The purpose of this study is to explore the relationship between periodontal disease and coronary artery disease through changes in the gut microbiome. In addition, the investigators aim to find possible periodontal pathogens that have association with cardiovascular disease.

The previous studies have reported the associations among cardiovascular disease, periodontitis, and gut microbiome dysbiosis. However, there is a lack of evidences about the axis of association from oral-gut-cardiovascular disease. The investigators hypothesized that periodontal disease might induce dysbiosis of gut microbiome and dysbiosis might have a role in cardiovascular disease (as called "oro-gut-vascular axis"). The investigators aim to prove this hypothesis through this case-control, cross-sectional study.

Inclusion Criteria:

-Patients aged from 19 to 80 years who underwent invasive coronary angiography for clinical necessity, with informed consent

Exclusion Criteria:

• Patients with prosthetic valve
• pregnancy
• active malignancy
• active autoimmune disease
• active inflammatory bowel disease
• chronic kidney disease (eGFR<30, or on dialysis)
• Active liver disease or liver cirrhosis
• consistent use of probiotics
• prior gastrointestinal surgery within 1 year

Patients aged from 19 to 80 years who underwent invasive coronary angiography for clinical necessity in single tertiary hospital