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The heart in sickle cell anemia. The Cooperative Study of Sickle Cell Disease (CSSCD)
W Covitz1, M Espeland, D Gallagher
1Sickle Cell Disease Branch, National Heart, Lung, and Blood Institute, Bethesda, Md, USA.
Insights
Stable sickle cell disease patients show enlarged heart chambers and thickened septa, with normal contractility. Left ventricular size relates inversely to hemoglobin and is influenced by age, indicating no specific sickle cell cardiomyopathy.
Area of Science:
- Cardiology
- Hematology
- Medical Imaging
Background:
- Sickle cell disease (SCD) can affect cardiac structure and function.
- Previous studies yielded conflicting echocardiographic results, possibly due to patient selection.
Purpose of the Study:
- To determine representative echocardiographic measurements of cardiac size and function in stable sickle cell disease patients.
- To investigate factors influencing cardiac dimensions in SCD.
Main Methods:
- Prospective, multicenter study with central, blinded echocardiogram reading.
- Inclusion of stable outpatients with SS phenotype across diverse settings and age ranges.
- Measurement of biventricular dimensions, wall thickness, atrial and aortic root size, and systolic time intervals.
Main Results:
- Body surface area-indexed chamber dimensions and septal thickness were significantly increased compared to normal.
- Chamber dimensions and wall thickness (except right ventricle) inversely correlated with hemoglobin levels.
- Left ventricular dimension showed a significant age-dependent relationship with hemoglobin.
- Systolic time interval ratios were normal, but left ventricular ejection time was prolonged.
- Shortening fraction was normal; velocity of circumferential fiber shortening was low.
Conclusions:
- Stable sickle cell disease patients exhibit cardiac chamber dilation and septal hypertrophy with preserved overall contractility.
- Left ventricular dilation is inversely related to hemoglobin and significantly influenced by age (disease duration).
- No specific cardiomyopathy is identified in sickle cell anemia patients based on these echocardiographic findings.
Abstract:
The objective of this study was to obtain representative echocardiographic measurements of cardiac size and function in stable patients with sickle cell disease. This prospective, multicenter study utilized central reading of echocardiograms by an investigator blinded to other patient data. Stable outpatients from a balance of inner city and rural settings with SS phenotype and a broad age range were selected, because conflicting results from earlier studies were believed to be due to these patient selection criteria. Right and left ventricular dimensions and wall thickness, left atrial and aortic root dimensions, and systolic time intervals were measured. Body surface area indexed chamber dimensions and septal thickness were significantly increased from normal. Except for the right ventricle, chamber dimensions and wall thickness were inversely correlated with hemoglobin. The relationship between left ventricular dimension and hemoglobin was significantly dependent on age. Systolic time interval ratios were normal though left ventricular ejection time was prolonged. Shortening fraction was normal but velocity of circumferential fiber shortening was abnormally low. Stable patients with sickle cell disease have dilated chambers, septal hypertrophy, and normal contractility. Though left ventricular dilatation was inversely related to hemoglobin, age (duration of illness) was an important factor in that relationship. No specific cardiomyopathy was associated with sickle cell anemia.