Heart Biopsy May Help Diagnose EGPA in ANCA-negative Cases

Patricia Inacio, PhD avatar

by Patricia Inacio, PhD |

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A biopsy of heart muscle may aid in the diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA) with cardiac involvement in patients negative for antineutrophil cytoplasmic antibodies (ANCAs) and with a negative skin biopsy, a case study suggests.

The study, “Endomyocardial biopsy facilitates diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA): a case report,” was published in the journal Cardiovascular Pathology.

EGPA is a form of ANCA-associated vasculitis (AAV) where immune cells called eosinophils mistakenly attack small blood vessels in the lungs and gastrointestinal tract, leading to asthmalike symptoms. The disease may also affect other organs in the body, including the heart.

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A skin biopsy is typically used as a standard diagnostic test to confirm damaging inflammation in small blood vessels. While cardiac involvement is linked to a poor prognosis, its presence is difficult to diagnose.

Now, researchers at the University of Texas Medical Branch have described the case of a patient with EGPA with cardiac involvement, who was diagnosed with the aid of an endomyocardial biopsy.

The patient, a 55-year-old Hispanic man, came into the emergency room with chest pain accompanied by exercise-associated collapse, abnormal sweating, and heart palpitations. He also reported fatigue, chills, night sweats, and weight loss over the past two months, along with other symptoms. He reported no alcohol consumption and no steroid or medication use.

His medical history included, among other conditions, chronic rhinosinusitis, adult-onset asthma, high blood pressure, and high levels of fatty molecules in the bloodstream, as well as cocaine and methamphetamine abuse. He had no family history of heart disease.

A first electrocardiogram showed evidence of a heart attack, called non-ST segment elevation myocardial infraction, which is caused by a partial or complete blockage of a cardiac artery.

Lab tests showed signs of inflammation (elevated levels of C-reactive protein), as well as high numbers of white blood cells, including eosinophils. The levels of NT-proBNP — a heart damage biomarker – were also elevated.

Blood tests for ANCA antibodies were negative, and a bone marrow biopsy showed no signs of elevation and infiltration of eosinophils.

Although ANCA levels were normal and a skin biopsy lacked evidence of EPGA, the patient underwent an endomyocardial biopsy after nine days of being admitted to the hospital. This is an invasive procedure to collect and analyze a small sample of the heart’s muscle.

The biopsy, analyzed by two pathologists, revealed eosinophils-mediated inflammation accompanied by leaking small blood vessels, consistent with a diagnosis of EGPA.

He began treatment with high doses of steroids delivered directly into the bloodstream and was later started with the oral immunosuppressant azathioprine. He was already on a combo of medications for his heart condition, which included daily beta-blockers, angiotensin-converting-enzyme (ACE) inhibitors, and diuretics.

EGPA therapy led to a rapid drop in his eosinophil counts and eased his shortness of breath. His condition continued to improve, and he was discharged on oral steroids and azathioprine.

Overall, this case report suggests that “even in the setting of a negative skin biopsy, there should be high clinical suspicion for EGPA in a patient who presents with a combination of allergic rhinitis, asthma, eosinophilia [high number of eosinophils], and acute myocardial injury,” the researchers wrote.

“Eosinophilic infiltrates in heart biopsies, while not specific on their own, can have value in reaching a clinical diagnosis when combined with clinical features,” they wrote.