PubMed · 2534481
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S Córdova, S Dorantes-Mesa, J Pizzuto, G Ruiz-Argüelles, R A Izaguirre-Avila. [Thrombosis].. https://pubmed.ncbi.nlm.nih.gov/2534481/
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Gabexate mesylate, a non-antigenic synthetic inhibitor of trypsin-like serine proteinases, is a drug used efficiently in the treatment of pancreatitis and disseminated intravascular coagulation and as a regional anticoagulant for haemodialysis. Considering the structural similarity between L-arginine and gabexate mesylate, the effect of this drug on L-arginine transport, nitric oxide (NO) formation and constitutive NO synthase activity in human platelets was investigated. Data have shown that gabexate mesylate inhibited competitively L-arginine uptake by increasing the K(m) value from 22+/-2 to 86+/-6 microM. The K(i) value was 158 microM at pH 7.4 and 37 degrees. Furthermore, gabexate mesylate decreased dose and time-dependent nitrite and nitrate formation (NO(x) release) and cGMP accumulation in whole cells. In addition, gabexate mesylate inhibited constitutive nitric oxide synthase in a cell-free extract. We concluded that gabexate mesylate could be considered an effective modulator of cellular NO synthesis.
BACKGROUND: Prophylaxis of venous thromboembolism with low-molecular-weight heparins in patients undergoing major orthopedic surgery is currently initiated according to at least 3 different regimens. In Europe, traditionally, prophylaxis is started 12 hours before surgery, whereas in North America it is initiated 12 to 48 hours postoperatively. The third regimen (perioperative) begins prophylaxis either earlier than 12 hours before or 12 hours after surgery. Unfortunately, the optimal regimen is uncertain because direct comparisons among these regimens with sufficiently large sample sizes are not available. OBJECTIVE: To assess, in a systematic review, the relative efficacy and safety of the 3 low-molecular-weight heparin regimens used to prevent thrombosis after total hip replacement. The incidence of postoperative thrombosis detected by contrast venography was used as the measure of efficacy and the rate of major bleeding was used as the measure of safety. METHODS: We pooled the results of all published studies, which met the following criteria: (1) inclusion of in at least 1 arm of the study of a dose of low-molecular-weight heparin that is approved for both preoperative and postoperative initiation of prophylaxis; (2) the use of mandatory bilateral contrast venography, performed between days 6 and 15 postoperatively; (3) thromboprophylaxis continued until venography; (4) independent reading of venograms; and (5) assessment of clinically overt major bleeding by predefined criteria. Articles were excluded if no separate data could be obtained for patients undergoing elective hip surgery (in case of patient mix), or if they were reported more than once. RESULTS: In the 1926 patients who used a preoperative regimen, the incidence of postoperative deep vein thrombosis was 19.2% (95% confidence interval [CI], 17%-21%). In the cohort of 925 patients who received a perioperative regimen, the rate of deep vein thrombosis was 12.4% (95% CI, 10%-14%), whereas in the group of 694 patients who received a postoperative regimen, it was 14.4% (95% CI, 12%-17%). The rate of major bleeding was 1.4% (95% CI, 1%-2%) in the preoperative group, 6.3% (95% CI, 5%-7%) in the perioperative group, and 2.5% (95% CI, 1%-3%) in the postoperative group. CONCLUSIONS: We find no convincing evidence that starting prophylaxis preoperatively is associated with a lower incidence of venous thromboembolism than starting postoperatively. Perioperative regimens may lower the risk of postoperative thrombosis, but if so, this positive effect is offset by an increase in postoperative major bleeding.
BACKGROUND: The prevalence of asymptomatic deep vein thrombosis diagnosed by venography after hip or knee replacement remains high despite 7 to 10 days of anticoagulant prophylaxis. However, the risk of symptomatic events in such patients is unclear. We performed a meta-analysis to provide reliable estimates of the risk of symptomatic venous thromboembolism occurring within 3 months of hip or knee replacement in patients who received short-duration (7-10 days) anticoagulant prophylaxis. METHODS: The MEDLINE, EMBASE, and Cochrane databases were searched from January 1993 to March 2001, supplemented by a manual search of bibliographies and conference abstracts, to identify prospective studies of patients undergoing hip or knee replacement who received short-duration prophylaxis (ie, 7-10 days of fixed-dose low-molecular-weight heparin or adjusted-dose warfarin, with a target international normalized ratio of 2.0-3.0). Studies were classified as clinical outcome studies if the outcome was symptomatic venous thromboembolism or as venographic outcome studies if the outcome was asymptomatic deep vein thrombosis diagnosed after bilateral venography. RESULTS: There were 4 clinical outcome studies with 6089 patients who had 3 months of follow-up, and 13 venographic outcome studies with 7080 patients who had venography 7 to 10 days after surgery. In clinical outcome studies, the 3-month incidence of nonfatal venous thromboembolism was 3.2% (95% confidence interval [CI], 2.0%-4.4%), and the 3-month incidence of fatal pulmonary embolism was 0.10% (95% CI, 0.02%-0.20%). The postprophylaxis incidence of nonfatal venous thromboembolism was 2.2% (95% CI, 1.4%-3.0%), and the incidence of fatal pulmonary embolism was 0.05% (95% CI, 0%-0.12%). The postprophylaxis incidence of symptomatic venous thromboembolism was higher after hip than after knee replacement (2.5% vs 1.4%; P=.02). In venographic outcome studies, the prevalence of deep vein thrombosis (total and proximal) was higher after knee than after hip replacement (total: 38.8% vs 16.4%; P<.001; proximal: 7.6% vs 3.8%; P<.001). CONCLUSIONS: In patients who undergo hip or knee replacement and receive short-duration anticoagulant prophylaxis, symptomatic nonfatal venous thromboembolism will occur in about 1 of 32 patients and fatal pulmonary embolism will occur in about 1 of 1000 patients within 3 months of the surgery. Although the prevalence of asymptomatic deep vein thrombosis is more than 2-fold higher after knee replacement than after hip replacement 7 to 10 days after surgery, in the subsequent 3 months, symptomatic venous thromboembolism is more likely to occur after hip replacement.