Effect of Oral Isosorbide Mononitrate Plus Amlodipine Antispasm Therapy on Outcomes of Radial Artery Grafts After CABG

The goal of this clinical trial is to to evaluate the effect of oral isosorbide mononitrate plus amlodipine antispasm therapy on outcomes of radial artery grafts in patients underwent primary isolated CABG. The main question it aims to answer is: Whether the oral isosorbide mononitrate plus amlodipine antispasm therapy could reduce the occlusion outcome of radial artery grafts after CABG . Researchers will compare isosorbide mononitrate plus amlodipine to none to see if isosorbide mononitrate plus amlodipine works. Participants will 1. Take oral isosorbide mononitrate (20-40mg daily) plus amlodipine (2.5-5mg daily) therapy for 24 weeks after CABG. 2. Clinical follow-up at Week 1, 4, 12, and 24 after CABG. 3. Protocol-driven CCTA at Week 24 after CABG.