右房耳穿孔による心膜CO₂送気のための最適な部位特定：心臓CTによる解剖学的評価

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

To identify the RAA region offering the most favorable spatial relationships for safe trans-RAA pericardial access using contrast-enhanced cardiac computed tomography (CT).

Fifty consecutive patients (28 men; 57 ± 12 years) undergoing contrast-enhanced cardiac CT were studied. The RAA was analyzed in three equidistant axial planes (basal, mid, 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 [IQR 0-0 mm]). Posterior and mid-septal 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, RCA, and RVOT. The greatest separations occurred at the high septal anterior plane (RVOT 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 CO₂ insufflation and 2 patients with aortic dilatation.

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