DOPPLER ULTRASOUND ASSESSMENT OF INTRA-RENAL VENOUS FLOW IN PATIENTS WITH ACUTE DECOMPENSATE HEART FAILURE: A POTENTIAL ACUTE CARDIORENAL SYNDROME BIOMARKER

Abstract

Acute cardio-renal syndrome type 1 (CRS1) is common and associated with increased risk of adverse outcomes among patients with acute decompensated heart failure (ADHF). Intrarenal Doppler ultrasound of venous blood flow (IRD) is a novel biomarker reflecting severity of renal congestion that has previously demonstrated prognostic significance in ADHF. This prospective pilot study assessed the association between IRD and acute kidney injury (AKI) among inpatients with ADHF. Additionally, IRD patterns between ADHF and ACS inpatients without ADHF were compared. Consenting adult ADHF inpatients with ongoing congestion and ACS inpatients stable post-catheterization were prospectively enrolled. All patients underwent complete TTE. IRD was performed by a single operator with a standard TTE machine (iE33, Philips Medical Systems). IRD was qualitatively graded as continuous (normal) or discontinuous (abnormal). IRD was also quantified through a novel measure, the venous flow duration (VFD), defined as venous flow duration per cardiac cycle divided by total cardiac cycle duration. Cardiac output (VTI method) and CVP (IVC method) were estimated by TTE. Charts were reviewed for clinical and laboratory data. AKI was defined by KDIGO criteria. Proportions were compared with Fisher’s exact test, means with T-test, with alpha of < 0.05. This study was approved by ethics and hospital administration. 21 patients have been enrolled (ADHF=12; ACS=9). Compared to ACS, ADHF patients had higher heart rate and estimated CVP but similar cardiac index and baseline renal function. IRD was discontinuous in 100% (12/12) ADHF and 0% (0/9) ACS patients (P=0.000013). VFD was 0.419 versus 1.00 in ADHF and ACS patients, respectively (P < 0.00001). Stage II/III AKI occurred in 42% (5/12) ADHF versus 0% (0/9) ACS patients (P=0.045). Among ADHF patients there was a trend towards higher VFD in those without AKI (3/12) versus those with AKI (9/12) (0.527 versus 0.382, P=0.098). Serial IRD over three days in a single ADHF patient improved from discontinuous to continuous after therapy with intravenous loop diuretics, which paralleled clinical improvement. This prospective pilot study showed that assessment of IRD is feasible and correlates with clinical congestion among ADHF inpatients. All ADHF patients had abnormal IRD, including ADHF patients without AKI as defined by serum creatinine criteria, whereas ACS patients had normal IRD. Abnormal IRD may reflect vulnerability to CRS1. Data collection is ongoing and will clarify these preliminary findings. Further study to determine the association between IRD and CRS1 is warranted, potentially through comparison with novel biomarkers of renal function such as Cystatin C.View Large Image Figure ViewerDownload Hi-res image Download (PPT)