MO722: Cardiac Biomarkers (NT-proBNP, Troponin I) and Heart Failure in Haemodialysis Patients

Abstract BACKGROUND AND AIMS Patients with chronic kidney disease (CKD) stage 5 on haemodialysis are at a high risk of cardiovascular disease according to 10-year estimation validated risk models (SCORE system) [1, 2]. Cardiac biomarkers, such as N-terminal pro-BNP (NT-proBNP) and troponin I (Tn-I), have been studied in this population enabling patient classification and prediction of cardiovascular morbimortality in chronic haemodialysis [3–5]. The primary objective of this study is to determine serum levels of the cardiac biomarkers NT-proBNP and TnI, and to evaluate the relationships between ecocardiographic signs of heart failure and its treatment, and to identify those patients in chronic haemodialysis at the highest cardiovascular risk. METHOD We performed an observational, descriptive study in patients on maintenance haemodialysis at our haemodialysis unit (n = 118). We collected different data: gender, age, dialysis vintage and etiology of CKD. We examined medical records and transthoracic echocardiography reports of the last year and classified patients according to heart failure diagnosis (yes/no). Levels of NT-proBNP were divided into three categories with different cut-off points: group 1 (<50-year-old, NT-proBNP < 450 pg/mL), group 2 (50–75-year-old, NT-proBNP < 900 pg/mL), group 3 (>75-year-old, NT-proBNP < 1800 pg/mL). TnI levels were considered positive above 20 pg/mL in all age groups. RESULTS Participants’ mean age was 64.65 ± 2.84 years, and 62.7% were identified as male. The mean age was 4.4 years older in women (67.43 years in women and 62.92 years in men). A total of 66.9% of patients had started renal replacement therapy in the last 5 years. The most common etiology of CKD (number of patients) was diabetes (31) followed in decreasing order by unknown (22), glomerular disease (18), hypertension (13), hereditary disease (8), systemic disease (4) and other kidney and urologic disorders (22). The diagnosis of heart failure stated by medical records and echocardiography was positive only in 26.27% (31 patients), thus the 73.73% (87 patients) did not present that diagnosis. Of those 31 patients with heart failure, 26 patients had raised NT-proBNP levels, in accordance with their predefined age-group (group 1, 2 or 3). On the other hand, 77 (or 65% of the total sample) of the 87 patients without clinically diagnosed heart failure had elevated cardiac biomarkers that could support a heart failure diagnosis, not previously stated in their medical history. Tn-I levels were positive in 35% (39 patients) without dyspnea, chest pain or other heart disease symptoms. CONCLUSION In conclusion, cardiac biomarkers allowed us to broaden the diagnostic process of heart failure and to identify those patients at a higher cardiovascular risk. Our results suggest the majority of patients of our haemodialysis unit would benefit of a closer monitoring, with echocardiography and assessment of serum cardiac biomarkers.