A Technique for Limiting Y-90 Uptake in the Gallbladder

Prophylactic temporary occlusion of the cystic artery with a detachable coil during yttrium-90 (Y90) radioembolization seems to be a feasible, effective way to limit the uptake of Y90 in the gallbladder. Researchers reported their findings in CardioVascular and Interventional Radiology.

Radiation of nontarget internal organs during radioembolization can lead to a variety of complications that practitioners strive to prevent. Although prophylactic embolization of the cystic artery has been used to prevent nontarget infusion of Y90, it could lead to ischemic cholecystitis, and its effectiveness is difficult to assess as a result of the small number of cases of cholecystitis that require treatment.

In a retrospective study that took place from January 2012 to October 2016, Choi and colleagues examined whether prophylactic temporary occlusion of the cystic artery using a detachable coil is feasible and effective. Nine patients underwent temporary occlusion of the cystic artery during Y-90 radioembolization.

Before treatment, patients had planning angiography and C-arm CT imaging to determine if cystic artery occlusion was warranted for preventing nontarget embolization. The planning angiography guided deployment of a detachable coil into the cystic artery of the 9 patients included in the study. “In general, prophylactic occlusion was performed when the cystic artery arose from a more distal level (e.g., right anterior hepatic artery) than its usual origin and distal positioning of microcatheter tip was impossible,” the authors wrote. The proximal 1 cm of the coil was left inside the microcatheter to facilitate retrieval of the coil after radioembolization.

After attenuation of blood flow through the cystic artery was confirmed, a microcatheter was used to infuse Y90 microspheres proximal to the cystic artery (where 99mTc-MAA had previously been infused). The coil was retrieved after this infusion.

Following the procedure, the patients underwent hybrid PET/CT imaging, which was used to assess effectiveness. Wilcoxon's signed-rank test was used to determine the differences in the uptake of 99mTc-MAA and Y-90 microspheres in the gallbladder.

There were no clinical complications observed for 3 months after the procedure occurred, and results supported the feasibility of a detachable coil in all cases, the authors noted. In 8 of 9 patients, the distal cystic artery and gallbladder were partially identifiable on the angiograms performed after detachable coil placement. After coils were removed, they were fully restored in all cases.

The authors acknowledged the limitations of the study’s design and the need for larger studies with a comparative arm. They believe the procedure could be helpful in certain cases though. “This technique could be particularly useful when the cystic artery arises from a more distal level (e.g., right anterior hepatic artery) than its usual origin and 99mTc-MAA is highly accumulated on the pre- procedural SPECT/CT study,” they stated. “Our technique could also be applied to save the normal liver parenchyma by temporarily blocking the nontarget hepatic artery when tumors are located in the central portion of the liver.”

Reference

Choi JW, Yoo MY, Kim HC, Paeng JC, Kim YJ, Chung JW. Prophylactic temporary occlusion of the cystic artery using a fibered detachable coil during 90Y radioembolization. Cardiovasc Intervent Radiol. 2017; 40(10): 1624-1630.