Purpose: To describe variations in the shape, orientation, and length of the branches of multi-branched thoracoabdominal stent grafts.
Method: The branches were constructed in situ by attaching a covered stent (Fluency Plus Tracheobronchial Stent Graft; Bard Peripheral Vascular, Tempe, Ariz) to each of four caudally-oriented cuffs on custom-made stent grafts. Pre- and postoperative computed tomography (CT) scans of 38 consecutively treated patients were analyzed using a three-dimensional work station to give the orientation of celiac, superior mesenteric, and right renal and left renal orifices relative to the centerline of the aorta (planned cuff orientation [PCO]) and relative to the centerline of the stent graft (actual vessel orientation [AVO]). The orientation of each cuff (actual cuff orientation [ACO]) was also measured relative to the centerline of the stent graft. These values were used to assess the degree of stent graft malorientation (ACO-PCO), or cuff-to-artery misalignment (ACO-AVO), and combined with measurements of branch length to calculate the resulting lateral displacement (arc distance [AD]) between each cuff and its corresponding arterial orifice and the angle (longitudinal branch angulation [LBA]) between the long axis of the branch and the long axis of the aorta, all in the plane of the aortic surface.
Results: All 136 branches were inserted as intended. None has since migrated, disconnected, or kinked. In most cases, stent graft orientation was accurate, with a mean ACO-PCO of 18.4 + 12.1 degrees. Cuff-to-artery misalignment was correspondingly low, with a mean ACO-AVO of 19.8 + 14.0 degrees. More than 30 degrees of misalignment was present in 23.2% of branches, yet only 9% (n = 12) had an LBA of >30 degrees.
Conclusion: Moderate degrees of cuff-to-artery misalignment had no effect on the feasibility of multi-branched stent graft insertion.