EVAC versus REBOA in a Swine Model of Hemorrhage and Ischemia Reperfusion Injury.

BACKGROUND: Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is effective at limiting hemorrhage from non-compressible sources and restoring, yet causes progressive distal ischemia, supraphysiologic pressures and increased cardiac afterload. Endovascular Variable Aortic Control (EVAC) addresses these limitations, while still controlling hemorrhage. Previous work demonstrated improved outcomes following a 90-minute intervention period in an uncontrolled hemorrhage model. The present study compares automated EVAC to REBOA over an occlusion period reflective of contemporary REBOA usage.

METHODS: Following instrumentation, 12 Yorkshire-cross swine underwent controlled 25% hemorrhage, a 45-minute intervention period of EVAC or REBOA, and subsequent resuscitation with whole blood and critical care for the remainder of a six-hour experiment. Hemodynamics were acquired continuously and laboratory parameters were assessed at routine intervals. Tissue was collected for histopathologic analysis.

RESULTS: No differences were seen in baseline parameters. During intervention, EVAC resulted in more physiologic proximal pressure augmentation compared to REBOA (101 mmHg vs 129 mmHg 95CI 105-151, p=0.04). During critical care, EVAC animals required less than half the amount of crystalloid (3450 ml 95CI 1215-5684 vs 7400 ml 95CI 6148-8642, p<0.01) and vasopressors (21.5 ng/kg 95CI 7.5-35.5 vs 50.5 ng/kg 95CI 40.5-60.5, p=0.05) when compared to REBOA animals. EVAC resulted in lower peak and final lactate levels. EVAC animals had less aortic hyperemia from reperfusion with aortic flow rates closer to baseline (36 ml/kg/min 95CI 30-44 vs 51 mL/kg/min 95CI 41-61, p=0.01).

CONCLUSION: For short durations of therapy, EVAC produces superior hemodynamics and less ischemic insult than REBOA in this porcine controlled hemorrhage model, with improved outcomes during critical care. This study suggests EVAC is a viable strategy for in-hospital management of patients with hemorrhagic shock from non-compressible sources. Survival studies are needed to determine if these early differences persist over time.

LEVEL OF EVIDENCE: 1 STUDY TYPE: Translational Science.