Accuracy of computer-based quantification of aortic valve stenosis.

In patients with aortic valve stenosis, the quantification of stenosis is usually performed using fluid-filled catheters and a computerized calculation program. The aim of this study was to determine the accuracy of this technique in comparison to the manual planimetry of the area between the curves of a simultaneous registration, using a multitip micromanometer catheter. The study was performed in 19 patients, in whom left and right heart catheterization was warranted. Systolic left ventricular and aortic peak pressures were significantly overestimated using a fluid-filled catheter (206 +/- 35 vs. 199 +/- 37 mm Hg, P = 0.0003, and 148 +/- 18 vs. 143 +/- 21 mm Hg, P = 0.0052). However, peak-to-peak pressure gradients were identical comparing both techniques (58 +/- 31 vs. 56 +/- 32 mm Hg, r = 0.983). The mean pressure gradients and aortic valve areas based on simultaneous measurements of left ventricular and aortic pressures by micromanometer catheters were identical to the values determined by a computer-based program using fluid-filled catheters (54 +/- 21 vs. 52 +/- 21 mm Hg, r = 0.923, P < 0.05, and 0.75 +/- 0.25 vs. 0.77 +/- 0.25 cm2, r = 0.935). Thus, the conventional use of fluid-filled catheters and of a computerized calculation of aortic valve area is valid for quantification of aortic stenosis in patients with sinus rhythm and without significant aortic regurgitation.