Abstract
Purpose :
Preeclampsia (PE), one of the most serious complications of pregnancy, is characterized by hypertension, proteinuria, and edema. The placenta and the choroid have remarkably similar characteristics. As PE is a disease of the vasculature, and the eye is a readily accessible target for non-invasive imaging, we investigated pulsatile flow characteristics in the choroid, central retinal artery (CRA) and vein (CRV) and short posterior ciliary artery (SPCA) in a cohort of patients with PE, chronic hypertension (HTN) and normal controls.
Methods :
We performed plane-wave imaging of the eye with a Verasonics Vantage 128 ultrasound system using an 18 MHz linear array probe. For the retrobulbar vessels, two angled plane-waves were added to form 6000 compound images/sec. Choroidal imaging was performed in a plane just superior to the optic nerve, adding 10 angled plane-waves to form 1000 compound images/sec. Scans were performed in duplicate on both eyes within 72 hours post-partum on 8 PE, 4 HTN and 9 control patients. Blood pressure (BP) in PE and HTN patients was medically controlled at the time of examination. Peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (Vm), resistive Index (RI) and pulsatile index (PI) were determined from spectrograms of flow velocity over the 3-second period of data acquisition.
Results :
Comparing PE and control patients, significant differences were found in PSV in the CRV (p=.035), in Vm in the CRA (p=.018), in EDV in the CRA (p=.026) and SPCA (p=.038), and in RI and PI in the CRA (p=.015 and .007) and SPCA (p=.012 and .016), with higher velocities and lower resistance in PE than controls. We did not find significant differences in choroidal flow between these groups, however choroidal flow was significantly higher in HTN than controls or PE.
Conclusions :
Significant differences in flow velocity and pulsatility were observed in the retrobulbar vessels in PE versus control eyes, but choroidal differences were not significant. Although differences in choroidal flow were seen in HTN, this result should be viewed with caution because of the small HTN sample size. This study was performed post-partum in patients with BP under control. Hence, larger differences might be present during acute PE. Nevertheless, significant differences were observed, suggesting that assessment of ocular blood-flow may represent an important diagnostic method in PE.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.