A PRospective Observational Study on the Relationship BEtween Coronary Angiography Findings and Fractional Flow Reserve After Balloon Angioplasty: PROBE-FFR
The goal of this prospective observational study is to learn about in patients who need percutaneous coronary intervention for coronary artery disease. The main questions it aims to answer are: * Fractional flow reserve according to coronary angiography findings after coronary artery balloon angioplasty * Differences in fractional blood flow reserve before and after lesions between coronary balloon angioplasty using a scoring balloon and a regular balloon Participants will voluntarily consent to the study after being fully informed about the study and given ample opportunity to ask questions.
• Patients with clinically stable coronary artery disease
• Patients undergoing balloon angioplasty as an interventional procedure (FFR-guided PCI) using coronary artery fractional blood flow reserve for de novo lesions with a standard vessel diameter of 2.25 mm or more under percutaneous coronary angiography (hereafter referred to as coronary angiography)
⁃ (Note) If there are other lesions in the proximal area and the FFR of the distal lesion is collected, it is included in the selection target regardless of whether or not the proximal lesion was operated on.