No abstract

Objective Conventional epicardial excision is believed to be the most effective method of surgically obliterating the left atrial appendage (LAA), although incomplete resection and residual LAA volume may undermine its effectiveness. We sought to compare the impact of conventional epicardial excision with a novel LAA pericardial patch exclusion on residual LAA volume. Methods We performed LAA obliteration using pericardial patch exclusion, followed by conventional epicardial excision, in 27 cadaveric hearts. After each procedure, residual LAA volume was measured by two different techniques and compared with baseline volume. There was no difference in baseline LAA volume between each procedure. Results Procedural success was achieved in all hearts. Conventional epicardial excision left a residual LAA volume of 0.95 mL (24%), as compared with pericardial patch exclusion, which left a residual volume of 0.17 mL (4%, P = 0.0001). Further analysis of fixed and fresh hearts showed that reduction of LAA volume was more pronounced in the fresh hearts, suggesting effectiveness in live patients. Neither technique resulted in any significant change in the endocardial shape of the LAA orifice or injury to the circumflex artery. Conclusions Conventional epicardial excision of the LAA results in significantly more residual LAA volume, which may have important implications in persistent stroke risk. Pericardial patch exclusion seems to achieve near-total elimination of the LAA and may be a superior surgical option.

The coronary circumflex artery (CX) lies in the left atrioventricular groove, running intimately parallel to the mitral valve annulus. Thus, unintentional damage to the CX can occur via a fixation suture during mitral valve surgery, typically reported in hearts with a left dominant or co‐dominant circulation. This study aims to elucidate the anatomical relationship between the CX and annulus, and evaluate damage to the CX following three different mitral valve surgical repairs. It is predicted that left dominant or co‐dominant hearts should exhibit the closest anatomical relationship between the CX and annulus and experience a greater incidence of damage despite the chosen mitral valve surgery. Using fixed (n=18) and fresh‐frozen (n=9) cadaveric hearts, coronary circulation was dissected and dominance determined. After opening the left atrial wall, a clock face was overlaid on the mitral valve (12:00 position at the A2 leaflet midline) and the distance between the annulus and the CX was measured at each hour. The CX was closest to the annulus in fresh‐frozen, left dominant hearts. All left dominant and co‐dominant hearts had CXs that hugged the posterior length of the annulus, diving deep at 3:00 (before the posterior commissure), a finding previously unreported. Preliminary results from the ongoing surgical repairs advocate for cautionary suture placement in areas formerly considered to be at low risk for damage.

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.