Relationship of maternal ophthalmic artery Doppler with uterine artery Doppler, hemodynamic indices and gestational age: prospective MATERA study

Objectives: To examine the relationship of ophthalmic artery (OA) Doppler indices with uterine artery (UtA) Doppler indices, selected maternal hemodynamic parameters and gestational age, and to evaluate the intraobserver reproducibility of OA Doppler indices. Methods: This was a prospective cohort study of women recruited between 11 + 0 and 23 + 6 weeks' gestation using a stratified and random sampling approach to ensure adequate distribution across the gestational-age range. OA pulsatility index (PI), first peak systolic velocity (PSV1), second peak systolic velocity (PSV2) and peak systolic velocity ratio (PSV ratio), calculated as PSV2/PSV1, were measured twice in each eye by the same observer. UtA-PI was also measured twice on each side by the same observer. Maternal hemodynamic assessment was undertaken using an ultrasonic cardiac output monitor (USCOM 1A). Pearson's and Spearman's rank correlation coefficients were used to assess the correlations between variables, and Bland–Altman plots were used to evaluate the intraobserver reproducibility of OA Doppler indices. Results: Of 194 women invited to participate in the study, 169 were eligible for inclusion, of whom 16 were excluded following an obstetric ultrasound scan and a further three owing to inadequate or incomplete OA or UtA Doppler assessment, leaving 150 women in the final analysis. Log UtA-PI had a weak correlation with both OA-PI (r = –0.19 (95% CI, –0.34 to –0.03), P = 0.021) and OA-PSV ratio (r = 0.31 (95% CI, 0.15–0.45), P < 0.001). The correlation between gestational age and OA-PI was non-significant (r = 0.14 (95% CI, –0.03 to 0.29), P = 0.097), and that between gestational age and OA-PSV ratio was weak (r = –0.23 (95% CI, –0.38 to –0.07), P = 0.004), as opposed to the strong correlation between gestational age and UtA-PI (r = –0.68 (95% CI, –0.76 to –0.58), P < 0.001). No strong correlations were observed between OA-PI or OA-PSV ratio and maternal hemodynamic indices. The correlations were unaltered by adjustment for maternal age and body mass index. The intraobserver reproducibility of OA-PI and OA-PSV ratio in the same eye was high. The correlation between the right and left eyes was moderate for OA-PI (r = 0.63 (95% CI, 0.53–0.72), P < 0.001) and strong for OA-PSV ratio (r = 0.81 (95% CI, 0.75–0.86), P < 0.001). Conclusions: OA-PI and OA-PSV ratio had a weak or no correlation with UtA-PI and maternal hemodynamic parameters, meaning that they can be used as independent predictors for pre-eclampsia. Gestational age had no clinically relevant effect on OA-PI and OA-PSV ratio, suggesting that these indices could be measured without adjustment at any time between 11 and 23 weeks' gestation. OA Doppler indices had high intraobserver reproducibility and were strongly correlated between the right and left eyes.