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

Thrombus formation depends on adherence of blood-formed elements to the intimal surface through platelet-vessel surface interaction, platelet release phenomena and aggregation, formation of fibrin, and the enmeshing of blood cells. Arterial thrombi involve platelet aggregation, whereas venous thrombi found in low flow or during stasis have greater proportions of erythrocytes and fibrin. It is not known if or how abnormalities of flow resistance, platelet thrombus formation, or endothelial and dynamic parameters affect the microcirculation, largely due to the difficulty of obtaining comprehensive data from these systems. Increases of fibrinogen observed in many disorders may result in minor changes in blood viscosity without known physiologic consequence, but in most disorders in which thrombosis is observed, the pathophysiologic mechanisms are multifactorial and abnormal blood viscosity is presumed to be a significant but not limiting component. Therapeutic approaches in thrombotic disorders should recognize which elements of the thrombotic triad predominate. In arterial disorders focus should be on platelet activity, and the objectives of venous thrombosis treatment include prevention of morbidity and death from pulmonary embolism, reduction of morbidity resulting from the acute thrombotic episode, and prevention of the postphlebitic syndrome. Pathology, mechanism, and treatment for specific thrombogenic disorders are described. Treatments suggested for hyperviscosity involve giving antibiotics during crises. Also discussed are thalassemia, paroxysomal nocturnal hemoglobinuria, polycythemia, cryoglobulinemia, paraproteinemia, diabetes mellitus, and disseminated intravascular coagulation. Studies have established a relationship between thromboembolic disease and oral contraceptives (OCs). The risk is only increased while the patient is taking OCs but is compounded in women undergoing surgery or who have a disorder which predisposes to venous disease. The risk for myocardial infarction or stroke is significantly increased when OCs are taken over age 35 and when there is hypertension, smoking, type-II hyperlipoproteinemia, and diabetes mellitus. The risk appears to be a function of estrogen dosage, causing a 25% mean increase in calf venous volume and 30% decrease in vein velocity of venous blood compared to controls. Low flow rates may contribute to venous thromboembolism. OCs may alter precisely regulated systems of coagulation and fibrinolysis and recent studies confirm abnormalities in the hemostatic system attributed to OCs. 16% of women taking OCs have a 60% or greater reduction in antithrombin III activity. The multiple effects of OCs often result in low-grade activation of the hemostatic system, potentially lowering the threshold to precipitate thrombus formation and possibly explaining the increased incidence of thromboembolic disease. Heparin appears to reverse many of these problems.
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PMID:Blood viscosity and thrombosis: clinical considerations. 676 12

We reviewed the current techniques and published results of balloon-occluded retrograde transvenous obliteration (B-RTO) for gastric varices (GV) and hepatic encephalopathy. The portal hemodynamics of gastric varices were classified into three types according to their feeding vessels, and the development of collateral veins under balloon occlusion of gastro-renal shunt was classified into five grades. The main draining veins of gastric varices were gastro-renal and gastro-inferior phrenic shunts. Preprocedural diagnosis of portal hemodynamics is important in selecting the technique for B-RTO. The rate of disappearance or marked reduction of GV was 98%, and the rate of recurrence of GV was 2%. Hepatic encephalopathy due to gastro-renal shunt improved markedly. In contrast, esophageal varices were aggravated at rates of 10% to 62.5% by the post-procedural elevation of portal pressure. Common adverse effects were hemoglobinuria, abdominal pain, and low-grade fever, but ascites and pleural effusion were also reported. Severe complications such as cardiogenic shock, atrial fibrillation, and pulmonary embolism were reported. We await technical improvements and further indications for this procedure.
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PMID:[Balloon-occluded retrograde transvenous obliteration (B-RTO) for portal hypertension]. 1092 Dec 94

Sclerotherapy with absolute ethanol and/or polidocanol is a well-established therapeutic modality for the treatment of peripheral vascular malformations, although systemic complications such as hemoglobinuria and pulmonary embolism could occur. We report two cases of pulmonary embolism associated with sclerotherapy for peripheral vascular malformations. Two patients, a 17-year-old man and a 17-year-old woman, undergoing absolute ethanol sclerotherapy for vascular malformations of the leg developed pulmonary embolism after injection of ethanol. Pulmonary embolism, suspected by the clinical symptoms such as hypoxia and hypocapnia, was confirmed by the pulmonary scintigraphy showing minimal pulmonary defects. Hemoglobinuria was also observed with injection of ethanol. Patients recovered rapidly with heparin and urokinase therapy. The review of perioperative complications with sclerotherapy for peripheral vascular malformations in our institution for past four years revealed that complications were observed in 18 out of 88 patients (20.5%), and in 32 out of 183 cases (17.5%). Major complications were hemoglobinuria, pulmonary embolism, shivering and delayed emergence from general anesthesia. We conclude that sclerotherapy for vascular malformations under general anesthesia is a risky procedure and this must be carefully managed with keen monitoring of Spo2 and Etco2.
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PMID:[Pulmonary emboli in sclerotherapy for peripheral vascular malformations under general anesthesia; a report of two cases]. 1524 36

Symptomatic slow-flow vascular malformations include venous malformations and lymphatic malformations, as well as combined anomalies. Endovascular therapy, consisting mainly of intralesional sclerosant injection, is now accepted as the primary treatment for most of these lesions. Magnetic resonance imaging and ultrasonography supplement physical examination for diagnosis and assessment of the extent of malformation. Endovascular treatment is usually carried out under general anesthesia. Sclerosants for venous malformations include ethanol, 3% sodium tetradecyl sulfate, and bleomycin. Lymphatic malformations can be injected with doxycycline, bleomycin, OK-432, or other sclerosants. Complications of sclerotherapy include tissue necrosis, peripheral nerve injury, hemoglobinuria, deep vein thrombosis, and pulmonary embolism. Although most vascular malformations are not cured, the majority of patients benefit from endovascular treatment.
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PMID:Endovascular treatment of slow-flow vascular malformations. 2349 28

Percutaneous mechanical thrombectomy (PMT) has been gaining acceptance as a preferred approach for the treatment of acute deep venous thrombosis (DVT). In addition to treating acute DVT and decreasing the risk of pulmonary embolism, it has been reported that direct extraction of the thrombus decreases the risk of post-thrombotic syndrome (PTS), the economic impact of managing which is reported to account for 75% of the total cost of management of DVT patients. PMT combines localized thrombolysis with mechanical thrombectomy. Recently, there have been some reports of reversible acute kidney injury (AKI) occurring post-PMT. The pathophysiology of AKI in such cases is due to hemoglobinuria-associated acute tubular necrosis. Therefore, the overall prognosis of AKI post-PMT has been reported to be good. We report here a case of AKI post-PMT for an extensive DVT of the lower extremity whereby the patient continues to require HD even 5 months after the procedure. The patient had normal renal function prior to the procedure and evidence of hemoglobinuria at the time of diagnosis of AKI. Our case illustrates that patients with a large thrombus load may develop severe AKI post-PMT thus requiring hemodialysis for an extended period of time. Limiting the length of time that the mechanical thrombectomy is performed and quantifying the amount of effluent obtained would appear to be a prudent practice to reduce the risks of renal failure. However, no specific guidelines exist as for the limits of hemolysed exudates to be collected.
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PMID:Prolonged renal failure post-percutaneous mechanical thrombectomy. 2594 90