Comparison of supra-arch in situ fenestration and chimney techniques for aortic dissection involving the left subclavian artery.

INTRODUCTION: Endovascular intervention involving the aortic arch, particularly in thoracic aortic dissection, remains challenging and controversial at current time when there is no commercially suitable grafts on most of the international markets. This study compared two endovascular treatments that maintain left subclavian artery perfusion using two modified techniques for type-B aortic dissection patients.
METHODS: Consecutive cases utilizing chimney or in situ fenestration techniques to preserve left subclavian artery in type B AD from 2006 to 2015 in our single institution were retrospectively reviewed. Statistical analyses were performed with Student t-test, Wilcoxon rank sum, and Fisher exact tests when appropriate. Significant statistical differences were determined with p < 0.05.
RESULTS: A total of 85 cases, including 67 (79.8%) with chimney and 18 (21.2%) with in situ fenestration techniques were identified in this retrospective study. In chimney group, there were 18 (26.9%) acute, 29 (43.3%) sub-acute, and 20 (29.9%) chronic aortic dissections. We implanted 24 Zenith and 43 Talent aortic endografts along with 55 balloon-expandable bare stents and 12 self-expanding covered stents in chimney group. Whereas in in situ fenestration group, there were four (22.2%) acute, six (33.3%) subacute, and eight (44.5%) chronic aortic dissections, all of which received Zenith endografts with 11 balloon-expandable covered and seven self-expanding covered stents, respectively. Demographic variables were similarly distributed with 100% intraoperative technical overall success in both groups. Comparing to in situ fenestration group, chimney group has shorter procedural and fluoroscopy time, less blood loss, and contrast volume used. All patients were followed-up to 52 months (median 38, range 24-52). Overall group mortality is 3.6% (3/84). All deaths were from chimney group. There was no procedure-related stroke observed within the study series. Primary patency was maintained while aortic remodeling with complete false lumen was achieved in all patients except that there were three (4.55%) Type-I endoleak cases in early post-operative period and one (1.5%) stent compression at 3-months follow-up in chimney group. There were no stent-related complications observed in in situ fenestration group.
CONCLUSION: Although there were previous studies describing the similar techniques, this study appears to be the first study to compare in situ fenestration and chimney techniques for aortic dissection involving the left subclavian artery according to the MEDLINE search. Although we are unable to establish the superiority between two approaches due to small sample size and relative short period of follow-up, in situ fenestration may represent a more favorable option, especially among aortic dissections with short proximal landing zones in the study.