Biomedical subjects

C Vasilakis

Publications and source records attributed to C Vasilakis.

23 records · Page 2Linked to original sources

PubMed1995

Risk of idiopathic cardiovascular death and nonfatal venous thromboembolism in women using oral contraceptives with differing progestagen components.

Concern about the risks of cardiovascular illness in women using combined oral contraceptives (OC) containing the progestagens desogestrel and gestodene prompted two studies of data from the UK General Practice Research Database. We compared the risks of certain cardiovascular illnesses in otherwise healthy women exposed to one of three OCs containing < 35 micrograms oestrogen plus levonorgestrel, desogestrel, or gestodene. In the first study, based on some 470 general practices, there were 15 cases of unexpected idiopathic cardiovascular death among 303,470 women who were current users of one of the study OCs. The estimated incidence rates were 8/184,536 (4.3 per 100,000) woman-years at risk for users of combined OCs containing levonorgestrel, 2/135,567 (1.5 per 100,000) for desogestrel users, and 5/105,201 (4.8 per 100,000) for gestodene users. The relative risk (RR) estimates were 0.4 (95% CI 0.1-2.1) and 1.4 (CI 0.5-4.5) for desogestrel and gestodene, respectively, compared with levonorgestrel. In the second study, derived from some 370 general practices, there were 80 cases of nonfatal venous thromboembolism (VTE) in a cohort of 238,130 otherwise healthy women. The incidence rates of VTE per 100,000 woman-years at risk were 16.1 for levonorgestrel users, 29.3 for desogestrel, and 28.1 for gestodene. The adjusted RR estimates from the cohort analysis were 1.9 (1.1-3.2) and 1.8 (1.0-3.2) for desogestrel and gestodene users, respectively, compared with users of levonorgestrel. In a nested case-control analysis the adjusted matched RR estimates were 2.2 (1.1-4.4) and 2.1 (1.0-4.4) for desogestrel and gestodene users, respectively, compared with users of levonorgestrel. The excess risk for nonfatal VTE associated with the new generation of combined OCs containing low-dose oestrogen and the progestagens desogestrel or gestodene compared with levonorgestrel is estimated to be 16 per 100,000 woman-years.

Adult↗

PubMed1993

Percutaneously placed dual-lumen silicone catheters for long-term hemodialysis.

Dual-lumen Dacron-cuffed silicone hemodialysis catheters placed percutaneously under fluoroscopic control have been used by us in 200 patients since July 1986. A total of 246 catheters were placed in 4 years, of which 172 were for long-term hemodialysis in place of prosthetic tube bridge arteriovenous shunts. One-year catheter survival estimate by Kaplan-Meier life table was 57 per cent, and mean survival estimate was 16.3 months. There were a combined 76 patient years of catheter experience, with some catheters lasting as long as 2 1/2 years. Catheter thrombosis occurred in 92 catheters, but 83 per cent of cases responded to thrombolytic therapy. There were exit site infections with thirty-nine catheters, but 90 per cent resolved with antibiotic therapy. Twenty-two bacteremias occurred with 19 catheters, which resulted in 15 catheter removals. The remaining seven cases of bacteremia responded to antibiotic therapy without catheter removal. Subclavian vein or superior vena cava thrombosis has not been a problem. Silicone catheters are a practical alternative to prosthetic tube bridge arteriovenous shunts for long-term hemodialysis.

Adolescent↗

PubMed1990

Use of a silicone dual-lumen catheter with a Dacron cuff as a long-term vascular access for hemodialysis patients.

We evaluated our experience over a 4-year period with a silicone dual-lumen catheter with a Dacron cuff (SDLCDC) to determine if the catheter represents an alternative to the polytetrafluoroethylene graft for long-term vascular access for hemodialysis patients. Records of 131 patients who used 168 catheters were reviewed for catheter function, duration of use, and occurrence and response to treatment of complications. Eighty-five percent of catheters functioned adequately until their use was no longer required or the end of the study. One-year catheter survival estimate was 65% and median survival estimate was 18.5 months. Mean blood flow rate achieved was 243 mL/min and recirculation was 7.5%. Exit-site infection occurred in 21% of patients and bacteremia in 12%. There were significantly more exit-site infections in diabetics than nondiabetics (33% v 11%, P less than 0.02). Exit-site infections resolved with parenteral antibiotic therapy in 90% and bacteremia in 25% of cases without catheter removal. Unresolved bacteremia was the most common cause of catheter removal and led to the loss of 7% of catheters. Thrombotic complications occurred in 46% of catheters. Urokinase instillation successfully treated catheter occlusion in 81% of cases. When urokinase instillation failed, streptokinase infusion restored catheter patency 97% of the time. The literature on the polytetrafluoroethylene (PTFE) graft was reviewed, and the SDLCDC was found to be similar to the graft in function, duration of use, and frequency of infectious and thrombotic complications. We conclude that the catheter represents an alternative to the graft for long-term vascular access in hemodialysis patients. Because of the frequent complications with both accesses, neither should be considered optimal. Further research is required to improve vascular access for patients in whom placement of an arteriovenous fistula is not possible.

Bacterial Infections↗

PubMedDate not supplied

The risk of myocardial infarction associated with antihypertensive drug treatment in persons with uncomplicated essential hypertension.

We conducted a case-control study based on computer-recorded information accrued in the United Kingdom General Practice Research Database to assess and compare the relation between different antihypertensive drug therapies and myocardial infarction in patients with no known clinical or laboratory risk factors for myocardial infarction other than hypertension. Cases were treated hypertensive patients with no other known risk factors who developed a first acute myocardial infarction between January 1, 1993, and October 31, 1994. They were ascertained from a review of the clinical record together with a questionnaire filled out by the attending general practitioner. Controls were matched to each case for age, sex, general practice, and index date. Antihypertensive therapy was derived from the computerized patient record. The study consisted of 210 cases and 793 controls. Compared with users of beta-blockers alone, the adjusted relative risk (RR) estimates for all other treatment regimens were close to 1.0. A comparison of users of calcium channel blockers alone with users of beta-blockers alone yielded a RR estimate of 0.9 (95% CI 0.5, 1.7). We conclude that the risk of acute myocardial infarction in otherwise healthy, treated hypertensive patients is not materially associated with the particular drug they receive.

Adult↗

PubMedDate not supplied

The risk of seizures associated with tramadol.

We conducted a study of the risk of idiopathic incident seizures among users of tramadol derived from data present in the General Practice Research Database based in the United Kingdom for 1994-1996. We used a nested case-control study design, comparing risks of idiopathic incident seizures during exposed and unexposed times among patients who had ever taken tramadol using a 90-day follow-up. Among the 10,916 subjects, we identified 17 cases of idiopathic seizures, 11 of which were definite and 6 possible. None of the patients was exposed to tramadol alone in the prior 90 days. Eight patients were exposed to opiates, five to both tramadol and opiates, three to other analgesics, and one to no analgesics. We found no increased risk of idiopathic incident seizures associated with exposure to tramadol alone. Thus seizures seem rarely attributable to the agent.

Adolescent↗