[Contribution of Doppler echocardiography in the evaluation of normal and pathologic aortic valve prosthesis].

Doppler echocardiography was performed in 112 patients with normal aortic valve prostheses and 13 patients with dysfunction (3 obstructions, 10 regurgitations) confirmed at catheterisation and/or surgery. The maximum and mean transprosthetic pressure gradients were measured in all patients by continuous wave Doppler. The prosthetic valve surface area was calculated by applying the continuity equation in the last 67 patients and compared with the effective surface area deduced from hemodynamic studies in the literature: --There was a great variability in the values of mean pressure gradient and prosthetic valve area within each group and with each size of prosthesis in patients with normal valves. No significant difference was observed between the gradients of different prostheses. However, for a given size, the St Jude Medical prosthesis had larger calculated surface areas than the other prostheses. The Doppler valve surface area did not differ significantly from the area measured invasively for the different categories of prostheses, and it increased with the size of the prosthesis. Mild aortic regurgitation was observed in 16 per cent of bioprostheses and 30 per cent of mechanical prostheses. The three cases of obstruction were characterised by a high mean pressure gradient (59 +/- 16 mmHg, p less than 0.01 vs normal prostheses) and a reduced Doppler surface area (0.7 +/- 0.2 cm2, p less than 0.005 vs normal prostheses) and were correctly diagnosed by Doppler echocardiography. Eight of the ten prosthetic regurgitations were correctly quantified by Doppler. Cardiac Doppler coupled with echocardiography is a very valuable method of non-invasive assessment of aortic valve prostheses.(ABSTRACT TRUNCATED AT 250 WORDS)