Serial bevacizumab injections and laser photocoagulation for macular edema associated with a retinal artery macroaneurysm

Abstract

An 84-year-old female with a history of hypertension and dyslipidemia was referred for a retinal artery macroaneurysm with exudation that had extended into the macula. She underwent a total of six injections of bevacizumab, with some improvement in visual acuity and retinal thickness. Due to persistent macular edema, focal laser photocoagulation was performed around the macroaneurysm. The vision remained at 20/30 during 20 months of follow up. Although anti-vascular endothelial growth factor therapy may improve vision and decrease retinal thickness in retinal artery macroaneurysm, recalcitrant cases may be treated with laser photocoagulation to seal the leaking vessel.

Keywords:

• bevacizumab
• laser
• retinal artery macroaneurysm

Introduction

Retinal artery macroaneurysms (RAMs) are rare, acquired dilatations of the retinal arterial vasculature, usually within the first three branches of the arteriolar tree.¹ The incidence is estimated to be approximately 1 in 4,500 people over the age of 40.² Hypertension and older age lead to hyaline degeneration of the vascular walls, loss of autoregulatory tone and elastic recoil, and arterial dilatation.³

Approximately 8%–25% of RAMs will undergo spontaneous involution. Even with submacular hemorrhage, up to 37% of patients will have better than 20/40 visual acuity without treatment.⁴ However one third of patients will develop vascular leakage and retinal edema and may need treatment.⁵

Case report

An 84-year-old female with a past medical history of hypertension and dyslipidemia was referred for progressively decreasing visual acuity in the left eye. She had no history of diabetes. On initial examination, her visual acuity was 20/30 in both eyes. Dilated fundus examination and fluorescein angiography of the left eye revealed a superotemporal retinal arterial macroaneurysm, with surrounding circinate exudates involving the fovea (Figures 1 and 2). The right eye was normal.

Figure 1 Fluorescein angiography and fundus photographs.

Notes: (A) Fluorescein angiogram demonstrating a superotemporal macroaneurysm with surrounding leakage and blockage by blood. (B) Fundus photograph of the superotemporal RAM with surrounding exudation involving the macula. Best-corrected visual acuity was 20/30. (C) After initial improvement in vision and macular edema with intravitreal bevacizumab, the patient was observed for a period of 3 months. The hemorrhage and edema worsened, and the visual acuity worsened to 20/60. Additional anti-VEGF was given, and the vision improved to 20/30. (D) After 19 months of anti-VEGF therapy, the edema worsened, and the vision again decreased to 20/60. The decision was made to undergo laser photocoagulation around the RAM. (E) After laser photocoagulation, the RAM is occluded and the exudates have mostly resolved.
Abbreviations: RAM, retinal artery macroaneurysm; VEGF, vascular endothelial growth factor.

Figure 2 Progression on OCT.

Notes: (A) Cirrus OCT of the exudates and edematous retinal thickening surrounding the superotemporal retinal artery macroaneurysm. (B) Initial OCT of the fovea demonstrating cystoid macular edema and a CFT of 312 μm. (C) OCT demonstrating recurrence of the macular edema after intravitreal bevacizumab. CFT was 349 μm. (D) Despite initial improvement in visual acuity and the retinal thickness improved, then worsened again after 14 months of bevacizumab. The CFT was 520 μm. (E) OCT of the macula after definitive laser therapy, with a reduction of retinal thickness to 241 μm.
Abbreviations: CFT, central foveal thickness; OCT, optical coherence tomography; ILM, Internal limiting membrane; RPE, retinal pigment epithelium; S, superior; I, inferior; N, nasal; T, temporal.

The patient was observed initially, but the edema increased and her vision deteriorated to 20/60. An intravitreal injection of 1.25 mg of bevacizumab improved the vision to 20/30. The patient was observed for 3 months, but the vision worsened again to 20/60, with increased edema and exudates on optical coherence tomography. She was observed for 3 months, but due to recurrent leakage, she ultimately received a total of six injections of intravitreal bevacizumab every 1 month to 3 months. Her vision gradually improved back to 20/30.

Fourteen months after initial presentation, her vision deteriorated again to 20/60. The decision was made to perform laser photocoagulation around the macroaneurysm. Argon laser at a setting of 400 mW and 200 μm spot size was applied around the RAM. The RAM occluded, and on follow-up examination 6 months later, the patient’s vision has remained at 20/30.

Discussion

The first report of laser photocoagulation to treat exudative retinal artery macroaneurysm was published in 1976 by Dr Donald Gass and colleagues.⁶ In a study of 27 patients with symptomatic RAM, half of the patients underwent argon laser therapy and the remaining half was observed. The vision in both groups improved, but the laser group experienced a greater gain.⁷ Approximately 16%–27% of RAMs occlude with lasers, but there is a risk of vascular occlusion, early increase in exudates from selective reabsorption of fluid, arteriovenous shunts, macular pucker, and scotomas.^7,8 Other treatment options for RAMs include yellow dye laser and indocyanine green dye-enhanced photocoagulation.^9,10

Anti-vascular endothelial growth factor (VEGF) therapy has recently been reported in the treatment of patients with exudative or hemorrhagic RAMs. Chanana and Azad¹¹ published the first case report in 2009, and subsequent case reports have shown encouraging results (Table 1).^12–19 Cho et al¹⁸ described 23 patients with RAMs who were either observed or received intravitreal bevacizumab. Both groups experienced statistically significant improvements in visual acuity and central macular thickness, but the bevacizumab group regained vision faster. A larger, prospective study of 38 eyes with hemorrhagic and exudative RAMs underwent three monthly injections of bevacizumab, with the vision and retinal thickness improving in both groups.¹⁹

Table 1 Literature review of anti-VEGF use in the treatment of retinal artery macroaneurysms

Author	Year of publication	Treatment	Number of patients	Pre-BCVA (Snellen equivalent)	Post-BCVA (Snellen equivalent)	Retinal thickness (μM)	Mean number of injections	Follow-up (in months)
Chanana and Azad^Citation11	2009	Bevacizumab	1	20/400	20/50	607 to 173	2	1.5
Jonas and Schmidbauer^Citation12	2010	Bevacizumab	1	20/400	20/200	“Completely absorbed”	1	3
Javey et al^Citation13	2010	Bevacizumab	1	20/400	20/20	–	2	12
Wenkstern and Petersen^Citation14	2010	Ranibizumab + focal laser	1	20/50	20/25	510 to 148	2	5
Golan et al^Citation15	2011	Bevacizumab	1	20/160	20/20	364 to 248	2	13
Tsakpinis et al^Citation16	2011	Bevacizumab	1	20/60	20/25	–	2	39
Zweifel et al^Citation17	2013	Bevacizumab + ranbizumab	10	20/100	20/50	366 to 266	3	6.1
Cho et al^Citation18	2013	Bevacizumab	23	20/80	20/60	384 to 265	1.42	10.8
Pichi et al^Citation19	2013	Bevacizumab	38	20/75	20/25	520 to 214	3	3

Abbreviation: BCVA, best-corrected visual acuity.

The role of VEGF and the mechanism of action of anti-VEGF therapy in RAMs are not fully understood. In a study that compared the VEGF levels in 500 μL vitreous samples from patients with vitreous hemorrhage from nondiabetic etiologies (including four patients with RAM) with those from patients with proliferative diabetic retinopathy, the VEGF levels were significantly lower in the former than in the latter groups (2.75 pg/mL vs 821 pg/mL, respectively).²⁰ However, these were small vitreous samples obtained up to 3 weeks after the initial hemorrhage and may not have been representative of the vitreous and microenvironment around the RAM.

The role of VEGF in intracranial aneurysms and other biological systems has been more clearly elucidated. In intracranial aneurysms, VEGF levels were found to be significantly higher than the levels in controls.²⁰ In particular, patients with intracranial aneurysms had higher expressions of VEGF receptor 2 (VEGFR2) and lower levels of VEGF receptor 1 (VEGFR1). VEGFR1 is associated with angiogenesis, while VEGFR2 is associated with thrombosis.²¹ Bevacizumab has been shown to decrease VEGFR1 levels and to increase VEGFR2 levels to normal levels in cancer cells.²² In the circulatory system, platelets produce VEGF, which stimulates nitrous oxide production, resulting in vasodilation.²¹ Inhibition of VEGF may decrease leakage of fluid and exudates through the endothelium. In mice studies, bevacizumab decreases bleeding time and increases coagulation.²³ Thus, VEGF inhibition may block angiogenesis, decrease binding of the prothrombotic VEGFR2, and decrease vascular permeability.

In conclusion, the majority of RAMs can be observed, but intervention may be necessary in cases of persistent or recurrent macular edema from exudative or hemorrhagic RAMs. Our patient’s RAM was initially observed, but continued leakage prompted further therapy.

Anti-VEGF injections have shown promise in improving visual acuity and hastening resolution of macular edema in RAM;⁵ however, most of the previously published cases had relatively short follow-up. Our case has one of the longest follow-ups with the most number of anti-VEGF treatments, but the patient continued to have leakage into the macula. The potential benefits of anti-VEGF treatment must be carefully weighed against the potential risk of infection from serial injections. Laser photocoagulation remains a viable treatment option in cases of macular edema secondary to RAM.

Disclosure

The authors report no conflicts of interest in this work.