Association between diffuse myocardial fibrosis and diastolic dysfunction in sickle cell anemia

Area of Science:

• Cardiology
• Hematology
• Medical Imaging

Background:

• Sickle cell anemia (SCA) related cardiomyopathy presents with diastolic dysfunction, a predictor of mortality.
• The underlying cause of diastolic dysfunction in human SCA remains unclear, despite evidence of fibrosis in animal models.
• Understanding the mechanisms of SCA cardiomyopathy is crucial for improving patient outcomes.

Purpose of the Study:

• To quantify diffuse myocardial fibrosis using cardiac magnetic resonance (CMR) extracellular volume fraction (ECV) in individuals with SCA.
• To determine the association between diffuse myocardial fibrosis and diastolic dysfunction in SCA patients.
• To explore correlations between ECV, diastolic function, hemoglobin levels, and NT-proBNP.

Main Methods:

• Cardiac magnetic resonance imaging (CMR) was used to measure extracellular volume fraction (ECV) in 25 individuals with SCA.
• ECV was calculated from pre- and post-gadolinium T1-weighted imaging of blood and myocardium.
• Diastolic function was assessed using echocardiography, and NT-proBNP levels were measured.

Main Results:

• All participants with SCA showed markedly increased ECV compared to controls, indicating diffuse myocardial fibrosis.
• Diastolic dysfunction was present in 29% of patients, and these individuals had significantly higher ECV and NT-proBNP levels.
• Higher ECV values correlated with lower hemoglobin levels and higher NT-proBNP, and were associated with increased left atrial volume.

Conclusions:

• Diffuse myocardial fibrosis, detected by ECV, is a prevalent and previously unrecognized feature of SCA.
• This myocardial fibrosis is significantly associated with diastolic dysfunction, anemia, and elevated NT-proBNP in SCA patients.
• Diffuse myocardial fibrosis represents a novel mechanism underlying diastolic dysfunction in sickle cell anemia.