The sandwich technique to treat complex aortoiliac or isolated iliac aneurysms: Results of midterm follow-up

Transcription

1 The sandwich technique to treat complex aortoiliac or isolated iliac aneurysms: Results of midterm follow-up Armando C. Lobato, MD, PhD, and Luciana Camacho-Lobato, MD, PhD, São Paulo, Brazil Objective: To ascertain midterm outcomes of the sandwich technique (ST) for internal iliac artery endorevascularization (ER). Methods: All consecutive patients with complex aortoiliac aneurysms, isolated common iliac artery aneurysms, and abdominal aortic aneurysms with bilateral short, nondiseased common iliac artery undergoing elective endovascular aneurysm repair (EVAR) with the ST at our center, between October 2008 and March 2011, were invited to participate in the present study. Patients were considered eligible for this procedure only when their aneurysm features did not fulfill the requirements for standard EVAR. Follow-up assessments were carried out at 1 month and every 6 months thereafter and included computed tomographic angiography or duplex ultrasound. The study was approved by the Institutional Review Board, and all patients gave written informed consent. Results: A cohort of 40 patients (95% male; mean age, 72.2 years) was followed over a mean follow-up period of 12 ± 4.4 months (range: 6-30 months); 48 internal iliac artery (IIA) ER with ST were undertaken. Internal iliac artery aneurysm (IIAA) ER technical success rate was 100%. Primary patency rate was 93.8% on account of three IIA ER occlusions, occurring early in the study. Early and late related mortality rate was 0% and late unrelated mortality rate was 2.5%. Iliac aneurysm sac evolution demonstrated a significant (at least 5 mm) decrease in diameter in 16 (34.8%) common iliac artery aneurysms, no change in 29 (63%) common iliac artery aneurysms, and an increase in one patient (2.2%). Statistical significance was reached only for comparisons between baseline and 30 months (P [.039). Late buttock claudication rate was 0% after IIA ER with ST and 14.3% after IIA coil embolization. Conclusions: The ST expands the limits of EVAR for complex aortoiliac aneurysms or IIAA in a safe, easy to perform, and cost-effective manner. (J Vasc Surg 2013;57:26S-34S.) Endovascular aneurysm repair (EVAR) is currently accepted as the first-line treatment for abdominal aortic aneurysms (AAA) due to decreased operative mortality and morbidity rates and shorter patient recovery times. 1-3 Exclusion criteria for this procedure are mainly of the anatomic type and include unfit proximal aortic necks and/or iliac arteries. AAA combined with common iliac artery (CIA) aneurysms is found in 20% to 30% of AAA patients 4 and requires a more demanding procedure due to potential difficulties in obtaining adequate distal landing zones for stent-graft limb fixation. Another difficult scenario, particularly prevalent in Asians, consists of abdominal aortic aneurysms with bilateral short, nondiseased common iliac artery (AAA w/scia), 5 as secure distal fixation of a bifurcated stent graft requires a long and healthy segment of CIA. 6 Extending the iliac limbs of the stent graft past the internal iliac artery (IIA) origin, to provide a secure seal, can be accomplished, however, From the São Paulo Vascular and Endovascular Surgery Institute (ICVE-SP). Author conflict of interest: none. Reprint requests: Armando C. Lobato, MD, PhD, São Paulo Vascular and Endovascular Surgery Institute (ICVE-SP), R. Maestro Cardim 560/ cjtos , São Paulo, Brazil ( aclobato@icve.com.br). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest /$36.00 Copyright Ó 2013 by the Society for Vascular Surgery. bilateral IIA occlusion can be problematic in 12% to 45% of cases. 7-9 Buttock claudication, ischemic colitis, neurologic deficits, bowel or bladder dysfunction, and erectile dysfunction are complications that might be elicited by IIA interruption. Occlusion of one IIA is generally well tolerated. 10 Bilateral IIA occlusion, however, is accompanied by a higher incidence of buttock claudication as well as other manifestations of pelvic ischemia. A recent review of 634 patients undergoing unilateral or bilateral IIA occlusion reported buttock claudication and erectile dysfunction in 28% and 17% of the patients, respectively. Hence, preservation of flow to at least one IIA is recommended, if at all possible A few open and/or endovascular techniques have been developed over the past decade to increase the success rate of endovascular repair in AAA with combined CIA aneurysms (CIAA) extending to the iliac bifurcation The bell-bottom technique 19,20 as well as the trifurcated endograft technique can address common iliac arteries with diameters between 18 to 24 mm. The need for two main body stent grafts in the latter, though, makes this technique rather expensive. 21 Branched iliac device (IBD; Zenith Zebis, Cook Inc, Bloomington, Ind) present another alternative to avoid IIA occlusion Placement of the side branch of the endograft in the IIA, however, is technically difficult and cannot be performed in the setting of tortuous anatomy, as well as in thin (CIA lumen is #18 mm in diameter) or short CIAs (<40 mm in length). In addition, branched devices are not widely 26S

2 Volume 57, Number 2S Lobato and Camacho-Lobato 27S Table I. Anatomic features as assessed by CTA AIA ICIAA AAA þ SCIA (bilateral) Patients, No. (%) 33 (82.5) 6 (15) 1 (2.5) Diameter (mean 6 SD) mm mm 57 mm CIA/CIAA <40 mm in length, No. (mean 6 SD) 4 ( mm) 0 2 ( mm) Bilateral CIAA, No. (%) 27 (81.8) 3 (50) 0 Unilateral CIAA, No. (%) 6 (18.2) 3 (50) 0 AAA without CIAA associated, No. (%) (100) CIA/CIAA lumen <18 mm, No. (mean 6 SD) 10 ( mm) 2 ( mm) 2 ( mm) Patients with concomitant IIAA, No. (mean diameter 6 SD) Bilateral 4 ( mm) 1 (29 mm) 0 Unilateral 7 ( mm) 1 (33 mm) 0 AAA, Abdominal aortic aneurysm; AIA, aortoiliac aneurysm; AAA þ SCIA (bilateral), abdominal aortic aneurysm with bilateral short healthy common iliac artery; CIA, common iliac artery; CIAA, common iliac artery aneurysm; CTA, computed tomographic angiography; ICIAA, isolated common iliac artery aneurysm; IIA, internal iliac artery; SD, standard deviation. available. 27 Relocation of the iliac artery bifurcation by IIA implantation onto the distal external iliac artery is another alternative to preserve pelvic flow in selected candidates for EVAR. 13 The ST, developed in 2008, is a new technique to safely address AAA encumbered by adverse iliac anatomy, including aortoiliac aneurysms (AIA) and isolated CIAA (ICIAA) extending to the IIA, or AAA w/scia. 28 We currently report the results of a midterm follow-up of complex AIA or ICIAA treated with the ST. METHODS Study design. This prospective study comprises 40 consecutive patients undergoing elective EVAR with the ST to treat AIA, ICIAA, or AAA w/scia at our center, between October 2008 and March Patients were considered eligible for this procedure only when their aneurysm features (Table I) did not fulfill the requirements for standard EVAR technique. Inclusion criteria were mainly of the anatomic type and included (1) AIA with no bilateral distal landing zone; (2) AIA with no unilateral distal landing zone plus contralateral IIA aneurysm (IIAA) or contralateral IIA with previous occlusion/ severe stenosis; (3) AAA with bilateral short healthy CIA; (4) bilateral ICIAA with no bilateral distal landing zone; and (5) unilateral ICIAA with no unilateral distal landing zone plus contralateral IIAA or contralateral IIA with previous occlusion/severe stenosis. After the first 18 months of the study, the IBD was made available to our center, causing us to narrow the previously mentioned inclusion criteria as to include only patients that could not have their aneurysms safely addressed by IBD. They are (1) CIA <40 mm in length; (2) CIAA lumen #8 mm in diameter; (3) very tortuous CIA anatomy; (4) a distal landing zone <10 mm in length on the main internal iliac trunk; (5) ICIAA with proximal landing zone (CIA) >12 mm in diameter and aortic bifurcation <18 mm in diameter; (6) external iliac artery occlusion; (7) large IIAA; (8) CIA dissection complicated with CIAA and true lumen #18 mm in diameter; and (9) previous AAA open repair with Dacron graft complicated with CIA anastomotic false aneurysm. The present study was approved by the Hospital Institutional Review Board and all patients gave written informed consent. The technique. A detailed description of this technique has been reported elsewhere. 28 Briefly, the ST for AIA extending to bilateral internal iliac artery (IIA) comprises four easy-to-perform steps. (1) The main body of a bifurcated aortic stent graft is inserted using an ipsilateral femoral approach and deployed with the distal end of the iliac limb placed 1 cm above the iliac bifurcation (Fig 1, B). (2) The ipsilateral IIA is cannulated using a left brachial approach and a self-expandable covered stent (SECS) is placed at least 1 cm inside the nondiseased IIA, with at least 5 cm overlapping into the iliac limb extension (Fig 1, C-E). (3) The iliac limb extension is positioned 1 cm below the SECS proximal end, deployed and accommodated with a latex balloon prior to deploying the SECS (Fig 1, F). (4) The contralateral common and internal iliac arteries can be treated in the same fashion (Fig 1, G-I). Follow-up assessment included routine office visits and imaging (computed tomographic angiography or duplex ultrasound for patients with nondialysis-dependent chronic renal insufficiency) performed at 1, 6, and 12 months and every 6 months thereafter. Statistical analysis. Primary end points included technical success rate, IIA ER patency rate, fate of the aneurysm sac, and procedure-related or unrelated early (less than 30 days) and late mortality rates (more than 30 days). Additional variables included complication rates (pelvic ischemia, endoleak, access complications, end-organ complications, and aneurysm rupture) and performance data (procedure and fluoroscopy times, contrast and blood transfusion volume, hospital length of stay, and conversion rate to open aneurysm repair and secondary procedures). Statistical analysis included descriptive statistics as well as the Friedman test for sac evolution assessment along time (Prism 5; Graphpad Software Inc, San Diego, Calif). RESULTS The population. Forty patients (95% male) with a mean age of 72.2 years underwent EVAR with the ST during the study period. Twenty-three patients were enrolled in the

3 28S Lobato and Camacho-Lobato February Supplement 2013 Fig 1. A, Aortoiliac aneurysm extending to the internal iliac artery (IIA). B, Deploy the main body of the bifurcated stent graft, (C) followed by cannulation of the ipsilateral IIA using a left brachial access. D, Place a self-expandable covered stent (SECS) at least 1 cm inside the nondiseased IIA with 5 cm overlapping into the iliac limb extension (E) followed by positioning of an iliac limb extension 1 cm below the SECS s proximal end. F, First deploy the iliac limb extension and then the SECS. For bilateral sandwich repair (G) deploy the contralateral iliac limb stent graft, by cannulation of the remaining IIA using a left brachial access. H, Deploy first the iliac limb extension and then the SECS. I, Postoperative three-dimensional computed tomographic angiography (CTA) of a bilateral IIA endorevascularization with the sandwich technique. first 18 months of the study, and 17 were included in the second half of the study, after inclusion criteria revision. Patient demographic features and comorbid conditions are summarized in Table II. The mean follow-up period was months (range, 6-30 months). Two patients (5%) were lost to follow-up after 12 and 16 months. AIA extended to both CIA bifurcations in 27 patients (67.5%) and to only one in six patients (15%). This group of patients underwent 26 unilateral and seven bilateral ST procedures. Three patients (7.5%) had bilateral ICIAA extending to both iliac artery bifurcations and another three patients (7.5%) had unilateral ICIAA extending to only one iliac artery bifurcation. Six unilateral ST procedures were performed in these patients. The remaining patient had AAA with bilateral short nondiseased CIA (<25 mm in length and 11 mm in diameter) (2.5%) that was submitted to a bilateral ST procedure (Table I). Overall, 48 IIA ER with the ST were undertaken in the 40 study patients. The devices. The type and amount of endografts and SECS used to treat each of the three types of aneurysm described are summarized in Table III. Thirty-three commercially available aortic bifurcated stent grafts, 40 SECS, and 40 iliac stent graft extensions were used to treat the 33 AIA. Five commercially available aortic stent grafts, 10 SECS, and six iliac stent graft extensions were used to treat the six ICIAA. The remaining patient with AAA and Table II. Patient demographics and comorbidities Features No. (%) Sex Male 38 (95) Female 2 (5) Mean age, years Race Caucasian 35 (87.5) Asian 3 (7.5) Black 2 (5) Hypertension 26 (65) Smoking 24 (60) COPD 22 (55) Coronary artery disease 15 (37.5) PAOD 15 (37.5) Hypercholesterolemia 11 (27.5) Diabetes 6 (15) Chronic renal insufficiency (nondialytic) 6 (15) Obesity 6 (15) TIA/stroke 3 (7.5) Medications in use b blockers 18 (45) Statins 17 (42.5) Antiplatelet 16 (40) COPD, Chronic obstructive pulmonary disease; PAOD, peripheral artery occlusive disease; TIA, transient ischemic attack. bilateral short nondiseased CIA was treated with one bifurcated stent graft, two iliac stent-graft extensions, and two SECS (Table III).

4 Volume 57, Number 2S Lobato and Camacho-Lobato 29S Table III. Type and amount of endografts used to treat the aortoiliac aneurysms Type of aortic bifurcated stent graft/ self-expandable covered stent No. (%) Iliac stent graft extension, No. (%) Viabahn a sizes (No.) Aortoiliac aneurysms Excluder 20 (61) 23 (57.5) mm (7) mm (6) mm (4) mm (4) mm (2) mm (1) Talent/Endurant 9 (27) 10 (25) mm (3) mm (3) mm (2) mm (2) mm (1) Abdominal E-Vita 1 (3) 2 (5) mm (1) mm (1) Braile b 1 (3) 2 (5) mm (1) Powerlink 1 (3) 2 (5) mm (1) Zenith 1 (3) 1 (2.5) mm (1) Isolated common iliac aneurysms Excluder 3 (50) 2 (33.3) mm (2) mm (1) Talent/Endurant 1 (25) 2 (33.3) mm (1) Braile b 1 (25) 2 (33.3) mm (2) mm (1) Viabahn mm (1) mm (1) AAA with short CIA Excluder 1 (100) 2 (100) mm (2) Total 40 (100) 48 (100) 51 (100%) AAA, Abdominal aortic aneurysm; CIA, common iliac artery; IIA, internal iliac artery. a Used for IIA endorevascularization. b Brazilian stent graft. ST procedure data. Ninety percent of patients underwent ST under general anesthesia, and 100% of them had open bilateral femoral access. An additional percutaneous left brachial access was necessary in the majority of patients (37/92.5%) for the sake of SECS insertion. An open axillary access was required in the remaining three patients as a result of the large profile (12F) of the SECS selected. A mean operating time of minutes, a mean fluoroscopy time of minutes, a mean contrast volume of ml, and a mean hospital length of stay of days were necessary to perform the sandwich procedure. Blood transfusion was necessary in only four patients (Table IV). Ancillary procedures. Seven bell-bottom procedures (CIAA <20 mm in diameter), 11 long contralateral iliac stent graft limbs landing in the external iliac artery, and 14 IIA coil embolizations were performed in addition to the 48 IIA ER to treat the 69 CIAA and the 18 IIAA. Primary end points. IIA ER technical success rate was 100%. Primary patency rate was 93.8% on account of three IIA ER occlusions, occurring early in the study. In two of these cases, the SECS were placed too distally in the gluteal artery (<4 mm in diameter) and in the third patient, the IIA ER occlusion was attributed to distal IIA dissection by an extra-stiff guidewire tip (Table IV). Early and late related mortality rate was 0%, and late unrelated mortality rate was 2.5%. Early and late results are displayed in Tables IV and V, respectively. The evolution of the 46 iliac aneurysm sacs treated with the ST revealed a significant (at least 5 mm) decrease in diameter (Fig 2, A-F) in 16 (34.8%) CIAA, no change in 29 (63%) CIAA, and an increase (2.2%) in one. This case was addressed conservatively on patient demand and maintained stable in posterior assessments. Statistical significance was reached only for comparisons between baseline (0 months) and 30 month timepoints (P ¼.039) (Fig 3). Complications. Overall, early buttock claudication was observed in two (4.2%) patients submitted to IIA ER with the ST presenting unilateral IIA ER occlusion, and in eight (57.1%) patients undergoing IIA coil embolization (Table IV). One patient developed erectile dysfunction, which persisted despite buttock claudication resolution after 6 and 10 months (Table V). There were no cases of ischemic colitis or buttock ischemia. Late buttock claudication rates were 0% in the IIA ER with the ST group opposed to 14.3% in the coil embolization group. One ipsilateral iliac limb stent graft thrombosis occurred 12 hours after the main procedure. Patency was restored with thromboembolectomy followed by placement of a self-expandable stent inside the Excluder iliac limb extension stent graft (W. L. Gore & Associates, Flagstaff, Ariz).

5 30S Lobato and Camacho-Lobato February Supplement 2013 Table IV. Thirty-day results of the ST procedure Patients (n ¼ 40) Amount (mean 6 SD) or No. (%) Procedure time, minutes Fluoroscopy time, minutes Contrast volume, ml Hospital length of stay, days Blood transfusion, ml a 30 Early mortality rate 0 (0) Aneurysm rupture 0 (0) Conversion rate 0 (0) Technical success rate 48 (100) Buttock claudication rate Total 10 (25) After IIA coil embolization (n ¼ 14) 8 (57.1) After IIA ER (n ¼ 48) 2 (4.2) Erectile dysfunction 1 (2.5) IIA/IIAA ER occlusion (rate per vase treated) 3 (4.2) 48 Ipsilateral iliac limb stent graft occlusion (rate per vase treated) 1 (2.5) 40 Contralateral iliac limb stent graft occlusion (rate per vase treated) 1 (2.6) 38 Brachial artery occlusions 2 (5.4) Brachial access (n = 37) Inguinal incision hematoma 1 (1.3) Femoral access (n = 78) Secondary procedures 7 (17.5) Type I endoleak 2 (5) Type II endoleak 4 (10) Type III endoleak (sandwich-technique related) 1 (2.5) Acute myocardial infarction 2 (5) Renal artery occlusion (n ¼ 48) (rate per vase) 1 (1.2) Renal function impairment 5 (12.5) ER, Endorevascularization; IIA, internal iliac artery; IIAA, internal iliac artery aneurysm; SD, standard deviation. a Blood transfusion was necessary for four patients. One contralateral iliac limb stent graft occlusion occurred on the 29th postoperative day. This patient had a previous unilateral CIAA and IIAA open repair 7 years before that left an external iliac artery dissection, probably caused by vascular clamping. We did not fix the dissection when we performed the ST for the AIA associated with IIAA. The patient arrived at the emergency room with acute left limb ischemia, and an urgent secondary procedure was undertaken under local anesthesia. Patency was restored through intraoperative angiography, thromboembolectomy, and profundoplasty followed by self-expandable bare stent deployment to treat the previous left external iliac artery dissection. The intraoperative angiogram revealed patency of the right IIAA ER, and a left renal artery occlusion without renal function impairment during follow-up (Table IV). Four patients with previous nondialysis-dependent chronic renal insufficiency and one with previous normal renal function had further impairment of their renal function during the postoperative period, despite the preoperative renal function protection measures undertaken. Two patients developed acute myocardial infarction on second and third postoperative days. One of them underwent Table V. Late results of the procedure Patients (n ¼ 40) Amount (mean 6 SD) or No. (%) Mean follow-up period, months Range: 6-30 months Type I endoleak 0 (0) Type II endoleak a 1 (2.5) Type III endoleak 0 (0) Related mortality 0 (0) Unrelated mortality 1 (2.5) Aneurysm rupture 0 (0) Conversion to open 0 (0) aneurysm repair IIA/IIAA ER occlusion 0 (0) (rate per vase treated) Ipsilateral iliac limb stent 0 (0) graft occlusion (rate per vase treated) Contralateral iliac limb stent 0 (0) graft occlusion (rate per vase treated) Secondary procedures 0 (0) Buttock claudication rate Total: 2 (5) After IIA coil embolization b 2 (14.3) After IIA ER 0 (0) Erectile dysfunction 1 (2.5) Renal artery occlusion 0 (0) Renal function impairment 0 (0) ER, Endorevascularization; IIA, internal iliac artery; SD, standard deviation. a Three type II endoleaks sealed spontaneously at 6, 12, and 18 months. b Fourteen coil embolizations performed. a successful coronary artery stent, and the other was managed conservatively (Table IV). Two brachial artery early occlusions were successfully treated nonoperatively using anticoagulation and vasodilation. One incisional hematoma was treated by surgical evacuation (Table IV). Two type I, four type II, and one type III endoleaks were detected at completion angiography. The two patients with a type I endoleak were successfully treated with deployment of a proximal aortic cuff during the main procedure. The type III endoleak was of very low volume and, therefore, was managed conservatively with complete resolution at the first month computed tomographic angiography. Three of the type II endoleaks sealed spontaneously by the 18-month follow-up without any secondary procedures. One late type II endoleak was diagnosed at 12 months and was associated with a 5 mm increase of the aortic aneurysm sac. This patient was offered a secondary procedure but refused and is currently being managed conservatively. Early results are displayed in Table IV. No new type I, II, and III endoleaks as well no IIA ER or limb occlusion occurred after 12 months of follow-up. DISCUSSION Appropriate management of CIAA is not standardized. 24 Feasibility of EVAR in the setting of unsuitable CIA has been the focus of research over the course of the last decade Several techniques have been reported

6 Volume 57, Number 2S Lobato and Camacho-Lobato 31S Fig 2. A, Preoperative right common iliac artery aneurysm (CIAA) diameter measured by computed tomographic (CT) scan. B, Preoperative right internal iliac artery aneurysm (IIAA) diameter measured by CT scan. C, Right CIAA diameter measured by CT scan at the 1-month postoperative assessment. D, Right IIAA diameter measured by CT scan at the 1-month postoperative assessment. E, Thirty-month postoperative right CIAA diameter measured by CT scan. Note the CIA aneurysm sac disappeared at the 30-month assessment. F, Thirty-month postoperative right IIAA diameter measured by CT scan. Note the internal iliac artery (IIA) aneurysm sac reduction at the 30-month assessment. to either preserve (trifurcated endograft, relocation/ bypass, external-to-internal endografting) blood flow to the IIAs or occlude these arteries (simple coverage, IIA coil embolization) The bell-bottom technique 19 was developed to approach CIA with diameters between 18 and 24 mm, and good outcomes have been reported in diameters up to 30 mm. Long-term follow-up has demonstrated further vessel dilatation and/or distal endoleak attributable to retrograde migration of the stent graft, necessitating secondary intervention. 29 The branched iliac stent graft technique is an appealing alternative to avoid IIA occlusion, but is more complicated compared with a standard EVAR, 26 requires a very skilled and well-trained endovascular team, is expensive, is not widely available for commercial use, and has various anatomic restrictions. 23,24 The current study followed 40 patients treated with the ST for months. Forty-eight IIA ER were performed over 69 CIAA (seven bilateral) and one AAA with bilateral short healthy CIA. Twenty-three remaining CIAA were managed by concomitant IIA coil embolization followed by long contralateral iliac limb stent graft deployment landing at the external iliac artery, bellbottom technique, or simple coverage of IIA origin by long contralateral iliac limb stent graft deployment. The mean operating time ( minutes), mean fluoroscopy time ( minutes), mean contrast volume ( ml), and mean hospital length of stay ( days) necessary to perform the sandwich procedure were similar to the ones reported for the branched iliac stent graft technique Very satisfactory technical success and primary patency rates (100% and 93.8%, respectively) were observed with the ST in this study. These results are superior to the ones reported for the branched iliac stent graft technique and are probably a consequence of some of the ST main features such as straightforward performance, use of only commercially available stent grafts well known by most endovascular surgeons, and the left brachial approach, which makes IIA cannulation easier. Another advantage of the ST is its versatility and flexibility to safely address AIA encumbered by adverse iliac anatomy to include (1) CIA <40 mm in length; (2) CIAA lumen <18 mm; (3) very tortuous anatomy of CIA; (4)

7 32S Lobato and Camacho-Lobato February Supplement 2013 Fig 3. Box and whiskers (max/min, mean, interquartile range) plot illustrating the evolution of the iliac aneurysm sac diameter as assessed by computed tomographic angiography (CTA) scan at 1 month and every 6 months thereafter (outliers excluded). Statistical significance was obtained only for comparisons between baseline (0 months) and 30 months (*) (P ¼.039). a distal landing zone <10 mm in length on the main internal iliac trunk; (5) ICIAA with proximal landing zone (CIA) >12 mm in diameter; (6) external iliac artery occlusion; (7) large IIAA; (8) CIA dissection complicated with CIAA (true lumen <18 mm in diameter); and (9) previous AAA open repair with Dacron graft complicated with CIA anastomotic false aneurysm. This flexibility has been clearly demonstrated in the second half of this study when the inclusion criteria were narrowed to include only AIA or ICIAA patients unfit for the IBD. Seventeen patients underwent EVAR with the ST (21 IIA ER) during the second half of the study with a technical success rate of 100% and no IIA ER occlusion. The three IIA ER occlusions reported happened in the first 18 months of the study, probably because of the technique learning curve. Various authors have highlighted the importance of the learning curve to reach a result plateau for EVAR After the learning curve period, we understood that the Viabahn (W. L. Gore & Associates, Inc) should not be landed too distally in any IIA secondary branch less than 4 mm in diameter. Another technical advantage of the ST is the deployment of the bridge stent in the IIA through a brachial access. This enabled us to catheterize the IIA in 100% of the cases, even in the presence of very tortuous CIA anatomy, as opposed to the difficulties reported for the IBD. 24,26 There are concerns, though, that brachial puncture may lead to brachial artery thrombosis, which in fact happened in 5% of cases. This was attributed to a delay in removing the brachial sheath. Both cases were successfully managed conservatively. Another issue relates to the risk of stroke. 26 This complication has been reported rarely for this type of access and did not occur in our study. One ipsilateral iliac occlusion was likely a consequence of the higher radial force of the SECS used (Viabahn mm) in comparison to the Excluder iliac stent graft extension, culminating in the latter external compression and occlusion. The problem was easily solved after thromboembolectomy followed by a self-expandable bare stent deployment ( mm) inside the Excluder iliac limb stent graft. Another patient presented with contralateral iliac occlusion (to IIA ER) at the 29th postoperative day because of a previous iatrogenic dissection not addressed during the sandwich procedure. Patency was restored through thromboemboletomy and profundoplasty followed by self-expandable bare stent deployment. The low occlusion rate of the iliac branches with landing zones in the external iliac arteries, especially the very tortuous ones, as observed in this series, is probably a result of the freedom to choose the more adequate stent graft among all commercially available ones, a hallmark of the ST. As a rule of thumb, we use either Aorfix (Lombard Medical, Oxon, UK) or Endurant (Medtronic Vascular, Santa Rosa, Calif) for the very tortuous CIA anatomy. A very important issue with EVAR is cost, particularly as it compares with AAA open repair As previously mentioned, the trifurcated endograft technique for IIA preservation 21 is an expensive option as a beside-the-bridge cover stent to IIA ER. It requires two main body stent grafts to accomplish it. A similar scenario is also true for the branched iliac stent graft as a beyond-the-bridge cover stent to IIA. It also requires an IBD, an aortic bifurcated Zenith stent graft (Cook Inc, Bloomington, Ind), and other subsidiary endovascular devices. The ST is a more economic option. During the present study, a total of 48 IIA/IIAA were endorevascularized using a bridge cover stent to IIA, an aortic bifurcated stent graft (main body and contralateral iliac limb), and one iliac extension for each IIA ER. The reduction of one additional mainbody stent graft or one IBD has a considerable impact on procedural costs. The Viabahn is the covered stent selected for the ST because of its flexibility and length (minimum of 100 mm is recommended). To avoid undesirable endoleaks, a 50-mm overlap with the iliac stent graft extension is recommended. Because of this shortcoming, other commercially available covered stents (Advanta V12; Atrium Medical Corporation, Hudson, NH, and Fluency; Bard Inc, Murray Hill, NJ) are considered inappropriate. Actually, the ideal covered stent for the sandwich procedure would also have radiopaque marks and tapered design. Early and late buttock claudication rates for the IIA ER were low (4.2% and 0%, respectively) compared with the IIA coil embolization occlusion group (57.1% and 14.3%, respectively). This finding highlights the importance of preserving pelvic flow to at least one IIA.

8 Volume 57, Number 2S Lobato and Camacho-Lobato 33S The presence of nondialysis-dependent chronic renal insufficiency (15%) was quite high in this group of patients, as four patients with previous chronic renal insufficiency and one with previous normal renal function had further impairment of their renal function during the postoperative period. This could be attributed to the volume of contrast used in the first 18 months of the study. We managed to reduce the mean contrast volume to 70 ml during the last 12 months of the study and had no further or initial impairment of renal function in the last 17 patients submitted to the ST during this period. We had one late persistent type II endoleak with a 5 mm increase in the CIAA sac, probably because of backflow from the gluteal artery that was not coiled intraoperatively. This observation led us to conclude that when deploying an SECS in IIA secondary branch, it is advisable to coil the others feeding arteries. Midterm outcomes of the ST are very encouraging and suggest that we are going in the right direction to accomplish our initial goal of overcoming current anatomic and device constraints to expand the limits of EVAR in a safe, easy-to-perform, and cost-effective manner. The ST appears to be a promising tool in the EVAR armamentarium and more experience with the method is advisable. AUTHOR CONTRIBUTIONS Conception and design: AL Analysis and interpretation: AL, LL Data collection: AL Writing the article: AL, LL Critical revision of the article: LL Final approval of the article: AL Statistical analysis: LL Obtained funding: Not applicable Overall responsibility: AL REFERENCES 1. EVAR trial participants. Endovascular aneurysm repair versus open repair in patients with abdominal aortic aneurysm (EVAR trial 1): randomised controlled trial. Lancet 2005;365: Blankensteijn JD, de Jong SE, Prinssen M, van der Ham AC, Buth J, van Sterkenburg SM, et al. Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms. N Engl J Med 2005;352: Lederle FA, Freischlag JA, Kyriakides TC, Padberg FT Jr, Matsumura JS, Kohler TR, et al. Outcomes following endovascular vs open repair of abdominal aortic aneurysm: A randomized trial. JAMA 2009;302: Armon MP, Wenham PW, Whitaker SC, Gregson RH, Hopkinson BR. Common iliac artery aneurysms in patients with abdominal aortic aneurysms. Eur J Vasc Endovasc Surg 1998;15: Cheng SW, Ting AC, Ho P, Poon JT. Aortic aneurysm morphology in Asians: features affecting stent graft application and design. J Endovasc Ther 2004;11: Heikkinen MA, Alsac JM, Arko FR, Metsänoja R, Zvaigzne A, Zarins CK. The importance of iliac fixation in prevention of stent graft migration. J Vasc Surg 2006;43: Razavi MK, DeGroot M, Olcott C 3rd, Sze D, Kee S, Semba CP, et al. Internal iliac artery embolization in stent graft treatment of aortoiliac aneurysms: analysis of outcomes and complications. J Vasc Interv Radiol 2000;11: Karch LA, Hodgson KJ, Mattos MA, Bohannon WT, Ramsey DE, McLafferty RB. Adverse consequences of internal iliac artery occlusion during endovascular repair of abdominal aortic aneurysms. J Vasc Surg 2000;32: Yano OJ, Morrissey N, Eisen L, Faries PL, Soundararajan K, Wan S, et al. Intentional internal iliac artery occlusion to facilitate endovascular repair of aortoiliac aneurysms. J Vasc Surg 2001;34: Farahmand P, Becquemin JP, Desgranges P, Allaire E, Marzelle J, Roudot-Thoraval F. Is hypogastric artery embolization during endovascular aortoiliac aneurysm repair (EVAR) innocuous and useful? Eur J Vasc Endovasc Surg 2008;35: Rayt HS, Bown MJ, Lambert KV, Fishwick NG, McCarthy MJ, London NJ, et al. Buttock claudication and erectile dysfunction after internal iliac artery embolization in patients prior to endovascular aortic aneurysm repair. Cardiovasc Intervent Radiol 2008;31: Mehta M, Veith FJ, Ohki T, Cynamon J, Goldstein K, Suggs WD, et al. Unilateral and bilateral hypogastric artery interruption during aortoiliac aneurysm repair in 154 patients: a relatively innocuous procedure. J Vasc Surg 2001;33:S Parodi JC, Ferreira M. Relocation of the iliac artery bifurcation to facilitate endoluminal treatment of abdominal aortic aneurysms. J Endovasc Surg 1999;6: Faries PL, Morrissey N, Burks JA, Gravereaux E, Kerstein MD, Teodorescu VJ, et al. Internal iliac artery revascularization as an adjunct to endovascular repair of aortoiliac aneurysms. J Vasc Surg 2001;34: Mertens RA, Bergoeing MP, Mariné LA, Valdés F, Krämer AH. Antegrade hypogastric revascularization during endovascular aortoiliac aneurysm repair: an alternative to bilateral embolization. Ann Vasc Surg 2010;24:255.e Bergamini RM, Rachel ES, Kinney EV, Jung MT, Kaebnick HW, Mitchell RA. External iliac artery-to-internal iliac artery endograft: A novel approach to preserve pelvic inflow in aortoiliac stent grafting. J Vasc Surg 2002;35: Criado FJ, Wilson EP, Velazquez OC, Carpenter JP, Barker C, Wellons E, et al. Safety of coil embolization of the internal iliac artery in endovascular grafting of abdominal aortic aneurysms. J Vasc Surg 2000;32: Gough MJ, MacMahon MJ. A minimally invasive technique allowing ligation of the internal iliac artery during endovascular repair of aortic aneurysms with an aortouniiliac device. Eur J Vasc Endovasc Surg 1998;16: Karch LA, Hodgson KJ, Mattos MA, Bohannon WT, Ramsey DE, McLafferty RB. Management of ectatic, nonaneurysmal iliac arteries during endoluminal aortic aneurysm repair. J Vasc Surg 2001;33: S Torsello G, Schonefeld E, Osada N, Austermann M, Pennekamp C, Donas KP. Endovascular treatment of common iliac artery aneurysms using the bell-bottom technique: long-term results. J Endovasc Ther 2010;17: Minion DJ, Xenos E, Sorial E, Saha S, Endean ED. The trifurcated endograft technique for hypogastric preservation during endovascular aneurysm repair. J Vasc Surg 2008;47: Greenberg RK, West K, Pfaff K, Foster J, Skender D, Haulon S, et al. Beyond the aortic bifurcation: branched endovascular grafts for thoracoabdominal and aortoiliac aneurysms. J Vasc Surg 2006;43: Malina M, Dirven M, Sonesson B, Resch T, Dias N, Ivancev K. Feasibility of a branched stent-graft in common iliac artery aneurysms. J Endovasc Ther 2006;13: Verzini F, Parlani G, Romano L, De Rango P, Panuccio G, Cao P. Endovascular treatment of iliac aneurysm: concurrent comparison of side branch endograft versus hypogastric exclusion. J Vasc Surg 2009; 49: Pua U, Tan K, Rubin BB, Sniderman KW, Rajan DK, Oreopoulos GD, et al. Iliac branch graft in the treatment of complex aortoiliac aneurysms: early results from a North American institution. J Vasc Interv Radiol 2011;22:542-9.

9 34S Lobato and Camacho-Lobato February Supplement Ziegler P, Avgerinos ED, Umscheid T, Perdikides T, Erz K, Stelter WJ. Branched iliac bifurcation: 6 years experience with endovascular preservation of internal iliac artery flow. J Vasc Surg 2007;46: Parodi JC, Parodi FE. The sandwich technique to preserve the hypogastric artery during EVAR. J Endovasc Ther 2011;18: Lobato AC. Sandwich technique for aortoiliac aneurysms extending to the internal iliac artery or isolated common/internal iliac artery aneurysms: a new endovascular approach to preserve pelvic circulation. J Endovasc Ther 2011;18: Falkensammer J, Hakaim AG, Oldenburg WA, Neuhauser B, Paz- Fumagalli R, McKinney JM, et al. Natural history of the iliac arteries after endovascular abdominal aortic aneurysm repair and suitability of ectatic iliac arteries as a distal sealing zone. J Endovasc Ther 2007;14: Lee WA, Wolf YG, Hill BB, Cipriano P, Fogarty TJ, Zarins CK. The first 150 endovascular AAA repairs at a single institution: how steep is the learning curve? J Endovasc Ther 2002;9: Forbes TL, DeRose G, Kribs SW, Harris KA. Cumulative sum failure analysis of the learning curve with endovascular abdominal aortic aneurysm repair. J Vasc Surg 2004;39: Lobato AC, Rodriguez-Lopez J, Diethrich EB. Learning curve for endovascular abdominal aortic aneurysm repair: evaluation of a 277- patient single-center experience. J Endovasc Ther 2002;9: Bosch JL, Kaufman JA, Beinfeld MT, Adriaensen ME, Brewster DC, Gazelle GS. Abdominal aortic aneurysms: cost-effectiveness of elective endovascular and open surgical repair. Radiology 2002;225: Blackhouse G, Hopkins R, Bowen JM, De Rose G, Novick T, Tarride JE, et al. A cost-effectiveness model comparing endovascular repair to open surgical repair of abdominal aortic aneurysms in Canada. Value Health 2009;12: Tarride JE, Blackhouse G, De Rose G, Novick T, Bowen JM, Hopkins R, et al. Cost-effectiveness analysis of elective endovascular repair compared with open surgical repair of abdominal aortic aneurysms for patients at a high surgical risk: a 1-year patient-level analysis conducted in Ontario, Canada. J Vasc Surg 2008;48: Prinssen M, Buskens E, de Jong SE, Buth J, Mackaay AJ, van Sambeek MR, et al. Cost-effectiveness of conventional and endovascular repair of abdominal aortic aneurysms: results of a randomized trial. J Vasc Surg 2007;46: Submitted Dec 11, 2011; accepted Sep 29, 2012.