Left Atrial Stiffness Increases after Trans-Catheter Atrial Septal Closure

Background: Transcatheter atrial septal closures for secundum atrial septal defects (ASD) have demonstrated favorable clinical outcomes. However, the impact of device implantation on the stiffness of the left atrium remains unclear. Method: Patients with secundum ASD undergoing transcatheter closure and follow-up right heart catheterization at six months were included. We investigated the relationship between post-procedural (E/e' ratio)/(LAs strain) ratio, an index of left atrial stiffness, and baseline characteristics, including echocardiographic and hemodynamic parameters. Results: Forty patients were included (median 69 (56, 75) years, 12 men, and pulmonary systemic flow ratio 2.27 (1.96, 2.86)). Trans-catheter ASD closure was successfully performed without any major complications, accompanying a significant reduction in right ventricular to left ventricular size ratio from 1.04 (0.87, 1.13) to 0.74 (0.66, 0.86) (p < 0.01). The (E/e' ratio)/(LAs strain) ratio was markedly elevated the day after the procedure and was further increased 6 months later (before: 0.25 (0.17, 0.34), 1 day later: 0.34 (0.27, 0.50), 6 months later: 0.43 (0.27, 0.76), p < 0.01). The groups with higher (E/e' ratio)/(LAs strain) ratios at 6 months had significantly more severe heart failure conditions including lower cardiac output and higher plasma B-type natriuretic peptides. Conclusions: Patients undergoing transcatheter ASD closure experienced improvement in hemodynamics and clinical symptoms but an elevation in left atrial stiffness post-procedure. The clinical ramifications of this finding, particularly during the longer-term observation period subsequent to ASD closure, warrant further investigation.