Even without coronary artery disease, aortic stenosis causes compensatory ventricular hypertrophy. Ventricular hypertrophy causes an increase in oxygen demand as well as compression of the vessels traversing the cardiac muscle, resulting in decreased oxygen supply. The result is relative ischemia of the myocytes. Finally, in the case of calcified aortic valves, calcium emboli can cause coronary artery obstruction, although this is rare.