Prevalence of pulmonary hypertension in an unselected, mixed connective tissue disease cohort: results of a nationwide, Norwegian cross-sectional multicentre study and review of current literature

Objectives. The aim of this study was to assess the overall prevalence of pulmonary hypertension (PH) in an unselected MCTD cohort and review the current knowledge with a systematic database search. Methods. A nationwide multicentre cohort of 147 adult MCTD patients were initially screened for PH by echocardiography, high-resolution computed tomography (HRCT), pulmonary function tests and N-terminal pro-brain natriuretic peptide (NT-proBNP) and then followed up for a mean of 5.6 years. Right-sided heart catheterization was performed when estimated pulmonary artery systolic pressure was > 40 mmHg on echocardiography. PH was diagnosed according to the 2009 European Society of Cardiology and European Respiratory Society guidelines. Results. At inclusion, 2.0% (3/147) had established PH. Two additional PH patients were identified during follow-up, giving a total PH frequency in the cohort of 3.4% (5/147). All five had elevated serum NT-proBNP. Two had isolated pulmonary arterial hypertension (PAH) and three PH associated with interstitial lung disease (PH-ILD). Three PH patients died during follow-up. Nine other patients in the cohort also died, but none of them had echocardiographic signs of PH prior to death. Conclusion. The data from the current unselected MCTD cohort suggest that the prevalence of PH is much lower than expected from previous studies but confirm the seriousness of the disease complication.