Multicenter pivotal trial results of the Lifepath System for endovascular aortic aneurysm repair

Abstract

Purpose: This study was undertaken to assess the results of endovascular aortic aneurysm repair with the Lifepath abdominal aortic aneurysm (AAA) graft system.

Method: In a prospective clinical trial, 23 centers used the Lifepath System balloon-expandable, modular bifurcated stent graft for elective endovascular aortic aneurysm repair. Stent grafts were sized according to computed tomographic angiography-based diameter measurements. All repairs were performed in the operating room through bilateral surgically exposed femoral arteries. Results were assessed with contrast agent-enhanced computed tomography scans and plain abdominal x-ray films at 1, 6, 12, 24, 36, and 48 months postoperatively.

Results: Over 52 months (mean follow-up, 11 months), 227 patients (206 men, 21 women) were enrolled. Technical implant success rate was 98.7%. There were five (2.2%) conversions to open surgery: two emergently because of aortic perforation; to treat refractory endoleak, immediate in one and at 12 months in one; and to replace a device with wireform fractures that had migrated at 12 months, resulting in a proximal endoleak. The perioperative mortality rate was 1.3%. There was one operative death during a secondary procedure to repair perforation of the aorta. There were two perioperative deaths, from postoperative myocardial infarction (n = 1) and pulmonary embolus (n = 1). There were 12 late deaths, from coronary artery disease (n = 4), cancer (n = 2), respiratory failure (n = 2), sepsis (n = 1), or unknown cause (n = 3). Median length of stay was 2 days (mean, 4 days). There have been no AAA ruptures after successful implantation of the device, no graft limb thromboses, and no limb dislocations. At the time of operation endoleak was noted in 43 (19%) patients, but by 6 months this was reduced to 8 (5.9%) patients (type I, n = 1; type II, n = 7). There were no type III or type IV endoleaks. Secondary interventions to treat endoleaks included open conversion (n = 2), placement of extension cuffs (n = 4), repeated balloon dilation (n = 3), and coil embolization (n = 6). The two remaining secondary interventions were emergent treatment of postoperative bleeding from a groin incision, and a colon resection because of postoperative colonic ischemia, for a 12-month secondary intervention rate of 7.5%. Wireform fractures were noted in the first generation Lifepath device in 37 of 79 (47%) patients. Graft migration (>10 mm) was observed in five patients (2.2%), each of whom also had two or more fractures of the proximal anchoring wireforms. Migration resulted in a proximal attachment endoleak in one patient. In response to wireform fractures, the device was modified after the initial 79 patients were enrolled. Wireform fracture has been observed in six patients since this modification (4%), and in only one patient did this involve fracture of a proximal anchoring wireform; none of these patients has had endoleak or graft migration. By 12 months, mean aneurysm diameter was noted to decrease by 9 mm (P <.0001), and mean aneurysm volume by 42 mL (P <.0001) from the preoperative visit.

Conclusion: The Lifepath System demonstrates a low endoleak and secondary intervention rate and high sac regression rate, compared with other devices. The unique balloon-expandable design offers the advantages of precise placement and high radial force. The device appears to be highly resistant to limb thrombosis and modular component separation. Patients were protected from AAA rupture after successful device implantation, and demonstrated significant reduction in AAA diameter and volume. Fractures of the wireforms of the main body of the device have been observed. Careful long-term follow-up is necessary.