Abstract
Purpose: :
Cases of macular ischemia after intravitreal bevacizumab injections have been reported. This may be caused by retinal vascular narrowing after injection. This study examines the effects of a single intravitreal injection of bevacizumab on the diameter of retinal arteries and veins in both the injected and the contralateral eye in a diverse clinic population.
Methods: :
A retrospective chart review included 60 eyes from 30 consecutive patients who received a single intravitreal injection of bevacizumab (Avastin®) (1.25 mg/0.05 mL). In both the injected eye and the contralateral eye, two zones, defined as 0.5 and 1 disc diameter (Z1 and Z2, respectively) away from the optic disc margin were identified on fluorescein angiogram during the venous phase. Retinal artery diameters and retinal vein diameters were measured at distinctively identifiable locations in both Z1 and Z2 using a built-in ruler tool in VISUPAC Fundus Imaging Software (Zeiss). Data were collected for each specific vessel one month prior to treatment and one month after treatment. Significance was calculated using the paired t-test.
Results: :
Of the 30 patients, there were 17 Hispanics, 7 Asians, 4 Blacks, and 2 Caucasians. Diagnoses at the time of injection included 22 diabetic retinopathy, 5 CRVO, 1 BRVO, 1 CSCR, and 1 ARMD. Retinal artery measurements taken at Z1 one month after treatment showed a statistically significant reduction in vessel diameter from 0.14 +/- 0.02 mm to 0.13 +/- 0.02 mm (p=0.0091). In the contralateral eyes, retinal artery measurements taken at Z1 one month after treatment showed a decreasing trend from 0.14 +/- 0.02 mm to 0.14 +/- 0.03 mm (p=0.1250). There were no significant changes in diamters of Z2 arteries or any veins in the injected or contralateral eyes.
Conclusions: :
We demonstrated a statistically significant reduction in the retinal artery diameters at 1 month after injection with bevacizumab. This reduction in vessel diameter may play a role in the development of macular ischemia. Additionally, the decreasing trend in the contralateral eye could suggests there may also be a weak systemic effect on the non-injected eye. As many of these patients are at risk for ischemia, further study is warranted on the effects of multiple bevacizumab injections with greater length of follow-up.
Keywords: blood supply • imaging/image analysis: clinical • injection