Association between uterine artery Doppler velocimetry, placenta accreta spectrum, and depth of placental implantation.

INTRODUCTION: We aim to evaluate uterine artery (UtA) Doppler velocimetry in patients at risk of placenta accreta spectrum (PAS). METHODS: Prospective cohort of patients referred to an academic referral center for suspected PAS. The left and right UtA were evaluated, and mean peak systolic velocity (PSV), end-diastolic velocity (EDV), and pulsatility index (PI) were obtained and converted to gestational age (GA)-adjusted z-scores. Differences in UtA Doppler indices between patients with and without PAS, and among varying degrees of placental implantation depth, were analyzed. The predictive performance of UtA Doppler velocimetry to diagnose PAS and intraoperative bleeding (IOBL) >1500 mL was calculated. A sub-analysis of patients with and without placenta previa was conducted. RESULTS: A total of 177 patients were included, and PAS was confirmed in 61.0% (108/177). In the complete study group, patients with PAS had significantly lower UtA-PI and higher UtA-PSV and UtA-EDV (p < 0.05) than patients without PAS. We found the following associations with PAS: UtA-PSV ≥90th percentile for GA demonstrated an odds ratio (OR) of 4.9 (95% confidence interval [CI], 2.31-10.39; p < 0.0001); UtA-EDV ≥90th percentile for GA demonstrated an OR of 3.49 (95% CI, 1.71-7.14; p = 0.0006); and UtA-PI ≤25th percentile for GA demonstrated an OR of 0.71 (95% CI, 0.23-2.23; p = 0.2). The predictive performance of UtA velocities improved when analyzing only patients without placenta previa. There were no significant differences in UtA Doppler indices related to the placental implantation depth.Patients with severe IOBL (>1500 mL, n = 86) had significantly higher UtA-PSV (p = 0.004) and UtA-EDV (p = 0.0001), but no differences in UtA-PI than those without severe IOBL (n = 79). The association between UtA-PSV ≥90th percentile for GA and severe IOBL demonstrated an OR of 3.67 (95% CI, 1.86-7.23; p = 0.002); UtA-EDV ≥90th percentile for GA demonstrated an OR of 3.34 (95% CI, 1.68-6.64; p = 0.0006). The association between increased UtA velocities and severe IOBL was similar regardless of the presence of placenta previa. CONCLUSIONS: Patients with PAS showed lower UtA-PI and higher UtA-PSV and UtA-EDV than those without PAS. The predictive performance of UtA Doppler velocimetry for PAS seems to improve in patients without placenta previa. Patients who experienced severe IOBL exhibited significantly higher UtA-PSV and UtA-EDV than those without severe IOBL.