Fibrinolysis and the Influence of Tranexamic Acid Dosing in Cardiac Surgery.

OBJECTIVE: The present study aimed to determine whether underlying disease, performed surgery, and dose of tranexamic acid influence fibrinolysis measured with D-dimer levels. DESIGN: Retrospective analysis. SETTING: Single institution (Department of Cardiac Surgery and Section of Clinical Hemostaseology at the Düsseldorf University Hospital). PARTICIPANTS: The study comprised 3,152 adult patients undergoing elective cardiac surgery between February 2013 and October 2016. INTERVENTIONS: Two doses of tranexamic acid during surgery were administered. MEASUREMENTS AND MAIN RESULTS: D-dimer levels were analyzed at the start of surgery and before protamine administration. D-dimer levels at the start of surgery were compared according to disease. Intraoperative D-dimer development was analyzed according to the type of surgery and within 2 cohorts with different tranexamic acid doses. Interindividual variability was pronounced for D-dimer levels at the start of surgery, with significant differences among patients with coronary artery disease, valve disease, and aortic disease and patients undergoing heart transplantation compared with patients receiving a left ventricular assist device (p < 0.01). Aortic dissection, endocarditis, and extracorporeal life support were associated with higher D-dimer levels (p ≤ 0.01). With tranexamic acid at a fixed dose, intraoperative D-dimer levels decreased in on-pump and off-pump coronary bypass surgery, valve surgery, and left ventricular assist device surgery (p ≤ 0.02), but levels increased in aortic surgery and heart transplantations (p < 0.01). A decrease or increase in D-dimer levels during surgery was influenced significantly by a higher or lower tranexamic acid dose (p ≤ 0.01). CONCLUSIONS: D-dimer testing allows for the assessment of individual fibrinolytic activity in cardiac surgery, which is influenced by disease type, surgery type, and dose of tranexamic acid. The assessment of the fibrinolytic status may have the potential to facilitate dose-adjusted antifibrinolytic therapy in the future.

The Impact of Intraoperative Patient Blood Management on Quality Development in Cardiac Surgery.

OBJECTIVES: Patient blood management (PBM) is increasingly introduced into clinical practice. Minimizing effects on transfusion have been proven, but relevance for clinical outcome has been sparsely examined. In regard to this, the authors analyzed the impact of introducing intraoperative PBM to cardiac surgery. DESIGN: Retrospective case-control study. SETTING: Single center. PARTICIPANTS: A total of 3,170 patients who underwent either coronary artery bypass grafting, isolated aortic valve replacement, or a combined procedure at the authors' institution between January 1, 2007, and December 31, 2015. INTERVENTION: In 2013, an intraoperative PBM service was established offering therapy recommendations on the basis of real-time laboratory monitoring. Comparisons to conventional coagulation management were adjusted for optimization of general, surgical, and perioperative care standards by interrupted time-series analysis and risk-dependent confounding by propensity- score matching. MEASUREMENTS AND MAIN RESULTS: Primary study endpoints were in-hospital mortality and morbidity. Morbidity was defined as clinically relevant prolongation of hospital stay, which was related to accumulation of postoperative complications. Transfusion requirements, bleeding, and thromboembolic complications were not treated as primary endpoints, but were also explored. The recommendations on the basis of real-time laboratory monitoring were adopted by the operative team in 72% of patients. Intraoperative PBM was associated independently with a reduction of morbidity (8.3% v 6.3%, p = 0.034), whereas in-hospitalmortality (3.0% v 2.6%, p = 0.521) remained unaffected. The need for red blood cell transfusion decreased (71.1% v 65.0%, p < 0.001), as did bleeding complications requiring surgical re-exploration (3.5% v 1.8%, p = 0.004). At the same time, stroke increased by statistical trend (1.0% v 1.9%, p = 0.038; after correction for imbalanced type of surgical procedure p = 0.085). CONCLUSIONS: Real-time laboratory recommendations achieved a high acceptance rate early after initiation. Improvement of clinical outcome by intraoperative PBM adds to the optimized surgical care. However, the corridor between hemostatic optimization and thromboembolic risk may be narrow.