Recanalization of Occluded Iliac Artery Allowing Abdominal Aortic Aneurysm Stent Graft

Introduction

This case presents a patient scheduled to receive a femorofemoral bypass graft in conjunction with aortomonoiliac endograft. Initially, the patient was to undergo an endovascular stent graft repair for his abdominal aortic aneurysm and occluded iliac artery; however, the decision was made to recanalize the long segment occlusion and convert him to a standard bifurcated endograft. Significant literature has been published concerning monoiliac stent grafts, but there have been no reported cases of recanalizing a chronic total occlusion of the iliac with subsequent bi-limb stent graft placement.^1–5

History

The patient was a 68-year-old male with a 4 x 4 cm infrarenal abdominal aortic aneurysm (AAA) and a completely occluded right common iliac artery on magnetic resonance angiography (MRA). MRA also reported a high-grade right renal artery stenosis. The patient initially presented with severe right leg claudication of less than half of a block, relieved by rest. His leg had been swelling at night, and he denied numbness or tingling. His past medical history was significant, including 60 pack-years of smoking, non-insulin dependent diabetes, four-medication, poorly-controlled hypertension and an elevated creatinine level of 1.7. His physical exam revealed non-palpable right common femoral, popliteal and pedal dorsalis (DP) and posterior tibial (PT) pulses. As part of the routine follow-up of our vascular patients, the patient had non-invasive testing, including Doppler evaluation of the extremities, which revealed biphasic signals in the posterior tibials bilaterally.

Procedure and Findings

A staged approach was performed. The patient’s right renal artery stenosis was initially attempted from the left common femoral artery, but we were not successful because of the acute angle of the renal artery. The right renal artery, with an 80% web-like stenosis, was stented from the left brachial approach using a 6 Fr sheath. A 6 x 15 mm balloon-mounted stent was successfully placed. Approximately three weeks later, the patient returned. He was prepped and draped in the standard fashion in the operating room. Bilateral femoral arteries were then surgically exposed. An arterial sheath was placed in a retrograde access in the left common femoral artery, and a pigtail diagnostic catheter was placed in the lower abdominal aorta. Through a retrograde access in the right common femoral artery, a short 5 Fr sheath was placed. With the use of a short 5 Fr Kumpe catheter (AngioDynamics, Queensbury, New York) and 0.035-inch regular Glidewire® (Terumo, Japan), we were able to gain access through the total iliac artery occlusion. Contrast injected above revealed the catheter to be in the true lumen of the aneurysm. Once across, the lesion was dilated with a 8 mm x 4 cm PTA balloon catheter in the common iliac artery and a 7 mm x 4 cm balloon catheter in the external iliac artery.

Before committing to the standard bifurcated endograft, a CardioMEMS 16 introducer sheath (Atlanta, Georgia) was advanced through the recanalized iliac system. Using the right iliac approach, the CardioMEMS sensor was then deployed in the AAA. Routine endovascular stent placement then proceeded with the deployment of the Cook Zenith stent graft (Bloomington, Illinois) and the 16 mm x 8 cm right iliac limb. The limb was post-dilated with a balloon catheter. Irregularity was seen at the distal end of the stent graft in the external iliac artery and it was treated with an uncovered 10 mm x 4 cm Absolute self-expandable stent (Guidant Corp., Santa Clara, California). To prevent distal embolization during manipulation of the occluded iliac artery, distal control of the common femoral artery was achieved though the cutdown. Immediately after, the patient recovered palpable pulses in the foot. Upon completion, angiographic injection revealed a type II endoleak from two lumbar arteries. Pressures recorded from the CardioMEMS sensor reported pressure waveforms of 156/100, compared to the pre-exclusion reading of 184/46. Improved flow in the lower extremities was revealed at 14-day follow-up, especially in the right leg, with a Doppler-readable signal in the posterior tibial and now-palpable dorsalis pedal. The patient’s claudication symptoms had improved.

In the three-month follow-up, the pressures from the CardioMEMS reported no pressure gradient, and no type 2 endoleaks were seen on follow-up CT scan. The patient’s blood pressure improved, but his creatinine had not changed.

Discussion

Endovascular aneurysm repair (EVAR) with aortouniiliac prostheses extends the morphologic range of aneurysms that can be treated, and is potentially a more rapid and simple operation than bifurcated endovascular repair.¹ However, this procedure is limited by the problems associated with a femorofemoral bypass graft, including localized and graft infection, and durability of the femoral-to-femoral bypass graft. Previous studies of femorofemoral bypass grafts were performed almost exclusively in patients with occlusive disease and not in relation to aneurysmal disease.^1,5 Cumulative patency rate for the femorofemoral bypass graft with EVAR patients has generally been good. Hinchliffe, et al. reported primary patency of 91% at 3 years and at the end of 5 years, 83%.¹ Lipsitz et al. reported 4-year life-table primary and secondary patency rates at 95% and 99%, respectively.⁵

For our patient with severe claudication of the right leg, the possibilities of a standard bifurcated stent graft offered much better results for increased flow than an aortomonoiliac endograft with femorofemoral bypass graft. Other complications associated with EVAR with aortouniiliac prostheses include wound complications, observed in 2–11% of patients with graft infections (2% of cases).^1–3 Acute thrombosis has been reported in 2% of cases.^4,5 We were fortunate in being able to cross the occluded iliac artery and deploy the stent graft, followed by a short iliac stent still within the external iliac. We were able to keep the femoral artery intact without having to place a stent near the joint space. If we were not able to cross the occlusion or if this patient’s occlusion had extended into the joint space, we would have had to alter our plans and perform with an aortomonoiliac endograft with a femorofemoral bypass graft. Careful attention must be made to avoid iliac occlusions that look as if they will tolerate recanalization and stent placement to the larger dimensions required by endovascular stent grafts. There is a real risk of iliac rupture in certain patients with small iliac diameters.

Conclusion

With the advent of new devices and techniques to recanalize chronic total occlusions, initial efforts should be made to re-open these vessels to allow for standard bifurcated EVAR. This case also showed the importance of stenting significant RAS prior to EVAR, in addition to the added benefit of monitoring endoleaks with the use of implantable pressure sensors.