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Introduction
Branched and fenestrated endovascular repair of arch and thoracoabdominal aortic pathology is emerging as a feasible option in a growing number of patients. However, the long-term durability of endovascular side branches remains a concern, and little data exists to allow comparison to open repair branch patency. As such, the purpose of this study was to examine long-term patency of side branches in open aortic arch and thoracoabdominal repair to provide gold-standard data for subsequent comparisons to endovascular repair.
Methods
Retrospective analysis of a prospectively-maintained database was performed for all patients undergoing open bypass of arch or visceral vessels at a single institution between 07/2005 and 04/2013. Only branch vessel bypasses originating from the native aorta, including the common iliac arteries, or an aortic graft were included. Reports from all computed tomography angiography (CTA) scans were reviewed, and incidences of branch graft occlusion collected. Personal review of all CTA images where occlusion was reported was performed to confirm the original interpretation. A time-to-occlusion analysis using Kaplan-Meier curves was performed for individual vessels.
Results
213 procedures in 196 patients were identified. Of these, 162 procedures (149 patients, 76.1%) had post-operative CTA imaging studies, including 437 total bypassed vessels (Table 1). Dacron was used for 95.7% of all grafts. Although the majority of procedures were aortic arch procedures (53.7%, n = 87), fewer total arch vessels were bypassed (n = 191, 43.7%). Median length of follow-up for all procedures was 393 days (range: 2 days - 7.6 years). A graft limb occluded in 15 patients (10.1%), with 16 total bypass grafts occluded (3.7%). The median time-to-occlusion was 36 days (range: 11 days to 2.1 years), and all occluded grafts were Dacron. Most occluded grafts were to either the left (7/17, 41%) or right (6/17, 35%) renal artery. Of the 12 patients with an occlusion of their renal artery graft, six had acute renal failure (>2-fold increase in creatinine from baseline), and three required new-onset dialysis, although this was not permanent in any patient. The one patient with an SMA occlusion died due to small bowel necrosis. Overall 1, 3, and 5-year primary patency rates were 95.7%, 94.9%, and 94.9%, respectively, with renal artery bypasses having a significantly lower long-term patency rate than non-renal artery bypasses (p < 0.0001, Figure 1).
Conclusion
Long-term branch graft patency after open aortic arch or visceral vessel bypass is excellent. The increased incidence of occlusion for renal artery grafts may be due to the typically smaller and more frequently diseased nature of the renal arteries, and ways of decreasing the likelihood of occlusion should be evaluated. These data should serve well as a source of comparison for branch endograft patency following branched and fenestrated endovascular aortic repair.

Table 1

Procedure Performed
Open total arch	37 (22.8%)
Hybrid arch	40 (24.7%)
Thoracoabdominal aortic aneurysm repair (open & hybrid)	76 (46.9%)
Other bypass procedure	9 (5.6%)
Total	162 (149 patients)
Vessels Bypassed
Arch Vessels	191 (43.7%)
Innominate (including bovine)	73 (16.7%)
L common carotid	75 (17.2%)
R common carotid	9 (2.1%)
L subclavian	27 (6.2%)
R subclavian	7 (1.6%)
Visceral Vessels	246 (56.3%)
L renal artery	67 (15.3%)
R renal artery	58 (13.3%)
SMA	62 (14.2%)
Celiac	59 (13.5%)
Total	437