Characterization of Postoperative Atrial Fibrillation After Continuous Flow Left Ventricular Assist Device Implant as Destination Therapy
Nadia H. Bakir, Meghan O. Kelly, Joel D. Schilling, Gregory A. Ewald, Samuel C. Perez, Akinobu Itoh, Marc R. Moon, Spencer J. Melby, Ralph J. Damiano, Kunal D. Kotkar, Muhammad F. Masood
Washington University School of Medicine, St. Louis, MO, USA
Background: Continuous flow left ventricular assist devices (CF-LVADs) have been increasingly used as destination therapy (DT). While modern devices have been associated with decreased stroke risk, postoperative atrial fibrillation (POAF) remains a common complication following cardiac surgery and is associated with numerous complications. The purpose of this study was to characterize POAF in relation to stroke burden in a modern institutional cohort of CF-LVAD patients with DT indication.
Methods: Patients implanted with CF-LVAD as DT at our center from 2010-2020 were retrospectively reviewed using our institutional STS and INTERMACS databases. Stroke was defined as any confirmed neurological deficit caused by abrupt disruption in cerebral blood flow that did not resolve within 24 hours and was confirmed by imaging. A competing risks model to account for death during follow-up was applied to evaluate stroke outcomes. Fine-Gray regression was used to evaluate thirty-five covariates.
Results: Patients implanted with CF-LVAD (n=304) were classified by HeartMate II (n=190), HeartMate III (n=72), and HVAD (n=42) device type. Preoperatively, 45% (138/304) of patients had a history of AF. Following CF-LVAD implant, 37% (111/304) developed POAF. Estimated stroke incidence was 15%, 24%, and 26% at 1, 3, and 5 years, respectively. Stroke was categorized as either hemorrhagic (39/70;56%) or embolic (31/70;44%). On multivariable Fine-Gray regression, HeartMate III (Subdistribution Hazard Ratio (SHR) 0.39 (0.18,0.86), P=0.020) and amiodarone were associated with lower stroke risk (SHR 0.52 (0.30,0.91), P=0.021); POAF was associated with increased stroke risk (SHR 1.65 (1.01,2.71), P=0.047), while preoperative AF was not significant (P=0.25). POAF resolution within 90 days occurred in 90% (100/111) of patients. Of the patients whose condition resolved within 90 days, 84% (84/100) were treated with amiodarone and 17% (17/100) with cardioversion prior to resolution.
Conclusion: POAF following CF-LVAD implant was associated with late stroke, while amiodarone at discharge appeared to have a protective effect. The use of HeartMate III was associated with decreased stroke rates, but risk remained high in patients who developed POAF. Further investigation is warranted on protective strategies and therapeutic use of amiodarone for POAF after CF-LVAD implantation. 
LEGEND: Competing risks of death and stroke following CF-LVAD implantation for destination therapy.