The hemodynamic changes that occur are complex; however, the ultimate result is a decrease in left ventricular preload ... to reduce afterload for diagnostic purposes in the cardiac ...

Cardiac pressor agents ... to a pure increase in arterial afterload, which in the intact circulation is typically offset by concomitant increases in preload and contractility.

Furthermore, a careful review of the patient's medications should be carried out. The patient with severe aortic stenosis is relatively "afterload fixed and preload dependent" -- meaning cardiac ...