A new method of evaluating the degree of stenosis using a multisensor catheter. Application of the pressure loss coefficient.

A new method of evaluating the degree of stenosis using the pressure loss coefficient is presented here. The pressure loss coefficient was obtained in patients with pulmonary or aortic stenosis by measuring the pressure and velocity of the blood simultaneously with a multisensor catheter. Although the pressure gradient across the stenosis was augmented by increasing the blood velocity with pharmacological loading, the pressure loss coefficient remained nearly constant. This confirmed that the pressure loss coefficient is more appropriate for evaluating the degree of stenosis than the pressure gradient, which depends on the blood velocity. The pressure loss coefficients obtained from the preoperative and postoperative catheterization data were compared to evaluate the effects of the surgical operation. A pressure loss coefficient of 15 was proposed as the critical value for the indication of operation.