Assessment of the severity of aortic stenosis: comparison of gradient and valve area

Hemodynamic data, including simultaneously measured left ventricular pressure, aortic pressure, and cardiac output, were obtained in 17 patients with isolated valvar aortic stenosis, before and during infusion of dobutamine, isoprenaline, dopamine, and pacing. Infusion of sympathomimetic drugs resulted in a significant increase of both mean and peak systolic aortic valve gradient, cardiac output, heart rate, and systolic aortic valve flow per second. On the other hand, the calculated aortic valve area did not change significantly in spite of variable alterations of all values used for calculating aortic valve area and different causes of hemodynamic changes induced. Aortic valve area is considered a better indicator of the severity of aortic stenosis than is the aortic valve gradient and thus a more suitable indicator for operation.