Enoxaparin for the prevention of venous thromboembolism associated with central vein catheter: a double-blind, placebo-controlled, randomized study in cancer patients. Prevention of central venous line-related thrombosis by continuous infusion of low-dose unfractionated heparin, in patients with haemato-oncological disease. A randomized controlled trial. Dalteparin for prevention of catheter-related complications in cancer patients with central venous catheters: final results of a double-blind, placebo-controlled phase III trial. Low-molecular-weight heparin (nadroparin) and very low doses of warfarin in the prevention of upper extremity thrombosis in cancer patients with indwelling long-term central venous catheters: a pilot randomized trial. Upper extremity deep venous thrombosis in cancer patients with venous access devices--prophylaxis with a low molecular weight heparin (Fragmin). Very low doses of warfarin can prevent thrombosis in central venous catheters. A randomized prospective trial. An open-label randomized controlled trial of low molecular weight heparin for the prevention of central venous line-related thrombotic complications in children: the PROTEKT trial. Early and short-term acenocumarine or dalteparin for the prevention of central vein catheter-related thrombosis in cancer patients: a randomized controlled study based on serial venographies. Minidose (1 mg) warfarin as prophylaxis for central vein catheter thrombosis. Prevention of catheter-related venous thrombosis with nadroparin in patients receiving chemotherapy for hematologic malignancies: a randomized, placebo-controlled study. Low-dose warfarin for the prevention of central line-associated thromboses in children with malignancies--a randomized, controlled study.
The extent of venous thromboembolism (VTE) associated with central vein catheters (CVC) in cancer patients remains unclear. The aim of this study was to evaluate the efficacy and safety of the low molecular weight heparin, enoxaparin, in the prevention of VTE.
                In a multicenter, double-blind study, consecutive cancer patients scheduled for CVC insertion were randomly assigned to receive either subcutaneous enoxaparin 40 mg once a day or placebo. Treatment was started 2 hours before CVC insertion and continued for 6 weeks. The primary end points of the study were deep vein thrombosis (DVT), confirmed by venography of the CVC limb performed 6 weeks after randomization, or clinically overt pulmonary embolism, confirmed by objective testing during the study drug administration. Patients were assessed for bleeding complications.
                Three hundred eighty-five patients were randomized, of which 321 (83.4%) underwent venography. A venography was adequate for adjudication in 155 patients in each treatment group. A DVT was observed in 22 patients (14.1%) treated with enoxaparin and in 28 patients (18.0%) treated with placebo, corresponding to a relative risk of 0.78 (95% CI, 0.47 to 1.31). No major bleeding occurred. Five patients (2.6%) in the enoxaparin group and two patients (1.0%) in the placebo group died during the treatment period.
                In this study, no difference in the rate of CVC-related VTE was detected between patients receiving enoxaparin and patients receiving placebo. The dose of enoxaparin used in this study proved to be safe. Clinical trials evaluating higher enoxaparin doses could optimize the efficacy of this agent for this indication. We have conducted a prospective randomized controlled trial to evaluate the role of low-dose unfractionated heparin prophylaxis in preventing central venous line-related thrombosis in patients with haemato-oncological disease. Patients were randomly assigned to receive either prophylactic intravenous unfractionated heparin (continuous infusion of 100 IU/kg/daily) or 50 ml/daily of normal saline solution as a continuous infusion. CVLs were externalized, non tunneled, double lumen catheters. All CVLs were placed percutaneously by the same physician in the subclavian vein. Upper limb veins were systematically examined by ultrasonography just before, or <24 hours after, catheter removal, and in case of clinical signs of thrombosis. One hundred and twenty-eight CVLs were inserted. Catheter-related thrombosis occurred in 1.5% of the catheters inserted in patients of the heparin group, and in 12.6% in the control group (p = 0.03). No other risk factors were found for the development of catheter-related thrombosis. Two and three patients experienced severe bleeding in the heparin group, and in the control group, respectively (p = 0.18). There were no other side-effects clearly ascribable to the use of unfractionated heparin. This is the first prospective, randomized study, which shows that low-dose of unfractionated heparin is safe and effective to prevent catheter-related thrombosis in patients with haemato-oncological disease. Cancer patients receiving chemotherapy experience thromboembolic complications associated with the use of long-term indwelling central venous catheters (CVCs). This prospective, double-blind, placebo-controlled, multicenter study evaluated whether prophylactic treatment with a low molecular weight heparin could prevent clinically relevant catheter-related thrombosis.
                Patients with cancer undergoing chemotherapy for at least 12 weeks (n=439) were randomly assigned, in a 2:1 ratio, to receive either dalteparin (5000 IU) or placebo, by subcutaneous injection, once daily for 16 weeks. Patients underwent upper extremity evaluation with either venography or ultrasound at the time of a suspected catheter-related complication (CRC) or upon completion of study medication. The primary end point, as determined by a blinded adjudication committee, was the occurrence of a CRC, defined as the first occurrence of any one of the following: clinically relevant catheter-related thrombosis that was symptomatic or that required anticoagulant or fibrinolytic therapy; catheter-related clinically relevant pulmonary embolism; or catheter obstruction requiring catheter removal.
                There was no significant difference in the frequency of CRCs between the dalteparin arm (3.7%) and the placebo arm (3.4%; P=0.88), corresponding to a relative risk of 1.0883 (95% confidence interval 0.37-3.19). No difference in the time to CRC was observed between the two arms (P=0.83). There was no significant difference between the dalteparin and placebo groups in terms of major bleeding (1 versus 0) or overall safety.
                Dalteparin prophylaxis did not reduce the frequency of thromboembolic complications after CVC implantation in cancer patients. Dalteparin was demonstrated to be safe over 16 weeks of treatment in these patients. Upper extremity thrombosis is a major complication of central venous catheters implanted for chemotherapy in cancer patients. Vitamin K antagonists and low-molecular-weight heparins have been recommended in this setting, but their relative benefit-to-risk ratios have never been compared.
                A prospective, randomized, open, parallel-group, multicenter trial was performed comparing the antithrombotic efficacy and safety of warfarin and the low-molecular-weight heparin, nadroparin, in cancer patients who had undergone central venous catheter implantation. Warfarin was given orally at a fixed daily dose of 1 mg and nadroparin was injected subcutaneously at a fixed daily dose of 2,850 IU for 90 days, or until venographically-confirmed thrombosis occurred. The primary efficacy outcome was the occurrence of upper extremity thrombosis confirmed by venography performed 90 days after insertion of the catheter, or earlier if symptoms of thrombosis had appeared. Safety end-points were bleeding and thrombocytopenia.
                Fifty-nine patients were included in the study. A total of 21 and 24 patients in the nadroparin and warfarin groups, respectively, were evaluable for primary efficacy. Six out of the 21 patients in the nadroparin group (28.6%) and 4 out of the 24 patients in the warfarin group (16.7%) had venographically-documented upper extremity thrombosis at day 90 (p=0.48). Safety was satisfactory and similar with both treatments.
                Warfarin at a fixed, very low dose and nadroparin at a fixed, prophylactic dose had comparable benefit-to-risk ratios in the prevention of thrombosis associated with central venous catheters in cancer patients. Central venous access devices are often essential for the administration of chemotherapy to patients with malignancy, but its use has been associated with a number of complications, mainly thrombosis. The true incidence of upper extremity deep vein thrombosis (DVT) in this setting is difficult to estimate since there are very few studies in which DVT diagnosis was based on objective tests, but its sequelae include septic thrombophlebitis, loss of central venous access and pulmonary embolism. We performed an open, prospective study in which all cancer patients who underwent placement of a long-term Port-a-Cath (Pharmacia Deltec Inc) subclavian venous catheter were randomized to receive or not 2500 IU sc of Fragmin once daily 90 days. Venography was routinely performed 90 days after catheter insertion, or sooner if DVT symptoms had appeared. Our aims were: 1) to investigate the effectiveness of low doses of Fragmin in preventing catheter-related DVT; and 2) to try to confirm if patients with high platelet counts are at a higher risk to develop subclavian DVT, as previously suggested. On the recommendation of the Ethics Committee, patient recruitment was terminated earlier than planned: DVT developed in 1/16 patients (6%) taking Fragmin and 8/13 patients (62%) without prophylaxis (Relative Risk 6.75; 95% CI: 1.05-43.58; p = 0.002, Fisher exact test). No bleeding complications had developed. As for prediction of DVT, there was a tendency towards a higher platelet count in those patients who subsequently developed DVT, but differences failed to reach any statistical significance (286 +/- 145 vs 207 +/- 81 x 10(9)/1; p = 0.067). According to our experience, Fragmin at the dosage used proved to be both effective and safe in these patients. To determine whether very low doses of warfarin are useful in thrombosis prophylaxis in patients with central venous catheters.
                Patients at risk for thrombosis associated with chronic indwelling central venous catheters were prospectively and randomly assigned to receive or not to receive 1 mg of warfarin, beginning 3 days before catheter insertion and continuing for 90 days. Subclavian, innominate, and superior vena cava venograms were done at onset of thrombosis symptoms or after 90 days in the study.
                One hundred twenty-one patients entered the study, and 82 patients completed the study. Of 42 patients completing the study while receiving warfarin, 4 had venogram-proven thrombosis. All 4 had symptoms from thrombosis. Of 40 patients completing the study while not receiving warfarin, 15 had venogram-proven thrombosis, and 10 had symptoms from thrombosis (P less than 0.001). There were no measurable changes in the coagulation values assayed due to this warfarin dose, except in occasional patients who had become anorectic because of their disease or chemotherapy.
                Very low doses of warfarin can protect against thrombosis without inducing a hemorrhagic state. This approach may be applicable to other groups of patients. Central venous lines (CVLs) are major risk factors for venous thromboembolism (VTE) in children. The objective of PROTEKT was to determine if a low molecular weight heparin (reviparin-sodium) safely prevents CVL-related VTE.
                This multi-center, open-label study, with blinded central outcome adjudication, randomized patients with new CVLs to twice-daily reviparin-sodium or standard care. The efficacy outcome was based on an exit venogram at Day 30 (+14 days), or earlier in case of CVL removal, or confirmed symptomatic VTE. The safety outcomes were major bleeding and death. Due to slow and restricted patient accrual, PROTEKT was closed prematurely.
                With reviparin-sodium, 14.1% (11:78) of patients had VTE compared to 12.5% (10:80) of control patients (odds ratio=1.15; 95% confidence interval 0.42, 3.23); 2P=0.82). One patient had a major bleed and there were two deaths, all three events occurring in the standard care group.
                The use of reviparin-sodium for short-term prophylaxis of CVL-related VTE in children was safe but its efficacy remains unclear. Although underpowered, PROTEKT provided valuable information on event rates and predictors of CVL-related VTE. We evaluated efficacy and safety of early and short-term prophylaxis with acenocumarine or dalteparin in the prevention of non-occlusive or occlusive central vein catheter-related thrombosis (CVCrT).
                Consecutive cancer patients scheduled for chemotherapy randomly received: acenocumarine 1 mg/day for 3 days before and 8 days after central vein catheter (CVC) insertion; dalteparin 5000 IU 2 h before and daily for 8 days after CVC insertion; no anticoagulant treatment (NT). All patients underwent venography on days 8 and 30, some of them on days 90, 150 and 210 after CVC.
                A total of 450 patients were randomized, 348 underwent at least two venography. Both acenocumarine and dalteparin reduced venography-detected CVCrT rate [21.9% acenocumarine versus 52.6% NT, odds ratio (OR) 0.3, P < 0.01; 40% dalteparin versus 52.6% NT, OR 0.6, P = 0.05]. Acenocumarine was more effective than dalteparin (OR 0.4, P = 0.01). The rate of occlusive CVCrT was not different in the three groups (0.9% acenocumarine, 3.3% dalteparin, 1.8% NT; P = 0.40). Most CVCrTs (95.6%) were observed on day 8 after CVC insertion and were non-occlusive.
                In this study of early and short-term prophylaxis, acenocumarine was more effective than dalteparin on non-occlusive and asymptomatic CVCrT events. The first days following CVC insertion represent the highest risk for CVCrT. Central vein catheters, which are used in the treatment of cancer patients, are prone to thrombotic complications of the catheter or adjacent vein. Previous studies suggest that 1 mg warfarin daily (minidose) can significantly reduce that risk.
                This, study aims to establish whether minidose warfarin could reduce catheter-related thrombosis in adult patients with haematological malignancies.
                Patients were randomly selected to receive warfarin or not. The end-points studied were: (i) occlusion by thrombus, (ii) removal of catheter for other reasons or (iii) 90 days free of thrombus.
                There was no significant difference in the incidence of catheter thrombosis or venous thrombosis and no significant variation in catheter survival between the study and control groups.
                This study found no benefit of the routine use of minidose warfarin for prophylaxis of central vein' catheter thrombosis in patients with haematological malignancies and therefore does not support the routine use of minidose warfarin for prophylaxis in such patients. Hemato-oncology patients treated with intensive chemotherapy usually require the placement of a central venous catheter (CVC). CVCs are frequently complicated by catheter-related central venous thrombosis (CVT), which has been associated with an increased risk of pulmonary embolism and catheter-related infection.
                To determine the efficacy and safety of thromboprophylaxis with s.c. low-molecular-weight heparin (nadroparin) administered once daily in a randomized placebo-controlled, double-blind trial in patients with hematologic malignancies.
                Consecutive patients with hematologic malignancies requiring intensive chemotherapy including autologous stem cell transplantation were eligible. The patients were randomized to receive nadroparin 2850 antifactor Xa units once daily or placebo s.c. for 3 weeks. Venography was performed on day 21 after CVC insertion. Secondary outcomes were bleeding and catheter-related infection.
                In total, 113 patients were randomized to nadroparin or placebo, and 87 patients (77%) underwent venography. In total, 11 venographically proven catheter-related CVTs were diagnosed. The frequency of catheter-related CVT was not significantly different between study groups, namely four catheter-related CVTs in the placebo group [9%; 95% CI: 0.002-0.16] vs. seven catheter-related CVTs in the nadroparin group (17%; 95% CI: 0.06-0.28). In addition, no difference in the incidence of catheter-related infection or bleeding was observed between the groups.
                This study showed that the actual risk for catheter-related CVT in patients with hematologic malignancies is lower than suggested in earlier studies in cancer patients. Although prophylactic administration of nadroparin appeared to be safe in this group of patients with a high risk of bleeding, it cannot be recommended for the prevention of catheter-related CVT or catheter-related infection in patients with hematologic malignancies. Central venous lines (CVLs) are essential in the care of children with malignancies, but are associated with venous thromboembolism (VTE) and infections. Effective and safe prophylactic approaches are deficient.
                To perform a study of adjusted low-dose warfarin for the prevention of CVL-related VTE in children with malignancies.
                Children with newly diagnosed cancer, a CVL in a jugular vein and an expected treatment period of over 6 mo were eligible for the study. Participants were randomized to low-dose warfarin, with intended international normalized ratio (INR) 1.3-1.9, or to a control group. Primary outcome was VTE in a jugular vein diagnosed by ultrasonography at 1, 3 and 6 mo after inclusion. Secondary outcome was CVL-related infections, mainly measured as days on antibiotics or positive blood cultures.
                The study enrolled 73 children, and 62 completed it fully. Asymptomatic CVL-related VTE was frequent (42%), but often transient. Regardless of severity, timing and duration, CVL-related VTE was equally frequent among children on warfarin as compared to controls (p=0.44). Low-dose warfarin (p=0.59) or jugular CVL-related VTE (p=0.91) did not have any impact on days on antibiotics, but we observed a tendency towards an association between CVL-related VTE and positive blood cultures (p=0.15).
                Our randomized study of low-dose oral anticoagulation for the prevention of CVL-related asymptomatic VTE in children with cancer did not show any benefit of warfarin adjusted to maintain INR between 1.3 and 1.9.
We found no statistically significant effect of heparin or VKA on the outcomes of interest. However, the findings did not rule out clinically important benefits and harms. Patients with cancer with CVCs considering anticoagulation should balance the possible benefit of reduced thromboembolic complications with the possible harms and burden of anticoagulants.