The application of Doppler echocardiography to the study of valvular function has recently been extended to include prosthetic valves. We have used Doppler echocardiography to evaluate 40 patients with porcine mitral valves (PMV) implanted 0.5 to 99 months prior to examination. Three parameters of PMV flow were assessed: maximum diastolic left ventricular inflow velocity (Vmax), pressure half-time (P 1 2t), and presence or absence of mitral regurgitation (MR). Normally functioning PMV (n = 29) were characterized by Vmax ≤ 180 cm/sec and P 1 2t ≤ 160 msec. Within this group, P 1 2t was not correlated significantly with the age of the patient nor with prosthesis size. Doppler correctly identified all 10 patients with MR. Among these 10 patients, Vmax was 206 ± 53 cm/sec, significantly higher than the mean observed in normally functioning prostheses (136 ± 24 cm/sec, p < 0.001). In eight patients with stenosis of the PMV, mean P 1 2t was 220 ± 63 msec, and in seven of eight, it was ≥ 180 msec (p < 0.001 compared to normals). We conclude that: (1) Vmax ≤ 180 cm/sec, P 1 2t ≤ 160 msec, and absence of systolic turbulence in the left atrium characterize normally functioning PMV; (2) P 1 2t ≥ 180 msec identifies patients with stenosis of the PMV; and (3) Doppler echocardiography can detect MR and separate mitral from tricuspid regurgitation.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine