Incidence and Predictors of Stent Thrombosis Following Transcatheter Sinus Venosus Defect Closure

Following transcatheter closure (TCC) of sinus venosus defects (SVD), concerns exist about thrombus formation over the stents. Spatial and temporal resolution of Transesophageal echocardiography (TEE) is sensitive to detect even small thrombus. Following TCC of SVD between May 2014 to August 2025, all patients were imaged for thrombus after one-month and one-year. Thrombus were classified as major (> 5 mm thickness) or minor (layered ≤5 mm). Anatomical, procedural details and post-procedural thromboprophylaxis were compared between patients with and without thrombus detection. Among 153 patients following SVD closure, surveillance imaging involved TEE, computed tomography and magnetic resonance in 137, 7 and 2 cases respectively and transthoracic echocardiography alone in 7 patients. At a median follow-up period of one-month (range 0.5-16 months), thrombus was detected in eleven (7.2%) cases; major in three and minor layered in eight patients. All thrombi were asymptomatic, non-obstructive without any systemic or pulmonary thromboembolism. Bilateral superior venacava was associated with thrombus with an odds ratio of 4.5 (95% confidence interval 1.3-15.7; p = 0.01). Use of multiple overlapping stents (p = 0.02) and long procedural time (p = 0.04) were also identified as risk factors on univariate analysis. Occurrence of thrombus after dual antiplatelet therapy versus anticoagulation did not reach statistical significance (p-value 0.396). Artifacts in non-TEE imaging precluded high-quality pictures. Asymptomatic stent thrombosis is detected in 7.2% of patients after SVD closure during surveillance TEE. Alternative imaging might miss minor thrombus detection. Risk factors include bilateral SVC and use of multiple overlapping stents. Correct thromboprophylaxis following SVD closure needs prospective evaluation.