Prevalence and Predictors of Pulmonary Arterial Hypertension in Hemoglobin E/ β-Thalassemia Patients.

Pulmonary arterial hypertension (PAH) associated with thalassemia (Thal) hemoglobinopathy is now an accepted clinical entity. Most of the reports are in sickle cell disease and splenectomized β-Thal patients. Once manifested, it connotes poor prognosis. We herein present its prevalence and predictors in hemoglobin E/β-Thal (E/β-Thal) patients.

One hundred and ten clinically stable E/β-Thal outpatients, on no medication aside from folic acid and who received no blood transfusion in the preceding 4 weeks were studied. All gave written informed consent, and study protocol was approved by the institution ethics committee on studies in humans (#0774/2548). Echocardiogram was used to estimate systolic PA pressure (SPAP). PAH was defined as an estimated SPAP ≥36 mmHg. Clinical features and laboratory data were stratified according to the presence or absence of PAH, and statistical analysis was done by STATA version 10 (Stata Corp, Texas), considering a P value <0.05 as statistically significant. Predictors of PAH were considered in univariate analysis.

There were 110 patients, 56 of whom were female and 61 were asplenic. PAH was present in 41 patients (37.3%), all of whom had normal left ventricular ejection fraction. There was no gender difference between the 2 groups (p=0.055). Selected statistically significant results are shown in the table.

Prevalence of PAH in E/β-Thal patients is 37.3% without gender preponderance. Predictors are asplenia, more severe hemolysis, higher number of circulating (activated) platelets and nucleated RBCs, increased chronic low grade inflammation and increased cellular adhesion between blood and endothelial cells. These changes could facilitate development of thrombotic pulmonary arteriopathy, the underlying basis of PAH. Serum NT pro BNP assay can be utilized as a predictor or a screener of PAH in these patients.

No relevant conflicts of interest to declare.