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

Heparin versus 0.9% sodium chloride locking for prevention of occlusion in central venous catheters in adults

BACKGROUND

Intermittent locking of central venous catheters (CVCs) is undertaken to help maintain their patency and performance. There are systematic variations in care: some practitioners use heparin (at different concentrations), whilst others use 0.9% sodium chloride (normal saline). This review looks at the effectiveness and safety of intermittent locking with heparin compared to normal saline, to see if the evidence establishes whether one is better than the other. This is an update of an earlier Cochrane Review.

OBJECTIVES

To evaluate the benefits and harms of intermittent locking of CVCs with heparin versus normal saline in adults to prevent occlusion.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 20 October 2021.

SELECTION CRITERIA

We included randomised controlled trials in adults ≥ 18 years of age with a CVC that compared intermittent locking with heparin at any concentration versus normal saline. We excluded studies on infants and children from this review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were occlusion of CVCs and duration of catheter patency. Our secondary outcomes were CVC-related bloodstream infections and CVC-related colonisation, mortality, haemorrhage, heparin-induced thrombocytopaenia, CVC-related thrombosis, number of additional CVC insertions, abnormality of coagulation profile and allergic reactions to heparin. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified one new RCT with 30 participants for this update. We included a total of 12 RCTs with 2422 participants. Data for meta-analysis were available from all RCTs. We noted differences in methods used by the included studies and variation in heparin concentrations (10 to 5000 IU/mL), time to follow-up (1 to 251.8 days), and the unit of analysis used (participant, catheter, line access). Five studies included ICU (intensive care unit) patients, two studies included oncology patients, and the remaining studies included miscellaneous patients (chronic kidney disease, haemodialysis, home care patients, etc.). Primary outcomes Overall, combined results may show fewer occlusions with heparin compared to normal saline but this is uncertain (risk ratio (RR) 0.70, 95% confidence interval (CI) 0.51 to 0.95; 10 studies; 1672 participants; low-certainty evidence). We pooled studies that used participant or catheter as the unit of analysis. We carried out subgroup analysis by unit of analysis. No clear differences were detected after testing for subgroup differences (P = 0.23). We found no clear evidence of a difference in the duration of catheter patency with heparin compared to normal saline (mean difference (MD) 0.44 days, 95% CI -0.10 to 0.99; 6 studies; 1788 participants; low-certainty evidence). Secondary outcomes We found no clear evidence of a difference in the following outcomes: CVC-related bloodstream infections (RR 0.66, 95% CI 0.08 to 5.80; 3 studies; 1127 participants; very low-certainty evidence); mortality (RR 0.76, 95% CI 0.44 to 1.31; 3 studies; 1100 participants; very low-certainty evidence); haemorrhage (RR 1.54, 95% CI 0.41 to 5.74; 3 studies; 1197 participants; very low-certainty evidence); or heparin-induced thrombocytopaenia (RR 0.21, 95% CI 0.01 to 4.27; 3 studies; 443 participants; very low-certainty evidence). The main reasons for downgrading the certainty of evidence for the primary and secondary outcomes were unclear allocation concealment, suspicion of publication bias, imprecision and inconsistency.

AUTHORS' CONCLUSIONS

Given the low-certainty evidence, we are uncertain whether intermittent locking with heparin results in fewer central venous catheter occlusions than intermittent locking with normal saline in adults. Low-certainty evidence suggests that heparin may have little or no effect on catheter patency duration. Although we found no evidence of differences in safety (CVC-related bloodstream infections, mortality, or haemorrhage), the combined studies were not powered to detect rare adverse events such as heparin-induced thrombocytopaenia. Further research conducted over longer periods would reduce the current uncertainties.

Venous thromboembolism associated with central venous catheters in patients with cancer: From pathophysiology to thromboprophylaxis, areas for future studies

Symptomatic catheter related thrombosis (CRT) occurs in 4%-8% of cancer patients. The mean incidence of CRT, detected either by echography or Doppler ranges between 12 and 14% with a high negative predictive value of about 95%, allowing the subsequent occurrence of CRT (symptomatic and asymptomatic) to be safely excluded. Despite its frequency and its medico-economic consequences, no thromboprophylaxis has been validated to date. In most patients, CRT occurs immediately after catheter insertion, most often within the first week and almost all within the first month after insertion. Meta analyses show a reduction of asymptomatic and symptomatic CRT incidence by about 55%-60% using either vitamin K antagonists or low molecular weight heparins without an increased risk of major bleeding. This pharmacological prophylaxis is only effective when started before the central venous catheter insertion at prophylactic doses and thereafter continued at subtherapeutic doses. Since no population at high risk of CRT has been identified, this review focuses on pathophysiology, epidemiology and clinical supportive data that could lead to a new CRT prophylaxis strategy.

Primary Thromboprophylaxis in Patients with Malignancies: Daily Practice Recommendations by the Hemostasis Working Party of the German Society of Hematology and Medical Oncology (DGHO), the Society of Thrombosis and Hemostasis Research (GTH), and the Austrian Society of Hematology and Oncology (ÖGHO)

Patients with cancer, both hematologic and solid malignancies, are at increased risk for thrombosis and thromboembolism. In addition to general risk factors such as immobility and major surgery, shared by non-cancer patients, cancer patients are exposed to specific thrombotic risk factors. These include, among other factors, cancer-induced hypercoagulation, and chemotherapy-mediated endothelial dysfunction as well as tumor-cell-derived microparticles. After an episode of thrombosis in a cancer patient, secondary thromboprophylaxis to prevent recurrent thromboembolism has long been established and is typically continued as long as the cancer is active or actively treated. On the other hand, primary prophylaxis, even though firmly established in hospitalized cancer patients, has only recently been studied in ambulatory patients. This recent change is mostly due to the emergence of direct oral anticoagulants (DOACs). DOACs have a shorter half-life than vitamin K antagonists (VKA), and they overcome the need for parenteral application, the latter of which is associated with low-molecular-weight heparins (LMWH) and can be difficult for the patient to endure in the long term. Here, first, we discuss the clinical trials of primary thromboprophylaxis in the population of cancer patients in general, including the use of VKA, LMWH, and DOACs, and the potential drug interactions with pre-existing medications that need to be taken into account. Second, we focus on special situations in cancer patients where primary prophylactic anticoagulation should be considered, including myeloma, major surgery, indwelling catheters, or immobilization, concomitant diseases such as renal insufficiency, liver disease, or thrombophilia, as well as situations with a high bleeding risk, particularly thrombocytopenia, and specific drugs that may require primary thromboprophylaxis. We provide a novel algorithm intended to aid specialists but also family practitioners and nurses who care for cancer patients in the decision process of primary thromboprophylaxis in the individual patient.

Upper Extremity Deep Vein Thrombosis: Current Knowledge and Future Directions

Upper extremity deep vein thrombosis (UEDVT) has been increasing in incidence due to the escalating use of central venous catheters such as peripherally inserted central catheters. UEDVT can be primary idiopathic or secondary to pacemaker leads, intravascular catheters or cancer. In comparison to conventional venous thromboembolism such as lower limb deep vein thrombosis or pulmonary embolism the risk factors, investigations, and management are not well defined. We review current evidence in primary and secondary UEDVT, highlighting areas in need of further research. We also explore the entity of venous thoracic outlet syndrome, which is said to be a risk factor for recurrent primary UEDVT and is the rationale behind surgical interventions.

American Society of Hematology 2021 guidelines for management of venous thromboembolism: prevention and treatment in patients with cancer

BACKGROUND

Venous thromboembolism (VTE) is a common complication among patients with cancer. Patients with cancer and VTE are at a markedly increased risk for morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the prevention and treatment of VTE in patients with cancer.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The guideline development process was supported by updated or new systematic evidence reviews. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

Recommendations address mechanical and pharmacological prophylaxis in hospitalized medical patients with cancer, those undergoing a surgical procedure, and ambulatory patients receiving cancer chemotherapy. The recommendations also address the use of anticoagulation for the initial, short-term, and long-term treatment of VTE in patients with cancer.

CONCLUSIONS

Strong recommendations include not using thromboprophylaxis in ambulatory patients receiving cancer chemotherapy at low risk of VTE and to use low-molecular-weight heparin (LMWH) for initial treatment of VTE in patients with cancer. Conditional recommendations include using thromboprophylaxis in hospitalized medical patients with cancer, LMWH or fondaparinux for surgical patients with cancer, LMWH or direct oral anticoagulants (DOAC) in ambulatory patients with cancer receiving systemic therapy at high risk of VTE and LMWH or DOAC for initial treatment of VTE, DOAC for the short-term treatment of VTE, and LMWH or DOAC for the long-term treatment of VTE in patients with cancer.

Prophylaxis of thromboembolism during therapy with asparaginase in adults with acute lymphoblastic leukaemia

BACKGROUND

The risk of venous thromboembolism is increased in adults and enhanced by asparaginase-based chemotherapy, and venous thromboembolism introduces a secondary risk of treatment delay and premature discontinuation of key anti-leukaemic agents, potentially compromising survival. Yet, the trade-off between benefits and harms of primary thromboprophylaxis in adults with acute lymphoblastic leukaemia (ALL) treated according to asparaginase-based regimens is uncertain.  OBJECTIVES: The primary objectives were to assess the benefits and harms of primary thromboprophylaxis for first-time symptomatic venous thromboembolism in adults with ALL receiving asparaginase-based therapy compared with placebo or no thromboprophylaxis. The secondary objectives were to compare the benefits and harms of different groups of primary systemic thromboprophylaxis by stratifying the main results per type of drug (heparins, vitamin K antagonists, synthetic pentasaccharides, parenteral direct thrombin inhibitors, direct oral anticoagulants, and blood-derived products for antithrombin substitution).

SEARCH METHODS

We conducted a comprehensive literature search on 02 June 2020, with no language restrictions, including (1) electronic searches of Pubmed/MEDLINE; Embase/Ovid; Scopus/Elsevier; Web of Science Core Collection/Clarivate Analytics; and Cochrane Central Register of Controlled Trials (CENTRAL) and (2) handsearches of (i) reference lists of identified studies and related reviews; (ii) clinical trials registries (ClinicalTrials.gov registry; the International Standard Randomized Controlled Trial Number (ISRCTN) registry; the World Health Organisation's International Clinical Trials Registry Platform (ICTRP); and pharmaceutical manufacturers of asparaginase including Servier, Takeda, Jazz Pharmaceuticals, Ohara Pharmaceuticals, and Kyowa Pharmaceuticals), and (iii) conference proceedings (from the annual meetings of the American Society of Hematology (ASH); the European Haematology Association (EHA); the American Society of Clinical Oncology (ASCO); and the International Society on Thrombosis and Haemostasis (ISTH)). We conducted all searches from 1970 (the time of introduction of asparaginase in ALL treatment). We contacted the authors of relevant studies to identify any unpublished material, missing data, or information regarding ongoing studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs); including quasi-randomised, controlled clinical, cross-over, and cluster-randomised trial designs) comparing any parenteral/oral preemptive anticoagulant or mechanical intervention with placebo or no thromboprophylaxis, or comparing two different pre-emptive anticoagulant interventions in adults aged at least 18 years with ALL treated according to asparaginase-based chemotherapy regimens. For the description of harms, non-randomised observational studies with a control group were eligible for inclusion.  DATA COLLECTION AND ANALYSIS: Using a standardised data collection form, two review authors independently screened and selected studies, extracted data, assessed risk of bias for each outcome using standardised tools (RoB 2.0 tool for RCTs and ROBINS-I tool for non-randomised studies) and the certainty of evidence for each outcome using the GRADE approach. Primary outcomes included first-time symptomatic venous thromboembolism, all-cause mortality, and major bleeding. Secondary outcomes included asymptomatic venous thromboembolism, venous thromboembolism-related mortality, adverse events (i.e. clinically relevant non-major bleeding and heparin-induced thrombocytopenia for trials using heparins), and quality of life. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions. For non-randomised studies, we evaluated all studies (including studies judged to be at critical risk of bias in at least one of the ROBINS-I domains) in a sensitivity analysis exploring confounding.  MAIN RESULTS: We identified 23 non-randomised studies that met the inclusion criteria of this review, of which 10 studies provided no outcome data for adults with ALL. We included the remaining 13 studies in the 'Risk of bias' assessment, in which we identified invalid control group definition in two studies and judged outcomes of nine studies to be at critical risk of bias in at least one of the ROBINS-I domains and outcomes of two studies at serious risk of bias. We did not assess the benefits of thromboprophylaxis, as no RCTs were included. In the main descriptive analysis of harms, we included two retrospective non-randomised studies with outcomes judged to be at serious risk of bias. One study evaluated antithrombin concentrates compared to no antithrombin concentrates. We are uncertain whether antithrombin concentrates have an effect on all-cause mortality (risk ratio (RR) 0.55, 95% confidence interval (CI) 0.26 to 1.19 (intention-to-treat analysis); one study, 40 participants; very low certainty of evidence). We are uncertain whether antithrombin concentrates have an effect on venous thromboembolism-related mortality (RR 0.10, 95% CI 0.01 to 1.94 (intention-to-treat analysis); one study, 40 participants; very low certainty of evidence). We do not know whether antithrombin concentrates have an effect on major bleeding, clinically relevant non-major bleeding, and quality of life in adults with ALL treated with asparaginase-based chemotherapy, as data were insufficient. The remaining study (224 participants) evaluated prophylaxis with low-molecular-weight heparin versus no prophylaxis. However, this study reported insufficient data regarding harms including all-cause mortality, major bleeding, venous thromboembolism-related mortality, clinically relevant non-major bleeding, heparin-induced thrombocytopenia, and quality of life. In the sensitivity analysis of harms, exploring the effect of confounding, we also included nine non-randomised studies with outcomes judged to be at critical risk of bias primarily due to uncontrolled confounding. Three studies (179 participants) evaluated the effect of antithrombin concentrates and six studies (1224 participants) evaluated the effect of prophylaxis with different types of heparins. When analysing all-cause mortality; venous thromboembolism-related mortality; and major bleeding (studies of heparin only) including all studies with extractable outcomes for each comparison (antithrombin and low-molecular-weight heparin), we observed small study sizes; few events; wide CIs crossing the line of no effect; and substantial heterogeneity by visual inspection of the forest plots. Although the observed heterogeneity could arise through the inclusion of a small number of studies with differences in participants; interventions; and outcome assessments, the likelihood that bias due to uncontrolled confounding was the cause of heterogeneity is inevitable. Subgroup analyses were not possible due to insufficient data.  AUTHORS' CONCLUSIONS: We do not know from the currently available evidence, if thromboprophylaxis used for adults with ALL treated according to asparaginase-based regimens is associated with clinically appreciable benefits and acceptable harms. The existing research on this question is solely of non-randomised design, seriously to critically confounded, and underpowered with substantial imprecision. Any estimates of effect based on the existing insufficient evidence is very uncertain and is likely to change with future research.

Antistasis Retrograde Flow Vascular Catheter: A Novel Solution to Thrombogenicity: A Computational Fluid Dynamics Study

BACKGROUND

Catheter-related thrombosis (CRT) is a serious complication of vascular catheters. Retrograde catheter insertion has been shown to decrease pericatheter hemostasis and thrombosis, but it is technically challenging. The current in silico trial is an analytical approach to evaluating different approaches to designing retrograde flow into a vascular catheter.

METHODS

The novel catheter design aims to provide antistasis retrograde flow (ASRF) of fluid through multiple backward-directed side openings, with a self-closing terminal opening to facilitate standard insertion. Four different models of the catheter were evaluated by computational fluid dynamic studies, with retrograde-angled openings of 15°, 30°, 45°, and 60° to the long axis of the catheter.

RESULTS

ASRF successfully reduced the areas of fluid stagnation in models with 15° and 30° openings. Models with 45° and 60° did not significantly reduce stagnation. ASRF is reversed by the main bloodstream after a few millimeters. The novel catheter design achieved a slightly higher saline flow rate compared with the standard catheter (89.75, 91.72, 94.13, and 94.26 mL/min for 15°, 30°, 45°, and 60° designs, respectively, versus 86.93 mL/min for the standard catheter).

CONCLUSIONS

The novel ASRF vascular catheter reduces pericatheter fluid stasis and has the potential to reduce CRT. Further in vitro and in vivo trials are warranted to validate these findings and evaluate clinical efficacy.

Low molecular weight heparin for prevention of central venous catheter-related thrombosis in children

BACKGROUND

The prevalence of children diagnosed with thrombotic events has been increasing in the last decades. The most common thrombosis risk factor in neonates, infants and children is the placement of a central venous catheter (CVC). It is unknown if anticoagulation prophylaxis with low molecular weight heparin (LMWH) decreases CVC-related thrombosis in children. This is an update of the Cochrane Review published in 2014.

OBJECTIVES

To determine the effect of LMWH prophylaxis on the incidence of CVC-related thrombosis and major and minor bleeding complications in children. Further objectives were to determine the effect of LMWH on occlusion of CVCs, number of days of CVC patency, episodes of catheter-related bloodstream infection (CRBSI), other side effects of LMWH (allergic reactions, abnormal coagulation profile, heparin-induced thrombocytopaenia and osteoporosis) and mortality during therapy.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 7 May 2019. We undertook reference checking of identified trials to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-randomised trials comparing LMWH to no prophylaxis (placebo or no treatment), or low-dose unfractionated heparin (UFH) either as continuous infusion or flushes (low-dose UFH aims to ensure the patency of the central line but has no systemic anticoagulation activity), given to prevent CVC-related thrombotic events in children. We selected studies conducted in children aged 0 to 18 years.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified eligible studies, which were assessed for study methodology including bias, and extracted unadjusted data where available. In the data analysis step, all outcomes were analysed as binary or dichotomous outcomes. The effects of interventions were summarised with risk ratios (RR) and their respective 95% confidence intervals (CI). We assessed the certainty of evidence for each outcome using the GRADE approach.

MAIN RESULTS

One additional study was included for this update bringing the total to two included studies (with 1135 participants). Both studies were open-label RCTs comparing LMWH with low-dose UFH to prevent CVC-related thrombosis in children. We identified no studies comparing LMWH with placebo or no treatment. Meta-analysis found insufficient evidence of an effect of LMWH prophylaxis in reducing the incidence of CVC-related thrombosis in children with CVC, compared to low-dose UFH (RR 0.68, 95% CI 0.27 to 1.75; 2 studies; 787 participants; low-certainty evidence). One study (158 participants) reported symptomatic and asymptomatic CVC-related thrombosis separately and detected no evidence of a difference between LMWH and low-dose UFH (RR 1.03, 95% CI 0.21 to 4.93; low-certainty evidence; RR 1.17, 95% CI 0.45 to 3.08; low-certainty evidence; for symptomatic and asymptomatic participants respectively). There was insufficient evidence to determine whether LMWH impacts the risk of major bleeding (RR 0.27, 95% CI 0.05 to 1.67; 2 studies; 813 participants; low-certainty evidence); or minor bleeding. One study reported minor bleeding in 53.3% of participants in the LMWH arm and in 44.7% of participants in the low-dose UFH arm (RR 1.20, 95% CI 0.91 to 1.58; 1 study; 158 participants; very low-certainty evidence), and the other study reported no minor bleeding in either group (RR: not estimable). Mortality during the study period was reported in one study, where two deaths occurred during the study period. Both were unrelated to thrombotic events and occurred in the low-dose UFH arm. The second study did not report mortality during therapy per arm but showed similar 5-year overall survival (low-certainty evidence). No additional adverse effects were reported. Other pre-specified outcomes (including CVC occlusion, patency and CRBSI) were not reported.

AUTHORS' CONCLUSIONS

Pooling data from two RCTs did not provide evidence to support the use of prophylactic LWMH for preventing CVC-related thrombosis in children (low-certainty evidence). Evidence was also insufficient to confirm or exclude a difference in the incidence of major and minor bleeding complications in the LMWH prophylaxis group compared to low-dose UFH (low and very low certainty respectively). No evidence of a clear difference in overall mortality was seen. Studies did not report on the outcomes catheter occlusion, days of catheter patency, episodes of CRBSI and other side effects of LMWH (allergic reactions, abnormal coagulation profile, heparin-induced thrombocytopaenia and osteoporosis). The certainty of the evidence was downgraded due to risk of bias of the included studies, imprecision and inconsistency, preventing conclusions in regards to the efficacy of LMWH prophylaxis to prevent CVC-related thrombosis in children.

Etiology and Management of Upper-Extremity Catheter-Related Thrombosis in Cancer Patients

Central venous access devices are a critical instrument in the treatment and supportive care delivery for oncology patients. Catheter-related thrombosis (CRT) is a common complication of central venous access devices in oncology patients. Risk factors for CRT include patient-, device-, and treatment-related risk factors. Treatment of CRT is indicated to reduce symptoms, prevent catheter malfunction, prevent recurrent DVT or thromboembolic pulmonary embolism, and minimize the risk of post-thrombotic syndrome. Minimal prospective data exist on the prevention and treatment of catheter-related thromboses in cancer patients. As such recommendations largely are derived from data in the lower-extremity DVT and PE studies in cancer and non-cancer patients. Based on the available literature, primary pharmacologic prophylaxis against CRT is not recommended in cancer patients. Treatment options for CRT include catheter removal, anticoagulation, catheter-directed thrombolysis, or surgical thrombectomy. Current evidence-based guidelines recommend LMWH as the anticoagulant of choice. However, recent data showing efficacy and safety of DOACs in cancer-related VTE may be extrapolated to treatment of CRT in cancer patients. In patients with CRT, catheter removal should be pursued if continued vascular access is no longer needed, the catheter is dysfunctional, a catheter-associated infection is present, or if CRT symptoms do not resolve with anticoagulation alone. Catheter-directed thrombolysis is reserved for rare severe cases of CRT. Herein we discuss the pathophysiology, clinical presentation, diagnosis, and general management of CRT in cancer patients.

Heparin versus 0.9% sodium chloride locking for prevention of occlusion in central venous catheters in adults

BACKGROUND

Intermittent locking of central venous catheters (CVCs) is undertaken to help maintain their patency. There are systematic variations in care: some practitioners use heparin (at different concentrations), whilst others use 0.9% NaCl (normal saline). This review looks at the effectiveness and safety of intermittent locking with heparin compared to 0.9% NaCl to see if the evidence establishes whether one is better than the other. This work is an update of a review first published in 2014.

OBJECTIVES

To assess the effectiveness and safety of intermittent locking of CVCs with heparin versus normal saline (NS) in adults to prevent occlusion.

SEARCH METHODS

The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (last searched 11 June 2018) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 5). Searches were also carried out in MEDLINE, Embase, CINAHL, and clinical trials databases (11 June 2018).

SELECTION CRITERIA

We included randomised controlled trials in adults ≥ 18 years of age with a CVC that compared intermittent locking with heparin at any concentration versus NS. We applied no restriction on language.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality, and extracted data. We contacted trial authors to retrieve additional information, when necessary. We carried out statistical analysis using Review Manager 5 and assessed the overall quality of the evidence supporting assessed outcomes using GRADE. We carried out prespecified subgroup analysis.

MAIN RESULTS

We identified five new studies for this update (six prior studies were included in the original review), bringing the number of eligible studies to 11, with a total of 2392 participants. We noted differences in methods used by the included studies and variation in heparin concentrations (10 to 5000 IU/mL), time to follow-up (1 to 251.8 days), and the unit of analysis used (participant, catheter, line access).Combined results from these studies showed fewer occlusions with heparin than with NS (risk ratio (RR) 0.70, 95% confidence interval (CI) 0.51 to 0.95; P = 0.02; 1672 participants; 1025 catheters from 10 studies; I² = 14%) and provided very low-quality evidence.We carried out subgroup analysis by unit of analysis (testing for subgroup differences (P = 0.23; I² = 30.3%). When the unit of analysis was the participant, results show no clear differences in all occlusions between heparin and NS (RR 0.79, 95% CI 0.58 to 1.08; P = 0.15; 1672 participants; seven studies). Subgroup analysis using the catheter as the unit of analysis shows fewer occlusions with heparin use (RR 0.53, 95% CI 0.29 to 0.95; P = 0.03; 1025 catheters; three studies). When the unit of analysis was line access, results show no clear differences in occlusions between heparin and NS (RR 1.08, 95% CI 0.84 to 1.40; 770 line accesses; one study).We found no clear differences in the duration of catheter patency (mean difference (MD) 0.44 days, 95% CI -0.10 to 0.99; P = 0.11; 1036 participants; 752 catheters; six studies; low-quality evidence).We found no clear evidence of a difference in the following: CVC-related sepsis (RR 0.74, 95% CI 0.03 to 19.54; P = 0.86; 1097 participants; two studies; low-quality evidence); mortality (RR 0.76, 95% CI 0.44 to 1.31; P = 0.33; 1100 participants; three studies; low-quality evidence); haemorrhage at any site (RR 1.32, 95% CI 0.57 to 3.07; P = 0.52; 1245 participants; four studies; moderate-quality evidence); or heparin-induced thrombocytopaenia (RR 0.21, 95% CI 0.01 to 4.27; P = 0.31; 443 participants; three studies; low-quality evidence).The main reasons for downgrading the quality of evidence were unclear allocation concealment, imprecision, and suspicion of publication bias.

AUTHORS' CONCLUSIONS

Given the very low quality of the evidence, we are uncertain whether intermittent locking with heparin results in fewer occlusions than intermittent locking with NS. Low-quality evidence suggests that heparin may have little or no effect on catheter patency. Although we found no evidence of differences in safety (sepsis, mortality, or haemorrhage), the combined trials are not powered to detect rare adverse events such as heparin-induced thrombocytopaenia.

Anticoagulation for people with cancer and central venous catheters

BACKGROUND

Central venous catheter (CVC) placement increases the risk of thrombosis in people with cancer. Thrombosis often necessitates the removal of the CVC, resulting in treatment delays and thrombosis-related morbidity and mortality. This is an update of the Cochrane Review published in 2014.

OBJECTIVES

To evaluate the efficacy and safety of anticoagulation for thromboprophylaxis in people with cancer with a CVC.

SEARCH METHODS

We conducted a comprehensive literature search in May 2018 that included a major electronic search of Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid), and Embase (Ovid); handsearching of conference proceedings; checking of references of included studies; searching for ongoing studies; and using the 'related citation' feature in PubMed. This update of the systematic review was based on the findings of a literature search conducted on 14 May 2018.

SELECTION CRITERIA

Randomized controlled trials (RCTs) assessing the benefits and harms of unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), vitamin K antagonists (VKA), or fondaparinux or comparing the effects of two of these anticoagulants in people with cancer and a CVC.

DATA COLLECTION AND ANALYSIS

Using a standardized form, we extracted data and assessed risk of bias. Outcomes included all-cause mortality, symptomatic catheter-related venous thromboembolism (VTE), pulmonary embolism (PE), major bleeding, minor bleeding, catheter-related infection, thrombocytopenia, and health-related quality of life (HRQoL). We assessed the certainty of evidence for each outcome using the GRADE approach (Balshem 2011).

MAIN RESULTS

Thirteen RCTs (23 papers) fulfilled the inclusion criteria. These trials enrolled 3420 participants. Seven RCTs compared LMWH to no LMWH (six in adults and one in children), six RCTs compared VKA to no VKA (five in adults and one in children), and three RCTs compared LMWH to VKA in adults.LMWH versus no LMWHSix RCTs (1537 participants) compared LMWH to no LMWH in adults. The meta-analyses showed that LMWH probably decreased the incidence of symptomatic catheter-related VTE up to three months of follow-up compared to no LMWH (risk ratio (RR) 0.43, 95% confidence interval (CI) 0.22 to 0.81; risk difference (RD) 38 fewer per 1000, 95% CI 13 fewer to 52 fewer; moderate-certainty evidence). However, the analysis did not confirm or exclude a beneficial or detrimental effect of LMWH on mortality at three months of follow-up (RR 0.82, 95% CI 0.53 to 1.26; RD 14 fewer per 1000, 95% CI 36 fewer to 20 more; low-certainty evidence), major bleeding (RR 1.49, 95% CI 0.06 to 36.28; RD 0 more per 1000, 95% CI 1 fewer to 35 more; very low-certainty evidence), minor bleeding (RR 1.35, 95% CI 0.62 to 2.92; RD 14 more per 1000, 95% CI 16 fewer to 79 more; low-certainty evidence), and thrombocytopenia (RR 1.03, 95% CI 0.80 to 1.33; RD 5 more per 1000, 95% CI 35 fewer to 58 more; low-certainty evidence).VKA versus no VKAFive RCTs (1599 participants) compared low-dose VKA to no VKA in adults. The meta-analyses did not confirm or exclude a beneficial or detrimental effect of low-dose VKA compared to no VKA on mortality (RR 0.99, 95% CI 0.64 to 1.55; RD 1 fewer per 1000, 95% CI 34 fewer to 52 more; low-certainty evidence), symptomatic catheter-related VTE (RR 0.61, 95% CI 0.23 to 1.64; RD 31 fewer per 1000, 95% CI 62 fewer to 51 more; low-certainty evidence), major bleeding (RR 7.14, 95% CI 0.88 to 57.78; RD 12 more per 1000, 95% CI 0 fewer to 110 more; low-certainty evidence), minor bleeding (RR 0.69, 95% CI 0.38 to 1.26; RD 15 fewer per 1000, 95% CI 30 fewer to 13 more; low-certainty evidence), premature catheter removal (RR 0.82, 95% CI 0.30 to 2.24; RD 29 fewer per 1000, 95% CI 114 fewer to 202 more; low-certainty evidence), and catheter-related infection (RR 1.17, 95% CI 0.74 to 1.85; RD 71 more per 1000, 95% CI 109 fewer to 356; low-certainty evidence).LMWH versus VKAThree RCTs (641 participants) compared LMWH to VKA in adults. The available evidence did not confirm or exclude a beneficial or detrimental effect of LMWH relative to VKA on mortality (RR 0.94, 95% CI 0.56 to 1.59; RD 6 fewer per 1000, 95% CI 41 fewer to 56 more; low-certainty evidence), symptomatic catheter-related VTE (RR 1.83, 95% CI 0.44 to 7.61; RD 15 more per 1000, 95% CI 10 fewer to 122 more; very low-certainty evidence), PE (RR 1.70, 95% CI 0.74 to 3.92; RD 35 more per 1000, 95% CI 13 fewer to 144 more; low-certainty evidence), major bleeding (RR 3.11, 95% CI 0.13 to 73.11; RD 2 more per 1000, 95% CI 1 fewer to 72 more; very low-certainty evidence), or minor bleeding (RR 0.95, 95% CI 0.20 to 4.61; RD 1 fewer per 1000, 95% CI 21 fewer to 95 more; very low-certainty evidence). The meta-analyses showed that LMWH probably increased the risk of thrombocytopenia compared to VKA at three months of follow-up (RR 1.69, 95% CI 1.20 to 2.39; RD 149 more per 1000, 95% CI 43 fewer to 300 more; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence was not conclusive for the effect of LMWH on mortality, the effect of VKA on mortality and catheter-related VTE, and the effect of LMWH compared to VKA on mortality and catheter-related VTE. We found moderate-certainty evidence that LMWH reduces catheter-related VTE compared to no LMWH. People with cancer with CVCs considering anticoagulation should balance the possible benefit of reduced thromboembolic complications with the possible harms and burden of anticoagulants.

Risk associated with central catheters for malignant tumor patients: a systematic review and meta-analysis

The risk of venous thrombosis and mortality associated with central catheter (PICC/CICC) for malignant tumor patients is not definite. So, we carried out a systematic review and meta-analysis to evaluate it. Among patients with comparing PICC with CICC, odds ratio (OR) or risk ratio (RR) was calculated with a random effect model meta-analysis. The result of the stratification analysis of 7 studies (PICC vs CICC) supported the theory that CICCs were associated with a decrease in the odds ratio of thrombosis compared with PICCs. 7 of 15 studies provided the information about the compared mortality rate of the patients. The result showed that CICCs were associated with a decrease in the odds ratio of thrombosis compared with PICCs (OR = 0.45, 95% CI:0.32-0.62, p < 0.0001, I2 = 0%,Tau2 = 0.00). Meta-analysis of 8 studies of 2639 patients showed that pharmacological deep vein thrombosis prophylaxis drugs could decrease the risk of mortality of malignant tumor patients with CICCs (RR = 0.58, 95% CI:0.48-0.71, Z = 5.32, p < 0.0001, I2 = 71%). We found that PICCs are associated with a raised risk of deep vein thrombosis, and pharmacological deep vein thrombosis prophylaxis drugs is a beneficial factor in decreasing the incidence of thrombosis, while warfarin may decrease the risk of mortality of malignant tumor patients with CICCs.

Incidence, risk factors, and outcomes of central venous catheter-related thromboembolism in breast cancer patients: the CAVECCAS study

Previous epidemiologic studies investigating central venous catheter (CVC)‐related venous thromboembolism (CRT) were conducted in heterogenous cancer populations and data in breast cancer (BC) remain limited. To investigate the Doppler ultrasound (DUS)‐CRT incidence, risk factors and outcomes in BC, we designed a prospective, multicenter cohort of nonmetastatic invasive BC patients undergoing insertion of a CVC for chemotherapy. All patients underwent double‐blind DUS before, 7, 30, and 90 days after CVC insertion and a 6 months clinical follow‐up. Symptomatic DUS‐CRT were treated by anticoagulants. D‐Dimers, thrombin generation, and platelet‐derived microparticles were measured before and 2 days after CVC placement. In DUS‐CRT patients, a nested case–control study analyzed the role of thrombophilia. Among 524 patients, the DUS‐CRT (14 symptomatic, 46 asymptomatic) cumulative probability was 9.6% at 3 months and 11.5% at 6 months (overall incidence rate: 2.18/100 patient‐months). Ten/14 symptomatic DUS‐CRT were detected on double‐blind DUS before the clinical symptoms, and 3/14 had a simultaneous pulmonary embolism. No clinical thrombotic event subsequently occurred in untreated asymptomatic DUS‐CRT. Age >50 years (OR, 1.80; 95% CI, 1.01–3.22), BMI >30 kg/m² (OR, 2.64; 95% CI, 1.46–4.76) and comorbidities (OR, 2.05; 95% CI, 1.18–3.56) were associated with DUS‐CRT. No biomarkers was found to predict DUS‐CRT. In multivariate analysis, BMI >30 kg/m² (OR, 2.66; 95%CI, 1.46–4.84) and lobular carcinoma histology (OR, 2.56; 95%CI, 1.32–4.96) remained the only significant DUS‐CRT risk factors. Thrombophilia did not account for DUS‐CRT. Only clinical parameters identified high risk DUS‐CRT patients who may be considered for thromboprophylaxis.

Parenteral anticoagulation in ambulatory patients with cancer

BACKGROUND

Anticoagulation may improve survival in patients with cancer through a speculated anti-tumour effect, in addition to the antithrombotic effect, although may increase the risk of bleeding.

OBJECTIVES

To evaluate the efficacy and safety of parenteral anticoagulants in ambulatory patients with cancer who, typically, are undergoing chemotherapy, hormonal therapy, immunotherapy or radiotherapy, but otherwise have no standard therapeutic or prophylactic indication for anticoagulation.

SEARCH METHODS

A comprehensive search included (1) a major electronic search (February 2016) of the following databases: Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 1), MEDLINE (1946 to February 2016; accessed via OVID) and Embase (1980 to February 2016; accessed via OVID); (2) handsearching of conference proceedings; (3) checking of references of included studies; (4) use of the 'related citation' feature in PubMed and (5) a search for ongoing studies in trial registries. As part of the living systematic review approach, we are running searches continually and we will incorporate new evidence rapidly after it is identified. This update of the systematic review is based on the findings of a literature search conducted on 14 August, 2017.

SELECTION CRITERIA

Randomized controlled trials (RCTs) assessing the benefits and harms of parenteral anticoagulation in ambulatory patients with cancer. Typically, these patients are undergoing chemotherapy, hormonal therapy, immunotherapy or radiotherapy, but otherwise have no standard therapeutic or prophylactic indication for anticoagulation.

DATA COLLECTION AND ANALYSIS

Using a standardized form we extracted data in duplicate on study design, participants, interventions outcomes of interest, and risk of bias. Outcomes of interested included all-cause mortality, symptomatic venous thromboembolism (VTE), symptomatic deep vein thrombosis (DVT), pulmonary embolism (PE), major bleeding, minor bleeding, and quality of life. We assessed the certainty of evidence for each outcome using the GRADE approach (GRADE handbook).

MAIN RESULTS

Of 6947 identified citations, 18 RCTs fulfilled the eligibility criteria. These trials enrolled 9575 participants. Trial registries' searches identified nine registered but unpublished trials, two of which were labeled as 'ongoing trials'. In all included RCTs, the intervention consisted of heparin (either unfractionated heparin or low molecular weight heparin). Overall, heparin appears to have no effect on mortality at 12 months (risk ratio (RR) 0.98; 95% confidence interval (CI) 0.93 to 1.03; risk difference (RD) 10 fewer per 1000; 95% CI 35 fewer to 15 more; moderate certainty of evidence) and mortality at 24 months (RR 0.99; 95% CI 0.96 to 1.01; RD 8 fewer per 1000; 95% CI 31 fewer to 8 more; moderate certainty of evidence). Heparin therapy reduces the risk of symptomatic VTE (RR 0.56; 95% CI 0.47 to 0.68; RD 30 fewer per 1000; 95% CI 36 fewer to 22 fewer; high certainty of evidence), while it increases in the risks of major bleeding (RR 1.30; 95% 0.94 to 1.79; RD 4 more per 1000; 95% CI 1 fewer to 11 more; moderate certainty of evidence) and minor bleeding (RR 1.70; 95% 1.13 to 2.55; RD 17 more per 1000; 95% CI 3 more to 37 more; high certainty of evidence). Results failed to confirm or to exclude a beneficial or detrimental effect of heparin on thrombocytopenia (RR 0.69; 95% CI 0.37 to 1.27; RD 33 fewer per 1000; 95% CI 66 fewer to 28 more; moderate certainty of evidence); quality of life (moderate certainty of evidence).

AUTHORS' CONCLUSIONS

Heparin appears to have no effect on mortality at 12 months and 24 months. It reduces symptomatic VTE and likely increases major and minor bleeding. Future research should further investigate the survival benefit of different types of anticoagulants in patients with different types and stages of cancer. The decision for a patient with cancer to start heparin therapy should balance the benefits and downsides, and should integrate the patient's values and preferences.Editorial note:This is a living systematic review. Living systematic reviews offer a new approach to review updating in which the review is continually updated, incorporating relevant new evidence, as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

How I treat central venous access device-related upper extremity deep vein thrombosis

Central venous access device (CVAD)-related thrombosis (CRT) is a common complication among patients requiring central venous access as part of their medical care. Complications of CRT include pulmonary embolism, recurrent deep venous thrombosis, loss of central venous access, and postthrombotic syndrome. Patient-, device-, and treatment-related factors can influence the risk of CRT. Despite numerous randomized controlled trials, the clinical benefit of pharmacologic thromboprophylaxis for the prevention of CRT remains to be established. Therefore, minimizing patient exposure to known risk factors is the best available approach to prevent CRT. Venous duplex is recommended for the diagnosis of CRT. Anticoagulation for at least 3 months or the duration of the indwelling CVAD is recommended for treatment of CRT. Thrombolysis should be considered for patients at low risk for bleeding who have limb-threatening thrombosis or whose symptoms fail to resolve with adequate anticoagulation. CVAD removal should be consider for patients with bacteremia, persistent symptoms despite anticoagulation, and if the CVAD is no longer needed. Superior vena cava filters should be avoided. Prospective studies are needed to define the optimal management of patients with or at risk for CRT.

Randomized controlled trials in central vascular access devices: A scoping review

BACKGROUND

Randomized controlled trials evaluate the effectiveness of interventions for central venous access devices, however, high complication rates remain. Scoping reviews map the available evidence and demonstrate evidence deficiencies to focus ongoing research priorities.

METHOD

A scoping review (January 2006-December 2015) of randomized controlled trials evaluating the effectiveness of interventions to improve central venous access device outcomes; including peripherally inserted central catheters, non-tunneled, tunneled and totally implanted venous access catheters. MeSH terms were used to undertake a systematic search with data extracted by two independent researchers, using a standardized data extraction form.

RESULTS

In total, 178 trials were included (78 non-tunneled [44%]; 40 peripherally inserted central catheters [22%]; 20 totally implanted [11%]; 12 tunneled [6%]; 6 non-specified [3%]; and 22 combined device trials [12%]). There were 119 trials (68%) involving adult participants only, with 18 (9%) pediatric and 20 (11%) neonatal trials. Insertion-related themes existed in 38% of trials (67 RCTs), 35 RCTs (20%) related to post-insertion patency, with fewer trials on infection prevention (15 RCTs, 8%), education (14RCTs, 8%), and dressing and securement (12 RCTs, 7%). There were 46 different study outcomes reported, with the most common being infection outcomes (161 outcomes; 37%), with divergent definitions used for catheter-related bloodstream and other infections.

CONCLUSION

More high quality randomized trials across central venous access device management are necessary, especially in dressing and securement and patency. These can be encouraged by having more studies with multidisciplinary team involvement and consumer engagement. Additionally, there were extensive gaps within population sub-groups, particularly in tunneled devices, and in pediatrics and neonates. Finally, outcome definitions need to be unified for results to be meaningful and comparable across studies.

A phase II study on the efficacy and safety of procedural analgesia with fentanyl buccal tablet in cancer patients for the placement of indwelling central venous access systems

Background

Pain in cancer patients is often related to oncologic therapies and diagnostic procedures. The placement of fully implantable venous access systems is a very common procedure in oncology patients. Local anaesthesia is the method most commonly used to overcome pain related to this surgical procedure, but the local anaesthetic may be unable to completely eradicate all pain. This study investigates the effectiveness and safety of fentanyl buccal tablet (FBT), administered by OraVescent® technology, in reducing procedural pain related to the placement of indwelling central venous access systems (Ports) in opioid-naïve cancer patients.

Methods

Inpatients who required an indwelling vascular access (Port) were preoperatively assessed with a self-assessment questionnaire on anxiety and pain. A 100 μg FBT was administered 10 min before preparation of the operating field. A self-assessment scale for pain experienced during the procedure was administered at the end of the procedure. Vital signs and the presence of any side effects or bothersome symptoms were monitored during the procedure, at the end, and 4 h later.

Results

From October 2012 to June 2014, 65 patients were enrolled in the study. A total of 61 (93.9 %) patients perceived no or a little pain during the procedure. Four patients (6.2 %) reported a lot of pain. No patient reported very severe pain. This data is significant in terms of the lower than expected presence of pain (Fisher test p = 0.0018) as assessed in our previous experience without procedural analgesia. The most common side effects of FBT was drowsiness, experienced by 28 patients at the end of the procedure (43.1 %), significantly reduced (p < 0.01) to 8 patients after 4 h (12.5 %). Nausea was present in 6 cases at the end of the procedure (9.2 %) and in 7 cases 4 h later (10.9 %). Vomiting was present in 3 cases at the end (4.7 %) and in 2 other patients after 4 h (7.8 %). No significant change of vital parameters was observed between the baseline and the subsequent measurements in all patients studied.

Conclusions

The significant improvement in the number of patients experiencing little or no pain, accompanied by a lower number of non-severe side effects, suggests that FBT is a valid, practical and safe method of procedural analgesia. It will be necessary to perform further studies, taking into account the need for standard antiemetic pre-medication to minimise the incidence of nausea and vomiting.

Canadian consensus recommendations on the management of venous thromboembolism in patients with cancer. Part 1: prophylaxis

Patients with cancer are at increased risk of venous thromboembolism (vte). Anticoagulation therapy has been shown to prevent vte; however, unique clinical circumstances in patients with cancer can often complicate the decisions surrounding the administration of prophylactic anticoagulation. No national Canadian guidelines on the prevention of cancer-associated thrombosis have been published. We therefore aimed to develop a consensus-based, evidence-informed guideline on the topic. PubMed was searched for clinical trials and meta-analyses published between 2002 and 2013. Reference lists of key articles were hand-searched for additional publications. Content experts from across Canada were assembled to review the evidence and make recommendations. Low molecular weight heparin can be used prophylactically in cancer patients at high risk of developing vte. Direct oral anticoagulants are not recommended for vte prophylaxis at this time. Specific clinical scenarios, including renal insufficiency, thrombocytopenia, liver disease, and obesity can warrant modifications in the administration of prophylactic anticoagulant therapy. There is no evidence to support the monitoring of anti-factor Xa levels in clinically stable cancer patients receiving prophylactic anticoagulation; however, factor Xa levels could be checked at baseline and periodically in patients with renal insufficiency. The use of anticoagulation therapy to prolong survival in cancer patients without the presence of risk factors for vte is not recommended.

Parenteral anticoagulation in ambulatory patients with cancer

BACKGROUND

Anticoagulation may improve survival in patients with cancer through an antitumor effect in addition to the perceived antithrombotic effect.

OBJECTIVES

To evaluate the efficacy and safety of parenteral anticoagulants in ambulatory patients with cancer who, typically, are undergoing chemotherapy, hormonal therapy or radiotherapy, but otherwise have no standard therapeutic or prophylactic indication for anticoagulation.

SEARCH METHODS

A comprehensive search included (1) an electronic search (February 2013) of the following databases: Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 1), MEDLINE (1966 to February 2013; accessed via OVID) and EMBASE(1980 to February 2013; accessed via OVID); (2) handsearching of conference proceedings; (3) checking of references of included studies; (4) use of the 'related citation' feature in PubMed and (5) a search for ongoing studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) assessing the benefits and harms of parenteral anticoagulation in ambulatory patients with cancer. Typically, these patients are undergoing chemotherapy, hormonal therapy or radiotherapy, but otherwise have no standard therapeutic or prophylactic indication for anticoagulation.

DATA COLLECTION AND ANALYSIS

Using a standardized form we extracted data in duplicate on methodological quality, participants, interventions and outcomes of interest including all-cause mortality, symptomatic venous thromboembolism (VTE), symptomatic deep vein thrombosis (DVT), symptomatic pulmonary embolism (PE), arterial thrombosis (e.g. stroke, myocardial infarction), major bleeding, minor bleeding and quality of life.

MAIN RESULTS

Of 9559 identified citations, 15 RCTs fulfilled the eligibility criteria. These trials enrolled 7622 participants for whom follow-up data were available. In all included RCTs the intervention consisted of heparin (either unfractionated heparin or low molecular weight heparin). Overall, heparin may have a small effect on mortality at 12 months and 24 months (risk ratio (RR) 0.97; 95% confidence interval (CI) 0.92 to 1.01 and RR 0.95; 95% CI 0.90 to 1.00, respectively). Heparin therapy was associated with a statistically and clinically important reduction in venous thromboembolism (RR 0.56; 95% CI 0.42 to 0.74) and a clinically important increase in the risk of minor bleeding (RR 1.32; 95% 1.02 to 1.71). Results failed to show or to exclude a beneficial or detrimental effect of heparin on major bleeding (RR 1.14; 95% CI 0.70 to 1.85) or quality of life. Our confidence in the effect estimates (i.e. quality of evidence) was high for symptomatic venous thromboembolism, moderate for mortality, major bleeding and minor bleeding, and low for quality of life.

AUTHORS' CONCLUSIONS

Heparin may have a small effect on mortality at 12 months and 24 months. It is associated with a reduction in venous thromboembolism and a likely increase in minor bleeding. Future research should further investigate the survival benefit of different types of anticoagulants in patients with different types and stages of cancer. The decision for a patient with cancer to start heparin therapy for survival benefit should balance the benefits and downsides, and should integrate the patient's values and preferences.

Central venous catheter-related thrombosis

Thrombotic complications associated with the use of central venous catheters (CVCs) are common and lead to distressing patient symptoms, catheter dysfunction, increased risk of infections, long-term central venous stenosis, and considerable costs of care. Risk factors for catheter-related thrombosis include use of larger, multilumen, and peripherally inserted catheters in patients with cancer receiving chemotherapy. Symptomatic catheter-related thrombosis is treated with anticoagulation, generally without removing the catheter. The intensity and duration of anticoagulation depend on the extent of thrombosis, risk of bleeding, and need for continued use of a CVC. To date, the clinical benefit of prophylactic doses of anticoagulant has been disappointing and these agents are not used routinely for this purpose. This chapter focuses on recent evidence, remaining controversies, and practical approaches to reducing the burden of thrombosis associated with CVCs.

Anticoagulation for people with cancer and central venous catheters

BACKGROUND

Central venous catheter (CVC) placement increases the risk of thrombosis in people with cancer. Thrombosis often necessitates the removal of the CVC, resulting in treatment delays and thrombosis-related morbidity and mortality.

OBJECTIVES

To evaluate the relative efficacy and safety of anticoagulation for thromboprophylaxis in people with cancer with a CVC.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 12, 2012), MEDLINE Ovid (January 1966 to February 2013), and EMBASE Ovid (1980 to February 2013). We handsearched conference proceedings, checked references of included studies, used the 'related citations' feature within PubMed, and searched clinicaltrials.gov for ongoing studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing the effects of any dose of unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), vitamin K antagonists (VKA), or fondaparinux with no intervention or placebo or comparing the effects of two different anticoagulants in people with cancer and a CVC.

DATA COLLECTION AND ANALYSIS

Teams of two review authors independently used a standardized form to extract data in duplicate. They resolved any disagreements by discussion. They extracted data on risk of bias, participants, interventions, and outcomes. Outcomes of interest included mortality, symptomatic deep venous thrombosis (DVT), asymptomatic DVT, major bleeding, minor bleeding, infection, and thrombocytopenia. Where possible, we conducted meta-analyses using the random-effects model.

MAIN RESULTS

Of 9559 identified citations, we included 12 RCTs (17 publications) reporting follow-up data on 2823 participants. Two of the RCTs included children. Of the 10 RCTs including 2564 adults, one compared prophylactic dose heparin with low-dose VKA. Three RCTs compared VKA with no VKA and four RCTs compared heparin with no heparin. Two additional trials had three separate arms comparing heparin, VKA, and no intervention. Prophylactic-dose heparin, compared with no heparin, was associated with a statistically significant reduction in symptomatic DVT (risk ratio (RR) 0.48; 95% confidence interval (CI) 0.27 to 0.86; moderate-quality evidence). However, results did not confirm or exclude a beneficial or detrimental effect of heparin on mortality (RR 0.82; 95% CI 0.53 to 1.26; moderate-quality evidence), major bleeding (RR 0.49; 95% CI 0.03 to 7.84; low-quality evidence), infection (RR 1.00; 95% CI 0.54 to 1.85; moderate-quality evidence); thrombocytopenia (RR 1.03; 95% CI 0.80 to 1.33; moderate-quality evidence), or minor bleeding (RR 1.35; 95% CI: 0.62 to 2.92). Low-dose VKAs, compared with no VKAs, were associated with a statistically significant reduction in asymptomatic DVT (RR 0.43; 95% CI 0.30 to 0.62). Results did not confirm or exclude a beneficial or detrimental effect of VKAs on mortality (RR 1.04; 95% CI 0.89 to 1.22; low-quality evidence), symptomatic DVT (RR 0.51; 95% CI 0.21 to 1.22; low-quality evidence), major bleeding (RR 7.60; 95% CI 0.94 to 61.49; very-low-quality evidence), or minor bleeding (RR 3.14; 95% CI 0.14 to 71.51). The use of heparin, compared with VKA was associated with a statistically significant increase in thrombocytopenia (RR 3.73; 95% CI 2.26 to 6.16; low-quality evidence) and asymptomatic DVT (RR 1.74; 95% CI 1.20 to 2.52). However, results did not show or exclude a beneficial or detrimental effect on any of the other outcomes of interest (very-low-quality evidence).

AUTHORS' CONCLUSIONS

Compared with no anticoagulation, we found a statistically significant reduction of symptomatic DVT with heparin and asymptomatic DVT with VKA. Heparin was associated with a higher risk of thrombocytopenia and asymptomatic DVT when compared with VKA. However, the findings did not rule out other clinically important benefits and harms. People with cancer with CVCs considering anticoagulation should balance the possible benefit of reduced thromboembolic complications with the possible harms and burden of anticoagulants.

Heparin versus 0.9% sodium chloride intermittent flushing for prevention of occlusion in central venous catheters in adults

BACKGROUND

Heparin intermittent flushing is a standard practice in the maintenance of patency in central venous catheters. However, we could find no systematic review examining its effectiveness and safety.

OBJECTIVES

To assess the effectiveness of intermittent flushing with heparin versus 0.9% sodium chloride (normal saline) solution in adults with central venous catheters in terms of prevention of occlusion and overall benefits versus harms.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched December 2013) and the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11). Searches were also carried out in MEDLINE, EMBASE, CINAHL and clinical trials databases (December 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) in adults 18 years of age and older with a central venous catheter (CVC) in which intermittent flushing with heparin (any dose with or without other drugs) was compared with 0.9% normal saline were included. No restriction on language was applied.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data. Trial authors were contacted to retrieve additional information, when necessary.

MAIN RESULTS

Six eligible studies with a total of 1433 participants were included. The heparin concentrations used in these studies were very different (10-5000 IU/mL), and follow-up varied from 20 days to 180 days. The overall risk of bias in the studies was low. The quality of the evidence ranged from very low to moderate for the main outcomes (occlusion of CVC, duration of catheter patency, CVC-related sepsis, mortality and haemorrhage at any site).Combined findings from three trials in which the unit of analysis was the catheter suggest that heparin was associated with reduced CVC occlusion rates (risk ratio (RR) 0.53, 95% confidence interval (CI) 0.29 to 0.94). However, no clear evidence of a similar effect was found when the results of two studies in which the unit of analysis was the participant were combined (RR 0.21, 95% CI 0.03 to 1.70), nor when findings were derived from one study, which considered total line accesses (RR 1.08, 95% CI 0.84 to 1.40). Furthermore, results for other estimated effects were found to be imprecise and compatible with benefit and harm: catheter duration in days (mean difference (MD) 0.41, 95% CI -1.29 to 2.12), CVC-related thrombosis (RR 1.22, 95% CI 0.74 to 1.99), CVC-related sepsis (RR 1.02, 95% CI 0.34 to 3.03), mortality (RR 0.77, 95% CI 0.45 to 1.32) and haemorrhage at any site (RR 1.37, 95% CI 0.49 to 3.85).

AUTHORS' CONCLUSIONS

We found no conclusive evidence of important differences when heparin intermittent flushing was compared with 0.9% normal saline flushing for central venous catheter maintenance in terms of efficacy or safety. As heparin is more expensive than normal saline, our findings challenge its continued use in CVC flushing outside the context of clinical trials.

Low molecular weight heparin for prevention of central venous catheterization-related thrombosis in children

BACKGROUND

The prevalence of children diagnosed with deep vein thrombosis or pulmonary embolism has been increasing in the last decade. The most common thrombosis risk factor in neonates, infants and children is the placement of a central venous catheter (CVC). To date, it is unknown if the practice of anticoagulation prophylaxis with low molecular weight heparin (LMWH) decreases CVC-related thrombosis in children.

OBJECTIVES

The primary objective of this review was to determine the effect of LMWH prophylaxis on reducing the incidence of CVC-related thrombosis in children.Secondary objectives were to determine the effect of LMWH on occlusion of CVCs, number of days of CVC patency, episodes of catheter-related sepsis, side effects of LMWH (allergic reactions, major and minor bleeding complications, abnormal coagulation profile, osteoporosis) and mortality during therapy.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched June 2013), CENTRAL (2013, Issue 5) and clinical trial databases. The authors searched MEDLINE and EMBASE (July 2013). Bibliographies of identified articles were searched. There were no language restrictions.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing LMWH prophylaxis to standard care given to prevent CVC-related thrombotic events in children were included. We selected studies conducted in children aged 0 to 18 years.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified eligible studies, which were assessed for study quality including bias, and extracted unadjusted data where available. In the data analysis step, all outcomes were analysed as binary or dichotomous outcomes. The effects of interventions were summarised with risk ratios (RR) and their respective 95% confidence intervals (CI).

MAIN RESULTS

One of 17 studies retrieved for full-text assessment for eligibility was included in the final analysis. This study included a total of 186 participants and investigated the effect of LMWH to prevent CVC-related thrombosis compared to standard care. The risk of bias of the study was assessed to be low, except for the unclear risk of selection bias (allocation concealment not reported) and detection bias since it was an open-label study. Nonetheless, outcome adjudication was blinded. However, overall the quality of the evidence was low due to the fact that the study was underpowered. The CIs for the risk of CVC-related thrombosis (symptomatic and asymptomatic events) were compatible with benefits of either LMWH (reviparin) or the control (RR for symptomatic thrombosis 1.03, 95% CI 0.21 to 4.93; RR for asymptomatic thrombosis 1.17, 95% CI 0.45 to 3.08). Similarly, only one patient in the standard care group suffered a major bleeding event, while minor bleeding was found in 53.3% of patients in the reviparin arm and in 44.7% of patients in the standard care arm (major bleeding RR 0.34, 95% CI 0.01 to 8.26; minor bleeding RR 1.20, 95% CI 0.91 to 1.58). Lastly, there were two deaths within the study and neither were the result of a venous thrombotic event (VTE), occurring in the standard care arm. No additional adverse effects were reported. Other pre-specified outcomes for this review were not reported.

AUTHORS' CONCLUSIONS

A single study reported imprecise effects for the risk of CVC-related thrombosis in children on a CVC anticoagulant prophylaxis regimen. The quality of the evidence was low due to the fact that the included study was clearly underpowered, hampering any conclusions in regards to the efficacy of LMWH prophylaxis to prevent CVC-related thrombi in children. Further prospective randomised studies are highly encouraged.

Catheter-related thrombosis in cancer patients

Central venous catheters are commonly used in haematology departments for the administration of chemotherapy, blood products and parenteral nutrition in patients with haematological malignancy. Thrombosis is a recognized complication of such devices especially in oncology patients. Catheter-related thrombi (CRT) may lead to pulmonary embolism and infection, as well as catheter failure and potential delays in treatment. The vast majority of CRT are asymptomatic, thus a high index of suspicion is required in making the diagnosis. Doppler ultrasound or venography may be employed to identify CRT. Once confirmed, the initiation of treatment is a balance between the risks of anticoagulation against potential complications of CRT. A number of risk factors for CRT are discussed along with an overview of catheter types, their appropriate choice and intravascular positioning.

Venous access catheter-related thrombosis in patients with cancer

Patients with cancer are at high risk for developing venous thromboembolism (VTE), and the presence of a central venous catheter (CVC) further increases this risk. CVC-related VTE has serious implications related to the loss of vascular access, development of pulmonary embolism, recurrent VTE, infections and post-thrombotic syndrome. The pathogenesis of CVC-related VTE is complex and multifactorial, with risk factors associated with the catheter, the vessel selected for insertion and the underlying cancer as well as the anti-cancer therapy. Clinical presentation of CVC-related VTEs is often non-specific, and ultrasonography is the most commonly used radiological diagnostic test. Management of CVC-related VTE in patients with cancer requires a balance between the need for venous access, the risk of VTE recurrence and the risk of bleeding from treatment-induced thrombocytopenia. Effective VTE prophylaxis methods have yet to be defined. Ongoing studies are evaluating the role of newer oral antithrombotic agents and alternative interventional strategies for the prevention and treatment of CVC-related VTE in patients with cancer.

Prophylaxis of catheter-related deep vein thrombosis in cancer patients with low-dose warfarin, low molecular weight heparin, or control: a randomized, controlled, phase III study

PURPOSE

Whether an anticoagulant prophylaxis is needed for patients with cancer with a central venous catheter is a highly controversial subject. We designed a study to compare different prophylactic strategies over 3 months of treatment.

METHODS

We performed a phase III prospective, open-label randomized trial. After the insertion of a central venous access device, consecutive patients with planned chemotherapy for cancer were randomized to no anticoagulant prophylaxis, low molecular weight heparin [low molecular weight heparin (LMWH); with isocoagulation doses], or warfarin 1 mg/day. Treatments were given over the first 3 months. Doppler ultrasound and venographies were performed on days 1 and 90, respectively, or sooner in case of clinical presumption of thrombosis.

RESULTS

A total of 420 patients were randomized, and 407 were evaluable. Forty-two catheter-related deep vein thrombosis (DVT) occurred (10.3 %), 20 in those with no anticoagulation, 8 in those receiving warfarin, and 14 in those receiving LMWH. Nine additional non-related catheter deep vein thrombosis (CDVT) occurred. Anticoagulation significantly reduced the incidence of catheter-related DVT (p = 0.035) and catheter non-related DVT (p = 0.007), with no difference between warfarin and LMWH. Safety was good (3.4 % of attributable events) but compliance with randomized prophylaxis was lower than expected.

CONCLUSIONS

Prophylaxis showed a benefit regarding catheter-related and non-catheter-related DVT with no increase in serious side effects.

Central venous catheter care for the patient with cancer: American Society of Clinical Oncology clinical practice guideline

PURPOSE

To develop an evidence-based guideline on central venous catheter (CVC) care for patients with cancer that addresses catheter type, insertion site, and placement as well as prophylaxis and management of both catheter-related infection and thrombosis.

METHODS

A systematic search of MEDLINE and the Cochrane Library (1980 to July 2012) identified relevant articles published in English.

RESULTS

The overall quality of the randomized controlled trial evidence was rated as good. There is consistency among meta-analyses and guidelines compiled by other groups as well.

RECOMMENDATIONS

There is insufficient evidence to recommend one CVC type or insertion site; femoral catheterization should be avoided. CVC should be placed by well-trained providers, and the use of a CVC clinical care bundle is recommended. The use of antimicrobial/antiseptic-impregnated and/or heparin-impregnated CVCs is recommended to decrease the risk of catheter-related infections for short-term CVCs, particularly in high-risk groups; more research is needed. The prophylactic use of systemic antibiotics is not recommended before insertion. Data are not sufficient to recommend for or against routine use of antibiotic flush/lock therapy; more research is needed. Before starting antibiotic therapy, cultures should be obtained. Some life-threatening infections require immediate catheter removal, but most can be treated with antimicrobial therapy while the CVC remains in place. Routine flushing with saline is recommended. Prophylactic use of warfarin or low-molecular weight heparin is not recommended, although a tissue plasminogen activator (t-PA) is recommended to restore patency to occluded catheters. CVC removal is recommended when the catheter is no longer needed or if there is a radiologically confirmed thrombosis that worsens despite anticoagulation therapy.

International clinical practice guidelines for the treatment and prophylaxis of thrombosis associated with central venous catheters in patients with cancer

BACKGROUND

Although long-term indwelling central venous catheters (CVCs) may lead to pulmonary embolism (PE) and loss of the CVC, there is lack of consensus on management of CVC-related thrombosis (CRT) in cancer patients and heterogeneity in clinical practices worldwide.

OBJECTIVES

To establish common international Good Clinical Practices Guidelines (GCPG) for the management of CRT in cancer patients.

METHODS

An international working group of experts was set up to develop GCPG according to an evidence-based medicine approach, using the GRADE system.

RESULTS

For the treatment of established CRT in cancer patients, we found no prospective randomized studies, two non-randomized prospective studies and one retrospective study examining the efficacy and safety of low-molecular-weight heparin (LMWH) plus vitamin K antagonists (VKAs). One retrospective study evaluated the benefit of CVC removal and two small retrospective studies were on thrombolytic drugs. For the treatment of symptomatic CRT, anticoagulant treatment (AC) is recommended for a minimum of 3 months; in this setting, LMWHs are suggested. VKAs can also be used, in the absence of direct comparisons of these two types of anticoagulants in this setting [Guidance]. The CVC can be kept in place if it is functional, well-positioned and non-infected and there is good resolution under close surveillance; whether the CVC is kept or removed, no standard approach in terms of AC duration has been established [Guidance]. For the prophylaxis of CRT in cancer patients, we found six randomized studies investigating the efficacy and safety of VKA vs. placebo or no treatment, one on the efficacy and safety of unfractionnated heparin, six on the value of LMWH, one double-blind randomized and one non randomized study on thrombolytic drugs and six meta-analyses of AC and CVC thromboprophylaxis. Type of catheter (open-ended like the Hickman(®) catheter vs. closed-ended catheter with a valve like the Groshong(®) catheter), its position (above, below or at the junction of the superior vena cava and the right atrium) and method of placement may influence the onset of CRT on the basis of six retrospective trials, four prospective non-randomized trials, three randomized trials and one meta-analysis. In light of these data: use of AC for routine prophylaxis of CRT is not recommended [1A]; a CVC should be inserted on the right side, in the jugular vein, and distal extremity of the CVC should be located at the junction of the superior vena cava and the right atrium [1A].

CONCLUSION

Dissemination and implementation of these international GCPG for the prevention and treatment of CRT in cancer patients at each national level is a major public health priority, needing worldwide collaboration.

Catheter-related thrombosis: lifeline or a pain in the neck?

Central venous catheters (CVCs) are used extensively in cancer patients for the administration of therapy and phlebotomy. An important complication of CVCs is the development of catheter-related thrombosis (CRT), which becomes symptomatic in approximately 5% of the patients. Several factors, such as insertion location and position of the catheter tip, increase the risk of CRT. Prevention of CRT with systemic anticoagulant prophylaxis has largely been ineffective. In addition, the optimal diagnostic strategy and anticoagulant treatment are unclear due to the lack of well-designed studies. The most recent American College of Chest Physicians guidelines recommend (color) Doppler ultrasound more than venography as the initial diagnostic test in patients with suspected arm thrombosis. Only if the ultrasound is negative and clinical suspicion is high is further testing with D-dimer, serial ultrasound, or venography advocated. In case of CRT, removal of the catheter is not necessary if it is functional and needed for chemotherapy. Anticoagulant treatment of CRT consists of treatment with low-molecular-weight heparin (LMWH) followed by vitamin K antagonists for at least 3 months. Whether long-term treatment with LMWH is more effective than vitamin K antagonists in cancer patients with CRT is unknown, but LMWH may be advocated following the recommendations in lower limb thrombosis and cancer. In addition, the effect of new anticoagulants in CRT has not been studied.

Epidemiology and prevention of catheter-related thrombosis in patients with cancer

Central venous catheters are extensively used in patients with cancer to secure delivery of chemotherapy and facilitate phlebotomy. Unfortunately, considerable morbidity can result from early complications or late sequelae, ranging from arterial puncture, pneumothorax and bloodstream infections to catheter-related thrombosis (CRT). Contemporary studies have shown that the incidence of symptomatic CRT is ∼5%, whereas the incidence of asymptomatic CRT is higher, at 14-18%. The significance and mechanisms of catheter design, material, insertion location and technique, position of the catheter tip and other risk factors in contributing to the development of CRT are not well understood. Efforts to reduce thrombotic complications, involving flushing the catheter with heparinized solutions, the use of heparin-bonded catheters, and systemic anticoagulant prophylaxis, have been largely ineffective. More studies are needed to understand the pathophysiology of thrombotic complications, to help identify effective interventions to reduce this adverse outcome.

Anticoagulation for patients with cancer and central venous catheters

BACKGROUND

Central venous catheter (CVC) placement increases the risk of thrombosis in cancer patients. Thrombosis often necessitates the removal of the CVC, resulting in treatment delays and thrombosis related morbidity and mortality.

OBJECTIVES

To evaluate the efficacy and safety of anticoagulation in cancer patients with a CVC.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1 2010), MEDLINE (January 1966 to February 2010; accessed via OVID), EMBASE (January 1980 to February 2010; accessed via OVID) and ISI the Web of Science (1975 to February 2010). We handsearched conference proceedings, checked references of included studies and used the "related article" feature within PubMed.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing any dose of unfractionated heparin (UFH), low molecular weight heparin (LMWH), vitamin K antagonists (VKA), or fondaparinux to no intervention or placebo or comparing two different anticoagulants in cancer patients with a CVC.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each included study and resolved their disagreements by discussion.

MAIN RESULTS

Of 8187 identified citations, we included 12 RCTs enrolling 3611 patients and assessing either prophylactic dose heparin or low dose VKAs. Prophylactic dose heparin was not associated with a statistically significant effect on death (relative risk (RR) = 0.85; 95% confidence interval (CI): 0.53 to 1.37), symptomatic deep venous thrombosis (DVT) (RR = 0.54; 95% CI: 0.28 to 1.05) asymptomatic DVT (RR = 0.81; 95% CI: 0.64 to 1.02), major bleeding (RR = 0.68; 95% CI: 0.10 to 4.78), thrombocytopenia (RR = 0.85; 95% CI: 0.49 to 1.46), or infection (RR = 0.91; 95% CI: 0.49 to 1.68). Similarly, low dose VKAs were not associated with a statistically significant effect on death (RR = 0.97; 95% CI: 0.82 to 1.15), symptomatic DVT (RR = 0.63; 95% CI: 0.35 to 1.11) or major bleeding (RR = 6.93; 95% CI: 0.86 to 56.08). However, they were associated with a statistically significant reduction in asymptomatic DVT (RR = 0.42; 95% CI: 0.28 to 0.61). Studies comparing heparin to VKA found no effects on any of the outcomes of interest.

AUTHORS' CONCLUSIONS

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.

Anticoagulation for patients with cancer and central venous catheters

BACKGROUND

Central venous catheter (CVC) placement increases the risk of thrombosis in cancer patients. Thrombosis often necessitates the removal of the CVC, resulting in treatment delays and thrombosis related morbidity and mortality.

OBJECTIVES

To evaluate the efficacy and safety of anticoagulation in cancer patients with a CVC.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1 2010), MEDLINE (January 1966 to February 2010; accessed via OVID), EMBASE (January 1980 to February 2010; accessed via OVID) and ISI the Web of Science (1975 to February 2010). We handsearched conference proceedings, checked references of included studies and used the "related article" feature within PubMed.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing any dose of unfractionated heparin (UFH), low molecular weight heparin (LMWH), vitamin K antagonists (VKA), or fondaparinux to no intervention or placebo or comparing two different anticoagulants in cancer patients with a CVC.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each included study and resolved their disagreements by discussion.

MAIN RESULTS

Of 8187 identified citations, we included 12 RCTs enrolling 3611 patients and assessing either prophylactic dose heparin or low dose VKAs. Prophylactic dose heparin was not associated with a statistically significant effect on death (relative risk (RR) = 0.85; 95% confidence interval (CI): 0.53 to 1.37), symptomatic deep venous thrombosis (DVT) (RR = 0.54; 95% CI: 0.28 to 1.05) asymptomatic DVT (RR = 0.81; 95% CI: 0.64 to 1.02), major bleeding (RR = 0.68; 95% CI: 0.10 to 4.78), thrombocytopenia (RR = 0.85; 95% CI: 0.49 to 1.46), or infection (RR = 0.91; 95% CI: 0.49 to 1.68). Similarly, low dose VKAs were not associated with a statistically significant effect on death (RR = 0.97; 95% CI: 0.82 to 1.15), symptomatic DVT (RR = 0.63; 95% CI: 0.35 to 1.11) or major bleeding (RR = 6.93; 95% CI: 0.86 to 56.08). However, they were associated with a statistically significant reduction in asymptomatic DVT (RR = 0.42; 95% CI: 0.28 to 0.61). Studies comparing heparin to VKA found no effects on any of the outcomes of interest.

AUTHORS' CONCLUSIONS

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.

Risk factors for catheter-related thrombosis (CRT) in cancer patients: a patient-level data (IPD) meta-analysis of clinical trials and prospective studies

BACKGROUND

Knowledge of independent, baseline risk factors for catheter-related thrombosis (CRT) may help select adult cancer patients who are at high risk to receive thromboprophylaxis.

OBJECTIVES

We conducted a meta-analysis of individual patient-level data to identify these baseline risk factors.

PATIENTS/METHODS

MEDLINE, EMBASE, CINAHL, CENTRAL, DARE and the Grey literature databases were searched in all languages from 1995 to 2008. Prospective studies and randomized controlled trials (RCTs) were eligible. Studies were included if original patient-level data were provided by the investigators and if CRT was objectively confirmed with valid imaging. Multivariate logistic regression analysis of 17 prespecified baseline characteristics was conducted. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated.

RESULTS

A total sample of 5636 subjects from five RCTs and seven prospective studies was included in the analysis. Among these subjects, 425 CRT events were observed. In multivariate logistic regression, the use of implanted ports as compared with peripherally implanted central venous catheters (PICCs), decreased CRT risk (OR, 0.43; 95% CI, 0.23-0.80), whereas past history of deep vein thrombosis (DVT) (OR, 2.03; 95% CI, 1.05-3.92), subclavian venipuncture insertion technique (OR, 2.16; 95% CI, 1.07-4.34) and improper catheter tip location (OR, 1.92; 95% CI, 1.22-3.02), increased CRT risk.

CONCLUSIONS

CRT risk is increased with use of PICCs, previous history of DVT, subclavian venipuncture insertion technique and improper positioning of the catheter tip. These factors may be useful for risk stratifying patients to select those for thromboprophylaxis. Prospective studies are needed to validate these findings.

Venous thromboembolism in the patient with cancer: focus on burden of disease and benefits of thromboprophylaxis

Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in patients with cancer. The risk of VTE varies over the natural history of cancer, with the highest risk occurring during hospitalization and after disease recurrence. Patient and disease characteristics are associated with further increased risk of VTE in this setting. Specific factors include cancer type (eg, pancreatic cancer, brain cancer, lymphoma) and the presence of metastatic disease at the time of diagnosis. VTE is a significant predictor of increased mortality during the first year among all types and stages of cancer, with metastatic disease reported to be the strongest predictor of mortality. VTE is also associated with early death in ambulatory patients with cancer. These data highlight the need for close monitoring, prompt treatment, and appropriate preventive strategies for VTE in patients with cancer. The American Society of Clinical Oncology and the National Comprehensive Cancer Network have issued guidelines regarding the prophylaxis and treatment of patients with cancer. This review summarizes the impact of VTE on patients with cancer, the effects of VTE on clinical outcomes, the importance of thromboprophylaxis in this population, relevant ongoing clinical trials examining the prevention of VTE, and new pharmacologic treatment options.