Predictive Features of Polypoidal Choroidal Vasculopathy Detected Using Fluorescein Angiography
Polypoidal choroidal vasculopathy (PCV) and age-related macular degeneration (AMD) share common clinical features but have distinct clinical courses and visual prognosis. PCV is believed to be indistinguishable from AMD using flurorescein angiography (FA). However, when indocyanine green angiography (ICGA) is contraindicated or unavailable, ophthalmologists may need to make a diagnosis based on FA. We describe distinguishing FA features of PCV compared to neovascular AMD and determine the predictive value of these features.
FA and ICGA from a prospective, multi-center study of 78 patients (60 PCV and 18 AMD) were independently graded using standardized diagnostic algorithms. Predictive features for PCV on FA were analyzed using multiple logistic regression.
Patients with PCV had predominantly occult choroidal neovascularisation (CNV) on FA (90.0% vs. 73.3% of AMD patients). Classic CNV was less frequent (5.0% vs. 22.2%) and was significantly smaller in PCV (0.09 vs. 0.65 mm2, p=0.005). Using logistic regression analysis, the most predictive features for PCV were the presence of a nodular hyperfluorescent area on FA, which corresponded to the clinical location of the polyp (80.0% vs. 16.7%, p<0.001) and blockage of fluorescence on FA (61.7% vs. 16.7%, p=0.001).
We identified several distinguishing features on FA which are highly predictive of PCV compared to AMD. In situations where confirmatory investigations such as ICGA are unavailable or contra-indicated, it is possible to identify patients who are likely to have PCV using FA characteristics. Ophthalmologists who detect such features on FA should have a high index of suspicion for PCV.