Technical Feasibility and Safety of a Snare-Less,EVAR–First Technique for Iliac Branch Endoprosthesis

Snare-Less, EVAR-First Technique (SET) Group

Standard percutaneous EVAR is first performed using an aortic endograft of choice, with iliac limb extensions to bilateral iliac bifurcations (Figure 1A–F). Ipsilateral to the target CIA/IIA aneurysm, the IBE is advanced retrograde via femoral access over a Lunderquist Extra-Stiff wire (Cook Medical) and partially deployed until the side branch is released, per manufacturer’s protocol. Adequate overlap into the previously placed EVAR limb extension is ensured. From the contralateral groin, a Heli-FX Guide 22 or 28 mm steerable sheath (Medtronic Aortic, Inc, Santa Rosa, California) is advanced and positioned at the aortic endograft flow-divider. The tip is angled 180° (Figure 1B). Through the Heli-FX, a Glidewire (Terumo Medical Corporation, Somerset, New Jersey) and the Berenstein catheter are advanced over the flow-divider and used to select the side branch followed by the native IIA (Figure 1C). Wire and catheter are advanced well into an IIA branch, and exchange is made for a Rosen wire (Cook Medical) or a flexible-tip Amplatz Super Stiff wire (Boston Scientific Corporation, Boston, Massachusetts). A Viabahn Balloon-Expandable Endoprosthesis (VBX; W. L. Gore & Associates, Inc) is advanced through the Heli-FX over the stiff wire and positioned and deployed into the IIA or IIA branch, ensuring adequate distal seal. A second VBX is deployed if needed for adequate overlap into the IBE side branch. Self-expanding Viabahn Endoprosthesis (W.L. Gore & Associates, Inc) is used in cases of significant IIA tortuosity. The remainder of the IBE is deployed into the external iliac artery (EIA), and an additional EIA stent is added if necessary for adequate distal seal within the EIA (Figure 1D). Kissing balloon angioplasty of the IIA and EIA is performed (Figure 1E). Reliant (Medtronic Aortic, Inc) balloon angioplasty of the IBE and EVAR limb overlap segment is performed.

OPEN IN VIEWER

Figure 1.

(A) Initial aortic angiography of a 45 mm right common iliac artery (CIA) aneurysm; (B) after standard endovascular abdominal aortic aneurysm repair (EVAR) is performed, the iliac branch endoprosthesis (IBE) is deployed on the ipsilateral side to release the side branch; the Heli-FX Guide steerable sheath is then inserted from the contralateral groin, and the stiff tip is angled 180° to traverse the endograft flow-divider; (C) in left anterior oblique projection, the side branch and native internal iliac artery (IIA) are selected; (D) after exchange for a stiff wire with an atraumatic tip, a balloon-expandable stent is deployed into the IIA with adequate overlap into the side branch; (E) kissing balloon angioplasty of the external and internal iliac arteries is performed; (F) completion angiography demonstrates exclusion of the CIA aneurysm with preservation of the IIA.

Standard Group

Patients in this group underwent standard IBE deployment per manufacturer protocol using a through-and-through femoral wire if they did not have a pre-existing aortic graft. Those who had undergone previous open or endovascular aortic repair underwent unilateral femoral access for IBE delivery and brachial/axillary access for IIA cannulation and stent graft delivery.

Follow-up

Routine postoperative imaging protocol was computed tomography angiography (CTA) with venous delay at 1, 6, and 12 months, followed by annual non-contrast CT and ultrasound sonography (US). Primary endpoints were technical success, major adverse events, mortality, reintervention, IIA patency, and freedom from IIA branch instability. Technical success was defined by successful deployment of both the EVAR and the IBE with maintained patency of the IIA and no stent graft migration. Major adverse events included mortality, myocardial infarction, stroke, renal failure, bleeding requiring transfusion, respiratory failure, and bowel ischemia. Internal iliac artery branch instability was a composite outcome, which included branch occlusion, stenosis, component separation, endoleak, and the need for any branch-related reintervention. ¹⁰

Statistics

Continuous variables were described using medians and interquartile range (IQR). Categorical variables are presented in numbers (percentage). Comparison of independent groups was performed using the Mann-Whitney U test for continuous variables or the Fischer exact test for categorical variables. Follow-up time for endoleak, reintervention, and death were defined as the time from the index operation to the date of the outcome, date of death, or date of lost to follow-up. Lost to follow-up was defined as missing 1 or more scheduled imaging studies with no further radiological or clinical follow-up. All follow-up data mentioned are based on radiological follow-up, except for mortality, which is based on clinical follow-up. Analyses were performed using R software version 4.1.1 (The R Foundation, Vienna, Austria).

30-Day Follow-up

At 30 days, there were no mortalities or major adverse events in either group. There were 100% IIA patency, no IIA instability, and no reinterventions.

Subsequent Follow-up

Median follow-up in the SET group was 5.7 (5.5-6.2) months. One patient in the SET group died at 6 months postoperative, cause unknown. He had a CTA 1 month prior to his death demonstrating complete thrombosis of his left CIA aneurysm and patent IIA and branches with no endoleak. One patient developed a type 1B endoleak at 6 months and is scheduled for IIA limb extension. The remaining 3 patients in the SET group each have radiological follow-up of 5 to 6 months demonstrating patent IIA, no IIA instability, and no endoleaks.

Median follow-up for the Standard group was 1.6 years [IQR=0.8-2.1]. One patient developed a type 1B endoleak with CIA expansion at 3 months; however, given her worsening dementia and functional status, her family elected for hospice care. She ultimately died 3 months later, reportedly from complications related to worsening dementia. Another patient died after hemorrhagic stroke 7 months postoperative. He had a scan 1 month prior to his death which demonstrated patent IIA with no IIA endoleak. In the remaining 13 patients, there were no deaths or major adverse events within the first year. Imaging at 1 year for these surviving 13 patients demonstrated patent IIA and branches with no IIA instability. There were no reinterventions.

Heli-FX Guide

The critical piece in this technique is the use of a steerable sheath with a stiff, deflectable tip that makes a wide 180° turn—in this case, the Heli-FX Guide (originally designed for use with EndoAnchor technology). This is a 16F sheath with a 62 cm working length and a tip that is sturdy enough and wide enough to allow passage of a large VBX on a 180° turn. In our experience, the deflected tips on the Destino (Oscor, Palm Harbor, Florida) and TourGuide (Medtronic Aortic, Inc) steerable sheaths make angles that are too acute and lack adequate stiffness to allow a 7 to 8F balloon-mounted stent to stably make a sharp hairpin turn.

Benefits of EVAR Before IBE

As we have previously described, placement of an EVAR prior to IBE placement creates a “docking limb” in which to land the main body of the IBE.^8,9 In the past, when placing EVAR before IBE, we limited ourselves to placement of an AFX2 endograft because it preserved the native aortic bifurcation, allowing us to proceed with snaring and standard deployment of the IBE. Patients who received this approach had to be anatomically suited for the AFX2 endograft. The purpose of through-and-through femoral access is to create a platform stiff enough to allow up-and-over advancement of a large bore sheath into the iliac side branch. In SET for IBE, with a stiff sheath tip that deflects across the aortic bifurcation to easily support wire, catheter, and stent passage, there is no further need for through- wire access. EVAR can be placed first, and the IBE landed anywhere within the iliac limb. This subsequently eliminates the renal-to-iliac bifurcation length requirement for IBE.

SET for IBE also eliminates the need for upper extremity access in cases where patients present with an EVAR already in place. While other techniques have been reported to address the challenge of groin-only access to place an IBE within a pre-existing aortic endograft, these complex solutions are not practical for routine use.^11–13 For example, Dawson et al describes a “push-and-pull” maneuver that requires mating one sheath into another from opposite groins over a through wire, then moving both sheaths together as a unit to traverse the flow-divider. The technique is described in numerous panels that appear to add complexity to IBE placement. SET follows the same concept of protecting the flow-divider, done simply via a well-supported steerable sheath.

Limitations of this study include the small sample size in the SET group. While the feasibility of SET is promising in this limited study, a larger experience would further solidify our findings. In addition, our experience is exclusively with VBX and Viabahn stents. VBX is the senior author’s preferred balloon-expandable stent. Other balloon-expandable stent grafts available in the United States tend to be more rigid and less able to handle tortuosity; with non-VBX stent grafts, we have on occasion experienced separation of the stent from its mounted balloon prior to deployment. We further acknowledge that this technique does hinge on the Heli-FX, which may not be available in all countries. Finally, we add that given the novelty of the technique, available follow-up for the SET group is short, but the method of IIA stent delivery (via a snared vs non-snared platform) is unlikely to have an impact on long-term metrics for IIA stability.