Evaluation of Two Methods of Left Atrial Appendage (LAA) Closure and its Proximity to the Circumflex Artery

Abstract

Patients with atrial fibrillation have an increased risk of stroke due to thrombi originating in the left atrial appendage (LAA). The standard for LAA closure is epicardial excision, which can leave a residual LAA volume thereby undermining its effectiveness. Moreover, the circumflex artery runs close to the base of the LAA, making it susceptible to damage during surgery. This study aims to compare residual volume in the LAA after epicardial excision to that left by a novel pericardial patch exclusion technique, and to track the circumflex artery around the base of the LAA. It is hypothesized that the exclusion will leave less volume than excision. Male and female fixed (n=18) and fresh (n=9) cadaveric hearts underwent both methods of obliteration. After each procedure, the residual volume of the LAA was measured by water and agarose gel. The proximity of the circumflex artery was plotted using a clock‐face. The excision method left a mean residual volume of 0.95 mL (24% of the original), whereas the pericardial patch exclusion left 0.17 mL (4% of original) (p<0.0002). The circumflex artery was closest to the LAA at the 4 o'clock position. The results suggest i) that the novel pericardial patch exclusion technique is more effective than excision, and ii) that surgeons should be most aware of the circumflex artery at the 4 o'clock position around the LAA base. This may lead to changes in the way closure of the LAA is performed.