Central line thrombosis in patients with cancer

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.

Low-Molecular-Weight Heparin and Calcium Heparin in Thrombosis Prophylaxis in Patients with Percutaneous Arterial and Venous Ports for Colorectal Liver Metastases

Study Objective

The evaluation of low-molecular-weight heparin use to prevent arterial and venous thrombosis in patients with indwelling arterial Port-a-Cath implants.

Methods

From 1996 to March 2003 we placed 370 indwelling hepatic arterial catheters with a minimally invasive approach. The left distal subclavian artery was approached from beneath the left clavicle, then an angiographic study of the tumoral vascular district was performed and the gastroduodenal artery was occluded by an embolus. A polyurethane catheter was introduced distally into the hepatic artery and connected to a reservoir through a 3-4 cm long subcutaneous tunnel. In 90 patients a venous Port-a-Cath was placed for concurrent systemic chemotherapy. All 370 patients received regional chemotherapy and were treated with calcium heparin at a dose of 5000 IU twice a day and with low-molecular-weight heparin at prophylactic doses (dalteparin 2500 IU or nadroparin 3000 IU) during catheter permanence to prevent hepatic artery thrombosis. Intra-arterial trans-port radionuclide scans using technetium-99m-labeled micro-aggregated albumin were performed monthly to check the infusion distribution and hepatic artery patency. In the presence of anomalous patterns, thrombosis, pulmonary embolism or other complications, angiography and/or other diagnostic studies were performed to determine the cause of the vascular event and the local or systemic symptoms. The mean arterial and venous Port-a-Cath permanence times were 6 and 8 months, respectively.

Results

We observed episodes of hepatic artery thrombosis in 4.3% of patients. Three of these 17 patients were successfully treated by intra-arterial thrombolysis using urokinase. No venous thrombosis occurred as a consequence of regional and/or systemic chemotherapy, no episodes of arterial thrombosis were registered during arterial catheter permanence, nor did any hemorrhagic complications related to anti-coagulant therapy occur. Five patients treated with low-molecular-weight heparin required treatment suspension due to a platelet count of <40,000/dL.

Conclusion

Our experience suggests that low-molecular-weight heparin and/or calcium heparin at prophylactic doses could be useful in the prevention of arterial and venous thrombosis in patients with indwelling arterial catheters or venous Port-a-Cath treated with regional or systemic chemotherapy for hepatic metastases from colorectal cancer. The homogeneity of the patient group and the use of analogous chemotherapeutic drugs (fluoropyrimidines) avoided statistical contamination related to differences between kinds of cancer and between the chemotherapeutic agents used.

The development of central venous thrombosis in hemodialyzed patients is associated with catheter tip depth and localization

INTRODUCTION

The aim of our work was to analyze the incidence of tunneled hemodialysis catheters-related thrombosis in hemodialyzed patients depending on catheter tip depth and position and to evaluate the impact of other established risk factors responsible for development of central venous thrombosis.

METHODS

The presence of central vein thrombosis, location, and the depth of the catheter tip was reviewed by two experienced radiologists. All patients with suspected central venous thrombosis had factor V Leiden, lupus anticoagulant, and cardiolipin antibodies checked (acIgM and acIgG) and were evaluated with cat-scan venography.

FINDINGS

A total of 68 tunneled hemodialysis catheters were analyzed with CT venography for central venous thrombosis. There were no signs of central venous thrombosis when catheter tips were placed in the right atrium. There was significantly higher number of catheter tips located on the vein wall than located centrally in patients with central venous thrombosis. Higher percentage of central venous thrombosis, smaller number of tips placed in the right atrium, higher values of IgM cardiolipin antibodies, and higher number of patients with positive factor V Leiden mutation were found in group of patients with catheter tips located on vein wall.

DISCUSSION

Higher incidence of central venous thrombosis in patients with the catheter tip placed on the vein wall is a consequence of a catheter tip depth proximal of the right atrium. Increased factor V Leiden mutation and acIgM values in these patients should be observed as a result of the vein stasis caused by inappropriate catheter tip depth and localization.

D-dimer from central and peripheral blood samples in asymptomatic central venous catheter-related thrombosis in patients with cancer

Objectives

To evaluate the usefulness of a negative D-dimer in peripheral or central venous blood to screen for asymptomatic catheter-related thrombosis in cancer patients.

Methods

D-dimer was measured in blood from central venous catheter and peripheral venous samples in 48 patients with cancer. Asymptomatic catheter-related thrombosis was identified via Doppler ultrasound. Bland and Altman’s limits of agreement analysis was used to compare sample sites. Sensitivity and specificity of D-dimer was calculated.

Results

Overall, 33 of the central samples and 32 of the peripheral samples had D-dimer levels below the cutoff (≥0.3 mg/l). Mean central D-dimer was 0.31 ± 0.35 mg/l; peripheral 0.24 ± 0.22 mg/l (p = 0.5). Bland–Altman plot showed that the two sample sites were not equivalent. Catheter-related thrombosis was demonstrated in five patients, and there were three false negatives. Peripheral D-dimer had a negative predictive value of 90.9%.

Conclusions

A negative D-dimer may be useful for screening asymptomatic catheter-related thrombosis in patients with cancer, but the central and peripheral sample sites are not equivalent.

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.

Multimodality imaging of the peripheral venous system

The purpose of this article is to review the spectrum of image-based diagnostic tools used in the investigation of suspected deep vein thrombosis (DVT). Summary of the experience gained by the author as well as relevant publications, regarding vein imaging modalities taken from a computerized database, was reviewed. The imaging modalities reviewed include phlebography, color Doppler duplex ultrasonography (CDDUS), computerized tomography angiography (CTA) and venography (CTV), magnetic resonance venography (MRV), and radionuclide venography (RNV). CDDUS is recommended as the modality of choice for the diagnosis of DVT. A strategy combining clinical score and D-dimer test refines the selection of patients. Phlebography is reserved for discrepant noninvasive studies.

Generation in vivo of peptide-specific cytotoxic T cells and presence of regulatory T cells during vaccination with hTERT (class I and II) peptide-pulsed DCs

Background

Optimal techniques for DC generation for immunotherapy in cancer are yet to be established. Study aims were to evaluate: (i) DC activation/maturation milieu (TNF-α +/- IFN-α) and its effects on CD8+ hTERT-specific T cell responses to class I epitopes (p540 or p865), (ii) CD8+ hTERT-specific T cell responses elicited by vaccination with class I alone or both class I and II epitope (p766 and p672)-pulsed DCs, prepared without IFN-α, (iii) association between circulating T regulatory cells (Tregs) and clinical responses.

Methods

Autologous DCs were generated from 10 patients (HLA-0201) with advanced cancer by culturing CD14+ blood monocytes in the presence of GM-CSF and IL-4 supplemented with TNF-α [DCT] or TNF-α and IFN-α [DCTI]. The capacity of the DCs to induce functional CD8+ T cell responses to hTERT HLA-0201 restricted nonapeptides was assessed by MHC tetramer binding and peptide-specific cytotoxicity. Each DC preparation (DCT or DCTI) was pulsed with only one type of hTERT peptide (p540 or p865) and both preparations were injected into separate lymph node draining regions every 2–3 weeks. This vaccination design enabled comparison of efficacy between DCT and DCTI in generating hTERT peptide specific CD8+ T cells and comparison of class I hTERT peptide (p540 or p865)-loaded DCT with or without class II cognate help (p766 and p672) in 6 patients. T regulatory cells were evaluated in 8 patients.

Results

(i) DCTIs and DCTs, pulsed with hTERT peptides, were comparable (p = 0.45, t-test) in inducing peptide-specific CD8+ T cell responses. (ii) Class II cognate help, significantly enhanced (p < 0.05, t-test) peptide-specific CD8+T cell responses, compared with class I pulsed DCs alone. (iii) Clinical responders had significantly lower (p < 0.05, Mann-Whitney U test) T regs, compared with non-responders. 4/16 patients experienced partial but transient clinical responses during vaccination. Vaccination was well tolerated with minimal toxicity.

Conclusion

Addition of IFN-α to ex vivo monocyte-derived DCs, did not significantly enhance peptide-specific T cell responses in vivo, compared with TNF-α alone. Class II cognate help significantly augments peptide-specific T cell responses. Clinically favourable responses were seen in patients with low levels of circulating T regs.

Risk of venous thromboembolism in patients undergoing cancer surgery and options for thromboprophylaxis

Patients with cancer have an increased risk of developing venous thromboembolism (VTE) due to a hypercoagulable state associated with malignancy. This risk is further complicated in patients undergoing cancer-related surgery due to immobility, other cancer treatments, and biologic changes associated with surgery. Despite this relatively high risk of VTE, many patients are not prescribed adequate prophylaxis in the pre- or post-operative periods. This article reviews available measures for thromboprophylaxis in light of current guidelines.

Venous Thromboembolism in Patients With Cancer Part I: Survey of Oncology Nurses' Attitudes and Treatment Practices for Ambulatory Settings

Patients with cancer have a higher incidence of venous thromboembolism (VTE). Little information currently exists on VTE and the understanding and beliefs of oncology nurses. Therefore, the attitudes and treatment practices of ambulatory oncology nurses were surveyed to determine the current knowledge base of VTE in patients with cancer. Survey results are presented along with a thorough literature review of thromboembolism and the unique risk factors for this frequent complication in patients with cancer. The causes of VTE in this patient population often are multifactorial and include hypercoagulability, stasis, and vascular endothelial damage from procedures or the neoplastic process itself. In particular, chemotherapy administration can increase the risk of thrombosis considerably. New therapies, including thalidomide, require oncology nurses caring for these patients to have heightened awareness of the potential for thrombogenic complications. This is the first of two articles that address the problem of thromboembolism in patients with cancer, including the survey results. (See part II on page 465.) Oncology nurses are essential in the care of VTE in patients with cancer and can help with patient identification, treatment, and compliance for improved patient outcomes.

Prevalence of upper extremity deep venous thrombosis diagnosed by color Doppler duplex sonography in cancer patients with central venous catheters

OBJECTIVE

The purpose of this study was to review the literature concerning upper extremity deep venous thrombosis (UEDVT) diagnosed by color Doppler duplex sonography (CDDS) in cancer patients with indwelling central venous catheters (CVCs).

METHODS

From computerized databases (MEDLINE and Ovid), relevant publications regarding CDDS of the upper limb veins in cancer patients with CVCs were reviewed.

RESULTS

Patients with malignancy have a higher rate of thrombosis, which is increased by the presence of CVCs. Screening CDDS in asymptomatic patients showed CVC-related UEDVT in 11.7% to 44% of patients. In symptomatic cancer patients, the range was similar to the asymptomatic ones, 6.7% to 48%. The presence of a CVC almost doubled the incidence of UEDVT in symptomatic patients. Color Doppler duplex sonography is an accurate examination for the diagnosis of UEDVT, with sensitivity ranging from 78% to 100% and specificity ranging from 82% to 100%. The main obstacle for the diagnosis of UEDVT is the presence of overlying bones, making it difficult to visualize and impossible to directly assess by compression techniques. Color and spectral Doppler sonography and the use of small transducers aid in the diagnosis. When several parameters are evaluated in combination, CDDS is a reliable method for diagnosing CVC-related thrombosis.

CONCLUSIONS

Great variability in the prevalence of catheter-related thrombosis in cancer patients has been reported, although it is uniformly higher compared with patients without cancer. Color Doppler duplex sonography is the modality of choice for the diagnosis of CVC-related UEDVT in symptomatic cancer patients and for screening for asymptomatic thrombosis in this specific population.

The heparins and cancer: review of clinical trials and biological properties

The association between cancer and thromboembolic disease is a well-known phenomenon and can contribute significantly to the morbidity and mortality of cancer patients. The spectrum of thromboembolic manifestations in cancer patients includes deep vein thrombosis, pulmonary embolism, but also intravascular disseminated coagulation and abnormalities in the clotting system in the absence of clinical manifestations. Unfractionated heparin (UFH) and particularly low molecular weight heparins (LMWH-s) are widely used for the prevention and treatment of thromboembolic manifestations that commonly accompany malignancies. Malignant growth has also been linked to the activity of heparin-like glycosaminoglycans, to neoangiogenesis, to protease activity, to immune function and gene expression. All these factors contribute in the proliferation and dissemination of malignancies. Heparins may play a role in tumour cell growth and in cancer dissemination. The aims of the study are to review the efficiency of heparins in the prevention and treatment of cancer-related thromboembolic complications, and review the biological effects of heparins. Heparins are effective in reducing the frequency of thromboembolic complications in cancer patients. Meta-analyses comparing unfractionated heparins and LMWH-s for the treatment of deep vein thrombosis have shown better outcome with a reduction of major bleeding complications in patients treated with LMWH-s. LMWH have antitumour effects in animal models of malignancy: heparin oligosaccharides containing less than 10 saccharide residues have been found to inhibit the biological activity of basic fibroblast growth factor (bFGF), whereas heparin fragments with less than 18 saccharide residues have been reported to inhibit the binding of vascular endothelial growth factor (VEGF) to its receptors on endothelial cells. It has been shown that LMWH, in contrast with UFH, can hinder the binding of growth factors to their high-affinity receptors as a result of its smaller size. In vitro heparin fragments of less than 18 saccharide residues reduce the activity of VEGF, and fragments of less than 10 saccharide residues inhibit the activity of bFGF. Small molecular heparin fractions have also been shown to inhibit VEGF- and bFGF-mediated angiogenesis in vivo, in contrast with UFH. Moreover, heparin may influence malignant cell growth through other different interrelated mechanisms: inhibition of (1) heparin-binding growth factors that drive malignant cell growth; (2) tumour cell heparinases that mediate tumour cell invasion and metastasis; (3) cell surface selectin-mediated tumour cell metastasis and blood coagulation. The above evidence, together with favourable pharmaco-properties and with a reduction in major bleeding complications, suggests an important role for LMWH-s in thromboprophylaxis and in the therapy of venous thromboembolism in cancer patients. There is sufficient experimental data to suggest that heparins may interfere with various aspects of cancer proliferation, angiogenesis, and metastasis formation. Large-scale clinical trials are required to determine the clinical impact of the above activities on the natural history of the disease.

Application of upper extremity radionuclide venography as a diagnostic approach for Port-A catheter thrombosis

BACKGROUND

To investigate the role of upper extremity radionuclide venography as a potential diagnostic modality in the assessment of venous thrombosis associated with a Port-A catheter.

METHODS

Fourteen symptomatic patients who had received Port-A catheter implantation were enrolled. A dynamic nuclear medicine flow study was performed with intravenous administration of Technetium-99m macroaggregated albumin to both upper extremities. Imaging patterns of the venous system were categorized as patency, partial obstruction, and total occlusion.

RESULTS

The findings of the dynamic images clearly demonstrated clinical problems. Three patients were free of a definite venous flow change. Three patients had partial obstruction of venous return. A significant cut-off of venous return was demonstrated in 8 patients, and total occlusions were hence diagnosed. All patients underwent this procedure smoothly without any complication.

CONCLUSION

These results suggest that upper extremity radionuclide venography is an easily performed and effective method for diagnosing Port-A catheter thrombosis in clinical practice.