Pulsed Doppler derived indices in predicting noninvasively, pulmonary arterial pressures

The pulsed doppler (P.D.) signals obtained in RVOT just below the pulmonary leaflets were used to calculate acceleration time (AcT), pre-ejection period (PEP) and their ratios. These indices were correlated in 31 patients (2 1/2-49 yrs. age) having varying cardiac lesions to Pulmonary arterial pressure (P.A.P) measured during cardiac catheterisation. The mean values of AcT for those with normal PAP was 137 +/- 19.9ms, as compared to 105 +/- 37 ms in those in whom PAP greater than 20mm of Hg. (t = 3.0.p less than .01). The P value was less than 0.001 when comparison was between normal PAP and severe PH. The ratios of PEP upon AcT was 0.87 +/- 0.18 for normal PAP, as compared to 1.39 +/- 0.74 in those with PH (t = 0.31, p less than 0.01). The PEP/AcT predicted systolic PAP 35.49 PEP/AcT + 3.22 (r = 0.77, p less than 0.001). The mean PAP was best predicted by 23.94 PEP/AcT + 2.44 (r = 0.75, p less than 0.001). The quantitative assessment showed presence of presystolic 'a' wave in all with normal PAP; this was absent in all the 9 patients with severe PH (MAPA greater than 40mm of Hg.). We conclude that noninvasively obtained P.D. derived indices can help accurately to predict PAP.