Compelling epidemiological evidence indicates that alterations of mitochondrial DNA, including mutations and abnormal content of mitochondrial DNA (mtDNA), are associated with the initiation and development of cardiovascular disease. This study was undertaken to investigate whether mtDNA copy number in peripheral blood cells could be used as a risk predictor for coronary heart disease.

Inclusion Criteria:

1. History of documented myocardial infarction;
2. Prior coronary revascularization intervention (coronary artery bypass graft surgery or percutaneous coronary intervention);
3. The presence of ≥ 50% stenosis in one or more coronary arteries identified during cardiac catheterization;

Exclusion Criteria:

1. History of malignancy or end-stage renal disease;
2. Blood transfusion within one month or prior bone marrow transplantation
3. Patients who reluctant to sign informed consent

A total of 200 eligible CHD patients were anticipated to include in this study.Moreover, The 200 healthy controls without previous CHD history were also recruited from individuals who visited investigator's hospital for physical examination during the same time period.