BACKGROUND There is an incomplete understanding of the natural course of mild to moderate aortic stenosis (AS). We aimed to evaluate the natural course of patients with mild to moderate AS and its association with coronary artery disease (CAD).

METHODS We retrospectively analyzed 787 patients diagnosed with mild to moderate AS using echocardiography between 2004 and 2010. Cardiac death and aortic valve replacement (AVR) for AS were assessed.

RESULTS A median follow-up period was 92 months. Compared to the general population, patients with mild to moderate AS had a higher risk of cardiac death (hazard ratio [HR], 17.16; 95% confidence interval [CI], 13.65-21.59; P < 0.001). Established CAD was detected in 22.4% and associated with a significantly higher risk of cardiac mortality (adjusted HR, 1.62; 95% CI, 1.04-2.53; P = 0.033). The risk of cardiac death was lower when patients were taking statin (adjusted HR, 0.64; 95% CI, 0.41-0.98; P = 0.041), which was clear only after 7 years. Both patients with CAD and on statin tended to undergo more AVR, but the difference was not statistically significant (the presence of established CAD; adjusted HR, 1.63; 95% CI, 0.51-3.51; P = 0.214 and the use of statin; adjusted HR, 1.86; 95% CI, 0.76-4.58; P = 0.177).

CONCLUSION Mild to moderate AS does not have a benign course. The presence of CAD and statin use may affect the long-term prognosis of patients with mild to moderate AS.