Aetiology and management of persistent withdrawal occlusion in venous ports in oncology patients.

Introduction: Persistent withdrawal occlusion (PWO) is a specific catheter malfunction characterized by the inability to withdraw blood through the device. The most common cause of PWO in ports is the presence of a fibroblastic sleeve (FS). If malfunction occurs, medication can be applied incorrectly with the increased risk of complications.

Methods: One hundred seventy-seven cases of PWO in venous ports were managed. We focused on evaluating the cause of PWO, the frequency of occurrence of FS, and the options to address the malfunction. The patients underwent fluoroscopy with a contrast agent administration. Mechanical disruption (MD) with a syringe of saline using the flush method was used; in case of its failure, subsequent administration of a lock solution with taurolidine and urokinase, or low-dose thrombolysis with alteplase was indicated. Demographic data were compared with a control group.

Results: A significantly higher proportion of female patients was found in the cohort of patients with PWO (80.3% vs 66.3%, p = 0.004), dominantly patients with ovarian cancer (12.8% vs 4.8%, p = 0.022). No effect of the cannulated vein or the type of treatment on the incidence of PWO was demonstrated. The presence of FS was verified in 70% of cases. MD with a syringe was successful in 53.5% of cases. A significantly shorter time to referral (3 weeks) was demonstrated with successful management. The overall success rate of achieving desobliteration by MD alone or in combination with a thrombolytic (urokinase or alteplase) administration was 97.4%.

Conclusion: We created a method for resolving PWO using MD +/- application of thrombolytics with 97.4% success rate. Current evidence showed that FS is not likely to be affected by thrombolytic drugs; however, we have ascertained an effect of these drugs, proposing a hypothesis of microthrombotic events at the tip of the catheter if fibroblastic sleeve is present.