Secondary prevention of venous thromboembolism with the oral direct thrombin inhibitor ximelagatran. Dabigatran versus warfarin in the treatment of acute venous thromboembolism. Comparison of low-molecular-weight heparin and warfarin for the secondary prevention of venous thromboembolism in patients with cancer: a randomized controlled study. Secondary prevention of venous thromboembolic events in patients with active cancer: enoxaparin alone versus initial enoxaparin followed by warfarin for a 180-day period. Low-molecular-weight heparin versus a coumarin for the prevention of recurrent venous thromboembolism in patients with cancer. Long-term low-molecular-weight heparin versus usual care in proximal-vein thrombosis patients with cancer. Low molecular weight heparin versus oral anticoagulants in the long-term treatment of deep venous thrombosis.
For many patients with venous thromboembolism, secondary prevention with vitamin K antagonists is not extended beyond six months, since the risk of recurrence may be outweighed by the risk of major bleeding.
                In a double-blind, multicenter trial, we randomly assigned 1233 patients with venous thromboembolism who had undergone six months of anticoagulant therapy to extended secondary prevention with the oral direct thrombin inhibitor ximelagatran (24 mg) or placebo, taken twice daily, for 18 months without monitoring of coagulation. At base line, bilateral ultrasonography of the legs and perfusion lung scanning were performed.
                Data from 612 patients in the ximelagatran group and 611 in the placebo group were analyzed. The occurrence of the primary end point, symptomatic recurrent venous thromboembolism, was confirmed in 12 patients assigned to ximelagatran and 71 patients assigned to placebo (hazard ratio, 0.16; 95 percent confidence interval, 0.09 to 0.30; P<0.001). Death from any cause occurred in 6 patients in the ximelagatran group and 7 patients in the placebo group, and bleeding occurred in 134 patients and 111 patients, respectively (hazard ratio, 1.19; 95 percent confidence interval, 0.93 to 1.53; P=0.17). The incidence of major hemorrhage was low (six events in the ximelagatran group and five in the placebo group), and none of these hemorrhages were fatal. The cumulative risk of a transient elevation of the alanine aminotransferase level to more than three times the upper limit of normal was 6.4 percent in the ximelagatran group, as compared with 1.2 percent in the placebo group (P<0.001).
                Oral ximelagatran was superior to placebo for the extended prevention of venous thromboembolism. There was no significant increase in the frequency of bleeding complications, but there was an increase in the number of patients with a transient elevation in the alanine aminotransferase level.
                Copyright 2003 Massachusetts Medical Society The direct oral thrombin inhibitor dabigatran has a predictable anticoagulant effect and may be an alternative therapy to warfarin for patients who have acute venous thromboembolism.
                In a randomized, double-blind, noninferiority trial involving patients with acute venous thromboembolism who were initially given parenteral anticoagulation therapy for a median of 9 days (interquartile range, 8 to 11), we compared oral dabigatran, administered at a dose of 150 mg twice daily, with warfarin that was dose-adjusted to achieve an international normalized ratio of 2.0 to 3.0. The primary outcome was the 6-month incidence of recurrent symptomatic, objectively confirmed venous thromboembolism and related deaths. Safety end points included bleeding events, acute coronary syndromes, other adverse events, and results of liver-function tests.
                A total of 30 of the 1274 patients randomly assigned to receive dabigatran (2.4%), as compared with 27 of the 1265 patients randomly assigned to warfarin (2.1%), had recurrent venous thromboembolism; the difference in risk was 0.4 percentage points (95% confidence interval [CI], -0.8 to 1.5; P<0.001 for the prespecified noninferiority margin). The hazard ratio with dabigatran was 1.10 (95% CI, 0.65 to 1.84). Major bleeding episodes occurred in 20 patients assigned to dabigatran (1.6%) and in 24 patients assigned to warfarin (1.9%) (hazard ratio with dabigatran, 0.82; 95% CI, 0.45 to 1.48), and episodes of any bleeding were observed in 205 patients assigned to dabigatran (16.1%) and 277 patients assigned to warfarin (21.9%; hazard ratio with dabigatran, 0.71; 95% CI, 0.59 to 0.85). The numbers of deaths, acute coronary syndromes, and abnormal liver-function tests were similar in the two groups. Adverse events leading to discontinuation of the study drug occurred in 9.0% of patients assigned to dabigatran and in 6.8% of patients assigned to warfarin (P=0.05).
                For the treatment of acute venous thromboembolism, a fixed dose of dabigatran is as effective as warfarin, has a safety profile that is similar to that of warfarin, and does not require laboratory monitoring. (ClinicalTrials.gov number, NCT00291330.)
                Copyright 2009 Massachusetts Medical Society. The use of warfarin sodium for treating venous thromboembolism in patients with cancer is associated with a significant risk of recurrence and bleeding. The use of low-molecular-weight heparin sodium for secondary prevention of venous thromboembolism in cancer patients may reduce the complication rate.
                To determine whether a fixed dose of subcutaneous low-molecular-weight heparin is superior to oral warfarin for the secondary prophylaxis of venous thromboembolism in patients with cancer and venous thromboembolism.
                In a randomized, open-label multicenter trial performed between April 1995 and March 1999, we compared subcutaneous enoxaparin sodium (1.5 mg/kg once a day) with warfarin given for 3 months in 146 patients with venous thromboembolism and cancer.
                A combined outcome event defined as major bleeding or recurrent venous thromboembolism within 3 months.
                Of the 71 evaluable patients assigned to receive warfarin, 15 (21.1%; 95% confidence interval [CI], 12.3%-32.4%) experienced one major outcome event compared with 7 (10.5%) of the 67 evaluable patients assigned to receive enoxaparin (95% CI, 4.3%-20.3%; P =.09). There were 6 deaths owing to hemorrhage in the warfarin group compared with none in the enoxaparin group. In the warfarin group, 17 patients (22.7%) died (95% CI, 13.8%-33.8%) compared with 8 (11.3%) in the enoxaparin group (95% CI, 5.0%-21.0%; P =.07). No difference was observed regarding the progression of the underlying cancer or cancer-related death.
                These results confirm that warfarin is associated with a high bleeding rate in patients with venous thromboembolism and cancer. Prolonged treatment with low-molecular-weight heparin may be as effective as oral anticoagulants and may be safer in these cancer patients. This study evaluated enoxaparin alone versus initial enoxaparin followed by warfarin in secondary prevention of venous thromboembolic events in adults with active malignancy. Cancer patients (n = 122) with acute symptomatic venous thromboembolic events were randomly allocated to receive subcutaneous enoxaparin 1.0 mg/kg every 12 hours for 5 days, followed by 1.0 mg/kg daily (group 1a) or 1.5 mg/kg daily (group 1b) for 175 days, or subcutaneous enoxaparin 1.0 mg/kg every 12 hours for at least 5 days and until a stable international normalized ratio of 2 to 3 was achieved on oral warfarin begun on day 2 and continued to day 180 (group 2). There were no significant differences in major and minor bleeding rates between treatment groups. No bleeding events were intracranial or fatal. Enoxaparin treatment was feasible, generally well tolerated, and effective for a 180-day period in the secondary prevention of venous thromboembolic events in patients with active malignancy. Patients with cancer have a substantial risk of recurrent thrombosis despite the use of oral anticoagulant therapy. We compared the efficacy of a low-molecular-weight heparin with that of an oral anticoagulant agent in preventing recurrent thrombosis in patients with cancer.
                Patients with cancer who had acute, symptomatic proximal deep-vein thrombosis, pulmonary embolism, or both were randomly assigned to receive low-molecular-weight heparin (dalteparin) at a dose of 200 IU per kilogram of body weight subcutaneously once daily for five to seven days and a coumarin derivative for six months (target international normalized ratio, 2.5) or dalteparin alone for six months (200 IU per kilogram once daily for one month, followed by a daily dose of approximately 150 IU per kilogram for five months).
                During the six-month study period, 27 of 336 patients in the dalteparin group had recurrent venous thromboembolism, as compared with 53 of 336 patients in the oral-anticoagulant group (hazard ratio, 0.48; P=0.002). The probability of recurrent thromboembolism at six months was 17 percent in the oral-anticoagulant group and 9 percent in the dalteparin group. No significant difference between the dalteparin group and the oral-anticoagulant group was detected in the rate of major bleeding (6 percent and 4 percent, respectively) or any bleeding (14 percent and 19 percent, respectively). The mortality rate at six months was 39 percent in the dalteparin group and 41 percent in the oral-anticoagulant group.
                In patients with cancer and acute venous thromboembolism, dalteparin was more effective than an oral anticoagulant in reducing the risk of recurrent thromboembolism without increasing the risk of bleeding.
                Copyright 2003 Massachusetts Medical Society A substantial clinical need exists for an alternative to vitamin K antagonists for treating deep-vein thrombosis in cancer patients who are at high risk of both recurrent venous thromboembolism and bleeding. Low-molecular-weight heparin, body-weight adjusted, avoids anticoagulant monitoring and has been shown to be more effective than vitamin-K-antagonist therapy.
                Subjects were patients with cancer and acute symptomatic proximal-vein thrombosis. We performed a multi-centre randomized, open-label clinical trial using objective outcome measures comparing long-term therapeutic tinzaparin subcutaneously once daily with usual-care long-term vitamin-K-antagonist therapy for 3 months. Outcomes were assessed at 3 and 12 months.
                Of 200 patients, 100 received tinzaparin and 100 received usual care. At 12 months, the usual-care group had an excess of recurrent venous thromboembolism; 16 of 100 (16%) versus 7 of 100 (7%) receiving low-molecular-weight heparin (P=.044; risk ratio=.44; absolute difference -9.0; 95% confidence interval [CI], -21.7 to -0.7). Bleeding, largely minor, occurred in 27 patients (27%) receiving tinzaparin and 24 patients (24%) receiving usual care (absolute difference -3.0; 95% CI, -9.1 to 15.1). In patients without additional risk factors for bleeding at the time of randomization, major bleeding occurred in 0 of 51 patients (0%) receiving tinzaparin and 1 of 48 patients (2.1%) receiving usual care. Mortality at 1 year was high, reflecting the severity of the cancers; 47% in each group died.
                Our findings confirm the limited but benchmark data in the literature that long-term low-molecular-weight heparin is more effective than vitamin-K-antagonist therapy for preventing recurrent venous thromboembolism in patients with cancer and proximal venous thrombosis. The purpose of this study was to evaluate whether low molecular weight heparin (LMWH) could be equal or more effective than conventional oral anticoagulants (OAs) in the long-term treatment of deep venous thrombosis (DVT).
                One hundred fifty-eight patients with symptomatic DVT of the lower limbs confirmed by means of duplex ultrasound scan were randomized to receive 3 to 6 months' treatment with nadroparine calcium or acenocoumarol. Quantitative and qualitative duplex scan scoring systems were used to study the evolution of thrombosis in both groups at 1, 3, 6, and 12 months.
                During the 12-month surveillance period, two (2.5%) of the 81 patients who received LMWH and seven (9%) of the 77 patients who received OAs had recurrence of venous thrombosis (not significant). In the LMWH group no cases of major bleeding were found, and four cases (5.2%) occurred in the OA group (not significant). The mortality rate was nine (11.1%) in the LMWH group and 7.8% in the OA group (not significant). The quantitative mean duplex scan score decreased in both groups during the follow-up and had statistical significance after long-term LMWH treatment on iliofemoral DVT (1, 3, 6, and 12 months), femoropopliteal DVT (1-3 months), and infrapopliteal DVT (first month). Duplex scan evaluation showed that the rate of venous recanalization significantly increased in the common femoral vein at 6 and at 12 months and during each point of follow-up in the superficial and popliteal veins in the LMWH group. Reflux was significantly less frequent in communicating veins after LMWH treatment (17.9% vs 32.2% in the OA group). The reflux rates in the superficial (22.4% in the LMWH group, 30.6% in OA group) and deep (13.4% vs 17.7%) venous system showed no significant differences between groups.
                The unmonitored subcutaneous administration of nadroparine in fixed daily doses was more effective than oral acenocoumarol with laboratory control adjustment in achieving recanalization of leg thrombi. With nadroparine, there was less late valvular communicating vein insufficiency, and it was at least as efficacious and safe as oral anticoagulants after long-term administration. These results suggest that LMWHs may therefore represent a real therapeutic advance in the long-term management of DVT.
For the long-term treatment of VTE in patients with cancer, LMWH compared to VKA reduces venous thromboembolic events but not death. The decision for a patient with cancer and VTE to start long-term LMWH versus oral anticoagulation should balance the benefits and downsides and integrate the patient's values and preferences for the important outcomes and alternative management strategies.