Abstract
Abstract: :
Purpose:To estimate the changes in the retrobulbar blood flow throughout pregnancy and postpartum by means of Color Doppler Imaging (CDI) and to evaluate the influence of general hemodynamic changes on ocular blood flow. To our knowledge this is the first longitudinal CDI study of retrobulbar blood flow in pregnancy and postpartum. Methods: Flow measurements at five intervals from week 12 to week 36 in normal pregnancy and day two and month six postpartum. CDI of the ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary artery (PCA) was performed. Peak systolic (PSV) and end diastolic (EDV) flow velocities in the arteries were measured and the resistive index (RI) was calculated. Mean blood pressure (MAP), pulse rate (PR) and intraocular pressure (IOP) were also measured. One–way repeated measures ANOVA statistic procedure was used to evaluate change over time. A post–hoc Bonferroni test was performed. A p value < 0.05 was considered significant. Results: Twenty–nine healthy subjects (mean age: 30.3+ 3.5 years) were recruited. RI in CRA and PCA decreased significantly with advancing gestational age (p<0.001). The CRA EDV and PCA PSV increased significantly (p<0.001 and p=0.048, respectively). There was a large strength of negative correlation between EDV and RI for all three vessels. A significant correlation between MAP and OA RI was observed, but this was not the case for CRA and PCA. No significant correlation between IOP and the RI was found in pregnancy. CRA RI decreased and CRA EDV increased significantly (p<0.001) from week 12 to month 6 postpartum. Conclusions: We found statsitically significant changes in the retrobulbar blood flow during pregnancy and postpartum. IOP and MAP correlate less with the blood flow velocity changes than expected, suggesting that other mechanisms superseding the general hemodynamic differences are involved in the regulation of retrobulbar circulation.
Keywords: blood supply • imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)