Abstract 4371922: Femoral-Femoral Crossover Shunting Enhances Limb Perfusion During VA-ECMO

Introduction: Acute limb ischemia (ALI) is a common and serious complication in patients undergoing femoral veno-arterial extracorporeal membrane oxygenation (VA-ECMO), largely due to compromised distal limb perfusion. This study evaluates the role of femoral-femoral crossover shunts in maintaining distal limb perfusion in patients on VA-ECMO. Hypothesis: Femoral-femoral crossover shunting during femoral VA-ECMO significantly increases distal limb perfusion and may reduce the incidence of ALI. Methods: We conducted a retrospective review of all patients who underwent femoral VA-ECMO at our tertiary care institution between December 2024 and May 2025. Patients were included if they received femoral-femoral crossover shunts and underwent lower extremity duplex ultrasound during ECMO. Collected variables included patient demographics, cannulation technique, shunt characteristics, and duplex ultrasound measurements—peak systolic velocity and volume flow—in the superficial femoral artery (SFA), popliteal artery (PA), and posterior/anterior tibial arteries (PT/AT). Flow velocity and volume were measured in the cannulated limb with the shunt on and off, as well as in the uncannulated limb. Descriptive statistics were used to analyze associations with distal perfusion parameters. Results: Thirteen patients underwent femoral VA-ECMO with distal reperfusion during this period. The mean age was 47 years, and 53% of patients were male. Three patients had complete duplex ultrasound data. Mean flow volumes were higher when the shunt was open: SFA flow volume increased by 218% (from 47.2 to 150.3 mL/min), PA by 161% (25.0 to 66.7 mL/min), and PT/AT by 27% (9.5 to 12.1 mL/min). In the cannulated limb, the shunt increased SFA peak systolic velocity by 38% (25.3 to 35.0 cm/s), PA velocity by 21% (25.3 to 30.7 cm/s), and PT/AT velocity by 19% (19.2 to 23.0 cm/s). In the uncannulated limb, mean SFA, PA, and PT/AT velocities were 66.3, 70.0, and 20.0 cm/s, respectively, with corresponding flow volumes of 142.3, 94.0, and 6.2 mL/min. None of the patients in this cohort developed clinical signs of acute limb ischemia. Conclusion: Femoral-femoral crossover shunting during femoral VA-ECMO appears to improve distal limb perfusion, with notable increases in both velocity and flow. These findings suggest that crossover shunting may serve as a practical adjunct to mitigate ischemic complications in patients undergoing femoral cannulation for ECMO support.