Central Venous Catheters and Venous Thrombotic Events in Pediatric Oncology Patients: A Multicenter Case Control Study

Central venous catheters (CVCs) have greatly improved the delivery of systemic chemotherapy to pediatric oncology patients and have significantly improved their quality of life. However, CVCs can cause serious venous thrombotic events (VTE), necessitating anticoagulation, CVC removal and reinsertion. There is paucity of data on clinical manifestations and impact of CVC associated VTE in pediatric cancer patients. In this study we describe the clinical presentation and impact of VTE on CVCs.

We performed a multi-center case-control study in childhood cancer survivors. Survivors who experienced a symptomatic VTE during their therapy, and survivors who did not experience VTE (controls) were recruited. Additionally, controls in whom an asymptomatic VTE was detected were assessed separately. Data on location and number of CVCs and of VTE was analyzed. CVCs were categorized by method of insertion and included totally implanted devices (TID) such as ports, tunneled lines (TL) and peripherally insertion central catheters (PICC).

Seventy-seven survivors with a history of symptomatic VTE, 10 with asymptomatic VTE, and 178 controls were recruited (Table 1). The mean number of CVCs per individual cases and controls was 1.64±0.91 and 1.12±0.55, respectively (p=0.0001). In cases and controls, 44% and 12.3%, respectively, had >1 CVC (p=0.0001). In patients with asymptomatic VTE the mean number of CVCs per individual was 1.8±1.03 (p=0.069, tending towards significance as compared to controls); 50% had >1 CVC.

Among cases with symptomatic VTE, right subclavian (RSCV) (35.1%), left subclavian (LSCV) (16.9%) and right internal jugular (RIJ) (14.3%) veins were the most common CVC sites. In controls, corresponding percentages were 32.6%, 20.8% and 9.6%, respectively. In patients with asymptomatic VTE, RIJ (40%) and RSCV (20%) were the most frequent CVC sites.

TID, TL and PICC were used in 60.7%, 22.5% and 2.3% of the controls, respectively. The corresponding numbers in symptomatic VTE cases were 52%, 22.1% and 11.7%, respectively. The difference in distribution of CVCs in the 2 groups was statistically significant (p=0.017). TID were used more frequently in controls (60.7%) as compared to symptomatic VTE (52%) patients. Central venous catheters were inserted into the right-sided veins in 57.9%, 65% and 80% of the controls, symptomatic and asymptomatic VTE cases, respectively.

Forty-nine patients had central venous VTE (CVVTE). CVC dysfunction (46.9%), swelling (34.7%) and pain (14.3%) were the most common symptoms of CVVTE. TID, TL and PICC were used in 50%, 34.8% and 6.5%, respectively, of the patients with CVVTE. Concordance in the location of CVC and CVVTE was seen in 27 (55.1%) cases. The most common sites of CVCs in these 27 patients were RIJ (25.9%), RSCV (25.9%) and LSCV (18.5%).

In this cohort of pediatric cancer survivors, we made several novel observations indicating significant clinical impact of both symptomatic and asymptomatic VTE. The type of CVC used varied significantly between cases and controls. Use of TID appears protective, plausibly due to relatively shorter length of the central line (compared to other CVCs), non-exposed parts, and use of only non-coring needles to access the device.

A concordance of over 50% in the location of CVCs and that of CVVTE was observed and has not previously been reported. These observations are of importance in identification of pediatric oncology patients at higher risk of CVC related complications. These observations can inform the design of appropriate preventive and therapeutic interventions in pediatric oncology patients who will continue to require CVCs.

No relevant conflicts of interest to declare.