DOES AORTIC REGURGITATION AFFECT TRANSMITRAL FLOW - AN ECHO-DOPPLER STUDY

Recent studies suggest that the presence of aortic regurgitation can i nterfere with Doppler measurement of mitral pressure half-time in pati ents with mitral stenosis. Amongst the factors affecting the transmitr al flow in aortic regurgitation a putative role may be played by the m echanical hit of the aortic regurgitant jet impinging on the anterior mitral leaflet, as is very often seen with Doppler Color Flow examinat ion. This study was designed to evaluate the effects of pure aortic re gurgitation on the transmitral flow in patients with normal mitral val ves. We studied 35 patients affected by pure chronic aortic regurgitat ion but with a normal mitral valve and compared them with 30 normal su bjects. In all the patients the aortic regurgitant jet was directed to ward the anterior mitral leaflet. In all the patients and control subj ects a standard echo-Doppler examination was performed, sampling the t ransmitral flow at the level of the tip of the mitral leaflets. In 7 p atients and 11 normal subjects the transmitral flow was also sampled a t the level of the mitral annulus. Patients with aortic regurgitation showed significantly higher values of the mitral pressure half-time (6 1.04 +/- 15.14 vs 50.59 +/- 7.07 ms, P<0.05) and of the time-velocity integral of the total transmitral flow, while the other parameters of transmitral flow, the mitral annulus diameter and the mitral stroke vo lume didn't show statistically significant differences. The comparison of the pressure half-time and time-velocity flow values measured at t he level of the mitral annulus between patients and normal subjects di dn't show significant differences. Finally the comparison between Dopp ler parameters obtained at the tip of the mitral leaflets and those ob tained at the level of the mitral annulus showed, in patients with aor tic regurgitation, higher values of pressure half-time and time-veloci ty integral of transmitral flow at the tip of the mitral leaflets, whi le the same comparisons performed in control subjects didn't show sign ificant differences. The analysis of the results obtained suggest that the presence of aortic regurgitation in patients with normal mitral v alve determines a significant, although not grossly abnormal, prolonga tion of the mitral pressure half-time and that this prolongation seems to be related, at least in part, to the mechanical hit of the aortic regurgitation jet on the anterior mitral leaflet.