Abstract 315: Endovascular Aortic Occlusion Preferentially Improves Hemodynamics and Return of Spontaneous Circulation After Longer Periods of Cardiopulmonary Resuscitation: A Translational Study in Swine

Abstract

Introduction: Non-traumatic cardiac arrest (NTCA) is associated with low survival and substantial societal cost. Standard-of-care treatments, such as cardiopulmonary resuscitation (CPR) and advanced cardiac life support (ACLS), have limitations in restoring cardiac function and improving outcomes. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as an adjunct to CPR for NTCA. However, the optimal patient population that will benefit most from REBOA remains uncertain. Goals: This translational study investigated the impact of varying low-flow duration (15- vs 30-mins) on REBOA's hemodynamic performance and ability to achieve return of spontaneous circulation (ROSC) in a swine model of NTCA. Methods: Thirty-two swine were anesthetized and placed into ventricular fibrillation. All animals received a 4-min “no-flow” period before mechanical CPR was initiated. Animals were randomized into four groups to receive: 1) 15- vs 30-minutes of CPR; 2) REBOA vs. no-REBOA (control). After completion of the 15- or 30-minute low-flow period, ACLS was initiated and REBOA was fully-inflated in experimental animals. Results: There were no differences in demographics or hemodynamics at baseline (T = -10-mins) or at randomization (T = +10-mins). In the 15-mins groups, there were no differences in the rates of ROSC between REBOA (4 / 8, 50%) and control (4 / 8, 50%; p = 0.99). However, in the 30-min group the REBOA animals had a significantly higher rate of ROSC (6 / 8, 75%) compared to control (1 / 8, 12.5%; p = 0.04). In the 7-mins (T = 34 - 41 mins) after REBOA deployment in the 30-min animals there was a statistically significant difference in diastolic blood pressure (repeated measures ANOVA; p = 0.027). Importantly, 5 / 6 (83%) animals that received ROSC in the 30-min group with REBOA re-arrested at least once with 3 / 6 (50%) maintaining ROSC until study completion. Conclusion: In our swine model of NTCA, REBOA preferentially improved hemodynamics and ROSC after a 30-mins period of low-flow CPR, compared to 15-mins of low-flow CPR. REBOA may be a viable strategy to improve ROSC after prolonged downtime. More hemodynamic support will be required to maintain ROSC. This has implications for patient selection in upcoming human trials of REBOA in NTCA.