title: Pulmonary hypertension in non-transfusion-dependent thalassemia: Correlation with clinical parameters, liver iron concentration, and non-transferrin-bound iron.
abstract: BACKGROUND
  Pulmonary hypertension is a major cardiac complication in non-transfusion-dependent thalassemia (NTDT). Several clinical and laboratory parameters, including iron overload, have been shown to have a positive correlation with the incidence of pulmonary hypertension. Non-transferrin-bound iron (NTBI) is a form of free-plasma iron that is a good indicator of iron overload.
  
  
  OBJECTIVE
  The aim of this study was to determine the prevalence of pulmonary hypertension in patients with NTDT and to investigate its correlation with the clinical parameters, liver iron concentration (LIC) and NTBI.
  
  
  METHODS
  Patients with NTDT were evaluated using echocardiography, and magnetic resonance imaging for cardiac T2* and LIC. Pulmonary hypertension was deﬁned as peak tricuspid regurgitation velocity ≥2.9 m/s measured using trans-thoracic echocardiography. Clinical parameters and the status of iron overload as determined by LIC, serum ferritin, and NTBI level were evaluated for their association with pulmonary hypertension.
  
  
  RESULTS
  Of 76 NTDT patients, mean age 23.7 ± 8.5 years, seven patients (9.2%) had pulmonary hypertension. Previous splenectomy (71.4 vs. 24.6%, P-value 0.019), higher cumulative red blood cell (RBC) transfusions (received ≥10 RBC transfusions 85.7 vs. 33.3%, P-value 0.011), higher nucleated RBCs (353 ± 287 vs. 63 ± 160/100 white blood cells, P-value <0.001), and a high NTBI level (5.7 ± 3.0 vs. 3.3 ± 2.8 µmol/l, P-value 0.034) were associated with pulmonary hypertension. There was no significant correlation between LIC or serum ferritin and pulmonary hypertension.
  
  
  CONCLUSIONS
  Pulmonary hypertension in NTDT is common, and is associated with splenectomy and its related factors. NTBI level shows a significant correlation with pulmonary hypertension.
authors.forename: Kunrada
authors.initials: K
authors.lastname: Inthawong
authors.forename: Pimlak
authors.initials: P
authors.lastname: Charoenkwan
authors.forename: Suchaya
authors.initials: S
authors.lastname: Silvilairat
authors.forename: Adisak
authors.initials: A
authors.lastname: Tantiworawit
authors.forename: Arintaya
authors.initials: A
authors.lastname: Phrommintikul
authors.forename: Worawut
authors.initials: W
authors.lastname: Choeyprasert
authors.forename: Rungrote
authors.initials: R
authors.lastname: Natesirinilkul
authors.forename: Chate
authors.initials: C
authors.lastname: Siwasomboon
authors.forename: Pannee
authors.initials: P
authors.lastname: Visrutaratna
authors.forename: Somdet
authors.initials: S
authors.lastname: Srichairatanakool
authors.forename: Nipon
authors.initials: N
authors.lastname: Chattipakorn
authors.forename: Torpong
authors.initials: T
authors.lastname: Sanguansermsri
mesh_terms: D000293:Adolescent; D000328:Adult; D001803:Blood Transfusion; D002648:Child; D004452:Echocardiography; D005260:Female; D005293:Ferritins / Q000097:blood / Q000378:metabolism; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology*; D007501:Iron / Q000097:blood / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D013789:Thalassemia / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism / Q000628:therapy; D055815:Young Adult
chemical_list: D005293:Ferritins; D007501:Iron
keywords: Iron overload; Non-transferrin-bound iron; Non-transfusion-dependent thalassemia; Pulmonary hypertension