Extension of proximal deep vein thrombosis (DVT) into the inferior vena cava (IVC) complicates treatment with mechanical thrombectomy, as the presence of IVC thrombus increases embolization risks. In the case of a 39-year-old man with left-sided iliocaval DVT, the novel Protrieve sheath (Inari Medical, Irvine, California) was intraprocedurally placed in the IVC to ensure such complications would not outweigh the benefits of intervention. During successful thrombectomy, the sheath’s wall-apposing funnel trapped and removed procedural embolus from the IVC, with no complications occurring. Studies to determine whether the device can broadly improve the safety of complex DVT procedures are warranted.