Pneumatic Burst Pressures After Inverted Closure of the Left Atrial Appendage: An Ex Vivo Model

Abstract

The left atrial (LA) appendage (LAA) is the main source of thromboembolism in atrial fibrillation. This study addressed initial pressure resistance of surgical LAA closures. In an experimental model, pneumatic pressure resistances of different surgical closure techniques were examined, and variations in technique and access were studied. In preparations of the LA from freshly slaughtered pigs, pneumatic pressure was applied to the LAA. Burst pressures (mbar) of various closure techniques (n= 12 specimens per group) were measured: (1) epicardial double-layer suture, (2) epicardial stapler closure (staple height 2 mm), (3) epicardial stapler closure (staple height 4, 4.5, and 5 mm), (4) endocardial inverse double-layer suture, (5) endocardial inverse stapler seam (staple height 2 mm), and (6) endocardial inverse stapler seam (staple height 4, 4.5, and 5 mm). The mean burst pressure in group 1 was 175.5 ± 19.35 mbar. There was no significant difference compared with group 2 (174.5 ± 28.45 mbar) or group 3 (176 ± 27.69 mbar). Group 4 scored significantly higher than all other groups (198.9 ± 18.35 mbar). Burst pressures in group 5 (136.2 ± 16.68 mbar) were significantly lower than in group 4 and in group 6 (165.1 ± 21.94 mbar), but the differences between groups 5 and 6 were also significant. In an exvivo model, double-layer suturing of the inverted LAA from an internal LA access led to higher burst pressures compared with epicardial suturing and with both endocardial and epicardial stapled closures.