[Comparison of pulsed and continuous Doppler techniques for the evaluation of left ventricular stenoses]

The authors compared the data obtained with pulsed (pulsed Doppler-Scanner 3 MHz) and continuous wava Doppler (2.5 MHz), with that obtained by catheterisation in the evaluation of severity of valvular stenoses. The study material comprised 10 healthy subjects and 45 patients with mitral (21) and aortic (24 cases) stenosis, all of whom underwent catheterisation. Stenosis was graded in 3 degrees of increasing severity based on the catheter data. In addition, we studied the correlations between the transvalvular mitral and aortic pressure gradients, calculated by continuous Doppler and catheterisation, and the time of half decrease of flow measured by continuous Doppler and the mitral surface area calculated by catheterisation. No abnormality Was noted in the healthy patients. The jet of the aortic stenosis could not be recorded by continuous Doppler in 8 cases and aortic flow could not be recorded in 1 case with pulsed Doppler. The linear correlation with continuous Doppler was 0.96 (aortic transvalvular gradient for the 16 jets obtained), 0.81 (mitral transvalvular gradient), and 0.80 (time of half decrease of flow and mitral surface area calculated with catheterisation). The comparative study of the degree of severity gives the following percentages of success: mitral stenosis, 85% (pulsed Doppler) vs 71% (continuous Doppler) for mitral stenoses; aortic stenoses 83% (pulsed Doppler) vs 58% (continuous Doppler). In the 16 cases where the aortic jet was recorded properly this percentage was 87% (continuous Doppler) vs 81% (pulsed Doppler). In conclusion, the advantage of continuous Doppler over pulsed Doppler is that it provides quantitative parameters in correlation with catheter data. It is mainly used for evaluating recording the jet should significantly suggest that in elderly patients a systematic right parasternal approach in the jet should significantly reduce the failure rate observed in this study. It is of more limited value in mitral stenoses where pulsed Doppler gives more detailed information about the flow through the mitral valve. This, and the fact that pulsed Doppler can also be used for assession of aortic stenoses, illustrate the complementary nature of the two technique which should always be used together.