Evaluation of the significance of a transvalvular catheter on aortic valve gradient in aortic stenosis: a direct hemodynamic and Doppler echocardiographic study.

We studied 18 patients with aortic stenosis undergoing routine cardiac catheterization to determine the effect of a transvalvular catheter on transaortic pressure gradients. By measuring the Doppler gradients before and after the withdrawal of the pigtail catheter, we demonstrated significant increases in the peak instantaneous and mean gradients when the catheter straddled the valve, an effect that was more pronounced with increasing severity of stenosis.