Abstract
Purpose: :
To determine if there is a reduction in the frequency and severity of side effects during digital intravenous fluorescein angiography (IVFA) using 2ml of 10% sodium fluorescein (NaFl) as opposed to the standard dose of 5ml of 10% NaFl. The study design incorporated evaluations of image quality and study utility for IVFA’s performed utilizing the reduced volume of fluorescein versus the standard volume in the context of modern high–resolution digital fluorescein angiography.
Methods: :
A prospective study of 1200 patients was initiated. An interim analysis was carried out after 140 patients had been randomized to either the 2ml or the 5ml NaFl group. A masked observer carried out evaluation for adverse events in these two groups. Standard IVFA technique was employed and photographers completed a rating scale indicating the difficulty of performing the photography for each of the study patients. Ophthalmologists were kept blinded to the dose of NaFl administered and used a rating scale to grade the quality of each of the angiograms.
Results: :
The interim analysis of the data revealed a statistically significant reduction in the quality of angiograms where 2ml of NaFl was administered, necessitating the termination of the study. When all three photographers were combined, gradings were significantly different between the two study groups with the 2ml NaFl group inferior (p value= .0012). With all three ophthalmologists combined, the average grading of the quality of the IVFA’s for the 2ml group was also inferior to that for the 5ml group (p value= .0025). All calculations were adjusted for butterfly gauge, age, pupil size, test length, and where appropriate, ophthalmologist or photographer. A total of three minor adverse events occurred in the 140 patients. Patients randomized to the 5ml NaFl group experienced all three of these events. No statistically relevant conclusions could be obtained from this limited group.
Conclusions: :
This study has shown that 2ml of NaFl for intravenous fluorescein angiography produces inferior quality digital images compared to that produced by the standard dose of 5ml of NaFl. The potential reduction in adverse events associated with the lower dose of NaFl becomes unimportant in light of this significant finding.
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • imaging/image analysis: clinical • retina