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Query: UMLS:C0149871 (deep vein thrombosis)
 12,364 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oral anticoagulants are used extensively, although their risks are not always fully recognized. The prophylaxis of venous thrombosis after hip surgery, the prevention of deep venous thrombosis and pulmonary emboli after an acute episode of these, the prevention of arterial emboli from the heart in patients at risk, and the prophylaxis of thrombosis in patients with congenital deficiency of antithrombin III, protein C, or protein S are some of the indications for oral anticoagulant use. Warfarin sodium is contraindicated in pregnancy, however. The recommended prothrombin time is 1 1/2 to two times control, lower than previously. The major risk of oral anticoagulant therapy, bleeding, is treated with vitamin K or plasma, depending on its severity. Warfarin necrosis and the "purple-toe" syndrome are seen more frequently than realized.
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PMID:Current concepts of warfarin therapy. 351 25

Venous thromboembolism produces chronic sequelae in the legs and occasional immediate mortality due to pulmonary embolism. Because it occurs in certain high risk situations (for example, after surgery) its prevention is a practical proposition. This has been attempted using many different approaches. Administration of low dose heparin with or without dihydroergotamine to enhance venous return has been one of the most widely tested regimens. There is little doubt that this can prevent, in many patient groups, postoperative deep venous thrombosis and fatal pulmonary embolism, with a low incidence of adverse reactions. Some particularly high risk postoperative patient groups (for example, those undergoing hip surgery) warrant more aggressive measures to prevent thrombosis. Surveys have shown that increasing use is being made of this approach, and it is hoped that all surgeons will adopt a policy that will reduce postoperative venous thrombosis and pulmonary embolism. A reduction in the incidence of venous thromboembolism in large acute myocardial infarction is achieved by low dose heparin, although early mobilization is important. In addition, many of the patients at risk merit full dose anticoagulation to prevent intracardiac thromboembolism. Established venous thrombosis is treated effectively by intravenous heparin, followed by warfarin to keep the prothrombin time at 1.2 to 1.5 times control, as assessed using rabbit thromboplastin; most patients need three months of treatment. Anticoagulation is warranted for pulmonary embolism, with fibrinolytic therapy reserved for patients with massive embolism and hemodynamic compromise. Embolectomy is a heroic measure, which may occasionally be lifesaving.
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PMID:Preventive and therapeutic approach to venous thromboembolic disease and pulmonary embolism--can death from pulmonary embolism be prevented? 353 67

Numerous investigators have postulated that a hypercoagulable state exists in humans for a period of time before the development of thrombotic episodes. A clear biochemical definition of the prethrombotic state, however, has proved elusive due in part to the lack of reliable techniques for monitoring pertinent changes in blood coagulability. Based on recent advances in our knowledge of the biochemistry of the coagulation system, a series of highly sensitive and specific immunochemical tools has been developed that can quantitate the activities of various steps of the hemostatic mechanism in vivo at the subnanomolar level. We have established assays for F1+2 and the protein C activation peptide, which measure the cleavage of the prothrombin molecule by factor Xa and the scission of protein C by the thrombin-thrombomodulin complex, respectively. Nossel and coworkers had previously constructed similar assays for fibrinopeptide A (FPA) and fragment B beta 1-42, which monitor the cleavage of fibrinogen by thrombin and the proteolysis of fibrin I by plasmin, respectively. Substantial elevations in the levels of these markers have been found in patients with disseminated intravascular coagulation and many subjects with acute deep venous thrombosis. The F1+2 and FPA assays have been used to demonstrate that significant increments in factor Xa activity but not thrombin activity regularly occur in the blood of nonanticoagulated individuals with congenital deficiencies of antithrombin or protein C. These two disorders are known to be correlated with the subsequent development of thrombosis. Patients with protein C deficiency have also been noted to have significantly reduced plasma levels of protein C activation peptide. By using the immunoassays for FPA and B beta 1-42 in studies of postoperative patients, it has been shown that an imbalance between the procoagulant action of thrombin and the anticoagulant effect of plasmin on fibrin I polymer may induce an acquired thrombotic diathesis. Finally, we have recently demonstrated that prothrombin activation as measured by the F1+2 assay is suppressed by oral anticoagulants in the blood of patients with thrombotic diatheses. These investigations suggest that these assay techniques can be used to improve our understanding of the hypercoagulable state as well as to develop more effective treatment strategies for the prevention of thromboembolic events.
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PMID:The pathophysiology of the prethrombotic state in humans: insights gained from studies using markers of hemostatic system activation. 360 75

A 57 year old man presented with apparently spontaneous lower extremity deep vein thrombosis and pulmonary embolism. He was treated in conventional fashion with intravenous heparin and oral warfarin. After 4 daily doses of warfarin the prothrombin and proconvertin (P+P) time was within therapeutic range, and heparin was stopped. Over the next six hours complete defibrination occurred, associated with severe bleeding complications. Functional protein C measured after normalization of routine coagulation tests averaged 40% of normal, and was only 3.5% of normal immediately prior to the episode of defibrination. We conclude that the very low functional protein C levels seen immediately prior to defibrination were caused by a combination of pre-existent protein C deficiency and warfarin therapy, and directly predisposed to defibrination once heparin was stopped, despite "therapeutic" warfarin anticoagulation. Exacerbation of intravascular coagulation should be considered a potential prothrombotic effect of warfarin therapy in protein C deficient individuals.
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PMID:Defibrination during warfarin therapy in a man with protein C deficiency. 383 6

The aim of these studies was to investigate different regimens of thrombolytic therapy and oral anticoagulation, and to evaluate the effects of streptokinase (SK), heparin and warfarin in the treatment of deep vein thrombosis (DVT). Low-dose SK, although controlled according to the fibrinogen levels, did not provide improved thrombolysis compared to conventional high-dose SK, and more postthrombotic changes were registered after an average of 3 years. Furthermore, serious hemorrhagic side-effects occurred, which makes this regimen inexpedient. Various regimens of local venous infusion of SK were tried, and with a dose of 4,000 IU/h for 72 h in combination with heparin a thrombolytic effect was achieved, albeit not greater than usually observed with conventional SK. Systemic hypofibrinogenemia and hemorrhage were not avoided. A hitherto not described side-effect with bullous dermatitis was reported. Venographic severity of calf vein thrombosis displayed a statistically significant correlation to long-term hemodynamic changes, as assessed with foot volumetry, after an average of 5 years. This correlation was stronger for the size of the thrombus after initial treatment than for the size at diagnosis. Thus it seems important to treat calf vein thrombosis with heparin in order to limit the extent of the thrombus, thereby reducing long-term sequelae. During heparin treatment, an average reduction of the thrombi of 17% was observed. This reduction was significantly correlated to a short duration of symptoms but not to parameters of heparin therapy or fibrinolytic components. However, patients with substantial thrombolysis had high plasmin-alpha 2-antiplasmin (PAP) levels, and those with high tissue plasminogen activator (t-PA) inhibitor levels and remarkably also those with high t-PA antigen levels had no lysis. The concentration of t-PA antigen showed a significant increase during heparin infusion, whereas that of PAP and t-PA inhibitor was not influenced. By applying more intensive initial oral anticoagulation, stable therapeutic prothrombin time (PT)-levels were achieved one day earlier and the duration of heparin infusion could be equally reduced compared to the conventional regimen (4.4-5 days vs 5.4-6 days). The activity of coagulation factors II, VII, IX and X had dropped to the same level with both regimens the day heparin was discontinued, observed. The effectiveness of oral anticoagulation after DVT was studied in 596 patients treated for a total of 4450 months.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Studies on the medical treatment of deep vein thrombosis. 391 82

The frequency of thromboembolic recurrencies during secondary prophylaxis after DVT was retrospectively studied and related to the intensity of the oral anticoagulation. All patients receiving oral anticoagulation after DVT at our hospital during April 1972-May 1980 were studied. Treatment was given to 596 patients for 724 thrombotic events for a total of 4450 months. Thirty-six thromboembolic complications, all objectively verified, occurred. Patients with cancer had complications throughout the entire range of anticoagulation. Patients without neoplastic disease (15 events) never had complications below a prothrombin complex level of 27% as assessed with Simplastin A, corresponding to a BCT-ratio of 1.9. This study confirms, that the lower limit of the therapeutic range, determined by the risk of thromboembolic complications, should be set at a Simplastin A-level of approx. 25% corresponding to BCT 2.0.
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PMID:Relationship between thromboembolic complications and intensity of treatment during long-term prophylaxis with oral anticoagulants following DVT. 399 13

Resolution of thrombi entrapped in Greenfield vena caval filters is a primary mechanism for maintenance of caval patency with this device following an embolic event. In order to determine if anticoagulation is beneficial in this setting, thrombus was harvested from 65 mongrel dogs with infrarenal IVC thrombosis after phenolization. These thrombi were weighed and embolized into Greenfield filters placed above the renal veins. The infrarenal IVCs were then ligated and the animals allowed to recover. Beginning the first postoperative day, animals were given either oral coumadin daily to elevate the prothrombin time above 1.5 normal, subcutaneous heparin 500 u/kg/day divided into two doses, or received no treatment. They were sacrificed either 1, 2, 3, or 4 weeks after embolism and the residual thrombi weighed. Initial thrombus weights were similar for each period (differences NS). Comparison of initial with final weights revealed that both coumadin and heparin-treated animals had a significantly increased resolution in the first week when compared to controls. By 2 weeks, however, there were no significant differences between the groups, and controls proceeded to a mean of 95% resolution by 4 weeks. A general linear model used to separate the effects of treatment, time, and initial thrombus weight showed that resolution was primarily a function of initial thrombus weight, and of time. Coumadin was marginally beneficial. Thrombus resolution proceeds rapidly in this model without anticoagulation. These data suggest that prevention of deep vein thrombosis and its sequelae remain the sole indication for anticoagulation after filter placement.
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PMID:Effect of anticoagulation on the lysis of filter entrapped thromboembolism in dogs. 399 33

In a randomized, prospective trial of 100 patients, we have studied the safety and efficacy of warfarin sodium in comparison with that of dextran 40 in the prevention of venous thrombosis in patients at high risk for deep vein thrombosis after elective total hip or knee replacement. Warfarin was given in a new two-step regimen designed to avoid bleeding complications while still preventing venous thrombosis. A low dose of warfarin was started ten to 14 days preoperatively, and the prothrombin time was regulated to between 1.5 and 3 seconds longer than control at the time of surgery; immediately after surgery, the dose was increased to prolong the prothrombin time to 1.5 times control. The overall incidence of venous thrombosis as documented by venography was less in the 53 patients treated with warfarin than in the 37 treated with dextran (21% v 51%), as was the incidence of thrombi in the femoral or popliteal veins (2% v 16%). Objective measures of blood loss showed no difference between patients treated with warfarin or dextran, and excessive postoperative bleeding was infrequent and similar in both treatment groups. This study demonstrates that two-step warfarin therapy provides highly effective prophylaxis of postoperative venous thrombosis after elective hip or knee prosthetic surgery without excessive risk of perioperative bleeding.
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PMID:Two-step warfarin therapy. Prevention of postoperative venous thrombosis without excessive bleeding. 618 93

In a prospective study of the frequency of deep vein thrombosis (DVT) in 45 patients subjected to major abdominal surgery, 17 patients showed signs of DVT as assessed by the 125I-fibrinogen test. In 15 of the patients the DVT was diagnosed during the first four postoperative days. Blood samples were taken pre- and postoperatively and analysed for fibrinogen, prothrombin complex, APTT, platelet-count, plasminogen, alpha 2-antiplasmin, fibrin(ogen) degradation products, and plasmin-alpha 2-antiplasmin complex (PAP). The latter was used in order to reflect the fibrinolytic activity. Preoperatively, and postoperatively on day 3, the levels of PAP were significantly higher in patients without postoperative DVT. The data suggests that patients subjected to major abdominal surgery, who have enhanced fibrinolytic activity preoperatively, have a lesser tendency to develop postoperative DVT. Patients with postoperative DVT may have decreased fibrinolytic ability. From the data of the other parameters it is concluded that patients with DVT can have increased levels of FDP at the time of development of thrombosis.
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PMID:Fibrinolytic activity in plasma and deep vein thrombosis after major abdominal surgery. 622 99

In order to investigate whether a more intensive initial oral anticoagulation still would be safe and effective, we performed a prospective randomized study in patients with deep vein thrombosis. They received either the conventional regimen of oral anticoagulation ("low-dose") and heparin or a more intense oral anticoagulation ("high-dose") with a shorter period of heparin treatment. In the first part of the study 129 patients were randomized. The "low-dose" group reached a stable therapeutic prothrombin complex (PT)-level after 4.3 and the "high-dose" group after 3.3 days. Heparin was discontinued after 6.0 and 5.0 days respectively. There was no difference in significant hemorrhage between the groups, and no clinical signs of progression of the thrombosis. In the second part of the study another 40 patients were randomized, followed with coagulation factor II, VII, IX and X and with repeated venograms. A stable therapeutic PT-level was achieved after 4.4 ("low-dose") and 3.7 ("high-dose") days, and heparin was discontinued after 5.4 and 4.4 days respectively. There were no clinical hemorrhages, the activity of the coagulation factors had dropped to the same level in both groups at the time when heparin was discontinued and no thromboembolic complications occurred. Our oral anticoagulation regimen with heparin treatment for an average of 4.4-5 days seems safe and reduces in-patient costs.
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PMID:Intensive initial oral anticoagulation and shorter heparin treatment in deep vein thrombosis. 639 71


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