THE ASSOCIATION BETWEEN PREOPERATIVE AND POSTOPERATIVE HEPATIC VENOUS FLOW AND THE OUTCOME AFTER CARDIAC SURGERY

Introduction The hepatic venous flow reflects the pressure changes of the right ventricle. (1) Therefore, it starts to appear as a part of the echocardiographic examinations. Moreover, the back-and-forth link between the cardiovascular state and the liver is well-known for several years. (2,3) Our objective was to evaluate the association between preoperative and postoperative hepatic venous flow and the outcome of patients who underwent cardiac surgery. Methods Our prospective, observational study included 30 patients who underwent cardiac surgery between 2021 January and June at our Heart and Vascular Centre. Beside the routine echocardiographic examination, we also measured the venous blood flow in the common hepatic vein before the influx into the Inferior Vena Cava with Doppler ultrasound before and after the surgical procedure. We recorded the standard four waves’ (V, D, S, A) maximal speed and velocity time integral (VTI). In our database we recorded the patients’ demographic data, preoperative and postoperative hemodynamic and hepatobiliar markers and the EuroSCORE. We collected the length of stay (LOS), the intensive care unit stay, the vasopressor and inotrope need, and the occurrence of acute kidney injury (AKI). Our primary outcome was AKI, it was defined by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines, which is one of the first signs of circulation problems. We used the SPSS 22 program to analyse our data, with descriptive parameters and Cox-regression analyses. Results Median age was 67.9 (IQR 25-75: 60.6-73.6), none of them had any liver or renal disease in their medical history. Most common surgical procedure was AVR (atrial valve repair) (40%). During the first postoperative week 6 patients developed AKI. Between the AKI and non-AKI subgroups with Inverse Probability Weighting we found a significant difference at the postoperative A and D waves’ VTI, (p=0,031 and 0,022) and the preoperative retrograde/anterograde waves’ VTI ratio after adjustment for age, Euroscore, diabetes and GFR. (p=0,001). With paired-samples T test the V waves’ VTI's difference was significant between the preoperative and postoperative measurement. Discussion The increment in the hepatic venous retrograde waves, which are related to hepatic stasis, can predict worse outcomes among cardiac patients. Therefore, we might include this potentially useful tool in routine echocardiographic examinations and monitoring through the whole hospital stay.