Measurement of severity of aortic stenosis experimentally produced in dogs without inserting a catheter into the left ventricle.

When flow passes through an orifice, pressure loss does not occur in the laminar core of the jet distal to the stenosis, but occurs in the region more distal to the stenosis, where the laminar core disappears and turbulence develops. Therefore, if total pressure is measured in the laminar core of the jet some distance downstream of a stenotic aortic valve, it should be equal to total pressure on the left ventricular side of the aortic valve. An experimental study was performed in 5 dogs to test this hypothesis. The results revealed that left ventricular pressure during the ejection period can be determined by measuring the pressure in the laminar core. A preliminary evaluation of the clinical applicability of our method was performed during catheterization in a patient with severe aortic valve stenosis. In this case, the pressure obtained in the jet downstream of the aortic valve was slightly lower than that obtained in the left ventricle.