1 - RCA proximal

The proximal right coronary artery (Proximal RCA - R1) is the initial segment of the right coronary artery (RCA) that extends from its origin at the right coronary sinus of the aorta to the origin of the first major branch, often the right ventricular (RVB; AM1) marginal branch.

In clinical and interventional cardiology literature, lesions are considered "proximal" if they are located before the takeoff of the last RV marginal artery greater than 1 mm in diameter. This segment includes the RCA ostium and the portion of the vessel that gives rise to early branches such as the conus branch, the sinoatrial nodal artery, and the proximal RV branches.