[Hemodynamic evaluation of the prosthetic heart valves implanted in the aortic position]

In order to solve the problems of "valve-patient mismatch", hemodynamic problems with prosthetic heart valves implanted in the aortic position, and to clarify suitable size of the prostheses, in vivo hemodynamic studies and studies on the postoperative reduction of left ventricular (LV) hypertrophy were performed in 68 aortic valve replacement patients with various types of prosthetic valves. The pressure gradient across the valve (LV-Ao PG) and effective orifice area (EOA) were measured by perioperative pressure study and by continuous-wave Doppler echocardiography during the postoperative period. The postoperative reduction of LV hypertrophy was evaluated from the reductions of LV mass volume (LVM) on the M-mode echocardiogram, cross sectional area (CSA) on the two-dimensional echocardiogram, CTR on chest X-ray film and SV1 + RV5 on the electrocardiogram. A linear relationship was observed between cardiac output (CO) and LV-Ao PG in each type of prosthetic valve, and the slope of their correlation equation, showing the rate of increase in LV-Ao PG with the increase in CO, was steeper in the prosthesis with a smaller orifice area. The mean value of EOA-echo was 1.4 cm2 in the 19 mm St. Jude Medical valve, 1.6 cm2 in 21 mm Björk-Shiley (BS), 1.9 cm2 in 23 mm BS, 1.7 cm2 in 21 mm Medtronic Hall (MH) and 2.1 cm2 in 23 mm MH.(ABSTRACT TRUNCATED AT 250 WORDS)