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Título

Increased foveal avascular zone in Chagas Disease reinforces vascular-mediated hypothesis: a cross-sectional study

Resumo

Introduction: Chagas Disease (CD) is associated with cerebral atrophy, silent cerebral microembolism, stroke, and cognitive dysfunction in patients with heart failure (HF), all independently of HF severity. Two theories were proposed to explain these associations: microvascular damage and/or neurodegeneration. The vascular and nerve fiber layers of the retina are assessable non-invasively using Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCT-A), which may be useful to understand if the pathophysiology of CD is vascular- or neurodegenerative-mediated.
Objective: To investigate the association between CD and abnormalities detected in OCT and OCT-A.
Methods: Cross-sectional study from a prospective cohort of individuals aged ≥ 18 years, fulfilling Framingham criteria for HF. CD was defined by a positive ELISA or immunofluorescence test performed in duplicate. Exclusion criteria were diabetes mellitus, pregnancy, glaucoma, previously diagnosed retinal diseases, or stroke. We performed OCT and OCT-A in patients between 2020-2022 and excluded tests with exam quality <50%. We conducted a univariate analysis considering the mean of both eyes.
Results: We included 32 patients with CD and 20 without CD. Baseline clinical characteristics were similar for both groups except for a higher frequency of females (88% vs 50%) and higher ejection fraction (mean 65.5% ± 9.2 vs mean 41.0% ± 19.5) among patients with CD. In OCT, the foveal thickness was lower in CD patients (mean 230 µm ± 18.1) compared to those without CD (mean 241 µm ± 24.7), but not statistically significant (p=0.13). No difference was noticed in the thickness of retinal nerve fiber or ganglion cell layers. Regarding OCT-A, the superficial plexus foveal vessel density was lower in CD patients (mean 12.9% ± 5.10) compared to those without CD (mean 16.6% ± 4.23), with p=0.02. The deep plexus foveal vessel density in CD (mean 26.7% ± 7.10) was lower than in patients without CD (mean 30.8% ± 6.21) but not with statistical significance (p=0.05). There was no difference in vessel density considering the whole image, perifoveal or papillary regions.
Conclusion: Chagas disease was associated with decreased foveal vascular density, but no changes in nerve fiber or ganglion cell layers of the retina. This finding is common to microvascular retinopathies, suggesting that CD may damage microcirculation beyond neuroimaging-detected damage with tests such as magnetic resonance imaging.

Palavras Chave

Chagas Disease, Optical Coherence Tomography, Optical Coherence Tomography Angiography

Área

Doença Cerebrovascular