Rationale, design, and baseline characteristics of a randomized trial to assess the effect of cholesterol lowering on the progression of aortic stenosis: The Aortic Stenosis Progression Observation: Measuring Effects of Rosuvastatin (ASTRONOMER) trial

Background Aortic stenosis (AS) is a common health problem in the western world. Recent studies have suggested that cholesterol lowering may have a salutary effect on the progression of AS. The primary objective of the ASTRONOMER study is to determine whether patients with AS randomized to rosuvastatin will experience less progression in AS severity as measured by aortic transvalvular gradients and valve areas. The secondary objectives are to determine the effect of rosuvastatin on the rate of cardiac death and aortic valve replacement and to assess the time to outcome during a follow-up of 3 to 5 years. Method This is a double-blind placebo-controlled study. Patients with mild to moderate AS are randomized to receive 40 mg/d of rosuvastatin or placebo. Patients with any clinical indication for the use of cholesterol-lowering agents according to the 2000 Canadian guidelines are excluded. Results Recruitment of 272 patients from 23 Canadian sites was completed in December 2005. Compared with patients with AS in published trials, the patients in the ASTRONOMER study are younger (58.1 +/- 13.6 years), have less severe AS (AS jet velocity 3.2 +/- 0.4 m/s), and are composed of a great proportion (48.9%) of patients with bicuspid aortic valve. Conclusions Prevention of the development of severe AS needs to be tested in large randomized studies. Recruitment for the ASTRONOMER trial has been completed and results will be available at the end of 2008.