Exertional angina is common symptom in patients with severe aortic stenosis (AS) without obstructive coronary artery disease (CAD). Although reduced myocardial flow reserve is one of the proposed explanations for angina, little is known about the pathophysiology.

This study aimed that adenosine-stress cardiac magnetic resonance can be used for the assessment of myocardial perfusion reserve and suggest the pathophysiology of development of angina in patients with severe AS without obstructive CAD.

Inclusion Criteria:

1. severe AS
2. normal LV ejection fraction (EF ≥ 50%)

Exclusion Criteria:

1. age <18
2. LVEF < 50% in echocardiography
3. concomitant other valvular disease of moderate or severe severity
4. previous aortic valve replacement
5. symptomatic patients other than chest pain
6. obstructive CAD (>30% luminal stenosis in at least one coronary artery on coronary angiography)
7. history of myocardial infarction or acute coronary syndrome
8. contraindication to adenosine
9. any absolute contraindication to CMR
10. estimated glomerular filtration rate <30 mL/min/1.73m2.

Subjects who had severe AS and normal LV ejection fraction (EF ≥ 50%) in transthoracic echocardiography were included in the investigators' prospective study. Severe AS was defined as aortic valve area index less than 0.6 cm2/m2 as previously published.