Pulmonary Arterial Hypertension in b-thalassemia

Abstract

Abstract :

Background : Pulmonary arterial hypertension (PHT) is a not uncommon cardiac complication in splenectomized b-thalassemia (b-Thal). Its prevalence in b-Thal and factors associated with it in Thai patients have been unknown. Methods : A cross-sectional study was conducted in b-Thal patients in the Hematology Outpatient Clinic at Ramathibodi hospital during Jan 1999 to Nov 2003. Pulmonary artery systolic pressure (PASP) was determined by doppler echocardiography. PHT was defined as PASP ≥ 40 mmHg. Characteristics of the PHT and non-PHT groups were compared and analyzed. Results : Eighty-eight patients were included: splenectomized 65 (hemoglobin E/b-thalassemia (E/b-Thal) 61, homozygous b-Thal 4) and non-splenectomized 23 (E/b-Thal 22, homozygous b-Thal 1). PHT was detected in 43 (49%) patients (E/b-Thal 42, homozygous b-Thal 1). The PHT group had a higher proportion than the non-PHT group for splenectomy 36 (84%) vs. 7 (16%), p=0.04), and a higher percentage of nucleated red blood cells (nRBCs) to WBC (534/100WBC vs. 228/100WBC, p<0.01). In the splenectomized patients, the percentage of nRBCs was higher in the PHT than the non-PHT group (720/100WBC vs. 404/100WBC, p<0.01), but it was not different in the non-splenectomized patients (11/100WBC vs. 4/100WBC, p=0.38). There were no statistically significant differences in gender, age, post-splenectomy duration, hemoglobin concentration, white blood cell counts, platelet counts, and serum ferritin levels between the PHT and non-PHT group. In a multivariate analysis, features significantly associated with PHT were post splenectomy status (OR 2.83[1.02-7.82]), and nRBCs ≥500/100WBC (OR 3.49[1.24-9.8]). Conclusions : The prevalence of PHT in b-Thal disease in our study was 49%. Factors associated with PHT were post splenectomy status and nRBC ≥500/100WBC.