The chimney graft technique for preserving visceral vessels during endovascular treatment of aortic pathologies.

Objective: Patients with juxtarenal, pararenal, or thoracoabdominal aneurysms require complex surgical open repair, which is associated with increased mortality and morbidity. The "chimney graft" or "snorkel" technique has evolved as a potential alternative to fenestrated and side-branched endografts. The purpose of this study is to review all published reports on chimney graft (CG) technique involving visceral vessels and investigate the safety and efficacy of the technique.
Methods: Studies were included in the present review if visceral revascularization during endovascular treatment of aortic pathologies was achieved via a CG implantation. Reports on the chimney technique for aortic arch branches revascularization were excluded. A multiple electronic health database search was performed on all articles published until April 2011.
Results: The electronic literature search yielded 15 reports that fulfilled the inclusion criteria. A total of 93 patients (81.3% male; mean age, 71.9 ± 0.9 years) were analyzed. In 77.4% of the patients, the CG procedure was applied for the treatment of abdominal aortic aneurysms. Out of the 93 patients, 24.7% were operated on in an urgent setting (symptomatic or ruptured aneurysm). A total of 134 CGs were implanted: 108 to the renal arteries, 20 to the superior mesenteric artery, five to the celiac trunk, and one to the inferior mesenteric artery. In 57 patients, a single CG was deployed; in 32 patients, two CGs; in three patients, three CGs; and in one patient, four CGs were deployed. Ninety-four percent of CGs were directed proximally, whereas 6.0% were directed caudally. Primary technical success was achieved in all patients. A total of 13 patients (14.0%) developed a type I endoleak. Three were detected and treated intraoperatively. Postoperatively, 10 type I endoleaks were revealed, four of which required secondary intervention. During a mean follow-up period of 9.0 ± 1.0 months, 131 of 134 (97.8%) CGs remained patent. Two CGs to the renal arteries and one to the superior mesenteric artery occluded. Postoperatively, 11.8% of patients suffered renal function impairment and 2.1% a myocardial infarction. Ischemic stroke presented in 3.2% of patients. The 30-day in-hospital mortality was 4.3%.
Conclusions: The role of the chimney technique in the management of complex abdominal aortic aneurysms is still unclear. This technique has relatively good results, considering the anatomic limitations of the aortic neck. However, long-term endograft durability and proximal fixation remains a significant concern. Thus, there is a reasonable hesitation to embrace the method for widespread use in the absence of long-term data.
(Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)