Vascular imaging findings in retinopathy of prematurity

Retinopathy of prematurity (ROP) is a vascular disease among preterm infants involving incomplete or abnormal retinal vascularization and is a leading cause of preventable blindness globally. Measurements of ocular blood flow originating from a variety of imaging modalities, including colour Doppler imaging (CDI), fluorescein angiography (FA) and ocular coherence tomography angiography (OCTA), have been associated with changes in ROP patients. Herein, we discuss and summarize the relevant current literature on vascular imaging and ROP reviewed through December 2022. Differences in vascular imaging parameters between ROP patients and healthy controls are reviewed and summarized. The available data identify significantly increased peak systolic velocity (PSV) in the central retinal artery and ophthalmic artery as measured by CDI, increased vascular tortuosity as measured by FA, smaller foveal avascular zone (FAZ) as measured by FA and OCTA, and increased foveal vessel density (VD) and reduced parafoveal VD as measured by OCTA in ROP patients compared with controls. None of the above findings appear to reliably correlate with visual acuity. The studies currently available, however, are inconclusive and lack robust longitudinal data. Vascular imaging demonstrates the potential to aid in the diagnosis, management and monitoring of ROP, alongside retinal examination via indirect ophthalmoscopy and fundus photography.

Retinal blood flow velocities in infants with retinopathy of prematurity after intravitreal administration of bevacizumab

BACKGROUND/OBJECTIVES

Progression of retinopathy of prematurity (ROP) is associated with increased retinal blood flow velocities. We investigated changes of central retinal arterial and venous blood flow after intravitreal administration of bevacizumab.

SUBJECTS/METHODS

Prospective observational study using serial ultrasound Doppler imaging in preterm infants with bevacizumab-treated ROP. Eyes were examined 1 [0-2] days before injection (median [interquartile range]), and at three time points after injection (1 [1-2] days, 6 [3-8] days, and 17 [9-28] days). Preterm infants with ROP stage 2 displaying spontaneous regression served as controls.

RESULTS

In 21 eyes of 12 infants with bevacizumab-treated ROP, peak arterial systolic velocity declined from 13.6 [11.0-16.3] cm/s prior to intravitreal bevacizumab to 11.2 [9.4-13.9] cm/s, 10.6 [9.2-13.3] cm/s and 9.3 [8.2-11.0] cm/s at discharge (p  =  .002). There was also a decline of the arterial velocity time integral (from 3.1 [2.3-3.9] cm to 2.9 [2.4-3.5], 2.7 [2.3-3.2] cm and 2.2 [2.0-2.7], p  =  .021) and mean velocity in the central retinal vein (from 4.5 [3.6-5.8] cm/s to 3.7 [2.6-4.1] cm/s, 3.5 [3.0-4.3] cm/s, and 3.2 [2.8-4.6] cm/s, p  =  .012). Arterial end-diastolic velocity and resistance index remained unchanged. Blood flow velocities in bevacizumab-treated eyes examined before injection were significantly higher than those measured in untreated eyes that ultimately showed spontaneous regression of ROP. Sequential examinations in these controls did not reveal any declines of retinal blood flow velocities.

CONCLUSION

Increased retinal arterial and venous blood flow velocities in infants with threshold ROP decline following intravitreal bevacizumab injection.

Intravitreal bevacizumab treatment reduces ocular blood flow in retinopathy of prematurity: a four-case report

PURPOSE

To evaluate the relationship between ocular blood flow, expressed as mean blur rate (MBR) by laser speckle flowgraphy, and intravitreal bevacizumab (IVB) therapy in neonates with retinopathy of prematurity (ROP).

METHODS

This was a case series study of 4 neonates with ROP under sedation before and after IVB and evaluated 8 eyes, in which the circulation could be measured three times consecutively. We performed optic nerve head blood flow measurement and fluorescein angiography (FA) before and 1 week after treatment. Blood flow was analyzed separately for MBR-A (mean of all values), MBR-V (vessel mean), and MBR-T (tissue mean). Comparisons between the MBR (-A, -V, -T), body weight, and other systemic and ocular parameters before and after treatment were performed using a paired t test.

RESULTS

The MBR values after IVB were lower than the pre-treatment values in all cases. All eyes showed leakage at neovascularization on FA before treatment. Although leakage improved 1 week after treatment, the neovascularization did not completely regress.

CONCLUSIONS

IVB improves vein dilation and artery tortuosity, while reducing ocular blood flow in neonates with ROP. We suggest that neovascularization might not be involved in reducing ocular blood flow in the early stage of IVB treatment.

Decreased ocular blood flow after photocoagulation therapy in neonatal retinopathy of prematurity

PURPOSE

To evaluate the relationships between optic nerve head blood flow, expressed as mean blur rate (MBR) measured by laser speckle flowgraphy (LSFG), and photocoagulation therapy in neonates with retinopathy of prematurity (ROP).

STUDY DESIGN

Case series study.

METHODS

We studied 5 ROP neonates either during sleep or under sedation both before and after photocoagulation, and evaluated 8 eyes in which the circulation could be measured three times consecutively. Correlations between the MBR-A (mean of all values), MBR-V (vessel mean) and MBR-T (tissue mean) and postmenstrual age were evaluated using Spearman's rank correlation coefficient. In addition, correlations between the relative MBR (-A, -V, -T) value and number of photocoagulation burns and the NV score were evaluated. Differences between post-treatment MBR in ROP subjects and normal neonates' MBR were estimated using analysis of covariance (ANCoVA), with adjustment for postmenstrual age.

RESULTS

The relative MBR (-A, -V, -T) values after photocoagulation were 69.6 ± 16.0%, 66.7 ± 17.0% and 74.3 ± 14.6%, respectively. Postmenstrual age was significantly correlated with post-treatment MBR-A (r = 0.83, p = 0.0101), MBR-V (r = 0.85, p = 0.007) and MBR-T (r = 0.76, p = 0.0282). The relative MBR-T value was significantly correlated with the number of photocoagulation burns (r = -0.75, p = 0.033) and NV score (r = -0.72, p = 0.0437). The ANCoVA results showed no significant difference between post-treatment MBR and normal neonates' MBR.

CONCLUSIONS

Photocoagulation improved the dilation of veins and tortuosity of arteries and reduced ocular blood flow in ROP subjects. Since the post-treatment MBR was not different from a normal neonate's MBR, it is suggested that the pre-treatment MBR was higher in severe ROP cases.

Effect of Intravitreal Aflibercept on Central Retinal Arterial Blood Flow in Type 1 Retinopathy of Prematurity

Purpose

To evaluate the blood flow changes of the central retinal artery measured with color Doppler imaging (CDI) in infants receiving intravitreal aflibercept (IVA) for treatment of type 1 retinopathy of prematurity (ROP).

Methods

Patients with type 1 ROP were assessed prospectively by CDI following IVA. Color Doppler imaging was used to measure the peak systolic velocity, end diastolic velocity (EDV), pulsatility index (PI), and resistivity index (RI) of the central retinal artery (CRA) before IVA injection and 1 hour, 1 week, and 1 month after injection.

Results

A total of 29 eyes of 15 infants were included in this study. The mean gestational age at birth was 28.62 ± 2.48 weeks and the mean birthweight was 1,198.62 ± 348.99 g. All treated eyes showed complete regression of ROP and peripheral retinal vascularization continued. Measurements of EDV-CRA, RI-CRA, and PI-CRA showed significant changes after IVA treatment.

Conclusions

This study showed that IVA is an effective treatment for type 1 ROP. After IVA treatment, vascular resistance increases, ocular blood flow decreases, and changes in hemodynamic parameters of CRA may remain for a month. Further studies are needed to evaluate the effect of anti-vascular endothelial growth factor agents on ocular hemodynamics in infants with ROP.

A Change in Ocular Circulation after Photocoagulation for Retinopathy of Prematurity in a Neonate

Background

The dilation of veins and tortuosity of arteries that occur in retinopathy of prematurity (ROP) are improved by therapy, and thus posttherapy changes in ocular circulation are also conceivable. We report a case of ROP in which we were able to measure the ocular circulation before and after photocoagulation therapy, using a laser speckle flowgraphy (LSFG) system that is modified for neonates.

Case Report

A female infant was born at 25 weeks' gestation with a birth weight of 808 g. We performed photocoagulation in both eyes at age 15 weeks, and we measured the ocular circulation with the “LSFG-baby” system before and at 12 weeks after the photocoagulation treatment. We also measured the mean blur rate (MBR) in the optic nerve head (ONH) and the relative flow volume (RFV) in the retinal vessels, and we examined the change rates from before to after treatment. The changing rate of the MBR-A (the mean of all values) in the ONH in the right and left eyes was 76.5 and 98.5%, respectively. The vascular RFV in the severe dilation and tortuosity quadrant also tended to decrease.

Conclusions

Photocoagulation improved the dilation of veins and tortuosity of arteries and reduced the ocular blood flow in this neonate with ROP. The LSFG-baby system effectively and directly revealed the optic nerve and retinal blood vessels.