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Query: UMLS:C0034065 (pulmonary embolism)
 14,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The value of prophylaxis against venous thromboembolism (VTE) is increasingly accepted in most surgical specialties, although the potential reduction in fatal pulmonary embolism has recently been questioned. The burden of VTE in hospital patients nevertheless remains high, partly attributable to underuse of thromboprophylaxis and partly attributable to occurrence of VTE in high-risk patients because recommended antithrombotic therapies fail to provide full protection. Improved physician education has been shown to increase the application of antithrombotic measures, and research efforts are focused on developing novel antithrombotic agents with greater efficacy and safety in clinical use. Several novel indirect and direct thrombin inhibitors have been investigated. The heparinoid danaparoid has shown superiority over unfractionated heparin in several indications, but only the recombinant hirudin, desirudin, has exhibited greater efficacy than low-molecular-weight heparin (LMWH) in thromboprophylaxis for patients undergoing elective hip-replacement surgery, without increasing the risk of bleeding. Three large-scale clinical trials have shown desirudin to be the most effective thromboprophylactic agent currently available in elective hip-replacement surgery; this agent has now been licensed for use in orthopedic surgery. Research is ongoing into the feasibility of still more effective and convenient therapies, such as oral antithrombins.
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PMID:The potential role of new therapies in deep-vein thrombosis prophylaxis. 1144 40

We examined 17 total hip arthroplasty patients in order to develop a method for the predictive diagnosis of pulmonary embolism (PE) after joint arthroplasty. Scintigraphy revealed the presence of PE in 4 patients. Prothrombin time (PT), activated partial thromboplastin time (aPTT), antithrombin III (ATIII), and thrombin-AT III complex (TAT) did not show significant differences between patients with and without PE. D-dimer 7 days after surgery showed significant differences between patients with and without PE. Fibrin monomer (FM) increased sharply after surgery, and it was significantly different between the patients with and without PE immediately after surgery and 2 days after surgery. Our findings suggest the importance of FM in the predictive diagnosis of pulmonary embolism after total hip arthroplasty, and 40 microg/ml or higher levels with our measurement method could represent a high-risk condition.
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PMID:Fibrin monomer could be a useful predictor of pulmonary embolism after total hip arthroplasty: preliminary report. 1148 95

Venous thromboembolism is a common complication in patients with cancer. The management of deep vein thrombosis and pulmonary embolism can be a considerable challenge in patients with cancer. The cancer itself and associated treatments contribute to an ongoing thrombogenic stimulus, while cancer patients are thought to be at increased risk for anticoagulant-induced bleeding. Initial treatment of acute thromboembolism is with intravenous unfractionated heparin or subcutaneous low molecular weight heparin. Treatment at home with low molecular weight heparin is an attractive option in patients with malignant disease. Long-term treatment of acute venous thromboembolism has traditionally been with oral anticoagulants. However, the inconvenience and narrow therapeutic window of oral anticoagulants make such therapy unattractive and problematic in cancer patients. Low molecular weight heparins are being evaluated as an alternative for long-term therapy because their anticoagulant effects are more predictable and laboratory monitoring is unnecessary. Although many clinical issues remain unresolved in the treatment of cancer patients with venous thromboembolism, the future holds much promise as new antithrombotic agents, including factor Xa antagonists and oral thrombin inhibitors, are being tested in clinical trials.
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PMID:Treatment of venous thrombosis in the cancer patient. 1154 81

Low-molecular-weight and unfractionated heparins are frequently used to treat venous thromboembolism, but it is not known whether they are equally effective in inhibiting in vivo generation of thrombin. In this multicenter trial, 1048 patients were randomized to intravenous unfractionated heparin (group A), twice daily low-molecular-weight heparin (reviparin) for 1 week (group B), or once daily reviparin for 4 weeks (group C). All patients received vitamin K antagonists. Blood samples withdrawn at the baseline and at weeks 1 and 3 were analyzed using markers of in vivo thrombin generation and other coagulation parameters. During the first 3 weeks symptomatic recurrent deep vein thrombosis-pulmonary embolism (DVT/PE) occurred in 17 (4.5%) of 375 patients in group A compared with 4 (1.0%) of 388 patients in group B, and 9 (2.4%) of 374 patients in group C. Forty percent of patients in group A, 53.4% in group B, and 53.5% in group C showed 30% or greater reduction in thrombus size assessed by venography. Patients in group B had significantly greater reduction in D-dimer, prothrombin fragments 1 and 2 (F1 + 2), endogenous thrombin potential (ETP), and thrombin-antithrombin (TAT) complexes compared to groups A and C. Greater release of tissue factor pathway inhibitor (TFPI) and reduction in levels of thrombin activatable fibrinolysis inhibitor (TAFI) and fibrinogen were significantly more pronounced in group C patients. Reviparin administered twice daily plus vitamin K antagonist is more effective in inhibiting in vivo thrombin generation compared to intravenous unfractionated heparin plus vitamin K antagonist, and reviparin once daily produced significantly higher TFPI release and greater reduction in TAFI and fibrinogen levels.
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PMID:Randomized trial of different regimens of heparins and in vivo thrombin generation in acute deep vein thrombosis. 1187 67

Deep venous thrombosis is a possible complication of indwelling central venous catheters (CVC), with an incidence as high as 61%. We report a case of successful thrombolysis of a CVC-related right atrial thrombus in a pediatric cancer patient with recombinant human tissue plasminogen activator (0.1 mg/kg per h for 12 h) and heparin (10 IU/kg per h for 24 h) administered for 6 days. Daily echocardiographic examination showed progressive lysis of the thrombus. The thrombolytic treatment was associated with mild oozing from the venipuncture sites, but no major bleeding was noted; moreover, thrombin, thromboplastin time and fibrinogen were normal or only minimally altered. Anticoagulant therapy, with or without CVC removal, is the treatment of choice for uncomplicated CVC-related thrombosis. Fibrinolytic therapy may be indicated in some cases at risk of pulmonary embolism or to avoid open heart surgery. Recombinant human tissue plasminogen activator is increasingly used for thrombolytic treatment of organ and limb thrombosis, but experience with it in the pediatric hematology-oncology setting is still limited. This report showed that administering recombinant human tissue plasminogen activator in a pediatric cancer patient prior to hematopoietic stem cell transplantation was effective and safe under strict biochemical and instrumental monitoring. Further studies are needed to determine the best antithrombotic treatment for CVC-related thrombosis, and also the dosage of the medication selected and the duration of treatment.
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PMID:Successful treatment of a catheter-related right atrial thrombosis with recombinant tissue plasminogen activator and heparin. 1190 91

In the final step of the clotting cascade coagulation factor XIII (FXIII) is activated by thrombin. The activated enzyme (FXIIIa) has an important role in the final stage of blood coagulation in cross-linking soluble fibrin to a stable insoluble clot. The role of FXIII in cardio- and cerebrovascular diseases has been investigated recently. The widespread Val34Leu polymorphism in the gene coding for the FXIII subunit A (FXIII Val34Leu) has been shown to protect against myocardial infarction and ischemic stroke, but is also associated with an increased risk for hemorrhagic stroke. Additionally, FXIII Val34Leu is supposed to be protective against pulmonary embolism and deep vein thrombosis. As possible mechanisms for the antithrombotic effect, premature depletion of the mutant protein from circulation and altered fibrin structures of clots cross-linked by the mutant FXIIIa are under discussion. The connection between FXIII and the insulin resistance syndrome also attracts attention, i.e. the interaction between a component of the coagulation cascade and thus a thrombotic risk factor and classical atheromatous risk factors. Therefore, FXIII must be considered as another coagulation factor contributing to complex interactions between genes and environment important for the pathogenesis of cardio- and cerebrovascular and thromboembolic diseases.
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PMID:[Role of coagulation factor XIII in cardio- and cerebrovascular diseases]. 1219 86

Identification of risk factors for incident venous thromboembolism and predictors of recurrent venous thromboembolism and appropriate antithrombotic prophylaxis and therapy are vital to improve survival after pulmonary embolism and prevent complications such as venous stasis syndrome after deep-vein thrombosis. Risk stratification is increasingly important; future prophylaxis and treatment strategies should be targeted to the patients who will derive the greatest benefit. For established antithrombotic agents, the most appropriate dose, dosing schedule, and duration of prophylaxis and therapy are being refined. In addition, new antithrombotic agents such as the oral direct thrombin inhibitors are being identified and developed. The management of acute arterial thrombosis (for example, acute coronary syndromes) is an important and relatively new indication for antithrombotic agents such as the low-molecular-weight heparins and the platelet glycoprotein IIb/IIIa antagonists.
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PMID:Mapping out the future in venous thromboembolism and acute coronary syndromes. 1223 21

The recent observation that knock-out of protease-activated receptor-4 (PAR4) ablates thrombin signaling in mouse platelets and protects against ferric chloride-induced thrombosis of mouse mesenteric arterioles suggests that thrombin's actions on platelets can play an important role in thrombosis. Complete ablation of thrombin signaling would be difficult to achieve in human beings because human platelets have 2 thrombin receptors that are each capable of mediating transmembrane signaling. However, it is possible that complete ablation of thrombin signaling in platelets is not necessary for an antithrombotic effect. In mouse platelets, PAR3 functions as a cofactor that binds thrombin and promotes productive cleavage of PAR4, and thrombin responses are decreased but not absent in Par3(-/-) platelets. We now report that Par3(-/-) mice were protected against ferric chloride-induced thrombosis of mesenteric arterioles and against thromboplastin-induced pulmonary embolism. Surprisingly, Par3(-/-) and Par4(-/-) mice showed similar degrees of protection in these models and similar prolongation of tail bleeding times. Thus, even a partial decrease in mouse platelet responsiveness to thrombin protected against thrombosis and impaired hemostasis in some settings. These results demonstrate the importance of PAR3's unusual cofactor function and underscore the relative importance of thrombin's actions on platelets in vivo. They also suggest that PAR inhibition might be explored for the prevention or treatment of thrombosis in human beings.
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PMID:Protection against thrombosis in mice lacking PAR3. 1238 23

The combination of unfractionated heparin or low molecular weight heparin and oral anticoagulants is currently the treatment of choice for most patients with venous thromboembolism. Oral anticoagulants are started at the same time and heparin is discontinued after at least 5 days when the levels of the International Normalized Ratio reach the therapeutic range between 2.0 and 3.0. Low molecular weight heparin has potential advantages over heparin and is administered in subcutaneous weight-adjusted fixed doses without need for monitoring. This has made the home treatment of a large proportion of patients possible. Randomized clinical trials and several subsequent reports from clinical practice have demonstrated the efficacy and safety of this approach. The results of currently ongoing trials aimed to assess the efficacy and safety of newer compounds for the initial treatment of venous thromboembolism are expected. Oral direct thrombin inhibitors or selective factor-Xa inhibitors have the potential to become the treatment of choice in the next decade. The optimal duration of the secondary prophylaxis with oral anticoagulants is still a matter of debate. The rate of recurrence has been shown to be elevated, particularly in patients with idiopathic venous thromboembolism. A 3-month therapy is therefore currently recommended when a transient risk factor is identified, life-long treatment is recommended for patients with a second episode of venous thromboembolism. The presence of active cancer or a thrombophilic state may require long-term anticoagulation, although not all the congenital hypercoagulable states seem to carry the same level of risk. In all other cases, 6 months are recommended, but a long-term monitoring of the patients is advisable. The use of more aggressive strategies such as thrombolysis is limited to patients presenting with massive pulmonary embolism or signs of right ventricular dysfunction.
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PMID:Treatment of venous thromboembolism. 1243 Aug 98

Patients undergoing orthopedic surgery, particularly total hip replacement procedure belong to a group of patients with a high risk of thromboembolic complications. Postoperative deep vein thrombosis may occur in 40-80% of these patients. 4-19% of patients develop clinically evident pulmonary embolism and approximately 7% of cases in this group result in death. A thorough evaluation of coagulation disorders in the perioperative period could lead to detecting risk factors of thromboembolic complications development and could facilitate more effective prophylaxis management. The aim of the study was to evaluate the dynamics of selected blood coagulation and fibrinolysis parameters in patients undergoing total hip replacement surgery. The study included 66 patients undergoing total hip replacement surgery. The group consisted of 51 women and 15 men, within the age range of 47-78, the mean age was 64. In 32 (group A) patients surgery was performed with the use of normovolemic hemodilution, in 34 (group B) the hemodilution procedure was not applied. The patients received low molecular heparin as prophylaxis started 12 hours prior surgery and continued for 5 weeks after. The examination of the coagulation system was performed: in the morning on the day of the operation--examination 1, on the day of the operation in the evening--examination 2, and on the first day after operation--examination 3. We determined the concentrations of thrombin-antithrombin complexes (TAT), prothrombin fragments 1 + 2 (F1 + 2), D-dimers (DD) and plasminantiplasmin complexes (PAP). In all the patients an ultrasound examination of the lower limbs by Doppler method was performed before the surgery and 10-12 days after the procedure. Significant activation of coagulation and fibrinolysis was found in all patients before surgery. 12 hour after the procedure a progressive increase of coagulation disorders was observed. After 24 hours marked decrease of coagulation parameters was noted. In group A significantly less thromboembolic complications was observed. On the basis of the performed examinations the following conclusions were drawn. (1) during total hip replacement surgery and particularly during the period of the first 12 hours after procedure, marked activation of coagulation and fibrinolysis occurred. (2) the application of the hemodilution procedure does not influence significantly the degree of coagulation and fibrinolysis disorders in the perioperative period.
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PMID:[Evaluation of selected parameters of blood coagulation and the fibrinolysis system in patients undergoing total hip replacement]. 1251 38


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