Polypoidal choroidal vasculopathy: an angiographic discussion

Efficacy of Intravitreal Anti-VEGF Agents in Neovascular Age-Related Macular Degeneration Patients with or without Polypoidal Choroidal Vasculopathy: A Meta-Analysis

Aims/Background The classification of polypoidal choroidal vasculopathy (PCV) as a subtype of neovascular age-related macular degeneration (nAMD) remained an ongoing controversy. This meta-analysis examines the efficacy of intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents in nAMD patients with or without PCV. Methods A systematic search was conducted in four databases, including PubMed, EMBASE, MEDLINE, and Cochrane Library, from their inception to 1 July 2023. The outcome measure was the change in best-corrected visual acuity (BCVA) and center retinal thickness (CRT) from the baseline to different follow-up durations. Furthermore, sensitivity analysis was performed when significant heterogeneity was detected. Results This meta-analysis included sixteen studies involving 6679 patients, comprising 5070 non-PCV and 1609 PCV cases. The findings revealed that the improvement in BCVA at 6-month follow-up (mean difference (MD) = 0.05; 95% confidence interval (CI), 0.02 to 0.07; p = 0.0001) and the reduction in CRT at 3-month follow-up duration (MD = 10.29; 95% CI, 0.93 to 19.66; p = 0.03) were significantly greater in the PCV group compared to the non-PCV group. Conclusion This meta-analysis indicates that PCV may exhibit better short-term efficacy in response to anti-VEGF therapy than non-PCV. Systematic Review Registration PROSPERO (CRD42023445591).

Polypoidal Choroidal Vasculopathy: Evaluation Based on 3-Dimensional Reconstruction of OCT Angiography

OBJECTIVE

Three-dimensional (3D) reconstruction using swept-source OCT angiography (SS-OCTA) can provide insights into the nature and structure of polypoidal choroidal vasculopathy (PCV) and its component parts, the polypoidal lesion (PL) and the branching neovascular network (BNN). This study aims to describe novel observations of PCV using 3D reconstruction of SS-OCTA, and to compare these observations with similar images of type I macular neovascularization (MNV) typical neovascular age-related macular degeneration (nAMD).

DESIGN

Clinical case series.

SUBJECTS

Patients with PCV in either eye from clinical studies conducted in a tertiary retina center.

METHODS

Images with prespecified SS-OCTA imaging protocol were obtained and reconstructed in 3D. Forty neovascularization lesions (30 PCV and 10 typical nAMD) based on SS-OCTA were analyzed.

MAIN OUTCOME MEASURES

The following 3 specific features were evaluated: (1) the pattern of flow signal within the PLs as either homogenous or showing internal vascular architecture; (2) the configuration of the BNN as hypermature, mature, or immature; and (3) the spatial arrangement of the PLs in relation to the BNN. Comparisons were made between PCV and typical nAMD.

RESULTS

All PLs exhibited internal vascular architecture in the form of coil-like loops and none exhibited homogenous flow. Small focal nodules were present within this internal vascular architecture in 70% of PLs. Branching neovascular networks exhibited a hypermature/mature configuration (100 vs. 50%, P < 0.01) and were associated with thicker choroid compared with typical nAMD type 1 MNV (238.7 ± 104.3 vs. 155.6 ± 49.2, P = 0.02). The BNN and PL were located at distinct anteroposterior planes in 81% of the eyes.

CONCLUSIONS

We identified proliferating vasculature in both the PL and the BNN. Comparison of the configuration suggests that the BNN represents a more chronic and inactive lesion than the PL.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Randomized controlled trials in central serous chorioretinopathy: A review

Central serous chorioretinopathy (CSCR), a common chorioretinal disease, presents with a myriad of manifestations. Acute CSCR presents with localized neurosensory detachment whereas chronic CSCR may show widespread retinal pigment epithelium (RPE) changes, chronic shallow subretinal fluid, and choroidal neovascularization (CNV) suggestive of a variable natural history leading to suboptimal visual outcomes. Even though multiple treatment options including laser photocoagulation, photodynamic therapy, micropulse laser, anti-vascular endothelial growth factors, and systemic drugs (spironolactone, eplerenone, melatonin, mifepristone) are available, there is an absence of any standardized treatment protocol or gold standard treatment modality. Moreover, their performance compared to observation especially in acute CSCR is still debatable. Compared to other chorioretinal diseases such as age-related macular degeneration, diabetic retinopathy, diabetic macular oedema, and retinal vein occlusion, there is a relative dearth of randomized controlled trials in CSCR. Multiple inconsistencies including reliance on history of disease duration, variable inclusion criteria/disease descriptors/study endpoints, and availability of multiple treatment modalities lead to difficulties in designing RCTs. A consensus-based treatment protocol, therefore, is still elusive. We reviewed the literature and compiled the list of papers published to date, wherein we analyse and compare the inclusion criteria, imaging modalities, study endpoints, study duration, and study results. Correcting these discrepancies and deficiencies will help standardize future study designs, facilitating a next step toward a standardized treatment protocol.

Optical coherence tomography in diagnosing polypoidal choroidal vasculopathy. Looking into the future: a systematic review and meta-analysis

Background

Polypoidal choroidal vasculopathy (PCV) is an exudative maculopathy with features similar to wet age macular degeneration. The incidence of PCV is known to be higher in the Asian population compared to Caucasians. Imaging modality is needed to make the diagnosis of PCV. Although Indocyanine green angiography (ICGA) is still the gold standard, it is not routinely performed in vitreoretinal practice. Thus another imaging modality is currently a popular research area. Spectral domain optical coherence tomography (SD-OCT) has emerged as a new imaging modality mostly available in clinics. Some studies have reported the sensitivity and specificity of SD-OCT in diagnosing PCV with different results and thresholds.

Methods

Relevant studies from PubMed, Science Direct and Google Scholar databases were systematically searched. In random effect models using STATA 14 software, a meta-analysis was performed to determine the pooled diagnostic accuracy. QUADAS 2 was used to evaluate the risk of bias of each study by Revman 5.4 software.

Results

Seven eligible studies which met the inclusion and exclusion criteria were enrolled in this study. A total of 911 eyes were included to investigate the diagnostic accuracy of SD-OCT. As a result, the pooled sensitivity was 0.91 (95% CI 0.87–0.93), specificity 0.88 (95% 0.83–0.92), positive likelihood ratio 8, negative likelihood ratio 11, the area under the summary receiver operating characteristic curve 0.95 (95% CI 0.93–0.97), and diagnostic odds ratio 71.81 (95% CI 38.89–132.74).

Conclusion

SD-OCT provided a high diagnostic value for detecting PCV. Sharply peaked pigment epithelial detachment (PED), notched PED, bubble sign, multiple PED, and double-layer sign were the most common features found in PCV.

Hyaluronidase-1-mediated glycocalyx impairment underlies endothelial abnormalities in polypoidal choroidal vasculopathy

Background

Polypoidal choroidal vasculopathy (PCV), a subtype of age-related macular degeneration (AMD), is a global leading cause of vision loss in older populations. Distinct from typical AMD, PCV is characterized by polyp-like dilatation of blood vessels and turbulent blood flow in the choroid of the eye. Gold standard anti-vascular endothelial growth factor (anti-VEGF) therapy often fails to regress polypoidal lesions in patients. Current animal models have also been hampered by their inability to recapitulate such vascular lesions. These underscore the need to identify VEGF-independent pathways in PCV pathogenesis.

Results

We cultivated blood outgrowth endothelial cells (BOECs) from PCV patients and normal controls to serve as our experimental disease models. When BOECs were exposed to heterogeneous flow, single-cell transcriptomic analysis revealed that PCV BOECs preferentially adopted migratory-angiogenic cell state, while normal BOECs undertook proinflammatory cell state. PCV BOECs also had a repressed protective response to flow stress by demonstrating lower mitochondrial functions. We uncovered that elevated hyaluronidase-1 in PCV BOECs led to increased degradation of hyaluronan, a major component of glycocalyx that interfaces between flow stress and vascular endothelium. Notably, knockdown of hyaluronidase-1 in PCV BOEC improved mechanosensitivity, as demonstrated by a significant 1.5-fold upregulation of Krüppel-like factor 2 (KLF2) expression, a flow-responsive transcription factor. Activation of KLF2 might in turn modulate PCV BOEC migration. Barrier permeability due to glycocalyx impairment in PCV BOECs was also reversed by hyaluronidase-1 knockdown. Correspondingly, hyaluronidase-1 was detected in PCV patient vitreous humor and plasma samples.

Conclusions

Hyaluronidase-1 inhibition could be a potential therapeutic modality in preserving glycocalyx integrity and endothelial stability in ocular diseases with vascular origin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-022-01244-z.

Pachychoroid spectrum disease

Recent improvements in ophthalmic imaging have led to the identification of a thickened choroid or pachychoroid to be associated with a number of retinal diseases. The number of conditions linked to this phenotype has continued to widen with specific endophenotypes found within the pachychoroid spectrum. The spectrum includes choroidal features such as focal or diffuse choroidal thickening and thinning of the overlying inner choroid, and choroidal hyperpermeability as demonstrated by indocyanine green angiography. In addition, these diseases are associated with overlying retinal pigmentary changes and retinal pigment epithelial dysfunction and may also be associated with choroidal neovascularization. This article provides a comprehensive review of the literature looking at diseases currently described within the pachychoroid spectrum including central serous chorioretinopathy, pachychoroid pigment epitheliopathy, pachychoroid neovasculopathy, polypoidal choroidal vasculopathy/aneurysmal type 1 neovascularization, peripapillary pachychoroid disease and focal choroidal excavation. We particularly focus on clinical imaging, genetics and pathological findings in these conditions with the aim of updating evidence suggesting a common aetiology between diseases within the pachychoroid spectrum.

Choroidal Vascular Abnormalities by Ultra-widefield Indocyanine Green Angiography in Polypoidal Choroidal Vasculopathy

Purpose

To evaluate vortex vein engorgement and choroidal vascular hyperpermeability in patients with polypoidal choroidal vasculopathy (PCV) using ultra-widefield indocyanine green angiography (ICGA).

Methods

This retrospective case control study included 51 patients with unilateral PCV, 7 patients with bilateral PCV, and 43 age-matched controls. The number of quadrants of vortex vein engorgement was evaluated in the middle phase of ICGA, which was classified as extended engorgement if the dilated choroidal vessels expanded to the macula. The area of choroidal vascular hyperpermeability was quantified stereographically from the late-phase ICGA and correlated with clinical and optical coherence tomography findings.

Results

Affected eyes had a larger choroidal hyperpermeability area and a thicker subfoveal choroid than eyes in the control group or fellow eyes (P < 0.001, P < 0.001). More quadrants with extended vortex vein engorgement were observed in affected eyes than in fellow eyes (P < 0.001). Significant differences were observed in the area of choroidal hyperpermeability, Haller layer thickness and greatest linear dimension according to the extended vortex vein engorgement in eyes with PCV (P < 0.001, P = 0.001, and P = 0.001, respectively). The area of choroidal hyperpermeability was significantly correlated with subfoveal choroidal thickness (P < 0.001, Pearson's correlation coefficient = 0.471).

Conclusions

Ultra-widefield ICGA results revealed that patients with PCV had vortex vein engorgement and an increased choroidal hyperpermeability area. The results from this study provide substantial information to clarify the pathogenesis and predict the prognosis in the patients with PCV.

Comparison of Polypoidal Choroidal Vasculopathy Lesion Sizes Measured on Multicolor Imaging and Indocyanine Green Angiography

Purpose

To evaluate the areas of lesion components of polypoidal choroidal vasculopathy (PCV) measured using multicolor imaging compared to indocyanine green angiography (ICGA).

Methods

In a prospective study of 50 consecutive treatment-naïve PCV patients, multicolor imaging and ICGA were performed. The images were independently graded by reading center-certified retinal specialists to confirm the diagnosis of PCV and identify lesion components. The areas of the respective lesion components were compared.

Results

The mean age of the participants was 67.8 years. PCV was diagnosed in 96% of eyes using multicolor imaging. The mean numbers of polypoidal lesions identified using ICGA and multicolor were 4.0 and 2.1, respectively (P < 0.001), with mean total polypoidal lesion areas of 0.32 mm² versus 0.30 mm² (P = 0.727). The area of the branching vascular network (BVN) on ICGA was 7.8 mm² compared to 5.7 mm² on multicolor imaging (P = 0.289). Patients with four or more polypoidal lesions on ICGA had larger differences in total lesion area between ICGA and multicolor imaging (4.07 vs. –0.70 mm², p = 0.039). Those with total lesion area ≥ 2.0 mm² on ICGA had larger differences in mean polypoidal lesion number compared to those with smaller areas (2.2 vs. 0.5; P = 0.026).

Conclusions

Multicolor imaging is a useful, noninvasive adjunct for detecting PCV lesion components, revealing lesion areas similar to but generally smaller than those seen on ICGA. This is important to consider when making treatment decisions with different imaging modalities

Translational Relevance

New features seen on multicolor imaging can aid in the diagnosis and treatment of PCV.

The Role of Imaging in Planning Treatment for Central Serous Chorioretinopathy

Central serous chorioretinopathy (CSC) is a controversial disease both in terms of clinical classification and choice of therapeutic strategy. Choroidal layers, retinal pigment epithelium (RPE), photoreceptors, and retina are involved to varying degrees. Beyond well-known symptoms raising the clinical suspect of CSC and slit-lamp fundus examination, multimodal imaging plays a key role in assessing the extent of chorioretinal structural involvement. Subretinal fluid (SRF) originating from the choroid leaks through one or multiple RPE defects and spreads into the subretinal space. Spontaneous fluid reabsorption is quite common, but in some eyes, resolution can be obtained only after treatment. Multiple therapeutic strategies are available, and extensive research identified the most effective procedures. Imaging has carved a significant role in guiding the choice of the most appropriate strategy for each single CSC eye. Multiple biomarkers have been identified, and all of them represent a diagnostic and prognostic reference point. This review aims to provide an updated and comprehensive analysis of the current scientific knowledge about the role of imaging in planning the treatment in eyes affected by CSC.

Comparison of machine learning tools for the prediction of AMD based on genetic, age, and diabetes-related variables in the Chinese population

Introduction

Age-related macular degeneration (AMD) is the main cause of visual impairment and the most important cause of blindness in older people. However, there is currently no effective treatment for this disease, so it is necessary to establish a risk model to predict AMD development.

Methods

This study included a total of 202 subjects, comprising 82 AMD patients and 120 control subjects. Sixty-six single-nucleotide polymorphisms (SNPs) were identified using the MassArray assay. Considering 14 independent clinical variables as well as SNPs, four predictive models were established in the training set and evaluated by the confusion matrix, area under the receiver operating characteristic (ROC) curve (AUROC). The difference distributions of the 14 independent clinical features between the AMD and control groups were tested using the chi-squared test. Age and diabetes were adjusted using logistic regression analysis and the “genomic-control” method was used for multiple testing correction.

Results

Three SNPs (rs10490924, OR = 1.686, genomic-control corrected p-value (GC) = 0.030; rs2338104, OR = 1.794, GC = 0.025 and rs1864163, OR = 2.125, GC = 0.038) were significant risk factors for AMD development. In the training set, four models obtained AUROC values above 0.72.

Conclusions

We believe machine learning tools will be useful for the early prediction of AMD and for the development of relevant intervention strategies.

The comparison of spectral domain optical coherence tomography and indocyanine green angiography in the diagnosis of polypoidal choroidal vasculopathy

OBJECTIVES

To evaluate the diagnostic capability of spectral domain optical coherence tomography (SD-OCT) in patients with potential diagnostic findings for polypoidal choroidal vasculopathy (PCV).

MATERIALS AND METHODS

Ninety-three eyes with potential diagnostic findings for PCV were prospectively evaluated. Patients with multiple retinal pigment epithelial detachment (RPED), sharp RPED peak, RPED notch, hyporeflective lumen representing polyps, double-layer sign and the presence of hyperreflective intraretinal hard exudate were considered as PCV in SD-OCT. The sensitivity and specificity of SD-OCT in the diagnosis of PCV were determined by comparing SD-OCT-based diagnosis with indocyanine green angiography (ICGA).

RESULTS

Sixty-nine (74.2%) of 93 eyes included in the study were confirmed with ICGA and diagnosed as PCV. The sensitivity and specificity of SD-OCT for the diagnosis of PCV were 75.3% and 75%, respectively.

CONCLUSION

The SD-OCT-based method helps clinicians to develop appropriate diagnostic and treatment strategies for patients in whom ICGA cannot be used.

Early changes of vascular lesions and responses to combined photodynamic therapy in patients with polypoidal choroidal vasculopathy

PURPOSE

To evaluate early changes of vascular lesions and their associations with the early responses to combined photodynamic therapy (PDT) in eyes with polypoidal choroidal vasculopathy (PCV).

METHODS

This study evaluated 19 eyes of 19 patients with PCV who underwent PDT combined with anti-vascular endothelial growth factor injections and were followed for 3 months. All subjects were examined 1 week and 1, 2, and 3 months after combined PDT. "Active" cases were defined as recurrence or persistence of serous retinal detachment or subretinal hemorrhage detected within 3 months. Branching vascular networks (BVNs) were evaluated by optical coherence tomography angiography (OCTA) and polyps by indocyanine-green angiography.

RESULTS

In total, 16%, 58%, 84%, and 89% of eyes displayed BVNs 1 week, 1, 2, and 3 months after PDT, respectively. BVNs were detected significantly more often 1 month after PDT in the "active" group than "inactive" group (89% vs. 30%, p = 0.020). There were significantly higher overall proportions of BVNs detected by OCTA in the "active" group than "inactive" group (p = 0.0058).

CONCLUSION

In most cases, BVNs disappeared once and gradually appeared again within 3 months. Detecting BVNs using OCTA from early phases could be a helpful biomarker to assess the early responses to PDT in eyes with PCV.

Polypoidal choroidal vasculopathy: a comprehensive clinical update

Polypoidal choroidal vasculopathy as a disease is yet to be comprehended completely. The clinical features consisting of huge serosanguineous retinal pigment epithelial and neurosensory layer detachments, although unique may closely mimick neovascular age-related macular degeneration and other counterparts. The investigative modalities starting from indocyanine angiography to optical coherence tomography angiography provide diagnostic challenges. The management strategies based on the available therapies are plenty and not vivid. A detailed review with clarifying images has been compiled with an aim to help the readers in getting a better understanding of the disease.

Proteolytic Degradation and Inflammation Play Critical Roles in Polypoidal Choroidal Vasculopathy

Polypoidal choroidal vasculopathy (PCV) is a common subtype of wet age-related macular degeneration in Asian populations, whereas choroidal neovascularization is the typical subtype in Western populations. The cause of PCV is unknown. By comparing the phenotype of a PCV mouse model expressing protease high temperature requirement factor A1 (HTRA1) in retinal pigment epithelium with transgenic mice expressing the inactive HTRA1S328A, we showed that HTRA1-mediated degradation of elastin in choroidal vessels is critical for the development of PCV, which exhibited destructive extracellular matrix remodeling and vascular smooth muscle cell loss. Compared with weak PCV, severe PCV exhibited prominent immune complex deposition, complement activation, and infiltration of inflammatory cells, suggesting inflammation plays a key role in PCV progression. More important, we validated these findings in human PCV specimens. Intravitreal delivery of an HTRA1 inhibitor (DPMFKLboroV) was effective (36% lesion reduction; P = 0.009) in preventing PCV initiation but ineffective in treating existing lesions. Anti-inflammatory glucocorticoid was effective in preventing PCV progression but ineffective in preventing PCV initiation. These results suggest that PCV pathogenesis occurs through two stages. The initiation stage is mediated by proteolytic degradation of extracellular matrix proteins attributable to increased HTRA1 activity, whereas the progression stage is driven by inflammatory cascades. This study provides a basis for understanding the differences between PCV and choroidal neovascularization, and helps guide the design of effective therapies for PCV.

Efficacy and Safety of Ranibizumab With or Without Verteporfin Photodynamic Therapy for Polypoidal Choroidal Vasculopathy: A Randomized Clinical Trial

Importance

Polypoidal choroidal vasculopathy (PCV) is a common subtype of exudative age-related macular degeneration among Asian individuals. To our knowledge, there are no large randomized clinical trials to evaluate intravitreal ranibizumab, with and without verteporfin photodynamic therapy (vPDT), for the treatment of PCV.

Objective

To compare the efficacy and safety of combination therapy of ranibizumab and vPDT with ranibizumab monotherapy in PCV.

Design, Setting, and Participants

A double-masked, multicenter randomized clinical trial of 322 Asian participants with symptomatic macular PCV confirmed by the Central Reading Center using indocyanine green angiography was conducted between August 7, 2013, and March 2, 2017.

Interventions

Participants were randomized 1:1 to ranibizumab, 0.5 mg, and vPDT (n = 168; combination therapy group) or ranibizumab, 0.5 mg, and sham PDT (n = 154; monotherapy group). All participants received 3 consecutive monthly ranibizumab injections, followed by a pro re nata regimen. Participants also received vPDT/sham PDT on day 1, followed by a pro re nata regimen based on the presence of active polypoidal lesions.

Main Outcomes and Measures

Step 1 assessed whether combination therapy was noninferior (5-letter margin) to monotherapy for change in best-corrected visual acuity from baseline and superior in complete polyp regression. If noninferiority was established, step 2 assessed whether combination therapy was superior to monotherapy measured by best-corrected visual acuity change at month 12.

Results

Baseline demographics of the 322 participants were comparable between the treatment groups. Mean (SD) age of the patients was 68.1 (8.8) years, and overall, 69.9% of the patients were men. At baseline, the overall mean best-corrected visual acuity and mean central subfield thickness were 61.1 letters and 413.3 μm, respectively. At 12 months, mean improvement from baseline was 8.3 letters with combination therapy vs 5.1 letters with monotherapy (mean difference, 3.2 letters; 95% CI, 0.4-6.1), indicating that combination therapy met the predefined criterion for noninferiority as well as being superior to monotherapy (P = .01). Combination therapy was also superior to monotherapy in achieving complete polyp regression at month 12 (69.3% vs 34.7%; P < .001). Over 12 months, the combination therapy group received a median of 4.0 ranibizumab injections compared with 7.0 in the monotherapy group. Vitreous hemorrhage was the only ocular serious adverse event (combination therapy group, 1 [0.6%]; monotherapy group, 3 [2.0%]).

Conclusions and Relevance

After 12 months, combination therapy of ranibizumab plus vPDT was not only noninferior but also superior to ranibizumab monotherapy in best-corrected visual acuity and superior in complete polyp regression while requiring fewer injections. Combination therapy should be considered for eyes with PCV.

Trial Registration

clinicaltrials.gov Identifier: NCT01846273.

Pathologic study of early manifestations of polypoidal choroidal vasculopathy and pathogenesis of choroidal neo-vascularization

Purpose

To describe the histopathologic features of an early case of presumably bilateral polypoidal choroidal vasculopathy (PCV) in two eyes obtained at autopsy from a patient with no prior ocular therapy.

Observations

The choroid of both eyes at the macular and peripapillary regions was greatly thickened with dilated, thin walled choroidal venules intertwining with arteriosclerotic arterioles in the Sattler's layer of the choroidal vasculature. At the temporal and nasal equatorial regions of both eyes many of these congested venular channels abruptly disappeared and were replaced by loose connective tissue with loss of the normal choroidal stromal tissue and uveal melanocytes. A few remaining venules showed intraluminal sloughing of endothelial cells and deposition of fibrinous material networks suggesting occlusion of these choroidal venules. At this equatorial location, serous detachment of retinal pigment epithelium (RPE) appeared and a thin neovascular membrane with cords of endothelial cell invaded into the sub-RPE space. Anteriorly, the neovascular membrane expanded and bulged into the sub-retinal space with dilated neovascular capillaries in a “grape like” or polypoidal configuration.

Conclusion and importance

Polypoidal Choroidal Vasculopathy is a disease of the dilated and multi-layered choroidal venules. Occlusion of these choroidal vascular channels might give rise to choroidal stasis and ischemia leading to serous RPE detachment and a sub-RPE neovascular membrane. Gross dilatation of the choroidal venules and capillaries in the sub-RPE neovascular membrane leads to the characteristic “grape like” structures, a unique clinical feature in this disease entity. These pathologic features of PCV are different from the pathologic changes of neovascular age-related macular degeneration (nAMD). Consequently, PCV and nAMD are two distinct diseases. However, in the late stage of both entities, choroidal ischemia in both diseases, lead to sub-RPE neovascularization and subsequent sub-RPE and/or sub-retinal hemorrhage. These results in both entities showed comparable clinical and pathologic features that are frequently mistaken PCV as a sub-type of Neovascular AMD.

Shared genetic variants for polypoidal choroidal vasculopathy and typical neovascular age-related macular degeneration in East Asians

Polypoidal choroidal vasculopathy (PCV), a subtype of age-related macular degeneration (AMD) more frequently seen in East Asians, has both common and distinct clinical manifestations with typical neovascular AMD (tAMD). We aim to examine the extent to which common genetic variants are shared between these two subtypes. We performed the meta-analysis of association in a total of 1062 PCV patients, 1157 tAMD patients and 5275 controls of East Asian descent from the Genetics of AMD in Asians Consortium at the 34 known AMD loci. A total of eight loci were significantly associated with PCV, including age-related maculopathy susceptibility 2 (ARMS2)-HtrA serine peptidase 1 (HTRA1), complement factor H (CFH), C2-CFB-SKIV2L, CETP, VEGFA, ADAMTS9-AS2 and TGFBR1 (P<5 × 10^-4) from the single-nucleotide polymorphism-based test and COL4A3 from the gene-based tests (P_gene=2.02 × 10^-4). PCV and tAMD are genetically highly correlated (r_g=0.69, P=4.68 × 10^-3), with AMD known loci accounting for up to 36% variation. Weaker association for PCV was observed at ARMS2-HTRA1 (P_dif=4.39 × 10^-4) and KMT2E-SRPK2(P_dif=4.43 × 10^-3), compared with tAMD. Variants at CFH, CETP and VEGFA exhibited different association signals in East Asians, in contrast to those in European individuals. Our data suggest a substantially shared genetic susceptibility for PCV and tAMD, while also highlight the unique associations for PCV, which is useful in understanding the pathogenesis of PCV.

Intravitreal Aflibercept for Neovascular Polypoidal Choroidal Vasculopathy in a Predominantly Non-Asian Population: RIVAL Results

BACKGROUND AND OBJECTIVE

To evaluate safety and efficacy of intravitreal aflibercept (Eylea; Regeneron, Tarrytown, NY) injection (IAI) for the treatment of neovascular polypoidal choroidal vasculopathy (PCV) in a predominantly non-Asian population.

PATIENTS AND METHODS

This was an open-label, prospective, unmasked, nonrandomized clinical trial. Twenty eyes with neovascular PCV received monthly 2.0 mg IAI for 3 months followed by mandatory IAI every 2 months for 12 months.

RESULTS

The mean change in ETDRS best-corrected visual acuity from baseline to 1 year was +11 letters in the treatment-naïve group, +5 letters in the treatment non-naïve group, and +9 letters overall. There was an overall mean reduction of 70 µm from baseline central subfield thickness (CST) at 1 year. Patients received a mean of 6.2 mandatory and 0.7 additional IAI injections overall during the course of 1 year. No serious ocular adverse events were reported.

CONCLUSION

At 1 year, neovascular PCV in a predominantly non-Asian population treated with IAI demonstrated favorable visual, anatomic, and safety outcomes. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:34-44.].

ANGIOGRAPHIC FINDINGS OF RANIBIZUMAB-RESISTANT POLYPOIDAL CHOROIDAL VASCULOPATHY AFTER SWITCHING TO A TREAT-AND-EXTEND REGIMEN WITH INTRAVITREAL AFLIBERCEPT

PURPOSE

The aim of this study was to study the angiopathic findings of ranibizumab-resistant polypoidal choroidal vasculopathy after switching to a treat-and-extend regimen with intravitreal aflibercept.

METHODS

The authors retrospectively reviewed 17 eyes of 17 Japanese patients with polypoidal choroidal vasculopathy (10 men and 7 women, age: 73.8 ± 7.4 years) who were treated with intravitreal aflibercept (2 mg/0.05 mL) injections from February 2013 to August 2014 at Tokyo University Hospital. All patients had switched to aflibercept because their polypoidal choroidal vasculopathy had been refractory to ranibizumab.

RESULTS

The mean logMAR best-corrected visual acuity at baseline and after 12 months of therapy was 0.30 ± 0.29 (Snellen equivalent: 20/40) and 0.17 ± 0.26 (20/30) (paired t-test P < 0.001). Visual acuity remained stable in 5 cases (29%), deteriorated in 3 (18%), and improved in 9 (53%). Branching vascular networks persisted in all 17 eyes but shrank in 15 (88%). The mean lesion diameter was 3329 ± 1261 μm at baseline and 3180 ± 1247 μm after 12 months (P = 0.0002).

CONCLUSION

A treat-and-extend regimen with intravitreal aflibercept for ranibizumab-resistant patients resulted in branching vascular network shrinkage over a 1-year period.

PATTERNS OF FUNDUS AUTOFLUORESCENCE DEFECTS IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION SUBTYPES

PURPOSE

To test define characteristic fundus autofluorescence patterns of different exudative age-related macular degeneration subtypes.

METHODS

Cross-sectional study. Fifty-two patients with choroidal neovascularization because of three different neovascular age-related macular degeneration subtypes were included in the study. Macular and peripheral fundus autofluorescence patterns of study subjects were compared in a masked fashion.

RESULTS

Fundus autofluorescence patterns of all three neovascular age-related macular degeneration subtypes revealed similar patterns. However, peripapillary hypo-autofluorescence was more common among patients with polypoidal choroidal vasculopathy (88.2%) compared with patients with retinal angiomatous proliferation (12.5%) and patients without retinal angiomatous proliferation and polypoidal choroidal vasculopathy (21.1%) (P < 0.0001).

CONCLUSION

Presence of peripapillary fundus autofluorescence defects in neovascular age-related macular degeneration maybe suggestive of polypoidal choroidal vasculopathy as a variant of neovascular age-related macular degeneration.

Accurate Joint-Alignment of Indocyanine Green and Fluorescein Angiograph Sequences for Treatment of Subretinal Lesions

In ophthalmology, aligning images in indocyanine green and fluorescein angiograph sequences is important for the treatment of subretinal lesions. This paper introduces an algorithm that is tailored to align jointly in a common reference space all the images in an angiogram sequence containing both modalities. To overcome the issues of low image contrast and low signal-to-noise ratio for late-phase images, the structural similarity between two images is enhanced using Gabor wavelet transform. Image pairs are pairwise registered and the transformations are simultaneously and globally adjusted for a mutually consistent joint alignment. The joint registration process is incremental and the success depends on the correctness of matches from the pairwise registration. To safeguard the joint process, our system performs the consistency test to exclude incorrect pairwise results automatically to ensure correct matches as more images are jointly aligned. Our dataset consists of 60 sequences of polypoidal choroidal vasculopathy collected by the EVEREST Study Group. On average, each sequence contains 20 images. Our algorithm successfully pairwise registered 95.04% of all image pairs, and joint registered 98.7% of all images, with an average alignment error of 1.58 pixels.

Comparison of indocyanine green angiography and optical coherence tomographic angiography in polypoidal choroidal vasculopathy

PurposeTo compare optical coherence tomographic angiography (OCTA) and indocyanine green angiography (ICGA) images for detecting polypoidal lesions (PLs) and branching vascular networks (BVNs), and to measure the polypoidal areas (PAs) in patients with polypoidal choroidal vasculopathy (PCV).MethodsAll patients underwent ICGA, optical coherence tomography (OCT), and OCTA. We compared the detection sensitivity for PL and BVN, as evaluated by the ICGA and OCTA images. Furthermore, PA measured by ICGA was divided into two groups: one in which the area could be measured by OCTA (ICGA+OCTA+) and the other in which the area could not be measured by OCTA (ICGA+OCTA-).ResultsTwenty-one consecutive eyes of 21 patients (mean age, 73.8±9.8 years) were included. ICGA detected PL in all eyes (100%), whereas OCTA detected PL in 16 eyes (75.2%); ICGA detected BVN in 15 eyes (71.4%), whereas OCTA detected BVN in 20 eyes (95.2%). The mean PA in ICGA+OCTA+ and ICGA+OCTA- was 0.24±0.04 and 0.14±0.01 mm2, respectively; a significant difference was observed between ICGA+OCTA+ PA and ICGA+OCTA- PA (P<0.0001). In addition, the mean PA in the ICGA+OCTA+ group measured by ICGA and OCTA was 0.24±0.04 was 0.19±0.04 mm2, respectively; these values were significantly different (P=0.0046).ConclusionsOCTA might detect more BVNs and fewer PLs compared with ICGA, and PL detected by OCTA might be smaller than those detected by ICGA.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF POLYPOIDAL CHOROIDAL VASCULOPATHY AND POLYPOIDAL CHOROIDAL NEOVASCULARIZATION

PURPOSE

To describe the use of optical coherence tomography angiography (OCT-A) for evaluating the spectrum of polypoidal vascular diseases.

METHODS

Retrospective observational case series of seven patients with polypoidal choroidal vasculopathy (three cases) or polypoidal choroidal neovascularization (four cases). Optical coherence tomography angiography information was acquired using two different OCT-A devices (the Optovue RTVue XR Avanti SD-OCT and the Spectralis OCT angiography). Flow signals within branching vascular networks, type 1 neovascularization and polyps were evaluated. Comparisons were made between en face and cross-sectional OCT-A images. Vascular information from OCT-A was also compared with indocyanine green angiography.

RESULTS

En face images from OCT-A provided anatomical information about branching vascular networks that were comparable to indocyanine green angiography. Polyps were poorly resolved on en face OCT-A images but were clearly defined on cross-sectional OCT-A images. Cross-sectional OCT-A revealed flow signals within focal regions of the polyps with a significant portion of the polyp lumen being devoid of flow signal. Flow signals from cross-sectional OCT-A images also showed that branching vascular networks, type 1 neovascularization, and polyps were confined to the anatomic compartment between the retinal pigment epithelium and Bruch's membrane. It was not possible to detect leakage on en face or cross-sectional OCT-A.

CONCLUSION

The combination of en face and cross-sectional OCT-A images provides anatomical information about polypoidal structures that is comparable to indocyanine green angiography. OCT-A may be a useful modality for the management of polypoidal diseases. However, the limitations of OCT-A identified in this study suggest that it is not a replacement for indocyanine green angiography.

EVEREST study report 3: diagnostic challenges of polypoidal choroidal vasculopathy. Lessons learnt from screening failures in the EVEREST study

Purpose

To describe screening failures in the EVEREST study by examining the imaging characteristics that enabled differentiation of polypoidal choroidal vasculopathy (PCV) from cases that were subsequently diagnosed not to be PCV.

Methods

Post-hoc analysis of 34 patients with PCV reported as screening failures from EVEREST study. Standardised confocal scanning laser indocyanine green angiography (ICGA) images were graded by the Central Reading Centre to confirm PCV diagnosis based on the presence of early focal sub-retinal hyperfluorescence on ICGA and at least one of the following six diagnostic criteria: (1) nodular appearance of polyp(s) on stereoscopic examination, (2) hypofluorescent halo around nodule(s), (3) presence of a branching vascular network, (4) pulsation of polyp(s) on dynamic ICGA, (5) orange sub-retinal nodules on colour fundus photography, or (6) massive sub-macular haemorrhage (≥4 disc areas in size). Additional detailed image grading was performed with stereo-imaging and dynamic early-phase ICGA.

Results

Of the 95 screened PCV cases, 34 were excluded: (1) cases not suitable for recruitment as per the study protocol (n = 14), (2) equivocal lesions on ICGA characterised by small hyperfluorescent dots (n = 9), and (3) cases that were definitely not PCV (non-PCV, n = 11), identified by definitive diagnoses which included one case each of micro-aneurysm, retinal angiomatous proliferation, retino-choroidal anastomosis, small type-2 choroidal neovascularisation, retinal pigment epithelial (RPE) window defect and disciform scar; two cases of lesions where the choroidal vessel changed its course; and three cases of late-onset RPE staining.

Conclusions

Standardised image grading techniques used in EVEREST study enabled effective differentiation of non-PCV from actual PCV.

Electronic supplementary material

The online version of this article (doi:10.1007/s00417-016-3333-y) contains supplementary material, which is available to authorized users.

A missense variant in FGD6 confers increased risk of polypoidal choroidal vasculopathy

Polypoidal choroidal vasculopathy (PCV), a subtype of 'wet' age-related macular degeneration (AMD), constitutes up to 55% of cases of wet AMD in Asian patients. In contrast to the choroidal neovascularization (CNV) subtype, the genetic risk factors for PCV are relatively unknown. Exome sequencing analysis of a Han Chinese cohort followed by replication in four independent cohorts identified a rare c.986A>G (p.Lys329Arg) variant in the FGD6 gene as significantly associated with PCV (P = 2.19 × 10(-16), odds ratio (OR) = 2.12) but not with CNV (P = 0.26, OR = 1.13). The intracellular localization of FGD6-Arg329 is distinct from that of FGD6-Lys329. In vitro, FGD6 could regulate proangiogenic activity, and oxidized phospholipids increased expression of FGD6. FGD6-Arg329 promoted more abnormal vessel development in the mouse retina than FGD6-Lys329. Collectively, our data suggest that oxidized phospholipids and FGD6-Arg329 might act synergistically to increase susceptibility to PCV.

Comparability of retinal thickness measurements using different scanning protocols on spectral-domain optical coherence tomography

Retinal thickness measurements obtained using optical coherence tomography (OCT) play an essential role both in multi-center clinical trials and in normal clinical practice. Different scanning protocols are available on most OCT devices, and it is important to ascertain whether the retinal thickness measurements obtained from these are comparable. This study aimed to compare retinal thickness measurements between raster and radial scanning protocols using spectral-domain OCT (SD-OCT). In a prospective study, 32 healthy subjects were scanned sequentially using raster and radial protocols from a SD-OCT device. For both the raster and radial OCT scans, retinal thicknesses were measured manually subfoveally and at 12 other points at 0.5 mm intervals temporally and nasally on the horizontal OCT B-scan passing through the fovea. The retinal thickness measurements were compared using intraclass correlation (ICC) and Bland-Altman plots. Subfoveal retinal thickness was 227.0 µm when measured on the raster scan and 229.2 µm on the radial scan, with a mean difference of 2.2 µm (P = 0.141).The ICC for agreement was 0.889 (95 % confidence interval 0.818-0.933). Similar results were observed for retinal thickness measurements at all other points, with mean differences ranging from -3.37 to 2.59 µm, and ICC values ranging from 0.837 to 0.972. The retinal thickness measurements obtained by the raster and radial scans of the same SD-OCT device are comparable, with differences of less than 4 µm. This is of relevance when measurements made using different OCT scan protocols are compared.

Individualized ranibizumab therapy strategies in year 3 after as-needed treatment for polypoidal choroidal vasculopathy

BACKGROUND

To investigate the third-year results of ranibizumab monotherapy for polypoidal choroidal vasculopathy (PCV) in individualized treatment regimens based on the outcomes during 2 years.

METHODS

One hundred seventy-two consecutive eyes of 163 prospective treatment-naïve patients with PCV were treated with three monthly intravitreal ranibizumab injections followed by as-needed reinjections and completed a 2-year follow-up. Treatment regimens during the third year were selected individually based on their outcomes from the following treatment regimens: as-needed injections based on quarterly examinations, as-needed injections based on monthly examinations, a monthly ranibizumab injection schedule, and the treat-and-extend schedule. Visual acuity (VA) and foveal thickness at the end of the third year and the prevalence of discontinuous follow-up examinations during the third year were evaluated.

RESULTS

Of 163 patients, 35 (21%) patients were excluded; nine patients had discontinuous follow-up examinations during the third year. In 128 eyes of 128 patients studied during the third year, the significant improvements in VA and foveal thickness 2 years after the first injection compared to baseline were maintained at the end of the third year. Six (18%, 6/34) patients treated with as-needed injections based on quarterly examinations had discontinuous follow-up examinations, the prevalence of which differed significantly (P = 0.025) from the other groups.

CONCLUSIONS

The individualized treatment strategies in the third year based on each patient's outcomes during 2 years maintained the improved VA and avoided discontinuation of follow-up during the third year.

Automatic Segmentation of Polypoidal Choroidal Vasculopathy from Indocyanine Green Angiography Using Spatial and Temporal Patterns

PURPOSE

To develop a computer-aided diagnostic tool for automated detection and quantification of polypoidal regions in indocyanine green angiography (ICGA) images.

METHODS

The ICGA sequences of 59 polypoidal choroidal vasculopathy (PCV) treatment-naïve patients from five Asian countries (Hong Kong, Singapore, South Korea, Taiwan, and Thailand) were provided by the EVEREST study. The ground truth was provided by the reading center for the presence of polypoidal regions. The proposed detection algorithm used both temporal and spatial features to characterize the severity of polypoidal lesions in ICGA sequences. Leave-one-out cross validation was carried out so that each patient was used once as the validation sample. For each patient, a fixed detection threshold of 0.5 on the severity was applied to obtain sensitivity, specificity, and balanced accuracy with respect to the ground truth.

RESULTS

Our system achieved an average accuracy of 0.9126 (sensitivity = 0.9125, specificity = 0.9127) for detection of polyps in the 59 ICGA sequences. Among the total of 222 features extracted from ICGA sequence, the spatial variances exhibited best discriminative power in distinguishing between polyp and nonpolyp regions. The results also indicated the importance of combining spatial and temporal features to further improve detection accuracy.

CONCLUSIONS

The developed software provided a means of detecting and quantifying polypoidal regions in ICGA images for the first time.

TRANSLATIONAL RELEVANCE

This preliminary study demonstrated a computer-aided diagnostic tool, which enables objective evaluation of PCV and its progression. Ophthalmologists can easily visualize the polypoidal regions and obtain quantitative information about polyps by using the proposed system.

The association of elastin gene variants with two angiographic subtypes of polypoidal choroidal vasculopathy

Objective

To compare the association of elastin (ELN) gene variants between two different angiographic phenotypes of polypoidal choroidal vasculopathy (PCV).

Methods

We included 411 treatment-naïve PCV patients and 350 controls in the present study. PCV was classified into two phenotypes (152 Type 1 and 259 Type 2) according to the presence or absence of feeding vessels found in indocyanine-green angiography. Single nucleotide polymorphisms (SNPs) in the ELN region including rs868005, rs884843, rs2301995, rs13239907 and rs2856728 were genotyped using TaqMan Genotyping Assays.

Results

In the allelic association analyses, rs868005 showed the strongest association with Type 2 PCV (allelic odds ratio 1.56; p = 7.4x10^-6), while no SNP was significantly associated with Type 1 PCV. Genotype association analyses revealed the significant association of rs868005 with Type 2 PCV in log additive model and predominant model (odds ratio 1.75; p = 1.5x10^-6 and odds ratio 1.60; p = 0.0044, respectively), but not with Type 1 PCV. These findings were further corroborated by another control group in the literature.

Conclusions

There may be significantly different associations in genetic variants of elastin between two angiographic phenotypes of PCV.

EVEREST study report 2: imaging and grading protocol, and baseline characteristics of a randomised controlled trial of polypoidal choroidal vasculopathy

Purpose

To describe the imaging standards, grading protocol and baseline characteristics of polypoidal choroidal vasculopathy (PCV) from the EVEREST study.

Methods

In a prospective, multicentre study, confocal scanning laser ophthalmoscope indocyanine green angiography (ICGA) was performed using a standardised imaging protocol. All images were graded using standardised, calibrated equipment by fellowship-trained ophthalmologists at the Central Reading Center.

Results

Sixty-one patients with PCV were included in the study. ICGA characteristics included: nodular appearance stereoscopically (56 eyes, 91.8%), hypofluorescent halo (42, 68.9%), abnormal vascular network (54, 88.5%) and pulsation of the polyps (4, 6.6%). Colour fundus photography revealed orange subretinal nodules (34, 55.7%) and massive submacular haemorrhage (8, 13.1%). The mean area of the PCV lesion was 3.11 mm² (range, 0.2–10.7 mm²). The vascular channels filled within 7.3–32.0 s (mean: 17.9 s) while the mean filling time for polyps was 21.9 s (range, 7.3–40.4 s). Patients with massive submacular haemorrhage were less likely to have abnormal vascular channels seen on ICGA (28.6% vs 83.3% for those without massive haemorrhage, p=0.001).

Conclusions

The imaging and grading protocols and baseline characteristics of a multicentre, randomised controlled trial of PCV are described in detail, and may serve as reference for future randomised, controlled trials on PCV.

Clinical trial number

This work was supported by Novartis Pharma AG, Basel, Switzerland grant number NCT00674323 (clinicaltrials.gov).

Systematic review and meta-analysis of the association between complement factor H I62V polymorphism and risk of polypoidal choroidal vasculopathy in Asian populations

Purpose

To investigate whether the polymorphism rs800292 (184G>A, I62V) in the complement factor H gene is associated with polypoidal choroidal vasculopathy (PCV) and the genetic difference between PCV and neovascular age-related macular degeneration (nAMD), in Asian populations.

Methods

A comprehensive literature search was performed in PubMed, Medline, Web of Science, and reference lists. A system review and meta-analysis of the association between I62V and PCV and/or nAMD were performed from 8 studies involving 5,062 subjects. The following data from individual studies were extracted and analyzed: 1) comparison of I62V polymorphisms between PCV and controls; 2) comparison of I62V polymorphisms between PCV and nAMD. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using fixed-effects models. The Q-statistic test was used to assess heterogeneity, and Egger’s test was used to evaluate publication bias. Sensitivity analysis and cumulative meta-analysis were also performed.

Results

The I62V polymorphism showed a significant summary OR₁ for genotype GA+GG versus homozygous genotype AA was 3.18 (95% CI, 2.51–4.04, P<0.00001), the OR₂ of heterozygous genotype GA versus AA was 2.29 (95% CI: 1.79–2.94, P<0.00001), the OR₃ of homozygous genotype GG versus AA was 4.42 (95% CI: 3.45–5.67, P<0.00001), and the OR₄ of allele G versus A was 2.04 (95% CI: 1.85–2.26, P<0.00001). Sensitivity analysis indicated the robustness of our findings, and evidence of publication bias was not observed in our meta-analysis. Cumulative meta-analysis revealed that the summary ORs were stable. There was no significant difference in every genetic model between PCV and nAMD (n = 5, OR₁ = 0.92, OR₂ = 0.96, OR₃ = 0.90, OR₄ = 0.94).

Conclusions

Our analysis provides evidence that the I62V polymorphism is associated with an increased risk of PCV. The variant of I62V could be a promising genetic biomarker of PCV in Asian populations.

Spectral domain optical coherence tomography analysis of macular changes in tilted disk syndrome

PURPOSE

To evaluate the prevalence of macular complications in tilted disk syndrome by spectral domain optical coherence tomography (OCT).

METHODS

A monocentric retrospective study of consecutive patients with tilted disk syndrome, whose eyes were examined by spectral domain OCT (Cirrus; Zeiss) and fundus photography.

RESULTS

Fifty consecutive patients (39 women and 11 men; age range, 41-96 years) with uni- or bilateral tilted disk syndrome were enrolled. All affected eyes (n = 92) were imaged by spectral domain OCT and fundus photography. Fluorescein and/or indocyanine green angiography were performed in 33 patients (66%). Macular anomalies or complications were observed in 71 eyes (77.1%). Specifically, retinal pigment epithelial changes were described in 34 eyes (36.9%), choroidal neovascularization in 24 eyes (26%), and macular serous retinal detachment in 16 eyes (17.3%). Epiretinal membrane in 9 eyes (9.7%), myopic foveoschisis in 5 eyes (5.4%), and lamellar macular hole in 3 eyes (3.2%) were also detected relatively frequently by spectral domain OCT. Surprisingly, fovea plana was observed in 5 eyes (5.4%). Eleven eyes, complicated by choroidal neovascularization, were treated with ranibizumab, with a mean visual gain of 7.9 letters on Early Treatment Diabetic Retinopathy Study chart.

CONCLUSION

Tilted disk syndrome can be associated with potentially severe macular complications. Spectral domain OCT allowed the recognition of additional macular changes associated with tilted disk syndrome, such as epiretinal membranes, myopic foveoschisis, and fovea plana.

Polypoidal choroidal vasculopathy: clinical features and genetic predisposition

Polypoidal choroidal vasculopathy (PCV) is currently recognized as a phenotype of age-related macular degeneration (AMD). PCV is believed to be a type of choroidal neovascularization, although some cases of PCV show a distinct vascular abnormality of the choroidal vessels. PCV often shows several unique clinical manifestations which are apparently different from typical neovascular AMD (tAMD). In addition, the natural course and response to treatment are often different between tAMD and PCV. Moreover, recent genetic studies suggested a possible difference in the genetic susceptibility to disease between tAMD and PCV, as well as the existence of heterogeneity among PCV cases. In viewing the accumulation of knowledge about PCV, we have summarized the recent literature regarding PCV in this review article to improve the understanding of this clinical entity including possible susceptibility genes. We will also discuss the optimal treatment strategies for PCV in accordance with the results of recent clinical and genetic studies.