Idiopathic pulmonary arterial hypertension (iPAH) is a fatal disease due to subsequent development of severe right heart failure. Right ventricular diastolic dysfunction may contribute substantially to the grim prognosis of the disease. However the diastolic properties of the failing right ventricle are poorly understood. We investigated whether right ventricular diastolic stiffness, marker of diastolic dysfunction, is increased in iPAH and if this alteration correlates with disease severity.Methods
1) Right heart catheterization (RHC) and cardiac MRI were performed in 21 iPAH patients and 7 controls. Individual diastolic stiffness (β) was quantified by the curvature of the non-linear diastolic pressure-volume relation. 2) Subsequently, we investigated if diastolic stiffness was associated with disease severity. Stroke volume (SV), mean right atrial pressure (mRAP), 6 minutes walk-test (6MWT) and NYHA class were recorded and their median value was calculated. Patients with lower than median value SV and 6MWT and higher mRAP and NYHA class were considered clinically more severe.Results
1) Diastolic stiffness was significantly increased in iPAH patients (iPAH β=0.05 ± 0.005 vs. Con β=0.02 ± 0.003, p=0.013). 2) Severe groups had higher diastolic stiffness (Lower SV β=0.07 ± 0.001 vs Higher SV β=0.02 ± 0.002, p0.05).Conclusions
This study demonstrates that right ventricular diastolic stiffness is increased in iPAH patients and is associated with disease severity.