Hypereosinophilic syndrome: considerations for the cardiologist

Abstract

Eosinophil-mediated endomyocardial damage is a well-known complication in patients with hypereosinophilic syndromes (HES). Although management and survival have improved significantly, some patients continue to develop severe cardiomyopathy as a direct consequence of uncontrolled hypereosinophilia. Cardiologists play a key role in early detection and treatment. At the early generally asymptomatic stage, related to subendocardial eosinophilic infiltrates, elevation of the biomarker of cardiac damage (serum troponin) and cardiac MRI are the best tools for diagnosis. As disease progresses, patients typically develop intracardiac mural thrombi and may experience variable degrees of heart failure due to valve damage and/or subendocardial fibrosis, all of which are more readily detectable with traditional echocardiographic investigation. New imaging modalities such as strain imaging and specific sequences in MRI offer the perspective of detecting subtle perturbations and distinguishing inflammatory versus fibrotic stages. Endomyocardial biopsy may help in difficult settings, namely, when blood eosinophilia is not prominent, but may be non-contributive due to sampling issues or eosinophil degranulation or replacement by fibrosis, and must always be performed after careful consideration of the risk:benefit ratio. Although treatment of the HES itself should be managed by clinicians with expertise in this rare disorder with the aim of lowering eosinophil counts to prevent and treat eosinophil-mediated organ damage and dysfunction, cardiologists play a key role in managing the associated cardiopathy. There are no consensual disease-specific guidelines for treating eosinophil-mediated thrombotic complications and cardiopathy, which should be managed according to classical international recommendations.

Immunomodulating Therapies in Acute Myocarditis and Recurrent/Acute Pericarditis

“…The natural history of eosinophil-related heart involvement involves three successive (and potentially overlapping) phases: (1) AM, due to eosinophilic infiltration of the endocardium, that can be either asymptomatic or lead to acute HF or FM ( 137 ). High troponin levels, LV systolic dysfunction, and subendocardial LGE pattern on CMRI can be observed ( 2 , 137 ) a thrombotic stage characterized by the occurrence of ventricular thrombi and the risk of systemic embolism; ( 3 ) a fibrotic stage, characterized by endomyocardial fibro-thrombosis that can lead to restrictive cardiomyopathy (i.e., Loeffler cardiomyopathy) and/or atrioventricular valvular disease ( 139 ). The diagnosis of eosinophilic myocarditis is usually straightforward in the presence of hypereosinophilia, increased cardiac troponin, and CMRI consistent with subendocardial inflammation ( 137 ).…”

“…The diagnosis of eosinophilic myocarditis is usually straightforward in the presence of hypereosinophilia, increased cardiac troponin, and CMRI consistent with subendocardial inflammation ( 137 ). EMB can be considered when the initial presentation is characterized by cardiogenic shock ( 1 , 33 ), or CMRI findings are atypical (i.e., subepicardial LGE) or when absolute eosinophil counts are within the normal range (which has been reported in up to 25% of patients with biopsy-proven eosinophilic myocarditis) ( 137 , 139 ). Conversely, EMB is at risk of thromboembolism if ventricular thrombi are present, and can yield false-negative findings when endomyocardial fibrosis is prominent and eosinophil infiltration has partially or completely vanished ( 138 ).…”

“…The cornerstone of the treatment relies on systemic glucocorticoids, starting dose: 1 mg/kg qd, preceded in case of severe LV systolic dysfunction by intravenous pulses of 7.5–15 mg/kg of methylprednisolone for 1–3 days ( Figures 1 , 3 ) ( 137 , 139 ). In patients at risk of strongyloidiasis (owing to their past travel history), concomitant prescription of a single dose of ivermectin (200 μg/kg) is warranted to prevent Strongyloides stercoralis hyperinfection.…”

Hypereosinophilic syndrome and eosinophilic granulomatosis with polyangiitis: Eosinophilic-associated inflammatory conditions with a challenging diagnosis and treatment

“…We would also like to draw attention to the damage to the cardiac structure caused by eosinophils. Unfortunately, despite great improvements in management and survival, some patients continue to develop severe cardiomyopathy and heart failure [2,5]. We would like to emphasize that cardiologists play a fundamental role in the early detection and treatment of these conditions.…”

“…New imaging modalities, such as strain imaging and particularly cardiac magnetic resonance imaging sequences, give the possibility of identifying minor changes and discriminating between inflammatory and fibrotic processes. Endomyocardial biopsy can be useful in problematic situations, but it may be ineffective due to sampling difficulties, eosinophil degranulation, or fibrosis replacement and must always be performed after a careful assessment of the risk-benefit balance [5]. The nature of clinical manifestations arising from eosinophil-related organ dysfunction should influence the choice of treatment [2].…”