Lack of efficacy of twice-weekly urokinase in the prevention of complications associated with Hickman catheters: a multicentre randomised comparison of urokinase versus heparin

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.

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.

Urokinase Lock or Flush Solution for Prevention of Bloodstream Infections Associated with Central Venous Catheters for Chemotherapy: A Meta-Analysis of Prospective Randomized Trials

Background

Intravascular devices (IVDs) carry significant risk of device-associated bloodstream infection (BSI). Catheter thrombosis increases the likelihood of microbial colonization of the catheter and BSI. Urokinase has been studied for the prevention of BSI associated with IVDs. We undertook a systematic review to determine the efficacy of urokinase-heparin lock or flush solution compared with heparin alone in preventing IVD-associated BSI.

Methods

Computerized databases were searched for relevant publications in English from January 1966 to 1 January 2007. We identified randomized controlled trials comparing a urokinase-heparin lock or flush solution with heparin alone for prevention of BSI associated with long-term IVDs. Summary effect sizes were calculated with assessment of heterogeneity.

Results

Five randomized, controlled trials involving a total of 991 patients being treated with IVDs met the inclusion criteria; all five studies were conducted among patients with cancer; three of these studies were undertaken in children and two in adults. The summary risk ratio with a urokinase-heparin lock solution for IVD-associated BSI was 0.77 (95% confidence interval [CI], 0.60–0.98; p=0.01). Results of the test for heterogeneity were not statistically significant (p=0.53).

Conclusions

Use of a urokinase lock solution in high-risk patient populations being treated with long-term central IVDs may reduce the risk of BSI. However, there are few randomized trials and methodologic limitations of these preclude more robust recommendations regarding the use of urokinase to prevent BSI. Further adequately powered studies should seek to evaluate the efficacy of urokinase and optimize dosage and instillation regimen.

Flushing and Locking of Venous Catheters: Available Evidence and Evidence Deficit

Flushing and locking of intravenous catheters are thought to be essential in the prevention of occlusion. The clinical sign of an occlusion is catheter malfunction and flushing is strongly recommended to ensure a well-functioning catheter. Therefore fluid dynamics, flushing techniques, and sufficient flushing volumes are important matters in adequate flushing in all catheter types. If a catheter is not in use, it is locked. For years, it has been thought that the catheter has to be filled with an anticoagulant to prevent catheter occlusion. Heparin has played a key role in locking venous catheters. However, the high number of risks associated with heparin forces us to look for alternatives. A long time ago, 0.9% sodium chloride was already introduced as locking solution in peripheral cannulas. More recently, a 0.9% sodium chloride lock has also been investigated in other types of catheters. Thrombolytic agents have also been studied as a locking solution because their antithrombotic effect was suggested as superior to heparin. Other catheter lock solutions focus on the anti-infective properties of the locks such as antibiotics and chelating agents. Still, the most effective locking solution will depend on the catheter type and the patient's condition.

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.

Flushing the central venous catheter: is heparin necessary?

PURPOSE

The aim of this systematic review was to assess the efficacy of heparin flushing in the lock of central venous catheters.

METHODS

We searched MEDLINE and CINAHL databases. Eligible studies were randomized controlled trials evaluating the use of heparin versus normal saline or other solution in the flushing of central catheter among adult patients. No language restrictions were applied. Two reviewers independently screened titles and abstracts in order to identify relevant publications. The same two reviewers retrieved and evaluated full texts. Parameter estimates regarding catheter occlusion were pooled using network meta-analysis with Bayesian hierarchical modeling.

RESULTS

We identified 462 references. Eight studies were included. There was no evidence that heparin was more effective than normal saline in reducing occlusions. It was unclear whether urokinase and lepirudin were more effective than heparin in reducing occlusions. Vitamin C solution does not appear to prolong catheter patency.

CONCLUSIONS

There is no evidence of a different effectiveness between heparin flushing and normal saline or other solutions in reducing catheter occlusions. Due to the little and inconclusive evidence available in this field, further studies might be necessary.

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.

Thrombotic obstruction of the central venous catheter in patients undergoing hematopoietic stem cell transplantation

This is an integrative literature review with the aim of summarizing the prevention measures and treatment of thrombotic obstruction of long-term semi-implanted central venous catheters, in patients undergoing hematopoietic stem cell transplantation. The sample consisted of seven studies, being two randomized controlled clinical trials, three cohort studies and two case series. Regarding the prevention measures, one single study demonstrated effectiveness, which was a cohort study on the oral use of warfarin. In relation to the treatment measures, three studies evidenced effectiveness, one highlighted the efficacy of streptokinase or urokinase, one demonstrated the benefit of using low-molecular-weight heparin and the other treated the obstruction with heparin or urokinase. Catheter patency research shows a restricted evolution that does not follow the evolution of transplantations, mainly regarding nursing care.

Thrombolytic therapy for central venous catheter occlusion

BACKGROUND

Long-term central venous catheters have improved the quality of care for patients with chronic illnesses, but are complicated by obstructions which can result in delay of treatment or catheter removal.

DESIGN AND METHODS

This paper reviews thrombolytic treatment for catheter obstruction. Literature from Medline searches using the terms "central venous catheter", "central venous access device" OR "central venous line" associated with the terms "obstruction", "occlusion" OR "thrombolytic" was reviewed. Efficacy of thrombolytic therapy, central venous catheter clearance rates and time to clearance were assessed.

RESULTS

Alteplase, one of the current therapies, clears 52% of obstructed catheters within 30 min with 86% overall clearance (after 2 doses, when necessary). However, newer medications may have higher efficacy or shorter time to clearance. Reteplase cleared 67-74% within 30-40 min and 95% of catheters overall. Occlusions were resolved in 70 and 83% of patients with one and 2 doses of tenecteplase, respectively. Recombinant urokinase cleared 60% of catheters at 30 min and 73% overall. Alfimeprase demonstrated rapid catheter clearance with resolution in 40% of subjects within 5 min, 60% within 30 min, and 80% within 2 h. Additionally, urokinase prophylaxis decreased the incidence of catheter occlusions from 16-68% in the control group to 4-23% in the treatment group; in some studies, rates of catheter infections were also decreased in the urokinase group.

CONCLUSIONS

Thrombolytic agents successfully clear central venous catheter occlusions in most cases. Newer agents may act more rapidly and effectively than currently utilized therapies, but randomized studies with direct comparisons of these agents are needed to determine optimal management for catheter obstruction.

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.

Heparin flushing and other interventions to maintain patency of central venous catheters: a systematic review

AIM

This paper is a report of a review to assess clinical studies comparing the effectiveness of different means of maintaining central venous catheter patency.

BACKGROUND

Flushing with heparin is a routine part of central venous catheter maintenance, but it presents risks, including heparin-induced thrombocytopenia. Other techniques used to prevent occlusion of catheters include saline flushes, heparin-bonded catheters and pressure caps.

DATA SOURCES

A search was conducted using the MEDLINE, CINAHL, EMBASE, Cochrane, National Guideline Clearinghouse and University Healthsystem Consortium databases.

METHODS

A systematic review of effectiveness was conducted, using GRADE criteria to assess the strength of evidence for each intervention. The review period covered 1982 or earlier to January 2008.

RESULTS

There is weak evidence that heparin flushing reduces occlusion of catheters, but no evidence that it reduces bloodstream infections. Results from clinical trials of pressure caps are inconsistent regarding their ability to maintain catheter patency, but provide moderate evidence that at least some varieties of caps are associated with increased bloodstream infections.

CONCLUSION

The evidence base on heparin flushing and other interventions to prevent catheter occlusion is small, and published studies are of low quality. There is insufficient evidence on which to conclude that flushing catheters with heparin is more effective than flushing with saline solution.

Prolonged interval in prophylactic heparin flushing for maintenance of subcutaneous implanted port care in patients with cancer

The long-term use of subcutaneous implanted ports for chemotherapy in cancer patients has been associated with the occurrence of thrombosis and infection. In this study, we compared the safety and efficacy of administration of 1000 U of heparin flushes in prolonged interval (every 6 weeks) with standard dose and schedule (500 U every 4 weeks) for port-related infections and thrombosis during periods of non-use. Data were collected retrospectively from patients treated for various cancer types (matched as 2:1 for age, gender, stage of the disease). Patients who had diseases that could cause thrombosis or bleeding in their past medical history, or were taking oral anticoagulants, or had contraindications for heparin usage were excluded. After completing their chemotherapy, 59 patients received prolonged interval, while 30 patients received standard schedule. All patients were followed for at least 1 year. No clinically documented port-related infection or thrombosis has been found in both groups. Also, none of the devices was removed during this time. Prophylactic flushing of central venous ports with 1000 U of heparin in every 6 weeks might be a safe, easy, cheaper, comfortable and effective alternative to standard dose and schedule for preventing thrombosis and infections.

Review and update of the use of urokinase in the prevention and management of CVAD-related complications in pediatric oncology patients

Pediatric oncologists from Germany systematically reviewed the literature, considering the use of urokinase in pediatric oncology patients published since 1998 and came to the following conclusions. The use of urokinase to prevent central venous access device (CVAD)-related infections in pediatric cancer patients represents an evidence-based approach, at least in external, tunneled catheters (eg, Hickman, Broviac). The effectiveness of urokinase prophylaxis in decreasing infections and thrombotic events is probably related not only to the concentration and timing of the urokinase intervention but also to the type of CVAD, and perhaps to the intensity of the concomitant chemotherapy program. Urokinase can safely and effectively be used on CVADs with malfunctioning or intraluminal occlusion in a dose of 5000 IU/mL or as salvage 3-hour infusion with 1000 IU/kg/hour. Hitherto, adjuvant treatment with urokinase in the management of CVADs with intraluminal infection still relies on case reports and small case series. In this field, a randomized controlled study is necessary.

Prevention of Coagulase-Negative Staphylococcal Central Venous Catheter–Related Infection Using Urokinase Rinses: A Randomized Double-Blind Controlled Trial in Patients With Hematologic Malignancies

Purpose

Fibrin deposition at the intraluminal surface of the indwelling part of the central venous catheter (CVC) surface increases the risk of CVC-related coagulase-negative staphylococci (CoNS) infection. Therefore, repetitive enzymatic dissolution of fibrin by urokinase might reduce the risk of CVC-related infection. We undertook this study to investigate whether three times weekly urokinase rinsing of CVC reduces the incidence or severity of CVC-related infections by CoNS in patients undergoing intensive cytotoxic treatment for hematologic malignancies.

Patients and Methods

In a double-blind setting, all consecutive patients with a CVC were randomly allocated to receive either urokinase rinses (5 mL of 5,000 U/mL) or placebo (saline), both three times weekly.

Results

The percentage of patients with at least one positive culture with CoNS was lower in patients receiving urokinase compared with patients receiving placebo (26% v 42%, respectively; relative risk [RR] = 0.61; 95% CI, 0.39 to 0.94). Major CVC-related CoNS infection occurred less frequently in patients receiving urokinase versus placebo (1.2% v 14.1%, respectively; RR = 0.09; 95% CI, 0.01 to 0.50). Secondary complications, including CVC-related thrombosis, were observed less frequently in the urokinase group compared with the placebo group (1.3% v 9.0%, respectively; RR = 0.14; 95% CI, 0.02 to 0.82). No severe bleeding complications attributable to urokinase were observed.

Conclusion

Three times weekly urokinase rinsing reduces the incidence of CVC-related CoNS infection in patients treated with intensive cytotoxic therapy for hematologic malignancies, with acceptable safety.

Anticoagulation for thrombosis prophylaxis in cancer patients with 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 reducing venous thromboembolic (VTE) events in cancer patients with CVC.

SEARCH STRATEGY

A comprehensive search for studies of anticoagulation in cancer patients up to January 2006 was conducted in the following databases: The Cochrane Central Register of Controlled Trials ( CENTRAL), MEDLINE, EMBASE and ISI the Web of Science.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Data was extracted on methodological quality, patients, interventions and outcomes including all cause mortality (primary outcome), premature CVC removal, catheter-related infections, CVC site and non CVC site deep venous thrombosis (DVT), pulmonary embolism (PE), major and minor bleeding and thrombocytopenia.

MAIN RESULTS

Of 3986 identified citations nine RCTs were included in the meta-analysis including one published as an abstract and one focusing on paediatric patients not included in the meta-analysis. None of these RCTs tested fondaparinux or ximelagatran. The use of heparin in cancer patients with CVC was associated with a trend towards a reduction in symptomatic DVT (Relative Risk (RR) = 0.43; 95% Confidence Interval (CI): 0.18 to 1.06), but the data did not show any statistically significant effect on mortality (RR = 0.74; 95% CI: 0.40 to 1.36), infection (RR = 0.91; 95% CI: 0.36 to 2.28), major bleeding (RR = 0.68; 95% CI: 0.10 to 4.78) or thrombocytopenia (RR = 0.85; 95% CI: 0.49 to 1.46). The effect warfarin on symptomatic DVT was not statistically significant (RR = 0.62; 95% CI: 0.30 to 1.27). When studies assessing different types of anticoagulants were pooled, symptomatic DVT rates were significantly reduced (RR = 0.56; 95% CI: 0.34 to 0.92).

AUTHORS' CONCLUSIONS

Cancer patients with CVC considering anticoagulation, should consider the possible benefit of reduced incidence of thromboembolic complications with the burden and harms of anticoagulation. Future studies should be adequately powered and evaluate the effects of newer anticoagulants such as fondaparinux and ximelagatran in cancer patients with CVC.

Central venous line-related thrombosis in children

Central venous lines are used in critically ill children and in children with chronic conditions for the administration of intravenous therapy, such as fluids, medications, total parenteral nutrition and blood products. Although the use of central venous lines has greatly improved the quality of care in these children, these catheters may cause serious mechanical, infectious and thrombotic complications. The reported frequency of catheter thrombosis in children is low as 5% in studies including only symptomatic cases and high as 50% in studies where patients are systematically screened for catheter-related thrombosis. The risk factors for catheter-related thrombosis in children are associated with the methods used for catheter insertion and with individual patient characteristics, underlying diagnosis and treatment. The management of catheter-related thrombosis is largely dependent on the requirement of the catheter. If no longer required or nonfunctioning the catheter should be removed. If access is still required and the catheter is functioning, treatment with anticoagulation is recommended in the absence of contraindications. The management of radiographically detected asymptomatic thrombosis in children is less clear. Clinical studies of prophylaxis for catheter-related thrombosis are inconclusive and no definitive recommendations for prophylaxis in adults or in children with central venous thrombosis can be made. Properly designed studies are needed to assess the role of prophylactic anticoagulation for preventing catheter-related thrombosis.

Leading Change

Central venous access is essential for patients undergoing autologous hematopoietic stem cell transplantation (ASCT). Traditionally, tunneled silastic catheters have been inserted in these patients. However, changes in resource allocation, resulting in reduced surgery and surgeon time and decreasing toxicity associated with ASCT, have caused changes in venous access needs and options. This led the advanced practice nurse in the transplant program to evaluate other central access devices, which resulted in the introduction of peripherally inserted central catheters (PICCs) for this patient population. This study reports the results of a retrospective analysis comparing efficacy and complication profiles between 50 patients with the traditional Hickman catheter and 70 patients with PICCs.

Thrombosis in infants and children

During the last decade much progress has been made toward better understanding of the underlying reasons causing thromboembolism in children. A considerable number of acquired and hereditary thrombotic risk factors have been identified which may also have an impact on therapeutic decisions and prognosis concerning outcome and the risk of a second event. However, indications for therapeutic interventions, such as thrombolysis and prophylactic anticoagulation with respect to the different clinical conditions and their combination with other risk factors, are not yet well defined. The following article describes the causes, clinical presentation and management of thrombosis in neonates, infants and older children, focusing on the clinically most relevant conditions.

Prophylactic urokinase in the management of long-term venous access devices in children: a Children's Oncology Group study

PURPOSE

Infection and thrombosis are serious complications of long-term vascular access devices in children undergoing chemotherapy. Since routine fibrinolytic therapy may decrease these complications, the purpose of this study was to compare the efficacy of an every-2-week administration of urokinase with standard heparin flushes in reducing the incidence of device-related infections and occlusions.

MATERIALS AND METHODS

This study was a prospective, randomized phase III multicenter trial conducted by the Children's Cancer Group, in which patients with implantable ports or tunneled catheters received either urokinase or heparin every 2 weeks for 12 months. Study end points were time to first occlusion or time to first device-related infection.

RESULTS

Five hundred seventy-seven patients from 29 institutions were enrolled, of whom 51% had external catheters and 49% had ports. Urokinase administration resulted in fewer occlusive events than heparin (23% v 31%; P =.02), a longer time to first occlusive event (log-rank analysis, P =.006), and a 1.6-fold difference in the rate of occlusive events (Poisson regression, P =.003). Similar results were noted when comparing ports and tunneled catheters. The urokinase group also had a 1.4-fold difference in the rate of infection (Poisson regression, P =.05) and longer time to first infection (log-rank, P =.07), but the difference was significant only in tunneled catheters.

CONCLUSION

Urokinase administration every 2 weeks significantly affects the rate of occlusive events in ports and tunneled catheters and of infectious events in external catheters compared with heparin administration.

Prophylaxis of port system-associated thromboses in advanced oncology patients using heparin flushing

PURPOSE

Thromboses occur in connection with the use of venous port systems. Valid data on the instillation of heparin-based solutions in the lumen of the port system are lacking.

METHODS

One hundred and seventy-three patients with malignancy from 19 centres who had participated in an observation study of subcutaneous thromboprophylaxis with dalteparin-Na (Fragmin P/-Forte) were analysed with a view to flushing the port systems and investigating any related influence on the occurrence of catheter-associated thromboses.

RESULTS

All catheter-associated thromboses were seen in centres which used either no UFH, or UFH concentrations of up to 250 IU/ml (8/108; 7.4%). The rate of thrombosis rose to 10% (6/60) if no high-risk dose of dalteparin was applied subcutaneously. On the other hand, the rate of catheter-associated thromboses under the high-risk dose of dalteparin and/or a more highly concentrated instillation fluid, at 0.9% (1/113), was much lower. One haemorrhage from gastric ulcer occurred under the highest UFH concentration in the instillation fluid (2,500 IU UFH/ml).

CONCLUSION

The results indicate that a concentration between 500 IU UFH/ml and 1,000 IU UFH/ml in the instillation solution, at the same time as high-risk prophylaxis with subcutaneous dalteparin for prevention of catheter-associated thromboses, is effective in patients with manifest tumour disease. The instillation of LMWH-based solutions at a concentration of approx 500 anti-Xa units/ml should be discussed as a pending issue.