Iliac branch device results show value of internal iliac artery revascularisation

Darren Schneider
Darren Schneider

The new Excluder iliac branch endoprosthesis (Gore) is safe and effective at treating aortoiliac aneurysms and common iliac artery aneurysms, maintaining blood flow into the internal iliac artery, and preventing the complications associated with internal iliac artery sacrifice, Darren Schneider, New York, USA, told delegates at the Vascular Annual Meeting (9–11 June, National Harbor, USA). Another study, with the Cook Medical Zenith Branch Endovascular Graft – Iliac Bifurcation, showed minimal additional perioperative time, no increase in perioperative morbidity and excellent long-term branch patency with the device.

Internal iliac (or hypogastric) artery occlusion during the endovascular aneurysm repair (EVAR) is associated with an increased risk of buttock claudication, colonic and spinal cord ischaemia, and sexual dysfunction. The more common complications—buttock claudication and sexual dysfunction—are reported at rates of up to 27% and 15%, respectively, and represent major quality of life issues. Methods of achieving internal iliac artery preservation include open surgical bypass, parallel endograft techniques, bell-bottom grafts and iliac branched endografts. However, there has been a lack of long-term assessment of outcomes of these methods.

Schneider, Weill Cornell Medical College, New York, USA, and national principal investigator of the Excluder iliac branch endoprosthesis US pivotal trial, presented six-month outcomes of the device, telling delegates, “Iliac artery aneurysms are common. In the EUROSTAR database (Hobo et al, 2008), out of over 6,200 patients, 28% had associated iliac artery aneurysms, and when compared to patients undergoing EVAR who did not have common iliac artery aneurysms, those who did had a higher rate of occlusions, endoleaks, reinterventions and aneurysm ruptures.”

The research team enrolled 65 patients with aortoiliac or common iliac aneurysms, of which 64 patients underwent implantation of the Excluder device at 28 US centres from 2013 to 2015 (98.4% male patients, median age 69.5 years). All patients underwent placement of a single device. Twenty-two patients (34.4%) with bilateral common iliac arteries were enrolled after staged coil or plug embolisation (n=21) or surgical revascularisation (n=1) of the contralateral internal iliac artery. Follow-up at 30 days and six months included clinical assessment and computed tomography (CT) angiography evaluation as assessed by an independent core laboratory. The primary effectiveness endpoint was freedom from limb occlusion and reintervention for type I or III endoleak and ≥60% device occlusion at six months. The secondary effectiveness endpoint was freedom from new onset of buttock claudication on the endoprosthesis side at six months.

Thirty-nine (60.9%) patients had unilateral common iliac aneurysms and 25 (39.1%) patients had bilateral common iliac aneurysm. Mean common iliac aneurysm diameter on the endoprosthesis side was 41mm. Twenty-five (39.1%) patients also had an abdominal aortic aneurysm with a diameter >50mm (mean 58.5mm). Overall technical success (successful deployment and patency of all IBE components and freedom from type I or III endoleak) was 95.2% and there was no procedural mortality.

Data from 61 patients was available for endpoint analysis. Internal iliac limb patency was 95.1% and there were no new type I or III endoleaks or device migrations observed at six months. The three patients with loss of internal iliac limb patency were asymptomatic and freedom from new onset buttock claudication on the endoprosthesis side was 100% at six months. New onset buttock claudication occurred on the non-endoprosthesis treatment side in 28.6% (n=6) of patients who underwent staged coil embolisation of the contralateral internal iliac artery.

“Internal iliac artery preservation using the iliac branch endoprosthesis is feasible with high rates of technical success and safety, 95% patency at six month and freedom from new onset claudication,” Schneider said. He closed by telling the audience that follow-up will be continued for five years to establish the long-term durability of iliac aneurysm repair with the Excluder device.

Internal iliac artery preservation vs. coverage

In another presentation Mohammed Abbasi, Cleveland Clinic, Cleveland, USA, spoke about the experience of his centre in comparing long-term outcomes of EVAR with and without internal iliac artery branch incorporation in 337 patients from 1999 to 2013 (255 EVAR and 82 EVAR plus hypogastric artery branch incorporation—EVAR-H). Employing the Cook Zenith endoprosthesis with iliac bifurcation as part of a physician-sponsored IDE study, Abbasi and colleagues assessed mortality and aneurysm-related mortality as primary outcome measures, as well as perioperative mortality, freedom from reintervention, rates of endoleak and branch patency as secondary outcome measures.

Patients in the EVAR group were older (mean 75.5 years vs. 71.5 years for the EVAR-H group, p<0.001), had a higher rate of congenital heart failure (24.3% vs. 12.2%, p=0.02) and had a higher rate of chronic obstructive pulmonary disease (35.3% vs. 22%, p=0.024). In the EVAR-H group, there was a significantly higher rate of previous aneurysm repair (20.7% vs. 0.4%, p<0.001).

Abbasi reported that perioperative morbidity did not differ significantly between the two groups (12.9% EVAR vs. 9.7% EVAR-H, p=0.4), although procedural duration for EVAR-H (mean of 3.7 hours) was higher than in the EVAR group (2.6 hours) (p<0.001). Freedom from all-cause mortality, however, was noticeably improved in the EVAR-H group. At one year after treatment, EVAR-H freedom from all-cause mortality was 94%, compared to 88% in the EVAR group. This superiority persisted at three years (85% vs. 70%) and five years (64% vs. 50%) (all p=0.02). Freedom from abdominal aortic aneurysm-related mortality, however, was not different between the two groups (99% for both groups at one year, 99% for EVAR-H and 98% for EVAR at three years, and 99% for EVAR-H and 98% for EVAR at five years; p=0.84). Similarly, freedom from secondary intervention was not different between the two groups (83% for EVAR-H and 90% for EVAR at one year, 80% for EVAR-H and 81% for EVAR at three years, and 77% for EVAR-H and 79% for EVAR at five years; all p=0.66).

Total endoleak rate across both groups was 7.4%; 8.2% in the EVAR group and 4.9% in the EVAR-H group (p=0.31). Other reasons for secondary interventions included limb thrombosis (2.7% overall; 2% for EVAR and 4.9% for EVAR-H; p=0.22), device migration (1.2% overall; 1.6% for EVAR and 0% for EVAR-H; p=0.57) and component separation (2.7% overall; 3.5% for EVAR and 0% for EVAR-H; p=0.12). Freedom from endoleak was no different between the two groups (70% EVAR-H vs. 79% EVAR at one year, 70% for EVAR-H vs. 76% for EVAR at three years, and 70% for EVAR-H vs. 75% for EVAR at five years; p=0.37).

Abbasi told the audience that hypogastric branch vessel patency was 96% for EVAR-H at 10 years, with the bifurcated-bifurcated device that was used showing a patency of 100% at seven years.

Zenith and iCAST combination

Another study presented at the Vascular Annual Meeting show that, at six months, the Zenith iliac branch graft (Cook Medical) is safe and effective when combined with an iCAST covered stent (Atrium) to maintain hypogastric artery perfusion during endovascular aneurysm repair (EVAR) in patients with aortoiliac or iliac aneurysms and unsuitable distal landing zones within the common iliac artery.

Patients with aortoiliac, or isolated iliac, artery aneurysms “frequently lack suitable distal landing zones during EVAR,” said W Anthony Lee, Boca Raton Regional Hospital, Boca Raton, USA, presenting his group’s data. The options for these patients are limited, with potential hypogastric artery occlusion or an adjunctive surgical or endovascular procedure to maintain hypogastric perfusion. However, surgical procedures such as a hypogastric bypass are associated with increased morbidity to overall treatment. Acute hypogastric occlusions is associated with a 30–40% risk of pelvic ischaemia symptoms and complications, Lee said, including buttock claudication and sexual dysfunction.

The study was a prospective, non-randomised, multicentre investigation enrolling subjects with an aortoiliac or iliac aneurysm and an unsuitable distal landing zone (length <10mm or diameter >20mm) to be treated with the Zenith graft—an off-the-shelf, branched graft with a proximal common iliac artery junctional segment (12 ×17mm or 31mm), hypogastric artery side-branch, and an external iliac artery segment. The graft is delivered via femoral access in a 20Fr sheath (7.7mm outer diameter) that includes a preloaded catheter to facilitate cannulation of the side-branch. The primary endpoint was six-month freedom from patency-related intervention for the hypogastric artery. All imaging were reviewed by an independent core lab.

The study enrolled 40 patients (38 male and two females) with a mean age of 67.8±9 years at 18 US sites. Iliac aneurysms were bilateral in 25 (62.5%) cases and the mean common iliac artery diameter treated was 37±11mm. Deployment success was 100% with a mean procedure time of 167±48 minutes. There was no 30-day mortality. Mean follow-up was 12.2±3.8 (range of 2–20) months. One death occurred at 167 days due to pre-existing congestive heart failure. There was no aneurysm rupture, conversion to open repair, type I or III endoleak, device migration, or stent fracture. Hypogastric artery side-branch patency was 100% with available CT follow-up. Four subjects (10%) required second interventions, none of which were related to the hypogastric artery side-branch: one for common iliac artery segment stenosis and two for external iliac artery segment occlusion. One subject had multiple secondary interventions related to contralateral hypogastric artery embolisation. Overall Zenith graft six-month patency was 95%. Two subjects experienced new impotence (at nine and 196 days), while there were no cases of renal insufficiency, renal failure requiring dialysis, or buttock claudication.

“Initial results are favourable in supporting the safety and effectiveness of the Zenith iliac branch graft in combination with the Atrium iCAST covered stent in preserving hypogastric artery perfusion during EVAR in patients with aortoiliac or iliac aneurysms and unsuitable distal landing zone within the common iliac artery,” concluded Lee.