Preoperative atrial fibrillation may not increase thromboembolic events in left ventricular assist device recipients on midterm follow-up

Abstract

Background: Atrial fibrillation (AF) is a well-established risk factor for thromboembolic (TE) complications. AF is frequently found in patients with advanced heart failure, including patients undergoing left ventricular assist device (LVAD) implantation. However, reports on whether preoperative AF increases the risk of TE events after LVAD implantation are scarce and limited to single-center or 2-center studies. We sought to evaluate the association of preoperative AF with TE events and patient survival using the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS).

Methods: A retrospective analysis of INTERMACS data of primary continuous-flow LVADs implanted between May 2012 and December 2013 was performed. Adult patients were dichotomized as having AF or no AF (NAF). TE events were defined as cerebrovascular accident, transient ischemic attack, hemolysis, arterial non-central nervous system embolism, or explant because of pump thrombosis. Kaplan-Meier analysis and multivariate Cox regression were performed for freedom from TE and patient survival.

Results: Of 3,909 patients identified during the study period, 838 (21.4%) had preoperative AF. Patients with AF were older, were likely to be male, and had more comorbidities (p < 0.01). In the AF group, 236 TE events occurred in 175 (20.9%) patients. In the NAF group, 900 TE events occurred in 691 (22.5%) patients. The TE event rate was not significantly different between the 2 groups (0.36 events/patient-year in AF group vs 0.37 events/patient-year in NAF group, p = 0.60). On univariate analysis, AF was not significantly associated with freedom from TE but was associated with decreased patient survival (log-rank test p = 0.03). On multivariate analysis, AF was not significantly associated with either TE (adjusted hazard ratio 0.95; 95% confidence interval, 0.80-1.13) or patient survival (adjusted hazard ratio 1.09; 95% confidence interval, 0.91-1.31).

Conclusions: Analysis of INTERMACS suggests that preoperative AF may not increase the risk of postoperative TE complications or patient mortality on midterm follow-up. Longer follow-up to confirm these findings is warranted.

Keywords: INTERMACS; LVAD; atrial fibrillation; patient survival; thromboembolic events.