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.