Initial experience with polymer endovascular aneurysm repair using the Alto stent graft

Abstract

The Alto Abdominal Stent Graft System (Endologix Inc, Irvine, Calif) is the next-generation Ovation system for polymer endovascular aneurysm repair. The most significant design change relocates the sealing ring closer to the top of the fabric, but a number of additional design changes were made. This report describes the first seven patients treated with the Alto stent graft at a single center (Auckland Hospital, Auckland, New Zealand) from August 2016 to February 2017. There was 100% procedural technical success. At 12-month follow-up, no type I or type III endoleak, stent graft migration, abdominal aortic aneurysm rupture, abdominal aortic aneurysm-related mortality, or secondary intervention was reported.

Keywords: Alto; Aortic aneurysm; EVAR; Endovascular; Ovation; Stent graft.

Fig 1

Comparison of Ovation Alto (left) and Ovation iX (right). Relative to the proximal stent graft edge represented by the blue horizontal line, the midpoint of the proximal sealing ring is 7 mm distal with Ovation Alto vs 13 mm distal with Ovation iX.

Fig 2

New device features of Alto. 1, Mid-crown segment of proximal fixation stent. 2, Sealing ring center 7 mm from the proximal polytetrafluoroethylene edge. 3, Radiopaque markers mark upper aspect of endograft fabric. 4, Integrated balloon. 5, Webbing at graft bifurcation. 6, Offset AB legs in endograft.

Fig 3

Initial deployment steps of the Alto device. Endoluminal repair performed in a 74-year-old woman with a solitary functional right kidney. A right main renal artery stenosis was treated with a stent at the beginning of the endoluminal procedure. A, Device introduced. A calibrated pigtail catheter has been introduced from the contralateral groin for angiographic control. Note the following features: 1, “exclamation mark” configuration of the radiopaque markers on the delivery system marks the position of the contralateral limb; 2, radiopaque markers on the base of the proximal fixation stent; 3, upper radiopaque marker of the integrated compliant balloon; 4, right renal stent. B, Deployment of the mid-crown segment of the proximal fixation stent. Note that this is deployed while the device is above the planned landing zone. Appropriate angulation of the image intensifier is performed to superimpose the eight upper fabric radiopaque markers (left). Compliant balloon is partially inflated to expand the mid-crown segment (right). C, Endograft is repositioned caudally so that endograft material lies immediately below the renal stent (left). Proximal, uncovered fixation stent is fully deployed (right). D, Sealing and limb rings are filled with polymer. Note that the top radiopaque marker of the integrated compliant balloon accurately marks the center of the sealing ring (left). Integrated compliant balloon is used to postdilate the main body (right). E, Completion angiography.

Fig 4

Ovation Alto repair of an aneurysm with a heavily calcified and mildly angulated infrarenal neck. A, Axial and coronal images from the preoperative computed tomography scan. B, Axial and coronal images from a 1-month postoperative computed tomography scan.