Manifestations cardiaques du syndrome hyperéosinophilique essentiel

Loeffler's Endocarditis: An Integrated Multimodality Approach

Loeffler's endocarditis (LE) is the cardiac manifestation of hypereosinophilic syndrome, a rare systemic disease characterized by the sustained production of eosinophils leading to organ damage. Few data, principally by case reports, are available regarding the diagnostic workup in patients with suspected LE. Thus, we have performed a systematic search of the literature dealing with imaging in LE and propose an integrated multimodality imaging approach in the cardiac diagnostics of LE patients. The aim is to provide an updated state-of-the-art review focused on noninvasive and invasive imaging modalities for this rare and underdiagnosed disease. Standard and advanced echocardiography are typically the first cardiac imaging examinations when LE is suspected and they are also used later in follow-up for prognostic stratification and assessing response to treatment. Cardiac magnetic resonance provides a more detailed anatomical and functional evaluation of cardiac chambers, tissue characterization for the presence and extension of myocardial edema and fibrosis, and ventricular thrombi identification. Computed tomography scan and [18F]-fluoro-deoxy-glucose positron emission tomography may be helpful in selected cases to evaluate the cardiac involvement of LE as well as the other noncardiac manifestations of hypereosinophilic syndrome. Endomyocardial biopsy may be considered in patients with high clinical suspicion of LE if noninvasive imaging findings are confusing or not conclusive. The appropriate use of invasive and noninvasive imaging modalities, combining the available techniques with the patients' clinical features, will hopefully lead to early diagnosis, more accurate staging of disease, and timely treatment of LE that may prevent the irreversible myocardial damage of LE and adverse cardiovascular events.

Hypereosinophilic cardiac disease

Hypereosinophilia may be due to several aetiologies. Cardiac complications are not uncommon, whatever the causes. Clinical presentations of hypereosinophilic cardiac diseases may vary widely from asymptomatic form to fatal necrotic myocarditis or irreversible restrictive cardiomyopathy. As a major cause of morbidity and mortality, diagnosis of cardiac involvement is crucial. Until recently the diagnosis was exclusively based on cardiac biopsy. Nowadays, multimodal cardiac imaging, including echocardiography and cardiac magnetic resonance imaging, is the cornerstone of the diagnosis. Cardiac magnetic resonance imaging has emerged as a very useful tool for the diagnosis allowing precise tissue characterization. It has even been proposed as a surrogate to cardiac biopsy. It should be systematically performed in case of hypereosinophilia. Early and appropriate treatment is crucial to avoid the evolution toward irreversible cardiac lesions. These treatments are symptomatic but should also be adapted to the underlying diseases.

[Hematological disorders and hypereosinophilias]

Hematological disorders are the third cause of hypereosinophilia, after allergic and parasitic diseases. Hematological disorders associated with hypereosinophilias can be classified as clonal, reactive or idiopathic, and recently the improvements of cytogenetic, molecular biology and immunology have allowed to revisit numerous cases previously diagnosed as idiopathic hypereosinophilic syndrome. Reactive eosinophilias are mainly associated with lymphoma or abnormal, often clonal T lymphoid population. Clonal eosinophilia is related either to various myeloid malignancies or to a genuine myeloproliferative disorder from the eosinophile lineage, the so-called chronic eosinophilic leukaemia. Chronic eosinophilic leukaemia can be associated with recurrent genes rearrangements involving PDGFRA, PDGFRB and FGFR1 or with clonal abnormalities not yet categorized. Idiopathic hypereosinophilic syndrome remains an exclusive diagnosis in presence of moderate or severe unexplained eosinophilia with target organ damage. The purpose of the diagnostic work-up of hypereosinophilic syndrome is to evidence either an abnormal T cell population or a clonal haematopoiesis. Imatinib mesylate dramatically improves chronic eosinophilic leukaemias associated with PDGFR abnormalities, while corticosteroids are still the main treatment for the other patients. In a near future, advances could arise from identification of new genes involved in clonal eosinophilia or in alternative therapy such as the anti-IL-5 antibodies.