Impact of cardiopulmonary bypass and surgical complexity on plasma soluble urokinase-type plasminogen activator receptor levels after cardiac surgery.

BACKGROUND: Circulating soluble urokinase plasminogen activator receptor (suPAR) is a marker of inflammation with prognostic value for elevated risk of morbidity and mortality. It has not yet been shown how the inflammatory process induced by cardiac surgery affects suPAR concentrations postoperatively. METHODS: In a prospective observational study, plasma suPAR levels were measured in 30 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB), pre-, peri, post-operatively, and 3-5 days after surgery. Fifteen patients underwent coronary artery bypass grafting (CABG) and 15 underwent complex procedures with longer CPB duration. Concentrations of suPAR at each time point were compared to the preoperative levels and compared between the two groups. RESULTS: In both groups, plasma suPAR concentrations were significantly higher on the first postoperative day (3.27 (interquartile range (IQR) 2.75-3.86) µg/L compared to baseline (2.62 (1.98-3.86)) µg/L, p < .001. There were no significant differences in suPAR concentrations between the groups at any time point. Preoperatively, the median suPAR concentration was 2.57 (2.01-3.60) µg/L in the CABG group versus 2.67 (1.89-3.97) µg/L in the complex group (p = .567). At ICU arrival 2.48 (2.34-3.23) µg/L versus 2.73 (2.28-3.44) µg/L in CABG and complex patients, respectively (p = .914). There was no difference in suPAR concentrations between the groups on postoperative day 1 (3.34 (2.89-3.89) versus 3.19 (2.57-3.62) p = .967) or 3-5 days after surgery (2.72 (1.98-3.16) versus 2.96 (2.39-4.28) p = .085. CONCLUSIONS: After a transient rise on the first postoperative day, the suPAR levels returned to the preoperative levels by the third postoperative day. There was no significant difference in suPAR levels between the routine CABG and complex group with longer CPB time.

The Dynamics of Heparin-Binding Protein in Cardiothoracic Surgery-A Pilot Study.

OBJECTIVES: To explore the preoperative, intraoperative, and postoperative dynamics of heparin-binding protein (HBP) in cardiothoracic surgery. DESIGN: This was a prospective, observational study. SETTING: The study was conducted at a single university hospital. PARTICIPANTS: Thirty patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) were included, 15 of whom underwent coronary artery bypass grafting surgery and 15 of whom underwent complex procedures. Ten patients undergoing lung surgery also were included as a conventional surgery reference group. INTERVENTIONS: No interventions were performed. MEASUREMENTS AND MAIN RESULTS: HBP was measured at nine different perioperative times. HBP levels increased immediately after heparin administration, further increased during CPB, but decreased rapidly after protamine administration. At arrival to the intensive care unit, median HBP levels were 24.8 (15.6-38.1) ng/mL for coronary artery bypass grafting patients and 51.2 (34.0-117.7) ng/mL for complex surgery patients (p = 0.011). One day after surgery, HBP levels in all three groups were below the proposed cutoff of 30 ng/mL, which previously was found to predict development of organ dysfunction in patients with infection. CONCLUSIONS: HBP levels are elevated by the administration of heparin and the use of CPB but reduced by protamine administration. At postoperative day one, HBP levels were less than the threshold for organ dysfunction in patients with infection. The usefulness of HBP for predicting postoperative infections in cardiothoracic surgery should be investigated in future studies.

Utility of heparin-binding protein following cardiothoracic surgery using cardiopulmonary bypass.

Cardiothoracic surgery using cardiopulmonary bypass (CPB) triggers an inflammatory state that may be difficult to differentiate from infection. Heparin-binding protein (HBP) is a candidate biomarker for sepsis. As data indicates that HBP normalizes rapidly after cardiothoracic surgery, it may be a suitable early marker of postoperative infection. We therefore aimed to investigate which variables influence postoperative HBP levels and whether elevated HBP concentration is associated with poor surgical outcome. This exploratory, prospective, observational study enrolled 1475 patients undergoing cardiothoracic surgery using CPB, where HBP was measured at ICU arrival. Patients with HBP in the highest tercile were compared to remaining patients. Multivariable logistic regressions were performed to identify factors predictive of elevated HBP and 30-day mortality. Overall median HBP was 30.0 ng/mL. Patients undergoing isolated CABG or surgery with CPB-duration ≤ 60 min had a median HBP of 24.9 ng/mL and 23.2 ng/mL, respectively. Independent predictors of elevated postoperative HBP included increased EuroSCORE, prolonged CPB-duration and high intraoperative temperature. Increased HBP was an independent predictor of 30-day mortality. This study confirms the promising characteristics of HBP as a biomarker for identification of postoperative sepsis, especially after routine procedures. Further studies are required to investigate whether HBP may detect postoperative infections.