This prospective observational cohort study aims to investigate the prevalence and clinical significance of head and neck arterial stenosis in patients with coronary artery disease (CAD) undergoing or scheduled for percutaneous coronary intervention (PCI). Using Doppler ultrasound as the primary screening tool, the study will assess the degree of stenosis and evaluate the impact of different combined treatment strategies on patient outcomes. The research will provide real-world evidence to optimize integrated care approaches for patients with comorbid cardiovascular and cerebrovascular diseases.