Pulmonary arterial Doppler velocimetry in fetuses with lung hypoplasia

Objective: The aim of the study was to examine Doppler flow velocity wavefo rms in the main stems of the pulmonary arteries in fetuses with autopsy-pro ven lung hypoplasia and to find out whether in these conditions typical pat terns can be found. Study design: Doppler spectra were derived from the mai n stem of the right or left pulmonary artery in fetuses at high-risk for lu ng-hypoplasia. The following Doppler parameters were analyzed and compared to reference ranges: peak systolic velocity, acceleration time, time veloci ty integral, end-systolic reverse flow, pulsatility index (PI). Pulmonary h ypoplasia was found in nine cases at autopsy after termination of pregnancy (19-23 weeks). According to etiology, three groups were considered: (A) bi lateral renal malformations (n=4), (B) congenital diaphragmatic hernia (n=2 ), and (C) miscellaneous malformations including heart defects (n=3). Resul ts: The following Doppler parameters were found: normal values in end-systo lic reversal flow in all cases, decreased peak systolic velocity and accele ration time in 3/9, decreased time velocity integral in 4/9 and increased p ulsatility index in 6/9. Considering the etiology of pulmonary hypoplasia t he pulsatility index was found to be the most sensitive, since all fetuses in groups A and B had an abnormal PI. Conclusions: Human fetuses with renal malformations and diaphragmatic hernia associated with lung hypoplasia sho w as early as 19-23 weeks of gestation an abnormal Doppler spectrum in the main stems of the pulmonary arteries. Increased PI is the best parameter to detect flow abnormality in this condition. Since the Doppler spectrum depe nds on cardiac anatomy and function, PI in lung hypoplasia seems to be reli able only when cardiac defects are absent. (C) 1999 Elsevier Science Irelan d Ltd. All rights reserved.