Research Of The Characteristics Of Pulmonary Valve Annular Motion Between Normal Children And The Children With Pulmonary Hypertension By Quantitative Tissue Velocity Imaging

Background and Objective:Quantitative tissue velocity imaging (QTVI) which derived from tissue Doppler imaging (TDI) is a new ultrasound technique. Studies have shown that velocity and time parameters of atrio-ventricular annular motion by TDI are related to pulmonary hypertension. In this study, we used QTVI technology to measure velocity and time intervals in pulmonary valve annulus in 101 normal children and 32 children with pulmonary hypertension. We aimed to evaluate the effects of heart rate (HR), body surface area (BSA) and pulmonary valve annular diameters on the QTVI velocity parameters and QTVI time parameters, and tried to find out the difference between normal children and the children with pulmonary hypertension.Methods:A total of 101 normal children and 32 children with pulmonary hypertension were enrolled in this study, who took the health care visits in our hospital from November 2009 to September 2010. We divided normal children into 4 groups:under 3 months of age group,3 months-of age group,1 year-of age group and 6-12 years of age group. The children with pulmonary hypertension were at age from 5 days to 3 years. GE Vivid 7 and GE Vivid 7 Dimension color Doppler scanners with 1.5-8.0 MHz transducers were used to exam the above children, which could analyze and post-process QTVI images with Echopac workstation.Peak velocity of tricuspid regurgitation and pulmonary valve regurgitation were measured by PWD in standard apex four-chamber view and aortic short-axis view. Pulmonary systolic and diastolic pressures were calculated by simple Bernoulli equation. Pulmonary mean pressure and pulmonary vessel resistance were calculated also. The images from aortic short-axis view of pulmonary were recorded for three to five cardiac cycles.The QTVI sample volume was set at the points of pulmonary valve annulus attached to the medial and lateral wall of pulmonary artery to acquire speed-time curve, and it was similar with the curve of tricuspid annulus'. Peak systolic velocity (Sa), peak early(Ea) and late(Aa) diastolic velocity of pulmonary valve annulus were measured, and Ea/Aa ratio was calculated as well. QTVI a component was measured from the starting point of QRS wave in ECG to the leading edge of the subsequent early diastolic pulmonary valve annular QTVI Ea wave. The b component was measured from the leading edge of the systolic pulmonary valve annular QTVI Sa wave to the trailing edge of the Sa wave. The Tei index determined by QTVI method was calculated as (a-b)/b.Results:(1) In normal children:The value of Ea increased with the age before 1 year-of age, but was stable in other groups. The ratio of Ea/Aa was less than 1 at the age of under 3 months(the point of medial wall:0.82±0.21,the point of lateral wall:0.81±0.24), while more than 1 at other ages. It rapidly increased with children growing.(2) In normal children:Sa, Ea, Aa, Ea/Aa correlated significantly with HR, BSA and pulmonary valve annular diameter.(3) There was significant variance of QTVI-Tei index in the children with pulmonary hypertension.(4) Paired samples test was used in this study between normal children and the children with pulmonary hypertension. And it had shown that there was significant variance of the time parameters between normal children and the children with pulmonary hypertension (P<0.01).(5) Ea measured at the point of pulmonary valve annulus attached to the medial wall of pulmonary artery was obviously lower in children with pulmonary hypertension, and so was Ea/Aa measured at the points of pulmonary valve annulus attached to the medial and lateral wall of pulmonary artery.Conclusions:(1) We acquired pulmonary valve annular motion curve (speed-time curve) by using QTVI technology. It was similar with the curve of tricuspid annulus':peak systolic velocity (Sa), peak early (Ea) and late (Aa) diastolic velocity.(2) QTVI velocity and time parameters developed with age in childhood, particularly rapidly in infants. This study indicated the reference of normal values of QTVI velocity and time parameters of pulmonary valve annulus in children under 12 years old.(3) In the QTVI velocity parameters of pulmonary valve annulus, the value of Ea and the ratio of Ea/Aa decreased with the resistance of pulmonary vessel.(4) QTVI-Tei index measured at the pulmonary annulus increased in the children with pulmonary hypertension, and it might be a new indicator to estimate the level of the pulmonary pressure.