Efficacy and safety of reteplase for central venous catheter occlusion in patients with cancer

A Retrospective Analysis of Venographic Images of a Central Venous Port without Blood Return and Its Usable Period

Objective In routine practice, central venous ports without blood return (CVPWBRs) are common. However, very few studies have reported on the viable period of CVPWBR use. We therefore investigated this period by retrospectively analyzing the venographic images of CVPWBRs. Methods We examined patients' venography through the CVPs at the point when they became CVPWBRs for the first time and analyzed the reasons for becoming CVPWBRs. For patients with minor complications of CVPs or normal venographic findings, we used the Kaplan-Meier method to evaluate the period for which such CVPWBRs could be used. Patients Eighty-four patients with malignancy whose CVPs became CVPWBRs for the first time between July 31, 2015, and March 12, 2020, were included. Results Nine (10.7%) patients had major complications that made the CVPs unusable. Thirty-three (39.3%) patients had minor complications, and the remaining 42 (50.0%) had normal venographic findings. For the 75 patients with minor complications or normal venographic findings who continued to use their CVPWBRs, the Kaplan-Meier method estimated that 25% of complications that might make it unusable would occur within 1,273 days. Conclusion There are two learning points in our study. First, venography is needed when the CVP becomes a CVPWBR for the first time due to the high risk, and second, CVPWBRs can be used for a relatively long period in patients without major complications. It is necessary to develop an appropriate follow-up management method for CVPWBRs in prospective studies.

Effectiveness of mechanical recanalization for intraluminal occlusion of totally implantable venous access ports

PURPOSE

To evaluate if the mechanical injection of saline is effective in restoring patency of a totally implantable venous access port (TIVAP) with an intraluminal occlusion.

MATERIALS AND METHODS

From January 2017 to June 2019, 64 cases of dysfunction of a TIVAP were referred to interventional radiology. Among these, 16 cases showed normal function of the TIVAP, 19 cases the showed the appearance of a fibroblastic sheath, and 29 cases showed intraluminal occlusion. Mechanical recanalization was performed for intraluminal occlusion of the TIVAP with an indeflator and a 20G non-coring needle. Linograms were performed in all recanalized cases. The success or failure of recanalization and the pressure of the indeflator were recorded. Linograms were evaluated for breakage or migration of catheters. Medical records were retrospectively reviewed.

RESULTS

Among the 29 intraluminal occlusion cases, 24 cases (82.7%) were recanalized by mechanical recanalization via an indeflator. The pressure of the indeflator ranged from 29 to 220 psi (median: 118 psi). Linograms revealed breakage of the catheter of the TIVAP in two failed cases. The median interval from implantation to dysfunction was 405 days (range: 43-1723 days). The median interval from last use to dysfunction was 8 days (mean: 15.4 days; range: 1-119 days). The median re-occlusion free period after successful mechanical recanalization was 100.5 days (range: 6-859 days).

CONCLUSION

In the absence of an available thrombolytic agent, mechanical injection of saline was a tolerable alternative method for restoring occluded catheters and sustaining the function of catheters. Because breakage of the catheter can occur during mechanical recanalization of a TIVAP, a linogram should follow the procedure.

Interventions to obstructive long-term central venous catheter in cancer patients: a meta-analysis

PURPOSE

The aim of this systematic review was to identify the interventions used to treat obstructive events, whether thrombotic or non-thrombotic, in long-term central venous catheters (LT-CVC) in cancer patients.

METHODS

This review included clinical trials and observational studies reporting the drugs used to treat obstructive catheter events in cancer patients. The authors developed specific search strategies for CINAHL, Cochrane CENTRAL, LILACS, PubMed, Scopus, Web of Science, Google Scholar, Open Grey, and ProQuest. The authors evaluated methodological quality of included studies using criteria from Cochrane's Collaboration Tool and the Methodological Index for non-randomized studies (MINORS). The quality of evidence was analyzed by using GRADE's software.

RESULTS

More than 9000 articles were found across the databases. After duplicates removed, the studies were selected in 2 phases. After that, only 15 studies were included. The drugs used to restoration of catheter function were urokinase (53.3%), alteplase (20%), tenecteplase (13.3%), reteplase (6.7%), recombinant urokinase (6.7%), and staphylokinase (6.7%). The results of meta-analysis of 14 studies showed an overall restoration rate of ~ 84%. The drug type meta-analysis demonstrates a success rate of ~ 84%, ~ 92%, and ~ 84% for urokinase, alteplase, and tenecteplase groups, respectively. The main methodological problem in included articles concerns the sample. The quality of evidence ranged from very low to high.

CONCLUSION

The most common interventions used to treat thrombotic catheter occlusion in cancer patients were urokinase and alteplase. No evidence was found about the treatment for non-thrombotic occlusion, thus elucidating an important gap to be investigated.

Mechanical recanalization for clot occlusion of venous access ports: experimental study using ports with clot occlusion

PURPOSE

To test the hypothesis that mechanical injection of saline is safe and effective in restoring patency of totally implantable venous access ports (TIVAPs) with clot occlusion. We devised an experimental port model for the evaluation of mechanical TIVAP recanalization prior to its clinical application.

MATERIALS AND METHODS

The clot TIVAP occlusion model was constructed by filling the catheter with swine blood and incubating it at 37.5°C. The model was incubated for different lengths of time ranging from 1 day to 7 days. Each incubation time point included 20 ports. Total catheter occlusion of the TIVAPs was assessed with a 10-mL saline syringe equipped with a non-coring needle. Occlusion was defined as no passage of saline through the catheter when it was aspirated and infused gently with the 10-mL saline syringe. Pressure was evaluated during recanalization with an indeflator. Histological examination was performed on the clot obtained during recanalization.

RESULTS

Among the 140 total experimental ports, 65 occlusions (46.4%) were detected. Of these 65 occlusions, 56 (86.1%) were recanalized by mechanical saline pressure via the indeflator. The indeflator pressure ranged from 29 pound per square-inch (psi) to 265 psi at mechanical catheter recanalization (mean: 110 psi). Histologically, all specimens from the model ports exhibited a similar appearance; specifically, erythrocytes, cells, and fibrin were evenly scattered throughout the clot.

CONCLUSIONS

Our data indicate that it is feasible to generate a TIVAP clot occlusion model with swine blood. Moreover, mechanical recanalization was suitable for resolving occluded catheters without thrombolytic agents.

Interventions for restoring patency of occluded central venous catheter lumens

BACKGROUND

Central venous catheters (CVCs) facilitate the administration of intravenous drugs, fluids, blood products and parenteral nutrition to patients with either chronic disease or critical illness. Despite a pivotal role within medical management, a common complication associated with CVC use is occlusion of the CVC lumen(s). CVC occlusion can interrupt and cause serious delays in administration of treatment interventions.

OBJECTIVES

The primary objective of this review was to assess the efficacy and safety of different interventions used to restore patency of occluded CVC lumens, in adults and children.

SEARCH METHODS

We identified trials by searching the Cochrane Central Register of Clinical Trials (CENTRAL) (The Cochrane Library 2011, Issue 9); OvidSP MEDLINE (1950 to September 2011); OvidSP EMBASE (1980 to September 2011) and NHS Evidence CINAHL (1982 to September 2011). We also searched clinical trial registers, handsearched reference lists, contacted pharmaceutical companies and authors of publications that met the inclusion criteria to identify trials.

SELECTION CRITERIA

We selected randomized controlled trials which investigated the efficacy of an intervention (chemical, surgical or drug) used to restore patency to an occluded CVC lumen, in either adults or children.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed those studies that met the inclusion criteria for quality and extracted the relevant data using a standardized form.

MAIN RESULTS

No studies were found that investigated the efficacy and safety of either chemical or surgical interventions.Seven studies (eight papers) with a total of 632 participants were identified from the search. They investigated different comparisons, strengths of thrombolytic or anticoagulant drug interventions for treating CVC lumen occlusion thought to be caused by a thrombus.There was low quality evidence from a meta-analysis of two studies suggesting that urokinase (various strengths) was more effective than placebo for restoring patency to occluded CVC lumens in adults and children with underlying medical conditions (relative risk (RR) 2.09, 95% confidence interval (CI) 1.47 to 2.95), with a number needed to treat of 4 (95% CI 2 to 8). There was insufficient evidence to draw conclusions on the safety of urokinase.The overall quality of the evidence provided by these studies was low to very low due to one or more domains being assessed as either at 'unclear risk of bias' or 'high risk of bias'. Furthermore, the total number of participants in these studies was small and consequently may lead to spurious results.

AUTHORS' CONCLUSIONS

There is inadequate evidence to draw strong conclusions on the efficacy or safety of the drug interventions included in this review. There is some low quality evidence from a meta-analysis of two studies investigating urokinase (various strengths) and some very low evidence from two single studies investigating alteplase 2 mg/2 mL that suggest that these two drug interventions may be effective in treating withdrawal or total occlusion of CVC lumens caused by thrombosis. Further high quality, sufficiently powered research is still required to look at the efficacy and safety of urokinase, alteplase and other chemical, surgical and drug interventions for treating CVC lumen occlusion. Research studies which exclusively include child participants are especially warranted.

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.

Clinical utility of novel agents in the treatment of central venous catheter occlusion

Central venous catheter (CVC) occlusion occurs frequently and remains a significant clinical problem in patients with cancer receiving infusional or intravenous chemotherapy. Thrombotic occlusions frequently limit the benefits of potentially curable cytotoxic agents by interrupting the delivery of infusion of chemotherapy, intravenous medication, nutritional support, and blood products, as well as the frequent acquisition of venous blood samples for laboratory testing. Urokinase has been used as a thrombolytic agent for dysfunctional occluded CVCs, but the alterations in manufacturing practice prompted the Food and Drug Administration to suspend further production of urokinase in 1999. Although streptokinase had a potential as a thrombolytic agent in place of urokinase, the risk of life-threatening anaphylaxis associated with this agent prompted researchers to look for newer agents to dissolve CVC occlusions. Several novel thrombolytic agents are currently being evaluated as a potential treatment for patients with CVC occlusions and acute or chronic peripheral arterial occlusions. Alfimeprase, a recombinant fibrinolytic zinc metalloprotease, has shown promising clinical utility in blood clot lysis in patients with CVC occlusions and peripheral arterial occlusions. Based on the encouraging data, alfimeprase has received orphan drug designation from the Food and Drug Administration and the Committee for Orphan Medicinal Products of the European Medicines Agency for the evaluation of acute peripheral arterial occlusions as a potential indication. Other novel thrombolytic agents such as alteplase and reteplase are undergoing clinical evaluation for their utility in restoring the function of occluded CVCs. The clinical potency of these novel agents and their ongoing clinical trials are discussed briefly herein.

[Urokinase in the management of occluded PICC lines]

PURPOSE

To determine the efficacy and safety of urokinase in the management of occluded PICC lines.

MATERIALS AND METHODS

A total of 587 PICC lines were placed over an 11 month period. During this period, 28 PICC lines (4.8%) became occluded: 12 occluded PICC lines were successfully managed by simple flushing with normal saline while 16 PICC lines were thrombolyzed with urokinase.

RESULTS

After urokinase, 93.8% (15/16) of occluded PICC lines were completely patent. A single infusion of urokinase, 20,000 IU over 30 minutes, was used in all cases. No secondary occlusion or complication was noted after urokinase.

CONCLUSION

Urokinase is effective and safe to restore patency to occluded PICC lines. The procedure is simple, and could be performed at the bedside by nursing staff after medical prescription. It is an alternative to over the wire PICC line exchange, that could reduce the risk of complication related to manipulations, patient discomfort and cost.

Treatment of venous thromboembolism in patients with cancer: Guidelines of the Italian Society for Haemostasis and Thrombosis (SISET)

BACKGROUND

The treatment of venous thromboembolism (VTE) in cancer patients remains controversial.

PURPOSE

The Italian Society for Thrombosis and Haemostasis (SISET) commissioned a project to develop clinical practice guidelines for the therapy of VTE in patients with malignancies.

METHODS

Key questions about the treatment of VTE in patients with malignancies were formulated by a multidisciplinary working group consisting of experts in clinical medicine and research. After a systematic review and discussion of the literature, recommendations were formulated and graded according to the supporting evidence. For those questions for which the literature search did not yield any definitive answer (absence of evidence evidence of low quality, and contradictory evidence), a formal consensus method was used to issue clinical recommendations.

RESULTS

The results of the available literature on VTE treatment in cancer patients were reviewed and clinical recommendations were drafted.

CONCLUSION

We describe the results of a systematic literature review and an explicit approach to consensus techniques which resulted in recommendations for the key therapeutic issues in cancer patients with VTE.

Management of occlusion and thrombosis associated with long-term indwelling central venous catheters

Long-term central venous catheters (CVCs) are important instruments in the care of patients with chronic illnesses, but catheter occlusions and catheter-related thromboses are common complications that can result from their use. In this Review, we summarise management of these complications. Mechanical CVC occlusions need cause-specific treatment, whereas thrombotic occlusions usually resolve with thrombolytic treatment, such as alteplase. Prophylaxis with thrombolytic flushes might prevent CVC infections and catheter-related thromboses, but confirmatory studies and cost-effectiveness analysis of this approach are needed. Risk factors for catheter-related thromboses include previous catheter infections, malposition of the catheter tip, and prothrombotic states. Catheter-related thromboses can lead to catheter infection, pulmonary embolism, and post-thrombotic syndrome. Catheter-related thromboses are usually diagnosed by Doppler ultrasonography or venography and treated with anticoagulation therapy for 6 weeks to a year, dependent on the extent of the thrombus, response to initial therapy, and whether thrombophilic factors persist. Prevention of catheter-related thromboses includes proper positioning of the CVC and prevention of infections; anticoagulation prophylaxis is not currently recommended.

Malfunctioning central venous catheters in children: a diagnostic approach

Central venous access is increasingly becoming the domain of the radiologist, both in terms of the insertion of central venous catheters (CVCs) and in the subsequent management of these lines. This article seeks to provide an overview of the CVC types available for paediatric patients and a more detailed explanation of the spectrum of complications that may lead to catheter malfunction. A standard catheter contrast study or 'linogram' technique is described. The normal appearances of such a study and a detailed pictorial review of abnormal catheter studies are provided, together with a brief overview of how information from catheter investigations can guide the management of catheter complications.

Treatment of catheter occlusion in pediatric patients

A proper initial assessment of catheter occlusion is the key to successful management. The assessment screens are for both thrombotic and nonthrombotic causes (including mechanical occlusion). If mechanical occlusion is excluded, thrombotic occlusion is treated with alteplase. Nonthrombotic occlusions are treated according to their primary etiologies: lipid occlusion is treated with 70% ethanol, mineral precipitates are treated with 0.1-N hydrochloric acid (HCl), drug precipitates are treated according to their pH-acidic drugs can be cleared with 0.1-N HCl, basic medications can be cleared with sodium bicarbonate or 0.1-N sodium hydroxide (NaOH). Prevention of occlusion of central venous access devices is also critical. To date, no data conclusively show heparin flushes to be superior to saline flushes. No prophylactic regimen, including low-dose warfarin, low-molecular-weight heparin, or 1 unit heparin/mL of parenteral nutrition has been endorsed by any major medical, nursing, or pharmacy group due to lack of scientific evidence. The most encouraging information on decreasing occlusion rate comes from experience with positive-pressure devices that attach to the hub of most catheter lumens and prevent retrograde blood flow and, consequently, decrease the risk of thrombus formation in the catheter lumen.