Clinical presentation and prognostic impact of eosinophilic myocarditis associated to eosinophilic granulomatosis with polyangiitis

Background

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis characterized by asthma, eosinophilia, and multi-organ involvement. Cardiac manifestations—ranging from pericardial effusion to eosinophilic myocarditis—represent one of the most severe complications, significantly influencing prognosis. Despite recent advances in diagnosis and immunomodulatory therapy, the clinical features and outcomes of cardiac involvement (CI) in EGPA remain incompletely defined.

Purpose

To characterize CI in EGPA, compare CI with non-cardiac involvement (nCI), and explore prognostic implications in a contemporary multicenter cohort.

Methods

retrospective bicenter study including 53 EGPA patients: CI, n=26; nCI, n=27. Baseline demographics, biomarkers, echocardiography, cardiac magnetic resonance (CMR), and endomyocardial biopsy (EMB) were analyzed. Group comparisons used standard parametric/non-parametric tests.

Results

At diagnosis, mean age was 50.5±15.7 years; males 45.3%. Traditional risk factors were balanced. At the time of EGPA diagnosis, patients with CI exhibited a significantly higher rate of hospitalization (p < 0.001), with cardiac symptoms representing the predominant cause for admission (p < 0.06). CI presentation had lower LVEF on TTE (42.83±15.92% vs 59.67±4.51%; p=0.002) and more pericardial effusion (61.5% vs 0%; p=0.011). Within CI, severe presentations were frequent: complicated course 91.7%, cardiogenic shock 24.0%, fulminant form 28.0%; temporary MCS in 15.4%. Median admission troponin was 133.47×URL (IQR 4.98–310.93); NT-proBNP 6632±5493 pg/mL. Eosinophilia at entry likewise showed no significant between-group difference (peak eosinophil count p=0.169). Compared with nCI, ANCA-positive patients were less likely to have CI at diagnosis (8.3% vs 50.0%; p=0.016).

EMB demonstrated eosinophilic myocarditis in 76% of biopsied cases (median 10 days from hospitalization). CMR confirmed myocarditis in 83.0% of CI; LGE was present in 90.9%, predominantly subendocardial (65.0%) with predominance of septal involvement. Follow-up (FU) was longer in nCI than CI (13 vs 3.5 years; p<0.001). Disease control at fixed timepoints and peak eosinophil counts were similar between groups. At last FU mortality during FU was low and not significantly different (3.7% nCI vs 11.5% CI; p=0.351).

Conclusions

In EGPA, CI is a clinically severe phenotype with characteristic CMR and supportive EMB findings. In patients presenting with CI, cardiac symptoms are the predominant cause of initial hospitalization, which subsequently leads to the diagnosis of EGPA.

Despite low mortality under contemporary care, residual systolic dysfunction is more common in CI. While baseline systemic features appear largely comparable between CI and nCI, a routine cardiac screening of the whole cohort, with a specific focus on patients with cardiac symptoms, and longitudinal follow-up are warranted.Characteristics of EGPA patientsFor image description, please refer to the figure legend and surrounding text.EGPA diagnosis and LGE distributionFor image description, please refer to the figure legend and surrounding text.