[Pulmonary hypertension in hemodialysis patients: Prevalence and associated factors]

Pulmonary hypertension (PH) is a progressive disorder that can be caused by several underlying conditions or an intrinsic alteration of the pulmonary vasculature. Chronic increased pressure in the pulmonary vasculature leads to changes in the architecture of the vessels that can perpetuate PH and produce right ventricular dysfunction. These structural and functional alterations can decrease survival and quality of life of patients on hemodialysis; however, there is a lack of evidence about this problem in this population. The aim of this study is to establish the prevalence of PH in patients on hemodialysis and its association with specific factors related to this patient population.

We included 202 prevalent patients on hemodialysis for at least 6 months and who were clinically stable. We collected demographic data, routine laboratory parameters and data of 2D Doppler-echocardiography. PH was defined as a systolic pulmonary artery pressure (SPAP) estimated by Doppler ultrasound above 35mmHg. Hydration status was assessed by determining the plasma concentration of N-terminal pro brain natriuretic peptide (Nt-proBNP).

PH prevalence was 37.1% (75 patients). The average SPAP in the entire study population was 32±12mmHg and in the group with PH it was 45±11mmHg. We found a direct and statistically significant correlation between the presence of PH and age (P=.001), time on renal replacement therapy (P=.04), the presence of systolic dysfunction (P=.007), diastolic dysfunction (P= 01), mitral valve disease (P=.01) and double mitral and aortic disease (P=.007). Volume overload was closely associated with PH, as demonstrated by the correlation between the SPAP and Nt-proBNP levels (P=.001).

We conclude that prevalence of PH in hemodialysis patients is high. And one of the most important associated factors is volume overload. More studies are needed to establish the impact of PH on morbidity and mortality of patients and to assess whether a better volume control improves PH.