Therapy Insight: venous-catheter-related thrombosis in cancer patients

Focal Adhesion Kinase Inhibitor Inhibits the Oxidative Damage Induced by Central Venous Catheter via Abolishing Focal Adhesion Kinase-Protein Kinase B Pathway Activation

The vascular injury induced by central venous catheter (CVC) indwelling is the basis for the occurrence and development of CVC-related complications, such as phlebitis, venous thrombosis, and catheter-related infections. Focal adhesion kinase (FAK) and FAK-protein kinase B (AKT) signaling pathway are of great significance in tissue repair after trauma. Here, we investigated the role and mechanism of the FAK inhibitor (1,2,4,5-phenyltetramine tetrahydrochloride (Y15)) in oxidative damage caused by CVC. EA.hy926 cells were divided into the control group (normal control), CVCs+scratches group (the intercepted CVC segments coculturing with scratched EA.hy926 cells), and CVCs+scratches+Y15 group (Y15 was added to the cell culture supernatant with CVCs + scratches at a final concentration of 50 μmol·L⁻¹). New Zealand rabbits were randomly divided into the control group (normal control), CVC group (CVC was inserted through the rabbit's right jugular vein to the junction of the right atrium and superior vena cava), and CVC+Y15 group (CVC was immersed in a 50 μmol·L⁻¹ Y15 solutions before insertion). The levels of markers and proteins related to oxidative damage in cells, cell culture supernatant, serum, and external jugular vein were measured by commercial kits and western blot, respectively. We found that Y15 treatment significantly decreased ROS and MDA levels and increased cell viability, NO, and SOD levels in a time-dependent manner in rabbit serum and cell culture supernatant. In addition, Y15 effectively reduced the CVC-induced pathological changes of damaged vascular tissues. Y15 also downregulated the levels of p-FAK Tyr 397 and p-Akt Ser 473 in damaged external jugular vein and EA.hy926 cells. These findings suggest that Y15 alleviated CVC-induced oxidative damage to blood vessels by suppressing focal FAK-Akt pathway activation.

Treatment of cancer-associated thrombosis: The evolution of anticoagulant choice and clinical insights into practical management

Low-molecular-weight heparin (LMWH) therapy is recommended over vitamin K antagonists (VKAs) for the treatment of cancer-associated thrombosis (CAT) and extended therapy is recommended in those with active cancer to prevent recurrent thrombosis. However, the inconvenience of daily subcutaneous injections and the cost of LMWH therapy hinder long-term use. Observational data demonstrate that persistence with LMWH therapy is low in clinical practice and that many patients are switched to oral alternatives - namely VKAs and direct oral anticoagulants (DOACs). Recently, the efficacy and safety of apixaban, edoxaban, and rivaroxaban versus LMWH therapy for the treatment of CAT have been demonstrated in randomized trials. This review provides a critical evaluation of studies with DOACs in this setting and an update on the guidance regarding anticoagulant use for the treatment of CAT. In recognition of the heterogeneity of patients with cancer and the challenges of CAT, patient cases with expert clinical perspectives are presented.

Central Venous Catheter-Associated Thrombosis in the Perioperative Period: A Frequent Complication in Cancer Patients that can be Detected Early with Doppler Examination

Aims and background

The aim of the study was to determine the incidence of venous thrombosis in cancer patients with central venous catheters inserted perioperatively.

Methods and study design

A prospective analysis was performed with 68 patients in whom central venous catheters were placed perioperatively. Cancer patients with planned central venous catheters had prophylaxis with low-molecular-weight heparin. Patient characteristics, procedure-related complications and venous thrombosis related to central venous catheters were recorded. In order to detect the venous thrombosis, color Doppler sonography was used after removal of the central venous catheter.

Results

The median age of the 68 patients was 55 years (range, 24–83). The median duration of catheter placement in patients was 9 days (range, 1–24). Venous thrombosis was detected in 45 (66.2%) patients: at the superficial veins (jugular and subclavian veins) in 27 patients, stretching from superficial veins into the vena cava in 8 cases, in the vena cava in 2 cases, in the right atrium in 2 cases, and at more then one place in 6 patients. Total thrombosis was detected only in 3 patients.

Conclusions

Cancer patients have a high central venous catheter-related thrombosis risk perioperatively despite prophylactic anticoagulation. Color Doppler sonography is a rapid and noninvasive technique and it is accurate in the diagnosis of venous thrombosis. Early detection of venous thrombosis is important to prevent the systemic and fatal complication of the thrombosis. Free full text available at www.tumorionline.it

Surface Modification of Polymeric Biomaterials Using Recombinant Spider Silk Proteins

The performance of biomaterials largely depends on the materials biocompatibility, which is directly related to unwanted side effects like foreign body responses and inflammation, and the potential of interaction of cells with its surface, for example, cell adhesion. In the distinct application of catheters, low or even no cell adhesion is eligible. To influence the properties of existing and commonly used biomaterials and to further increase their biocompatibility, a coating with a recombinantly produced spider silk protein as outer layer was applied on three selected catheter polymers (polyurethane, polytetrafluoroethylene, silicone) and evaluated based on cell adhesion. The tested cell types, HaCaT keratinocytes (epidermal cells), B50 neuronal cells, C2C12 myoblasts (muscle cells) and BALB/3T3 fibroblasts (connective tissue), exhibited low or no adhesion on the silk-coated materials. In combination with the lack of toxicity, the good biocompatibility, and the low body response, it could be shown that silk coatings have a high potential as a biomedical coating material, e.g., for catheters.

Venous access catheter-related thrombosis in patients with cancer

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

Extra-abdominal venous thromboses at unusual sites

Venous thrombosis typically involves the lower extremities. Rarely, it can occur in cerebral, splanchnic, or renal veins, with a frightening clinical impact. Other rare manifestations are upper-extremity deep vein thrombosis, that can complicate with pulmonary embolism and post-thrombotic syndrome, and retinal vein occlusion, significantly affecting the quality of life. This review is focused on venous thromboses at unusual extra-abdominal sites. Local infections or cancer are frequent in cerebral sinus-venous thrombosis. Upper-extremity deep vein thrombosis is mostly due to catheters or effort-related factors. Common risk factors are inherited thrombophilia and oral contraceptive use. Acute treatment is based on heparin; in cerebral sinus-venous thrombosis, local or systemic fibrinolysis should be considered in case of clinical deterioration. Vitamin-K antagonists are recommended for 3-6 months; indefinite anticoagulation is suggested for recurrent thrombosis or unprovoked thrombosis and permanent risk factors. However, such recommendations mainly derive from observational studies; there are no data about long-term treatment of retinal vein occlusion.

S-1 for the treatment of gastrointestinal cancer

INTRODUCTION

5-Fluorouracil (5-FU)-based regimens are used worldwide as the standard treatment in chemotherapy for gastric cancer. S-1 , a fourth-generation oral fluoropyrimidine that combines tegafur and two biochemical modulators: gimeracil and oteracil potassium, is now attracting considerable interest.

AREAS COVERED

This review addresses the clinical evidence of S-1 in gastrointestinal malignancies, such as gastric, colorectal, pancreatic and biliary tract cancers. S-1 has demonstrated advantages over standard therapies, in both advanced and postoperative settings, in large Phase III studies. S-1 alone or S-1 plus cisplatin is recommended in the 2010 Gastric Cancer Treatment Guidelines, by the Japanese Gastric Cancer Association. Results from Phase III studies have demonstrated that S-1 in combination with chemotherapies, such as cisplatin in gastric cancer, and irinotecan and oxaliplatin in colorectal cancers, is non-inferior to conventional 5-FU-based standard regimens, with the benefit of convenience and reduced toxicity.

EXPERT OPINION

The excellent design of S-1 aimed to reduce toxicity by avoiding certain routes of degradation, and to enhance activity by reducing catabolism. This has provided not only a suitable alternative to 5-FU, but also higher efficacy.

S-1 as a core anticancer fluoropyrimidine agent

INTRODUCTION

5-FU is a core anticancer agent for GI and other malignancies, and infusional 5-FU regimens have been widely utilized. Orally administrable fluoropyrimidine prodrugs have been developed to enhance the anticancer efficacy of 5-FU and to reduce its adverse reactions.

AREAS COVERED

S-1 is an FT-based oral 5-FU prodrug in combination with a DPD inhibitor (CDHP) and an OPRT inhibitor (Oxo), which exerts the following effects: i) maintaining normal gut immunity, Oxo can decrease GI toxicities of 5-FU; ii) sustaining high plasma 5-FU concentrations, Cmax of FBAL after S-1 administration is extremely low, which dramatically decreases adverse reactions such as HFS, neurotoxicities and cardiotoxicities; iii) plasma 5-FU concentrations vary less extensively after S-1 administration and iv) S-1 can be safely administered to patients with DPD deficiency. Furthermore, the alternate-day S-1 administration can reduce the GI toxicities and myelotoxicities of 5-FU without reducing its anticancer efficacy, enabling patients to continue the oral administration for 6 - 12 months.

EXPERT OPINION

Replacement of regimens with infusional 5-FU and other fluoropyrimidines by the alternate-day S-1 administration may be recommended because the latter procedure is efficient for patients while sustaining the enhanced anticancer efficacy of 5-FU and without reducing its dose intensity.

5-fu metabolism in cancer and orally-administrable 5-fu drugs

5-Fluorouracil (5-FU) is a key anticancer drug that for its broad antitumor activity, as well as for its synergism with other anticancer drugs, has been used to treat various types of malignancies. In chemotherapeutic regimens, 5-FU has been combined with oxaliplatin, irinotecan and other drugs as a continuous intravenous infusion. Recent clinical chemotherapy studies have shown that several of the regimens with oral 5-FU drugs are not inferior compared to those involving continuous 5-FU infusion chemotherapy, and it is probable that in some regimens continuous 5-FU infusion can be replaced by oral 5-FU drugs. Historically, both the pharmaceutical industry and academia in Japan have been involved in the development of oral 5-FU drugs, and this review will focus on the current knowledge of 5-FU anabolism and catabolism, and the available information about the various orally-administrable 5-FU drugs, including UFT, S-1 and capecitabine. Clinical studies comparing the efficacy and adverse events of S-1 and capecitabine have been reported, and the accumulated results should be utilized to optimize the treatment of cancer patients. On the other hand, it is essential to elucidate the pharmacokinetic mechanism of each of the newly-developed drugs, to correctly select the drugs for each patient in the clinical setting, and to further develop optimized drug derivatives.

Disconnection of chamber and catheter as a complication of central venous catheter type port-a-cath

The use of a central vein catheter (CVC) type port-a-cath (VPS), apart from the comfort it provides to the patient undergoing chemotherapy, also carries certain complications. In this study, our patient was subjected to chemotherapy after a radical breast cancer operation and was given a CVC type VPS. After further care, a rare complication was verified--disconnection of the chamber and catheter, which one was visually identified in the right heart chamber. As the patient was vitally endangered, she was immediately hospitalized and the catheter was removed by catheterization of the right femoral vein, with scopic imaging. Early diagnosis and localization of the problem prevented more severe complications and mortality.

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

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

Prevention and management of central venous catheter occlusion and thrombosis in children with cancer

BACKGROUND

The views and clinical practice of children's cancer units were surveyed regarding management of central venous catheter (CVC) occlusion (CVC-occlusion), CVC-related thrombosis (CVC-thrombosis) and thromboembolism (CVC-thromboembolism).

PROCEDURE

A questionnaire was sent to all 22 United Kingdom Children's Cancer Study Group centres, requesting information about their views of the importance of, and their practices regarding, prophylaxis, diagnosis and treatment of CVC-occlusion/thrombosis.

RESULTS

Twenty (91%) centres responded. Eighty percent, 80% and 70%, respectively, stated that CVC-occlusion, CVC-thrombosis and CVC-thromboembolism were clinically important concerns. All centres used heparinised saline flushes as prophylaxis against CVC-occlusion, with little variation (</=30% centres) in frequency, volume and heparin concentration. Symptoms or signs suggesting partial CVC-occlusion, total CVC-occlusion, or CVC-thrombosis/thromboembolism were always investigated in 20%, 55% and 85% of centres, respectively, but with considerable variability in the nature and sequence of investigations performed, which included (depending on the clinical scenario) chest X-ray, contrast linography or venography, ultrasonography, echocardiography and magnetic resonance venography. A fibrinolytic lock was administered before investigation of CVC-occlusion in 75% of centres. Although 45%, 60% and 80%, respectively, always treated partial CVC-occlusion, total CVC-occlusion or CVC-thrombosis/thromboembolism, the type and order of treatments differed greatly between centres, especially for CVC-thrombosis/thromboembolism, in which CVC removal, systemic anticoagulation (heparin or warfarin), local or systemic fibrinolysis, or thrombectomy were performed in at least some centres.

CONCLUSIONS

The clinical practice of UKCCSG centres regarding prevention, investigation and treatment of CVC-occlusion/thrombosis varies greatly. Additional trials should facilitate development of evidence-based guidelines.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Management of venous port systems in oncology: a review of current evidence

BACKGROUND

Over the last decades, many changes have occurred in oncology with new chemotherapy combinations and more complex application schemes becoming available. Central venous catheters and implantable venous port systems have become widely used and have facilitated the problem of vascular access. However, important complications are associated with permanent central venous catheters.

MATERIAL AND METHODS

This review summarizes evidence on venous port system use published in Medline up to February 2007. Moreover, recent guidelines for the prevention and management of catheter-related infections issued by the Infectious Diseases Society of America, the American College of Critical Care Medicine, the Society for Healthcare Epidemiology of America, the Center for Disease Control and Prevention, Atlanta, and the Infectious Diseases Working Party of the German Society of Hematology and Oncology are included.

RESULTS

Sterile precautions are essential when implanting and accessing port systems. Infections must be treated with adequate antimicrobial therapy. Catheter-related thromboembolic complications were found at a rate of 12-64% in retrospective studies. Five current clinical trials investigated the effect of prophylactic anticoagulation with either low molecular weight heparin or warfarin in cancer patients with central venous devices. On the basis of these results, routine anticoagulation cannot be recommended.

CONCLUSIONS

This article reviews the current literature on long-term complications of venous port systems, focusing on infection and thrombosis. In addition, it summarizes the evidence regarding routine maintenance of port systems in follow-up care.

Risk Factors for Venous Thromboembolism After Lung Transplantation

BACKGROUND

The risk factors for venous thromboembolism (VTE) following lung transplantation are not well established. We aimed to estimate the incidence of VTE and to identify the risk factors for VTE after lung transplantation.

METHODS

We performed a nested case-control study within the cohort of 121 patients who underwent lung transplantation at our center between August 2001 and July 2005. Control subjects were matched to case patients on the number of days from the time of transplant. Cox proportional hazards models were used to identify risk factors for VTE.

RESULTS

Twenty-four patients had deep vein thromboses, and 6 patients had pulmonary emboli (3 patients had both) [22% of the cohort]. In multivariate models, older age (p < 0.05), diabetes mellitus (p = 0.03), and pneumonia (p = 0.02) were associated with a higher rate of VTE.

CONCLUSIONS

VTE is a frequent complication of lung transplantation. Older age, diabetes, and pneumonia increase the rate of VTE. Future studies of intensive VTE prophylaxis may be warranted.

Pathogenesis, clinical and laboratory aspects of thrombosis in cancer

The relationship between increased clotting and malignancy is well recognized, though the bidirectional development of this association is often overlooked. In the challenging cancer biology, transforming genes often act in concert with numerous epigenetic factors, including hypoxia, inflammation, contact between blood and cancer cells, and emission of procoagulant vesicles from tumors, to determine a net imbalance of the hemostatic potential which is detectable by a variety of laboratory tests. Procoagulant factors, in particular, are intimately involved in all aspects of hemostatic, cell proliferation and cellular signalling systems. However, the biggest as yet unresolved question is why cancer patients develop thrombosis? Since the thrombus itself does not apparently contributes directly to the tumor biology, enhanced hemostasis activation in cancer patients may be interpreted according to the most recent biological evidences. Coagulation and cancer biology interact bidirectionally in a "vicious cycle", in which greater tumor burden supplies greater procoagulants (tissue factor, cancer procoagulant) and thrombin, which would in turn act as strong promoters of cancer growth and spread. In this perspective, thrombosis may be interpreted as a epiphenomenon of an intricate an effective biological feedback to maintain or promote cancer progression. In this review article, we briefly analyze the pathogenesis, laboratory, clinical and therapeutic features of cancer and thrombosis.