Abstract
Background
In chronic thromboembolic pulmonary hypertension (CTEPH), pulmonary artery obstruction leads to impaired pulmonary hemodynamics and secondary right heart failure, which is highly predictive of outcome. Thus, the extent of myocardial -especially right heart- remodelling is an indicator of disease severity.
Purpose
The aim of the present study was to assess growth differentiation factor-15 (GDF-15), galectin-3, and suppression of tumorigenicity 2 (ST2) as non-invasive biomarkers of myocardial remodelling in patients suffering from CTEPH.
Methods
We analysed the serum levels of GDF-15, galectin-3 and ST2 in a cohort of 64 CTEPH patients and in a control group of 25 patients without cardiovascular disease. The biomarker levels were further correlated with clinical, laboratory, and hemodynamic data, including 6-minute walking distance (6-MWD), N-terminal pro-brain natriuretic peptide (NT-proBNP), mean pulmonary artery pressure (meanPAP), pulmonary vascular resistance (PVR), and right atrial pressure (RAP).
Results
The biomarker levels in the control group were: galectin-3: 3.5 ng/l (IQR 2.7–4.0), GDF-15: 92.6 pg/ml (IQR 78.5–129.1), and ST2: 48.65 ng/l (IQR 35.5–57.0). CTEPH patients had higher levels of GDF-15 (196.7 pg/ml; IQR 128.4–302.8; p<0.001) and ST2 (52.6 ng/l; IQR 44.5–71.9; p=0.05) but not galectin-3 (3.4 ng/l; IQR 2.7–4.3; p=0.84). In the CTEPH cohort, patients with a meanPAP >35 mmHg (GDF-15: p=0.01; ST2: p=0.04) and patients with a PVR >500 dyn sec cm–5 (GDF-15: p=0.004; ST2: p=0.002) had significantly increased biomarker levels. For the detection of a meanPAP >35mmHg, ROC analysis revealed an AUC of 0.71 for GDF-15 and 0.67 for ST2. The level of GDF-15 correlated with the level of NT-proBNP (rrs=0.69; p≤0.001) and the RAP (rrs=0.54; p≤0.001) and inversely with the 6-MWD (rrs=−0.47; p≤0.001). The level of ST2 correlated with the level of NT-proBNP (rrs=0.67; p≤0.001) and the RAP (rrs=0.54; p≤0.001) and inversely with the 6-MWD (rrs=-0.31; p=0.02).
Conclusion
Our results demonstrate that GDF-15 and ST2, non-invasive biomarkers of myocardial remodelling, are significantly elevated in patients suffering from CTEPH. The correlation of biomarker levels with established outcome predictors suggests a use as indicators of disease severity.
A simple non-invasive diagnostic algorithm for ruling out chronic thromboembolic pulmonary hypertension in patients after acute pulmonary embolism
