Doppler echocardiographic study of porcine bioprosthetic heart valves in the aortic valve position in patients without evidence of cardiac dysfunction

To study the natural history of the hemodynamic performance of bioprostnetic heart valves, Doppler echocardiograms were recorded in a group of clinically stable patients at 2 and 5 years after replacement of native aortic valves with bioprostnetic valves. Eighteen patients completed a 2-year and 26 patients a 5-year follow-up examination. The effective orifice areas of identical models of bioprosthetic valves (Hancock II) were determined in vitro in a left-sided heart pulse duplicator system. In vivo Doppler-derived effective orifice areas were compared with the in vitro measurements for the same valve size. At both the 2- and 5-year followup examinations, the Doppler-derived effective orifice area was significantly less than the in vitro area (p < 0.0001 at each interval). Ten of 16 valves evaluated serially decreased >0.20 cm² in the Doppler-derived effective orifice area between studies. The mean decrease in effective orifice area in valves evaluated serially was 0.25 ± 0.29 cm² (p < 0.005). The peak transaortic gradient increased from 21 ± 6 to 27 ± 8 mm Hg (p < 0.01). The mean transaortic gradient increased from 12 ± 4 to 15 ±7 mm Hg (p < 0.05). It is concluded that serial Doppler echocardiographic studies demonstrate a deterioration in the hemodynamic performance of bioprostnetic valves over time in patients with no symptoms or signs of valvular dysfunction and that Doppler echocardiography may be useful for identifying subclinical bioprostnetic valvular dysfunction.