Initial Clinical Experience with Shape Memory Polymer Plugs for Various Venous Embolization

Shape memory polymer plugs are novel, porous, self-expanding embolic devices that promote homogeneous thrombus formation with minimal imaging artifacts. Although increasingly used in arterial procedures, clinical data on venous applications remain limited. This technical note describes our initial experience with shape memory polymer plugs for multiple types of venous embolization and details the procedural techniques used to optimize outcomes.

Five patients underwent venous embolization using shape memory polymer plugs. Indications included a pelvic arteriovenous malformation outflow vein, pelvic congestion syndrome, gastric varices treated with balloon-occluded retrograde transvenous obliteration, and a congenital portosystemic shunt. Delivery systems included 5-F or 6-F guiding sheaths or a 9-F balloon catheter. Technical modifications included partial deployment, a 5-minute dwell time, anchoring using Amplatzer vascular plugs, temporary balloon protection, and adjunctive sclerosant administration.

A total of 15 shape memory polymer plugs were deployed. Technical success was achieved in four of five cases. No plug migration occurred. One portosystemic shunt case showed persistent residual flow due to a size mismatch between the 12-mm shape memory polymer and the 10.5-mm vessel. Clinical improvement occurred in all patients. Follow-up (1-30 months) demonstrated durable occlusion in successful cases, confirmed by computed tomography with minimal artifact.

Shape memory polymer plugs may be a feasible option in selected venous embolization cases. Their large occlusive volume, low radial force, and radiolucency offer procedural and imaging advantages. Device size limitations and anchoring requirements must be considered. Further studies and larger device options are needed.