What are the coagulation panel results for a patient with Cerebrovascular Accident (CVA)?

From the Guidelines

A coagulation panel for a cerebrovascular accident (CVA) or stroke should include prothrombin time (PT) with international normalized ratio (INR), activated partial thromboplastin time (aPTT), complete blood count with platelets, and fibrinogen levels. These tests help determine if the stroke is ischemic or hemorrhagic and guide treatment decisions, as noted in the 2020 ACC expert consensus decision pathway on management of bleeding in patients on oral anticoagulants 1. For patients with ischemic stroke who are candidates for thrombolytic therapy with tissue plasminogen activator (tPA), these tests must be obtained urgently as tPA should be administered within 4.5 hours of symptom onset.

The importance of coagulation testing in CVA is further emphasized by the 2021 ACC expert consensus decision pathway for anticoagulant and antiplatelet therapy in patients with atrial fibrillation or venous thromboembolism undergoing percutaneous coronary intervention or with atherosclerotic cardiovascular disease 1. This pathway highlights the complexity of cerebrovascular disease and the need for tailored antithrombotic therapy based on the type of cerebrovascular disease, prior symptomatic events, prior interventions, and perceived bleeding risk.

Key components of the coagulation panel include:

• Prothrombin time (PT) with international normalized ratio (INR) to assess the extrinsic coagulation pathway
• Activated partial thromboplastin time (aPTT) to assess the intrinsic coagulation pathway
• Complete blood count with platelets to evaluate for thrombocytopenia or other hematologic abnormalities
• Fibrinogen levels to assess for hypofibrinogenemia or hyperfibrinogenemia

Additional specialized tests may be included, such as:

• D-dimer to assess for hypercoagulable states
• Protein C and S levels, antithrombin III, factor V Leiden, and antiphospholipid antibodies, particularly in younger patients or those with recurrent strokes without obvious risk factors. These tests help identify underlying coagulation disorders that may have contributed to the stroke and inform secondary prevention strategies, as discussed in the context of anticoagulant and antiplatelet therapy 1.

From the Research

Coagulate Panel for CVA

The coagulate panel, also known as coagulation panel, is a series of tests used to evaluate the coagulation pathway and detect any abnormalities that may lead to bleeding or clotting disorders.

• The panel typically includes prothrombin time (PT), activated partial thromboplastin time (APTT), and international normalized ratio (INR) 2, 3, 4.
• These tests are used to monitor warfarin and heparin therapy, evaluate for vitamin K deficiency, and assess hemostatic function in the setting of bleeding 3.
• The utility of coagulation testing in chest pain evaluation, routine perioperative assessment, prior to initiation of anticoagulation, and as screening for admitted patients is low, with little to no change in patient management based on results of these panels 3.
• Coagulation testing should be considered in systemically ill patients, those with a prior history of bleeding or family history of bleeding, patients on anticoagulation, or patients with active hemorrhage and signs of bleeding 3.

Interpretation of Coagulation Tests

• The interpretation of coagulation tests, such as PT, APTT, and INR, requires careful consideration of the clinical context and the potential effects of various factors, including anticoagulant therapy and laboratory variability 2, 4.
• Abnormal results from these tests may pose a diagnostic dilemma, and a practical approach to evaluation and reflexive testing is necessary to determine the underlying cause of the abnormality 4.
• The effect of dabigatran, a direct thrombin inhibitor, on coagulation assays, including INR, APTT, thrombin time, and fibrinogen, has been studied, and the results indicate that these assays may not be reliable for assessing the amount of dabigatran present 5.

Clinical Applications

• Coagulation panels are commonly ordered in the emergency department setting, but their utility is limited in certain clinical conditions, such as chest pain evaluation and routine perioperative assessment 3.
• Thromboelastography and rotational thromboelastometry offer more reliable measures of coagulation function and may be considered in patients with hemorrhage, patients on anticoagulation, and those with a personal or family history of bleeding 3.
• The diagnosis of coagulation disorders, such as von Willebrand disease, requires a combination of clinical assessment, laboratory testing, and specific assays, such as factor VIII and von Willebrand factor antigen 6.