Prevalence and Risk Factors for Pulmonary Arterial Hypertension in a Large Group of β-Thalassemia Patients Using Right Heart Catheterization: A Webthal® Study
Background—Pulmonary arterial hypertension (PAH) remains a concern in patients with β-thalassemia major (TM) and intermedia (TI); however, studies evaluating its prevalence and risk factors using systematic confirmation on right heart catheterization are lacking.
Methods and Results—This was a multicenter cross-sectional study of 1309 Italian β-thalassemia patients (mean age 36.4 ± 9.3 years; 46% men; 74.6% TM, 25.4% TI). Patients with a tricuspid-valve regurgitant jet velocity (TRV) ≥3.2 m/s (3.6%) on transthoracic echocardiography further underwent right heart catheterization to confirm the diagnosis of PAH (mean pulmonary arterial pressure ≥25 mm Hg and pulmonary capillary wedge pressure ≤15mm Hg). The confirmed PAH prevalence on right heart catheterization was 2.1% (95%CI: 1.4-3.0); and was higher in TI (4.8%, 95%CI: 3.0-7.7) than TM (1.1%, 95%CI: 0.6-2.0). The positive predictive value for the TRV ≥3.2 m/s threshold for the diagnosis of pulmonary hypertension was 93.9%. Considerable functional limitation and decrease in the 6-minute walk distance were noted in patients with confirmed PAH. On multivariate logistic regression analysis, independent risk factors for confirmed PAH were age (OR: 1.102 per 1-year increase, 95%CI: 1.06-1.15) and splenectomy (OR: 9.31, 95%CI: 2.57-33.7).
Conclusions—The prevalence of PAH in β-thalassemia patients as confirmed on right heart catheterization was 2.1%, with a ~5-fold higher prevalence in TI than TM. Advanced age and splenectomy are risk factors for PAH in this patient population.
Clinical Trial Registration Information—ClinicalTrials.gov. Identifier: NCT01496963.
- Received February 20, 2013.
- Revision received September 20, 2013.
- Accepted September 23, 2013.