Inferior Vena Cava Dilatation Predicts Mortality and Worsening Renal Function in Patients With Chronic Heart Failure

Abstract

Although heart failure is thought to cause worsening renal function (WRF) through hypo perfusion secondary to a reduction in cardiac output, there is evidence to suggest that renal venous congestion may also be a contributing factor. Invasive studies have shown that central venous pressure predicts WRF in heart failure patients with a preserved cardiac output; however, non-invasive studies investigating this relationship are scarce. Potentially, assessment of inferior vena cava (IVC) diameter can be used to estimate venous congestion, as raised right arterial pressures dilate the IVC making it non-collapsible. We therefore aimed to investigate the association between IVC diameter and outcomes, including WRF, heart failure hospitalisations and all-cause mortality. We conducted a retrospective cohort study of 1,078 chronic heart failure (CHF) patients from the BIOSTAT-CHF Scotland study. All CHF patients were symptomatic, requiring the use of loop diuretics, and were optimally treated on recommended therapy for CHF. Venous congestion (VC) was defined as IVC diameter >2.1cm, identified from echocardiography at baseline review. Renal function was determined by estimated glomerular filtration rate (eGFR) using the abbreviated MDRD equation. Logistic regression models were used to examine the association between VC and eGFR. Cox proportional hazard models were applied to examine the influence of VC on all-cause mortality and CHF hospitalisations. Multivariate analysis showed that those with VC had significantly worse survival than those without VC after adjusting for age, sex, eGFR and furosemide daily dose (hazard ratio [HR]: 1.6, 95% CI: 1.2-2.1; p=0.01). Although time to first CHF hospitalisation was shorter for the VC group compared to those without VC, this was not a statistically significant difference. Logistic regression models showed that those with severe renal impairment (eGFR60 (Odds Ratio=7.7 (1.6-37.5), p=0.012)). IVC width as an indirect measurement of renal venous congestion predicts worse survival in CHF and is associated with severe renal impairment. As an easily obtainable non-invasive predictor of renal venous congestion, IVC diameter could therefore be a potentially useful marker for both renal function and overall prognosis in CHF patients.