Chimney Grafts in Aortic Stent Grafting: Hazardous or Useful Technique? Systematic Review of Current Data.

BACKGROUND: The chimney graft (CG) technique was introduced to rescue accidentally covered aortic branches during aortic endovascular repair. It extends the sealing zone. There is concern about "gutter" type I endoleak (EL-I) and about the durability of CGs. The aim of the present report was to analyze the rapidly increasing existing data. METHODS: A search was performed (PRISMA criteria) for all studies of visceral and thoracic/arch chimney grafts. Technical and clinical details and outcome were assessed. RESULTS: The present review includes 831 patients who underwent EVAR/TEVAR (endovascular aneurysm repair/thoracic endovascular aneurysm repair) with one or more chimney, periscope, or sandwich grafts. For aortic visceral vessels 517 patients received 911 visceral CGs and 314 patients received 364 arch CGs. Most procedures (81% visceral and 69% arch CGs) were elective. Thirty day mortality was 4% for both groups. The rate of early EL-I was 13% (visceral CGs) and 11% (arch CGs). Most EL-I were handled conservatively (observation: 70% for visceral CG and 45% for arch CG). Early CG patency was high (97-99%) and remained high during follow up (median 17 months). Late (after 30 days) EL-I was reported in nine visceral (2%) and 12 arch (4%) CG cases. Few other late complications were reported, but those losing a kidney at the initial repair seemed to have a high risk of requiring permanent hemodialysis. CONCLUSION: Increasing amounts of data support the benefit of visceral and arch chimney graft techniques. In particular, the low early mortality and complication rates and high long-term patency seem advantageous; however, the majority of cases have been treated electively, and there is a high risk of bias in all studies. Mid- to long-term data suggest few late complications, except in cases where one renal artery was sacrificed. The CG technique is valuable for complex urgent patients and needs further documentation for other patient groups.

Chimney grafts in aortic occlusive disease.

The aim of this article was to present juxtavisceral aortic occlusive disease with particular reference to a novel therapeutic approach, namely protected stenting by means of so called chimney grafts. The juxta renal aortic occlusion is the last aortoiliac occlusive lesion not to be stented routinely because of the risk for trash and/or need for overstenting of vital aortic side branches. The risk for trash also exists in open repair which makes it particularly challenging in this setting. The patients have advanced atherosclerosis and are poor risks for major surgery. A safe endovascular approach is therefore desirable. These lesions are either predominantly thrombotic or heavily calcified plaques. The thrombotic lesions can be stented under protection of the visceral branches by temporary occlusion balloons. The calcified lesions, on the other hand, require overstenting of the visceral vessels that then need to be preserved by chimney grafts. These endovascular procedures are complex and time consuming but they are associated with less surgical trauma and hence improved morbidity, mortality and recovery. The median term results of chimney grafts are encouraging, although more patients and longer follow-up are still needed.