Predicting survival in pulmonary arterial hypertension in the UK.

Contemporary prognostic equations in pulmonary arterial hypertension (PAH) derived from US and French cohorts may not perform as well in the UK as a locally derived scoring scheme. The aim of the study was to develop and validate a UK risk score to predict prognosis in PAH. Baseline mortality predictors identified by multivariate Cox analysis in 182 incident PAH patients were used to derive the Scottish composite score (SCS). Its prognostic performance in an independent UK cohort was compared with the French registry and Pulmonary Hypertension Connection (PHC) registry equations using Brier scores (BS). The SCS based on age, sex, aetiology, right atrial pressure, cardiac output and 6-min walk distance predicted survival in the validation cohort (hazard ratio (HR) 1.7 per point increase; p<0.001) and provided further prognostic stratification in World Health Organization (WHO) functional class III patients (HR 1.8 per point increase; p<0.001). It was more accurate than the French registry equation in predicting 1-yr survival (BS: 0.092 versus 0.146; p=0.001) and 2-yr survival (0.131 versus 0.255; p<0.001). There was no significant difference in BS between the SCS and PHC registry equation. The SCS predicts survival and can be used to supplement WHO functional class in prognostication.

Use of non-invasive haemodynamic measurements to detect treatment response in precapillary pulmonary hypertension.

BACKGROUND: Haemodynamic measurements may be superior to the 6-min walk distance (6MWD) as outcome measures in pulmonary hypertension (PH) as they are directly linked to the mechanisms of disease and are not subject to a ceiling effect. The aim of this study was to determine if treatment response in precapillary PH could be detected by pulmonary blood flow (PBF) and stroke volume (SV) measured non-invasively by the inert gas rebreathing (IGR) method at rest and during submaximal constant-load cycle exercise. METHODS: Twenty-four patients with precapillary PH receiving de novo or modified disease-targeted therapy were studied. Isotime metabolic variables, PBF and SV were measured at rest and during constant-load cycle exercise at 40% maximal work rate alongside conventional outcome variables, at baseline and after 3 months of new therapy. RESULTS: At follow-up there was a significant increase in PBF (supine rest: mean 0.7±SD 0.9 l/min, erect rest: 0.7±0.8 l/min, exercise: 0.8±1.0 l/min, p<0.005) and SV (supine rest: 7±10 ml, erect rest: 10±11 ml, exercise: median 6 (IQR 3-11) ml, p<0.005). There was a trend for 6MWD to increase by 17±42 or 29 (13-47) m (p=0.061), whereas WHO functional class, N-terminal pro-brain natriuretic peptide or Cambridge Pulmonary Hypertension Outcome Review score were unchanged. In patients with higher baseline 6MWD, IGR measurements were more sensitive than 6MWD in detecting treatment response. CONCLUSIONS: Non-invasive IGR haemodynamic measurements could be used to detect treatment response in patients with precapillary PH and may be more responsive to change than 6MWD in fitter patients.