Ultrasound Hepatic Vein Ratios Are Associated With the Development of Acute Kidney Injury After Cardiac Surgery.

Objective: The authors investigated the use of hepatic venous and right-heart ultrasound parameters in predicting cardiac surgery-associated acute kidney injury (AKI).

Design: This was a prospective, contextual, descriptive two-center study. Blood tests,clinical and ultrasound data were obtained preoperatively, and postoperative day one, and day four. The hepatic vein, inferior vena cava, and right-heart Doppler ultrasound parameters were obtained and analyzed.

Setting: The sites of the study were Johannesburg, South Africa, and Aarhus, Denmark.

Participants: Adult patients who satisfied inclusion criteria, between August 2019 and January 2020, were included, with a total of 152 participants.

Interventions: None.

Measurements And Main Results: The median (interquartile range) age of patients was 68 (55-73) years, predominantly male, and the majority were hypertensive. Of 152 patients analyzed, 54 (35%) patients developed AKI. Among these, 37 (69%) were classified as Kidney Disease: Improving Global Outcomes (KDIGO) stage I, 11 (20%) as stage II, while six (11%) were stage III. Age (adjusted odds ratio [AOR] 1.05, 95% confidence interval [CI] 1.00-1.10 p = 0.031), The European System for Cardiac Operative Risk Evaluation (EuroSCORE) II (AOR 1.43, 95% CI 1.14-1.80, p = 0.005], and preoperative serum creatinine (AOR 1.04, 95% CI 1.01-1.08, p = 0.013) were predictive of AKI. Those who developed AKI had experienced longer cardiopulmonary bypass (CPB) times (p < 0.001). Preoperatively, hepatic vein S-wave measurements were significantly higher in patients with AKI (p < 0.05). On postoperative day one (D1), the hepatic vein flow ratios of patients with AKI were significantly decreased, driven by low S waves and high D waves, and accompanied by significantly elevated central venous pressure (CVP) levels. CVP levels on D1 postoperatively were predictive of AKI (AOR 1.31, 95% CI 1.11-1.55, p = 0.001). Measurements of right ventricular (RV) base, tricuspid annular plane excursion (TAPSE), and inferior vena cava were not associated with the development of AKI (p > 0.05).

Conclusion: There was an association between the development of AKI and a decrease in hepatic flow ratios on D1, driven by low S-wave and high D-wave velocities. The presence of venous congestion was reflected by significantly elevated CVP values, which were independently associated with AKI on D1. RV base and TAPSE measurements were, however, not associated with AKI. These parameters may reflect perioperative circumstances, including prolonged CPB times and potential fluid management, which can be modified in this period.