Congestion guided hemodialysis: results from the CONGHeRA study

Abstract Background Congestion is a central determinant of outcomes in end-stage kidney disease (ESKD) patients undergoing haemodialysis (HD). Inferior vena cava maximum caliper (IVC-max) and its collapsibility index (IVC-CI), together with extracellular-intracellular volume (ECW-ICW) estimated by bioimpedance analysis (BIA), are widely used to assess fluid status, but their prognostic accuracy is limited. Coronary sinus (CS) diameter assessed by echocardiography has recently emerged as a novel non-invasive marker of systemic venous congestion. A post-dialysis absolute maximum CS diameter (CS-max) >9 mm has also been demonstrated to be an independent and significant predictor of mortality. Methods Single-centre prospective study. From October 2023, 35 ESKD patients were randomized into a treatment group (N=19) and a control group (N=16) at the Nephrology Unit of the University Hospital of Padua. All patients underwent serial echocardiographic and bioimpedance evaluations at regular intervals and were followed until June 2025. In the treatment group, the dialysis protocol was regularly adjusted according to CS-max, with increased ultrafiltration if CS-max > 9 mm. The control group received standard dialysis independently of CS-max. Primary outcomes were mortality and major adverse cardiovascular events (MACE). Results Over a mean follow-up of 15 ± 3.4 months, mortality (1 vs 3) and MACE (3 vs 5) were lower in the treatment group, although differences did not reach statistical significance (HRMACE 0.32, 95% CI 0.05–1.87, p=0.21). All deaths were sepsis-related, predominantly pneumonia. CS-max significantly correlated with ECW (r=0.41), IVC-max (r=0.54) and IVC-CI (r=-0.54, p<0.001). Residual diuresis emerged as a key determinant of congestion. Patients with residual diuresis had higher CS-max and ECW, reflecting less aggressive ultrafiltration (p<0.01). In control group, on serial measurements, patients without residual diuresis showed a significant increase in CS-max (p=0.03). Conclusions CS-max is a reliable marker of congestion and may serve as a tool for individualized fluid management. While the congestion-guided approach appears safe and potentially beneficial, validation in larger multicentre studies is required.