Perioperative Doppler ultrasound assessment of portal vein flow pulsatility in high-risk cardiac surgery patients: a multicentre prospective cohort study

Background: Portal vein Doppler ultrasound pulsatility measured by transoesophageal echocardiography is a marker of the haemodynamic impact of venous congestion in cardiac surgery. We investigated whether the presence of abnormal portal vein flow pulsatility is associated with a longer duration of invasive life support and postoperative complications in high-risk patients. Methods: In this multicentre cohort study, pulsed-wave Doppler ultrasound assessments of portal vein flow were per-formed during anaesthesia before initiation of cardiopulmonary bypass (before CPB) and after separation of cardiopul-monary bypass (after CPB). Abnormal pulsatility was defined as portal pulsatility fraction (PPF) >= 50% (PPF50). The primary outcome was the cumulative time in perioperative organ dysfunction (TPOD) requiring invasive life support during 28 days. Secondary outcomes included major postoperative complications.Results: 373 patients, 71 (22.0%) had PPF50 before CPB and 77 (24.9%) after CPB. PPF50 was associated with longer duration of TPOD (median [inter-quartile range]; before CPB: 27 h [11-72] vs 19 h [8.5-42], P=0.02; after CPB: 27 h [11-61] vs 20 h[8-42], P=0.006). After adjusting for confounders, PPF50 before CPB showed significant association with TPOD. PPF50 after CPB was associated with a higher rate of major postoperative complications (36.4% vs 20.3%, P=0.006).Conclusions: Abnormal portal vein flow pulsatility before cardiopulmonary bypass was associated with longer duration of life support therapy after cardiac surgery in high-risk patients. Abnormal portal vein flow pulsatility after cardio-pulmonary bypass separation was associated with a higher risk of major postoperative complications although this association was not independent of other factors.Clinical trial registration: NCT03656263.