Abstract
Cardiac surgery with cardiopulmonary bypass determines a serious imbalance of the
hemostatic system. The clinical pattern is multifactorial, involving patient-related,
drug-related, and surgery-related factors. As a result, the patient is prone to both
hemorrhagic and thrombotic complications. To address the clinical management of a
bleeding patient after cardiac surgery, avoiding empirical administration of drugs
and blood derivates, it is mandatory to correctly identify the factor(s) responsible
for bleeding. Bleeding after cardiac operations can be ascribed to seven basic mechanisms:
residual heparin effect; reduced thrombin generation; fibrinogen deficiency; thrombocytopenia;
platelet dysfunction; hyperfibrinolysis; and surgical sources. These factors may interact
together, creating a complex coagulopathy. Point-of-care coagulation tests are useful
to orienteer the clinician in this complex scenario. Viscoelastic coagulation tests
find their greater usefulness in the diagnosis of the bleeding mechanism(s), whereas
platelet function tests appear more useful for the preoperative assessment of patients
under the effects of antiplatelet agents. Thromboembolic complications are the other
side of the coin, and their prevention is still a matter of debate. Consumption of
natural anticoagulants and endothelial disturbance are important mechanisms underlying
this condition. Strategies to limit antithrombin (AT) consumption or to correct low
postoperative levels of AT are still a matter of discussion.
Keywords
cardiac surgery - cardiopulmonary bypass - bleeding - transfusions - point-of-care
tests
