Purpose: To report a single-center experience with transcatheter embolization of type I endoleaks using the liquid embolic agent Onyx, an ethylene vinyl alcohol copolymer.
Methods: Eight patients (4 men; mean age 74.8 years, range 63-86) with 10 type I endoleaks (6 abdominal and 4 thoracic) diagnosed 2 days to 9 years after endovascular repair were treated with Onyx embolization because cuff extension was precluded by an insufficient landing zone in 6 cases and an unsuitable aortic diameter in 2. Endoleaks were accessed with a 4-F diagnostic catheter and a coaxially introduced dimethylsulfoxide-compatible microcatheter. Onyx-34 was predominantly applied due to its high viscosity; patent side branches were coil embolized prior to Onyx delivery in 3 cases.
Results: Technical success of the procedure was achieved in all cases. The mean volume of Onyx used for abdominal endoleaks was 11.8 mL (range 3.0-25.5) and 19.4 mL (range 4.5-31.5) for thoracic endoleaks. The average duration of the procedure was 76.7 minutes (range 34.5-110.6), and the average radiation dose area product was 18.8 cGy*cm (2) (range 10.6-55.8). Reperfusion of the endoleak was detected in one case 2 days after the procedure. A second case showed an occluded endoleak but a small trace of contrast between the aortic wall and the stent-graft. Non-target embolization was not found in any case. Mean follow-up was 13.2 months (range 8-24). The mean reduction in diameters for thoracic aneurysms after 6 and 12 months was 0.4 and 0.9 cm, respectively, and 0.6 and 1.2 cm, respectively, for abdominal aneurysms.
Conclusion: Transcatheter embolization of type I endoleaks using Onyx is a simple, safe, and sustainable treatment option with a high primary success rate for cases in which stent-graft extension is not possible. The benefit of additional coil embolization remains uncertain.