Intrarenal venous flow in cardiorenal syndrome: a shining light into the darkness.

The aim of this case report is to assess the potential role of intrarenal Doppler ultrasonography as a non-invasive method to evaluate intrarenal venous flow (IRVF) in acute heart failure (AHF) and concomitant renal dysfunction. We report a case of an 81-year-old woman with valvular heart disease (previous mitral valve replacement) that presented with acutely decompensated heart failure and concomitant worsening renal function (WRF). In addition to complete physical examination, laboratory analysis, and echocardiography, IRVF was assessed at baseline and 48 h after the administration of diuretic treatment. At admission, physical examination and echocardiography revealed signs of intravascular congestion (jugular venous distension and severely dilated inferior vena cava). In addition, a significant increase in serum creatinine from 1.23 to 1.81 mg/dL was noted without signs of hypoperfusion at clinical evaluation. At baseline, intrarenal Doppler ultrasonography showed a monophasic IRVF pattern indicating a severely elevated interstitial renal pressure. After aggressive decongestion, a dynamic behaviour was found in IRVF changing from monophasic to biphasic pattern in parallel with an improvement in clinical parameters and renal function (serum creatinine changed from 1.81 to 1.44 mg/dL). In this case of a patient with AHF and WRF, IRVF changed after aggressive decongestion in agreement with clinical evolution. According to these findings, this technique could provide valuable information for identifying patients with a 'congestion kidney failure' phenotype. Further studies are needed confirming this observation and evaluating the potential role of this technique for guiding decongestive therapy in patients with AHF and WRF.