Right ventricular functions in subphenotypes of sickle cell disease

Sickle cardiomyopathy is the most important cause of death in patients with sickle cell disease (SCD). Based on recent evidence, SCD can be divided into two subphenotypes, namely, the viscosity vasoocclusion (VVO) subphenotype and the hemolysis endothelial dysfunction (HED) subphenotype. The aim of our series is to study right ventricular (RV) functions in both subphenotypes.

Echocardiography including conventional and tissue Doppler imaging as well as speckle tracking echocardiography was performed in 50 patients (23 from the VVO subgroup and 27 from the HED subgroup) based on a serum lactate dehydrogenase (LDH) level below or above 270 U/L, respectively, and in 50 controls. Reticulocyte count and hemoglobin levels were assessed in different groups of patients.

The HED subgroup showed RV dysfunction. Patients in this subgroup also showed systolic and diastolic functions similar to those seen in the VVO subgroup and controls. In addition, a tight correlation exists between LDH and both RV global longitudinal strain (-0.68) and RV E/E' ratio (0.9), defined as the ratio of early diastolic tricuspid inflow velocity to tricuspid annular early diastolic velocity.

Results reveal a marked discrepancy in RV functions between HED and VVO subphenotypes of SCD, with patients in the former subgroup being more prone to RV dysfunction. This warrants early screening of such patients in daily practice.