330 - Intravascular Ultrasound-Guided Transcaval Cisterna Chyli Access for Lymphatic Intervention: A Proof-of-Concept Study in a Porcine Model

Purpose: Lymphatic interventions are an emerging frontier for Interventional Radiology. However, obtaining central lymphatic access can be difficult, time-consuming and risks injury to critical structures. We hypothesize that intravascular ultrasound (IVUS)-guided transcaval central lymphatic cannulation is technically feasible, with the potential to reduce procedure time and associated risk.

Materials and Methods: Four female swine underwent transcaval central lymphatic cannulation. Animals were fed a high-fat diet preceding non-survival experimentation. We utilized a side-firing phased-array sectoral IVUS catheter (ViewFlex Xtra ICE; St. Jude, Saint Paul, MN) to visualize and perform direct lymphatic puncture using a 21-gauge echogenic tip needle, inserted through a transjugular intrahepatic portosystemic shunt kit deployed in the common femoral vein. The first cohort of two animals underwent nodal lymphangiography for fluoroscopic delineation of the lymphatic system followed by IVUS-guided central lymphatic access. The second cohort began with attempted de novo IVUS-guided access, though nodal lymphangiography was performed if unsuccessful. After cannulation, thoracic duct embolization (TDE) was performed using coils and/or glue.

Results: The TD was successfully cannulated via an IVUS-guided transcaval approach in all four animals. The first two animals demonstrated that the most capacious segments of the cisterna chyli was often too far from the cava for direct access, requiring access of the central lymphatics in close proximity to the inferior vena cava. In the second cohort, 1 (of 2) attempts to access the central lymphatics de novo was successful, which was achieved at a level similar to the two animals from cohort one. In the remaining experiment de novo access failed; subsequent nodal lymphangiography demonstrated variant lymphatic anatomy with a diminutive CC; IVUS-guided lymphatic cannulation was achieved in this case after nodal lymphangiography. At the conclusion of all experiments, TDE was performed successfully.

Conclusion: These data demonstrate that IVUS-guided central lymphatic access is technically feasible and provides adequate stability to perform TDE, while highlighting that de novo success is dependent upon lymphatic anatomy. This approach has the potential to reduce the time required to obtain central lymphatic access and associated risks.