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G Chatellier

Publications and source records attributed to G Chatellier.

At least 109 records · Page 6Linked to original sources
PubMed1996

[Introduction to quantitative semiology].

Clinicians regularly confront dilemmas when ordering and interpreting diagnostic tests. This paper presents the basic principles necessary for the critical appraisal of articles about diagnostic tests. Basic notions such as sensitivity and specificity are defined. The advantages of using the newer notion of likelihood ratios are underlined. Since all these quantities are estimates of unknown true values, the method for calculating confidence intervals are reported. Finally, the simplified expression of Bayes' theorem based on the use of likelihood ratios is described alongside with a simple nomogram making it possible to calculate posttest probabilities at the bedside.

Bayes Theorem↗
PubMed1996

[Computer-assisted medical decision].

A physician deals everyday with uncertainty to take decisions and treat patients. The goal of decision making systems is to facilitate and improve the decision. Classical approaches, such as decision trees or statistical tools, provide rates about possible actions and outcomes of physicians' decisions. Such information is essentially numerical. Other computer approaches, like expert systems, provide both numeric and symbolic information. The expert knowledge is embedded in the system and used to elaborate new decisions and to provide reasoning explanations. The use of computer making decision systems will certainly increase the performances in future medical activity as it will provide a reliable additional expert information to take decisions.

Algorithms↗
PubMed1996

The DIAB-HYCAR Study.

Microalbuminuria and proteinuria are strong independent predictors for increased cardiovascular mortality in non-insulin-dependent diabetic (NIDDM) patients. In such patients, angiotensin converting enzyme (ACE) inhibition improves the evolution of diabetic nephropathy; however, no data are currently available on the effects of such intervention on cardiovascular morbidity and mortality. The aim of the Diab-Hycar study is to test the hypothesis that ACE inhibition with a low daily dose of 1.25 mg ramipril, which has no significant effect on blood pressure, may reduce cardiovascular morbidity and/or mortality in normotensive or hypertensive NIDDM patients with persistent albuminuria. Selected and followed by general practitioners, 4000 patients will receive their usual oral antidiabetic treatment and if necessary antihypertensive treatment (ACE inhibitors excluded). In addition in a randomized, double-blind trial they will be given either a placebo or 1.25 mg ramipril daily. The follow-up is currently scheduled to last 3 years. The efficacy of ACE-inhibition will be assessed by the following major end-points: cardiovascular death, sudden death, myocardial infarction, stroke, renal replacement therapy. The Diab-Hycar study started on 3 February 1995. By 1 September 1995, 11,000 urine samples were tested. The prevalence of persistent albuminuria was 23%, 964 patients were initially included in the study, with 619 eligible patients included soon after. Different strategies have been developed to record cardiovascular events correctly and to minimize the number of patients lost to follow-up.

Albuminuria↗
PubMed1996

Home self blood pressure measurement in general practice. The SMART study. Self-measurement for the Assessment of the Response to Trandolapril.

The SMART study (Self-Measurement for the Assessment of the Response to Trandolapril) was performed in general practice and enrolled 1710 patients in order to assess on a large scale the feasibility and informative value of self-measurement of blood pressure at home (SMBP), define home blood pressure (BP) levels in comparison to office readings, and determine the number of home measurements necessary to provide an accurate and precise BP value. After a 2-week washout period, patients with office diastolic blood pressure within the range 95 to 119 mm Hg received 2 mg trandolapril once daily in the morning for 4 weeks. Four days of SMBP were performed both at the end of the washout period and the end of the treatment period, with an automatic printer-equipped oscillometric device (A&D UA751). The first day values were not analyzed. Thus, the maximum number of BP measurements obtained per patient and per period was 18. Four hundred and twenty-four patients (25%) did not perform any measurements. One thousand one hundred and nine patients (65%) performed at least 4 measurements. Among them, 619 (36%) correctly performed all 18 measurements. A preference for digits 0 and 5 was detected in physicians' measurements (three consecutive values, during a single office visit). This digit preference was not found with the semiautomatic device. When the number of measurements selected for analysis was increased from 1 to 18, in the 604 patients who provided all recordings and fullfilled all protocol criteria, the standard deviation of the mean BP of the cohort was reduced by 17% for SBP and by 23% for DBP. Eighty-five percent of this reduction was already achieved by six home measurements taken at random. BP was significantly lower at home than at the office by 13 +/- 15 mm Hg for systolic BP (SBP), and 8 +/- 10 mm Hg for diastolic BP (DBP). This difference was independent of age, more marked in women (P < .001 for SBP and P < .05 for DBP), and had a Gaussian distribution. Under treatment, office SBP/DBP decreased from 166.4 +/- 14.8/101.4 +/- 5.7 mm Hg to 144.7 +/- 14.2/86.1 +/- 8.3 mm Hg, while SMBP decreased from 153.2 +/- 17.8/93.8 +/- 10.1 mm Hg to 139.4 +/- 16.4/85.1 +/- 9.5 mm Hg (all P < .0001). A major aim in research studies and individual care is to reduce BP measurements variability. This study demonstrates the ability to evaluate baseline SMBP level in two-thirds of patients previously unfamiliar with the method, the ability to evaluate treatment effect in about one-half of the patients, the improvement in the measurement precision obtained with the repetition of measures (at least six home measurements), and the absence of bias of SMBP as compared to office measurements.

Adolescent↗
PubMed1996

Diagnostic value of anti-RA33 antibody, antikeratin antibody, antiperinuclear factor and antinuclear antibody in early rheumatoid arthritis: comparison with rheumatoid factor.

The goal of this prospective longitudinal study was to determine the serological profile of early rheumatoid arthritis (RA), and to test whether antikeratin antibody (AKA), antiperinuclear factor (APF), anti-RA33 antibody and antinuclear antibodies (ANA) had an additional diagnostic value when prescribed after rheumatoid factor (RF)-detecting methods. Sixty-nine patients with early polyarthritis suggestive of RA, seen between 1991 and 1993, were included. Five autoantibodies (i.e. RF, AKA, APF, RA33, ANA) were looked for at regular intervals. After 24 months follow-up, patients were classified as having RA (n = 49), unclassified polyarthritis (UP; n = 15) or other rheumatic diseases. Among patients with early RA, the sensitivity of these markers was 40.8% for RF, 36.7% for AKA, 28.6% for APF and 28.6% for anti-RA33. Among RF-negative RA patients, 51.7% were positive for AKA, APF, anti-RA33 antibodies and/or ANA. Positivity of the three recent markers usually persisted throughout follow-up, whereas RF was lost by 58% of patients with early, RF-positive, treated RA. Using multivariate analysis, only latex, RF test and AKA or APF had an independent and statistically significant diagnostic value for early RA. Our data suggest that RF and AKA (or APF) should be concomitantly determined for diagnosis in patients with suspected early RA.

Adolescent↗
PubMed1996

Integration of trial, meta-analysis and cohort results with treatment guidelines.

IMPORTANCE OF GUIDELINES: Guidelines to medical practice are of vital importance because of the fast and uncontrolled introduction of new technologies, increasing amounts of information, including contradictory results, high levels of inappropriate care and increased financial pressure. Thus guidelines can help solve common problems in all health care systems worldwide. PREPARATION OF GUIDELINES: In preparing guidelines, a synthesis of results from the literature prepared by a single expert must be compared with syntheses done by others, and a consensus recommendation may then be issued. Such a recommendation will not be based exclusively on the results of controlled trials, even when they have indisputable internal validity. There is still a need for a value judgement within a particular psychological and socio-economic context. FREEDOM FOR PHYSICIAN: It is important to preserve the physician's freedom to prescribe drugs or not in conjunction with informed choice by the patient concerning the risks of any long-term drug intervention, even if this freedom of choice does not fit with the expectations of "managed' care or third-party payers.

Clinical Trials as Topic↗
PubMed1996

Improved survival in rats administered NG-nitro L-arginine methyl ester due to converting enzyme inhibition.

Blockade of the renin-angiotensin system (RAS) prevents the increase in blood pressure (BP) induced by chronic administration of NG-nitro L-arginine methyl ester (L-NAME) in rats. In the present study, we showed how a converting enzyme inhibitor can prevent the end-stage tissue damage due to chronic nitric oxide (NO) synthase blockade and thus improve the survival rate. Three experiments were performed. In the first, rats (n = 10) were given L-NAME (50 mg/kg) and 10 other rats were given L-NAME plus quinapril (10 mg/kg) starting 1 month after L-NAME administration. Ten untreated rats were used as controls. Rats were killed after 2 months, and the RAS, renal function, and renal morphology were analyzed. In the second experiment, a similar protocol was used, and function and morphological damage in renal slices and cervical medullary tissue were assessed after 4 months of L-NAME and 3 months of quinapril + L-NAME. In the third experiment, a similar protocol was used, but to establish survival curves, the animals were not killed. L-NAME significantly increased BP without causing any significnat changes in plasma renin activity (PRA) at 2 months. The aortic wall cyclic GMP content was significantly decreased, and the angiotensin-converting enzyme (ACE) activity was increased by L-NAME. Quinapril significantly reversed the high BP induced by L-NAME without changing the decrease in the aortic wall cyclic GMP. Two-month L-NAME treatment decreased renal function and damaged renal tissue. Quinapril prevented both proteinuria and morphological damage. Four-month L-NAME treatment induced renal end-stage damage and infarctions of the cervical medulla. Quinapril prevented this end-stage damage in the kidney and cervical medulla. Quinapril therefore prevented the increased mortality due to L-NAME. Hence, inhibition of ACE, despite its lack of effect on arterial wall cyclic GMP, does reverse the hypertension and prevent end-stage vascular damage induced by chronic L-NAME in target organs.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Self-expandable stents for the treatment of iliac artery obstructive lesions: long-term success and prognostic factors.

OBJECTIVE: The purpose of our study was to report long-term (more than 2 years of follow-up) angiographic patency after self-expandable stent implantation in the iliac artery and to identify patient- or procedure-related prognostic factors of angiographic patency. SUBJECTS AND METHODS: Ninety-five consecutive patients (101 arteries) underwent Wallstent implantation to treat claudication (n=95 limbs), rest pain (n=2), and nonhealing ulcer (n=3). Another patient was asymptomatic but was treated for acute occlusion of the iliac artery after coronary angioplasty. After implantation of self-expandable stents, we followed up by examining clinical and angiographic records at 6 months, 1 year, and annually thereafter. The Kaplan-Meier survival curve was used to determine primary and secondary patency rates. Primary patency was that achieved after the initial procedure only. Secondary patency was defined as that achieved after one or more successful additional percutaneous procedures within the stent or beyond the stent. Multivariate analysis using the Cox proportional hazard model was performed to identify predictive factors of angiographic failure, defined as restenosis of 50% or greater or occlusion. RESULTS: Four-year patency rates of 61% (primary) and 86% (secondary) were found (mean follow-up, 29 months). The following five factors were associated with long-term angiographic failure: occlusion of the superficial femoral artery (relative hazard = 5.21), absence of hypertension (relative hazard = 4.85), a stent diameter of less than 8 mm (relative hazard = 4.45), two or more stents implanted (relative hazard = 3.56), and current tobacco consumption (relative hazard = 2.46). CONCLUSION: Improved patency rates may be obtained by selecting patients for Wallstent implantation in the iliac artery based on five factors shown to be prognostically important.

Adult↗
PubMed1996

[Supratentorial gliomas: neuropsychological study of long-term survivors].

A battery of psychologic tests was administered to 32 patients, aged from 26 to 61 years, who had survived 2 years or more after treatment with surgery and radiotherapy for supratentorial gliomas (18 low grade and 14 high grade) without evidence of recurrent tumor on MRI. Two groups were identified. A first group of 17 patients had neuropsychologic scores similar to estimated premorbid level (group I). A second group of 15 patients had abnormal neuropsychologic scores, lower that their estimated premorbid level (group II). In comparison with "normal" patients, those with abnormal neuropsychologic scores were older at the time of treatment, had a lower post-operative Karnofski Performance Status, a longer delay between surgery and the date of the tests and more often had left sided lesions. Comparison of Karnofski Performance Status between the post-operative time point and the date of neuropsychological evaluation did not show a significant change over time in groups I and II except in 3 patients who experienced progressive deterioration. Vigorous treatment of gliomas with surgery, radiotherapy and sometimes chemotherapy does not induce a substantial cognitive dysfunction in about half of the long term survivors (53%). Cognitive dysfunction is identified in the other half that could be related to post-operative sequelae (due to the tumor itself or to surgery) and/or to radiotherapy- and chemotherapy-induced delayed toxicity.

Adult↗
PubMed1996

Assessment of drug efficacy using home self-blood pressure measurement: the SMART study. Self Measurement for the Assessment of the Response to Trandolapril.

UNLABELLED: The SMART study (Self Measurement for the Assessment of the Response to Trandolapril) was a large scale trial conducted by general practitioners in order to assess the informative value of home self-measured blood pressure (BP) for the evaluation of therapeutic intervention. After a 2-week wash-out period, patients with office diastolic blood pressure (DBP) between 95 and 120 mm Hg received trandolapril, 2 mg once daily for 4 weeks. Four days of self-recorded BP were performed both at the end of the wash-out period and at the end of the treatment period with an automatic printerequipped device using the oscillometric method (A&D UA 751). Every day, a series of three consecutive measurements was planned in the morning before drug intake and repeated in the evening. A total of 1710 patients (946 men, 764 women) aged 56 +/- 11 entered the study. In the 816 patients who correctly performed self-measured blood pressure (SMBP) during both periods and followed the protocol schedule, office BP (SBP/DBP) decreased from 166.4 +/- 15/101.4 +/- 6 mm Hg to 144.7 +/- 14/86.1 +/- 8 mm Hg while SMBP decreased from 153 +/- 18/94 +/- 10 mm Hg to 139 +/- 16/85 +/- 10 mm Hg. A weak correlation was found between the two methods with regard to systolic (r = 0.47, P < 0.0001) and diastolic (r = 0.36, P < 0.0001) BP lowering. Individual response to therapy varied between the two methods: 633 patients (77.6%) exhibited at least a 10 mm Hg office DBP decrease while 493 (60.4%) presented at least a 6 mm Hg self measured DBP decrease in the evening; 65% of patients were considered as responders with both methods. The 24-h therapeutic coverage was assessed by the morning to evening BP decrease ratio (M/E ratio) which represents the ratio of the trough effect to the 12-h post dosing efficacy. Both population and individual M/E ratios ranged between 73% and 86% thus confirming the long duration of action of trandolapril. IN CONCLUSION: (1) discrepancies between office and self-measured BP evaluation of therapeutic response have been pointed out: agreement between the two methods is obtained in only 65% of patients, mainly due to intra-individual BP variability and recording conditions; and (2) self-measured BP could be a potential tool to explore the 24-h therapeutic coverage.

Adolescent↗
PubMed1995

[Conn's adenoma. Diagnostic and prognostic value of the measurement of potassium, renin, aldosterone levels and the aldosterone/renin ratio].

OBJECTIVES: To evaluate diagnostic criteria in primary aldosteronism, we studied the sensitivity and specificity of potassium, renin, aldosterone and the renin/aldosterone ratio in 60 patients undergoing surgery for Conn's adenoma, 50 patients with primary hypertension and 49 normal controls. We also searched for a relationship between these parameters and the blood pressure outcome of surgery. METHODS: The diagnostic value of the tests was quantified using the Youden index after adjustment for receiver operating characteristic (ROC) thresholds. RESULTS: Potassium level in patients was lower than in controls, but in 22%, kaliemia was > or = 3.5 mmol/l and the threshold giving the best Youden index (0.93) was 3.9 mmol/l. The diagnostic power of active renin was low (Youden index 0.28), but the Youden indexes for aldosterone level and the aldosterone/renin ratio in supine position were 0.68 and 0.66 respectively. After a mean follow-up of 8.7 months after surgery, 70% of the patients had normal or improved blood pressure levels. None of the biological parameters evaluated was associated with blood pressure outcome, but age > 55 years was related to unfavorable outcome (sensitivity and specificity 80 and 60%). CONCLUSION: The threshold level requiring a search for an adenoma should be raised. When the potassium level is < or = 3.9 mmol/l the aldosterone/renin ratio should be measured in supine position since it evaluates the dissociation between renin and aldosterone seen in primary hyperaldosteronism. The effect of age on the surgical result emphasizes the importance of early diagnosis.

Adult↗
PubMed1995

Additive effects of combined angiotensin-converting enzyme inhibition and angiotensin II antagonism on blood pressure and renin release in sodium-depleted normotensives.

BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors do not decrease plasma angiotensin (Ang) II levels 24 hours after drug intake to the same extent as at peak. This intermittent partial "escape" is explained either by a renin-mediated reactive rise in plasma Ang I or by non-ACE-dependent Ang II generation. We therefore tested the hypothesis that a combination of ACE inhibition and Ang II blockade may have additive biological and hemodynamic effects. METHODS AND RESULTS: In a single-dose, double-blind, randomized, four-way, crossover study, an Ang II antagonist (losartan 50 mg), an ACE inhibitor (captopril 50 mg), their combination, and matched placebos were orally administered to 12 normotensive male volunteers maintained in mild sodium depletion. When captopril 50 mg and losartan 50 mg were given alone, the magnitude of their effects on blood pressure, plasma active renin, Ang I, and aldosterone was similar, whereas the kinetics of their effects were different, reflecting differences in drug pharmacokinetics. The losartan-captopril combination completely suppressed the rise in plasma Ang II induced by losartan 2 hours after drug intake (3.3 +/- 3.6 pg/mL versus 20.3 +/- 19.1 pg/mL, respectively, P < .05). Six hours after drug intake, the losartan-captopril combination induced a significantly greater decrease in mean blood pressure than that produced by either losartan or captopril alone (73 +/- 7 mm Hg versus 79 +/- 8 mm Hg versus 81 +/- 7 mm Hg, respectively, P < .05). The maximum placebo-subtracted falls in mean blood pressure for the losartan-captopril combination, captopril 50 mg, and losartan 50 mg were 14 +/- 5 mm Hg, 10 +/- 3 mm Hg, and 9 +/- 6 mm Hg, respectively (F2.22 = 3.45, P < .05). The duration of the mean blood pressure fall was not prolonged by the combination. After combined losartan-captopril administration, the area under the plasma active renin versus time curve (0 to 24 hours) was significantly increased when compared with either losartan or captopril alone (6404 +/- 2961 pg.h.mL-1 versus 3105 +/- 1461 pg.h.mL-1 versus 2092 +/- 867 pg.h.mL-1, respectively, P < .05). The combination had no additive effects on plasma aldosterone decrease when compared with either losartan or captopril alone (58 +/- 17% versus 51 +/- 20% versus 53 +/- 21%, respectively, NS). CONCLUSIONS: The combined administration of a standard single oral dose of an ACE inhibitor and an Ang II antagonist to mildly sodium-depleted normal subjects (1) had a major additive effect on plasma renin rise, (2) induced an additional mean blood pressure reduction, and (3) had no additive effect on plasma aldosterone fall.

Adolescent↗
PubMed1995

Which definition for echocardiographic left ventricular hypertrophy?

Left ventricular (LV) hypertrophy is diagnosed on the basis of LV mass measurement at echocardiography. However, various thresholds for defining LV hypertrophy have been published, ranging from 111 to 134 g/m2 and from 100 to 125 g/m2 in men and women, respectively. The aim of our study was to evaluate variations in the prevalence of LV hypertrophy induced by the application of different threshold values among hypertensive subjects. LV mass was calculated in 349 hypertensive patients from an M-mode LV tracing obtained by left parasternal view in 83% and by subcostal view in 17% of patients. The prevalence of LV hypertrophy ranged from 17% to 39%, according to the threshold value applied (from 10% to 47%, and from 19% to 39% in women and men, respectively). As expected, the prevalence of LV hypertrophy in obese patients of both sexes was higher when applying the usual height-indexed threshold (143 and 102 g/m for men and women, respectively) than when applying the usual body surface area-indexed threshold (134 and 110 g/m2 for men and women, respectively). The use of normalized thresholds when comparing different indexation methods (in this case, 145 g/m for men, 120 g/m for women) will minimize these variations in part due to the threshold choice. Considering the clinical and therapeutic implications associated with the presence of LV hypertrophy, better standardization of definitions is needed; this could be based either on better-designed cooperative normality studies or meta-analysis of risk stratification.

Adult↗