Durable Left-Ventricular Assist Device Inflow Thrombosis Following External Outflow Graft Obstruction

Background: External outflow graft obstruction (EOGO) is an emerging complication due to improved pump durability. We experienced a rare sequence of complications, inflow thrombus formation following EOGO with reduced left-ventricular assist device flow. Case Summary: A 41-year-old man, 2 years post HeartMate 3 (HM3) implantation, presented with low-flow from EOGO. Outflow graft stenting resulted in improvement but returned 1 month later with persistent low flow. Pump thrombosis was excluded. Flow had minimal response to RPM increase. Outflow graft was widely patent. Inflow obstruction was suspected, and HM3-to-HM3 exchange revealed extensive thrombus formation within the inflow cannula. Left-ventricular assist device flow returned to normal. Postoperative recovery was uneventful. Discussion: The cause of this inflow thrombus formation, an extremely rare complication, was suspected to be from EOGO low flow. Take-Home Messages: Inflow thrombosis should be included in the differential diagnosis with low flow. EOGO low flow could cause secondary inflow thrombosis.