To assess the pullout force (POF) of bridging stent-grafts used in thoracoabdominal stent-grafts and iliac bifurcated grafts.
In an experimental setup, the POFs of Viabahn or Fluency with or without a Zilver stent were measured when deployed into the renal and celiac branches of a Zenith thoracoabdominal cuff-bearing branched stent-graft. The POFs of the Atrium i-Cast, Viabahn, Fluency, and Fluency+Zilver were measured when deployed into an iliac bifurcated graft with a short side-branch for the internal iliac artery. At least 10 trials were performed for each stent in air at room temperature.
The median POF (IQR; absolute range) required to dislodge each bridging stent-graft from the 6-mm renal branch was 1.89 N (0.47 N; 1.65-2.5) for the 7-mm Viabahn, 1.17 N (0.39 N; 0.68-1.57 N) for the 7-mm Fluency, and 2.08 N (0.49 N; 1.59-2.62 N) for the 7-mm Fluency with a supporting 8-mm Zilver stent (p<0.001).
There is a small but significant difference in pullout forces among various bridging stent-grafts. As pullout forces may be one factor contributing to type III endoleaks in complex endovascular repairs involving fenestrated and branched stent-grafts, further study is warranted to compare these grafts clinically to determine if they perform differently. According to this study, the theoretical advantages associated with the Viabahn stent-graft make it a strong choice for minimizing branch dislocations.