Abstract 587: Impaired Renal Function is not only related to Decreased Cardiac Output but also to Increased Venous Pressure in Patients with Cardiac Dysfunction
Introduction: Glomerular filtration rate (GFR) is an important prognostic variable in chronic heart failure (CHF). CHF is associated with increased venous congestion and decreased cardiac output. The latter results in decreased renal blood flow (RBF). While the relationship between RBF and GFR is well established, little is known about the relationship between venous congestion and GFR.
Hypothesis: We assessed the hypothesis that venous congestion plays a significant contributing role in determining renal function in patients with cardiac dysfunction.
Methods: We studied 51 patients (30% male, mean age 40 ± 11 years), with cardiac dysfunction due to pulmonary hypertension. Right heart catheterisation was done to investigate right atrial pressure (RAP), mean pulmonary artery pressure, pulmonary vascular resistance (PVR) and cardiac index. GFR and RBF were measured by iothalamate and hippuran clearances, respectively.
Results. Mean age was 40 ± 11 years and 69% of patients was female. Mean GFR was 73 ± 19 ml/min/1.73m2 with a mean cardiac index of 2.1 ± 0.7 l/min/m2. In univariate analysis, RBF, RAP, cardiac index and PVR were related to GFR. In multivariate analysis, RBF ( r = 0.664, p < 0.001) and RAP (r = − 0.367, p < 0.020) were independently associated with GFR, accounting for 61% of the variability in GFR. Especially in patients with lower values of RBF, increased RAP was an important determinant of GFR (Figure⇓).
Conclusion. RBF remains the most important factor associated with GFR in patients with cardiac dysfunction. However, especially in patients with low RBF, venous congestion indicated by an increased RAP plays a significant role in predicting GFR.