Late vascular occlusion of central lines in pediatric malignancies

Central-line-associated bloodstream infections and central-line-associated non-CLABSI complications among pediatric oncology patients

OBJECTIVE

To assess central venous catheter (CVC) harm in pediatric oncology patients, we explored risks for central-line-associated bloodstream infections (CLABSIs) and central-line-associated non-CLABSI complications (CLANCs).

DESIGN

Retrospective cohort study.

SETTING

Midwestern US pediatric oncology program.

PATIENTS

The study cohort comprised 592 pediatric oncology patients seen between 2006 and 2016.

METHODS

CLABSIs were defined according to Centers for Disease Control and Prevention (CDC)/National Health Safety Network (NHSN) definitions. CLANCs were classified using a novel definition requiring CVC removal. Patient-level and central-line-level risks were calculated using a negative binomial model to adjust for correlations between total events and line numbers.

RESULTS

CVCs were inserted in 62% of patients, with 175,937 total catheter days. The inpatient CLABSI and CLANC rates were 5.8 and 8.5 times higher than outpatient rates. At the patient level, shared risks included acute myeloid leukemia (AML) and age <1 year at diagnosis. At the line level, shared risks included age <1 year at diagnosis, non-mediports, and >1 lumen. AML was a CLABSI-specific risk. CLANC-specific risks included non-brain-tumor diagnosis, younger age at diagnosis or central-line placement, and age <1 year at diagnosis or line placement. Multivariable risks were for CLABSI >1 lumen and for CLANC age <1 year at placement.

CONCLUSIONS

Among patients with CVCs, CLABSI and CLANC rates were similar, higher among inpatients than outpatients. For both CLABSIs and CLANCs, infants and patients with AML were at higher risk. In both univariate and multivariate models, lines with >1 lumen were associated with CLABSIs and placement during infancy with CLANCs.

A retrospective analysis of risk factors associated with catheter-related thrombosis: a single-center study

BACKGROUND

Catheter-related thrombosis may lead to catheter infections and failure, further deep venous thrombosis, and pulmonary embolism. Recognizing the risk factors for catheter-related thrombosis is extremely important to inform the development of catheter care guidelines.

METHODS

Data were collected from a total of 1,532 patients who had undergone venous catheterization, including indwelling catheterization from 19 March 2019 to 30 March 2019 in the Sun Yat-sen Memorial Hospital. The factors for which data were to be collected included the patients' physical characteristics, catheter-related factors, and catheter care-related factors. Logistic regression analysis, the chi-squared test, Fisher's exact test, and the t-test were used to analyze the data.

RESULTS

Of the 1,532 patients studied, 28 developed intraductal thrombi, and of the factors analyzed, malignancy, a catheterization history, a history of thrombophilia, surgery during the week before catheterization, the catheterization duration, and anticoagulant therapy were significant risk factors associated with catheter-related thrombosis (all p < 0.05). There were no significant associations between the catheter brand, the number of lumens, the insertion direction, or the factors associated with catheter care and catheter-related thrombosis (all p > 0.05).

CONCLUSION

Our study incorporated clear and systematic risk factors associated with catheter-related thrombosis. Malignancy, history of thrombophilia, history of catheterization, surgery during the week before catheterization, and catheterization duration were associated with increased risks of catheter-related thrombosis. Prophylactic anticoagulation was effective for preventing and treating catheter-related thrombosis.

Calcification and abscess formation around the catheter tip of a central venous access port: a case report

Background

Thrombosis of the internal jugular vein occasionally occurs in association with long-term placement of a central venous catheter; however, such complications rarely involve calcification within the blood vessels. We report a case of calcification and abscess formation around a central venous catheter tip.

Case presentation

Our patient was an 84-year-old Asian woman who developed a fever that had started approximately 5 months after the placement of a central venous catheter. At the time of presentation, blood tests showed a marked inflammatory response, and chest computed tomography showed a high absorption area and air density around the catheter tip. Therefore, the patient was diagnosed with abnormal intravascular calcification and a deep neck abscess associated with long-term central venous catheter placement. The initial plan was to administer antibiotics and remove the central venous catheter. However, central venous catheter removal was deemed difficult due to the calcification and therefore required an incision. Because of the patient’s advanced age and dementia, her family requested antibiotic treatment only. Following antibiotic treatment, the patient’s inflammatory response normalized, and her fever resolved. The treatment was discontinued, and the patient’s condition gradually stabilized.

Conclusions

Catheter-related complications of central venous catheter placement include vascular occlusion, extravasation of the infusion, and infection. However, abnormal calcification in the blood vessels is extremely rare, and there has been only one case report of a neonate with central venous catheter-related vascular calcification in Japan. The etiology of intravascular calcification is considered to be related to the infusion content and the infusion rate of high caloric infusions and blood products. The incidence of complications associated with long-term central venous catheter placement is expected to increase with the increasing aging of the population and advances in chemotherapy. The report of the clinical course of this rare case adds to the body of knowledge in this area.

Interventional management of central vein occlusion in patients with peripherally inserted central catheter placement

OBJECTIVE

This study evaluated the incidence of central vein occlusion (CVO) and analyzed the interventional management for CVO during peripherally inserted central catheter (PICC) placement to suggest an adequate management protocol to ensure the success and patency of PICCs.

METHODS

We retrospectively reviewed the records of 2568 PICCs to identify CVO in two medical centers between January 2016 and June 2017. Procedural images were reviewed for the following items: date and indication for the PICC; type of catheter; accessed vein and arm; characteristics of CVO on ascending arm venography; PICC placement technique; indwelling period of the PICC; and follow-up records. A guidewire passage trial was performed to the CVO, as follows: a trial with a 0.018-inch single or double guidewire through the pretrimmed PICC lumen; and a trial with a combination of a 0.035-inch guidewire and a curved 5F diagnostic catheter through the PICC introducer sheath.

RESULTS

The incidence of CVO was 3.2% (71/2232), and 59 patients were analyzed (23 men; mean age, 69 ± 11 years; median age, 80 years; age range, 31-92 years). Forty-four patients had thrombotic CVO, and 12 patients had acute thrombotic CVO. Thirty-six patients had occlusion of the left innominate vein, and six patients had contiguous involvement of the adjacent central vein. Forty-two patients had obtuse stump morphology of CVO, and 28 patients had grade >III collateral development. The PICC indwelling time was statistically different between the group with successful catheter advancement (n = 36, success group) and the group with failed catheter advancement (n = 18, failure group; P = .007) with ipsilateral trimmed PICCs. Eight patients had a symptomatic catheter associated with upper extremity deep venous thrombosis (UEDVT; <30 days), one in the success group and seven in the failure group. The incidence of catheter-associated UEDVT after primary PICC placement on each arm was statistically different between the success and failure groups (P = .004).

CONCLUSIONS

A PICC passage trial for ipsilateral CVO is challenging but frequently successful with a simple guidewire technique, which can preserve catheter patency, decrease contralateral arm access, and prevent the development of new catheter-associated UEDVT.

Prevalence of Symptomatic and Asymptomatic Thrombosis in Pediatric Oncology Patients With Tunneled Central Venous Catheters

BACKGROUND

Pediatric oncology patients with tunneled central venous catheters (CVCs) are at increased risk to develop venous thromboembolic events (VTEs), but the true prevalence of (a)symptomatic VTE is unknown. Aim of this study was to evaluate the prevalence of (a)symptomatic VTE in pediatric oncology patients with tunneled CVCs.

PROCEDURE

All patients were included in the Aristocaths study: a randomized controlled multicenter trial investigating the prophylactic effect of 70% ethanol locks on CVC-associated bloodstream infections (CABSIs) were eligible for this study. We assessed the following outcomes: (i) symptomatic VTE and (ii) asymptomatic CVC-related VTE (using ultrasound [US]). Follow-up was 6 months, unless patients developed one of the following events: VTE, CABSI, CVC removal, or death.

RESULTS

We included 305 patients (hematologic malignancy, n = 148; solid tumor, n = 157), median age 9 years (range, 1-18 years). Symptomatic VTE was detected in 8 of 305 patients (2.6%; 95% confidence interval [CI]: 1.1-5.1%), which was related to the CVC in three patients. Patients (185/305) were evaluated with US: 11 of 185 (5.9%; 95% CI: 3.0-10.4%) patients had asymptomatic CVC-related VTE.

CONCLUSIONS

Prevalence of both symptomatic VTE and asymptomatic CVC-related VTE was low compared to other studies, which may be explained by the inclusion of patients with solid tumors, reduction of CABSI by ethanol, use of tunneled CVCs, and use of US.

Port-a-cath-related thrombosis and postthrombotic syndrome in pediatric oncology patients

OBJECTIVE

To investigate Port-A-Cath (PAC)-related thrombosis and postthrombotic syndrome (PTS) in children with cancer.

STUDY DESIGN

The study population was a consecutive cohort of children diagnosed with cancer and a PAC implanted at diagnosis. Children were evaluated for the presence of PAC-related thrombosis by magnetic resonance venography and the presence of congenital prothrombotic risk factors and PTS.

RESULTS

A total of 114 children (median age, 6.04 years) were included. Of these children, 48 (42%) were treated for solid tumors and 66 (58%) were treated for hematopoietic tumors, including 38 for acute lymphoblastic leukemia. At the time of magnetic resonance venography, 42 children (37%) had the PAC still in place, and 72 (63%) had the PAC removed. Overall, PACs were in place for a total of 324.92 PAC-years. PAC-related thrombosis was detected in 45 children (39.5%) with a current or previous PAC. Of these, 21 (47%) had a solid tumor, 14 (31%) had acute lymphoblastic leukemia, and 10 (22%) had another hematopoietic tumor. Younger age at diagnosis, female sex, duration of PAC use, and left-side PAC placement were independently associated with an increased risk of thrombosis, whereas asparaginase therapy and the presence of inherited prothrombotic risk factors were not. Mild PTS (ie, presence of prominent collateral vessels in the skin) was present in 5.6% of the children.

CONCLUSION

PAC-related thrombosis is common in pediatric oncology patients. In some children, thrombotic complications can lead to the development of PTS.

Systemic treatments for the prevention of venous thrombo-embolic events in paediatric cancer patients with tunnelled central venous catheters

BACKGROUND

Venous thrombo-embolic events (VTEs) occur in 2.2% to 14% of paediatric cancer patients and cause significant morbidity and mortality. The malignant disease itself, the cancer treatment and the presence of central venous catheters (CVCs) increase the risk of VTE.

OBJECTIVES

The primary objective of this review was to investigate the effects of preventive systemic treatments in paediatric cancer patients with tunnelled CVCs on (a)symptomatic VTE. Secondary objectives of this review were to investigate adverse effects of systemic treatments for the prevention of (a)symptomatic VTE in paediatric cancer patients with tunnelled CVCs; and to investigate the effects of systemic treatments in the prevention of (a)symptomatic VTE with CVC-related infection in paediatric cancer patients with tunnelled CVCs.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 8 2012), MEDLINE (1966 to August 2012) and EMBASE (1966 to August 2012). In addition, we searched reference lists from relevant articles and conference proceedings of the International Society for Paediatric Oncology (SIOP) (from 2006 to 2011), the American Society of Clinical Oncology (ASCO) (from 2006 to 2011), the American Society of Hematology (ASH) (from 2006 to 2011) and the International Society of Thrombosis and Haematology (ISTH) (from 2006 to 2011). We scanned the International Standard Randomised Controlled Trial Number (ISRCTN) Register and the National Institute of Health (NIH) Register for ongoing trials (www.controlled-trials.com) (August 2012), and we contacted the authors of eligible studies if additional information was required.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing systemic treatments to prevent venous thrombo-embolic events (VTEs) in paediatric cancer patients with tunnelled CVCs with a control intervention or no systemic treatment. For the description of adverse events, cohort studies were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data and performed risk of bias assessment of included studies. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Three RCTs and three CCTs (including 1291 children) investigated the prevention of VTE (low molecular weight heparin (LMWH) n = 134, antithrombin (AT) supplementation n = 37, low-dose warfarin n = 31, cryoprecipitate and/or fresh frozen plasma (FFP) supplementation n = 240, AT supplementation and LMWH n = 41). AT, cryoprecipitate and FFP were supplemented only in cases of AT or fibrinogen deficiency. Of the six included RCTs/CCTs, five investigated the prevention of VTE compared with no intervention (n = 737), and one CCT compared AT supplementation and LMWH with AT supplementation (n = 71). All studies had methodological limitations, and clinical heterogeneity between studies was noted.We found no significant effects of systemic treatments compared with no intervention in preventing (a)symptomatic VTE and no differences in adverse events (such as major and/or minor bleeding; none of the studies reported thrombocytopenia, heparin-induced thrombocytopenia (HIT), heparin-induced thrombocytopenia with thrombosis (HITT), death as a result of VTE, removal of CVC due to VTE, CVC-related infection, and post-thrombotic syndrome (PTS)) between experimental and control groups. Two studies with comparable participant groups and interventions were included for meta-analyses (n = 182). In the experimental group, 1/68 (1.5%) children were diagnosed with symptomatic VTE, as were 4/114 (3.5%) in the control group (best case scenario: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.09 to 4.78). These studies also evaluated asymptomatic CVC-related VTE: In the experimental group, 22/68 (32.4%) were diagnosed with asymptomatic VTE, as were 35/114 (30.7%) in the control group (best case scenario: RR 1.02, 95% CI 0.40 to 2.55). Heterogeneity was substantial for this analysis: I(2) = 73%.The attribution of LMWH to AT supplementation resulted in a significant reduction in symptomatic VTE (Fisher's exact test, two-sided P = 0.028) without bleeding complications; asymptomatic VTE, thrombocytopenia, HIT, HITT, death as a result of VTE, removal of CVC due to VTE, CVC-related infection and PTS were not assessed.Four cohort studies were included for the evaluation of adverse events. Three studies provided information on bleeding episodes: One participant developed an ischaemo-haemorrhagic stroke. One study provided information on other adverse events: None occurred.

AUTHORS' CONCLUSIONS

We found no significant effects of systemic treatments compared with no intervention in preventing (a)symptomatic VTE in paediatric oncology patients with CVCs. However, this could be a result of the low number of included participants, which resulted in low power. In one CCT, which compared one systemic treatment with another systemic treatment, we identified a significant reduction in symptomatic VTE with the addition of LMWH to AT supplementation.All studies investigated the prevalence of major and/or minor bleeding episodes, and none found a significant difference between study groups. None of the studies reported thrombocytopenia, HIT, HITT, death as a result of VTE, removal of CVC due to VTE, CVC-related infection or PTS among participants.On the basis of currently available evidence, we are not able to give recommendations for clinical practise. Additional well-designed international RCTs are needed to further explore the effects of systemic treatments in preventing VTE. Future studies should aim for adequate power with attainable sample sizes. The incidence of symptomatic VTE is relatively low; therefore, it might be necessary to select participants with thrombotic risk factors or to investigate asymptomatic VTE instead.

Do children with central venous line (CVL) dysfunction have increased risk of symptomatic thromboembolism compared to those without CVL-dysfunction, while on cancer therapy?

Background

Thromboembolism (TE) and infection are two common complications of central venous line (CVL). Thrombotic CVL-dysfunction is a common, yet less studied, complication of CVL. Two retrospective studies have reported significant association of CVL-dysfunction and TE. Recent studies indicate association of CVL-related small clot with infection. Infection is the most common cause of non-cancer related mortality in children with cancer. We and others have shown reduced overall survival (OS) in children with cancer and CVL-dysfunction compared to those without CVL-dysfunction. Despite these observations, to date there are no prospective studies to evaluate the clinical significance of CVL-dysfunction and it’s impact on the development of TE, infection, or outcome of children with cancer.

Study design

This is a prospective, analytical cohort study conducted at five tertiary care pediatric oncology centers in Ontario. Children (≤ 18 years of age) with non-central nervous system cancers and CVL will be eligible for the study. Primary outcome measure is symptomatic TE and secondary outcomes are infection, recurrence of cancer and death due to any cause. Data will be analyzed using regression analyses.

Discussion

The overall objective is to delineate the relationship between CVL-dysfunction, infection and TE. The primary aim is to evaluate the role of CVL-dysfunction as a predictor of symptomatic TE in children with cancer. We hypothesize that children with CVL-dysfunction have activation of the coagulation system resulting in an increased risk of symptomatic TE. The secondary aims are to study the impact of CVL-dysfunction on the rate of infection and the survival [OS and event free survival (EFS)] of children with cancer. We postulate that patients with CVL-dysfunction have an occult CVL-related clot which acts as a microbial focus with resultant increased risk of infection. Further, CVL-dysfunction by itself or in combination with associated complications may cause therapy delays resulting in adverse outcome.

This study will help to identify children at high risk for TE and infection. Based on the study results, we will design randomized controlled trials of prophylactic anticoagulant therapy to reduce the incidence of TE and infection. This in turn will help to improve the outcome in children with cancer.

Venous thromboembolism and adolescent and young adult oncology inpatients in US children's hospitals, 2001 to 2008

OBJECTIVES

To determine the frequency of venous thromboembolism (VTE) in the adolescent and young adult oncology population and the effects of age and cancer type on VTE, and to characterize adolescent and young adult oncology admissions at US children's hospitals.

STUDY DESIGN

We extracted data on oncology patients 15 to 24 years of age who were discharged from 35 hospitals in the Pediatric Hospital Information System (PHIS) between 2001 and 2008.

RESULTS

Of 9721 unique patients, VTE occurred in 511 (5.3%). An elevated OR of VTE occurred in patients 18 to 20 and 21 to 24 years of age (OR, 1.65; 95% CI, 1.36-2.00 and OR, 1.67; 95% CI, 1.21-2.32, respectively) compared with that in patients 15 to 17 years old. Patients with leukemia (OR, 5.53; 95% CI, 3.63-8.42) and bone/soft tissue sarcomas (OR, 4.32; 95% CI, 2.80-6.69) had a higher risk of VTE compared with patients with brain tumors. The number of adolescent and young adult oncology admissions to pediatric hospitals increased 31.9%, from 5409 admissions in 2001 to 7134 admissions in 2008.

CONCLUSIONS

Adolescent and young adult oncology patients, a growing population at pediatric hospitals, experience VTE as a common complication. Pediatricians should implement adolescent and young adult-specific studies to develop a standardized approach to preventing this adverse event.

Post-thrombotic syndrome in children: a systematic review of frequency of occurrence, validity of outcome measures, and prognostic factors

BACKGROUND

Post-thrombotic syndrome is a manifestation of chronic venous insufficiency following deep venous thrombosis. This systematic review was conducted to critically evaluate pediatric evidence on frequency of occurrence, validity of outcome measures, and prognostic indicators of post-thrombotic syndrome.

DESIGN AND METHODS

A comprehensive literature search of original reports revealed 19 eligible studies, totaling 977 patients with upper/lower extremity deep venous thrombosis. Calculated weighted mean frequency of post-thrombotic syndrome was 26% (95% confidence interval: 23-28%) overall, and differed significantly by prospective/non-prospective analysis and use/non-use of a standardized outcome measure.

RESULTS

Standardized post-thrombotic syndrome outcome measures included an adaptation of the Villalta scale, the Clinical-Etiologic-Anatomic-Pathologic classification, and the Manco-Johnson instrument. Data on validity were reported only for the Manco-Johnson instrument. No publications on post-thrombotic syndrome-related quality of life outcomes were identified. Candidate prognostic factors for post-thrombotic syndrome in prospective studies included use/non-use of thrombolysis and plasma levels of factor VIII activity and D-dimer.

CONCLUSIONS

Given that affected children must endure chronic sequelae for many decades, it is imperative that future collaborative pediatric prospective cohort studies and trials assess as key objectives and outcomes the incidence, severity, prognostic indicators, and health impact of post-thrombotic syndrome, using validated measures.

Thrombotic complications of tunneled central lines in children with malignancy

BACKGROUND

The total rate of thrombotic complications caused by tunneled central lines (TCL) is still not known, as are the long-term consequences.

AIM OF THE STUDY

Estimation of a rate of thrombotic complications in children with TCL and malignancy and Doppler ultrasound assessment of blood flow after TCL removal.

MATERIALS AND METHODS

One hundred twenty-four children were enrolled for the study. Heparin lock was used as a prophylaxis for line occlusion. The rate and type of thrombotic events associated with TCL were analyzed in all patients. In children without an earlier history of thrombosis, a Doppler ultrasound examination was carried out after TCL removal.

RESULTS

In 45.2% of patients at least 1 thrombotic event occurred. These events were TCL lumen thrombosis (42.8% of patients) and subclavian vein thrombosis (2.4% of patients). In 37 patients Doppler ultrasound was carried out and revealed an abnormal blood flow in the vein that was examined in 59.5% of them.

CONCLUSIONS

The total rate of thrombotic complications in children with TCL and malignancy is high. A substantial proportion of thrombotic complications can be clinically silent. The use of a heparin lock once a week seems far from effective in preventing thrombotic events in patients with TCL. The TCL life span has no influence on the rate of thrombotic events.

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.

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.

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.

Venous thrombosis in children with solid tumors

BACKGROUND

The prevalence of venous thrombosis (VT) in children with solid tumor and the role of different risk factors are not defined yet.

AIM

A cross-sectional observational study was conducted to evaluate the prevalence of both symptomatic and asymptomatic catheter-associated thrombosis events in children affected with different solid tumors.

METHODS

Patients with a solid tumor, admitted as day-care, were consecutively enrolled over a period of 10 months. All of them had a central venous line. Physical examination, D-dimer serum tests, and eco-color-Doppler ultrasonography were performed once at any time before catheter removal.

RESULTS

Forty-two patients (14 females and 28 males)-mean age 115 months-were evaluated. Five of the 42 patients (12%) had VT. In 4 of these, VT was catheter-related: 3 asymptomatic and 1 symptomatic. In the last patient, VT was clinically symptomatic and not catheter related. Patients with longer duration of catheter insertion presented with a higher rate of VT (P=0.05). Moreover, patients affected with neuroblastoma showed a higher rate of VT than the others with different solid tumors (P<0.05).

CONCLUSIONS

VT was visualized by echo-color-Doppler ultrasonography in 12% of the patients; it was asymptomatic in 7%. In our small series, VT was related to neuroblastoma disease and a longer duration of catheter insertion. Prospective and multicentric studies are required to select risk factors for VT in children with solid tumors.

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

Central venous catheters (CVCs) have improved the management of patients with cancer substantially, by facilitating chemotherapy and supportive therapy. The use of CVCs is associated with complications such as infection and upper-limb deep vein thrombosis (UL-DVT). The incidence of clinically overt UL-DVT related to the use of CVCs ranges between 2% and 4%. In the most recent study, the incidence of CVC-related thrombosis, as screened by venography, was approximately 18% in the absence of prophylaxis. In cancer patients with CVC-related UL-DVT, the incidence of clinically overt pulmonary embolism was between 15% and 25%, and the incidence of autopsy-proven pulmonary embolism was up to 50%. Pathogenic factors for CVC-related thrombosis include vessel injury caused by the CVC insertion procedure, venous stasis because of the indwelling CVC, and hypercoagulability associated with cancer. Recent studies have not confirmed a benefit for prophylaxis with antithrombotic agents for CVC-related thrombosis. The recommended treatment for CVC-related thrombosis is based on long-term anticoagulant therapy, with or without catheter removal.

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.

Thrombosis in children with malignancy

PURPOSE OF REVIEW

The association between thrombosis and malignancy in adults is well known. Children are now surviving malignancies that previously resulted in mortality. Complications, however, occur including thrombosis that result in mortality and morbidity. This review will explore the association in children and discuss the epidemiology and evidence-based diagnosis and treatment of thrombosis in this cohort.

RECENT FINDINGS

Thrombin is an important link between malignancy, metastases, and inflammation. The accurate diagnosis of thrombosis in the upper venous system is directly related to the diagnostic technique used. Antithrombotic treatment is challenging owing to higher risks of bleeding, for example, decreased platelet counts, tiffelitis, large vascular tumor, etc.

SUMMARY

Thrombosis and malignancy are associated in children. Properly designed studies are urgently required to further define the epidemiology of thrombosis in different malignancies and to find the best way to diagnose and treat thrombosis in children.

Evaluation of thrombotic children with malignancy

The purpose of this study was to evaluate inherited and acquired prothrombotic risk factors among children with malignancies who have thrombosis and emphasize the importance of inherited prothrombotic risk factors. Thirty-seven consecutive children with thrombosis and malignancy were included in this study. The patients were evaluated separately for time of development of thrombosis, insertion of a central venous line (CVL), history of L: -asparaginase usage, and recent infections. Prothrombotic risk factors such as factor V G1691A and prothrombin G20210A mutation, protein C, protein S, antithrombin III deficiencies, factor VIII and lipoprotein(a) elevation, and antiphospholipid antibodies were analyzed for all patients. Of 387 children with thrombosis, 37 (9.5%) had a malignancy. Thrombosis was detected in 9 patients at the time of diagnosis, during maintenance therapy in 25 patients, and after the discontinuation of treatment in 3 patients. One or two additional prothrombotic risk factors other than L: -asparaginase therapy and insertion of central venous lines were present in 20 of these patients (54%). It was found that eight patients had the factor V G1691A mutation in the heterozygote state. One of them had the factor V G1691A mutation associated with a history of infection and one patient had the factor V G1691A mutation associated with factor VIII elevation. One had the the prothrombin G20210A mutation in the heterozygote state, four had lipoprotein(a) elevation, two had factor VIII elevation, one had a decreased protein S level, one had a decreased protein C level, one had antiphospholipid positivity, and two had histories of infection. Malignancy is an important risk factor for the development of childhood thrombosis. However, the risk of thrombosis increases when accompanied by additional prothrombotic risk factors. For this reason, especially children with malignancy and at high risk for the development of thrombosis, such as those who have received L: -asparaginase or a replaced CVL during their therapy, might be screened for additional prothrombotic risk factors and appropriate measures might be taken to prevent the development of thrombosis.

Clinically evident venous thromboembolic events in children with brain tumors

We evaluated the incidence and significance of central venous access device dysfunction and symptomatic major thrombosis in 253 pediatric patients with brain tumors. Central venous access device dysfunction was a common complication (28.4%) and was associated with major thrombosis development and a reduced overall survival rate. Major thrombosis was relatively uncommon (2.8%).

Venous thromboembolism associated with long-term use of central venous catheters in cancer patients

Long-term central venous catheters (CVCs) have considerably improved the management of cancer patients because they facilitate chemotherapy, transfusions, parenteral nutrition, and blood sampling. However, the use of long-term CVCs, especially for chemotherapy, has been associated with the occurrence of upper-limb deep venous thrombosis (UL-DVT). The incidence of clinically overt UL-DVT related to CVCs has been reported to vary between 0.3% and 28.3%. The incidence of CVC-related UL-DVT screened by venography reportedly varies between 27% and 66%. The incidence of clinically overt pulmonary embolism (PE) in patients with CVC-related UL-DVT ranges from 15% to 25%, but an autopsy-proven PE rate of up to 50% has been reported. Vessel injury caused by the procedure of CVC insertion, venous stasis caused by the indwelling CVC, and cancer-related hypercoagulability are the main pathogenetic factors for CVC-related venous thromboembolism (VTE). Several studies have assessed the benefit of the prophylaxis of UL-DVT after CVC insertion in cancer patients. According to the results of these studies, prophylaxis with low molecular weight heparin or a low fixed dose of warfarin has been recently proposed. However, the limitations of the experimental design of the prophylactic studies do not allow definitive recommendations. The recommended therapy for UL-DVT associated with CVC is based on anticoagulant therapy with or without catheter removal. This review focuses on the epidemiology, pathogenesis, diagnosis, prevention, and treatment of VTE in cancer patients with long-term CVC.

Thrombotic complications of central venous catheters in children

Use of central venous catheters has become standard in the treatment of many chronic conditions during childhood and for the acute treatment of critically ill infants and children. However, these catheters can be associated with numerous complications, including thrombosis at the tip or in the lumen causing difficulty with its overall function. Even more concerning is the occlusion of large veins into which the catheter is placed, which could predispose patients to pulmonary embolism or postthrombotic syndrome. Recent research has focused on identifying risk factors for catheter-related thrombosis in children and determining methods for diagnosing deep venous thrombosis associated with a catheter in the upper extremities. Evidence now exists that as many as 50% of children with catheters develop deep venous thrombosis; however, most events are clinically silent. Few clinical trials have studied prevention of catheter-related thrombosis in pediatric patients. Data regarding incidence, treatment, and long-term outcome of catheter-related thrombosis in children are limited. Although central venous catheters are extremely important in the supportive care of sick children, concerns remain about their immediate and long-term safety.

Central venous line-related thrombosis in children: association with central venous line location and insertion technique

Venous thromboembolic events (VTEs) in children are associated with central venous lines (CVLs). The study objective was to assess whether CVL location and insertion technique are associated with the incidence of VTE in children. We hypothesized that VTE would be more frequent with (1). CVL location on the left body side, (2). CVL location in the subclavian vein rather than the jugular vein, and (3). CVL insertion by percutaneous technique rather than venous cut-down. This was a prospective, multicenter cohort study in children with acute lymphoblastic leukemia who had a CVL placed in the upper venous system during induction chemotherapy. Characteristics of CVL were documented prospectively. All children had outcome assessment for VTE by objective radiographic tests, including bilateral venography, ultrasound, echocardiography, and cranial magnetic resonance imaging. Among 85 children, 29 (34%) had VTE; 28 VTEs appeared in the upper venous system, and 1 was sinovenous thrombosis. Left-sided CVL (odds ratio [OR], 2.5; 95% confidence interval, 1.0-6.4; P =.048), subclavian CVL (OR, 3.1; 95% CI, 1.2-8.5; P =.025), and percutaneous CVL insertion (OR, 3.5; 95% CI, 1.3-9.2; P =.011) were associated with an increased incidence of VTE. Interaction occurred between CVL vein location and insertion technique. Subclavian vein CVL inserted percutaneously had an increased incidence (54%) of VTE compared with any other combination (P =.07). For CVL in the upper venous system, CVL placement on the right side and in the jugular vein may reduce the risk for CVL-related VTE. If subclavian vein placement is necessary, CVL insertion by venous cut-down appears preferable over percutaneous insertion.

Catheter-related thrombosis in children with cancer

OBJECTIVE

The prevalence of asymptomatic catheter-related thrombosis of the upper venous system in children with cancer has not been determined. We evaluated patients with cancer and implantable central venous catheters (ports) for this complication.

STUDY DESIGN

Children with cancer undergoing port removal were eligible for this study. Vessel patency was evaluated by contrast venography. We examined each child for physical stigmata of thrombosis and retrospectively assessed catheter-related mechanical difficulties and infections.

RESULTS

Thirty-one ports had been placed in 24 children (aged 20 months to 18 years; median age, 9 years) with diagnoses of leukemia/lymphoma (n = 10), solid tumor (n = 12), and histiocytosis (n = 2). Venography showed abnormalities in 12 of the 24 patients. Physical examination revealed dilated superficial veins on the chest in 3 patients. Venograms showed abnormalities in all 3 children with prominent superficial thoracic veins. Nine of the 21 other patients had clinically occult central venous occlusion.

CONCLUSION

Fifty percent (95% CI, 30% to 70%) of children who had implantable ports removed during or after treatment of cancer exhibited deep venous thrombosis at the site of catheter placement. Future studies should determine the contribution of inherited and other acquired risk factors for thrombosis and assess measures to prevent and/or treat catheter-related thrombosis in this population.