03:00 PM Abstract No. 93 Venous stenosis large animal model utilizing endovenous radiofrequency ablation

Abstract

To investigate the feasibility of creating a venous stenosis animal model using endovenous radiofrequency ablation. Two adult swine were used with IACUC approval. After heparinization, a ClosureFast RF endovenous catheter (Medtronic, MN) was used for ablation in 40-second intervals in iliac and jugular veins with interval venography until > 80% stenosis was achieved. External manual compression was applied from the ventral surface during ablation to collapse the vein around the catheter. Angioplasty was performed using an 8mm balloon (Medtronic, MN). A 12mm x 3cm Wallstent (Boston Scientific, MA) was deployed in the stenosis followed by 12mm balloon angioplasty. Interval venography was used to visualize and record the stenosis response during angioplasty and stent deployment. Stenoses of > 80% (1st animal: 85.2% right, 85.0% left; 2nd animal: 82.8% left) without thrombosis were achieved in the iliac veins after a maximum of 7 cycles of 40-second endovenous radiofrequency ablation. Angioplasty of each stenosis with a balloon matching the native diameter resulted in reduction of the mean venous stenosis to 63.3% in the iliac veins despite achieving nominal diameter of the balloon, representing an elastic response of the stenosis as seen clinically. After Wallstent deployment, the iliac vein diameter peripheral to the stent edge reduced from a mean of 11.4 mm to 10.4 mm, also representing a clinical biomechanical effect described during treatment of venous stenoses. Experimentation in the right jugular vein demonstrated similar results. Stenosis of 83.4% was achieved after 2 cycles of endovenous radiofrequency ablation. Balloon angioplasty to nominal diameter showed an elastic response with mean residual venous stenosis of 43.7%. Endovenous radiofrequency ablation is a feasible method for creating an elastic venous stenosis in porcine vein. Further investigation with histology and survival study to recapitulate a more biologically relevant scenario is warranted. If validated, this model can be established as an efficient in vivo platform for development and assessment of venous-specific vascular devices.