Purpose: Patients with eosinophilic granulomatosis with polyangiitis (EGPA) most commonly die from cardiac causes, however, cardiac involvement remains poorly characterised and the relationship between cardiac and pulmonary disease is not known. This study aimed to characterise myocardial and pulmonary manifestations of EGPA, and their relationship.
Methods: Prospective comprehensive cardiopulmonary investigation, including a novel combined cardiopulmonary magnetic resonance imaging (MRI) technology, was performed in 13 patients with stable EGPA. Comparison was made with 11 prospectively recruited matched healthy volunteers.
Stable EGPA was associated with focal replacement and diffuse interstitial myocardial fibrosis (myocardial extracellular volume 26.9% vs. 24.7%; p=0.034), which drove a borderline increase in left ventricular mass (56 ± 9g/m2 vs. 49 ± 8 g/m2; p=0.065). Corrected QT interval was significantly prolonged and was associated with the severity of myocardial fibrosis (r=0.582, p=0.037). Stable EGPA was not associated with increased myocardial capillary permeability or myocardial oedema. Pulmonary tissue perfusion and capillary permeability were normal and there was no evidence of pulmonary tissue oedema or fibrosis. Forced expiratory volume in one second showed a strong inverse relationship with myocardial fibrosis (r=-0.783, p=0.038).
In this exploratory study, stable EGPA was associated with focal replacement and diffuse interstitial myocardial fibrosis, but no evidence of myocardial or pulmonary inflammation or pulmonary fibrosis. Myocardial fibrosis was strongly associated with airway obstruction and abnormal cardiac repolarisation. Further investigation is required to determine the mechanisms underlying the association between heart and lung disease in EGPA and whether an immediate immunosuppressive strategy could prevent myocardial fibrosis formation.