Changes in Macular Microvascular Structure in Macular Edema Secondary to Branch Retinal Vein Occlusion Treated with Antivascular Endothelial Growth Factor for One Year

Widefield, Swept-Source Optical Coherence Tomography Angiography Metrics as Predictors of Anti-VEGF Treatment in Retinal Vein Occlusions

BACKGROUND AND OBJECTIVE

Our objective was to assess baseline widefield swept-source optical coherence tomography angiography (WF SSOCTA) microvascular metrics as predictors for the number of anti-vascular endothelial growth factor (VEGF) injections and visual acuity (VA) at 12-months follow-up in patients with retinal vein occlusion (RVO).

PATIENTS AND METHODS

This was a prospective study including 49 RVO eyes from 49 patients who had not received an anti-VEGF injection for at least 3 months prior to imaging. Microvascular metrics from 6×6-mm and 12×12-mm angiograms were assessed using linear regression models, adjusting for age.

RESULTS

Reductions in the vessel density (VD) and vessel skeletonized density (VSD) vascular metrics were associated both with a higher number of anti-VEGF injections at all follow-up time points and reduced VA 12 months after imaging in all RVO eyes.

CONCLUSIONS

WF SS-OCTA VD and VSD micro-vascular metrics at baseline can prognosticate VA and number of anti-VEGF injections required at 3, 6, and 12 months in RVO eyes. [Ophthalmic Surg Lasers Imaging Retina 2024;55:374-382.].

Application of optical coherence tomography angiography in the assessment of diabetic macular edema staging and laser photocoagulation efficacy

OBJECTIVE

This study aimed to analyze the effect of optical coherence tomography angiography (OCTA) on diabetic macular edema (DME) staging and assess the efficacy of laser photocoagulation.

METHODS

Eighty-six patients (141 eyes) with suspected DME who visited our hospital from August 2019 to March 2022 were selected and underwent fundus angiography and OCTA. The two examination methods were compared in terms of their efficacy in macular edema staging. Subsequently, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of OCTA in diagnosing DME were assessed using fundus angiography as the gold standard. In patients with clinically significant macular edema (CSME) treated with laser photocoagulation, the central concave non-perfused zone (FAZ), vascular density (VD), central macular retinal thickness (CRT), whole retinal blood flow density (FD-300), superficial capillary plexus (SCP), and deep capillary plexus (DCP) were measured using the OCTA 3 mm × 3 mm mode before treatment, at 3 months after treatment, and at 6 months after treatment. SCP, deep capillary plexus (DCP), blood flow density (VD), best corrected visual acuity (BCVA), and central retinal thickness (CRT) were recorded before treatment, 3 months after treatment, and 6 months after treatment. The correlation between BCVA and pre-treatment OCTA parameters at 6 months after treatment was analyzed using Pearson's correlation.

RESULTS

Fundus angiography was performed in 86 patients (141 eyes) with suspected DME. Of the 141 eyes, 44 had no leakage, 52 had diffuse edema, 40 had focal macular edema, and 5 had eyes ischemia. A total of 97 eyes showed CSME on fundus angiography. Using fundus angiography as the gold standard, OCTA exhibited a sensitivity of 97.94 %, a specificity of 63.64 %, and an accuracy of 87.23 % in diagnosing CSME. The Kappa value between OCTA and fundus angiography was 0.674. The receiver operating characteristic curve revealed that the area under the curve (AUC) of OCTA in diagnosing CSME was 0.808 (95 % confidence interval: 0.717-0.899). The BCVA was higher, while the CRT was lower in CSME patients at 3 and 6 months after treatment (P<0.05). No significant difference was observed in the OCTA parameters in CSME patients at 3 months after treatment compared with that before treatment (P>0.05). Similarly, no significant difference was found in the FD300 of CSME patients at 6 months after treatment compared with that before treatment (P>0.05). However, the FAZ area, DCP-VD (overall, central concave, and paracentral concave), and SCP-VD (overall, central concave, and paracentral concave) were higher in CSME patients at 6 months after treatment compared with that before treatment (P<0.05). Pearson's correlation showed that BCVA was positively correlated with pre-treatment FAZ area, DCP-VD, and SCP-VD (r>0, P<0.05), and negatively associated with CRT (r<0, P<0.05).

CONCLUSION

OCTA exhibited high sensitivity and specificity in diagnosis and staging DME. It adeptly captures the microvascular and visual changes in the central macular recess before and after laser photocoagulation therapy, which can quantitatively guide the follow-up treatment of DME.

Acute and subacute intraocular pressure and macular microvascular structure changes after intravitreal ranibizumab injection in eyes with branch retinal vein occlusion

PURPOSE

To investigate early changes in the intraocular pressure (IOP) and macular microvascular structure in eyes with branch retinal vein occlusion (BRVO) treated with intravitreal Ranibizumab injection.

METHODS

This study enrolled 30 patients (one eye per patient) who received intravitreal injections (IVI) of ranibizumab for macular edema secondary to BRVO. IOP were measured before, 30 min (min) and 1 month following IVI. Changes in macular microvascular structure were examined via assessment of foveal avascular zone (FAZ) parameters, vascular density (VD) of superficial vascular complex (SVC), and deep vascular complex (DVC) in whole macula, central fovea and parafovea area which were measured automatically by optical coherence tomography angiography (OCTA) on the same time as IOP examinations. Paired t test and Wilcoxon test were used to compare pre- and post-injection values. The correlation between IOP and OCTA findings was assessed.

RESULTS

IOP Measurements at 30 min post-IVI (17.91 ± 3.36 mmHg) increased significantly from baseline (15.07 ± 2.58 mmHg, p < 0.001), then became similar with baseline after 1 month (15.00 ± 3.16 mmHg, p = 0.925). 30 min past the injection, the parameters of VD of the SCP significantly decreased in comparison to baseline, then became similar with baseline after one month, while there were no significant changes in other OCTA parameters, including parameters of VD of the DCP and the FAZ. At 1 month after IVI, in comparison to baseline, no significant changes were observed in all of the OCTA parameters (P > 0.05). There were no significant correlations between IOP and OCTA findings no matter 30 min or 1 month post-IVI (P > 0.05).

CONCLUSIONS

Transient IOP elevation and decreased superficial macular capillary perfusion density were detected 30 min post-IVI, however, no potential continual macular microvascular damage was suspected.

Predicting OCT images of short-term response to anti-VEGF treatment for retinal vein occlusion using generative adversarial network

To generate and evaluate post-therapeutic optical coherence tomography (OCT) images based on pre-therapeutic images with generative adversarial network (GAN) to predict the short-term response of patients with retinal vein occlusion (RVO) to anti-vascular endothelial growth factor (anti-VEGF) therapy. Real-world imaging data were retrospectively collected from 1 May 2017, to 1 June 2021. A total of 515 pairs of pre-and post-therapeutic OCT images of patients with RVO were included in the training set, while 68 pre-and post-therapeutic OCT images were included in the validation set. A pix2pixHD method was adopted to predict post-therapeutic OCT images in RVO patients after anti-VEGF therapy. The quality and similarity of synthetic OCT images were evaluated by screening and evaluation experiments. We quantitatively and qualitatively assessed the prognostic accuracy of the synthetic post-therapeutic OCT images. The post-therapeutic OCT images generated by the pix2pixHD algorithm were comparable to the actual images in edema resorption response. Retinal specialists found most synthetic images (62/68) difficult to differentiate from the real ones. The mean absolute error (MAE) of the central macular thickness (CMT) between the synthetic and real OCT images was 26.33 ± 15.81 μm. There was no statistical difference in CMT between the synthetic and the real images. In this retrospective study, the application of the pix2pixHD algorithm objectively predicted the short-term response of each patient to anti-VEGF therapy based on OCT images with high accuracy, suggestive of its clinical value, especially for screening patients with relatively poor prognosis and potentially guiding clinical treatment. Importantly, our artificial intelligence-based prediction approach’s non-invasiveness, repeatability, and cost-effectiveness can improve compliance and follow-up management of this patient population.

Structural and Visual Changes in Branch Retinal Vein Occlusion Patients with Retinal Atrophy

Background

To study the changes of retinal vascular density (VD), retinal thickness (RT), and their correlations with visual acuity (VA) in branch retinal vein occlusion (BRVO) patients with retinal atrophy after resolution of macular oedema (MO).

Methods

This is a retrospective study consisting of 46 patients diagnosed with BRVO at Beijing Hospital from 2015 to 2019. Patients' 46 affected eyes and 39 fellow eyes were included. The affected eyes were further divided into the atrophy group and the nonatrophy group. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images obtained when MO completely resolved after treatment with ranibizumab were analyzed. We quantitatively measured foveal avascular zone (FAZ) parameters, the disruption extent of ellipsoid zone (EZ), RT, and VD of superficial vascular complex (SVC), and deep vascular complex (DVC) in central fovea and the minimal-VD quadrant. Paired t-tests, independent t-tests, Mann–Whitney U tests, Wilcoxon tests, Pearson correlation analyses, Spearman correlation analyses, and single and multiple linear regression models were adopted.

Results

Compared with nonatrophy eyes, the minimal-VD quadrantal (quadrantal for short) SVC-VD (25.76 ± 4.57% versus 36.21 ± 6.47%, P < 0.001) and quadrantal DVC-VD (27.72 (17.23) % versus 38.95 (11.05) %, P = 0.001) of atrophy eyes decreased significantly. Quadrantal SVC-VD and quadrantal DVC-VD were strongly correlated with quadrantal full RT (r = 0.763 and 0.698, both P < 0.001). The disruption length of EZ was significantly correlated with quadrantal full RT (r = −0.406, P = 0.005) and quadrantal SVC-VD (r = −0.298, P = 0.044). In multiple linear regression analysis, the disruption length of EZ and VA before treatment and age showed significant correlations with VA with complete resolution of MO (P = 0.020,  0.033,  and 0.002).

Conclusions

The retinal VD on the affected area correlates well with the corresponding full RT when BRVO-MO completely resolves, suggesting that VD may predict the final RT. Severe decrease in VD may result in retinal atrophy, which may cause VA loss indirectly with the intermediate influencing factor of EZ defects.

Wide-field swept-source OCT angiography of the periarterial capillary-free zone before and after anti-VEGF therapy for branch retinal vein occlusion

BACKGROUND

The aim of the study was to investigate the changes in the periarterial capillary-free zone (paCFZ) after anti-vascular endothelial growth factor (VEGF) therapy in patients with branch retinal vein occlusion (BRVO) by wide-field swept-source optical coherence tomography angiography (SS-OCTA) and assess their associations with clinical outcomes.

METHODS

In this retrospective observational study of 54 treatment-naïve BRVO patients with macular edema, we reviewed the findings of 12 × 12 mm² SS-OCTA at baseline, 3, 6, and 12 months after intravitreal ranibizumab injections. The paCFZ and major retinal artery areas were measured on SS-OCTA images. The paCFZ area to artery area (P/A) ratio was calculated.

RESULTS

The paCFZ areas and P/A ratios of first- and second-order arteries were significantly greater in BRVO eyes than in contralateral eyes (all P < 0.01), but there were no differences in the first- and second-order artery areas (P = 0.20 and 0.25, respectively). The paCFZ areas and P/A ratios decreased significantly at 3, 6, and 12 months after anti-VEGF therapy (all P < 0.01). The baseline P/A ratio was significantly correlated with the baseline best-corrected visual acuity (BCVA), central retinal thickness, and their improvements at 3, 6, and 12 months (all P < 0.05). Baseline BCVA and P/A ratios of first- and second-order arteries were independently associated with the final BCVA in multivariate linear regression.

CONCLUSIONS

Wide-field SS-OCTA shows that anti-VEGF therapy can lead to a significant improvement in the paCFZ parameters in BRVO. Smaller baseline P/A ratios on SS-OCTA tend to predict better visual outcomes at 12 months after anti-VEGF therapy.

The impact of laboratory findings and optical coherence tomography biomarkers on response to intravitreal anti-VEGF treatment in patients with retinal vein occlusion

AIMS

To investigate potential laboratory and imaging biomarkers as treatment response predictors to intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents in patients with retinal vein occlusion (RVO).

METHODS

Participants in this prospective study were 53 patients with treatment naïve macular edema secondary to RVO, treated with intravitreal anti-VEGF agents and followed-up for 12 months. At baseline, all participants underwent best-corrected visual acuity measurement, dilated fundoscopy, optical coherence tomography and fluorescein angiography (FFA), while full blood count and biochemical analysis of various parameters was also performed. At month 12, treatment response was examined and classified as "favorable" or "non-response". Potential associations between laboratory/imaging biomarkers and treatment response were assessed.

RESULTS

Univariate analysis showed that "favorable" response at month 12 after initiation of anti-VEGF treatment was correlated with baseline central subfield thickness (CST) < 464 μm (p < 0.001), absence of subretinal fluid (p = 0.004), absence of hyperreflective foci (HF) (p = 0.004), intact ellipsoid zone (EZ) and external limiting membrane (ELM) (p < 0.001 and p = 0.001, respectively), absence of epiretinal membrane (ERM) (p = 0.020) and absence of macular ischemia on FFA (p < 0.001), while increased monocytes-to-lymphocytes ratio was also associated with "favorable" treatment response (p = 0.010). All other laboratory parameters did not reach statistical significance. However, at the multivariate analysis, EZ and ELM status, HF, macular ischemia and monocytes-to-lymphocytes ratio were found to be independent predictors of treatment response.

CONCLUSIONS

Intact EZ and ELM, absence of HF, absence of macular ischemia and increased monocytes-to-lymphocytes ratio at baseline can predict "favorable" treatment response in patients with treatment naïve macular edema secondary to RVO.