Published July 13, 2017 | Blood

Clinicians have long known that people with sickle cell anemia (SCA) often face the risk of early death from heart disease. However, until recently, much about how SCA causes heart damage has remained unknown.

Now a study led by Omar Niss, MD, and Charles Quinn, MD, MS, has uncovered a potentially major underlying cause that also can be detected and tracked through non-invasive cardiac magnetic resonance (CMR) scanning.

“We found that diffuse myocardial fibrosis is a common feature in SCA that appears to predate the development of diastolic dysfunction,” the co-authors wrote.

SCD appears to cause normal heart muscle cells to be replaced with a scattering of fibrous tissue, which in turn enlarges the heart and disrupts its pumping capacity. The researchers used CMR T1-mapping to measure how this process affects extracellular volume fraction (ECV).

“ECV was markedly increased in all participants, including young children, and even in the absence of focal fibrosis. In addition, higher fibrosis was associated with diastolic dysfunction and the restrictive physiology features of the SCA-related cardiomyopathy,” the co-authors say.

The new findings suggest that people with SCA may benefit from treatment with anti-fibrotic agents. However, the authors say that further confirmation of the association between elevated fibrosis and poor heart function is needed from larger-cohort studies. This observational study’s limitations included a relatively small sample size—25 patients—and a lack of established guidelines for classifying diastolic dysfunction in children.

Investigators at Cincinnati Children’s are conducting a longitudinal study to evaluate the progress of diffuse myocardial fibrosis in SCA. Pending that data, “Our results highlight an important, novel, and previously under-recognized mechanism of heart pathology in SCA, and demonstrate the feasibility of non-invasive myocardial fibrosis assessments in children and adults with SCA.”