Background: Right ventricular failure after cardiac surgery is associated with morbidity and mortality. Right ventricular dysfunction results in hepatic venous congestion, which impacts the portal circulation. We aimed to determine whether an increased portal flow pulsatility fraction was associated with right ventricular dysfunction in cardiac surgery patients. We also aimed to describe the haemodynamic factors and postoperative complications associated with an increased portal pulsatility in this setting. Methods: We conducted a prospective single-centre cohort study, recruiting adults undergoing cardiac surgery. Portal flow was assessed before, during, and after surgery by Doppler ultrasound. A detailed haemodynamic and echocardiographic assessment was performed at the same time points. Results: A total of 115 patients were included. Both systolic and diastolic right ventricular dysfunction were associated with a higher portal pulsatility fraction (P¼0.008 and <0.001, respectively). A positive association was present between portal pulsatility fraction and measurements representative of venous pressure (central venous pressure, inferior vena cava diameter). A post-procedural portal pulsatility fraction !50% measured in the operating room was present in 21 (18.3%) patients and was associated with an increased risk of major complications (odds ratio¼5.83, confidence interval, 2.04e16.68, P¼0.001). The addition of portal flow assessment to a predictive model including EuroSCORE II and systolic right ventricular dysfunction improved prediction of postoperative complications. Conclusions: High portal flow pulsatility fraction is associated with right ventricular dysfunction, signs of venous congestion and decreased perfusion, and an increased risk of major complications. Portal vein Doppler ultrasound appears to be promising for risk assessment in the perioperative period. Clinical trials registration: NCT02658006.

Objectives: Postoperative pulmonary complications increase mortality, length, and cost of hospitalization. A better diaphragmatic strength may help face an increased work of breathing postoperatively. We, therefore, sought to determine if a low preoperative diaphragm thickening fraction (TFdi) determined by ultrasonography helped predict the occurrence of postoperative pulmonary complications after cardiac surgery independently of indicators of frailty, sarcopenia, and pulmonary function. Design: Prospective observational cohort study. Setting: Montreal Heart Institute, an academic cardiac surgery center in Canada. Patients: Adults undergoing nonemergency cardiac surgery. Interventions: We measured the preoperative thickness of the right and left hemidiaphragms at their zone of apposition at end-expiration (Tdi,ee) and peak-inspiration (Tdi,ei) with ultrasonography. Maximal thickening fraction of the diaphragm during inspiration (TFdi,max) was calculated using the following formula: TFdi,max = (Tdi,ei–Tdi,ee)/Tdi,ee. We also evaluated other potential risk factors including demographic parameters, comorbidities, Clinical Frailty Scale, grip strength, 5-meter walk test, and pulmonary function tests. We repeated TFdi,max measurements within 24 hours of extubation. The primary composite outcome of this study was the occurrence of postoperative pulmonary complications, defined as pneumonia, clinically significant atelectasis, or prolonged mechanical ventilation (> 24 hr). Measurement and Main Results: Of the 115 patients included, 34 (29.6%) developed postoperative pulmonary complications, including two with pneumonia, four with prolonged mechanical ventilation, and 32 with clinically significant atelectasis. Those with postoperative pulmonary complications had prolonged ICU and hospital length of stays. They had a lower TFdi,max (37% [interquartile range, 31–45%] vs 44% [interquartile range, 33–58%]; p = 0.03). In multiple logistic regression, a TFdi,max less than 38.1% was associated with postoperative pulmonary complications (odds ratio, 4.9; 95% CI, 1.81–13.50; p = 0.002). All patients who developed pneumonia or prolonged mechanical ventilation had a TFdi,max less than 38.1%. Respiratory rate and diabetes were also independently associated with postoperative pulmonary complications, while pulmonary function tests and the assessed indicators of frailty and sarcopenia were not. Conclusions: A low preoperative TFdi,max can help to identify patients at increased risk of postoperative pulmonary complications after cardiac surgery.