BackgroundChronic inflammation emerges as a feature of the pathogenesis of pulmonary arterial hypertension (PAH) in experimental models. Alterations of circulating cell subsets have been observed in patients with PAH. We aimed to assess associations of the white blood cell count with disease severity and outcome in patients with PAH.MethodsThe total and differential white blood cell count was related to functional parameters, pulmonary hemodynamics and transplantation-free survival in 77 patients with PAH in an observational single center study.ResultsAn increased neutrophil/lymphocyte ratio was associated with poor World Health Organization functional class and shorter 6-minute walking distance, as well as with elevated right atrial pressure and high level of N-terminal prohormone of brain natriuretic peptide. During a median follow-up period of 31 months (range 16-56) 23 patients died and 2 patients were referred to lung transplantation. Using uni- and subsequent bivariate Cox proportional hazards analyses an increased neutrophil/lymphocyte ratio was associated with unfavorable transplantation-free survival independent of hemodynamic parameters and C-reactive protein. The prognostic implication sustained in subsets of patients with incident PAH and in the absence of cardiovascular risk factors.ConclusionsThe results of this analysis indicate that a neutrophilic inflammation may be associated with clinical deterioration and poor outcome in patients with PAH. Assessing the composition of the differential white blood cell count may render prognostic information and could represent a step towards incorporating an inflammatory marker into the clinical management of patients with PAH.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-017-0407-5) contains supplementary material, which is available to authorized users.

Background: Right ventricular (RV) dysfunction is a major prognostic predictor in pulmonary arterial hypertension (PAH). Objectives: The objective of this study was to assess the prognostic impact of a newly developed index merging haemodynamic parameters into 1 variable. Methods: We retrospectively assessed 2 cohorts of 248 patients (164 from Hamburg and 84 from Heidelberg) with invasively diagnosed PAH. During a median follow-up time of 3.6 years (3.1 and 4.0 years for Hamburg and Heidelberg, respectively), the composite endpoint of all-cause mortality and lung transplantation occurred in 57 patients (53 and 4 patients for Hamburg and Heidelberg, respectively). The RV index was developed in the Hamburg cohort and validated in the Heidelberg cohort: (right atrial pressure × pulmonary vascular resistance)/mixed venous oxygen saturation. Results: Patients with a high RV index had a higher incidence of the combined endpoint in Kaplan-Meier analyses in the Hamburg and Heidelberg cohort (p = 0.017 and p = 0.034, respectively). The calculated RV index cut-off value was 91 and identified patients with a worse outcome in the Hamburg cohort and showed a trend in the Heidelberg cohort (p < 0.001 and p = 0.089, respectively). The RV index in Cox regression hazard models was an independent predictor of outcomes after adjustment for sex and age in both cohorts (Hamburg: hazard ratio [HR] 1.26 [95% CI 1.08, 1.47], p = 0.0027; Heidelberg: HR 2.27 [95% CI 1.46, 3.51], p < 0.001). A nomogram based on these results allowed risk stratification. Conclusion: Merging 3 haemodynamic variables into 1 variable, the RV index increased the prognostic power up to an independent risk factor. The RV index is easy to calculate and allows the construction of a nomogram for an individualized risk assessment.