Disorders of coagulation challenge normal hemostasis, increasing the risk of bleeding complications and the need for transfusion of blood products. Thrombotic coagulation disorders can be associated with increased risk of perioperative arterial and venous thromboembolic events.
Bleeding disorders can be categorized by disorders of platelets and the coagulation system proteins including clotting factors. Mild disorders often do not require hemostatic intervention to allow for surgery. More severe bleeding disorders can typically be treated with medications, factor concentrates, and transfusions to allow for surgery to be successfully completed.
Thrombotic disorders can be inherited or acquired. This chapter will review inherited thrombophilias and the antiphospholipid antibody syndrome. Other acquired thrombophilic conditions, including liver disease, malignancy, kidney disease, and rheumatic diseases, are reviewed in other chapters. Perioperative management of antiplatelet and anticoagulants are also covered elsewhere within this textbook. See Chapters 4, 5, and 10.
All patients undergoing planned surgical treatment warrant preoperative evaluation for a bleeding disorder. Despite advances in ease and reliability of blood counts, coagulation studies, and thrombophilia tests, an accurate history and physical examination remain the most-effective screening tools for bleeding and clotting disorders. Multiple meta-analyses have demonstrated routine use of coagulation “screening” tests in asymptomatic patients leads to inappropriate delay of procedures and unnecessary concern for patients with abnormal results.1 Instead, a focused history should evaluate for personal or family history of bleeding and clotting symptoms, previous procedural complications, obstetric/gynecologic history, and medications. Physical examination findings that may suggest an underlying bleeding disorder and warrant further evaluation include petechiae, ecchymosis, joint hypermobility, hemarthropathy, telangiectasias, joint hypermobility, jaundice, and other stigmata of liver disease.
If history or physical exam is suggestive of a possible bleeding disorder, laboratory evaluation is warranted. Initial laboratory evaluation should include a complete blood count (CBC), prothrombin time (PT), and partial thromboplastin time (PTT). Additional diagnostic testing including liver and kidney function, peripheral blood smear, coagulation factors (factor VIII, IX, XI, fibrinogen, and von Willebrand factors [vWF]), and platelet function assays should be performed based on both clinical suspicion of possible bleeding disorder and screening labs. Table 22-1 reviews causes of prolongation of PT and PTT, and Figure 22-1 includes algorithms on the diagnostic approach to evaluation of the patient with an abnormal PT/INR and/or PTT. Table 22-2 reviews common causes of thrombocytopenia. If diagnosis is uncertain, preperative evaluation by a hematologist is appropriate to establish a diagnosis and determine an appropriate treatment plan. Regular use of whole blood and point of care assays including bleeding time (BT), platelet function analyzer (PFA-100), and thromboelastography (TEG) have not been reliable at predicting perioperative bleeding.
Diagnostic approach to the patient with an abnormal PT/INR and/or PTT. (Reproduced with permission from Pfeifer K. www.preopevalguide.com).