Preoperative intravitreal bevacizumab use as an adjuvant to diabetic vitrectomy: histopathologic findings and clinical implications

The impact of Vitreo-Macular interface abnormalities on the response to Anti-VEGF therapy for centre involving diabetic macular oedema

BACKGROUND

The influence of Vitreomacular Interface Abnormalities (VMIA) such as Epiretinal Membrane (ERM) and/or vitreomacular traction (VMT) on the response of patients with Centre Involving Diabetic Macular Edema (CIDME) to standard of care Anti-VEGF medications is under-researched. The aims of this study were: 1) To determine the incidence of VMIA at baseline and 12 months amongst treatment naive patients commencing anti-VEGF treatment 2) To compare the response to Anti-VEGF medications at 3 monthly intervals for 12 months in a large cohort of patients with and without VMIA on their baseline OCT scan. Response was determined in terms of: number of injections, central macular thickness and visual acuity.

METHODS

A retrospective case notes review of treatment naïve patients with newly diagnosed CIDME. Included patients had been commenced on intravitreal Anti-VEGF injections (ranibizumab or aflibercept) at a single centre. Inclusion criteria were: treatment naïve DME patients with a CMT of 400μ or more receiving anti-VEGF treatment with at least 12 months follow up and in whom macular OCT scans and visual acuity (VA) measurements were available within two weeks of baseline, 3, 6, 9 and 12 months. Exclusion criteria included: previous intravitreal therapy, previous vitrectomy, cataract surgery during the follow-up period, concurrent eye conditions affecting vision or CMT.

RESULTS

119 eyes met the inclusion criteria and underwent analysis. Groups were comparable in their baseline demographics. Baseline CMT measurements were comparable at baseline (417μ and 430μ in the No-VMIA and VMIA groups respectively) and improved to approximately 300μ in both groups. From 6 months CMT continued to improve in the no-VMIA while progressively deteriorating in the VMIA group. Change in CMT was statistically different at 12 months between the 2 groups (108μ and 79μ, p= 0.04). There was a mean of 7 injections after 12 months.

CONCLUSION

Our study has shown a 46% incidence of VMIA amongst patients newly diagnosed with centre involving DME undergoing treatment with anti-VEGF injections. We have also demonstrated a significant difference in CMT and VA response to anti-VEGF treatment in patients with and without VMIA. Initial response was similar between the 2 groups up until 6 months. From 6 to 12 months significant differences in treatment response emerged. Differences in clinical response between patients with and without VMIA may help guide further prospective controlled studies and optimise treatment strategies.

Anti-vascular endothelial growth factors in combination with vitrectomy for complications of proliferative diabetic retinopathy

BACKGROUND

Vitrectomy is an established treatment for the complications of proliferative diabetic retinopathy (PDR). However, a number of complications can occur during and after vitrectomy for PDR. These include bleeding and the creation of retinal holes during surgery, and bleeding, retinal detachment and scar tissue on the retina after surgery. These complications can limit vision, require further surgery and delay recovery. The use of anti-vascular endothelial growth factor (anti-VEGF) agents injected into the eye before surgery has been proposed to reduce the occurrence of these complications. Anti-VEGF agents can reduce the amount and vascularity of abnormal new vessels associated with PDR, facilitating their dissection during surgery, reducing intra- and postoperative bleeding, and potentially improving outcomes.

OBJECTIVES

To assess the effects of perioperative anti-VEGF use on the outcomes of vitrectomy for the treatment of complications for proliferative diabetic retinopathy (PDR).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 6); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 22 June 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that looked at the use of anti-VEGFs and the incidence of complications in people undergoing vitrectomy for PDR.   DATA COLLECTION AND ANALYSIS: Two review authors independently assessed and extracted the data. We used the standard methodological procedures expected by Cochrane. The critical outcomes of the review were the mean difference in best corrected visual acuity (BCVA) between study arms at six (± three) months after the primary vitrectomy, the incidence of early postoperative vitreous cavity haemorrhage (POVCH, within four weeks postoperatively), the incidence of late POVCH (occurring more than four weeks postoperatively), the incidence of revision surgery for POVCH within six months, the incidence of revision surgery for recurrent traction/macular pucker of any type and/or rhegmatogenous retinal detachment within six months and vision-related quality of life (VRQOL) measures. Important outcomes included the proportion of people with a visual acuity of counting fingers (1.8 logMAR or worse), the number of operative retinal breaks reported and the frequency of silicone oil tamponade required at time of surgery.

MAIN RESULTS

The current review includes 28 RCTs that looked at the pre- or intraoperative use of intravitreal anti-VEGFs to improve the outcomes of pars plana vitrectomy for complications of PDR. The studies were conducted in a variety of countries (11 from China, three from Iran, two from Italy, two from Mexico and the remaining studies from South Korea, the UK, Egypt, Brazil, Japan, Canada, the USA, Indonesia and Pakistan). The inclusion criteria for entry into the studies were the well-recognised complications of proliferative retinopathy: non-clearing vitreous haemorrhage, tractional retinal detachment involving the macula or combined tractional rhegmatogenous detachment. The included studies randomised a total of 1914 eyes.  We identified methodological issues in all of the included studies. Risk of bias was highest for masking of participants and investigators, and a number of studies were unclear when describing randomisation methods and sequence allocation. Participants receiving intravitreal anti-VEGF in addition to pars plana vitrectomy achieved better BCVA at six months compared to people undergoing vitrectomy alone (mean difference (MD) -0.25 logMAR, 95% confidence interval (CI) -0.39 to -0.11; 13 studies, 699 eyes; low-certainty evidence). Pre- or intraoperative anti-VEGF reduced the incidence of early POVCH (12% versus 31%, risk ratio (RR) 0.44, 95% CI 0.34 to 0.58; 14 studies, 1038 eyes; moderate-certainty evidence). Perioperative anti-VEGF use was also associated with a reduction in the incidence of late POVCH (10% versus 23%, RR 0.47, 95% CI 0.30 to 0.74; 11 studies, 579 eyes; high-certainty evidence). The need for revision surgery for POVCH occurred less frequently in the anti-VEGF group compared with control, but the confidence intervals were wide and compatible with no effect (4% versus 13%, RR 0.44, 95% CI 0.15 to 1.28; 4 studies 207 eyes; moderate-certainty evidence). Similar imprecisely measured effects were seen for revision surgery for rhegmatogenous retinal detachment (5% versus 11%, RR 0.50, 95% CI 0.15 to 1.66; 4 studies, 145 eyes; low-certainty evidence).  Anti-VEGFs reduce the incidence of intraoperative retinal breaks (12% versus 31%, RR 0.37, 95% CI 0.24 to 0.59; 12 studies, 915 eyes; high-certainty evidence) and the need for silicone oil (19% versus 41%, RR 0.46, 95% CI 0.27 to 0.80; 10 studies, 591 eyes; very low-certainty evidence). No data were available on quality of life outcomes or the proportion of participants with visual acuity of counting fingers or worse.

AUTHORS' CONCLUSIONS

The perioperative use of anti-VEGF reduces the risk of late POVCH, probably results in lower early POVCH risk and may improve visual outcomes. It also reduces the incidence of intraoperative retinal breaks. The evidence is very uncertain about its effect on the need for silicone oil tamponade. The reported complications from its use appear to be low. Agreement on variables included and outcome standardisation is required in trials studying vitrectomy for PDR.

Advances in Vitreoretinal Surgery

Advances in vitreoretinal surgery provide greater safety, efficacy, and reliability in the management of the several vitreoretinal diseases that benefit from surgical treatment. The advances are divided into the following topics: scleral buckling using chandelier illumination guided by non-contact visualization systems; sclerotomy/valved trocar diameters; posterior vitrectomy systems and ergonomic vitrectomy probes; chromovitrectomy; vitreous substitutes; intraoperative visualization systems including three-dimensional technology, systems for intraoperative optical coherence tomography, new instrumentation in vitreoretinal surgery, anti-VEGF injection before vitrectomy and in eyes with proliferative diabetic retinopathy, and new surgical techniques; endoscopic surgery; the management of subretinal hemorrhages; gene therapy; alternative techniques for refractory macular hole; perspectives for stem cell therapy and the prevention of proliferative vitreoretinopathy; and, finally, the Port Delivery System. The main objective of this review is to update the reader on the latest changes in vitreoretinal surgery and to provide an understanding of how each has impacted the improvement of surgical outcomes.

Monitoring intraocular proangiogenic and profibrotic cytokines within 7 days after adjunctive anti-vascular endothelial growth factor therapy for proliferative diabetic retinopathy

PURPOSE

To monitor the intraocular proangiogenic and profibrotic cytokine profiles within 7 days after intravitreous injection of conbercept (IVC) for patients with proliferative diabetic retinopathy (PDR).

METHODS

This prospective, randomized controlled, consecutive, comparative study included 157 eyes with PDR. Participant eyes underwent sham IVC or IVC and subsequent vitrectomy at days 2, 3, 4, 5, 6, 7 postinjection. The intraocular cytokines profiles were measured using beaded assay methods.

RESULTS

After IVC, the vascular endothelial growth factor (VEGF)-A level in PDR vitreous decreased rapidly by approximately 10 times at day 2 (p = 0.00001) and kept at a low level at days 3, 4, 5, 6, 7 (p < 0.001, each compared with IVC-sham group). Similar tendency of the change in VEGF-A was observed in aqueous humour. The level of placenta growth factor (PIGF) in aqueous humour decreased 2 days after IVC whereas returned to baseline level after 5 days. The vitreous profibrotic cytokines, tissue growth factor (TGF)-β1, TGF-β2, TGF-β3 and connective tissue growth factor did not increase after IVC in each group.

CONCLUSION

We observed a remarkable and rapid decrease in intraocular VEGF-A, temporal decrease in PIGF from day 2 to day 4, increase in VEGF-C and VEGF-D from day 2 onwards, but no profibrotic switch in PDR eyes after IVC. The findings might suggest that ideal vitrectomy timing might be around 3 days after IVC.

Single-Cell Transcriptomics Reveals Novel Role of Microglia in Fibrovascular Membrane of Proliferative Diabetic Retinopathy

Vitreous fibrovascular membranes (FVMs), the hallmark of proliferative diabetic retinopathy (PDR), cause retinal hemorrhage, detachment, and eventually blindness. However, little is known about the pathophysiology of FVM. In this study, we used single-cell RNA sequencing on surgically harvested PDR-FVMs and generated a comprehensive cell atlas of FVM. Eight cellular compositions were identified, with microglia as the major cell population. We identified a GPNMB+ subpopulation of microglia, which presented both profibrotic and fibrogenic properties. Pseudotime analysis further revealed the profibrotic microglia was uniquely differentiated from retina-resident microglia and expanded in the PDR setting. Ligand-receptor interactions between the profibrotic microglia and cytokines upregulated in PDR vitreous implicated the involvement of several pathways, including CCR5, IFNGR1, and CD44 signaling, in the microglial activation within the PDR microenvironment. Collectively, our description of the novel microglia phenotypes in PDR-FVM may offer new insight into the cellular and molecular mechanism underlying the pathogenesis of DR, as well as potential signaling pathways amenable to disease-specific intervention.

Intravitreal conbercept as an adjuvant in vitrectomy for proliferative diabetic retinopathy: a meta-analysis of randomised controlled trials

PURPOSE

To evaluate the efficacy of intravitreal conbercept (IVC) in pars plana vitrectomy (PPV) for patients with proliferative diabetic retinopathy (PDR).

METHODS

A meta-analysis of randomized control trials (RCTs) using online databases was performed. The intraoperative outcome measures were the incidence of intraoperative bleeding and endodiathermy application, and the mean surgical time. The postoperative outcome measures were mean change in best-corrected visual acuity (BCVA) from baseline, postoperative vitreous clear-up time and incidence of recurrent vitreous hemorrhage (VH).

RESULTS

Eight RCTs were selected for meta-analysis. They included 409 eyes (215 eyes in IVC group and 194 eyes in no conbercept group). Preoperative IVC application was associated with less intraoperative bleeding and endodiathermy applications (RR = 0.34, 95% CI, 0.23-0.50, P < 0.00001, and RR = 0.26, 95% CI, 0.12-0.56, P = 0.0005) compared to no conbercept. It also shortened surgical time (WMD = -15.87, 95% CI, -22.04 to -9.69, P < 0.00001). In addition, preoperative or intraoperative IVC achieved better BCVA outcome (WMD = -0.37, 95% CI, -0.62 to -0.13, P = 0.003), shorter vitreous clear-up time postoperatively (WMD = -5.44, 95% CI, -6.31 to -4.57, P < 0.00001) and a lower rate of VH recurrence (RR = 0.45, 95% CI, 0.22-0.91, P = 0.03).

CONCLUSION

IVC is an effective adjuvant in PPV for PDR, with better intraoperative and postoperative outcomes.

Comparison of before versus after intravitreal bevacizumab injection, growth factor levels and fibrotic markers in vitreous samples from patients with proliferative diabetic retinopathy

PURPOSE

In diabetic retinopathy patients, intravitreal bevacizumab (IVB) injections are widely used to facilitate dissection of retinal fibrovascular membranes during surgery, reduce the rate of perioperative hemorrhage, and prevent recurrent neovascularization. Previous studies have shown that IVB may worsen fibrosis and thereby impair vision. The aim of this study was to determine which markers are associated with fibrosis.

METHODS

Twenty-three patients with proliferative diabetic retinopathy (PDR) underwent pars plana vitrectomy (PPV) with IVB pretreatment for intraocular hemorrhage (IOH) and/or tractional retinal detachment (TRD). Vitreous samples were obtained at the time of IVB injection and again at the beginning of PPV, about a week later. Using Western blot analysis, the concentrations of vascular endothelial growth factor (VEGF), placental growth factor (PIGF), insulin like growth factor-1 (IGF-1), angiogenin-1 (Ang-1), and vascular endothelial cadherin (VE-cadherin) were measured in vitreous samples.

RESULTS

After treatment with IVB, VEGF, PIGF, and VE-cadherin concentrations in the vitreous significantly decreased (p < 0.001, p < 0.001, and p = 0.001, respectively), whereas the concentrations of IGF-1 increased (p = 0.001). There were no significant changes in Ang-1 concentrations in the vitreous after IVB injection (p = 0.732). There were no statistically significant differences in VEGF-A, PIGF, VE-cadherin, IGF, and Ang-1 levels before and after IVB injection when the IOH and TRD groups underwent subgroup analysis (p = 0.696, p = 0.516, p = 0.498, p = 0.188, and p = 0.243, respectively).

CONCLUSION

The levels of VEGF and other cytokines changed in the vitreous after IVB. The adverse effects associated with IVB, such as fibrosis, may result from modulation of vitreous cytokine concentrations. In the treatment of PDR, drugs that optimize the effects of PIGF, IGF-1, and VE-cadherin to reduce these side effects may be useful.

Intravitreal bevacizumab prior to vitrectomy for proliferative diabetic retinopathy: a systematic review

Background:

Diabetic retinopathy is a leading cause of visual loss in the working population. Pars plana vitrectomy has become the mainstream treatment option for severe proliferative diabetic retinopathy (PDR) associated with significant vitreous haemorrhage and/or tractional retinal detachment. Despite the advances in surgical equipment, diabetic vitrectomy remains a challenging operation, requiring advanced microsurgical skills, especially in the presence of tractional retinal detachment. Preoperative intravitreal bevacizumab has been widely employed as an adjuvant to ease surgical difficulty and improve postoperative prognosis.Aims: This study aims to assess the effectiveness of preoperative intravitreal bevacizumab in reducing intraoperative complications and improving postoperative outcomes in patients undergoing vitrectomy for the complications of PDR.

Methods:

A literature search was conducted using the PubMed, Cochrane, and ClinicalTrials.gov databases to identify all related studies published before 31/10/2020. Prespecified outcome measures were operation time, intraoperative iatrogenic retinal breaks, best-corrected visual acuity in the last follow-up visit, the presence of any postoperative vitreous haemorrhage and the need to re-operate. Evidence synthesis was performed using Fixed or Random Effects models, depending on the heterogeneity of the included studies. Heterogeneity was assessed using Q-statistic and I². Additional meta-regression models, subgroup analyses and sensitivity analyses were performed as appropriate.

Results:

Thirteen randomized control trials, with a total of 688 eyes were included in this review. Comparison of the intraoperative data showed that bevacizumab reduced operation time (p < 0.001), minimized iatrogenic retinal breaks (p < 0.001), provided better long-term visual acuity outcomes (p = 0.005), and prevented vitreous haemorrhage (p < 0.001) and the need for reoperation (p = 0.001 < 0.05). Findings were strongly corroborated by additional sensitivity and subgroup analyses.

Conclusion:

Preoperative administration of bevacizumab is effective in reducing intraoperative complications and improving the postoperative prognosis of diabetic vitrectomy.

PROSPERO registration number: CRD42021219280

Analysis of Predisposing Clinical Features for Worsening Traction After Treatment of Familial Exudative Vitreoretinopathy in Children

PURPOSE

To determine the incidence of worsening vitreoretinal traction after laser treatment for familial exudative vitreoretinopathy (FEVR) and to determine whether any baseline clinical features are associated with worsening.

DESIGN

Retrospective cohort comparison study in a university tertiary referral center.

METHODS

All patients 0-21 years of age treated with laser from January 1, 2001, to June 1, 2018, were studied. Worsening traction after treatment was defined as the occurrence within 6 months of worsening or development of tractional retinal detachment, folds, dragging, breaks, rhegmatogenous detachment, or worsening tractional membranes. Comparisons of baseline features between groups with and without worsening were performed to determine features associated with higher risk.

RESULTS

A total of 46 eyes from 28 patients met inclusion criteria. Of the 46 eyes, 6 (13%) had worsening after treatment. There were no significant differences in age or other baseline demographics between the cohorts with and those without worsening traction. The presence of proliferative tissue in contact with the lens was found in 2 of 6 patients with worsening compared to 1 of 40 (3%) without worsening (P = .04). Mean follow-up was 57.8 months (range, 6.6-134 months). At the 6-month follow-up, median logMAR visual acuity in the cohorts with and without worsening was 1.7 (Snellen 20/1002; n = 5) and 0.24 (Snellen 20/35; n = 16), respectively.

CONCLUSIONS

Laser treatment resulted in worsening traction in a substantial proportion of eyes with FEVR. Children with proliferative tissue in contact with the lens may be at higher risk of worsening after laser. Potential measures to reduce risk will require further study to establish efficacy.

The incidence and risk factors of neovascular glaucoma secondary to proliferative diabetic retinopathy after vitrectomy

OBJECTIVE

The incidence and risk factors of neovascular glaucoma (NVG) secondary proliferative diabetic retinopathy (PDR) after pars plana vitrectomy (PPV) are unclear and reports in the published literature are inconsistent. Therefore, a systematic review and meta-analysis were conducted to clarify the risk factors associated with neovascular glaucoma.

METHODS

PubMed, Embase, and The Cochrane Library were systematically searched without language limitations for studies related to NVG after PPV in PDR patients. We used R software to fit the correlation between incidence and the date of publication for studies and performed a Spearman analysis. For binary and continuous variables, the odds ratios (ORs) with 95% confidence intervals (CIs) were pooled, respectively, using Review Manager 5.3 (The Cochrane Collaboration).

RESULTS

Twenty-six studies with 5161 patients were included in our meta-analysis. The overall pooled incidence of NVG after PPV in PDR patients was 6% (95% CI, 0.05-0.07, p-value < 0.00001). Pooled estimates indicated a positive correlation for NVG after PPV in PDR patients with higher baseline IOP (OR, 1.26; 95%CI,0.56-1.95, p-value = 0.0004), preoperative iris neovascularization (INV) (OR, 5.66; 95% CI, 2.10-15.23, p-value = 0.0006), preoperative or intraoperative combined cataract surgery (OR, 2.00; 95% CI, 1.15-3.46, p-value = 0.01), postoperative vitreous hemorrhage (VH) (OR, 3.53; 95% CI, 1.63-7.66, p-value = 0.001), and a negative correlation with age (OR, -2.90; 95%CI, -5.00 to -0.81, p-value < 0.007).

CONCLUSION

Our systematic review and meta-analysis indicated that the main risk factors for NVG after PPV in PDR patients included higher baseline IOP, preoperative INV, preoperative or intraoperative combined cataract surgery, postoperative VH, and was negatively correlated with age.

Modulating EGFR-MTORC1-autophagy as a potential therapy for persistent fetal vasculature (PFV) disease

Persistent fetal vasculature (PFV) is a human disease that results from failure of the fetal vasculature to regress normally. The regulatory mechanisms responsible for fetal vascular regression remain obscure, as does the underlying cause of regression failure. However, there are a few animal models that mimic the clinical manifestations of human PFV, which can be used to study different aspects of the disease. One such model is the Nuc1 rat model that arose from a spontaneous mutation in the Cryba1 (crystallin, beta 1) gene and exhibits complete failure of the hyaloid vasculature to regress. Our studies with the Nuc1 rat indicate that macroautophagy/autophagy, a process in eukaryotic cells for degrading dysfunctional components to ensure cellular homeostasis, is severely impaired in Nuc1 ocular astrocytes. Further, we show that CRYBA1 interacts with EGFR (epidermal growth factor receptor) and that loss of this interaction in Nuc1 astrocytes increases EGFR levels. Moreover, our data also show a reduction in EGFR degradation in Nuc1 astrocytes compared to control cells that leads to over-activation of the mechanistic target of rapamycin kinase complex 1 (MTORC1) pathway. The impaired EGFR-MTORC1-autophagy signaling in Nuc1 astrocytes triggers abnormal proliferation and migration. The abnormally migrating astrocytes ensheath the hyaloid artery, contributing to the pathogenesis of PFV in Nuc1, by adversely affecting the vascular remodeling processes essential to regression of the fetal vasculature. Herein, we demonstrate in vivo that gefitinib (EGFR inhibitor) can rescue the PFV phenotype in Nuc1 and may serve as a novel therapy for PFV disease by modulating the EGFR-MTORC1-autophagy pathway.

ABBREVIATIONS

ACTB: actin, beta; CCND3: cyclin 3; CDK6: cyclin-dependent kinase 6; CHQ: chloroquine; COL4A1: collagen, type IV, alpha 1; CRYBA1: crystallin, beta A1; DAPI: 4'6-diamino-2-phenylindole; EGFR: epidermal growth factor receptor; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFAP: glial fibrillary growth factor; KDR: kinase insert domain protein receptor; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MKI67: antigen identified by monoclonal antibody Ki 67; MTORC1: mechanistic target of rapamycin kinase complex 1; PARP: poly (ADP-ribose) polymerase family; PCNA: proliferating cell nuclear antigen; PFV: persistent fetal vasculature; PHPV: persistent hyperplastic primary vitreous; RPE: retinal pigmented epithelium; RPS6: ribosomal protein S6; RPS6KB1: ribosomal protein S6 kinase, polypeptide 1; SQSTM1/p62: sequestome 1; TUBB: tubulin, beta; VCL: vinculin; VEGFA: vascular endothelial growth factor A; WT: wild type.

APOPTOSIS AND ANGIOFIBROSIS IN DIABETIC TRACTIONAL MEMBRANES AFTER VASCULAR ENDOTHELIAL GROWTH FACTOR INHIBITION: Results of a Prospective Trial. Report No. 2

PURPOSE

We sought to characterize the angiofibrotic and apoptotic effects of vascular endothelial growth factor (VEGF)-inhibition on fibrovascular epiretinal membranes in eyes with traction retinal detachment because of proliferative diabetic retinopathy.

METHODS

Membranes were excised from 20 eyes of 19 patients (10 randomized to intravitreal bevacizumab, 10 controls) at vitrectomy. Membranes were stained with antibodies targeting connective tissue growth factor (CTGF) or VEGF and colabeled with antibodies directed against endothelial cells (CD31), myofibroblasts, or retinal pigment epithelium markers. Quantitative and colocalization analyses of antibody labeling were obtained through immunofluorescence confocal microscopy. Masson trichrome staining, cell counting of hematoxylin and eosin sections, and terminal dUTP nick-end labeling staining were performed.

RESULTS

High levels of fibrosis were observed in both groups. Cell apoptosis was higher (P = 0.05) in bevacizumab-treated membranes compared with controls. The bevacizumab group had a nonsignificant reduction in colocalization in CD31-CTGF and cytokeratin-VEGF studies compared with controls. Vascular endothelial growth factor in extracted membranes was positively correlated with vitreous levels of VEGF; CTGF in extracted membranes was negatively correlated with vitreous levels of CTGF.

CONCLUSION

Bevacizumab suppresses vitreous VEGF levels, but does not significantly alter VEGF or CTGF in diabetic membranes that may be explained by high baseline levels of fibrosis. Bevacizumab may cause apoptosis within fibrovascular membranes.

Change of Vascular Endothelial Growth Factor Levels following Vitrectomy in Eyes with Proliferative Diabetic Retinopathy

Purpose

To study the change of concentrations of vascular endothelial growth factor (VEGF) in vitreous cavity after vitrectomy in eyes with proliferative diabetic retinopathy (PDR).

Methods

In this retrospective study, intravitreal fluid samples were taken at baseline (beginning of the vitrectomy) and postoperatively (several days later after vitrectomy) at the time of prophylactic injection of bevacizumab in forty-eight eyes of forty-eight patients with PDR. Postvitrectomy fluid samples were divided into four groups according to the time interval between the vitrectomy and the injection (group 1, 3–5 days; group 2, 6–10 days; group 3, 11–15 days; group 4, 16–21 days; twelve eyes in each group). Postvitrectomy fluid sample was paired with baseline sample for each eye. VEGF concentrations in the samples were determined by enzyme-linked immunosorbent assay. Recurrent vitreous hemorrhage and neovascular glaucoma within six months postvitrectomy were also analyzed.

Results

Overall, the intravitreal VEGF level after vitrectomy (median, 36.95 pg/ml; range, 3.2–1,299.4 pg/ml) was significantly less than the VEGF level at baseline (median, 704.5 pg/ml; range, 30.6–1,981.1 pg/ml). Postoperative and baseline VEGF levels were significantly correlated (r = 0.499, p < 0.01). Both the absolute value of postoperative VEGF concentrations and the postop/baseline VEGF ratios declined with time and dramatically decreased in groups 3 and 4. In only two eyes, the postoperative VEGF level was even higher than the baseline VEGF level (postop/baseline VEGF ratio >1), and recurrent vitreous hemorrhage developed within six months in these two eyes.

Conclusions

After vitrectomy for PDR, intravitreal VEGF levels decreased substantially in the majority of patients, while persistent high-VEGF level occurred in a few individuals. Postoperative VEGF levels and postop/baseline VEGF ratio declined with time. The postop/preop VEGF ratio may serve as a predictor for late complications.

Incidence and Risk Factors for Tractional Macular Detachment after Anti-Vascular Endothelial Growth Factor Agent Pretreatment before Vitrectomy for Complicated Proliferative Diabetic Retinopathy

The study’s purpose was to determine the incidence, risk factors, and outcomes of tractional macular detachment after anti-vascular endothelial growth factor (VEGF) pretreatment before vitrectomy for complicated proliferative diabetic retinopathy. Patients who underwent primary vitrectomy for complicated proliferative diabetic retinopathy, from January 2012 to 31 December 2018, were enrolled. Ophthalmic and pre-operative data were extracted from electronic record systems. All eyes with a valuable Optical Coherence Tomography (OCT)performed within 5 days before injection of anti-VEGF and on the day of vitrectomy were included. Multivariable logistic regression showed that significant risk factors for developing tractional macular detachment included days between anti-VEGF and vitrectomy (OR, 0.71 [95% CI 0.65–0.76]; p < 0.001), vitreous hemorrhage (OR, 0.23 [95% CI 0.11–0.49]; p < 0.001), and age (OR, 1.05 [95% CI 1.02–1.08]; p < 0.001). Decision-tree analysis showed that the stronger predictors of tractional macular detachment were the time between anti-VEGF injection and vitrectomy (p < 0.001). Secondary predictors were the presence of vitreous hemorrhage (p = 0.012) in eyes that underwent vitrectomy between 6 and 10 days after anti-VEGF injection and younger age (p = 0.031) in eyes that underwent vitrectomy 10 days after anti-VEGF injection. Tractional macular detachment occurs in 10% of eyes after anti-VEGF injection, the main risk factors being days between anti-VEGF injection and vitrectomy, vitreous hemorrhage, and age.

Preoperative Bevacizumab for Tractional Retinal Detachment in Proliferative Diabetic Retinopathy: A Prospective Randomized Clinical Trial

PURPOSE

To assess the effectiveness and safety of an intravitreal injection of 1.25 mg bevacizumab (IVB) as a preoperative adjunct to small-gauge pars plana vitrectomy (PPV) compared with PPV alone in eyes with tractional retinal detachment secondary to proliferative diabetic retinopathy.

METHODS

This prospective, double-masked, randomized, multicenter, active-controlled clinical trial enrolled 224 eyes of 224 patients between November 2013 and July 2015. All eyes underwent a baseline examination including best-corrected visual acuity, color photos, optical coherence tomography, and fluorescein angiography. Data were collected on intraoperative bleeding, total surgical time, early (<1 month) postoperative vitreous hemorrhage, and mean change in best-corrected visual acuity at 12 months. P < .05 was considered statistically significant.

RESULTS

A total of 214 patients (214 eyes) were randomized in a 1:1 ratio to PPV plus IVB ([study group] 102 eyes) or PPV plus sham ([control] 112 eyes). Iatrogenic retinal breaks were noted intraoperatively in 35 eyes (34.3%) in the study group, and 66 eyes (58.9%) in the control group (P = .001). Grade 2 intraoperative bleeding was noted in 32 (31.3%) eyes in the study group and 58 (51.7 %) eyes in the control group (P = .001). Endodiathermy was necessary in 28 (27.4 %) eyes in the study group, compared with 75 (66.9%) eyes in the control group (P = .0001). Mean surgical time was 71.3 ± 32.1 minutes in the study group and 83.6 ± 38.7 minutes in the control group (P = .061).

CONCLUSION

Preoperative IVB seems to reduce intraoperative bleeding, improving surgical field visualization, and reducing intraoperative and postoperative complications. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Frequency and Risk Factors for Neovascular Glaucoma After Vitrectomy in Eyes with Diabetic Retinopathy: An Observational Study

INTRODUCTION

Vitrectomy is one of the main treatments for proliferative diabetic retinopathy (PDR). Postoperative neovascular glaucoma, in which it is difficult to obtain satisfactory results using conventional filtering surgery, is one of the most serious complications of vitrectomy. It often requires destructive surgery, such as ciliary body photocoagulation or freezing, and the outcome with regard to visual acuity (VA) is extremely poor. The purpose of this study was to evaluate the prevalence of neovascular glaucoma (NVG) after modern vitrectomy techniques and investigate how variables assessed before and after vitrectomy are associated with patients who develop NVG after PDR surgery.

METHODS

This was an observational study including the medical records of patients who underwent vitrectomy for PDR at Tianjin Eye Hospital from June 2014 to July 2016, were followed for at least 24 months postoperatively, and NVG developed within 2 years after surgery was recorded. Each patient underwent complete preoperative ophthalmic examinations in both preoperative and follow-up appointments. Factors associated with survival were determined using the Kaplan-Meier (KM) survival analysis to calculate the incidence of NVG after vitrectomy for PDR. Multivariable analysis was performed with the Cox regression proportional hazards model to verify the results of the analysis and eliminate interference factors between variables. All statistical analyses were performed using R statistical software ( http://www.r-project.org ) for Windows.

RESULTS

In all, 238 patients (238 eyes) fulfilled the study criteria. NVG occurred in 11 of 238 eyes (4.6%). The percentages of NVG development after vitrectomy at 6, 12, and 24 months were 0.42%, 3.3%, and 4.6%, respectively. After step analysis, multivariable regression identified preoperative high intraocular pressure (IOP) combined with retinal vein occlusion (RVO), severe PDR, no postoperative intravitreal injection of ranibizumab (IVR), and higher HbA1c levels as significant predictors of NVG.

CONCLUSION

Preoperative high IOP combined with RVO, severe PDR, no postoperative intravitreal injection of ranibizumab (IVR), and higher HbA1c levels are significant predictors of NVG after vitrectomy.

Surgical management of diabetic tractional retinal detachments

Tractional retinal detachment is an end-stage form of diabetic retinopathy that occurs when contractile forces in the vitreous and neovascular tissue lead to the detachment of the neurosensory retina. We review the literature related to the management of this disease. Preoperative planning includes appropriate patient selection, diagnostic and prognostic imaging, and medical optimization with reduction of systemic risk factors. Use of antivascular endothelial growth factor for preoperative treatment has had significant benefits for tractional retinal detachment repair in improving surgical efficiency and outcomes. Advances in microsurgical instrumentation are discussed, with attention to small-gauge vitrectomy with improved flow dynamics, viewing strategies, and lighting allowing bimanual surgery. Special emphasis is placed on bimanual surgical technique, choice of tamponade, and the avoidance of iatrogenic damage. Complications and special considerations are further explored. Based on our compilation of relevant literature, we propose a surgical algorithm for the management of these complex patients.

OCT angiography-based monitoring of neovascular regression on fibrovascular membrane after preoperative intravitreal conbercept injection

PURPOSE

To quantify the preoperative neovascular change pattern on the fibrovascular membrane (FVM) within 7 days after intravitreal injection of conbercept (IVC) using optical coherence tomography angiography (OCTA) in proliferative diabetic retinopathy (PDR).

METHODS

Prospective, observational study of PDR patients with visible FVM receiving or not receiving IVC. Neovascular changes were assessed by OCTA pre-IVC and 1, 3, 5, and 7 days post-IVC. Vessel skeleton density (SD) and vessel density (VD) were quantified by an intensity-based optical microangiography algorithm. The interclass correlation coefficient (ICC) was calculated to assess the agreement between measurements. The SD and VD were compared between follow-ups using repeated-measures analysis in the IVC group.

RESULTS

The ICC was 0.992 (95% confidence interval [CI]: 0.982-0.996) for SD and 0.926 (95% CI: 0.838-0.912) for VD of neovascularization. The neovascularization on FVM significantly regressed in the IVC group (n = 16) compared with no IVC (n = 8) (p = 0.001 for SD and p < 0.001 for VD). The comparisons between consecutive follow-ups showed a statistically significant reduction in SD and VD at 1 and 3 days post-IVC. However, from day 3 onward, the SD and VD remained unchanged. There was no development or progression of tractional retinal detachment within the 7-day period after IVC.

CONCLUSION

OCTA-based quantification of the neovascularization on FVM in PDR is feasible, with high inter-reader agreement. The regression of neovascularization reaches a plateau 3 days after IVC.

CLINICAL TRIAL REGISTRATION

This trial is registered with the Chinese Clinical Trial Registry ( http://www.chictr.org.cn , registration number ChiCTR-IPR-17014160).

Safety and efficacy of intravitreal conbercept injection after vitrectomy for the treatment of proliferative diabetic retinopathy

BACKGROUND/OBJECTIVES

The aim of this study was to evaluate the safety and efficacy of intravitreal conbercept (a recombinant fusion protein that primarily targets vascular endothelial growth factors) after vitrectomy for the management of proliferative diabetic retinopathy without tractional retinal detachment (TRD).

SUBJECTS/METHODS

Fifty patients with non-clearing vitreous haemorrhage (VH) due to proliferative diabetic retinopathy without TRD were enroled. They were randomly divided into control and treatment groups (25 eyes to each group) after they provided informed consent. The treatment group received intravitreal conbercept (10 mg/mL, 0.5 mg) immediately after surgery, while the control group did not. The best corrected visual acuity (BCVA) and the central retinal thickness were measured.

RESULTS

There were no significant between-group differences in baseline characteristics (P > 0.05), except in age (P = 0.003). Improvement in BCVA was significantly greater at 1, 4, 12, and 24 weeks post surgery in the treatment group than it was in the control group (P < 0.001). There were more cases in the control group who developed recurrent VH, but the recurrence rate of VH was not significantly different between the two groups at 12 and 24 weeks post surgery (P = 0.192 and  0.103). Central retinal thickness was lower in the treatment group than in the control group at 1 week (P = 0.012), 4 weeks (P = 0.01), 12 weeks (P = 0.001), and 24 weeks (P = 0.004) post surgery, which were statistically significant.

CONCLUSIONS

An intravitreal injection of conbercept after vitrectomy improved visual acuity and seemed to reduce the recurrence of VH resulting in prompt visual recovery in the PDR patients.

Effect of Intravitreal Bevacizumab Injection on Corneal in vivo Biomechanics: A Pilot Study

Purpose

To evaluate the effect of intravitreal bevacizumab (IVB) injection on corneal biomechanical parameters as measured by the ocular response analyzer (ORA) and Corneal Visualization Scheimpflug Technology (CorVis).

Methods

In this prospective pilot study, ORA and CorVis parameters were recorded before and after a three-month course of IVB injection therapy in 16 patients in the injected and the contralateral non-injected control eyes. The changes in the recorded parameters in each group and the differences between the two groups were evaluated and compared.

Results

None of the changes in ORA parameters were statistically significant in the injected and non-injected groups before and three months after injection, except for corneal resistance factor (CRF) in injected eyes (paired t-test, P = 0.039). The differences in corneal hysteresis (CH) and CRF were not statistically significant between the two groups (P = 0.441 and 0.236, respectively), but significant differences were noted between corneal compensated IOP (IOPcc) and Goldmann-correlated IOP (IOPg) (P = 0.045 and 0.047, respectively). None of the changes in CorVis parameters were statistically significant in the groups before and at the end of study, except for the time of first corneal applanation (TAp1 ms) in the injected group (P = 0.040, paired t-test). Differences in TAp1, length of the second corneal applanation (LAp2 mm), velocity of the second corneal applanation (VAp2 m/s), intraocular pressure (IOP), and central corneal thickness (CCT) also showed borderline significance between the two groups.

Conclusion

In this pilot study IVB injection could change CRF, IOPcc, IOPg, and TAP1 as measured by ORA and CorVis.

Preoperative Timing of Intravitreal Bevacizumab Injection for Proliferative Diabetic Retinopathy Patients

OBJECTIVE

To evaluate the changes in aqueous concentrations of inflammatory cytokines and fibrosis-related factors, and to detect the expression of vascular endothelial growth factor (VEGF) and proliferating cells in fibrovascular membranes (FVMs) of patients with proliferative diabetic retinopathy (PDR) after injection of intravitreal bevacizumab (IVB).

METHODS

Forty-two eyes of 42 patients with PDR, including 28 eyes that received IVB (1.25 mg) 2, 5, and 14 days before pars plana vitrectomy (PPV), and 14 eyes without IVB, were enrolled, in addition to 10 eyes of 10 patients with nondiabetic ocular diseases. Aqueous concentrations of inflammatory cytokines and fibrosis-related factors were analyzed by a multiplex bead assay. Fluorescence immunostaining was performed to examine the expression of VEGF and proliferating cells in the excised epiretinal membranes.

RESULTS

PDR eyes without IVB had the highest vitreous VEGF levels, and the level was statistically significant compared with that of PDR eyes that received IVB 2 days before surgery, PDR eyes that received IVB 5 days before surgery, and nondiabetic eyes (p = 0.011, p = 0.012, and p < 0.001, respectively). The expression of fibroblastic cells and connective tissue growth factor increased in epiretinal FVMs of the IVB group 21 days after treatment.

CONCLUSIONS

IVB injection may lead to a decrease in the intraocular concentrations of VEGF after 2-5 days and induce the formation of proliferation after 21 days, which suggests that PPV in PDR patients should take place within 1 week of the administration of preoperative IVB.

Vitreous and intraretinal macular changes in diabetic macular edema with and without tractional components

Diabetic macular edema (DME) is still one of the main causes of visual impairment. Repeated intravitreal injections of ranibizumab are considered the gold standard treatment, but the efficacy in patients with prominent cystic characteristics remains uncertain. In diabetic retinas, the identification of both antero-posterior and, particularly, tangential tractions is crucial to prevent misdiagnosis of tractional and refractory DME, and therefore to prevent poor treatment outcomes. The treatment of tractional DME with anti-VEGF injections could be poorly effective due to the influence of a tractional force. Pars plana vitrectomy (PPV) is a surgical procedure that has been widely used in the treatment of diffuse and refractory DME. Anatomical improvement, although stable and immediate, did not result in visual improvement. PPV with internal limiting membrane (ILM) peeling for the treatment of non-tractional DME in patients with prominent cysts (> 390 μm) causes subfoveal atrophy, defined as "floor effect". Epiretinal tangential forces and intraretinal change evaluation by SD-OCT of non-tractional DME are essential for determining appropriate management.

Bevacizumab before Diabetic Vitrectomy: A Clinical Trial Assessing 3 Dosing Amounts

PURPOSE

To evaluate the optimal dosing of preoperative intravitreal bevacizumab (IVB) in patients undergoing pars plana vitrectomy (PPV) for manifestations of proliferative diabetic retinopathy (PDR).

DESIGN

Randomized clinical trial.

PARTICIPANTS

Two hundred six patients with severe manifestations of PDR underwent PPV at a single university-based hospital.

METHODS

Patients were randomized into 1 of 3 treatment groups: group A received 0.625 mg IVB (0.025 ml) 1 to 10 days before PPV, group B received 1.25 mg IVB (0.05 ml) 1 to 10 days before PPV, and group C received 2.5 mg IVB (0.1 ml) 1 to 10 days before PPV.

MAIN OUTCOME MEASURES

The primary outcome was best-corrected visual acuity (BCVA) at 6 months. Secondary outcome measures were rates of perioperative tractional retinal detachment (TRD) development, intraoperative and postoperative complications, and incidence of unplanned PPV at 6 months.

RESULTS

One hundred sixty-seven patients underwent PPV and completed 6 months of follow-up. There were no significant differences between treatment groups regarding baseline characteristics, final BCVA, intraoperative complications, postoperative complications, or unplanned PPV rates. There were no patients in group A (0.0%), 3 patients in group B (7.0%), and 5 patients in group C (8.5%) who demonstrated perioperative TRD after IVB administration, but before PPV (P = 0.0283). This difference was significant between groups A and B (P = 0.0494) and between groups A and C (P = 0.0080).

CONCLUSIONS

This randomized clinical trial demonstrated that patients receiving the 0.625-mg dose of IVB before PPV for the treatment of PDR-related manifestations showed similar visual acuity, but a lower incidence of perioperative TRD development compared with patients receiving the 1.25-mg and 2.5-mg doses. Clinicians should consider adopting the lowest effective dose, 0.625 mg, into clinical practice. The current study is limited by the lack of a control group receiving no IVB before PPV.

Research progress on the role of connective tissue growth factor in fibrosis of diabetic retinopathy

Diabetic retinopathy (DR) is one of the most important types of diabetic microangiopathy, which is a specific change of fundus lesions and is one of the most serious complications of diabetes. When DR develops to proliferative DR, the main factors of decreasing vision, and even blindness, include retinal detachment and vitreous hemorrhage caused by contraction of blood vessels by fiber membrane. Recent studies reported that the formation of fiber vascular membrane is closely related to retinal fibrosis. The connective tissue growth factor (CTGF) is a cytokine that is closely related to DR fibrosis. However, its mechanism is poorly understood. This paper summarizes the recent studies about CTGF on DR fibrosis for a comprehensive understanding of the role and mechanism of CTGF in PDR.

Effect of intravitreal conbercept treatment before vitrectomy in proliferative diabetic retinopathy

AIM

To evaluate the safety and efficacy of intravitreal conbercept (IVC) injections as pretreatment for pars plana vitrectomy (PPV) in severe proliferative diabetic retinopathy (PDR).

METHODS

This was a retrospective chart review of all patients who underwent PPV for PDR from January 2014 to October 2016. Patients who underwent IVC injection before PPV were assigned to the IVC group; the others were assigned to the control group. The IVC was performed 3-7d before surgery in the IVC group. All the eyes in the two groups were operated by the same doctor to complete the vitrectomy. Intraoperative complications and the changes in best-corrected visual acuity (BCVA) before and after surgery were compared between the two groups.

RESULTS

A total of 68 eyes of 63 patients (22 eyes in the IVC group and 46 eyes in the control group) were examined. The risk of intraoperative bleeding was lower in the IVC group (2/22) than in the control group (25/46, P=0.000). Furthermore, the use of endodiathermy was significantly lower in the IVC group (1/22) than in the control group (12/46, P=0.047). The surgical time in the IVC group (112.64±34.52min) was significantly shorter than in the control group (132.85±40.04min, P<0.05). Compared to the BCVA before surgery, the mean BCVA was significantly improved after surgery for both groups (P<0.05).

CONCLUSION

PPV is an effective treatment and can improve vision in patients with PDR. Preoperative intravitreal injection of conbercept could reduce the chances of intraoperative bleeding and the use of endodiathermy and shorten the operative time, which are beneficial in the management of PDR.

Preoperative Bevacizumab Administration in Proliferative Diabetic Retinopathy Patients Undergoing Vitrectomy: A Randomized and Controlled Trial Comparing Interval Variation

PURPOSE

To assess the optimal interval of preoperative intravitreal bevacizumab (IVB) administration in diabetic subjects undergoing pars plana vitrectomy (PPV) for severe manifestations of active proliferative diabetic retinopathy (PDR).

DESIGN

Randomized clinical trial.

METHODS

One hundred and fifty-six patients with PDR-related complications requiring PPV were prospectively randomized into 1 of 2 treatment groups: Group A received IVB (2.5 mg/0.1 mL) 1-3 days before PPV, while Group B received IVB (2.5 mg/0.1 mL) 5-10 days before PPV. The primary outcome was best-corrected visual acuity (BCVA) at 6 months follow-up. Secondary outcome measures were intraoperative surgery time, intraoperative complications, postoperative complications, and incidence of unplanned PPV at 6 months follow-up.

RESULTS

One hundred and twenty-five subjects underwent PPV and completed the 6-month follow-up interval. Group B patients had better final BCVA (P = .033) and were less likely to have a postoperative complication (P = .018) when compared to Group A patients. The mean difference in final BCVA between groups was 0.22 logMAR (95% confidence interval: 0.02-0.43, P = .017). Group A was 3.90 (95% confidence interval: 1.08-17.31, P = .046) times more likely to have a loss of 1 or more logMAR lines of final BCVA when compared to Group B. There were no significant differences among the treatment groups with regard to baseline features, intraoperative surgery time, intraoperative complications, and incidence of unplanned PPV during the study interval.

CONCLUSIONS

This randomized clinical trial demonstrated better postoperative outcomes at 6 months when subjects received preoperative IVB 5-10 days before PPV compared to 1-3 days for the treatment of PDR-related complications.

Serous retinal detachment after panretinal photocoagulation for proliferative diabetic retinopathy: a case report

BACKGROUND

Proliferative diabetic retinopathy is a major cause of visual impairment in working-age adults worldwide. Panretinal photocoagulation is a cornerstone in its management; however, it may include a range of side effects and complications, one of these being serous retinal detachment. To the best of our knowledge, this is the first report of the use of intravitreal injection of bevacizumab for serous retinal detachment after panretinal photocoagulation.

CASE PRESENTATION

A 24-year-old Saudi man with poorly controlled type 1 diabetes presented with bilateral progressive proliferative retinopathy in spite of several sessions of panretinal photocoagulation. After one additional such session, he developed bilateral serous retinal detachment and vision loss, which was managed with a single bilateral intravitreal bevacizumab injection. The serous retinal detachment subsided with partial recovery of vision.

CONCLUSIONS

Serous retinal detachment after panretinal photocoagulation for proliferative diabetic retinopathy is a rare complication nowadays. In this case, it seems that excessive photocoagulation exceeded the energy-absorbing capacity of the retinal pigment epithelium, leading to a disruption of the blood-retinal barrier. A single injection of bilateral intravitreal bevacizumab was sufficient to control the serous retinal detachment. This effect may have been due to a reduction of vascular leakage resulting from the mechanism of action of this drug. No complications were noted from the injection. Caution should be exerted when attempting bilateral panretinal photocoagulation.

Neovascular glaucoma after vitrectomy in patients with proliferative diabetic retinopathy

To evaluate the prevalence and risk factors of neovascular glaucoma (NVG) after vitrectomy in patients with vitreous hemorrhage associated with proliferative diabetic retinopathy (PDR). This retrospective, noncomparative, observational study included 127 eyes of 127 patients with PDR who received vitrectomy with a follow-up period of at least 6 months. The prevalence of NVG and associated risk factors were assessed including sex, age, previous panretinal photocoagulation, baseline intraocular pressure, combined phacovitrectomy, and pretreatment with intravitreal bevacizumab (IVB) before vitrectomy for the treatment of vitreous hemorrhage. NVG developed in 15 (11.8%) of 127 patients. Of the 15 eyes with NVG, 11 cases (73.3%) postoperatively developed NVG within 6 months. Postoperative NVG was associated with preoperative IVB treatment (odds ratio, 4.43; P = 0.019). The prevalence of NVG after vitrectomy was 11.8%, and an associated risk factor for NVG was preoperative IVB for the treatment of vitreous hemorrhage.

Vitreoretinal interface abnormalities in patients treatedwith ranibizumab for diabetic macular oedema

Purpose

Intravitreal anti-vascular endothelial growth factor (VEGF) agents are effective in the treatment of central involving diabetic macular oedema (DMO). Vitreoretinal interface abnormalities (VRIA) are common in patients with DMO, and the effect of these on the response to anti-VEGF treatment is unclear. Furthermore the effect of anti-VEGF agents on the VRIA itself is uncertain.

Method

Prospective study of consecutive patients treated with ranibizumab (RZB) for DMO as part of routine clinical care in one eye unit over a 1-year period. Visual acuity (Va), central retinal thickness (CRT) and injection frequency data was recorded on an electronic database. Treatment was initiated with four monthly RZB injections and then a monthly PRN regime. All patients underwent high-density spectral-domain optical coherence tomography (SDOCT) at baseline and 12 months. The SDOCTs were graded by two observers masked to the outcome.

Results

One hundred and four eyes (77 patients) were included in the analysis. The mean age was 62 years, and 62% were male. The mean presenting vision was 62 letters and CRT 472 μm. Eighty eyes retained stable Va, and 17 had an improvement in Va. At baseline, 39 eyes had associated focal vitreomacular adhesion (VMA) and by 12 months this reduced to 30 (p = 0.04), with 12 releasing VMA and three developing it. Patients with VMA had significantly better final Va than those without VMA. Improvement in CRT was greatest in those where VMA released during the study. Forty-five eyes had some degree of foveal involving epiretinal membrane (ERM) at baseline, and 28 were considered to have clinically significant ERM. There was no clinically relevant change in ERM during the study. Patients with significant ERM at baseline had a lower final vision. Multivariate analysis showed that ERM and more severe retinopathy at baseline were predictive of less visual improvement (p < 0.01). Shorter intraretinal cyst length, ERM and the absence of VMA at baseline were predictive of a worsened anatomical response (p < 0.001).

Conclusion

VRIA are related to outcome in patients treated with RZB. ERM was associated with a worsened visual and anatomic response, and VMA with an improved anatomical response particularly when spontaneous VMA release occurred during treatment. The presence and severity of ERM was not affected by RZB treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s00417-016-3562-0) contains supplementary material, which is available to authorized users.

The relationship between anti-vascular endothelial growth factor and fibrosis in proliferative retinopathy: clinical and laboratory evidence

PURPOSE

To investigate the progression of epiretinal membranes after intravitreal bevacizumab (IVB) injection therapy in patients with proliferative membranes and evaluate the changes in fibrosis-related cytokines in retinal pigment epithelial cells and glial cells after treatment with bevacizumab.

METHODS

Retrospective study of the proliferative membranes in patients with and without IVB therapy. In vitro, the human adult retinal pigment epithelial (ARPE-19) cells and BV2 microglial cell lines were incubated in different bevacizumab concentrations under hypoxic conditions. Cell culture supernatants and cell lysates were harvested after incubation for 24, 48 or 72 hours for ELISA and western blot.

RESULTS

Bevacizumab accelerated fibrosis in patients with proliferative membranes. Immunofluorescence analysis revealed more intense transforming growth factor β2 (TGFβ2) and connective tissue growth factor (CTGF) staining in IVB-treated proliferative diabetic retinopathy (PDR) membranes compared with membranes of patients not receiving IVB therapy. This result was consistent with real-time PCR results. Bevacizumab incubation significantly upregulated TGFβ2 and CTGF in ARPE-19 cells and BV2 microglial cells, but ciliary neurotrophic factor (CNTF) expression was upregulated only in BV2 microglial cells.

CONCLUSIONS

Anti-vascular endothelial growth factor treatment likely accelerates fibrosis in PDR patients via upregulation of TGFβ2, CTGF and CNTF, suggesting the importance of adjunctive therapy for retinal fibrosis.

Evaluation of Intravitreal Ranibizumab on the Surgical Outcome for Diabetic Retinopathy With Tractional Retinal Detachment

This study aims to investigate intravitreal injection of Ranibizumab on the surgical outcome for diabetic patients who had tractional retinal detachment but did not receive any preoperative retinal photocoagulation.Ninety-seven patients (97 eyes) who had diabetic retinopathy with tractional retinal detachment were enrolled to receive 23-G pars plana vitrectomy (PPV). They were assigned to an experimental group (Group I, n = 47 eyes) and a control group (Group II, n = 50 eyes). The patients in Group I were given 1 injection of intravitreal Ranibizumab (Lucentis 0.5 mg/0.05 mL) 1 week before surgery, whereas those in Group II went down to surgery directly. Follow-ups were performed for 6 months to 3 years (16 ± 6 months), and indicators observed included postoperative best-corrected visual acuity, complications, and retinal thickness in the macula measured by optical coherence tomography.In Group I, BCVA improved from logMAR 1.92 ± 0.49 to logMAR 0.81 ± 0.39 following surgery, whereas in Group II, BCVA improved from logMAR 1.91 ± 0.49 to logMAR 0.85 ± 0.41. There was significant postoperative gain in vision, but there was no significant difference between the 2 groups at postoperative follow-up visits. The mean duration of vitrectomy in Group I and Group II was (40 ± 7) minutes and (53 ± 9) minutes, respectively, with significant difference. Iatrogenic breaks were noted in 5 eyes (11%) in the experimental group and 17 eyes (34%) in the control group; the difference was significant. The retinal thickness in the macula measured by OCT was (256 ± 44) μm and (299 ± 84) μm in Group I and Group II respectively with significant difference. Besides, there were significantly more eyes in Group II that required silicone oil tamponade and postoperative retinal photocoagulation.23-G PPV combined with intravitreal tamponade and panretinal photocoagulation still remains an effective regimen for the treatment of diabetic retinopathy complicated with tractional retinal detachment. Preoperative intravitreal injection of Ranibizumab could shorten surgical duration, reduce intraoperative complications, and sometimes spare the need for silicone oil tamponade and postoperative retinal photocoagulation, alleviating patients' suffering from surgery.

Changes in vitreous VEGF, bFGF and fibrosis in proliferative diabetic retinopathy after intravitreal bevacizumab

AIM

To evaluate the relationship between intravitreal bevacizumab (IVB) treatment and the levels of vitreous vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and vitreous-retina surface fibrosis in patients with proliferative diabetic retinopathy (PDR).

METHODS

This study was a prospective, open-label, controlled, randomized clinical trial. Sixty-eight eyes of PDR patients (n=53) and macular hole patients (n=15) were enrolled in this study. Thirty-four eyes of the PDR patients received IVB before vitrectomy. Twenty-three of the 34 PDR patients received IVB treatment 5d before vitrectomy (subgroup a), and 11 of the 34 PDR patients received IVB treatment greater than 2wk prior to vitrectomy (subgroup b). Nineteen of the PDR patients did not receive IVB treatment at any time prior to vitrectomy. The levels of bFGF and VEGF in vitreous samples were measured using enzyme-linked immunosorbent assay (ELISA) and the degree of vitreoretinal fibrosis was characterized using clinical data and data obtained intra-operatively.

RESULTS

In PDR patients, VEGF and bFGF levels were significantly increased compared to non-PDR (control) subject's eyes (P<0.01). In PDR patients, vitreous VEGF levels were significantly decreased following IVB treatment compared to PDR patients that did not receive IVB treatment (P<0.01). The degree of vitreoretinal fibrosis was significantly increased in subgroup b compared to subgroup a(P<0.05) and to patients that did not receive IVB (P<0.05). Vitreous bFGF levels were significantly greater in subgroup b than subgroup a (P<0.01) or in patients who did not receive IVB treatment (P<0.05). A Spearman's rank correlation test indicated that higher levels of vitreous bFGF, but not VEGF, correlated with the degree of vitreoretinal fibrosis.

CONCLUSION

We found that bFGF levels increase in PDR patient's vitreous after IVB treatment longer than two weeks prior to vitrectomy and correlated with the degree of fibrosis after IVB treatment. These findings suggest vitreous fibrosis is increased in PDR patients after IVB treatment may be due to increased levels of bFGF.

Induction with intravitreal bevacizumab every two weeks in the management of neovascular age-related macular degeneration

PURPOSE

To explore the benefit of rapid induction with intravitreal bevacizumab for neovascular age-related macular degeneration (AMD).

DESIGN

Single-institution prospective randomized pilot study.

METHODS

Patients with treatment-naïve neovascular AMD were randomized 1:1:1 into 1 of 3 groups based on the induction sequence: (1) every 2 weeks for 3 consecutive injections; (2) every 4 weeks for 3 consecutive injections; and (3) immediate pro re nata (prn) after the first injection. Retinal angiomatous proliferation and polypoidal choroidal vasculopathy were excluded. Best-corrected visual acuity (BCVA) and central retinal thickness using optical coherence tomography (OCT) were measured at baseline and at each follow-up. After induction, bevacizumab was administered as needed based mainly on OCT. Main outcome measure was mean initial fluid-free interval after induction. Secondary outcomes were mean improvement in BCVA and central retinal thickness.

RESULTS

Each group included 30 patients (30 eyes). Mean initial fluid-free interval was 2.4, 3.4, and 3.5 months for biweekly induction, monthly induction, and immediate prn groups, respectively (P = .03). Significance was lost when corrected for age and sex (P = .073). Mean improvement in BCVA, central retinal thickness, and total number of injections were similar among the groups at 12 months. Six eyes in the biweekly induction group developed subretinal fibrosis vs no eyes in the other 2 groups (P = .003).

CONCLUSION

Biweekly induction with intravitreal bevacizumab for treatment-naïve neovascular AMD does not increase initial fluid-free interval or cause significant anatomic and functional benefit compared to monthly induction or immediate prn. There is also the potential development of subretinal fibrosis with biweekly induction.

Overexpression of CD163 in vitreous and fibrovascular membranes of patients with proliferative diabetic retinopathy: possible involvement of periostin

AIM

To determine whether CD163, a specific marker for M2 macrophages, is involved in the formation of preretinal fibrovascular membranes (FVMs) present in eyes with proliferative diabetic retinopathy (PDR).

METHODS

We measured the levels of soluble (s)CD163, periostin and vascular endothelial growth factor by sandwich ELISA in vitreous samples from 74 eyes of 62 patients with PDR, 20 eyes of 18 patients with proliferative vitreoretinopathy, and 56 eyes of 54 patients with non-diabetic ocular diseases (control group). Immunohistochemical analyses were performed to determine the expressions of CD68, CD163 and periostin in the surgically resected FVMs and idiopathic epiretinal membranes (ERMs).

RESULTS

The concentrations of sCD163 and periostin in the vitreous were significantly higher in patients with PDR than in non-diabetic controls (p<0.0001). There was a strong correlation between the vitreous concentrations of sCD163 and periostin. The mean vitreous level of sCD163 was significantly higher in eyes with FVMs than in those without FVMs (epicentre only). The number and percentage of CD163+ macrophages were significantly higher in the FVMs than in the idiopathic ERMs. Immunohistochemical analysis showed co-localisation of CD163 and periostin in FVM cells.

CONCLUSIONS

These findings indicate that the overexpression of CD163 by macrophages may be involved in the development of FVMs partly through periostin production.

Intravitreal injection of ranibizumab and CTGF shRNA improves retinal gene expression and microvessel ultrastructure in a rodent model of diabetes

Therapeutic modalities targeting vascular endothelial growth factor (VEGF) have been used to treat neovascularization and macular edema. However, anti-VEGF treatment alone may cause up-regulation of connective tissue growth factor (CTGF) in the retina, increasing the risk of fibrosis and tractional retinal detachment. Therefore, in this study, we employ a novel dual-target intervention that involves intravitreal injection of the VEGF inhibitor ranibizumab and a transfection reagent-treated non-viral vector carrying anti-CTGF short hairpin RNA (shRNA) driven by human RNA polymerase III promoter U6. The effects of the dual-target intervention on the expression of VEGF and CTGF and on microvessel ultrastructure were examined in retina of streptozocin-induced diabetic rats. CTGF was significantly up-regulated at week 8 after diabetic induction, whereas VEGF was not up-regulated until week 10. The high expression of both genes was maintained at week 12. Transmission electron microscopy also revealed progressive exacerbation of microvessel ultrastructure during the same period. In addition, ranibizumab significantly lowered VEGF but elevated CTGF mRNA, whereas CTGF shRNA significantly reduced the mRNA levels of both CTGF and VEGF in diabetic retinas. Importantly, dual-target intervention normalized the transcript levels of both target genes and ameliorated retinal microvessel ultrastructural damage better than either single-target intervention. These results suggest the advantages of dual-target over single-target interventions in diabetic retina and reveal a novel therapeutic modality for diabetic retinopathy.

Altered vascular microenvironment by bevacizumab in diabetic fibrovascular membrane

PURPOSE

The purpose of this study was to evaluate the impact of intravitreal bevacizumab (IVB) on three cellular components (vascular endothelial cells, pericytes, and myofibroblasts) of the vascular microenvironment in fibrovascular membranes (FVMs) of patients with proliferative diabetic retinopathy.

METHODS

Immunohistological studies with antibodies of CD34, αSMA, and transforming growth factor-β were performed on 20 surgical specimens obtained during a pars plana vitrectomy from 8 IVB-treated eyes, whereas 12 remained untreated. Four different indexes of vascular phenotype (vascular area, vascular major axis, CD34 endothelial area, and blood vessel density) and αSMA expression in vascular and stromal components were quantitatively analyzed.

RESULTS

The intraluminal area of blood vessels, CD34 endothelial area, and the blood vessel density in IVB-treated FVMs were significantly less than in untreated FVMs. The number of CD34 blood vessels in IVB-treated FVMs was similar to that in untreated FVMs. Intravitreal bevacizumab could not affect vascular and stromal αSMA area significantly. However, the ratio of vascular αSMA area/CD34 area was significantly higher in IVB-treated FVMs than in untreated FVMs. Transforming growth factor-β expression could be observed in the IVB-treated FVM.

CONCLUSION

Intravitreal bevacizumab might primarily affect blood vessels, and the effects on pericytes and myofibroblasts might be secondary. Intravitreal bevacizumab treatment regulates vascular microenvironment by the contraction of blood vessels, the increasing pericyte ratio, and transforming growth factor-β expression in FVMs of patients with proliferative diabetic retinopathy.

Outcome of a Single Intravitreal Bevacizumab Injection on the Visual Acuity and Course of Pars Plana Vitrectomy in Proliferative Diabetic Retinopathy

Abstract Purpose: To evaluate the effect of a single intravitreal 1.25 mg/0.05 ml bevacizumab (IVB) (Avastin, Genentech) injection on the visual outcome and both intraoperative and postoperative course of pars plana vitrectomy (PPV) in proliferative diabetic retinopathy. Study Design: Prospective case-control interventional comparative study. Methods: One hundred patients (100 eyes) were divided into two groups: Group I had undergone PPV with preoperactive IVB (50 patients), and Group II had undergone PPV without IVB (50 patients). Best corrected visual acuity (BCVA), intraoperative and postoperative complications were compared between both groups. Patients were followed-up for one year. Results: After one year, there was a highly statistically significant difference in the mean BCVA, as it was (0.146 ± 0.103) in Group I and 0.069 ± 0.049 in Group II with (p < 0.001), while mean bleeding frequency in Group I was 0.7 ± 0.78 times/case with range between 0 and 2 bleeding attacks/case and mean bleeding frequency in Group II was 3.12 ± 1.31times/case with range between 3 and 6 bleeding attacks/case and the difference was statistically significant as (p < 0.001). Diathermy was used in Group I in 15 patients only with mean frequency of 0.3 ± 0.46 times/case with range between 0 and 1 attack/case; while diathermy was used in all cases in Group II with mean frequency of 2.4 ± 1.06 times/case with range between 1 to 4 times/case and this difference was also statistically significant as p < 0.001. Postoperative vitreous hemorrhage developed in 3 eyes (6%) in Group I and 15 eyes (30%) in Group II and this difference was statistically significant (p < 0.003). All the other intraoperative and postoperative complications were reduced in Group I, but with no statistically significant difference between both groups. Conclusions: The use of intravitreal bevacizumab before pars plana vitrectomy is beneficial in improving visual outcome, minimizing the incidence of intraoperative bleeding and reducing the need for intraoperative diathermy.

[VEGF inhibitors in vitreoretinal interventions]

Vascular endothelial growth factor (VEGF) inhibitors are being used for an increasing number of indications. Beyond the classical use in exudative macular degeneration and macular edema, they are being used, for example off-label as additive treatment together with panretinal laser photocoagulation or in preparation for vitrectomy for ischemic retinopathy. In preparation for vitreoretinal surgery VEGF inhibitors are usually given prior to surgery. When given as an adjunct to laser treatment, VEGF inhibitors can be given either consecutively or parallel to laser photocoagulation. In most cases, however, anti-VEGF treatment does not render laser coagulation dispensable. The greatest danger with anti-VEGF treatment in the context of ischemic retinopathies lies in the fact that proliferative membranes are misjudged or overlooked. In these cases, anti-VEGF treatment can induce contraction of these membranes with induction of consecutive tractional retinal detachment. This review summarizes the current knowledge on VEGF inhibition as an adjunct to vitreoretinal surgery and also points out the gaps in the current knowledge and the need for further research.

Vitrectomy with or without preoperative intravitreal bevacizumab for proliferative diabetic retinopathy: a meta-analysis of randomized controlled trials

PURPOSE

To compare safety and functional outcomes of vitrectomy with or without preoperative intravitreal bevacizumab (IVB) for proliferative diabetic retinopathy (PDR).

DESIGN

A meta-analysis of randomized controlled trials.

METHODS

PubMed, Medline, EMBASE, and Cochrane Controlled Trials Register were searched to identify potentially relevant randomized controlled trials. A total of 394 participants with 414 eyes in 8 trials were analyzed using RevMan 5.1 software. The primary measures included intraoperative bleeding, total surgical time, and early and late recurrent hemorrhage.

RESULTS

Vitrectomy with IVB pretreatment achieved shorter overall surgical time (mean difference = -26.89 minutes, 95% confidence interval [CI] -31.38 to -22.39, P < .00001) and smaller number of endodiathermy applications (mean difference = -3.46, 95% CI -6.43 to -0.49, P = .02) compared to vitrectomy alone. The IVB group was also associated with less intraoperative bleeding (odds ratio [OR] = 0.10; 95% CI 0.02 to 0.46; P = .003) and recurrent vitreous hemorrhage within first month (OR = 0.35; 95% CI 0.21 to 0.58; P < .0001), but the proportion of recurrent vitreous hemorrhage after the first month was comparable between both groups. There were no significant differences in other complication rates between the 2 groups, with the exception of iatrogenic retinal break, which was more likely with the vitrectomy-alone group (OR = 0.27, 95% CI 0.12 to 0.63, P = .003). Results were robust to sensitivity analyses.

CONCLUSIONS

Adjuvant intravitreal injection of bevacizumab prior to vitrectomy in PDR patients significantly eased the procedure, diminished intraoperative complications, and reduced early postoperative hemorrhage without increasing the risk of vision-threatening complications. Further trials should determine the optimal interval and dosage for IVB injection.

A shift in the balance of vascular endothelial growth factor and connective tissue growth factor by bevacizumab causes the angiofibrotic switch in proliferative diabetic retinopathy

Introduction

In proliferative diabetic retinopathy (PDR), vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF) may cause blindness by neovascularisation followed by fibrosis of the retina. It has previously been shown that a shift in the balance between levels of CTGF and VEGF in the eye is associated with this angiofibrotic switch. This study investigated whether anti-VEGF agents induce accelerated fibrosis in patients with PDR, as predicted by this model.

Methods

CTGF and VEGF levels were measured by ELISA in 52 vitreous samples of PDR patients, of which 24 patients had received intravitreal bevacizumab 1 week to 3 months before vitrectomy, and were correlated with the degree of vitreoretinal fibrosis as determined clinically and intra-operatively.

Results

CTGF correlated positively, and VEGF correlated negatively with the degree of fibrosis. The CTGF/VEGF ratio was the strongest predictor of fibrosis. Clinically, increased fibrosis was observed after intravitreal bevacizumab.

Conclusions

These results confirm that the CTGF/VEGF ratio is a strong predictor of vitreoretinal fibrosis in PDR, and show that intravitreal anti-VEGF treatment causes increased fibrosis in PDR patients. These findings provide strong support for the model that the balance of CTGF and VEGF determines the angiofibrotic switch, and identify CTGF as a possible therapeutic target in the clinical management of PDR.

Anti-VEGF Agents for Ocular Angiogenesis and Vascular Permeability

We review articles describing intravitreal injection of anti-VEGF drug trials, while discussing the mechanisms of the action of anti-VEGF antibodies, and also evaluating their outcomes. Intraocular injections of anti-VEGF drug are considered to be an effective treatment for macular edema after retinal vein occlusion, however, recurrent/persistent edema is common. The recent reports may lead to a shift in treatment paradigm for DME, from laser photocoagulation, to newer approaches using anti-VEGF drugs. There have been several well-publicized prospective, randomized studies that demonstrated the efficacy of intravitreal injection of anti-VEGF drugs for patients with AMD. Adjuvant bevacizumab for neovascular glaucoma may prevent further PAS formation, and it is likely to open up a therapeutic window for a panretinal photocoagulation and trabeculectomy. Intravitreal injection of bevacizumab (IVB) results in a substantial decrease in bleeding from the retinal vessels or new vessels during a standard vitrectomy. IVB has also been reported to be effective for inducing the regression of new vessels in proliferative diabetic retinopathy. The use of bevacizumab in stage 4 or 5 retinopahty of permaturity (ROP) is to reduce the plus sign to help reduce hemorrhage during the subsequent vitrectomy. Some authors reported cases of resolution of stage 4 A ROP after bevacizumab injection.