Identifying the optimal site for intentional right atrial appendage perforation for pericardial CO₂ insufflation: A...

Trans-right atrial appendage (RAA) pericardial carbon dioxide (CO₂) insufflation has been shown to be feasible and safe in small case series. The optimal RAA perforation site remains undefined.

This study aimed to identify the RAA region offering the most favorable spatial relationships for safe trans-RAA pericardial access using contrast-enhanced cardiac computed tomography.

50 consecutive patients (24 men; 57 ± 12 years) undergoing contrast-enhanced cardiac computed tomography were studied. The RAA was analyzed in 3 equidistant axial planes (basal, mid, and high) oriented perpendicular to a vertical line through the RAA apex. Each plane was divided into 6 segments-septal and lateral, each subdivided into posterior, mid, and anterior regions. Distances to adjacent epicardial structures were measured for each segment.

Lateral RAA segments directly contacted the parietal pericardium (0 mm [interquartile range 0-0 mm]). Posterior and midseptal segments closely approximated the aorta (3.8 mm [2.3-8.2 mm]). Only the septal anterior region bordered a visible pericardial space between the parietal pericardium, aorta, right coronary artery (RCA), and right ventricular outflow tract. The greatest separations occurred at the high septal anterior plane (right ventricular outflow tract 12.4 mm; aorta 6.3 mm; parietal pericardium 9.8 mm; RCA 13.4 mm). In 4 patients, RCA branches coursed within 5 mm of the RAA. Results were consistent in an additional validation cohort of 8 patients undergoing trans-RAA carbon dioxide insufflation and 2 patients with aortic dilation.

The high septal anterior RAA offers the most favorable anatomic clearance for transatrial pericardial access, whereas the lateral and remaining septal walls lie in close proximity to the parietal pericardium and aorta.