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

The haemodynamic and respiratory changes occurring acutely after pulmonary embolism induced in dogs were documented, and the effect of heparin and isoprenaline on the emboli and on the changes induced were also studied. Heparin led to a greater reduction in embolus weight compared to control animals, but in the short time interval of this study it did not lead to improvement, in the respiratory or haemodynamic parameters. Isoprenaline led to increased pulmonary artery flow and a reversal of changes in lung compliance. It is concluded that both these agents should be instituted as soon as possible following pulmonary embolism.
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PMID:The influence of heparin and isoprenaline on the changes produced by pulmonary embolism. 695 28

Despite venous stasis and a hypercoagulable state during pregnancy, the reported incidences of deep venous thrombosis and pulmonary embolism are remarkably low, about 1 in 2,000 and 1 in 10,000 cases, respectively. Mortality from antepartum thromboembolism has been reported in about 15 percent of untreated patients and less than 1 percent of treated patients. Adequate anticoagulant therapy significantly reduces maternal mortality and decreases postpartum morbidity. The proper anticoagulant agent for use during pregnancy has been widely debated. Coumarin compounds pass through the placenta and into the fetus. Hemorrhagic complications in the fetus are uncommon if prothrombin times are carefully controlled and if the drug is discontinued before delivery. However, coumarin during the first trimester has the teratogenic hazard of producing chondrodysplasia punctata. Heparin, in contrast, does not cross the placental barrier and is considered more effective treatment for deep venous thrombosis; however, long-term intravenous administration during pregnancy has been considered both impractical and possibly hazardous due to the risk of osteoporosis after 6 months of therapy. In our study, a combined regimen of intravenous and subcutaneous heparin was used successfully in four women with deep venous thrombosis. One patient who had recurrent embolization while on adequate intravenous heparin underwent vena caval clipping and had an uneventful Cesarian section at term with a normal infant. Another patient also underwent Caesarian section with a normal infant, while the other two women had normal vaginal deliveries at term. Miniheparin therapy was continued for 3 months postpartum, followed by long-term aspirin and Ascriptin therapy. Carefully controlled heparin therapy in a pregnant woman with deep venous thrombosis both safe and beneficial for mother and fetus.
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PMID:Management of deep venous thrombosis and pulmonary embolism during pregnancy. 709 23

Patients who are bedridden because of debilitating illness and patients who are recovering from major surgery are at particularly high risk of deep venous thrombosis and subsequent pulmonary embolism. "Mini-dose" heparin therapy has proved useful in preventing deep venous thrombosis. Because the clinical signs of pulmonary embolism are nonspecific, the patient's condition may deteriorate before the diagnosis is suspected. Ventilation and perfusion scans or pulmonary angiography confirm the diagnosis. Heparin continues to be the mainstay of therapy for pulmonary embolism.
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PMID:Pulmonary embolism. 712 79

Heparin of five commercially available brands was used to study the disappearance of heparin anticoagulant activity in normal humans. The drug was administered intravenously by bolus injection and by continuous infusion. Heparin anticoagulant activity was determined by two assays: a diluted activated partial thromboplastin time (APTT) and an assay based on inactivation of bovine factor Xa, using a clotting system. After a bolus injection, the data fitted neither single exponential nor zero-order clearance. In semilogarithmic plots, heparin anticoagulant activity disappeared according to a slightly convex curve almost always preceded by a rapid initial loss of heparin anticoagulant activity. This disappearance profile was observed with all heparin regardless of the brand or assay system. Heparin anticoagulant activity estimated by the APTT disappeared faster than heparin anticoagulant activity estimated by the anti-Xa activity in the first phase. As expected, higher anticoagulant levels with the anti-Xa assay than with the APTT were also found on continuous infusion in normals as well as in patients treated for deep vein thrombosis or pulmonary embolism. The experimental data suggested a model based on the combination of a saturable and a linear clearance mechanism. These experimental data provide reliable guidelines for adjustment of the dose of heparin in single patients.
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PMID:Kinetics of intravenously administered heparin in normal humans. 713 19

Scintigraphy with 111in-labeled autologous platelets was performed in 20 patients with suspected venous thrombosis and/or pulmonary embolism. The platelets accumulated in venous thrombi in 6 or 7 patients (86%) with positive findings on impedance plethysmography or contrast venography; all 6 were receiving intravenous heparin. In 11 patients with pulmonary embolism diagnosed by ventilation--perfusion imaging or pulmonary angiography, platelet scintigraphy showed embolic uptake only in the one patient not on full-dose heparin. These findings suggest that scintigraphy with 111In-platelets is a promising noninvasive technique for detection of deep venous thrombosis. Heparin does not appear to block localization of labeled platelets in venous thrombi, but may inhibit their adherence to pulmonary emboli.
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PMID:Scintigraphy with 111In-labeled autologous platelets in venous thromboembolism. 738 1

The authors report the observation of a new kindred with hereditary antithrombin III deficiency. In the last three generations, the family comprised 10 subjects, 7 of whom were affected: the grandmother had recurrent thrombophlebitis; her three sons died from pulmonary embolism at 22, 26 and 28 respectively and her daughter had repeated bouts of thrombophlebitis. In patients with hereditary antithrombin III deficiency, venous thrombosis occurs under similar conditions as, and is clinically similar to, thrombosis in patients without this defect. Usual tests of hemostasis are normal. The diagnosis is however suspected through an history of recurrent episodes and of similar cases in relatives. The diagnosis is confirmed by demonstration of low levels of antithrombin III in suspected patient and family. The disease is transmitted as autosomic dominant trait. Heparin is ineffective but oral anticoagulants may prevent occurence or recurrence of thrombosis in patients with this genetic defect.
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PMID:[Familial thromboembolic disease associated with antithrombin III deficiency (author's transl)]. 746 44

This study was a randomized, parallel-group, open-label clinical trial comparing the efficacy and safety of Enoxaparin, a low-molecular-weight heparin, and unfractionated heparin to prevent deep venous thrombosis after elective total knee arthroplasty. Four hundred fifty-three patients were randomized and received study medications. The primary efficacy evaluation was unilateral contrast venography done at the end of study or earlier if clinically indicated. The primary safety outcome was the incidence of bleeding episodes. Patients were assigned to 1 of 2 postoperative treatment groups: Enoxaparin 30 mg subcutaneous every 12 hours (228 patients), or unfractionated heparin 5000 units subcutaneous every 8 hours (225 patients). The incidence of proximal and distal deep venous thrombosis in the Enoxaparin group was 24.6% (56/228), and in the heparin group 34.2% (77/225). Three major hemorrhagic episodes were observed in each treatment group. Two cases of pulmonary embolism occurred in patients receiving heparin (1 fatal); no cases occurred in patients receiving Enoxaparin. This study showed that Enoxaparin administered postoperatively 30 mg every 12 hours is more effective and as safe as unfractionated heparin prophylaxis to prevent deep venous thrombosis in patients having elective total knee arthroplasty.
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PMID:Efficacy and safety of enoxaparin versus unfractionated heparin for prevention of deep venous thrombosis after elective knee arthroplasty. Enoxaparin Clinical Trial Group. 749 68

The anticoagulant agents commonly used in prevention and treatment of pulmonary embolism are unfractionated heparin, and more recently, low molecular weight heparins, and oral anticoagulants. Unfractionated heparin is the drug of choice for prophylaxis and short-term treatment of pulmonary embolism. Oral anticoagulants are used for prophylaxis in high risk patients and in long-term treatment of pulmonary embolism. Independent overview analysis of clinical trials in elective surgery showed a 60 to 70% reduction in the incidence of fatal pulmonary embolism in heparin-treated patients when they were compared with placebo-treated patients. Low dose heparin has also been shown to be effective in reducing venous thromboembolism after myocardial infarction and other serious medical disorders. In high risk patients prophylaxis with low molecular weight heparins or adjusted doses of unfractionated heparin is recommended. The objectives of treating patients with pulmonary embolism are to prevent death, to reduce morbidity from the acute event, and to prevent thromboembolic pulmonary hypertension. These objectives are achieved by the administration of heparin followed by oral anticoagulants. Heparin is generally administered for 7 to 10 days and is followed by oral anticoagulants. Although widely used and effective in the prevention and treatment of pulmonary embolism, unfractionated heparin has some pharmacological limitations. Heparin presents an aspecific "nonfunctional" binding to plasma proteins such as fibrinogen, factor VIII, vitronectin, and fibronectin. This aspecific binding limits the anticoagulant effect of unfractionated heparin and, is responsible for the heparin resistance observed in some patients with pulmonary embolism as well as of the high intersubject variability of the heparin-induced anticoagulant effect. Antithrombotic agents, such as low molecular weight heparins and pure thrombin inhibitors (hirudin and its analogues), do not specifically bind to plasma protein and they will probably improve the efficacy and practicality of the treatment of pulmonary embolism.
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PMID:Anticoagulation in the prevention and treatment of pulmonary embolism. 781 28

Triflavin, an Arg-Gly-Asp-containing snake venom peptide, inhibits platelet aggregation through the blockade of fibrinogen binding to the activated platelets. In this study, platelet thrombus formation was induced by irradiation of the mesenteric venules with filtered light in mice pretreated intravenously with fluorescein sodium. Electron microscopy reveals moderately damaged endothelial cells, as well as aggregates consisting almost exclusively of platelets with pseudopod formation, and degranulated appearance. Triflavin (10-20 micrograms/g) significantly prolonged the lag period of inducing platelet plug formation in mesenteric venules when it was intravenously infused. Triflavin (20 micrograms/g) prolonged the occlusion time about 2-fold (from control 112 +/- 23 to 240 +/- 47 s). Furthermore, PGE1 briefly prolonged the occlusion time about 1.5-fold (from 105 +/- 21 to 168 +/- 20 s) when it was given by continuous infusion (40 micrograms/kg/min). On the other hand, triflavin was also effective in reducing the mortality of ADP-induced acute pulmonary thromboembolism in mice when administered intravenously at dose of 2-4 micrograms/g. Heparin (1.5 U/g) and indomethacin (200 micrograms/g) had no significant effect in prolonging the occlusion time or in reducing ADP-induced pulmonary embolism in mice. Therefore, triflavin is an effective antithrombotic agent in preventing the thromboembolism in these two in vivo models.
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PMID:In vivo antithrombotic effect of triflavin, an Arg-Gly-Asp containing peptide on platelet plug formation in mesenteric microvessels of mice. 787 41

An audit was performed to examine the time of administration of heparin and antibiotic prophylaxis to patients at risk of deep vein thrombosis, pulmonary embolism and post-operative wound infection. The records of 648 consecutive patients undergoing major surgery within a 12-month period were reviewed retrospectively. Heparin prophylaxis was given before surgery to only 30.9 per cent of patients undergoing elective procedures and in only 22.7 per cent of emergencies. Antibiotic prophylaxis was given before operation or at induction of anaesthesia to 82.1 per cent of patients undergoing elective procedures and in only 72.1 per cent of emergencies. It is concluded that administration of heparin and antibiotic prophylaxis is inadequate despite the provision of a written protocol.
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PMID:Administration of heparin and antibiotic prophylaxis. 782 48


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