Percutaneous Coronary Intervention (PCI) typically begins with needle access to an artery in the arm or leg under local anesthesia. After arterial access is achieved, a thin sheath is inserted to facilitate and maintain the procedure. Through this sheath, very fine catheters (usually 2-3 mm in diameter) are advanced to reach the ostia of the coronary arteries that supply the heart, where they branch off the aorta. Subsequently, a contrast agent visible under X-rays is injected through these catheters to visualize the vessels (angiography). This imaging precisely determines characteristics such as the location, degree, and length of any narrowing or blockage. Following this, a balloon or a stent pre-mounted on a balloon is advanced over guide wires to the site of the narrowing or blockage. Under fluoroscopic guidance, the stent balloon is inflated, deploying the stent against the vessel wall at high pressure. This procedure opens the blocked or narrowed vessel, restoring blood flow.