Pediatric/Adult Congenital Heart Disease -> Pediatric Cardiology D-AB15 - Pacing in Patients with Congenital Heart Disease (ID 44) Abstract

D-AB15-02 - Clot Burden In Fontan Patients With And Without Transvenous Pacemakers (ID 1409)


Background: Permanent pacemaker (PPM) implantation is the most frequent surgical re-intervention in Fontan patients. Emerging techniques have made transvenous (TV) PPM implantation an available option. However, the thrombogenic potential of leads within the Fontan baffle remains unknown.
Objective: To compare the clot burden in Fontan patients with a TV PPM to those without a TV PPM.
Methods: This was a retrospective cohort study of all TV PPM implantations in Fontan patients at our institution (January 2000-December 2018). We performed frequency matching on Fontan type and age group (10-19 yrs, 20-39 yrs, ≥40 yrs) in a 2:1 ratio. Primary outcome was identification of intracardiac clot, pulmonary embolism, or embolic stroke.
Results: Of 1,920 Fontan patients, 58 patients with a median age of 23 yrs (IQR 25-75 14-33) at time of TV PPM implantation and 116 matched subjects formed our cohort. The most common underlying heart defect was tricuspid atresia (45%) followed by double inlet left ventricle (17%). The type of Fontan performed in our cohort was as follows: atriopulmonary (47%), lateral tunnel (41%), RA-RV conduit (9%), and extracardiac (3%). The vast majority had a single transvenous atrial lead (86%) with the leading indication being sinus node dysfunction (76%). The cumulative incidence of clot in case subjects was similar to those without a TV PPM (10.3% vs. 14.7%, p=0.49). Variables associated with clot formation included: RA-PA Fontan type (p=0.011), atrial tachyarrhythmia (p=0.038), and older age at Fontan (p=0.042). Age, gender, ventricular morphology, EP ablation and any anticoagulation including warfarin/apixaban/rivaroxaban did not differ significantly between the two groups.
Conclusion: In a large cohort of Fontan patients matched for age and Fontan type, patients with TV PPM had a similar incidence of clot compared with patients without TV PPM. RA-PA Fontans and history of atrial tachyarrhythmia are risk factors for clot. Lateral tunnel and extracardiac Fontan patients without atrial arrhythmia may not require additional anticoagulation beyond that recommended for their Fontan management.