Analysis of Specified Bernoulli Constant for Semilunar Valve Stenosis in Humans.

Background And Aim Of The Study: To date, no study has determined the specified Bernoulli constant (K) and validated the simplified Bernoulli equation for semilunar valve stenosis by simultaneous measurement of peak jet flow velocity and maximum pressure gradient in humans.

Methods: Using multisensor catheters, the relationship between the peak jet flow velocity (V) and maximum-pressure gradient (max-PG) across the stenosis were analyzed, and K-values calculated for patients with pulmonary (n = 37) and aortic (n = 6) valve stenosis, who were stratified by max-PG into two groups: max-PG 50 mmHg (n = 28; group A) and those with max-PG > 50 mmHg (n = 15; group B).

Results: The specified constant K obtained for max-PG with peak jet flow velocity squared (V2) was 3.9, which was very close to the simplified Bernoulli constant (= 4.0), with a wide distribution in K-value for max-PG (median [interquartile range]: 3.9 [3.0-4.5]). Although there were no significant differences in specified K-values between two groups (p = 0.216), the values of K were significantly more widely scattered in group A than in group B (3.4 [2.5-4.8] versus 4.1 [3.8-4.4]; p < 0.001).

Conclusion: The study results confirmed that, the more severe the stenosis the better suited the simplified Bernoulli constant (K = 4.0) could be for assessing semilunar valve stenosis. This result is consistent with the fluid-mechanical theorem that the kinetic energy of the jet (1/2) ρV92) (= 4.0V(2)) produced by the stenosis disappears completely only downstream of the severe semilunar valve stenosis.