Thrombotic and Embolic Complications Associated With Atrial Arrhythmia After Fontan Operation: Role of Prophylactic Therapy

Background There are limited data about the risk of thrombotic and embolic complication (TEC) in adults with atrial arrhythmia after Fontan operation. Objectives This study sought to determine the risk of TEC in this population and the role of anticoagulation therapy in TEC prevention. Methods This was a retrospective review of adults with atrial arrhythmia after Fontan operation who were evaluated at the Mayo Clinic between 1994 to 2014. TEC was classified into 2 groups: systemic TEC, defined as intracardiac thrombus, ischemic stroke, or systemic arterial embolus; and nonsystemic TEC, defined as Fontan conduit/right atrial thrombus or pulmonary embolus. Patients were divided into 3 groups: anticoagulation, antiplatelet, and no therapy cohorts. Results We followed 278 patients, mean age 31 ± 9 years, for 88 ± 14 months (1,464 patient-years). Patient groups included antiplatelet (n = 181), anticoagulation (n = 91), and no therapy (n = 6). There were 97 TEC in 81 patients (29%); 32 were systemic, yielding an event rate of 2.1 systemic TEC per 100 patient-years, and 65 were nonsystemic TEC, yielding an event rate of 4.4 nonsystemic TEC per 100 patient-years. Prevalence of TEC was 18% and 55% at 5 and 10 years, respectively. Atriopulmonary connection was a risk factor for TEC (hazard ratio: 2.31; 95% confidence interval: 1.61 to 4.64), and TEC were associated with higher risk of death and hospitalization (p < 0.0001). Anticoagulation was protective against TEC and resulted in a reduction of TEC risk by 2.5 TEC per 100 patient-years. Anticoagulation was also associated with lower risk of death and hospitalization (p = 0.02). Bleeding complications occurred in 21 (7%) patients and were similar in all groups. Conclusions Anticoagulation was associated with lower TEC rate and lower risk of death and hospitalization, without a significant increase in bleeding risk. Perhaps anticoagulation should be the preferred preventive strategy.