Print this pagePrediction Of Altered Endo-Graft Deployment During AAA Repair With the Gore Excluder
1Dartmouth Hitchcock Medical Center, Lebanon, NH;2Medical Media Systems, West Lebanon, NH
Objective: During endovascular AAA repair (EVAR), the rapid deployment of the Gore Excluder endograft has been associated with anatomic shortening of the endograft path. We studied clinical results with this endograft to develop a mathematical algorithm to predict the alteration in anatomy during deployment.
Methods: Pre-operative planning was based on CT scans with 3-D computer-aided measurement and virtual graft simulation. Pre- and post-operative CT scans were evaluated for 50 consecutive patients with Gore Excluder endografts. Tortuosity was quantitated in several ways.
Results: The endograft was deployed successfully in all cases. The graft endpoints were close to the preoperative plan: renal-artery-to-graft distance was within 2.2 ± .5 mm, limb endpoint to hypogastric origin was within 2.4 ± 1.3 mm. Although typically accurate, the graft deployment path differed from pre-op by up to 3 cm. The hypogastric artery was unintentionally covered 3 times (3%) in 2 patients. Key determinants of deployment path alterations were: 1) aorto-iliac tortuosity (p<.02), 2) the insertion side (73% of alterations more than 10 mm were ipsilateral to the main device (p<.05) and 3) the degree of planned graft rotation (74% of cases altered <5 mm were in the standard position, p<.05). We subsequently developed an algorithm to predict the risk of alteration of the graft path by group (e.g., 0% of the low risk group vs. 30% of the high risk group experienced >20 mm shortening, p<.007) and to predict the degree of alteration of the anatomy (none shortened >11 mm more than predicted).
Conclusions: In a minority of Gore Excluder endograft cases, the deployment path will be significantly altered, but these instances can result in problems. Anatomic shortening is predictable on the basis of preoperative morphologic features. We developed an algorithm that quantitates the risk and degree of shortening associated with endograft deployment.