Pulmonary hypertension in well-transfused thalassemia major patients

Abstract

The risk for pulmonary hypertension (PH) in thalassemia major (TM) patients remains controversial. We report echocardiography results from 60 TM patients: we evaluated the association between tricuspid regurgitation velocities (TRV), iron stores, and serologic markers of hemolysis and arginine dysregulation. Patients were enrolled from August 2004 until May 2009. All parameters were inversely weighted by the number of exams. TRV was comparable between sexes and it was uncorrelated with age. At the first exam, TR velocities at the upper limits of normal (2.5-2.7m/s) were observed in 8 patients. An abnormal TRV (2.9m/s) was found in 1 patient. Borderline increases in TRV were associated with a reduced global arginine bioavailability (R=-0.399 P=0.005), increased anemia (hemoglobin: R=-0.219 P=0.0461), cardiac index (R=0.223 P=0.0481), and diastolic dysfunction (E/A: R=0.289 P=0.0088; E/E': R=0.223 P=0.0453), but not hemolysis, iron overload and systolic function evaluated by Magnetic Resonance Imaging, and splenectomy. Well-transfused TM patients have a lower risk for PH than thalassemia intermedia patients. However, they do have vascular stressors that raise their lifetime PH risk to levels higher than for the general population. Consequently, we support recommendations for annual echocardiographic screening and cardiac catheterization for persistent TRV above 3m/s.

Keywords: Echocardiography; Risk for pulmonary hypertension; Thalassemia major; Tricuspid regurgitant jet velocity.

Figure 1

Scatter plot and fitted regression line showing the relationship between TRV and global arginine bioavailability (GAB). Thresholds proposed by Morris et al. are shown; no patient has decreased GAB.

Figure 2

Scatter plot and fitted regression line showing the relationship between TRV and hemoglobin (up) and between TRV and cardiac index (bottom).

Figure 3

Scatter diagram and regression line of TRV compared to E/A ratio (up) and E/E′ ratio (bottom); E/E′ > 10 is considered evidence of diastolic dysfunction.