Compound Danshen Dripping Pill for Diabetic Microvascular Angina

Inclusion Criteria: History of type 2 diabetes ≧5 years; Repeated chest pain attacks with typical exertional angina pectoris or resting angina pectoris attacks; Coronary normal or stenosis \<50%; Ischemic depression in ST segment during resting or exercise; Coronary flow reserve (CFR) of the anterior descending coronary artery \< 2.0, or CFR ≧2.0 but acetylcholine activation test is positive; Subjects or their guardians agreed to participate in this study. Exclusion Criteria: Previous myocardial infarction or PCI or CABG treatment; Severe arrhythmia; Refractory hypertension or hypertension accompanied by left ventricular wall thickness \> 12 mm; Familial hypercholesterolemia; Takayasu arteritis, Kawasaki disease or coronary artery malformation; Pregnant or nursing, or having the intention to give birth within one year; Hepatic or renal dysfunction; Allergic to contrast agents or traditional Chinese medicines; Patients who participated in clinical research of other drugs within 3 months before being selected.