Distal embolization after primary stent recanalization of an iliac artery occlusion

Clinical History

Complete occlusion of the right external iliac artery with femoral and popliteal disease and left-sided external iliac artery stenosis

Imaging Findings

Patient presented with stage III disease of her (rest pain) and stage II b (Fontaine) disease of her left leg. Angiography revealed eccentric stenosis of the left external iliac artery and complete occlusion of 8 cm length of the right external iliac artery (Fig. 1a). Additionally she had a severe stenosis of her right superficial femoral and her right popliteal artery (Fig. 1 b). It was decided to dilate and stent the left external iliac lesion and to recanalize the external iliac artery occlusion in the same session.

Discussion

The right external iliac artery was primarily passed via a cross over access from the left groin (Fig. 2 a) using a multipurpose catheter and a straight guidewire.A cross-over access was chosen because a left femoral puncture was already performed for treating the left ilaic artery.It was decided to test whether recanalization of the occlusion would possible in an antegrade fashion whih represents the access of choice of some authors.In case of failure, aretrograde passage would have been scheduled for another session. 5000 IU of heparine wer administered. After reaching the patent lumen of the distal external iliac artery, a right common femoral puncture and insertion of an 8 F sheath was performed and the guidewire was snared by use of a 10 mm gooseneck snare (Microvena distributed by Bard Inc.) within the patent segment of the common femoral artery. The occlusion was then passed by a 5 F multipurpose catheter and an 8 mm 8 cm long self-expanding nitinol stent (ZA stent, Cook Inc.) was placed into the occlusion without predilation. It turned out that the stent was a little too short to cover the lesion completely. Thus a dilation of the stent by use of a 6 mm 4 cm long balloon catheter was performed to allow safe placement of a second stent . Then, a second stent of 3 cm length was inserted. Full patency was restored (Fig. 2b). Final angiogram showed , however, distal embolization of occluding material that embolized into the distal popliteal artery (Fig. 3 a). Thus, an additional antegrade puncture of the right common femoral artery was performed and an 8 F sheath with a removable hub was inserted. An 8 F aspiration catheter was guided over a 0.035 in coated guidewire into the popliteal artery but was too large to pass the preexisting popliteal stenosis. Thus, a 6 F aspiration catheter was guided into the popliteal artery and aspiration was successful to remove all occluding material from the distal popliteal artery demasking the underlying stenosis (Fig. 3 b) which was subsequently dilated (Fig. 3 c) as well as the more proximal femoral lesion.Dilation of the femoral stenosis was performed after thrombosuction in order to avoid repeat passage of the aspiration catheter through a dilated vascular segment which might risk dissection. A residual stenosis remained in the popliteal artery but further dilation was avoided not to risk additional problems such as dissection. All sheaths were removed and prolonged manual compression of all puncture sides was performed. The next day, a small pseudoaneurysm of the right groin was detected that was successfully closed by ultrasound-guided compression. Embolization of occluding material is one of the major complications occuring with percutaneous management of iliac artery occlusions and occurs in 3 to 5 %. It may be avoided by complete primary stenting. Anyhow, all other manipulations around the occlusion may cause embolization but balloon dilation without a stent and dilation of the stent itself are the most risky steps concerning embolization. Due to the length of the stent chosen, the lesion was not completely covered in afirst attempt which required additional manipulations. This is probably the cause for embolization in that particular case. If embolization happens, four options might be feasible: In case of minor embolus obstructing small side branches , prolonged heparinization can be tried but should be checked by angiography. In case of major obstruction of the main arteries, surgical embolectomy, thrombolysis or - as it was performed in that case - aspiration embolectomy may be performed. Aspiration embolectomy is considered by us as a straight forward technique, easy to use offering a rapid success in most instances and is recommended as the method of choice in those cases.

Differential Diagnosis List

Final Diagnosis

Stenting of the occluded segment and aspiration embolectomy of the right popliteal artery

URL:	https://eurorad.org/case/623
DOI:	10.1594/EURORAD/CASE.623
ISSN:	1563-4086