Consensus group on PCV develops OCT-based diagnostic criteria, revised nomenclature
The new criteria eliminate the need for ICG angiography, simplify diagnosis and better guide treatment.
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A panel of retina specialists developed and validated a set of diagnostic criteria based on OCT and fundus photography to differentiate polypoidal choroidal vasculopathy from neovascular age-related macular degeneration.
“The current gold standard for diagnosing PCV requires indocyanine green angiography (ICGA), but in many practices, and increasingly so, ICGA is not routinely performed,” Chui Ming Gemmy Cheung, MD, FRCOphth, told Ocular Surgery News. “Having a set of OCT-based criteria will help many clinicians identify the PCV variant and make the right decision about treatment.”
A second task of the group was to revise some of the current PCV-related terminology and propose an updated nomenclature based on the latest imaging and histological findings.
The outcomes of the consensus meetings of this group, which gathered specialists from the Asia-Pacific region, Europe and the United States, were published in Ophthalmology.
Diagnostic criteria
PCV is a subtype of neovascular AMD that accounts for about 50% of neovascular AMD cases in Asia. It is significantly less frequent in other regions, although the current 10% to 20% rate might be an underestimation, in that ICGA is not usually performed routinely. Misdiagnosing PCV might lead to suboptimal treatment outcomes because anti-VEGF injections alone do not work in all cases. As mentioned in the paper by Cheung and co-authors, “in clinical series describing the outcomes of treatment of nAMD, eyes that were observed to be poor responders to anti-VEGF monotherapy subsequently were found to have the PCV variant.” Therefore, “distinguishing PCV from typical nAMD is desirable and clinically important.”
“Several groups have already described features that are commonly seen in PCV and particularly combination of signs, visible on OCT, that may help differentiating PCV from nAMD. In this current group, by reviewing clinical cases we proposed a list of nine features and systematically evaluated the performance of each of them individually and then in combinations. The combination of three OCT-based ‘major criteria,’ namely sub-RPE ring-like lesion, enface OCT complex RPE elevation and sharp-peaked PED, achieved an area under the curve of 0.90,” Cheung said.
This new scheme was further validated in a separate subset of 110 eyes, achieving accuracy of 82%.
A better targeted treatment
In a broad sense, differentiating between neovascular AMD and PCV may not matter a lot initially because most clinicians would start with anti-VEGF monotherapy in both cases, Cheung said.
“However, for those patients who do not show an optimal response after the initial course of injections, we want to step back, pause and rethink the strategy. And that’s a challenge if we don’t have a baseline ICGA. With an OCT-based set of criteria, we are able to go back, reexamine the case and ask ourselves: Could this be PCV? OCT may well be able to answer that question in the majority of cases,” she said.
At that point, treatment could be adjusted using different options, such as switching to another anti-VEGF agent or combining anti-VEGF injections with photodynamic therapy.
“There are still management questions that require further studies, but at least we will be able to address the diagnosis in a more precise manner,” Cheung said.
Consensus nomenclature
PCV is a bicomponent disease, in which the two components are the polypoidal lesion and the branching vascular network. The consensus group discussed some of the alternative terminology found in the literature, such as “polyps” and “aneurysmal lesions,” and reviewed clinical and imaging observations to propose updated nomenclature recommendations.
“First, we agreed that PCV lesions are not a fleshy, solid mass and therefore suggested to avoid the term ‘polyp.’ We also recommended keeping the current term ‘polypoidal lesion’ rather than change it to ‘aneurysm’ or ‘aneurysmal lesion’ because there are still some doubts on whether all these lesions represent aneurysms,” Cheung said.
As for the second component, the group recommended the term “branching neovascular” rather than “vascular” network to better reflect the neovascular nature of the PCV lesion.
“Histology, OCT and more recently OCT angiography are showing us that this network resides in between the Bruch’s membrane and the RPE, which suggests that it is not intrachoroidal but rather located in the same place as an occult type 1 neovascularization,” Cheung said.
The encouraging response to anti-VEGF therapy also confirms that the lesion is similar to a type 1 neovascularization.
“Therefore, we suggested that a better term to highlight the nature of this network is ‘branching neovascular network,’” Cheung said.
Consensus nomenclature and diagnostic criteria were the first output of the group, newly formed under the auspices of the Asia-Pacific Ocular Imaging Society, a subsidiary society of the Asia-Pacific Academy of Ophthalmology.
“APOIS has several workgroups focused on imaging-related work, including retina, cornea and glaucoma, and the PCV workgroup is one of them. We have been very lucky to be able to gather representatives from many different countries within Asia, Australia, Europe and the USA. It has been a prestigious group to work with, and we plan to continue to look at other aspects of PCV to hopefully advance the understanding of this disease and provide practical guidelines for the whole community,” Cheung said.
- For more information:
- Chui Ming Gemmy Cheung, MD, FRCOphth, can be reached at Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Avenue, 10 Singapore 168751, Singapore; email: gemmy.cheung.c.m@singhealth.com.sg.
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