Systemic inflammation is associated with pulmonary hypertension in patients undergoing haemodialysis

Background. Pulmonary hypertension (PH) is an overlooked cardiovascular morbidity in patients undergoing haemodialysis. Inflammation has been demonstrated to play a significant role with certain types of PH in non-uraemic patients, but studies analysing the mechanisms in dialyzed patients with PH are rare. Hence, we investigated systemic and local inflammation biomarkers associated with PH in uraemia patients to elucidate the potential mechanism. Methods. A cross-sectional study was conducted in which 97 haemodialysis patients were initially evaluated in our hospital. Twelve inflammatory cytokines were measured using a cytometric beads assay in patients with and without PH. FENO (fractional exhaled nitric oxide) was checked by a chemiluminescence analyser in patients with and without PH as well as by normal controls. Results. Thirty-nine eligible patients were enrolled. Compared to patients without PH (group A), patients with PH (group B) had significantly higher serum levels of hs-CRP, IL-1 beta, TNF-alpha and IL-6. FENO was also measured. Though the pre-dialysis FENO levels were elevated in both groups; group B patients had significantly higher pre-dialysis FENO levels than group A patients (39.9 +/- 16.7 versus 31.8 +/- 10.3, P = 0.045). The post-dialysis FENO levels returned to normal in group A while the remaining were significantly higher in group B (30.3 +/- 10.3 versus 20.1 +/- 10.9, P = 0.003). Conclusions. Our study revealed that dialyzed patients with PH had a significantly higher level of airway FENO as well as serum levels of acute phase reactive protein and cytokines, including IL-1 beta, TNF-alpha and IL-6. A chronic inflammation might play an important role in the pathogenesis of PH in patients undergoing haemodialysis.