Coronary microvascular dysfunction (CMD) carries an increased risk of adverse cardiovascular clinical outcomes. The association between fundus microcirculation changes and coronary microcirculation is not well understood. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) is a new type of optical diagnostic imaging technology for non-invasive detection, which can perform multi-dimensional quantitative assessment of fundus microcirculation. In this study, investigators intend to use the coronary angiography-derived index of microvascular resistance (caIMR) to screen patients with CMD, explore the relationship between relevant parameters based on OCT and OCTA measurements and caIMR, and evaluate the feasibility and clinical value of non-invasive identification of CMD through fundus OCT and OCTA.

Coronary microvascular dysfunction (CMD) is defined as the clinical syndrome of angina and electrocardiographic ischemic changes in the absence of obstructive coronary artery disease. CMD carries an increased risk of adverse cardiovascular clinical outcomes. Assessment of CMD is performed with different diagnostic modalities, including nuclear myocardial scintigraphy, cardiac magnetic resonance, doppler echocardiography, and coronary microcirculation resistance index techniques. However, current examination techniques have limitations such as radiation risk, high cost, and time-consuming, so they cannot be widely screened in the population. Previous studies have shown that fundus vascular changes were strongly associated with cardiovascular events, but the correlation between fundus microcirculation changes and coronary microcirculation is not well understood. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) is a new type of optical diagnostic imaging technology for non-invasive detection, which use infrared light projection onto fundus tissue to achieve real-time tomographic section imaging, which can perform multi-dimensional quantitative assessment of fundus microcirculation. In this study, investigators intend to use the coronary angiography-derived index of microvascular resistance (caIMR) to screen patients with CMD, explore the relationship between relevant parameters based on OCT and OCTA measurements and caIMR, and evaluate the feasibility and clinical value of non-invasive identification of CMD through fundus OCT and OCTA.

Inclusion Criteria:

1. Patients who underwent coronary angiography in the Department of Cardiology, Peking University First Hospital;
2. Complete baseline clinical information;
3. Subject who have coronary angiography results, which shows coronary stenosis < 50%;
4. Older than 18 years;
5. Subjects who have signed informed consent.

Exclusion Criteria:

1. Present serious fundus disease
2. Severe cataract and other ophthalmic diseases, which affect imaging quality;
3. Target coronary vessels provide collateral circulation for chronic complete occlusive lesions;
4. The target coronary angiography agent is poorly filled, overlapped, or severely distorted, and cannot fully expose the location of the lesion;
5. Coronary angiography images are of poor quality and cannot be identified;
6. Active bleeding state;
7. Severe renal insufficiency, contrast agent allergy, and unable to perform coronary angiography.

Department of Cardiology, Peking University First Hospital