Table 1.

Study inclusion and exclusion criteria

Inclusion criteria

1. Participant must be older than 18 years

2. Patients with angina pectoris, who has risk factors for CMD (diabetes, metabolic syndrome, cardiac hypertrophy, female)

3. Written informed consent available

4. Participant is indicated for invasive coronary angiography

5. Participant needs to be taken within 30 days after enrollment

Exclusion criteria

1. Previous PCI or CABG

2. Participant is not eligible for measuring IMR

3. Complicated complex congenital heart disease

4. Artificial pacemaker or internal defibrillator leads implanted

5. Implanted artificial heart valve

6. Severe arrhythmia including complete AV block, ventricular arrhythmia

7. Impaired chronic renal function (serum creatinine >1.5 ULN)

8. Allergic to iodine

9. Pregnancy

10. Body mass index >35 kg/m2

11. Needs for emergency procedures

12. Left ventricle is markedly thickened

13. Severe distortion of the blood vessel

14. Unstable hemodynamics including abrupt chest pain cardiogenic shock, unstable blood pressure (systolic <90 mmHg), severe congestive heart failure or pulmonary edema

15. Life-threatening diseases (life expectancy <2 months)

16. Tako Tsubo syndrome (TTS)

17. Inappropriate subject judged by clinician

CMD, coronary microvascular dysfunction; PCI, percutaneous transluminal coronary intervention; CABG, coronary artery bypass grafting; IMR, index of microcirculatory resistance.