Endovascular Iliac Branch Devices for Iliac Aneurysms Roy K. Greenberg and Gustavo Oderich Endovascular aneurysm repair (EVAR) offers significant benefits to many patients, yet the applicability of EVAR has been challenged in patients with unfavorable proximal necks or aneurysmal involvement of the iliac arteries. The latter situation occurs in 12% to 40% of patients. Standard therapy involves embolization or coverage of the internal iliac artery, which often results in buttock and thigh claudication and on rare occasion spinal cord ischemia, mesenteric ischemia, and pelvic necrosis. The need and desire to incorporate iliac branches into an aortic repair has led to development of extra-anatomic reconstructions, chimney-type stent grafts, modifications of commercially available stent grafts, and the use of specifically designed iliac branch devices (IBDs). Rationale Complications of not preserving internal iliac artery blood flow during EVAR, such as claudication or sexual dysfunction, are not well studied or reported in most series. Nevertheless, these problems affect up to 50% of patients treated with unilateral internal iliac artery occlusion and up to 80% of those having occlusion of both iliac arteries. The risk of serious complications is greater in patients with thoracoabdominal aneurysms, where compromise of the internal iliac artery circulation has been shown to increase the risk of paraplegia in experimental models and clinical reports. Thus the ability to maintain antegrade perfusion of the pelvic circulation using IBD is potentially useful in patients with limited disease, but it is critical in patients with more extensive disease. Device Design There are currently three device configurations, all based on the Zenith AAA platform (Cook Inc., Bloomington, IN). The two initial designs are essentially modifications of an iliac limb, whereby a branch is sewn to the mid portion of the limb, leaving a proximal stent to mate with a conventional AAA device, and the distal segment to seal and fixate within the external iliac artery. The branch can be short and at a slight angle from the limb direction (straight or S-IBD), or it can be longer and wrapped around the circumference of the iliac limb (helical or H-IBD). The third device is a bifurcated device with a long ipsilateral limb containing the iliac branch (bifurcated or B-IBD). The H-IBD and B-IBD are standard devices, with right- and left-sided designs. The S-IBD has some additional customized options with respect to device length and distal diameters. Device Deployment All of the devices are loaded into a 20-Fr delivery system that contains a preloaded wire that resides just proximal to the proximal aspect of the device for the S-IBD and H-IBD. The B-IBD allows the preloaded wire to exit the limb using a fenestration that is created opposite the branch ostium. When the wires and catheters are removed, this fenestration seals automatically by a flap of fabric that is attached to a stent above the fenestration that falls over the opening (self-sealing fenestration). By snaring this wire from an alternative site (typically the contralateral femoral artery), access is established through the branch. When a sheath (10 Fr) is advanced over the preloaded wire, and the hub of the sheath is punctured with a second access, any advanced wires and catheters will find themselves within the common iliac artery (CIA) aneurysm. Selective cannulation of the internal iliac artery is then accomplished, and a stiff wire is placed into the posterior trunk of this vessel. When the H-IBD or B-IBD are used, a self-expanding stent graft (most commonly a Fluency Graft, Bard, Inc., Tempe, AZ) is advanced to the desired sealing zone within the internal iliac artery or one of its trunks. When the S-IBD is used, a balloon expandable stent graft is used, which may or may not require sheath access into the internal iliac artery. The H-IBD or S-IBD device is then connected to the AAA repair using a limb extension. When the B-IBD is used, the device is mated with the more proximal repair by a long overlap segment within the infrarenal aorta (76–1105 mm). The B-IBD is intended for use with all proximal fenestrated and branched devices, and infrarenal repairs can be completed with any of the devices. Bilateral iliac branch repairs are currently conducted with a H-IBD or S-IBD on one side and the B-IBD on the other side. The B-IBD is a later configuration and carries certain advantages over the earlier designs. Primarily the modular connection to the AAA repair is moved proximally, allowing extensive overlap between the IBD device and aortic repair device, eliminating the two joints that are created when the H-IBD or S-IBD are mated to the AAA repair. Additionally, the length of required common iliac artery to safely perform the procedure is reduced. With both the H-IBD and S-IBD, a reasonably long common iliac artery is required (>5 cm) to prevent the IBD device from extending into the aortic aneurysm proper. The B-IBD device can be used in the setting of shorter (>2.5 cm) common iliac artery, allowing treatment of significantly more patients, particularly female and Asian patients. Results More than 1000 IBDs have been implanted worldwide, yet such numbers are not represented in the published literature. The first reported series by Greenberg and associates in 2006 included 21 patients with three technical failures (14%), all related to the inability to visualize the origin of the internal iliac artery as a result of significant stenosis. Ziegler and associates analyzed 46 patients treated with S-IBDs; the first 26 patients were treated using an early-generation unibody configuration, and the last 20 used the S-IBD system. Technical success improved from 58% with the early-generation device to 85% with the current S-IBD. There were no perioperative deaths, and of the 35 IBDs successfully implanted, none developed endoleak, component separations, or migration. There were four branch occlusions after a mean follow-up of 26 months. Haulon and colleagues reported on 52 patients treated in Lille, France, or at the Cleveland Clinic. Technical success occurred 94% of the time, and during the mean follow-up of 14 months there were no conversions, ruptures, or aneurysm-related deaths. Verzini and associates from Perugia, Italy, reported the only comparative analysis of IBDs versus hypogastric exclusion in 74 patients. In that study, there were no differences in procedure time, contrast use, and technical success, and there were no early deaths. However, there was a trend toward more endoleaks (19% vs. 4%) and pelvic ischemic symptoms (22% vs. 4%) among patients treated with coil embolization when compared with patients treated with iliac branch devices. Karthikesalingam and associates published a conglomerate analysis of nine studies involving 196 patients treated with IBDs. Technical success ranged from 85% to 100%. There were no aneurysm-related deaths. Only one patient with patent IBD complained of buttock claudication. However, late thrombosis of the IBD occurred in 24 patients (12%) and resulted in buttock claudication in 12 (50%) of these patients, implying the importance of antegrade internal iliac artery flow. Endoleak rates were exceedingly low, with only one type I (0.5%) and two type III endoleaks (1%). Type II endoleaks were treated conservatively and were not associated with sac expansion. Reinterventions were required in 12 patients (6%), including five with occlusion stent graft limbs to the external iliac artery. The anatomic suitability for IBD was not detailed in most studies, but in one study (Tielliu and colleagues) the applicability of the repair was criticized for being acceptable in only 52% of their potential IBD candidates. The same group compared open repair of CIA aneurysms to EVAR with an IBD and found that endovascular procedures had fewer complications and similar patency to open repair. An update from Cao’s group reported 100 patients treated with 95% technical success and 81% patency at 5 years. Growth was noted in only 4% of the patients, and there were three device-related endoleaks (one type III and two distal type I) that required treatment. The latest report from the Cleveland Clinic included 138 devices in 130 patients. Technical success was 95% and patency at 5 years was 82%. There were no patients with aneurysmal growth following IBD placement in this series. In this paper, anatomic challenges were stratified such that separate analyses were conducted for a small common iliac artery, the presence of an internal iliac artery aneurysm mandating seal within one of the later artery’s trunks, and tight ostial stenosis of the internal iliac artery. None of these factors had any affect on patency or endoleaks, and only endoleak was associated with a lower technical success rate than experienced in patients without concomitant internal iliac artery occlusive disease. Only gold members can continue reading. 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Endovascular Iliac Branch Devices for Iliac Aneurysms Roy K. Greenberg and Gustavo Oderich Endovascular aneurysm repair (EVAR) offers significant benefits to many patients, yet the applicability of EVAR has been challenged in patients with unfavorable proximal necks or aneurysmal involvement of the iliac arteries. The latter situation occurs in 12% to 40% of patients. Standard therapy involves embolization or coverage of the internal iliac artery, which often results in buttock and thigh claudication and on rare occasion spinal cord ischemia, mesenteric ischemia, and pelvic necrosis. The need and desire to incorporate iliac branches into an aortic repair has led to development of extra-anatomic reconstructions, chimney-type stent grafts, modifications of commercially available stent grafts, and the use of specifically designed iliac branch devices (IBDs). Rationale Complications of not preserving internal iliac artery blood flow during EVAR, such as claudication or sexual dysfunction, are not well studied or reported in most series. Nevertheless, these problems affect up to 50% of patients treated with unilateral internal iliac artery occlusion and up to 80% of those having occlusion of both iliac arteries. The risk of serious complications is greater in patients with thoracoabdominal aneurysms, where compromise of the internal iliac artery circulation has been shown to increase the risk of paraplegia in experimental models and clinical reports. Thus the ability to maintain antegrade perfusion of the pelvic circulation using IBD is potentially useful in patients with limited disease, but it is critical in patients with more extensive disease. Device Design There are currently three device configurations, all based on the Zenith AAA platform (Cook Inc., Bloomington, IN). The two initial designs are essentially modifications of an iliac limb, whereby a branch is sewn to the mid portion of the limb, leaving a proximal stent to mate with a conventional AAA device, and the distal segment to seal and fixate within the external iliac artery. The branch can be short and at a slight angle from the limb direction (straight or S-IBD), or it can be longer and wrapped around the circumference of the iliac limb (helical or H-IBD). The third device is a bifurcated device with a long ipsilateral limb containing the iliac branch (bifurcated or B-IBD). The H-IBD and B-IBD are standard devices, with right- and left-sided designs. The S-IBD has some additional customized options with respect to device length and distal diameters. Device Deployment All of the devices are loaded into a 20-Fr delivery system that contains a preloaded wire that resides just proximal to the proximal aspect of the device for the S-IBD and H-IBD. The B-IBD allows the preloaded wire to exit the limb using a fenestration that is created opposite the branch ostium. When the wires and catheters are removed, this fenestration seals automatically by a flap of fabric that is attached to a stent above the fenestration that falls over the opening (self-sealing fenestration). By snaring this wire from an alternative site (typically the contralateral femoral artery), access is established through the branch. When a sheath (10 Fr) is advanced over the preloaded wire, and the hub of the sheath is punctured with a second access, any advanced wires and catheters will find themselves within the common iliac artery (CIA) aneurysm. Selective cannulation of the internal iliac artery is then accomplished, and a stiff wire is placed into the posterior trunk of this vessel. When the H-IBD or B-IBD are used, a self-expanding stent graft (most commonly a Fluency Graft, Bard, Inc., Tempe, AZ) is advanced to the desired sealing zone within the internal iliac artery or one of its trunks. When the S-IBD is used, a balloon expandable stent graft is used, which may or may not require sheath access into the internal iliac artery. The H-IBD or S-IBD device is then connected to the AAA repair using a limb extension. When the B-IBD is used, the device is mated with the more proximal repair by a long overlap segment within the infrarenal aorta (76–1105 mm). The B-IBD is intended for use with all proximal fenestrated and branched devices, and infrarenal repairs can be completed with any of the devices. Bilateral iliac branch repairs are currently conducted with a H-IBD or S-IBD on one side and the B-IBD on the other side. The B-IBD is a later configuration and carries certain advantages over the earlier designs. Primarily the modular connection to the AAA repair is moved proximally, allowing extensive overlap between the IBD device and aortic repair device, eliminating the two joints that are created when the H-IBD or S-IBD are mated to the AAA repair. Additionally, the length of required common iliac artery to safely perform the procedure is reduced. With both the H-IBD and S-IBD, a reasonably long common iliac artery is required (>5 cm) to prevent the IBD device from extending into the aortic aneurysm proper. The B-IBD device can be used in the setting of shorter (>2.5 cm) common iliac artery, allowing treatment of significantly more patients, particularly female and Asian patients. Results More than 1000 IBDs have been implanted worldwide, yet such numbers are not represented in the published literature. The first reported series by Greenberg and associates in 2006 included 21 patients with three technical failures (14%), all related to the inability to visualize the origin of the internal iliac artery as a result of significant stenosis. Ziegler and associates analyzed 46 patients treated with S-IBDs; the first 26 patients were treated using an early-generation unibody configuration, and the last 20 used the S-IBD system. Technical success improved from 58% with the early-generation device to 85% with the current S-IBD. There were no perioperative deaths, and of the 35 IBDs successfully implanted, none developed endoleak, component separations, or migration. There were four branch occlusions after a mean follow-up of 26 months. Haulon and colleagues reported on 52 patients treated in Lille, France, or at the Cleveland Clinic. Technical success occurred 94% of the time, and during the mean follow-up of 14 months there were no conversions, ruptures, or aneurysm-related deaths. Verzini and associates from Perugia, Italy, reported the only comparative analysis of IBDs versus hypogastric exclusion in 74 patients. In that study, there were no differences in procedure time, contrast use, and technical success, and there were no early deaths. However, there was a trend toward more endoleaks (19% vs. 4%) and pelvic ischemic symptoms (22% vs. 4%) among patients treated with coil embolization when compared with patients treated with iliac branch devices. Karthikesalingam and associates published a conglomerate analysis of nine studies involving 196 patients treated with IBDs. Technical success ranged from 85% to 100%. There were no aneurysm-related deaths. Only one patient with patent IBD complained of buttock claudication. However, late thrombosis of the IBD occurred in 24 patients (12%) and resulted in buttock claudication in 12 (50%) of these patients, implying the importance of antegrade internal iliac artery flow. Endoleak rates were exceedingly low, with only one type I (0.5%) and two type III endoleaks (1%). Type II endoleaks were treated conservatively and were not associated with sac expansion. Reinterventions were required in 12 patients (6%), including five with occlusion stent graft limbs to the external iliac artery. The anatomic suitability for IBD was not detailed in most studies, but in one study (Tielliu and colleagues) the applicability of the repair was criticized for being acceptable in only 52% of their potential IBD candidates. The same group compared open repair of CIA aneurysms to EVAR with an IBD and found that endovascular procedures had fewer complications and similar patency to open repair. An update from Cao’s group reported 100 patients treated with 95% technical success and 81% patency at 5 years. Growth was noted in only 4% of the patients, and there were three device-related endoleaks (one type III and two distal type I) that required treatment. The latest report from the Cleveland Clinic included 138 devices in 130 patients. Technical success was 95% and patency at 5 years was 82%. There were no patients with aneurysmal growth following IBD placement in this series. In this paper, anatomic challenges were stratified such that separate analyses were conducted for a small common iliac artery, the presence of an internal iliac artery aneurysm mandating seal within one of the later artery’s trunks, and tight ostial stenosis of the internal iliac artery. None of these factors had any affect on patency or endoleaks, and only endoleak was associated with a lower technical success rate than experienced in patients without concomitant internal iliac artery occlusive disease. Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Technical Aspects of Percutaneous Carotid Angioplasty and Stenting for Arteriosclerotic Disease Management of Acute Limb Ischemia Complicating Aortic Reconstruction Treatment of Dyslipidemia and Hypertriglyceridemia Intraoperative Assessment of the Technical Adequacy of Carotid Endarterectomy Stay updated, free articles. Join our Telegram channel Join
