Second trimester angiotensing-converting enzyme and uterine artery Doppler as predictors of preeclampsia in a high-risk population.

Objective: To investigate whether serum angiotensing-converting enzyme (ACE) and uterine artery Doppler (UAD) are useful markers as predictors of preeclampsia (PE) in a high-risk population.

Methods: Patients at risk of PE (n = 68) were subclassified as having PE (n = 8) or no PE (n = 60). Blood samples were obtained between 19 and 22 weeks of gestation. Doppler ultrasound of the uterine arteries was done at the time of blood sampling. Maternal serum ACE was determined through spectrophotometry assay (A15 Biosystem, ATOM, Barcelona, Spain).

Results: Comparing the group who presented PE with the one who was not developed it, we found significant differences for ACE (54.2 ± 21.2, 38.1 ± 12.3 U/L; p = 0.003); the pulsatility index (PI) (1.2 ± 0, 3.1 ± 0.3; p = 0.032) and resistance index (RI) (0.7 ± 0.1, 0.5 ± 0.1; p = 0.004). The AUC for ACE was 0.724, so we selected the cutoff of 36.5 U/L (sensitivity: 62.5% and specificity: 86.7%). The AUC for PI was 0.652 choosing a cutoff of 1.4 (sensitivity: 57.1% and specificity: 93.1%). The AUC for RI was 0.712 and the cutoff of 0.7 (sensitivity of 71.4% and specificity: 89.6%). The combination that allowed us to increase the diagnostic performance was the ACE+RI with Doppler study, increasing the AUC to 0.872.

Conclusions: ACE, PI and RI as parameters of Doppler study were useful predictors of PE in the second trimester of gestation. The best combination to increase the diagnostic performance was ACE with the RI.