Heart failure and kidney disease share common pathophysiological pathways which can lead to mutual dysfunction, known as cardiorenal syndrome. In heart failure patients, renal impairment is related to hemodynamic and non-hemodynamic factors. Both decreased renal blood flow and renal venous congestion due to heart failure could lead to impaired renal function. Kidney disease and worsening renal function are independently associated with poor prognosis in heart failure patients, both in acute and chronic clinical settings. The aim of this review is to assess the role of renal imaging modalities in the evaluation and management of heart failure patients. Renal imaging techniques could complete laboratory data, as estimated glomerular filtration rate, exploring different pathophysiological factors involved in kidney disease and adding valuable information about renal structure and function. In particular, Doppler examination of arterial and venous hemodynamics is a feasible and non invasive technique, which has proven to be a reliable method for prognostic stratification in patients with cardiorenal syndrome. The renal resistance index, a measure related to renal hemodynamics, can be calculated from the Doppler evaluation of arterial flow. Moreover, the analysis of Doppler venous flow patterns can integrate information from the arterial study and evaluate renal congestion. Other imaging modalities are promising, but still confined to research purposes.
Keywords: Cardiorenal syndrome; Chronic kidney disease; Doppler; Heart failure; Hemodynamics; Prognosis; Renal resistance index; Venous Doppler.