogatory. Measured by the physician, BP was 174 + 28/104 + 15 mmHg. Measured by the automatic device, BP was 158 + 22/94 + 14 mmHg. The correlation between the two methods was excellent (SBP: r = 0.88 and DBP: r = 0.82; p less than 0.001) but the mean of BPs automatically recorded was significantly lower (-15/11 mmHg) than the BP measured by the physician. The mean of the highest BPs recorded by the oscillometric method (179 + 26/108 + 16) was slightly higher than the BP recorded by the physicians. Blood pressure variability was defined by the standard error (SE) of BPs measured by the automatic device (SE: 11 + 4/7 + 2). SE was positively correlated with the BP level measured by the physician or by the machine and with the heart rate variability for both SBP and DBP, and with patient's age for SBP only. SE was negatively correlated with the coffee consumption and the tobacco consumption. Blood pressure variability was significantly higher in men than in women (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

[Plasma renin and catecholamine activity in pheochromocytoma].

We have studied the renin aldosterone system and plasma catecholamines in 26 untreated patients with phaeochromocytoma, 21 untreated patients with primary hypertension, and in 10 normal volunteers. Blood pressure (mmHg), plasma renin activity (radioimmunoassay of angiotensin I, ng/ml/h), plasma concentrations of aldosterone (direct radioimmuno-assay, pg/ml), adrenaline and noradrenaline (radioenzymatic assay with catechol-O-methyl transferase, pg/ml) were measured after 1 h of supine rest, 5 mn upright and after walking 1 h. Seven patients with phaeochromocytoma were subsequently given 400 mg acebutolol bid for 3 days, and five were given 1 mg/kg captopril. Supine renin activity was higher in phaeochromocytoma than in primary hypertension and in volunteers (average 2.54, 1.03 and 0.85, F = 7.1, p less than .01) and rose higher after walking (mean increase 3.84, 1.19 and 0.68 respectively, F = 6.3, p less than .01). Aldosterone was higher after walking in phaeochromocytoma than in primary hypertension (534 vs 275 pg/ml, p = .03). Differences in renin and aldosterone could not be explained by age, natriuresis or plasma volume. Catecholamines were as expected much higher in phaeochromocytoma than in the other two groups (p less than .01). At variance with primary hypertensive and normal volunteers, renin was tightly correlated with noradrenaline in patients with phaeochromocytoma (r' = .54, r' = .60, and r' = .74 in supine position, after standing and after walking 1 h, p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗

[Alcohol and arterial hypertension].

The positive association between alcohol consumption and arterial pressure has been shown in several epidemiological surveys. This strong relationship has been demonstrated in many countries, independent of the known risk factors for hypertension; the dose-response appears to be linear in most studies. The lowering of blood pressure after stopping alcohol consumption and its rise after starting to take alcohol again are good evidence of a causal relationship. The pathophysiology of the hypertensive effect of alcohol is uncertain. Alcohol consumption seems to be a factor to be taken into account in the prevention and treatment of hypertension.

Alcohol Drinking↗

Antihypertensive effect of enalapril as first-step treatment of mild and moderate uncomplicated essential hypertension. Evaluation by two methods of blood pressure measurement.

The new angiotensin converting enzyme inhibitor enalapril (MK-421), was given in a single daily dose of 20 mg to 53 patients with uncomplicated essential hypertension. Its effects were compared with those of a placebo given to 47 patients on a double-blind randomized basis. The blood pressure was measured in all patients by a physician, using a mercury sphygmomanometer, and by an automatic device in the absence of the physician. After 15 days of treatment, enalapril induced a significant reduction in systolic blood pressure (161.4 +/- 13 versus 145.1 +/- 15, p less than 0.001) and in diastolic blood pressure (103.3 +/- 6 versus 92.9 +/- 8, p less than 0.001) measured by the physician. The magnitude of the fall in blood pressure was identical after 30 days of active treatment. The reduction in blood pressure induced by enalapril was similarly detected by both methods of measurement, despite the fact that blood pressure values were higher when measured by the physician. A placebo effect was observed with the physician's values that was not present with the automatically recorded values. A very significant correlation between blood pressure values obtained by these two methods was observed. However, among nine of 53 patients treated with enalapril, a difference in the decrease of blood pressure of 10 mm Hg or more was noted between the two methods of measurement. The decrease in blood pressure occurred with no change noted in the pulse rate or orthostatic hypotension. Plasma renin activity increased after treatment. No changes were observed in creatinine clearance and plasma electrolyte levels.

Adult↗

A double-blind randomized evaluation of converting enzyme inhibition as the first-step treatment of mild to moderate hypertension.

The new angiotensin converting enzyme inhibitor, enalapril (MK-421), was tested by a double-blind trial. Patients with uncomplicated essential hypertension were randomly allocated to one of two stepped-care treatment groups: enalapril 20 mg once-a-day, or placebo as the first step, followed when necessary by the successive addition of hydrochlorothiazide (25 and 50 mg), oxprenolol (160 and 320 mg) and dihydralazine (50 and 100 mg). Blood pressure was normalized in both groups, although the enalapril group showed lower systolic and diastolic blood pressures than the placebo group (systolic 130.5 +/- 12 versus 136.6 +/- 9 mmHg, P less than 0.01; diastolic 82.8 +/- 6 versus 87.0 +/- 5 mmHg, P less than 0.001). These results were obtained with a smaller number of tablets per day (2.6 +/- 1.8 versus 4.2 +/- 2.4 mmHg, P less than 0.0001). Plasma potassium was identical for both groups at the start of treatment. At the end of the study, it was significantly higher in the enalapril group than in the placebo group (4.1 +/- 0.3 versus 3.9 +/- 0.5 mmol/l; P less than 0.05). Spontaneous complaints were noted during the bi-weekly or monthly visit and were also expressed by patients completing a self-administered questionnaire. Differences in spontaneous complaints or in the symptoms evaluated by the questionnaire were not significant. The increase in the number of symptoms at the end of the study was greater in the placebo group than in the enalapril group, but the difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Multicenter trials in the treatment of arterial hypertension. Socioeconomic repercussions].

The various therapeutic trials conducted throughout the world demonstrate the benefit of treatment even for a moderate elevation of diastolic pressure (90 or 95 mmHg). At this level of hypertension, treatment is more preventative than curative. This article discusses the benefits and the costs on the individual and collective scale in the context of two opposed strategies: mass treatment after a certain level of blood pressure or treatment of subjects at high risk of cardio-vascular disease. To achieve a collective benefit, all of the hypertensives defined in this way need to be detected, treated and followed-up in the long-term. Stimulation of the present medical system would appear to be more effective and less costly than the creation of specialized structures.

Adult↗

[Treatment of arterial hypertension. Comparative effectiveness of the day care hospital and classical hospitalization].

Four years of activity in the one-day hospital (ODH) and the several-day hospital care (SHC) of the Hypertension Clinic at the Hôpital Saint-Joseph, Paris, were evaluated and compared. All data were recorded using the computerized Artemis system. Evaluation was performed by means of two prospective studies: a controlled trial of 121 patients randomized to either ODH or SHC, and a prospective follow-up study of 633 patients. Criteria for admission to the controlled study were: diastolic BP between 95 and 120 mmHg, age between 30 and 65 years, no anti-hypertensive treatment at first visit, no major cardiovascular or renal complication and no suspicion of secondary hypertension. Similar criteria applied to the uncontrolled study. The results, assessed after 2 years, were the same in both studies, with a drop-out rate of about 15%, a mean diastolic BP lower than 95 mmHg in 80% of the patients and a bodyweight reduction of about 1 kg in obese patients. The percentage of smokers who stopped cigarette smoking was higher in the SHC groups than in the ODH groups. It is concluded that the ODH system is effective in the initial management of hypertensive patients but that greater educational efforts are needed to effectively reduce cigarette smoking in OHD patients and bodyweight excess in both OHD and SHC patients.

Adult↗