Improvement of fetal pulmonary hypertension and maturity after reversal of ductal constriction: a prospective cohort study.

OBJECTIVES To test the hypothesis that estimated mean pulmonary artery pressure (MPAP) decreases and pulmonary vascular maturation assessed by the ratio of pulmonary artery flow acceleration time and ejection time (AT/ET) increases after reversal of fetal ductus arteriosus constriction, by suspension of the causal agent (polyphenol-rich foods or nonsteroidal anti-inflammatory drugs), and that these effects are independent of evolution of gestational age, inferences not yet demonstrated in the clinical setting. METHODS This is a prospective cohort study, comparing Doppler echocardiographic ductal flow dynamics parameters, MPAP and AT/ET in 70 third trimester fetuses at the moment of ductal constriction diagnosis and after 2 weeks of discontinuation of prostaglandin inhibitors. MPAP was estimated by Dabestani equation [PMAP = 90 - (0.62 x AT)] and vascular maturity by AT/ET ratio, according to reported validations. Statistical analysis utilized t test for comparison of the variables at diagnosis and after reversal of ductal constriction. Variations of MPAP and AT/ET at these 2 moments were also compared to the expected variations at the same gestational period in normal fetuses according to control reference curves of both variables constructed in 305 normal fetuses from normal pregnant women encompassing the third trimester. RESULTS Normalization of mean systolic and diastolic ductal velocities (1.86 ± -0.34 to 1.38 ± 0.41 m/s, p<0.0001 and (0.41 ± 0.11 to 0.21 ± 0.065 m/s, p<0.0001, respectively) and of pulsatility index (1.99 ± 0.20 to 2.55 ± 0.42, p<0.0001) was demonstrated after 2 weeks. In this period, mean MPAP decreased (66.7 ± 6.90 to 54.5 ± 6.70 mmHg, p< 0.0001), and AT/ET ratio at the pulmonary artery increased (0.20 ± 0.06 to 0.33 ± 0.07, p< 0.0001). Variation of mean MPAP was -12.3 ± -0.30 mmHg, p<0.001 (variation in normal fetuses in 2 weeks in the same gestational period = -2.3 ± -0.19 mmHg [5.3 times more]), and variation of pulmonary AT/ET was 0.14 ± 0.08, p<0.001 (variation of AT/ET in normal fetuses in the same gestational period = + 0.015 ± 0.08, [9.3 times more]). CONCLUSION Resolution of fetal ductal constriction is followed by fall in the estimated mean pulmonary artery pressure and by increase in pulmonary vascular maturity, in a significant higher degree than the observed in normal fetuses in the same gestational age evolution period. This article is protected by copyright. All rights reserved.