Non-obstructive coronary heart disease refers to patients with angina pectoris without significant narrowing of the epicardial vessels. Coronary microvascular disease(CMD) is a kind of non-obstructive coronary heart disease, and its clinical detection rate is increasing, seriously affecting the quality of life of patients, and increasing the risk of cardiovascular adverse events, but its mechanism has not been fully understood. This study will prospectively collect patients who meet the diagnosis of CMD, observe the development and outcome of the disease, and explore its occurrence and development mechanism.

Inclusion Criteria:

1. Angina symptoms
2. Objective evidence of myocardial ischemia
3. Coronary angiography was normal,irregular tube wall, or stenosis <50%

Exclusion Criteria:

1. People under the age of 18
2. Non-cardiogenic chest pain and other heart conditions such as variant angina, cardiomyopathy, myocarditis or valvular heart disease

The patient had obvious symptoms of angina pectoris, but coronary angiography showed no obvious epicardial stenosis, and auxiliary examinations such as ultrasound, CTP,CMR, PET, SPECT, and coronary function examination indicate the presence of microcirculation dysfunction