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Medline ® Abstracts for References 14-16

of 'Perioperative management of patients receiving anticoagulants'

14
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Management of anticoagulation before and after elective surgery.
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Kearon C, Hirsh J
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N Engl J Med. 1997;336(21):1506.
 
AD
McMaster University and Hamilton Civic Hospitals Research Centre, ON, Canada.
PMID
15
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Optimal duration of oral anticoagulant therapy: a randomized trial comparing four weeks with three months of warfarin in patients with proximal deep vein thrombosis.
AU
Levine MN, Hirsh J, Gent M, Turpie AG, Weitz J, Ginsberg J, Geerts W, LeClerc J, Neemeh J, Powers P
SO
Thromb Haemost. 1995;74(2):606.
 
The optimal duration of oral anticoagulant therapy for patients with acute proximal deep vein thrombosis (DVT) is uncertain. Based on the hypothesis that a normal impedance plethysmogram (IPG) following DVT defines a group of patients at low risk of recurrent venous thromboembolism (VTE), a trial was conducted to evaluate the efficacy of only four weeks of warfarin. Patients with venographically confirmed acute proximal DVT who had received four weeks of warfarin after initial heparin and whose four week IPG was normal were allocated to either continue warfarin (targeted International Normalized Ratio 2.0 to 3.0) for a further eight weeks or receive placebo. Patients with an abnormal four week IPG received warfarin for a further eight weeks. Based on clinical characteristics at the time of the qualifying thrombosis, all patients were classified as having either continuing or transient risk factors for recurrent VTE. During the eight weeks following randomization, nine (8.6%) of the 105 placebo patients developed recurrent VTE compared to one (0.9%) of the 109 warfarin patients, P = 0.009. Over the entire 11 months of follow-up, 12 placebo patients developed recurrence compared to seven warfarin patients, P = 0.3. Nineteen of the 192 patients with an abnormal four week IPG experienced recurrence during the nine months after discontinuing warfarin. In the 301 patients who received three months of warfarin in the randomized trial or in the cohort study, all 26 recurrent events were in the 212 patients with continuing risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)
AD
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
PMID
16
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Optimum duration of anticoagulation for deep-vein thrombosis and pulmonary embolism. Research Committee of the British Thoracic Society.
AU
SO
Lancet. 1992;340(8824):873.
 
The optimum duration of anticoagulation therapy for deep-vein thrombosis (DVT) and pulmonary embolism (PE) is not clear. We have carried out a multicentre comparison of 4 weeks' and 3 months' anticoagulation in patients admitted to hospital with acute DVT, PE, or both. Of 712 patients enrolled, 358 were assigned 4 weeks' treatment and 354 3 months'. Objective confirmation of the diagnosis was obtained in 71%. PE caused or contributed to death in 7 patients (3 treated for 4 weeks, 4 for 3 months). Adverse effects were uncommon, although 1 patient (4-week group) died of haemorrhage. The numbers of patients whose thromboembolism failed to resolve on treatment was lower in the 3-month group than in the 4-week group (13 [3.7%]vs 24 [6.7%], p = 0.10) as was the number who had recurrences (14 [4.0%]vs 28 [7.8%], p = 0.04). Among patients with postoperative DVT or PE the rate of treatment failure and recurrence was low (2.6%) and there was little difference between the treatment groups. By contrast, among medical patients the rate was 12.8%, with a clear difference in favour of 3 months' treatment. If venous thromboembolism arises after surgery, 4 weeks of anticoagulation should be adequate. In other settings, patients with new DVT, PE, or both, who do not have a persisting underlying cause or risk factor should receive anticoagulants for 3 months.
AD
PMID