Risk Factors and Possible Mechanisms of Superior Vena Cava Intravenous Port Malfunction

Objective: To identify the risk factors leading to catheter malfunction. Background: Reliable venous access is crucial for cancer patients. Malfunction of intravenous ports may lead to discontinuation of treatment and repeated interventions. We retrospectively reviewed the independent risk factors for catheter malfunction among patients receiving intravenous port implantations. Methods: A total of 1508 procedures were included from the calendar year 2006, and clinical data and chest plain films were analyzed. The patients were followed-up until June 30, 2010. For patients still alive, the last outpatient follow-up date was considered as the end point. For the remaining patients, the date of death or discharge against advice was considered as the end points. The risk factors for catheter malfunction were then evaluated. Results: The intervention-free periods of the malfunction group and non-malfunction group were 317 and 413 days, respectively. Statistical analyses showed that the Nut-Catheter Angle was the only risk factor for catheter malfunction (P = 0.001). A logistic model also confirmed that the Nut-Catheter Angle was the only risk factor for catheter malfunction (P < 0.001). Valve tip catheters were not advantageous with regard to catheter malfunction prevention as compared to open tip catheters. Conclusions: A smaller Nut-Catheter Angle had a greater risk for catheter malfunction. Catheter impingement caused by inadequate pocket creation and port implantation lead to compromised catheter lumen and difficulty flushing. The possibility of retained blood and medications increased thin thrombotic biofilm formation and medication precipitation. Catheter malfunctions can be avoided by using proper surgical techniques and adequate maintenance.