Prevalence, determinants and prognosis of pulmonary hypertension among hemodialysis patients

Background. The prevalence, determinants and prognosis of pulmonary hypertension among long-term hemodialysis patients in the USA are poorly understood. Methods. A cross-sectional survey of prevalence and determinants of pulmonary hypertension was performed, followed by longitudinal follow-up for all-cause mortality. Pulmonary hypertension was defined as an estimated systolic pulmonary artery pressure of >35 mmHg using echocardiograms performed within an hour after the end of dialysis. Results. Prevalent in 110/288 patients (38%), the independent determinants of pulmonary hypertension were the following: left atrial diameter (odds ratio 10.1 per cm/m(2), P < 0.0001), urea reduction ratio (odds ratio 0.94 per %, P < 0.01) and vitamin D receptor activator use (odds ratio 0.41 for users, P < 0.01). Over a median follow-up of 2.15 years, 97 (34%) patients died yielding a crude mortality rate (CMR) of 114.2 per 1000 patient-years. Of these, 58 deaths occurred among 110 patients with pulmonary hypertension (53%, CMR 168.9/1000 patient-years) and 39 among 178 without pulmonary hypertension (22%, CMR 52.5/1000 patient-years) [unadjusted hazard ratio (HR) for death 2.12 (95% confidence interval 1.41-3.19), P < 0.001]. After multivariate adjustment, pulmonary hypertension remained an independent predictor for all-cause mortality [HR 2.17 (95% confidence interval 1.31-3.61), P < 0.01]. Conclusions. Among hemodialysis patients, pulmonary hypertension is common and is strongly associated with an enlarged left atrium and poor long-term survival. Reducing left atrial size such as through volume control may be an attractive target to improve pulmonary hypertension. Improving pulmonary hypertension in this group of patients may improve the dismal outcomes.