Impact of preoperative atrial fibrillation on thromboembolic events and pump thrombosis in long-term left ventricular assist device therapy.

Abstract

Pump thrombosis (PT) and thromboembolic events (TEs) remain major adverse events in left ventricular assist device (LVAD) therapy at an annual rate of 6-8% supported with the HeartWare HVAD and HeartMate II. PT and TEs are multifactorial events. Understanding the predisposing risk factors for PT and TE is paramount to define preventive strategies. Preoperative atrial fibrillation (AF) is considered a significant and potentially modifiable risk factor. This study investigates whether LVAD patients with AF exhibit a higher rate of PT and TE than those in sinus rhythm (SR). We evaluated medical records of consecutive patients who underwent implantation of the HeartMate II (n = 195; 25.4%) and HeartWare HVAD (n = 574; 74.6%) at our institution between 2006 and 2015. Only visually confirmed PT was included in the study. TE was defined as any peripheral embolism or cerebral embolism according to the INTERMACS definitions. SR was documented preoperatively in 211 patients (SR group) and AF in 558 patients (AF group). The median duration of support was 0.78 years in the AF group and 1.03 years in the SR group. The mean age was 60.27 years in the AF group and 52.04 years in the SR group. In the AF group, 83.0% of the patients were male, compared to 77.3% in the SR group. The cumulative incidence of PT in the SR group was 2.5% [95% confidence interval (CI) 0.3-4.7%] after 1 year and 5.7% (95% CI 2.2-9.2%) after 2 years, and in the AF group 4.9% (95% CI 3.0-6.7%) and 7.8% (95% CI 5.4-10.2%), respectively (P = 0.129). TEs were recorded in the SR group in 4.4% (95% CI 1.6-7.2%) after 1 year and in 6.3% (95% CI 2.8-9.8%) after 2 years, and occurred after a median support time of 214 days (range 120-768). In the AF group, the cumulative incidence was 8.4% (95% CI 6.0-10.7%) and 10.7% (95% CI 8.0-13.4%), respectively, after a median support time of 116 days (range 37-375), P-value = 0.163. In the multivariate analysis, event-free survival was not influenced by the preoperative SR [hazard ratio (HR) 0.86, 95% CI 0.68-1.1; P = 0.19]. Our study showed that the preoperative rhythm has no impact on survival, PT and TEs despite different preoperative risk factor profiles in the AF and SR group. Thus, the effect of a maze procedure, catheter ablation or left atrial appendage closure on PT and TE's for AF patients during LVAD implantation is questionable. However, to obtain a definitive answer, a prospective study would be of value.