Multicenter Study on Early Arterial Changes in Prediabetic Patients Evaluated by Ultra-High-Frequency Ultrasound

Prediabetic Patients Inclusion Criteria: * Impaired fasting glucose (venous plasma glucose ≥6.1 mmol/L, \<7.0 mmol/L, and \<7.8 mmol/L 2 hours after glucose loading); and/or Impaired glucose tolerance (venous plasma glucose \<7.0 mmol/L, and ≥7.8 mmol/L, \<11.1 mmol/L 2 hours after glucose loading). * Age ≥ 18 years old; * Normal blood pressure (139-90/89-60 mmHg); * Body mass index (BMI) \< 30 kg/m²; * Normal results in routine blood tests, fasting blood glucose, lipid profile, liver and kidney function tests, and electrocardiogram (ECG); * No history of cardiovascular diseases, diabetes, rheumatic connective tissue diseases, or severe liver/kidney dysfunction; * No history of acrocyanosis, no discomfort under cold stimulation, and no previous Raynaud's phenomenon in any part of the body; * No history of taking medications that affect the cardiovascular system. Exclusion Criteria : * Patients with hypertension, diabetes mellitus, hyperthyroidism, arrhythmia, etc. * Patients with connective tissue diseases such as systemic lupus erythematosus, polymyositis, rheumatoid arthritis, etc. * History of blood diseases, severe infections, or other systemic diseases. * Administration of vasoactive drugs within the past month. * Peripheral vascular diseases with arterial occlusion that prevents detection of blood flow signals. * Inability to cooperate with the examination.