Is antithrombotic prophylaxis required in cancer patients with central venous catheters? No

Risk factors for upper limb deep vein thrombosis associated with the use of central vein catheter in cancer patients

Deep vein thrombosis of upper limb is a common complication of CVC in patients with cancer. In these patients the risk factors for CVC-related thrombosis are not completely defined. The purpose of this study was to identify the risk factors for CVC-related thrombosis in patients included in a randomized, double-blind, placebo-controlled study aimed at assessing the efficacy and safety of enoxaparin for the prophylaxis of CVC-related thrombosis. CVC-related thrombosis was screened by mandatory venography after 6 weeks of study treatment. A number of patient baseline characteristics were assessed as potential risk factors for CVC-related deep vein thrombosis. Crude associations between risk factors and clinical outcomes were assessed by chi(2) test or Fisher's exact test. Multiple logistic regression analysis was used to identify independent risk factors. A CVC-related thrombosis was found in 50 out of 310 patients (16.1%). At multiple logistic regression analysis, CVC tip misplaced in the upper half of superior vena cava (OR 4.05, 95%CI 1.64-10.02), left-sided CVC insertion (OR 2.29, 95%CI 1.01-5.51) and chest radiotherapy (OR 7.01, 95%CI 1.42-34.66) were independent risk factors for thrombosis. In addition to these risk factors, the presence of distant metastases (OR 9.36, 95%CI 1.53-57.05) increased the risk of thrombosis in patients who received placebo. An inadequate position of the CVC tip, left-sided CVC insertion and chest radiotherapy are independent risk factors for CVC-related thrombosis in cancer patients. Patients with distant metastases have an increased risk for thrombosis in absence of antithrombotic prophylaxis.

Prevention of central venous catheter-associated thrombosis: a meta-analysis

PURPOSE

Anticoagulant prophylaxis in patients with central venous catheters is controversial. We performed a meta-analysis of randomized controlled trials of anticoagulant prophylaxis in patients with central venous catheters.

METHODS

MEDLINE and EMBASE were searched up to May 2006, supplemented by manual searches of conference proceedings and bibliographies.

RESULTS

Fifteen trials were included. Unfractionated heparin infusion, oral fixed low-dose vitamin K antagonist, and subcutaneous low-molecular-weight heparin were evaluated. For all catheter-associated deep vein thrombosis (symptomatic and asymptomatic combined), the summary relative risks ranged from 0.31 to 0.73 (all achieved statistical significance). For symptomatic deep vein thrombosis, the summary relative risks ranged from 0.28 to 0.72, but did not achieve statistical significance for any individual regimen.

CONCLUSION

Anticoagulant prophylaxis is effective for preventing all catheter-associated deep vein thrombosis in patients with central venous catheters. The effectiveness for preventing symptomatic venous thromboembolism, including pulmonary embolism, remains uncertain.

Thromboprophylaxis of central venous lines in children with cancer: the first steps taken on the long road ahead

Approximately one third of children with malignancy and central venous lines develop catheter-related thrombosis, with the reported sequelae including death, pulmonary embolism, chylothoraces, superior vena cava syndrome and post-thrombotic syndrome. These complications prompt the design and completion of randomized, controlled trials to determine a safe and efficacious therapy to prevent these thromboses. The authors Ruud et al. have presented a well-designed, randomized, controlled trial which demonstrates the lack of utility of using low-dose warfarin to prevent catheter-related thrombosis in children with central lines and acute lymphoblastic leukaemia. The difficulties with warfarin in children are again demonstrated in this study.

CONCLUSION

Further studies are warranted using other thromboprophylactic agents with less or no monitoring and fewer drug interactions, including the newer anticoagulant agents such as direct thrombin inhibitors.

Management of thrombosis in cancer: primary prevention and secondary prophylaxis

Although traditional anticoagulant regimens are highly effective and safe in most patients with venous thromboembolism (VTE), the aggressive natural history of VTE and the high risk of serious bleeding in cancer patients can complicate the management of VTE. In addition, because few clinical trials have focused on the prevention and treatment of VTE in this unique patient population, many clinical questions regarding the care of cancer patients with VTE remain unanswered. Currently, low-molecular-weight heparins and oral vitamin K antagonists are the most commonly used agents for the primary and secondary prophylaxis of VTE in patients with or without cancer, but their use is associated with pharmacological and practical limitations. This review will provide an up-to-date summary of the clinical trials that have addressed the management of VTE in patients with cancer. A brief discussion of the potential application of novel anticoagulants in these clinical settings is also included.