Y90-radioembolization via variant hepatic arteries: Is there a relevant risk for non-target embolization?

BACKGROUND The hepatic arterial anatomy is highly variable, with the two most common variants being a replaced right hepatic artery(RHA) originating from the superior mesenteric artery(SMA) and a left hepatic artery(LHA) originating from the left gastric artery(LGA). These anatomical variants could potentially increase the risk for non-target embolization during Y90-Radioembolization due to the close proximity between hepatic and enteric vessel branches.AIM To evaluate the safety of Yttrium-90radioembolization(90Y-RE) with resin microspheres in patients with a variant hepatic arterial anatomy.METHODS In this retrospective single-center observational study, 11 patients who underwent RE with 90Y-resin microspheres via a LHA originating from the LGA,and 13 patients via a RHA originating from the SMA were included. Patient and treatment data were reviewed regarding clinical and imaging evidence of nontarget embolization of 90Y-resin microspheres to the GI tract. Positioning of the tip of the microcatheter in relationship to the last hepatoenteric side branch was retrospectively analyzed using angiographic images, cone-beam CT and preinterventional CT-angiograms.RESULTS None of the 24 patients developed clinical symptoms indicating a potential nontarget embolization to the GI tract within the first month after 90Y-RE. On thepostinterventional 90Y-bremsstrahlung images and/or 90Y-positron emission tomographies, no evidence of extrahepatic 90Y-activity in the GI tract was noted in any of the patients. The mean distance between the tip of the microcatheter and the last enteric side branch during delivery of the 90Y microspheres was 3.2 cm(range: 1.9-5 cm) in patients with an aberrant LHA originating from a LGA. This was substantially shorter than the mean distance of 5.2 cm(range: 2.9-7.7 cm) in patients with an aberrant right hepatic originating from the SMA.CONCLUSION90Y-RE via aberrant hepatic arteries appears to be safe;at least with positioning of the microcatheter tip no less than 1.9 cm distal to the last hepatoenteric side branch vessel.