Cath Lab Digest

Introduction
Iliac stenting for occlusive atherosclerotic disease is an accepted therapeutic modality. Completely occluded iliac arteries can be wire recanalized with a high degree of success¹ and acceptable long-term results. The technical aspects of crossing an iliac chronic total occlusion (CTO) can however remain challenging. We describe a novel technical modality to facilitate wire recanalization in difficult cases.

Case Report
A 60-year-old Hispanic male presented with right-sided buttock and thigh claudication after walking one block. Risk factors for peripheral vascular disease included hypertension, hyperlipidemia, and non-insulin dependent diabetes. He also had a past history of smoking. He reported erectile dysfunction. He had no renal insufficiency with a creatinine of 0.8 mg/dL. Physical examination revealed non-palpable right femoral and distal pulses. Left side pulses were normal. No iliac bruits were audible. Ankle brachial pressure indices were 0.51 and 0.67, and on the right and left, respectively. A magnetic resonance angiogram was obtained (Figure 1) revealing a right common iliac occlusion and mild left common iliac stenosis. The patient felt limited by this problem and the decision was made to intervene.

Percutaneous retrograde access was achieved in the right common femoral artery and the patient was anticoagulated with intravenous heparin. A sheath angiogram confirmed patency of the external and internal iliac arteries as well as the distal 1 cm of the right common iliac artery.

A soft 0.035" Glidewire (Terumo, Tokyo, Japan) could not be advanced past the cap of the occlusion, and a straight, stiff 0.035" Glidewire, supported by an angled 5-Fr diagnostic catheter, was substituted. Attempts to keep the wire intraluminal were not successful and a subintimal plane was created cephalad to the lateral aortic wall. The true lumen could not be reentered.

Hence, access was achieved in the left common femoral artery with a 6-Fr sheath, and a stiff 0.035" Glidewire supported by a Sos 5-Fr catheter was used to break the cap of the occlusion in the proximal right common iliac artery stump using a contralateral approach. This resulted in subintimal wire entry and advancement. Despite the use of a variety of angled and straight wires, as well as a variety of catheters including Cobra tips and Spectranetics QuickCross catheters, the distal true lumen of the right iliac artery could not be entered.

At this time, the decision was made to try to snare the subintimally located guidewire. Hence, using the right femoral approach, the catheter of the Amplatz snare (Microvena, White Bear Lake, Minnesota) was advanced partially into the occluded common iliac artery in a retrograde direction, and a 25 mm Amplatz gooseneck snare advanced into the subintimal space. The snare was used to dissect the plane widely and grab the wire being advanced from the left groin in an up-and-over fashion, achieving “flossing-technique”.² Once this was achieved, kissing wires could be placed following catheter exchange over the floss wire. The right iliac artery was then debulked using the Spectranetics laser (Spectranetics, Colorado Springs, Colorado) with 2 passes of a 1.4 mm probe, followed by deployment of balloon-expendable kissing stents. The patient regained palpable femoral and distal right side pulses. No closure devices were used. He was seen in follow up with improved walking distance, but erectile dysfunction was persistent.

Discussion
When trying to cross an iliac CTO, two major options exist: intraluminal or subintimal wire passage. The long-term results do not differ much and either method is acceptable.³ Often shorter occlusions can be crossed intraluminally whereas more chronic and longer occlusions require subintimal wire passage. Either approach can be done in a retrograde or up-and-over antegrade fashion. Often a combination is needed.⁴ When trying to penetrate the cap of an occlusive plaque, blunt microdissection devices such as the Frontrunner (Johnson & Johnson, New Brunswick, New Jersey) are available.⁵ It is not clear whether such devices promote staying in the true lumen or lead to a subintimal plane. A radiofrequency-associated device (SafeCross) designed to keep the wire in the true lumen was marketed for a while but is no longer available for use.