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Biomedical subjects

D Clement

Publications and source records attributed to D Clement.

At least 19 recordsLinked to original sources
PubMed1998

Ambulatory blood pressure monitoring and postprandial hypotension in elderly patients with isolated systolic hypertension. Systolic Hypertension in Europe (SYST-EUR) Trial Investigators.

The present analysis was undertaken to evaluate postprandial (PP) changes in blood pressure (BP) assessed with ambulatory BP monitoring (ABPM) in elderly subjects with isolated systolic hypertension (ISH) on conventional measurement. A total of 530 patients (335 women and 195 men, aged 60-100 years, median 70 years) who performed an ABPM during the placebo run-in period of the Syst-Eur trial were included into the analysis. The PP changes in BP and heart rate (HR) were calculated by subtracting the mean systolic BP (SBP), diastolic BP (DBP) and HR in the 2 h preceding the main meal from the corresponding means covering the 2 h after the meal. The reproducibility of the postprandial fall in BP and heart rate (PPH) was assessed by contrasting the first and second ABPM in a subgroup of 147 patients who performed two ABPM's during the placebo run-in period. The mean SBP and DBP decreased and reached the nadir 2 h after the main meal while HR did not change. When PPH was assessed by comparing BP in the 2 h before and after the meal, both SBP and DBP decreased significantly (respectively -6.6 mm Hg, -5.4 mm Hg; P < 0.001). In 67.6% of all patients a decrease in SBP was observed and in 24.1% it exceeded 16 mm Hg. The corresponding values for DBP were 71.3% and 24.5% (DBP decreased more than 12 mm Hg). A greater fall in DBP was associated with a greater decrease in HR (r = 0.20, P < 0.001), while changes in SBP and HR were not interrelated. Regression analysis did not identify any significant covariate of PPH. Group means of PPH could be reproduced without significant changes in their values, but the within-subject reproducibility of the PP changes was low. There were no differences in PPH according to the place of residence of the patients. In conclusion, the descriptive analysis of the meal-induced changes in ABPM in elderly subjects with ISH showed that in every day circumstances most of them experience falls in both SBP and DBP within 2 h after the meal.

Aged↗
PubMed1997

Perioperative management of colon cancer under Medicare risk programs.

OBJECTIVE: To determine differences in perioperative care and outcomes for patients with colon cancer enrolled in Medicare health maintenance organizations compared with similar fee-for-service nonenrollees. METHODS: Cross-sectional evaluation of hospital care and posthospital outcomes with data obtained from medical records. Nineteen health maintenance organizations representing all model types were selected from 12 states. The nonenrollee sample was drawn from the same areas. The sample included 412 enrollees and 401 nonenrollees, representing 65 hospitals for health maintenance organizations and 61 hospitals for fee-for-service. RESULTS: Nonenrollees were slightly older and had higher preoperative risk. Enrollees had shorter intervals between admission and surgery (enrollees, 1.55 days vs nonenrollees, 2.85 days). Differences in length of stay (enrollees, 10.9 days vs nonenrollees, 14.2 days) persisted even after controlling for preoperative health status. Differences in admissions to intensive care units (enrollees, 36.4% vs nonenrollees, 44.4%) were highly influenced by preoperative health status. Nonenrollees were more significantly likely to receive preoperative antibiotics, postoperative testing (eg, postoperative chest radiographs and electrocardiograms), and postoperative patient-controlled analgesia. Tumor staging was similar for both groups. Enrollees were more likely to be discharged home, while nonenrollees were more likely to be discharged to a nursing home. There were no significant differences in hospital deaths or postdischarge readmissions. CONCLUSIONS: Health maintenance organization enrollees with colon cancer received less clinical services of several types than similar patients in fee-for-service settings, had shorter hospital stays, and were less likely to be discharged to nursing homes. However, there was no evidence that they experienced different outcomes.

Aged↗
PubMed1997

Determining the trough-to-peak ratio in parallel-group trials. Systolic Hypertension in Europe (SYST-EUR) Trial Investigators.

We explored how in parallel-group trials interindividual variability, correction for placebo effects, and smoothing of blood pressure profiles can be handled in measuring the trough-to-peak ratio in 244 individuals with isolated systolic hypertension (> or = 60 years) enrolled in the placebo-controlled Systolic Hypertension in europe Trial. Net treatment effects were computed by subtracting the mean changes from baseline during placebo (n = 133) from those during active treatment (n = 111). At entry, systolic/diastolic pressures averaged 176/86 mm Hg in the clinic and 149/80 mm Hg on 24-hour ambulatory monitoring. With corrections applied for baseline and placebo, nitrendipine (10 to 40 mg/d), with the possible addition of enalapril (5 to 20 mg/d) and/or hydrochlorothiazide (12.5 to 25 mg/d), reduced (P < .001) these blood pressure values by 16.6/7.3 and 9.8/4.7 mm Hg, respectively. The net trough-to-peak ratios were first determined from blood pressure profiles (12 hours) with 1-hour precision, synchronized by the morning and evening doses of the double-blind medication. According to the usual approach, disregarding interindividual variability, the systolic/diastolic net trough-to-peak ratios were 0.46/0.40 in the morning and 0.77/0.99 in the evening. In individual subjects, the baseline-adjusted trough-to-peak ratios were nonnormally distributed. We therefore used a nonparametric technique to calculate the net trough-to-peak ratios from the results in individual subjects. In the morning, these ratios averaged 0.25 systolic (95% confidence interval, 0.09 to 0.41) and 0.15 diastolic (95% confidence interval, 0.00 to 0.31) and in the evening, 0.19 and 0.36 (95% confidence intervals, 0.00 to 0.38 and 0.14 to 0.56), respectively. When the blood pressure profiles were smoothed by substituting the 1-hour averages by moving or fixed 2-hour averages or by Fourier modeling, the trough-to-peak ratios remained unchanged after the morning dose (0.20/0.13, 0.20/0.14, and 0.16/0.21, respectively) but tended to increase in the evening (0.32/0.38, 0.28/0.40, and 0.48/0.49). In conclusion, the parallel-group analysis proposed makes it possible for one to correct the trough-to-peak ratio for baseline as well as placebo, to account for interindividual variability, and to calculate a confidence interval for the net trough-to-peak ratio. Accounting for interindividual variability reduces the trough-to-peak ratio. Smoothing affects the individualized net trough-to-peak ratios in an unpredictable way and should therefore be avoided.

Aged↗
PubMed1997

Mission possible.

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Africa, Eastern↗
PubMed1997

Tri-calcium phosphate ceramics and allografts as bone substitutes for spinal fusion in idiopathic scoliosis as bone substitutes for spinal fusion in idiopathic scoliosis: comparative clinical results at four years.

The authors present the results of a comparative study of two series of posterolateral arthrodeses for scoliosis performed using COTREL DUBOUSSET instrumentation. Fifty-four consecutive patients underwent surgery for idiopathic scoliosis using the same technique. Thirty received a graft consisting of a mixture of corticocancellous autologous and allogenic bone frozen at -80 degrees, and 24 patients were grafted with a mixture of cortico-cancellous autologous bone and sticks of tricalcium phosphate (TCP, Biosorb, SBM, Lourdes, France). All patients were seen at three, six and twelve months, then once a year for at least four years with clinical and radiological evaluation at each visit. At the final follow up visit, no radiologic signs of pseudoarthrosis were found in either group with a minimum follow-up of 4 years. The appearance of bone callus was considered satisfactory at 6 months in all cases; moreover callus seemed to be more important in the TCP series, although this assessment was subjective. TCP resorption was total after 2 years, while allograft fragments were visible on x-rays after 2 years. Minor mechanical complications occurred but did not influence the results. Loss of correction was 8% of that initially obtained in the allograft group and 2% in the TCP group. Loss of correction did not progress after 6 months in the TCP group and after 2 years in the allograft group. Based upon this experience, the use of synthetic bone substitutes such as TCP would appear to be a valuable alternative to allografts in posterolateral spinal arthrodesis for idiopathic scoliosis, and it would eliminate the risk of viral contamination inherent to allograft implantation. To our knowledge, there have been no previous comparative studies concerning the use of tricalcium phosphate versus allograft in the literature.

Adolescent↗
PubMed1996

Hyperbaric oxygen chambers and the treatment of sports injuries.

Hyperbaric oxygen therapy, an established therapeutic intervention in diving medicine, is being investigated in wound management, where oxygen is an integral part of the healing process. Currently, the evidence is controversial as to whether there is a basis for using hyperbaric oxygen in normal wounds. This review explains the rationale for the use of hyperbaric oxygen therapy and reports on the initial research in the area of hyperbaric oxygen in sports-induced injury. In addition to the increased dissolved content of oxygen in the plasma, the combination of pressure and oxygen seems to promote systemic vasoconstriction and yet inhibition of vasoconstriction in the injured area, which will limit oedema. The safety of hyperbaric oxygen in otherwise healthy athletes is examined. Potential contraindications to hyperbaric oxygen therapy include individuals who are febrile, suffer from upper respiratory infections, or have suffered a trauma to the chest where a pneumothorax is suspected or have a predisposition to tension pneumothorax. The initial human and animal model studies have shown promising, and in some instances significant, acceleration of healing. The potential benefits for sports injuries appear to be a blunting of initial injury, possibly by controlling the neutrophil adhesion and release of oxygen free radicals as well as an enhancement of healing processes requiring oxygen-like collagen formation phagocytosis.

Animals↗
PubMed1996

Antihypertensive therapy in older patients with isolated systolic hypertension: the Syst-Eur experience in general practice

Background and objective. This interim report from the Syst-Eur trial investigated the level of blood pressure control achieved during the double-blind period in patients followed in general practices. Methods. In the Syst-Eur trial elderly patients (60 years or older) with isolated systolic hypertension were randomized to either active or placebo treatment. Active treatment consisted of nitrendipine combined with enalapril and/or hydrochlorothiazide to reduce systolic pressure to Results. This analysis was restricted to patients of general practitioners who had been followed for at least 12 months. The placebo (N = 204) and active treatment (N = 217) groups had similar characteristics at randomization. At one year, the difference in sitting pressure between the two treatment groups was 10 mmHg systolic and 4 mmHg diastolic. Fewer patients remained on monotherapy in the placebo than in the active treatment group and on placebo the second and third line medications were started earlier. Nitrendipine tablets were discontinued in 10 patients on placebo and in 21 patients assigned to active treatment (P Conclusions. A significant blood pressure reduction can be achieved and maintained in older patients with isolated systolic hypertension followed by general practitioners. Whether this blood pressure reduction results in a clinically meaningful decrease of cardiovascular complications is under investigation. Keywords. Antihypertensive treatment, general practice, isolated systolic hypertension, randomized clinical trial.

Journal Article↗
PubMed1996

Trading places.

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Acculturation↗
PubMed1996

Antihypertensive therapy in older patients with isolated systolic hypertension: the Syst-Eur experience in general practice. The Syst-Eur Investigators.

BACKGROUND AND OBJECTIVE: This interim report from the Syst-Eur trial investigated the level of blood pressure control achieved during the double-blind period in patients followed in general practices. METHODS: In the Syst-Eur trial elderly patients (60 years or older) with isolated systolic hypertension were randomized to either active or placebo treatment. Active treatment consisted of nitrendipine combined with enalapril and/or hydrochlorothiazide to reduce systolic pressure to < 150 mmHg and by > or = 20 mmHg. Matching placebos were used in the control group. RESULTS: This analysis was restricted to patients of general practitioners who had been followed for at least 12 months. The placebo (N = 204) and active treatment (N = 217) groups had similar characteristics at randomization. At one year, the difference in sitting pressure between the two treatment groups was 10 mmHg systolic and 4 mmHg diastolic. Fewer patients remained on monotherapy in the placebo than in the active treatment group and on placebo the second and third line medications were started earlier. Nitrendipine tablets were discontinued in 10 patients on placebo and in 21 patients assigned to active treatment (P < 0.001 for all comparisons). CONCLUSIONS: A significant blood pressure reduction can be achieved and maintained in older patients with isolated systolic hypertension followed by general practitioners. Whether this blood pressure reduction results in a clinically meaningful decrease of cardiovascular complications is under investigation.

Aged↗
PubMed1996

The John Charnley Award. Natural history of thromboembolic disease after total hip arthroplasty.

In 1079 consecutive patients undergoing total hip arthroplasty between 1984 and 1992, complications of thromboembolic disease and related anticoagulation were reviewed for 6 months after hospital discharge, including cost data. Of 347 patients having venograms, 78 (22.5%) had positive results and 269 (77.5%) had negative results for deep venous thrombosis. In patients with negative venograms, 3 (1.1%) were readmitted with 2 symptomatic deep venous thromboses and nonfatal pulmonary embolism. There were no readmissions among the 55 patients who had venographically evident deep venous thrombosis diagnosed and treated with outpatient warfarin. Overall, 3 of 324 (0.9%) patients with true positive or negative venograms were readmitted for complications of thromboembolic disease. In contrast, 12 of 732 (1.6%) patients not receiving contrast venography were readmitted, including 9 (1.2%) deep venous thromboses and 3 (0.4%) nonfatal pulmonary embolisms. Four of 23 patients (17.4%) with untreated calf deep venous thrombosis suffered 2 nonfatal pulmonary embolisms resulting in readmission and 2 fatal pulmonary embolisms outside the hospital. Untreated calf deep venous thrombosis after total hip arthroplasty represents a significant threat of extension to more proximal veins and distant embolization. Routine thromboembolic disease prophylaxis combined with screening contrast venography and selective therapeutic anticoagulation is effective in preventing late thromboembolic disease complications and, compared with a strategy of extended prophylaxis for all, is cost effective management by reducing exposure of the elderly population to outpatient anticoagulant therapy.

Aged↗
PubMed1995

Influence of porosity on the mechanical resistance of hydroxyapatite ceramics under compressive stress.

Calcium phosphate ceramics are biocompatible and may develop interactions with human living bone tissues. They are used clinically on the surface of orthopaedic implants to improve primary fixation or in the form of porous blocks. Their brittleness is often advanced as a limitation of their common clinical use. In order to study the influence of porosity on the mechanical strength of calcium phosphate ceramics, we have tested 150 cylindrical hydroxyapatite samples with open porosity. The total porous volume of the ceramics has been varied from 20% to 60% and the pore size from 5 microns to 400 microns. The result indicates that not only total porosity but also pore size can influence compressive strength, which is in good agreement with theoretical work. After mathematical treatment of the results, the experiments have been modelled in the form of a polynomial equation which can be used to predict and optimize mechanical strength. Moreover, this work supports the fact that compressive strength of controlled open porosity implants can be comparable with that of cancellous or cortical human bone, and suggests that porosity should be fitted to clinical application.

Ceramics↗