The Effect of Ovation Stent-Graft System on Aortic Pulse Wave Velocity: Preliminary Report on 3 Cases

The Ovation Aortic Stent-Graft System is based on a pair of polymer-filled inflatable O-rings to achieve sealing at the infrarenal level. However, this O-rings inflation has been associated with restriction of flow lumen and regional stenosis up to ∼60%. Since the aortic pulse wave velocity (aPWV) is considered a valuable marker of aorta stiffening we investigated the influence of the O-rings induced aortic lumen stenosis on the aPWV during the early postoperative period in a sample of 3 patients.

The internal cross-sectional area and the corresponding radius at the level immediately caudally to the renal arteries (Aupper and Rupper) and at the site of the inflated O-rings (Aint and Rint) was calculated from postoperative images of Computed tomography using dedicated software (3Mensio Medical Imaging B.V., Bilthoven, The Netherlands). Accordingly, the difference in the previously mentioned parameters between these areas was recorded. Noninvasive estimation of aPWV was conducted preoperatively and at 1-week and 1-month postoperatively with a brachial cuff-based automatic oscillometric device (Mobil-O-Graph; IEM, Stolberg, Germany).

Aupper was 286, 385, and 286 mm(2) for the 3 patients with Aint being 116, 86 and 95 mm(2), corresponding to inflow stenosis of 60%, 75%, and 66%, respectively. Accordingly, the radius reduction of the lumen between Rupper and Rint was 35%, 50%, and 60%. aPWV was kept quite constant for all patients 1-week and 1-month postoperatively, ranging 13.2-13.7, 11.4-11.5, and 8.3-8.6 m/sec, respectively.

The inflow restriction caused by the stiff, inflatable O-rings does not necessarily coincide with significant increase of aortic stiffness in the early postoperative period. Furthermore studies with more hemodynamic indices and longer follow-up are needed to delineate the impact of the Ovation's unique structural pattern on central hemodynamics.