Short-term effects of intravitreal bevacizumab (Avastin(®)) on retrobulbar hemodynamics in patients with neovascular age-related macular degeneration

Early Effects of Inactivated (CoronaVac) SARS-CoV-2 Vaccine on Retrobulbar Vascular Blood Flow and Retinal Vascular Density

AIMS

We aimed to investigate the early effects of inactivated SARS-CoV-2 vaccine on retrobulbar vascular blood flow and retinal vascular density in healthy subjects.

METHODS

Thirty-four eyes of 34 healthy volunteers who received the CoronaVac (Sinovac Life Sciences, China) were included in this prospective study. Resistive index (RI), pulsatility index (PI) and peak systolic velocity (PSV) of the ophthalmic artery (OA), central retinal artery (CRA), and the temporal and nasal posterior ciliary arteries (PCA) were evaluated with color Doppler ultrasonography (CDUS) before vaccination, at the 2^nd and 4^th weeks after vaccination. Superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD), foveal avascular zone (FAZ), and choriocapillaris blood flow (CCF) measurements were made using optical coherence tomography angiography (OCTA).

RESULTS

When compared to the pre-vaccination values, there was no significant change in OA-PSV, temporal-nasal PCA-PSV, CRA-EDV, temporal-nasal PCA-EDV at 2^nd and 4^th weeks after vaccination. However statistically significant reductions were found in the OA-RI, OA-PI, CRA-RI, CRA-PI, temporal-nasal PCA-RI, temporal-nasal PCA-PI values, CRA-PSV at post-vaccination 2^nd week (p<0.05 for all). While there was sustained reduction in OA-RI, OA-PI, CRA-PSV, and nasal PCA-RI values at 4^th week after vaccination, the change in CRA-RI, CRA-PI, temporal PCA-RI, temporal-nasal PCA-PI values were not significant compared to pre-vaccination values. There was no statistically significant difference in the SCP-VD, DCP-VD, FAZ and CCF measurements.

CONCLUSIONS

Our findings demonstrating that CoronaVac vaccine did not affect retinal vascular density in the early period, but it caused alterations in the retrobulbar blood flow.

Evaluation of the impact of childhood obesity on retrobulbar hemodynamics and retinal microvasculature

OBJECTIVE

To evaluate changes in retrobulbar ocular blood flow parameters by using Colour Doppler Imaging (CDI) and changes in foveal microvasculature by using Optical Coherence Tomography Angiography (OCTA) in pediatric obese patients and to compare them with a group of healthy children.

METHODS

Children diagnosed with obesity without hypertension and diabetes (39 subjects, obese group) and age-matched healthy controls (26 subjects, control group) underwent CDI and OCTA imaging. Peak systolic velocity, end-diastolic velocity and resistivity index from ophthalmic, central retinal and posterior ciliary arteries on CDI; superficial and deep capillary plexus vascular density and foveal avascular zone area on OCTA imaging were obtained in each group. Central foveal and subfoveal choroidal thicknesses were also measured. CDI and OCTA parameters were compared between two groups.

RESULTS

Peak systolic and end-diastolic velocities were found to be significantly lower in obese children than in controls in all three examined arteries (p < 0.05). Resistivity index values were similar between the groups. OCTA imaging did not reveal significant changes in superficial and deep capillary plexus vascular densities and foveal avascular zone area across analysed retinal regions between the groups. Subfoveal choroid was thicker in obese group than in control group (325.89 ± 52.77 µm vs. 304.52 ± 21.76 µm, p = 0.04).

CONCLUSION

An apparent decrease was present in retrobulbar hemodynamics in obese children. This arises the possibility of early ocular macrovascular compromise rather than retinal microvascular impairment in childhood obesity.

Short-term changes in retinal and choroidal relative flow volume after anti-VEGF treatment for neovascular age-related macular degeneration

The effects of anti-vascular endothelial growth factor (anti-VEGF) agents on the native ocular vasculature are poorly understood. This pilot study aimed to assess short-term changes in retinal and choroidal perfusion after anti-VEGF treatment for neovascular exudative age-related macular degeneration (nAMD) using the relative flow volume (RFV) parameter derived from laser speckle flowgraphy. Ten treatment-naïve nAMD patients underwent measurements of mean, maximum, minimum, and differential RFV within a retinal arteriolar segment and a choroidal vessel segment outside the neovascular area. Measurement of retinal RFV (rRFV), choroidal RFV (cRFV), and subfoveal choroidal thickness (SCT) was repeated 9 and 35 days after a single anti-VEGF injection. The treatment caused a statistically significant decrease in the mean rRFV, mean cRFV, and SCT during the follow-up (p < 0.05). At the intermediate visit, the mean cRFV and SCT were − 17.6% and − 6.4% compared to baseline, respectively. However, at the final measurement, the mean cRFV was not different from the baseline value, which indicated waning of the anti-VEGF effect. In conclusion, a single anti-VEGF injection in treatment-naïve nAMD resulted in a decrease in retinal arteriolar and choroidal perfusion, according to the RFV parameter, which is a promising tool to simultaneously assess retinal and choroidal perfusion changes in response to anti-VEGF therapy.

Short-term effect on the ocular circulation induced by unilateral intravitreal injection of aflibercept in age-related maculopathy

Purpose

Intravitreal injection of anti‐vascular endothelial growth factor (anti‐VEGF) is the standard treatment for neovascular age‐related macular degeneration (AMD). As VEGF is a physiological key player for regulating retinal vascular tone, questions have been raised whether the application of anti‐VEGF could induce alterations in ocular perfusion.

Methods

The study included 20 eyes from 20 Caucasian patients with unilateral neovascular AMD and 20 fellow eyes. All eyes were treated with standard intravitreal injection of aflibercept (IVA). Measurements of blood flow at the optic nerve head (ONH) and the choroid were performed with laser speckle flowgraphy (LSFG). The intraocular pressure (IOP), systolic and diastolic blood pressure, heart rate, mean arterial pressure (MAP) and ocular perfusion pressure (OPP) were analysed. Measurements were performed at baseline and repeated immediately after the injection and 30 and 45 min later.

Results

Mean time between injection of aflibercept and first follow‐up was 8:56 ± 4:25 min. The injection led to significant rise in IOP. In the injected eyes, mean blur rate (MBR, i.e. a relative measure of perfusion and the main outcome parameter of LSFG) within the major vessels of the ONH as well as at the entire ONH region decreased significantly (p < 0.001). No change in MBR was observed in the fellow eye. Choroidal blood flow was maintained stable in both eyes.

Conclusion

Intravitreal injection of aflibercept (IVA) led to a short‐term reduction in perfusion only in the treated eye. This was independent from IOP, indicating a direct pharmacological effect. No changes in choroidal perfusion were observed during the first 45 min after the injection.

Choroidal blood flow after the first intravitreal ranibizumab injection in neovascular age-related macular degeneration patients

PURPOSE

To analyse choroidal blood flow (ChBF) changes after the first intravitreal ranibizumab injection in naïve, age-related macular degeneration (ARMD) patients.

METHODS

Subfoveal ChBF was assessed by laser Doppler flowmetry (LDF) in newly diagnosed ARMD patients. Both treated and untreated eyes were assessed in each subject at each visit before the first intravitreal ranibizumab injection as well as 24 hr (day 1) and 7 days after (day 7). Central macular thickness (CMT), best-corrected visual acuity (BVCA), systemic haemodynamic parameters and LDF parameters were evaluated at each visit. Nonparametric tests were used to compare data between visits and between treated and untreated eyes.

RESULTS

Seventeen ARMD patients were included (12 women and five men, 78 ± 8 years old). At day 7 postintravitreal ranibizumab injection, the normalized choroidal blood velocity (ChBVel) change in the treated eye group was significant (-10.2%; p = 0.006). The choroidal blood volume (ChBVol) did not change significantly after intravitreal injection of ranibizumab. There was a trend for a reduction in ChBF at day 7 (-9.1%, p = 0.08). The sensitivity of the experiment was 12% for ChBVel, 16% for ChBVol and 9% for ChBF.

CONCLUSION

In conclusion, the laser Doppler technique provides feasible and noninvasive measurements of blood flow parameters before and after intravitreal injection of antivascular endothelial growth factor (anti-VEGF) in patients with exudative ARMD. Choroidal blood velocity decreased as early as 7 days after intravitreal ranibizumab injection, suggesting a vasoconstriction effect of anti-VEGF in large choroidal vessels in front of choriocapillaris (the site of LDF measurement).

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Effect of intravitreal ranibizumab on the ocular circulation of the untreated fellow eye

Purpose

To evaluate the effects of unilateral intravitreal ranibizumab (IVR) on the ocular circulation of the fellow eyes.

Methods

Fifteen eyes of 15 patients with macular edema (average age 69.6 ± 11.8 years) were studied. Eleven eyes had diabetic macular edema (DME) and four eyes had macular edema associated with a branch retinal vein occlusion. Each eye received 0.5 mg of IVR. The blood circulation on the optic nerve head of the treated and untreated eyes were determined by laser speckle flowgraphy (LSFG, Softcare Co., Ltd) before, 1 day, and 1 week after the IVR. The mean blur rate (MBR) and the relative changes of the MBRs determined as dMBR(%) = 100−(MBR before/MB after) × 100) were evaluated. The central macular thickness (CMT) and the rate of reduction in the thickness (dCMT = 100−(CMT before/CMT after) × 100) were also evaluated.

Results

The mean dMBR was significantly higher in the treated eyes than the untreated eyes at 1 day (−16.4 ± 17.0% vs 2.31 ± 19.3%) and at 1 week (−12.0 ± 14.6% vs 4.50 ± 25.9%) after the IVR (P = 0.02, paired t tests).

Conclusion

These findings indicate that if ranibizumab enters the systemic circulation, the concentration is not high enough to affect the ocular circulation of the fellow eyes.

Effect of intravitreal aflibercept (Eylea®) on retrobulbar hemodynamics in patients with neovascular age-related macular degeneration

PURPOSE

To investigate the short-term effect of single intravitreal aflibercept injection on retrobulbar blood flow in patients with neovascular age-related macular degeneration (nAMD).

METHODS

Twenty eyes of 20 patients with nAMD scheduled for single intravitreal aflibercept (Eylea^®) injection and 20 fellow eyes (uninjected) were enrolled in this prospective interventional study. The hemodynamic parameters of the ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary artery (PCA) comprising peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) were measured by using color Doppler ultrasonography (CDU) in both injected and uninjected fellow eyes at baseline and 1 week after the injection.

RESULTS

The measured first-week values of PSV and EDV in the CRA, OA and PCA showed a statistically significant reduction when comparing baseline values in both injected and uninjected fellow eyes (p = 0.0001). Also, it was found a significant increase in the post-injection RI values of all the CRA, OA, PCA in injected eye and OA in the uninjected eye (p = 0.0001). There was any significant difference between pre- and post-injection RI values of the CRA and PCA in the fellow eyes (p = 0.137, p = 0.736, respectively).

CONCLUSION

Single intravitreal administration of aflibercept alters retrobulbar blood flow velocities (BFVs) in both injected and uninjected fellow eyes in the short-term period.

Effect of anti-VEGF drugs combined with photodynamic therapy in the treatment of age-related macular degeneration

We analyzed the effects of anti-vascular endothelial growth factor (VEGF) drugs combined with photodynamic therapy (PDT) in the treatment of age-related macular degeneration (AMD). Ninety-six cases (192 eyes) of AMD were included in this study and randomly divided into the observation group and control group (n=48 cases per group). The control group was administered the treatment of Lucentis intravitreal injection alone and the observation group was administered Lucentis combined with PDT. The therapeutic effects were compared. The best corrected visual acuity of patients in the two groups increased gradually after treatment. Patients in the observation group had a significantly higher visual acuity when compared to the control group 1 and 6 months post-operation. The differences were statistically significant (P<0.05). The proportion of patients with vision improvement in the observation group was higher than that in the control group from 1 to 6 months; differences were statistically significant (P<0.05). Through detection by color Doppler ultrasound within 6 months after treatment, we observed that the peak systolic velocity and arterial end diastolic velocity of retrobulbar optic nerve bitemporal PCA of the observation group were higher than those of the control group. The values of arterial resistance index and pulsatility index of the observation group were lower than those of control group. The differences were statistically significant (P<0.05). Six months after treatment, the value of central foveal thickness of the observation group was lower than that of the control group, the value of mean sensitivity of visual field parameter 10° and 4° was higher in the observation group than in the control group, and the absolute value of mean defects in the observation group were lower than that of the control group. In summary, the differences were statistically significant (P<0.05). Anti-VEGF drugs combined with PDT can optimize the overall vision of patients with AMD, improve hemodynamic parameters and reduce visual field defects.

The effect of intravitreal vascular endothelial growth factor on inner retinal oxygen delivery and metabolism in rats

Vascular endothelial growth factor (VEGF) is stimulated by hypoxia and plays an important role in pathologic vascular leakage and neovascularization. Increased VEGF may affect inner retinal oxygen delivery (DO2) and oxygen metabolism (MO2), however, quantitative information is lacking. We tested the hypotheses that VEGF increases DO2, but does not alter MO2. In 10 rats, VEGF was injected intravitreally into one eye, whereas balanced salt solution (BSS) was injected into the fellow eye, 24 h prior to imaging. Vessel diameters and blood velocities were determined by red-free and fluorescent microsphere imaging, respectively. Vascular PO2 values were derived by phosphorescence lifetime imaging of an intravascular oxyphor. Retinal blood flow, vascular oxygen content, DO2 and MO2 were calculated. Retinal arterial and venous diameters were larger in VEGF-injected eyes compared to control eyes (P < 0.03), however no significant difference was observed in blood velocity (P = 0.21). Thus, retinal blood flow was greater in VEGF-injected eyes (P = 0.007). Retinal vascular PO2 and oxygen content were similar between control and VEGF-injected eyes (P > 0.11), while the arteriovenous oxygen content difference was marginally lower in VEGF-injected eyes (P = 0.05). DO2 was 950 ± 340 and 1380 ± 650 nL O2/min in control and VEGF-injected eyes, respectively (P = 0.005). MO2 was 440 ± 150 and 490 ± 190 nL O2/min in control and VEGF-injected eyes, respectively (P = 0.31). Intravitreally administered VEGF did not alter MO2 but increased DO2, suggesting VEGF may play an offsetting role in conditions characterized by retinal hypoxia.

Effect of intravitreal bevacizumab on retrobulbar blood flow of patients with diabetic macular edema

PURPOSE

To determine the effect of intravitreal bevacizumab on retrobulbar blood flow of patients with diabetic macular edema.

METHODS

Peak systolic velocity, end-diastolic velocity, resistance, and pulsatility indices of central retinal artery (CRA), nasal posterior ciliary artery (NPCA), temporal posterior ciliary artery (TPCA), and ophthalmic artery (OA) were assessed by color Doppler ultrasonography in injected and uninjected eyes of 37 patients at baseline and at day 1 and day 7 after the injection.

RESULTS

At day 1 after the injection, peak systolic and end diastolic velocities of the CRA and NPCA in the injected eyes and peak systolic velocity of NPCA in the uninjected eyes decreased significantly (p&lt;0.05, p = 0.025, respectively). Peak systolic and end diastolic velocities were not significantly different in the injected and uninjected eyes at day 7 after the injection (p&gt;0.05). In the injected eyes, there was no significant change in resistance and pulsatility indices (p&gt;0.05), but a decrease in resistance index of NPCA and resistance and pulsatility indices of TPCA occurred in uninjected eyes at day 7 after the injection (p = 0.016, p = 0.023, and p = 0.025, respectively).

CONCLUSIONS

Intravitreal bevacizumab affects retrobulbar blood flow in injected and uninjected eyes of patients with diabetic macular edema.

Blood flow velocity measured using the Retinal Function Imager predicts successful ranibizumab treatment in neovascular age-related macular degeneration: early prospective cohort study

PURPOSE

Anti-VEGF treatment has a potent vasoconstrictive effect. Early changes of retinal blood flow velocity (RBFV) measured using the Retinal Function Imager (RFI) combined with indicators of vascular status may help in predicting the visual outcome 1 month post injection in patients with neovascular age-related macular degeneration (nvAMD) under ranibizumab treatment. To develop a simple prediction model based on the change in RBFV 3 days post injection and indicators of a patient's vascular status to assess the probability of a successful visual outcome 1 month post injection.

METHODS

RBFV measured using RFI were prospectively collected pre-injection and 3 days post injection in 18 eyes of 15 patients. Indicators of vascular status (history of hypertension, diabetes mellitus without retinal affection, and smoking) were assessed by medical history. By univariate analyses, parameters associated with visual outcome were weighted (-1 to 6 points). A multivariate logistic regression model with the categorized visual outcome parameter (≥0 letters gained after 1 month) as the dependent variate and the sum score as the independent variate (continuous scale) was used to estimate the score value-specific probabilities of letters gained ≥0 1 month post injection.

RESULTS

The indicators of vascular status negatively influenced the likelihood of a letter gain ≥0 whereas an increase in the arterial RBFV strongly increased it. The area under the receiver operating characteristics curve for these parameters investigated was 0.71 (95% CI: 0.43-1.00).

CONCLUSION

Changes in the arterial RBFV following 3 days after ranibizumab injection combined with three indicators of the vascular status identified nvAMD patients with favorable visual outcome accurately.

Recent advances in the management of neovascular glaucoma

The development of anti-vascular endothelial growth factor (VEGF) molecules has expanded the range of available treatment options for many ocular diseases, including neovascular glaucoma (NVG). A number of studies have explored the use of anti-VEGF agents as stand-alone or adjunctive treatment for NVG. Although no large, prospective, randomized trials have been performed to date, the growing body of knowledge suggests that anti-VEGF agents are effective at reversing iris and angle neovascularization and lowering intraocular pressure in patients with NVG. Response to a single injection is typically temporary; therefore, laser or incisional surgery is still necessary in most cases. Future research is needed to determine the optimal agent, dose, route of administration, and timing of treatment either as monotherapy or coupled with other medical and/or surgical interventions.

Impact of intravitreal triamcinolone acetonide versus intravitreal bevacizumab on retrobulbar hemodynamic in patients with diabetic macular edema

PURPOSE

To evaluate and compare retrobulbar hemodynamic changes measured with color Doppler imaging (CDI) in diabetic patients receiving intravitreal triamcinolone acetonide (IVTA) versus bevacizumab.

METHODS

Patients with diffuse diabetic macular edema were assessed prospectively by CDI following intravitreal injection of triamcinolone acetonide (group I, 12 eyes) versus bevacizumab (group II, 14 eyes). CDI was used to measure the peak systolic velocity (PSV), end diastolic velocity (EDV) and the resistive index (RI) of the central retinal artery (CRA), ophthalmic artery (OA) and posterior ciliary arteries (PCA) one day preoperatively and one week postoperatively.

RESULTS

In group I, EDV of OA and CRA decreased significantly (p = 0.007 and 0.018, respectively). The PSV and RI of PCA decreased significantly (p = 0.035 and 0.002, respectively). In group II, both the PSV and EDV of the CRA decreased significantly (p = 0.000). Comparing the percentage of change in both groups, PSV of the CRA decreased significantly in group II (p = 0.034), while IVTA has more significant effect on the ophthalmic artery hemodynamic parameters as EDV decreased and RI increased significantly (p = 0.045 and 0.043, respectively)

CONCLUSION

Intravitreal injections of triamcinolone acetonide and bevacizumab have a significant effect on the ocular hemodynamic. The effect of bevacizumab is statistically significant on the PSV of CRA compared to IVTA.

Adverse events associated with intraocular injections of bevacizumab in eyes with neovascular glaucoma

BACKGROUND

Bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF), has been reported to cause rapid regression of anterior segment neovascularization in eyes with neovascular glaucoma when administered intraocularly. Several studies have reported the safety profile of intravitreal injections of bevacizumab in patients with various retinal pathologies. We investigated the occurrence of adverse events associated with intraocular bevacizumab injections in patients with neovascular glaucoma.

METHODS

We retrospectively reviewed the charts of 84 eyes of 70 patients with neovascular glaucoma that received intraocular bevacizumab injections to treat anterior segment neovascularization for the first time at Kanazawa University Hospital.

RESULTS

The mean age of the patients was 63.5 ± 13.3 years (± standard deviation; range, 31-85 years). The underlying retinal diseases were proliferative diabetic retinopathy in 58 eyes (69%), central retinal vein occlusion in 17 eyes (20%), ocular ischemic syndrome in four eyes (5%), central retinal artery occlusion in three eyes (4%), branch retinal vein occlusion in one eye (1%), and radiation retinopathy in one eye (1%). The total number of intraocular injections of bevacizumab was 116 (1.4 ± 0.8 injections/eye, range, one to five injections/eye). Most were intravitreal injections (1.25 mg/0.05 ml; 115 injections, 99%). No cases had marked inflammation, lens injuries, marked vitreous hemorrhage, retinal detachment, or endophthalmitis. However, two eyes (2%) of two cases (3%) developed central retinal artery occlusion 3 or 4 days after bevacizumab injection. Both were among four eyes (i.e., 50%) with ocular ischemic syndrome. One of them had received an intracameral injection of bevacizumab (0.75 mg/0.03 ml) before the adverse event. No cases experienced systemic side-effects including myocardial infarction and cerebrovascular accidents within 3 months after bevacizumab injection.

CONCLUSIONS

Central retinal artery occlusion may be a relatively common complication following intraocular injection of anti-VEGF agents in patients with neovascular glaucoma, particularly when it was associated with ocular ischemic syndrome. Since visual prognosis of central retinal artery occlusions is usually poor, intraocular injection of anti-VEGF agents should be performed with thoughtful consideration of the risks and benefits of the treatment, and with a strict follow-up examination, especially in high-risk patients.

The effect of intravitreal bevacizumab (Avastin) injection on retinal blood flow velocity in patients with choroidal neovascularization

Purpose

To study the short-term effects of intravitreal bevacizumab (Avastin) on retinal blood flow velocity and compare them to clinical outcomes assessed by optical coherence tomography (OCT) and tests of visual acuity.

Methods

The Retinal Function Imager (RFI) was used noninvasively and quantitatively to measure retinal blood flow velocity. Eight patients receiving intravitreal injection of Avastin for choroidal neovascularization (CNV) were included in this study. All were imaged by the RFI preinjection and 1 and 7 days postinjection. Visual acuity (VA) and OCT were recorded preinjection and 1 month postinjection. Comparisons were performed using paired Student t test and correlation using Spearman rank test.

Results

A good correlation was found between the 1-month change in VA and OCT measurements and the short-term change induced in blood flow velocity. Arterial and venous velocity changes 1 day after the injection correlated with the VA change (p<0.05). The 1-day arterial velocity changes correlated with total macular volume (p=0.02) and venous velocity changes correlated to central macular thickness (p=0.04).

Conclusions

The RFI provides a noninvasive technique to assess early hemodynamic responses to intravitreal injection of Avastin. These early changes may prove important for better understanding of the mechanism underlying this treatment and serve as a quantitative marker for treatment optimization.