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

Blood samples from 24 patients who received recombinant human tissue-type plasminogen activator (rt-PA) for angiographically documented acute pulmonary embolism were examined to identify and quantify fibrinolysis. Before and after the intravenous administration of 50 mg rt-PA over a 2 hr period, levels of total fibrinogen, fibrin(ogen) degradation products (FDP), and cross-linked fibrin degradation products (XDP) were measured in each patient. Elevated levels of XDP were found in all patients before treatment (mean 2.0 micrograms/ml, normal less than 0.2 microgram/ml), and these increased 12-fold with treatment. Fibrinogen levels fell 30% and FDP levels increased 24-fold for the entire group of patients. Over this 2 hr period, 10 of 24 patients (responders) demonstrated 25% or greater improvement in the extent of pulmonary artery thrombus as quantified by Urokinase Pulmonary Embolism Trial score, and these patients were found to have a significantly lower XDP/FDP ratio after rt-PA (p less than .04) than those patients who failed to respond. These data suggest that the intravenous administration of pharmacologic doses of rt-PA in patients with pulmonary embolism produces both fibrinolysis and fibrinogenolysis, successful thrombolysis in these patients is associated with a preponderance of fibrinogenolysis over fibrinolysis, the XDP/FDP ratio is a useful indicator of fibrinolytic specificity, and in patients with acute pulmonary embolism the endogenous fibrinolytic pathways are activated, albeit ineffectively, as indicated by the increased circulating XDP levels seen in all 24 patients before the administration of rt-PA.
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PMID:Recombinant tissue plasminogen activator in patients with pulmonary embolism: correlation of fibrinolytic specificity and efficacy. 310 14

The use of fibrinolytic agents to control the fibrinolytic enzyme system and lyse pathologic fibrin deposits or thrombus has now assumed a position with anticoagulants and vascular surgery in the physician's therapeutic armamentarium. The principal exogenous activators that are used clinically are streptokinase, urokinase, and tissue plasminogen activator. Acute arterial occlusions are more likely than chronic occlusions to respond to thrombolytic therapy, especially if treatment is instituted within a few hours of onset of symptoms and if the disease is due to embolic material rather than in situ thrombosis. Since the duration of drug infusion necessary to lyse arterial thrombus cannot be predicted, patients in whom tissue viability cannot be determined or in whom ischemia cannot be tolerated during the drug infusion interval are not candidates for intraarterial fibrinolytic drug infusion. In treating patients with venous occlusion, thrombolytic therapy is more effective against proximal clots than in calf thrombosis. No protective effect from pulmonary embolism has been noted in trials comparing heparin with streptokinase. Fifty percent of patients with an initial episode of deep venous thrombosis treated within 72 hours of onset will have complete resolution of thrombus with preservation of valve function.
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PMID:Application of thrombolytic therapy in vascular occlusive disease. A surgical view. 311 28

To determine if pulmonary perfusion was improved in acute pulmonary embolism after therapy with recombinant human tissue-type plasminogen activator (rt-PA), lung scans were obtained before and a mean of 22 hours after therapy in 19 patients. The posttherapy lung scans were compared with baseline, pretherapy scans with use of two semiquantitative methods--an anteroposterior view method, similar to that used in the Urokinase Pulmonary Embolism Trial, and a segmental method that emphasized pulmonary anatomy. There was an improvement in the defect score from 0.35 to 0.14 (P less than .01) when the anteroposterior view method was used and from 0.37 to 0.16 (P less than .01) when the segmental method was used. These encouraging results in the early posttherapy period suggest that rt-PA is especially effective in improving regional perfusion after pulmonary embolism and that a larger controlled trial of therapy with rt-PA for acute pulmonary embolism should be performed. Scoring lung scans with a segmental method is feasible and appropriate for present-day lung scan technique and should be considered in future studies.
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PMID:Pulmonary perfusion after rt-PA therapy for acute embolism: early improvement assessed with segmental perfusion scanning. 312 66

The fibrinolytic system is activated by the conversion of plasminogen to plasmin by mediators such as tissue extract, plasma factor XII, or the exogenous activators urokinase (UK) and streptokinase (SK). The foreign protein composition of SK is responsible for the allergic response observed in some patients following administration. Clinical and investigational evidence has also shown a higher incidence of hemorrhagic complications with SK compared with UK. In general, thrombolytic therapy is a safe, effective way to resolve thrombotic obstruction in patients with such problems as acute pulmonary embolism, acute myocardial infarction, or occluded intravascular lines.
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PMID:Fundamentals of fibrinolytic therapy. 313 Oct 5

Pulmonary embolism is diagnosed 120,000 times yearly in the United States and contributes to 30,000 deaths. This probably represents an underestimate of incidence because massive acute pulmonary embolism may often result in rapid and therefore unexplained death in the absence of autopsy confirmation. The innovative and judicious use of thrombolytic agents by emergency department and paramedical ambulance personnel may lead to a decreased mortality for this disease. Clinical studies are necessary to determine if the cardiopulmonary compromise associated with massive pulmonary embolism can be rapidly reversed through thrombolysis and whether that reversal will lead to increased survival. The use of thrombolytic agents will gain favor only if their risk:benefit and cost:benefit ratios are acceptable. We discuss the results of using first- and second-generation thrombolytic agents in the treatment of pulmonary embolism and review the encouraging data that have emerged from our studies with recombinant tissue-type plasminogen activator (tPA). This agent has relative fibrin specificity and may provide therapeutic advantages over the conventional thrombolytic agents, urokinase and streptokinase, particularly when the latter are administered in the currently recommended dose schedules for treatment of pulmonary embolism.
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PMID:Acute pulmonary embolism treated with thrombolytic agents: current status of tPA and future implications for emergency medicine. 314 20

Thrombolytic therapy of pulmonary embolism reduces total pulmonary resistance more rapidly than heparin alone. In massive pulmonary embolism this hemodynamic benefit usually outweighs the moderately increased bleeding risk if contra-indications are strictly observed. Practical dosage regimens for streptokinase and urokinase are proposed.
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PMID:[Thrombolysis in acute massive lung embolism]. 317 66

Pulmonary embolism following postoperative deep venous thrombosis is a very serious complication with a high mortality rate. Though this disorder has been thought to be rare in Japanese, its occurrence seems to be increasing recently because of changes in eating habits, increase of average age and the frequent practice of venous catheterization. Two cases of the pulmonary embolism following deep venous thrombosis after surgery are reported, and possible causes of the deep venous thrombosis are discussed. Case 1: A 48 year-old obese female was operated on for a posterior fossa dural arteriovenous malformation. On the 4th postoperative day, she developed a pain and swelling in the left leg and low back pain. On the 18th postoperative day, she fell into a state of shock following the sudden onset of a severe back pain and respiratory distress. After diagnosis of the pulmonary embolism, she was immediately treated with urokinase, warfarin and aspirin. Her obesity was considered to be one of the risk factors of the postoperative deep venous thrombosis. Case 2: A 62 year-old female with a ruptured cerebral aneurysm could not get out of bed because of postoperative mental disturbance. A central venous pressure catheter was inserted into the right femoral vein for two weeks postoperatively. One month after surgery, she complained of swelling and a dull pain in the right leg without cardiorespiratory symptoms. Lung perfusion scintigraphy showed asymptomatic pulmonary embolism. She was treated immediately. Both long bed rest and femoral venous catheterization were considered as risk factors possibly leading to deep venous thrombosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Postoperative pulmonary embolism in neurosurgical practice: report of two cases]. 321 Dec 80

Since the introduction of thrombolytic treatment based on the activation of plasminogen (PLG) by streptokinase (SK) and urokinase (UK) the search for new and improved methods has been continuing. The pivotal issue is how to achieve clot-specific fibrinolysis without producing systemic fibrinogenolysis. One out of various approaches to enhance lysis rates has been the use of PLG either alone or in combination with UK or SK in the light of the fact that fibrinolytic treatment, particularly using SK, is associated with a consumption of PLG, and that thrombi contain relatively small amounts of native PLG, however, are capable of incorporating added PLG in vitro. PLG-concentrates from various manufactures have been administered intravenously for treatment of deep venous thrombosis, mainly in combination with SK, and of pulmonary embolism in combination with UK. Local intracoronary and intraarterial administration in combination with UK has been reported in patients with myocardial infarction, and peripheral arterial occlusions, respectively. Lysis rates obtained in these studies were in most cases superior to results obtained with SK or UK alone, without increasing the incidence of bleeding complications. In addition, excellent results in larger group of patients with cerebral thrombosis were obtained with PLG alone. The encouraging results of these studies may be explained by the fact that all of the preparations used contained partially activated forms of PLG (commonly designated lys-PLG) to a greater or lesser extent. Lys-PLG has a higher affinity for fibrin than the native glu-PLG and is activated by UK or SK by a manyfold faster. These properties allow for a rapid formation of plasmin which--bound to fibrin--is also protected from the attack of neutralizing antiplasmin. The design and results of previous studies with lys-PLG concentrates will be reviewed and approaches to further improve fibrinolytic regimens with lys-PLG-concentrates discussed.
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PMID:Review of studies with plasminogen concentrates and proposals for further therapeutic strategies with plasminogen concentrates. 328 Apr 22

Early attempts to treat thromboembolic disorders focused on the prevention of thrombus formation, along with the prevention of extension and/or embolization of an existing thrombus. Antithrombotic therapy for these conditions included intravenous and oral anticoagulants and later antiplatelet agents, all of which remain in use today. Subsequent research sought a thrombolytic agent that could lyse a clot directly. Intravenously administered streptokinase and urokinase were found to act on the inactive proenzyme plasminogen to produce the active enzyme plasmin that could safely and effectively lyse fresh fibrin clots. These agents have proved effective for the treatment of myocardial infarction and pulmonary embolism, as well as peripheral arterial and venous thromboembolic conditions. Recent efforts have been directed toward a search for clot-specific agents that would avoid the systemic lytic state associated with the use of urokinase and streptokinase. Three clot-specific plasminogen activators are currently being evaluated: recombinant tissue-specific plasminogen activator, anisoylated streptokinase plasminogen activator complex, and pro-urokinase.
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PMID:Historical overview of antithrombotic and thrombolytic therapy. 330

Use of urokinase to treat heparin-associated thrombocytopenia and thrombosis in one patient is described, and various treatments proposed for this syndrome are discussed. A 56-year-old man received an intravenous bolus dose of heparin sodium at his local hospital and was transferred to another institution for treatment of suspected pulmonary embolism; he had received heparin two weeks earlier during coronary angiography. The patient's platelet count was reported to be normal before heparin administration. When embolism was confirmed, heparin was discontinued and streptokinase was given for 24 hours. Heparin infusion was then restarted at 1000 units/hr and continued for four days. Platelet count on admission to the second hospital was 47,000/cu mm; 12 hours later it was 19,000/cu mm, and it remained low despite platelet transfusions. Five days after admission, deep-vein thrombosis developed in the left leg. Heparin was discontinued and urokinase and warfarin were started. Urokinase was infused at 320,000 IU/hr for 12 hours and continued at dosages of 160,000-320,000 IU/hr for a total of 40 hours. The initial warfarin sodium dose was 15 mg, followed by a dosage of 10 mg/day. Symptoms of deep-vein thrombosis improved within 12 hours and platelet count increased after heparin was discontinued. If it is recognized early enough, heparin-associated thrombocytopenia can be reversed by discontinuation of heparin. Transfusions of platelets are of little benefit. Dipyridamole, cyclo-oxygenase inhibitors such as aspirin, and protamine sulfate may be useful. Long term anticoagulation with warfarin is recommended to prevent recurrent thrombosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thrombolytic therapy in heparin-associated thrombocytopenia with thrombosis. 348 69


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