Fatraya, Q. J.; Safri , Z.; Lubis , A. C. The Relationship Between Elevated Systemic Immune-Inflammatory Index (SII) and the Severity of Coronary Lesions in Chronic Coronary Syndrome (CCS) Patients Undergoing Coronary Angiography at Haji Adam Malik Hospital Medan. JSocMed 2025, 4, 175-182.