The compatibility of p-branch “off-the-shelf” fenestrated endovascular graft in Asian patients with juxtarenal aortic aneurysm

Abstract

The Zenith pivot branch (p-branch) fenestrated endovascular graft (Cook Medical, Bloomington, Ind) is a new "off-the-shelf" device to treat patients with juxtarenal aortic aneurysms (JRAs). Two options are currently available, which appear to suit >70% of white patients. This study investigates the anatomic applicability of the p-branch fenestrated graft in a cohort of Asian patients with JRA. Computed tomography images of 51 consecutive Asian patients with JRA (43 men; mean age, 76.8 years) were analyzed on an Aquarius workstation (TeraRecon, San Mateo, Calif) and matched to two current configurations of the p-branch (options A and B: single superior mesenteric artery [SMA] and two renal fenestrations, and a celiac axis scallop). With use of the SMA as reference, the anatomic positions of both renal arteries and the celiac axis were figured together with their diameters on a template generated on MATLAB (MathWorks, Natick, Mass), and then they were matched with two graft configurations. The renal artery origins were assessed for three classes of "closeness of fit" based on diameter: perfect match, marginal match, and mismatch, respectively, defined as the renal artery origins being located entirely inside, partially inside, and completely outside their corresponding fenestrations. The suitability of the p-branch graft design to the aneurysms was then evaluated. A total of 31 JRA patients (60.8%) were regarded as suitable candidates for one or both p-branch stent grafts (20 with option A, 22 with option B, and 11 with both options). In 35 patients (68.6%), both renal arteries could be aligned with the fenestrations. Among them, 16 patients (31.4%) were perfectly matched, whereas 19 patients (37.2%) were only marginally suitable. The major reason for exclusion was the misalignment of the renal fenestrations. In 16 patients with unsuitable renal fenestrations, 8 were attributed to the right renal origins being located too distally compared with their corresponding fenestrations. Another reason for exclusion was the position of the celiac axis scallop in four patients (7.84%), and insufficient aortic length for the graft was encountered in another four. If the right renal fenestration of option B was adjusted to 20 mm caudal to the SMA fenestration (level with the left fenestration), the match of renal fenestration could reach 78.4% (40 of 51). The present design of the p-branch off-the-shelf fenestrated graft is feasible for a good proportion of JRA patients in Asia. Further refinement of design may improve the anatomic match, especially a lower right renal artery origin.