Results from a prospective multicenter feasibility study of Zenith p-Branch stent graft

To evaluate the Cook Zenith p-Branch stent graft (William A. Cook Australia, Brisbane, Queensland, Australia) for the treatment of patients with asymptomatic juxtarenal or pararenal abdominal aortic aneurysms in a prospective, nonrandomized, multicenter, feasibility study conducted in the United States.

The off-the-shelf p-Branch endograft incorporates a celiac scallop, superior mesenteric artery (SMA) fenestration, and two conical-shaped pivot renal fenestrations. Patients were eligible if the aneurysm did not extend above the distal margin of the SMA and the anatomy of renal and visceral arteries were compatible with one of the two p-Branch configurations (configuration A, renal fenestrations at the same longitudinal position; configuration B, offset renal fenestration).

A total of 30 patients (93% men; mean age, 73 years; mean aneurysm diameter, 64.7 ± 11.4 mm) were enrolled from January 2013 to June 2015. The mean follow-up period was 28.7 ± 12.5 months (as of October 2017). The technical success rate was 93% (28/30), with technical failure occurring in the first two study cases (device deliberately repositioned below the renal arteries because of difficulty in cannulating the renal arteries in one and an inability to place a renal stent in the other; both patients survived the procedure and withdrew from the study before the 12-month follow-up visit). No additional technical failures occurred after these first two cases, when an updated physician training and proctoring program was implemented. No 30-day mortality occurred. Of the remaining 28 patients, three died during the follow-up period; none within 30 days and none related to the device or procedure as determined by Clinical Events Committee adjudication. No treated aneurysm ruptures, conversion, or core laboratory-reported migration, or stent fracture were reported. The primary renal artery patency (interval to occlusion or reintervention for stenosis) rate was 88.6% ± 4.4% at 1 and 2 years. Two patients (7%) developed renal insufficiency secondary to a right renal artery stenosis in one patient and progression of chronic renal insufficiency in one patient. No patient required dialysis or developed mesenteric ischemia. Of the 28 patients, nine (32%) had undergone 13 secondary interventions for renal artery occlusion (n = 2), SMA occlusion (n = 1), renal or SMA stenosis (5 interventions in 4 patients), renal stent kinking (n = 1), lower extremity claudication (n = 2 in the same patient), type III endoleak between the p-Branch and renal stent (n = 1), and type II endoleak (n = 1).

These early and intermediate results, which incorporated physician learning curves, support the safety and feasibility of the off-the-shelf Zenith p-Branch device. Follow-up examinations through 5 years will continue to assess the long-term results.