Abstract
Purpose: :
To evaluate the effect of high dose niacin (nicotinic acid) with or without topical prednisolone acetate on the course of initially nonischemic CRVO, HRVO and BRVO.
Methods: :
A prospective, nonrandomized pilot study of nicotinic acid as a possible vasodilator, with or without a topical steroid for reduction of macular edema, was undertaken in patients with initially nonischemic retinal vein occlusions. Forty-five consecutive patients with worsening CRVO, HRVO or BRVO were placed on lipid lowering doses of nicotinic acid (target dose 500mg TID, range 1-2 grams/day) under an internist's supervision. Prednisolone acetate eye drops were used QID in the affected eye of 29 subjects. Follow-up included examination, OCT and fundus photos. Primary outcome measures were changes in vision and central macular thickness (CMT).
Results: :
Over time, usually a few months, retinal hemorrhages subsided, as did vascular congestion and CMT in many, but not all patients. Some patients improved on nicotinic acid alone, whereas others only improved when combined with the topical steroid. Vision improved subjectively in the form of a sense of expanded field as hemorrhages resolved. This was followed in most eyes with improved visual acuity as macular edema subsided. In several instances, inadvertent withdrawal of either nicotinic acid or topical steroid drops was followed by deterioration, which resolved after restoring treatment, suggesting reversibility of effect. There were a few nonresponders, or steroid responders who deteriorated with withdrawal of the topical steroid. They were offered bevacizumab as adjunctive treatment, which led to clinical improvement in some, but not all cases. Eyes which eventually became ischemic, rarely developed significant rubeosis.
Conclusions: :
Nicotinic acid, alone or combined with topical prednisolone acetate, was associated with clinical improvement in nonischemic CRVO, HRVO and BRVO. Many eyes showed improved visual acuity, which persisted over time. Nicotinic acid induces vasodilation by means of a prostaglandin mediated release of nitric oxide, a potent vasodilator. Perhaps the vasodilation effect contributes to earlier collateral vessel formation. Dilation of the choroid might also improve outer retinal oxygenation, thereby better preserving photoreceptors. The topical steroid appears to hasten the resolution of macular edema, compared to the use of nicotinic acid alone.
Clinical Trial: :
www.clinicaltrials.gov NCT00493064
Keywords: vascular occlusion/vascular occlusive disease • retina • blood supply