Chronic thromboembolic pulmonary hypertension (CTEPH) represents an important differential diagnosis to idiopathic pulmonary arterial hypertension (IPAH). We hypothesised that the capillary to end-tidal carbon dioxide gradient at rest and during exercise might help differentiate CTEPH from IPAH.Patients who presented with unequivocal IPAH or CTEPH according to ventilation/perfusion scanning, pulmonary angiography, computed tomography and right heart catheterisation were included in this retrospective study and compared with healthy controls.21 IPAH patients and 16 CTEPH patients fulfilled the inclusion criteria. Haemodynamics and peak oxygen uptake were comparable, but respiratory rates at rest and during exercise were significantly higher in CTEPH than in IPAH. End-tidal carbon dioxide was significantly lower in CTEPH versus IPAH at rest and during exercise, while capillary carbon dioxide values were similar. Correspondingly, capillary to end-tidal carbon dioxide gradients were significantly increased in CTEPH versus IPAH at rest and during exercise (median (range) 8.6 (3.0-13.7) versus 4.4 (0.9-9.0) (p,0.001) and 9.3 (3.3-13.1) versus 4.1 (0.0-8.8) mmHg (p,0.001), respectively). Although these values were closer to normal in IPAH they were still significantly elevated compared with healthy controls (2.3 (-4.8-8.1) and -1.9 (-5.7-6.2) mmHg, respectively).Capillary to end-tidal carbon dioxide gradients may help to distinguish CTEPH from IPAH based on resting and exercise values.

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Background: We assessed if cardiac blood markers are associated with motor and cognitive function in patients with Parkinson's disease (PD). Methods: High-sensitivity troponin I and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were evaluated in 285 PD patients. Furthermore, N-terminal

Background: Treatment with sphingosine-1-phosphate (S1P) agonists confers neuroprotective effects in animal models of Parkinson's disease (PD).Objectives: We assessed the association of serum S1P levels with motor and cognitive symptoms in patients with PD. Methods: S1P concentrations were analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS) in serum of 196 PD patients and in 196 age-and sex-matched controls. Motor (Unified Parkinson's disease rating scale III [UPDRS III], Hoehn and Yahr) and cognitive (Montreal Cognitive Assessment [MoCA]) function were assessed at baseline. Follow-up data was available from 64 patients (median [interquartile range], 513 [381-677] days). Results: S1P levels were lower in PD patients compared with controls, that is 1.75 (1.38-2.07) and 1.90 (1.59-2.18) μmol/L, respectively (P = 0.001). In PD patients, lower S1P concentrations were associated with higher UPDRS III scores and Hoehn and Yahr stage. In the follow-up cohort, S1P concentrations below the median were associated with faster motor decline (hazard ratio: 4.78 [95% CI, 1.98, 11.50]), but not with cognitive worsening. Conclusions: Our observations reveal an association of S1P with PD.