Purpose
Polypoidal choroidal vasculopathy (PCV) has high prevalence among Asians, with variable clinical course and visual prognosis, suggesting the existence of clinical subtypes. We describe a novel classification system for PCV based on indocyanine-green (ICG) angiography, and correlate it with clinical outcomes.
Methods
Interventional longitudinal study of 107 consecutive patients with PCV. Images were independently graded by two fellowship-trained, reading center certified retinal specialists. A standardized set of diagnostic criteria was used to confirm the presence of PCV, after which angiographic features were graded and used to classify the patients into subgroups. Visual outcomes were reviewed at specific time intervals during the course of follow up. Risk factors for clinical outcomes were analyzed using multivariate analysis.
Results
Three distinct PCV subtypes were seen: Type A (inter-connecting channels)-25%; Type B (branching vascular network)-26.2%; Type C (active leakage)-48.8%. The ICG subtypes correlated with specific, differentiating pathologic features which were consistently demonstrated on OCT. At all review periods, the highest rate of moderate visual loss occurred in Type C PCV, followed by Types B and A (41.2% vs. 11.1% vs. 0% at 5 years). Good visual outcomes (≥20/40) were highest in Type A, compared to Types B and C (83.3% vs. 62.5% vs. 20%, p=0.034). Independent risk factors for visual outcomes were PCV subtype (odds ratio [OR] 2.84,p=0.025) and age (OR 1.10,p=0.022).
Conclusions
We have established a novel classification system for PCV based on angiography and anatomy. The clinical and visual outcomes are reliably predicted by this classification, demonstrating that PCV consists of distinct, previously unrecognized, clinical subtypes instead of a single disease entity as originally believed. This classification system has potential application in clinical practice and multicenter randomized trials.