Measured vs estimated renal function on cardiovascular outcomes in an acute heart failure population

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Complejo Hospitalario Universitario de Canarias, Tenerife -Spain. Background/Introduction HF syndrome is a highly prevalent disease which courses with frequent readmissions, mainly by Acute Heart Failure (AHF). Worsening renal function is associated with increased mortality in patients with HF. Therefore, an accurate and precise evaluation of renal function in patients with HF is crucial. The error of estimated GFR (eGFR) is wide and common, showing ±30% of variability compared to measured GFR (mGFR). However, there is no evidence on the error of the available formulas in reflecting real renal function and particularly the consequences of this error in patients with AHF. Methods This is a prospective pilot study comparing measured versus estimated renal function and its relationship with long-term cardiovascular (CV) outcomes in patients with AHF. A group of patients with AHF who required admission in the CICU were included. Plasma clearance of iohexol, a gold-standard method to mGFR was assessed at the same time as eGFR by five different creatinine- and cystatin c–based equations. The association between estimated or measured GFR and major CV outcomes was evaluated with univariate and multivariate logistic analysis and cox-survival analysis. The main outcome was the first onset of fatal and nonfatal major cardiovascular events during follow-up. Results A total of 90 patients were included. Average age was 66 (± 12 years) and 52 (57,8%) were male. A total of 53 patients (59%) had a cardiovascular event during follow-up, being fatal in 22 cases (41,5%). Other variables are shown in Table 1. None of eGFR was significantly associated with the primary outcome in the unadjusted analyses. In the adjusted regression models, mGFR was significantly associated (p 0,037) with major cardiovascular events when it was correlated with NTproBNP, BMI, LVEF and previous coronary artery disease. mGFR on admission predicts future CV events compared with eGFR based on creatinine or cystatin equations. eGFR overestimates renal function showing around ±20% variability of mGFR in our AHF population (Figure 1). Conclusions Frequently used eGFR formulas in our daily practice in AHF patients do not predict well long-term cardiovascular outcomes. Measured GFR in AHF admission predicts CV events, while eGFR reflects an important variability of the real renal function. Specific subpopulations of AHF may require better evaluation of renal function because it may have prognosis consequences.