Transvenous Pacing Leads and Systemic Thromboemboli in Patients With Intracardiac Shunts

Abstract

Background— The risk of systemic thromboemboli associated with transvenous leads in the presence of an intracardiac shunt is currently unknown. Methods and Results— To define this risk, we conducted a multicenter, retrospective cohort study of 202 patients with intracardiac shunts: Sixty-four had transvenous leads (group 1), 56 had epicardial leads (group 2), and 82 had right-to-left shunts but no pacemaker or implantable cardioverter defibrillator leads (group 3). Patient-years were accrued until the occurrence of systemic thromboemboli or study termination. Censoring occurred in the event of complete shunt closure, death, or loss to follow-up. Mean ages for groups 1, 2, and 3 were 33.9±18.0, 22.2±12.6, and 22.9±15.0 years, respectively. Respective oxygen saturations were 91.2±9.1%, 88.1±8.1%, and 79.7±6.7%. During respective median follow-ups of 7.3, 9.3, and 17.0 years, 24 patients had at least 1 systemic thromboembolus: 10 (15.6%), 5 (8.9%), and 9 (11.0%) in groups 1, 2, and 3, respectively. Univariate risk factors were older age (hazard ratio [HR], 1.05; P =0.0001), ongoing phlebotomy (HR, 3.1; P =0.0415), and an transvenous lead (HR, 2.4; P =0.0421). In multivariate, stepwise regression analyses, transvenous leads remained an independent predictor of systemic thromboemboli (HR, 2.6; P =0.0265). In patients with transvenous leads, independent risk factors were older age (HR, 1.05; P =0.0080), atrial fibrillation or flutter (HR, 6.7; P =0.0214), and ongoing phlebotomy (HR, 14.4; P =0.0349). Having had aspirin or warfarin prescribed was not protective. Epicardial leads were, however, associated with higher atrial ( P =0.0407) and ventricular ( P =0.0270) thresholds and shorter generator longevity (HR, 1.9; P =0.0176). Conclusions— Transvenous leads incur a >2-fold increased risk of systemic thromboemboli in patients with intracardiac shunts.