Abstract No. 321 EE: Identification and Embolization of Vascular Loops Prior to Catheter-Directed Treatment of Primary and Secondary Hepatic Malignancies

Article Outline

• Purpose
• Materials & Methods
• Teaching Points
• Copyright

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Purpose 

Nontarget embolization during catheter-directed therapy of liver tumors can result in severe gastrointestinal (GI) toxicity. We describe imaging findings and management strategies of unusual anomalous arterial connections or “vascular loops” prior to transarterial therapy of hepatic malignancies.

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Materials & Methods 

Between January 2004 and April 2008, out of approximately 1200 embolization procedures, we encountered 7 patients with vascular loops prior to transarterial chemoembolization (TACE) (n=4) and immunoembolization (IE) (n=3) in 4 patients with metastatic uveal melanoma and 3 patients with hepatocellular carcinoma. Diagnostic arteriography showed retrograde flow through portions of each vascular loop, producing an unacceptable risk of nontarget embolization. Vascular loops illustrated include: an accessory right hepatic artery (HA) arising from the superior mesenteric artery (SMA), anastomosing with the right HA arising from the normal proper HA (n=4); a medial segment left HA arising from the proper HA originating from the SMA, anastomosing with a medial segment left HA arising from the celiac artery (n=1); an accessory right HA arising from the common HA, anastomosing with the main right HA (n=1); and a right HA branch arising from a replaced common HA, anatomosing with a left lateral segment HA arising from the left gastric artery (n=1). Coil embolization was performed of 3 accessory right HAs, 1 main right HA, 1 distal common HA/proximal gastroduodenal artery, and 1 right HA branch prior to TACE and IE. Subselective catheterization distal to a vascular loop was possible in 1 patient, obviating the need for embolization. Nontarget coil embolization of a splenic artery branch and an ileocolic artery occurred in 2 patients; the latter was retrieved. Neither complication caused clinical sequelae. TACE and IE were possible in all patients and performed without additional complications of nontarget embolization.

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Teaching Points 

Failure to identify and treat vascular loops will result in nontarget embolization of therapeutic agents into the GI tract. In most cases, coil embolization of vascular loops prior to catheter-directed treatment of liver tumors is essential to limit GI toxicity.