Epicardial left atrial appendage closure-comparison of surgical techniques in an ex vivo model

Formation of clots in the left atrial appendage (LAA) may lead to embolism and consecutive cerebral stroke. This risk is reduced by closure and resection. To address the efficacy of surgical LAA closure, resilience to pneumatic pressure was studied. Different surgical techniques were compared in an experimental model.

From freshly slaughtered pigs cardiopulmonary preparations were taken. The left atrium was clamped airtight and the LAA was cannulated. Via a manually operated pump pressure was applied and a digital pressure gauge was connected. Four groups (each n=12) with different epicardial closures were studied: (I) purse string; (II) single layered continuous suture; (III) double layered suture; (IV) surgical stapler. A nonparametric test was used for group comparisons of mean burst pressures (mmHg). Statistical significance was defined at P<0.05.

Mean burst pressures in group 1 amounted to 97.1±13.0 mmHg, in group 2 to 105.5±13.3 mmHg, in group 3 to 124.6±14.2 mmHg and in group 4 to 136.6±12.5 mmHg. Excepting differences between groups 1 and 2 comparisons between groups were significantly different.

In an ex vivo model surgical staplers and double layered hand crafted sutures proved well suitable for closure of the LAA. They were significantly superior to single layered sutures in terms of resilience to pneumatic pressure. This may be relevant to durability and should be discussed with regard to clinical choice.