Study of the Characteristics of Pulmonary Trunk in Pulmonary Hypertension Secondary to Left Heart Disease Using Pressure-Velocity Loops (PU-Loops).

: Although pulmonary hypertension (PH) caused by left heart disease (PH-LHD) is more common in PH, little is known about its properties of pulmonary artery (PA) in PH-LHD. The purpose of this study was to measure pulmonary regional pulse wave velocity (PWV) and to quantify the magnitude of reflected waves in patients with PH-LHD by the analysis of the pressure-velocity loops (PU-loop). : High-fidelity PA pressure (Pm) and PA velocity (Vm) were measured in 11 subjects with PH-LHD (mean Pm>25 mmHg), 1 subject with atrial septal defect (ASD) without PH and 12 control subjects, using multisensor catheters.

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.

Validity of the Water Hammer Formula for Determining Regional Aortic Pulse Wave Velocity: Comparison of One-Point and Two-Point (Foot-to-Foot) Measurements Using a Multisensor Catheter in Human.

Background: Lack of high-fidelity simultaneous measurements of pressure and flow velocity in the aorta has impeded the direct validation of the water-hammer formula for estimating regional aortic pulse wave velocity (AO-PWV1) and has restricted the study of the change of beat-to-beat AO-PWV1 under varying physiological conditions in man.

Methods: Aortic pulse wave velocity was derived using two methods in 15 normotensive subjects: 1) the conventional two-point (foot-to-foot) method (AO-PWV2) and 2) a one-point method (AO-PWV1) in which the pressure velocity-loop (PV-loop) was analyzed based on the water hammer formula using simultaneous measurements of flow velocity (Vm) and pressure (Pm) at the same site in the proximal aorta using a multisensor catheter. AO-PWV1 was calculated from the slope of the linear regression line between Pm and Vm where wave reflection (Pb) was at a minimum in early systole in the PV-loop using the water hammer formula, PWV1 = (Pm/Vm)/ρ, where ρ is the blood density.