Eye test may help to detect AAV damage before symptoms evident
Poorer blood vessel density seen in retina of patients without vision issues
Subclinical changes are evident in the small blood vessels in the back of the eye and in the nails of people with ANCA-associated vasculitis (AAV) that are not associated with overt eye or nail symptoms, a study showed.
Notably, a reduced blood vessel density in patients’ eyes, assessed via noninvasive imaging, significantly associated with higher scores in the Vasculitis Damage Index (VDI), which measures accumulated damage in 11 organ systems.
Findings suggest that a noninvasive eye test may be useful in detecting early microvascular damage in people without overt AAV symptoms or evidence of eye involvement, possibly helping to diagnose the disease at presymptomatic stages and to better manage patients, the researchers noted.
The study, “Subclinical microvascular changes in ANCA-vasculitides: the role of optical coherence tomography angiography and nailfold capillaroscopy in the detection of disease-related damage,” was published in the Orphanet Journal of Rare Diseases.
Optical coherence tomography angiography captures blood vessels in retina
AAV is an autoimmune disease characterized by inflammation that damages small to medium blood vessels, affecting tissue and organ function.
Two noninvasive techniques — optical coherence tomography angiography (OCT-A) and nailfold videocapillaroscopy (NFC) — are of increasing interest for assessing subclinical blood vessel changes in people with systemic autoimmune or inflammatory diseases.
Subclinical changes are those not causing overt symptoms.
OCT-A is used to visualize blood vessels in the retina, the back layer of the eye that houses light-sensing cells, while NFC allows researchers to analyze microvascular changes under the fingernail.
However, evidence is limited on subclinical blood vessel changes in the eyes and nails of people with AAV, as assessed using these techniques.
“The prevalence of microvascular retinal changes, particularly in a pre-symptomatic phase, has not been thoroughly investigated in AAV patients,” the research team at the University of Rome Tor Vergata in Italy wrote. Likewise, “an increasing focus has emerged on the usefulness of the non-invasive microvascular examination also at the nailfold bed in the context of several systemic diseases.”
“Interestingly,” it’s being given to people with diabetes, arterial hypertension, and glaucoma, they added.
These scientists analyzed results of both techniques in 23 people with AAV and no other co-occurring health problems, and in 20 healthy adults as a control group.
Patients’ mean age was 60.9 years, and they had been living with the disease for a mean of 9.6 years. Lung involvement was the most common disease manifestation, followed by ear-nose-throat involvement. The mean age of control group was 57.9.
Patients had good visual acuity, but notably lower retinal blood vessel density
Visual acuity and pressure within the eye in AAV patients was similar to that of healthy people. However, OCT-A results showed that patients had significantly lower blood vessel density in both the superficial and deep retina compared with controls.
A significant inverse correlation also existed between retinal blood vessel density and the Vasculitis Damage Index, a standardized measure used to assess blood vessel damage in AAV, in which higher scores indicate more damage.
In other words, patients with fewer blood vessels in the superficial and/or deep retina tended to have higher VDI scores and more AAV-associated damage.
As expected, patients’ VDI scores significantly correlated with the Birmingham Vasculitis Activity Score, a measure of AAV severity, and with the Five-Factor Score, which is used to predict outcomes in people with AAV.
“We documented for the first time subclinical microvascular changes in retinal vascular network from AAV patients and described significant correlations between vessel density abnormalities and AAV-disease damage,” the researchers wrote.
They speculated that this type of analysis may be useful for identifying early signs of vessel damage in patients who don’t have pronounced symptoms, which could aid in early diagnoses and in guiding treatment decisions.
Optical coherence tomography angiography as way to detect eye issues in AAV
“Our data support the utility of the OCT-A as a non-invasive tool to the early detection of retinal vascular abnormalities in AAV patients in whom both the cardiovascular and the complement-mediated inflammation might lead to retinal damages,” the researchers wrote.
Its use also may allow for “an accurate detection of disease-damage, and a more tailored treatment and management of such rare and [complex] patients,” they added.
Scientists also noted that this was a small analysis done at a single center, so larger studies are needed to validate these results and further explore the clinical utility of these retinal measurements.
Results of nailfold videocapillaroscopy showed nonspecific abnormalities in nail blood vessels in most AAV patients (82.6%) and healthy controls (75%). No significant associations were found between microvascular nail changes and scores of disease activity measures.
The potential utility of analyzing nail blood vessels in AAV “requires further studies,” the team concluded.