Pulmonary hypertension in patients on chronic hemodialysis

Abstract Introduction Pulmonary hypertension (PH) is a common condition in patients with advanced chronic kidney disease and is associated with higher morbidity and mortality. High arteriovenous fistula (AVF) flow is one of known etiological factors, but the association of AVF flow within the acceptable range and PH has not been tested. Moreover, the prevalence of PH differed among various studies. Purpose The aims of this study were: 1. to describe the prevalence of PH in the Czech hemodialysis population; 2. to analyze the relation between dialysis fistula flow and PH; 3. to reveal other etiology of PH in a cross-sectional non-invasive trial. Methods We analyzed index visits of the cohort CZecking HF-CKD study (ISRCTN 18275480). Thus, this is a cross-sectional analysis based on detailed echocardiography with cardiac output (CO) calculation, evaluation of the central venous pressure (CVP) and AVF flow, bio-impedance and basic laboratory tests. All these measurements were done within an hour. The presence of PH was based on the peak systolic pulmonary arterial pressure (PASP) estimation above 35 mmHg. Results We analyzed data of 162 patients. They were 73,2 ± 12,6 years old, dialysis vintage 30 ± 69 months. Pulmonary hypertension was present in 35 % of analyzed patients. Among these patients, mild PH was present in 35 %, moderate in 53 % and severe in 12 %. There was no significant impact of AVF/AVG flow on the presence of PH or PASP value (Table 1.). However patients with PH had higher prevalence of heart failure (HF), which was present in 86 % of patients with PH and only in 46 % without PH (p<0.00001), see Figure 1. This and other differences presented in Table 1. document significant contribution of postcapillary PH. Patients with PH were also more overhydrated when considered by CVP, by overhydration measurement using bioelectrical impedance analysis and had higher N-terminal pro brain natriuretic peptide (NTproBNP) (Table 1.). There was a positive correlation between systemic vascular resistance (SVR) and PASP (R=0,333, p= .001). Conclusions PH is present in approximately one third of the dialysis patients. The presence of heart failure and changes of left heart chambers show for the postcapillary etiology of PH. Neither the prevalence nor the severity of PH were significantly related to arteriovenous access flow.