P1209role of Ntprobnp in Long-Term Peritoneal Dialysis Patients

Abstract

Background and Aims Plasma N-terminal fragment of pro brain natriuretic peptide (NTproBNP) concentration is elevated in cardiovascular diseases such as congestive heart failure, where increased levels of NTproBNP indicate cardiac dysfunction, hypervolemia, and higher risk of hospitalization and death. These associations have also been studied in patients with chronic kidney disease (CKD), where NTproBNP value remains controversial, especially in long-term peritoneal dialysis (PD) patients with respect to its pathophysiologic implications. This study aim was to determine whether NTproBNP was a predictor of hospital admissions and cardiovascular events among patients on automated (APD) and continuous (CAPD) ambulatory peritoneal dialysis. Methods This was a cross-sectional study which included stable patients from two Peritoneal Dialysis Units. Plasma NTproBNP concentration was measured in stable adult peritoneal dialysis patients attending for routine assessments on PD outpatient clinic. In all patients, demographic variables, clinical and other laboratory parameters were recorded and analyzed. Descriptive statistics was performed. Groups were compared using independent t-test for comparison of continuous variables and Chi square test for categorical variables. In order to evaluate relationship between NTproBNP and the other variables multivariate logistic regression and Pearson bivariate analysis were used. Results The study enrolled 70 patients (male/female 44/26; mean age 55.3±14.6 years; APD/CAPD 25/45; PD duration 28±24.2months). One third (31.4%) of the patients was diabetic, 12.9% presented cardiac insufficiency and 20% had cardiovascular disease. Pearson bivariate correlation analysis revealed that patients with higher weekly kt/v (p=0.039), total fluid removal (diuresis and ultrafiltration) (p=0.027) and total weekly creatinine clearance (p=0.007) had lower NTproBNP values. These patients had also significant lower plasmatic creatinine and phosphorus levels. We found no significant association with residual kidney function, peritoneal transport (D/P creatinine), serum albumin levels and c-reactive protein. We also found that patients with higher NTproBNP levels had significantly more cardiovascular events (p=0.010) and a trend for more common hospital admissions (p=0.066). There were no significant differences regarding NTproBNP between the two modalities of peritoneal dialysis (APD and CAPD patients) or in patients who were PD first. As expected, patients with cardiac dysfunction had significant higher NTproBNP values (p=0.004). Diabetic patients had higher NTproBNP levels, althought this difference was not significant. Conclusion Despite the inconsistency in the NTproBNP value among long-term PD patients, results from most studies concur that NTproBNP levels are closely associated with left ventricular dysfunction, morbidity and mortality in these patients. In our study, patients with higher NTproBNP levels had more cardiovascular events and a trend for more common hospital admissions. Regular monitoring of NTproBNP levels among PD patients may be useful for providing care for these patients. Plus, NTproBNP was associated with better PD efficacy, greater fluid removal and higher creatinine clearance, reinforcing clinical relevance of PD optimization. These results require confirmation in a prospective study.