Citation for published version (APA): Tielliu, I. F. J. (2010). Endovascular repair of peripheral artery aneurysms Groningen: s.n.

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1 University of Groningen Endovascular repair of peripheral artery aneurysms Tielliu, Ignace François Jacques IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2010 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Tielliu, I. F. J. (2010). Endovascular repair of peripheral artery aneurysms Groningen: s.n. Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date:

2 INTRODUCTION Chapter 2 Design and rationale of the thesis 29

3 Chapter 2 In this thesis, peripheral artery aneurysms are defined as solitary aneurysms that are located below the aortic bifurcation as compared to more centrally located aortic or aortoiliac aneurysms. Thus, the thesis focuses on aneu rysms of the iliac and popliteal artery, as they are by far more prevalent compared to aneurysms of the femoral arteries. The indication for treatment of iliac aneurysms is mainly based on the chance of sudden rupture, which is associated with morbidity and mortality. Popliteal aneurysms, on the contrary, rarely do rupture but tend to thrombose instead or turn out to be sources of acute or chronic peripheral embolization, both often leading to acute limb ischemia. Traditionally, iliac and popliteal artery aneurysms have been treated by open repair. Starting at the beginning of the 1990 s, the ongoing evolution in endovascular technology made it possible to treat peripheral aneurysms with a stent-graft. These stent-grafts incorporate a sealing fabric as well as a skeleton made of a metal or alloy stent material. The skeleton provides the radial force needed for apposition of the stent-graft to the wall of the artery and for fixation, but it also bears the potential to kink when a stent-graft is positioned in tortuous vessels, and to fracture when positioned at a hinge point of the artery. This thesis is divided in two sections. In the first section, the endovascular treatment of iliac artery aneurysms is analyzed. The second section will focus on the endovascular treatment of popliteal artery aneurysms in particular. Section I The endovascular treatment of iliac artery aneurysms A challenging issue for endovascular iliac aneurysm repair includes dealing with the often tortuous character of the iliac vessels. Iliac arteries not only follow the natural curve of the pelvis, but also tend to elongate when becoming aneurysmatic. Another issue of importance is the mismatch in diameter between the common and external iliac artery that often precludes the use of a cylindrical stent-graft. The design of the stent-graft is therefore important to adequately manage tortuosity and diameter mismatch. The results of a cohort study of solitary iliac artery aneurysms which were treated with a funnel-shaped stent-graft made of a nitinol stent and an inner lining of expanded polytetrafluoroethylene (PTFE), as well as an overview of the literature on iliac stent-grafting, are presented in Chapter 3. 30

4 Design and Rationale Another item specifically associated with iliac aneurysm repair is the fate of the internal iliac artery. Common iliac artery aneurysms oftentimes extend up to or include the origin of the internal iliac artery. In those cases, the internal iliac artery must be overstented in order to assure adequate sealing in the external iliac artery. In cases where the aneurysm incorporates the origin of the internal iliac artery, this vessel is additionally and intentionally occluded with coils or with a plug to prevent a so-called endoleak resulting from back bleeding from the internal iliac artery into the aneurysm sac. To try to overcome the negative effects of internal iliac occlusion several techniques, most of them combining open and endovascular surgery, have been developed to preserve internal iliac perfusion. In contrast with the open surgical techniques to spare the internal iliac artery, the iliac branched device assures internal iliac artery perfusion and is introduced by endovascular means only. The pioneering results of a cohort study of endovascular iliac aneurysm repair with the iliac branched device are reported in Chapter 4. The iliac branched device incorporates a preloaded indwelling guide wire that passes through the internal iliac branch. This indwelling wire can be snared from the contralateral femoral access side. This through-and-through crossover wire enables the advancement of a stent-graft from the contralateral side to bridge the gap between the iliac branch and the internal iliac artery. For the introduction of this bridging stent-graft a stable position of the crossover sheath is mandatory. Therefore, it has been advized to keep the through-and-through indwelling wire in position until the bridging stent-graft is in place. This requires working with parallel wires through one sheath, and can cause problems as a result of friction and entangling. Ongoing experience allowed us to develop an alternative easier and safer technique for introduction and deployment of the iliac branched device. This modified technique using tromboned sheaths is described in detail in Chapter 5. Section II The endovascular treatment of popliteal artery aneurysms The most important challenge in endovascular popliteal aneurysm repair is how to cope with effects of repetitive bending at the level of the hinge point of the popliteal artery. In addition, as in iliac aneurysm repair, the diameter 31

5 Chapter 2 mismatch between the proximal and distal landing zone is a matter of concern. Again, design of the stent-graft and ability to handle these aspects are important issues. For popliteal aneurysm repair we deliberately chose a flexible stent-graft with a nitinol skeleton and expanded polytetrafluoroethylene (PTFE) fabric lining at the luminal side. The pioneering results of a cohort study of popliteal artery aneurysms treated with this type of stent-graft are presented in Chapter 6. A stent-graft crossing a flexible joint such as the knee that is subject to repetitive flexion-extension movements is prone to complications. In addition, it is often necessary to use multiple stent-grafts to cover the lesion including proximal and distal landing zones. The flexibility of the knee joint and the need for multiple overlapping stent-grafts are both the basis of technical problems or complications. The effect of the learning curve on outcome of popliteal stent-grafting and including the occurrence of occlusions, migrations, stent fractures, and stenoses, was the subject of the study that is outlined in Chapter 7. As mentioned before, the hinge point of the popliteal artery in a highly flexible knee joint is the basis of reluctancy among many vascular surgeons and interventional radiologists to use stent-grafts in this area. An increasing cumulative number of stent fractures was observed in the cohort of popliteal artery aneurysms after endovascular repair over the years. This warranted a new study on basically the same cohort of popliteal aneurysms as described in chapter 7 and focussing specifically on the occurrence of stent fractures. This study is outlined in Chapter 8. In Chapter 9, the results of the different studies are summarized and some perspectives towards future development are discussed. 32