Management of aortoiliac aneurysms by retrograde endovascular hypogastric artery preservation

Introduction

Complex aortoiliac aneurysms (AIAs) have traditionally been treated by embolization of the hypogastric artery (HA), followed by extension of the bifurcated endograft into the external iliac artery (EIA), ¹ shifting the distal sealing zone to the EIA. However, embolization of the HA has been associated with hip and buttock claudication, impotence, colonic ischemia, paraplegia and pelvic necrosis. ² Observation of these complications has stimulated development of new endovascular techniques that allow the achievement of distal sealing, such as the bell-bottom technique,^3,4 iliac branched endograft placement ⁵ and the sandwich technique. ⁶

One procedure that has been developed to overcome many of the challenges faced when performing endovascular aortoiliac aneurysm repair (EVAR) is retrograde endovascular hypogastric artery preservation (REHAP). ⁷ This technique aims to preserve pelvic perfusion and to achieve exclusion of iliac aneurysms by inserting an aortouniiliac endograft on the ipsilateral side with a crossover bypass and linking the contralateral HA and EIA with an endograft. ⁸ Some authors have reported use of the Gore Viabahn endoprosthesis (Gore Medical, Flagstaff, AZ, USA) as part of the REHAP procedure.^8–10

We thus sought to determine the safety and efficacy of this technique by analyzing the perioperative and long-term postoperative outcomes of 12 AIA patients who had undergone EVAR with aortouniiliac endografting and REHAP with the Gore Viabahn device.

Methods

This study methodology and design was approved by the institutional research ethics committee.

All patients treated electively with AIA from January 2004 to January 2011 at our institution were retrospectively identified from a prospectively maintained database. Additional patient information, including demographics, co-morbidities and outcome variables, were obtained through review of clinical records. Only patients presenting with AIAs and considered to be at high risk for open surgical repair were included for participation in the study.

Preoperative images were obtained by high-resolution spiral computed tomography (Toshiba Activion 16, Tokyo, Japan) performed with 1-mm collimation and 0.8–1.2 pitch and then reconstructed at 0.8-mm intervals. The images were subsequently used for device planning, performed on a Vitrea 3-D workstation (Vital Images, Minnetonka, MN, USA). Postoperative images were obtained one and six months postoperatively and once a year thereafter to evaluate the patency of the contralateral HA, aneurysm diameter and presence of endoleaks. Technical success was defined as successful device placement without endoleaks and survival for 24 hours after surgery.

All patients received prophylactic antibiotic therapy before surgery and had large-bore intravenous catheters, radial artery catheters and Foley catheters in place. All received general endotracheal anesthesia and were provided intravenous heparin during the procedure. After the femoral arteries were exposed, an Apollo endograft (Nano Endoluminal, Florianópolis, Brazil) aortouniiliac device was inserted over a Lunderquist wire in all patients (Figure 1). This device has a polytetrafluoroethylene (PTFE) and nitinol-based platform and a free-flow, barbed proximal stent. The aortouniiliac endograft was extended to the EIA in three cases in which the ipsilateral HA had been coil embolized as a result of the presence of bilateral common iliac artery (CIA) aneurysms. The contralateral HA was cannulated with a VS1 catheter and a hydrophilic guide wire and replaced with a stiff wire. Wire access was established via a long hydrophilic sheath advanced over the HA until resistance could be detected. OPEN IN VIEWER

The Viabahn device was advanced and positioned under fluoroscopy from the EIA into the HA. An angioplasty balloon was inserted to accommodate the device in all cases (Figure 2), and angiography was performed. Finally, a femorofemoral bypass was constructed with an 8-mm Dacron graft and completion angiography performed to confirm exclusion of the aneurysm (Figure 3). After surgery, all patients were transferred to intensive care. OPEN IN VIEWER

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Figure 3

Intraoperative angiography demonstrating femorofemoral bypass and external iliac to hypogastric Viabahn device in place

Postoperative radiographic follow-up consisted of postprocedural CT scans at one, 12 months and annually thereafter. Duplex ultrasound was performed at six months and annually thereafter.

Results

Twelve patients (mean age 77 years, range 64–86 years) underwent elective EVAR via aortouniiliac endografting and the REHAP technique. The characteristics of the patients enrolled onto this retrospective study are listed in Table 1. The mean time of follow-up was 147 weeks. The mean diameter of abdominal aortic aneurysms was 56.25 mm (range 27–98 mm), and that of CIA aneurysms was 24.2 mm (range 9–49 mm). All patients had fusiform aneurysms, with the exception of one patient, who had a late right iliac paraanastomotic aneurysm after aortobiiliac bypass. Within an average follow-up interval of 162 weeks (range 17–369 weeks), abdominal aortic aneurysm diameter decreased by 1.91 mm (range 22−15 mm), and CIA diameter by 0.91 mm (range 12−2 mm).

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Table 1

Characteristics of 12 patients

Characteristic	Value
Sex (M:F)	11:1
Age, year, mean (range)	77 (64–86)
Co-morbidity, n (%)
Coronary artery disease	8 (66.7)
Hypertension	10 (83.3)
Pulmonary disease	3 (25.0)
Renal disease	3 (25.0)
Diabetes mellitus	1 (8.3)
Hyperlipidemia	4 (33.3)
Smoking	3 (25.0)
Hostile abdomen	1 (8.3)
AAA diameter, mm, mean (range)	56.25 (27–98)
CIA diameter (24 vessels), mm, mean (range)	24.2 (9–49)

All endografts were deployed in the intended position, and technical success was achieved in all cases. The mean diameter of the EIA on the REHAP side was 9.5 mm (range 7–12 mm), the mean HA diameter on this side was 8.6 mm (range 5–12 mm) and the mean Viabahn diameter was 9.0 mm (range 8–13 mm). All the Viabahn prosthesis were 10 cm length. All Viabahn devices were deployed at the intended position and none of them kinked.

During the follow-up period, no patients exhibited endoleak related to the Viabahn device or occlusion of implanted components. One patient who presented with a type Ib endoleak related to the aortouniiliac device 360 weeks after implantation was treated with placement of a distal endograft extension. Three patients presented with type II endoleak detected at the first control computed tomographic scan; two of those did not have expansion of the aneurysmal sac, and one patient was lost to follow-up. No patients had any clinical evidence of hip and/or buttock claudication, colon ischemia or spinal cord ischemia during follow-up, and there were no aneurysm-related deaths. Secondary interventions were not required in any patient.

Discussion

Endovascular repair of abdominal aortic aneurysms is a well-established technique with good long-term results. ¹¹ However, the applicability of EVAR depends on anatomic features. ¹² In 15–30% of cases, an infrarenal abdominal aortic aneurysm may be associated with CIA dilation or aneurysm.^13–15 Several techniques are currently used to address the challenge presented by aortoiliac morphology and achieve distal sealing during EVAR. ¹⁶ These techniques include embolization of the ipsilateral HA with extension of the endograft limb into the EIA, placement of large devices in the iliac arteries (the bell-bottom technique), advancement of the CIA bifurcation with HA bypass/transposition, use of branched endografts, the sandwich technique and use of an aortouniiliac endograft with femorofemoral bypass in combination with retrograde endovascular external HA bypass.

Previous reports have highlighted the fact that many patients experience complications after HA embolization, including buttock claudication, sexual dysfunction, skin necrosis of the buttocks, sciatic nerve ischemia, colonic ischemia and paraplegia.^1,17–21 Buttock claudication seems to be the most common symptom, affecting 13–58% of HA embolization patients.^22,23

In the first report on the use of aortic cuffs for treatment of ectatic CIA aneurysms, Karch et al. ¹³ favorably compared the technique with HA overstenting or coil embolization. Although large-diameter iliac limbs can be used to treat CIA aneurysms with acceptable results, the use of this technique is limited to iliac aneurysms up to 30 mm in diameter because of the risk of distal endoleak due to the progressive increase in diameter of the iliac artery. Several authors have reported observation of dilation of the iliac arteries after EVAR, with dilation occurring more rapidly in ectatic iliac arteries.^24–26

The implantation of branched iliac devices has been reported by some authors as having high technical success rates.^27–29 Nevertheless, Falkensammer et al. ²⁶ reported that 10.6% of the 47 patients included in their study experienced occlusion of the internal iliac side branch during follow-up after placement of a branched iliac device, while Greenberg et al. ⁵ , on an early report, identified that 15% of patients with branched iliac devices presented with acute branch thrombosis and 11% with late branch vessel thrombosis. Occlusions of the external limb have also been reported in patients with branched iliac devices. Haulon et al. ³⁰ reported three cases of external iliac occlusion in 52 patients who received a helical branched iliac device, with two cases occurring in the non-branched side and one case in the device side after occlusion of the hypogastric branch. Parlani ³¹ et al. report 91.4% patency at five years of follow-up (17 months median follow-up). Freedom from re-intervention rate was 90% at one year and 81.3% at five years.

In an intention-to-treat analysis of previous studies, Karthikesalingam et al. ³² found that clinical success rates varied from 63% to 88% within the follow-up range of the studies included in the review. Specifically, they identified 24 branched iliac device occlusions across 196 patients in all pooled series. Of the 24 patients in whom postoperative occlusions occurred, 50% (12 patients) had symptomatic buttock claudication and 21% (five patients) had symptomatic EIA occlusions. In an analysis of the proportion of patients undergoing EVAR at a single center with morphology suitable for branched iliac device implantation, Karthikesalingam et al. ⁴ found that in only 38% of cases the morphology of the target HA was compliant with the manufacturer's instructions for use.

Recently, Lobato ⁶ described the sandwich technique as the placement of a covered self-expanding stent inside the HA and an iliac endograft limb alongside an endograft positioned at the EIA. However, no late follow-up results are yet available.

Hoffer et al. ³³ described the use of an EIA-to-HA covered stent to exclude the distal aspect of a left CIA aneurysm. Derom et al. ⁸ used this method with a Viabahn stent graft to exclude bilateral CIA stump aneurysms in a patient with ligated bilateral CIA aneurysms who had received an aortic tube graft and undergone aortobifemoral bypass. In their report of four cases of aortouniiliac endografting, Bergamini et al. ³⁴ described treatment of ipsilateral CIA aneurysms by coil embolization of the internal iliac artery, extension of the endograft to the EIA and exclusion of the contralateral CIA aneurysms by a custom-made stent graft or Wallgraft (Boston Scientific, Glens Falls, NY, USA) from the EIA to the internal iliac artery. However, kinking or stenosis of the Wallgraft from a highly angulated HA takeoff is a potential complication of this technique. ⁷

The findings of this analysis of a series of AIAs treated by aortouniiliac endografting and retrograde perfusion of the contralateral HA with the Viabahn device illustrate the role of REHAP in preserving the internal iliac artery. The procedure we describe was successful for all patients examined, none experienced thrombosis of the internal or external iliac arteries, device occlusion, symptoms of pelvic ischemia or complications associated with femorofemoral bypass during follow-up. Limitations of our study include small sample size and relatively short follow-up. Our study is novel in that it is the largest series describing such a hybrid technique.

These promising results illustrate the potential of REHAP with placement of the Viabahn device in the contralateral HA in AIA cases. Longer follow-up of the outcomes of REHAP, consideration of a larger patient sample size and comparisons of this method with related techniques are required to determine its role in AIA management and treatment.