NONINVASIVE ASSESSMEMT
OF PULMONARY HEMODYNAMICS
Chen SB
Dept. of
Pediatric Cardiology, XinHua Hospital,
Shanghai
Children's Medical Center,
Shanghai
Second Medical University, Shanghai, China
Assessment of pulmonary arterial pressure Doppler echocardiographic
methods for assessing pulmonary arterial pressure fall under 3 basic
categories, namely, right ventricular isovolumic relaxation time,
calculated pressure gradient derived from abnormally developed blood flow
and pulmonary systolic flow indexes. One study found estimation of
pulmonary arterial pressure by measurement of peak tricuspid regurgitation
velocity superior to other doppler techniques. But, it is difficult to have
good results in the presence of very mild tricuspid regurgitation or eccentric
regurgitant jet. In 1989, Morera et al. described a method to estimate
pulmonary arterial pressure as a fraction of systemic arterial pressure. It
is a universally applicable and accurate method for estimation of pulmonary
arterial pressure, and could also provide absolute pressure value. But
there are too many parameters in the calculation. We have done further
study to simplify this method. Eliminating peak flow velocity from the F
described by Morera could simplify this method and improve its accuracy.
Feasibility of pulmonary arterial pressure estimation from doppler
ultrasound audio signals. Currently, all time interval parameters of aortic
and pulmonary flow for estimation of pulmonary arterial pressure are
calculated from aortic and pulmonary flow velocity spectrum which are
doppler video signals. Its transit-time broading effect may cause frequency
shift errors and amplitute distortion. Compared with doppler video signal,
doppler audio signal is less affected, could be used to generate flow tracing,
for automatically measuring time interval parameters. Comparative study of
pulmonary arterial pressure, pulmonary blood flow and pulmonary vascular
resistance measured respectively by doppler echocardiography (DE), doppler
audiosignal processing system (DASPS) and cardiac catheterization was done.
PASP, PAMP measured by DASPS highly correlated with those measured by
cardiac catheterization(r=0.98, 0.95, respectively). Reproducibility of
DASPS was much better than that of doppler echocardiography. It did take
less time to estimate pulmonary arterial pressure by DASPS (5.1?.7min) than
by doppler echocardiography (21.5?.3min). In conclusion, doppler audio signal processing system
adopting pulmonary to aortic time interval ratio could be used as an accurate
and universal method for estimation of pulmonary arterial pressure.