Purpose:
To analyze the functional and anatomical response to intravitreal anti-VEGF therapy with bevacizumab (Avastin®) in patients with exudative age related macular degeneration (AMD) before and after treatment of obstructive sleep apnea (OSA).
Methods:
12 patients with untreated OSA were treated with intravitreal bevacizumab (1.25 mg/0.05 ml) injections at every 6 weeks for clinical and angiographic evidence of exudative AMD. Clinical examinations and OCT at 6 week intervals were used to assess the anatomical and functional outcome for up to 90 weeks. Continuous positive airway pressure therapy (CPAP) was initiated after 36±12 weeks. Change in Snellen and in logMAR visual acuity during the follow-up period was plotted over time to gauge the functional effect of anti-VEGF treatment. Anatomical effect of treatment was assessed using the Standardized Volumetric Change Index (SVCI) curve, which involves OCT thickness data normalized for the diurnal variation at each sector using an age-matched cohort. Using this curve, time-to-maximum effect of the anti-VEGF treatment, and time-to-anatomical stabilization were calculated.
Results:
Throughout the follow-up period of 81 ± 9 (72-90) weeks patients received 10 ± 4 (6-14) bevacizumab injections. Prior to CPAP, fluctuations of SVCI fit to a sine curve (r=0.91, p=0.03) with modest fluctuations with a maximum of 6.0 ± 5.1 % decrease in SVCI at 6.9 weeks after the first bevacizumab injection. Subsequent injections did not yield in any further significant anatomic effect. After CPAP, fluctuations of SVCI fit to a significantly different (P<0.01) sine curve (r=0.99, p=0.02) with marked fluctuations with a maximum of 50.0 ± 10.5 % decrease in SVCI at 42 weeks after the first bevacizumab injection. Initial visual acuity (20/60 ± 20/16) was decreased significantly despite therapy to reach a final visual acuity of 20/100 ± 20/32 at 82nd week.
Conclusions:
Untreated OSA hinders the response of exudative AMD to pharmacotherapy with anti-VEGF. Treatment of OSA with CPAP yields a subsequent impressive anatomical response, however functional improvement does not follow. Indentifying and treating underlying OSA earlier in the management of exudative AMD may yield better functional outcomes.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: risk factor assessment • injection