Abstract
Introduction
Yttrium-90 (Y-90) radioembolization requires selective hepatic arterial delivery while minimizing nontarget embolization, particularly to the gastrointestinal tract, where inadvertent microsphere deposition can cause clinically significant radiation injury. Prophylactic coil embolization of extrahepatic branches can reduce this risk but is not always feasible when nontarget gastric vessels are too numerous, too small, or otherwise inaccessible to catheterization. Pressure-directed valve microcatheters may offer an alternative by altering local flow dynamics to eliminate reflux into nontarget branches while preserving delivery to the intended hepatic territory.
Case Info
A 77-year-old woman with biopsy-proven cecal adenocarcinoma and hepatic metastases was referred for liver-directed therapy after a left hepatic metastasis progressed despite systemic treatment. She had completed 12 cycles of folinic acid, fluorouracil, and oxaliplatin plus bevacizumab (FOLFOX–bevacizumab) and was subsequently receiving folinic acid, fluorouracil, and irinotecan plus bevacizumab (FOLFIRI–bevacizumab), which was held periprocedurally. Computed tomography (CT) demonstrated interval enlargement of the left hepatic lesion from 2.8 × 3.0 cm to 3.4 × 3.4 cm.
On mapping angiography, the tumor was supplied by the left hepatic artery, and numerous small branches supplied the adjacent gastric wall. Mapping with a conventional 2.8-French Progreat microcatheter (Terumo Medical Corporation, Somerset, NJ) demonstrated substantial gastric wall perfusion on cone-beam CT (CBCT). Because these branches were too numerous and small for practical coil embolization, mapping was repeated with a TriNav pressure-generating, one-way-valve, intermittently occlusive microcatheter (TriSalus Life Sciences, Westminster, CO). Repeat CBCT demonstrated elimination of visible gastric wall perfusion while tumor perfusion was maintained. Technetium-99m macroaggregated albumin (Tc-99m MAA) was then administered via the segment 2/3 hepatic artery through the TriNav catheter. Subsequent single-photon emission CT/CT (SPECT/CT) showed no extrahepatic intra-abdominal activity and a pulmonary shunt fraction of 3.3%.
Disc Clinical
Radioembolization of segments 2/3 was performed using Y-90 resin microspheres (SIR-Spheres; Sirtex Medical, Woburn, MA) delivered through the TriNav catheter. Intraprocedural CBCT demonstrated appropriate tumor blush without extrahepatic uptake, and the prescribed activity of 39.3 mCi was fully delivered. Post-treatment SPECT/CT showed intense localization of activity within the left hepatic mass without extrahepatic activity.
Shortly after the procedure, the patient developed abdominal discomfort, nausea, and vomiting and was admitted for overnight observation and supportive care with antiemetics, acid suppression, analgesia, and hydration. By the following morning she reported marked improvement, denied further nausea or vomiting, and was discharged with only mild residual left upper quadrant soreness. The rapid onset of symptoms may reflect a greater degree of embolization achieved with the TriNav catheter and a correspondingly earlier onset of post-embolization syndrome. These symptoms were readily managed, and use of the TriNav catheter enabled treatment of a lesion that would not otherwise have been feasible. This case illustrates how pressure-directed delivery can provide a technical solution when conventional coil protection is not feasible.
Conclusion
Pressure-directed valve microcatheter technology may facilitate selective radioembolization in patients with complex hepatogastric arterial anatomy when numerous small nontarget vessels cannot feasibly be coil embolized. In this case, the TriNav catheter eliminated visible gastric perfusion on mapping CBCT while preserving tumor targeting and enabling successful Y-90 delivery without post-treatment extrahepatic activity.