[Phono-mechanographic evaluation of aortic stenoses. Contribution of the B1-maximum murmur/B1-B2 index].

The diagnostic value of phonomechanography in valvular aortic stenosis was reassessed with a rarely used index, the ratio S1-maximum intensity of the systolic murmur/S1-S2, or Thiron's index, the author of which only studied the correlations with the aortic transvalvular pressure gradient. The results obtained by the author being considered inconclusive, we decided to examine its correlations with aortic valve surface area calculated with the Gorlin's formula. The study was carried out in 38 patients with pure aortic stenosis, in whom 4 phonomechanographic parameters, the corrected left ventricular ejection time (Meiners), the carotid pulse half peak time, the S1-maximum intensity of the murmur interval and Thiron's index, were compared with the transvalvular pressure gradient and the aortic valve surface area at catheterisation. The first two parameters mentioned above were of limited value (correlations with aortic valve surface area r = 0.315, p less than 0.05 and r = 0.477, p less than 0.01 respectively). On the other hand, a good correlation was obtained with Thiron's index (r = 0.624, p less than 0.001) which was better than that found with the interval between S1 and maximum intensity of the systolic murmur (r = 0.483, p less than 0.001) in a population not excluding subjects with cardiac failure. These results indicate that: when Thiron's index less than or equal to 0.45, the aortic stenosis is probably mild (aortic surface area greater than 0.8 cm2), when Thiron's index is 0.46 greater than 0.56, the aortic stenosis is likely to be moderately severe (aortic surface area 0.8 less than 0.5 cm2), when Thiron's index is greater than 0.57, the aortic stenosis is probably severe (aortic surface area less than 0.5 cm2). In our series, Thiron's index was the best phonomechanographic parameter for the assessment of pure aortic stenosis. It could not be calculated in 10 out of 48 patients; this drawback was not encountered with the corrected left ventricular ejection time or the carotid pulse half peak time.(ABSTRACT TRUNCATED AT 250 WORDS)