The so-called chimney technique for endovascular treatment of aortic aneurysms involving reno-visceral vessels was first described in 2003 as a "bailout" procedure and further developed in 2007 as an alternative endovascular therapy method [1, 2]. The first series with more than five abdominal cases were reported by Ohrlander et al. in 2008, by Hiramoto et al. in 2009, and by Donas et al. in 2009 [3, 4, 5]. The publications demonstrate the feasibility of the procedure with good results regarding 30-day morbidity and mortality.
In 2013, two centers reported on the results of a CT angiography follow-up after 24 months in 124 high-risk patients, in whom pararenal aneurysms had been successfully excluded using the chimney technique in 90% of cases [6]. Another two-center study demonstrated that the combination of two different materials (Excluder (Gore) stent graft with Viabahn (Gore) and the Endurant prosthesis (Medtronic) with Advanta V12 (Getinge)) also has a good patency rate of 95% and a low incidence of type Ia endoleaks (2%) [7]. A 2012 in-vitro study came to the same conclusion [8].
Numerous publications on this topic emerged from the PERICLES Registry("Collected World Experience About the Performance of the Snorkel/Chimney Endovascular Technique in the Treatment of Complex Aortic Pathologies"). Thus, in 2015, the world's largest experience with this technique was published based on 517 cases. The patency rate of the chimney grafts was 94.1%, and the regression of the diameter of the treated aneurysms averaged 6.5 cm. To minimize the risk of endoleak, the group recommended creating a new landing zone of 20 mm [9]. Meanwhile, numerous further publications have emerged from the registry [10-19].
The occurrence of type Ia endoleak has been viewed by some authors as the "Achilles' heel" of chimney treatment [20]. A distinction is made between "high flow" (HF) and "low flow" (LF) endoleaks. In HF, the contrast medium exits outside the aortic graft immediately after application, while in LF, it appears significantly delayed in the late phase after contrast medium application. Studies show that LF endoleaks are no longer present after a short time and thus have no clinical relevance [21 - 24]. A study from Zurich (conservative with close-meshed CT monitoring) comes to a similar conclusion [25]. In contrast, HF endoleaks represent an absolute indication for intervention.