Case Presentation: A 46-year-old white male with a history of prior MI (at age 37) presented to ED with left-sided weakness, facial droop, and decreased left-arm sensation. He did not have a history of obesity, hypertension, smoking, excess alcohol consumption, or hyperlipidemia but had a family history of a sister who had a stroke in her 30s. With NIHSS score of 12 and last known normal time forty-five minutes before arrival, stroke alert was called. tPA was given after ruling out an acute intracerebral bleed on the CT head without contrast. CTA head showed a right M1 occlusion. Thus, TICI 3 revascularization was performed. Transthoracic echocardiogram showed a 48% ejection fraction without structural heart disease or septal defect. Patient received Atorvastatin 40 mg and aspirin 325 mg. Hypercoagulability panel included testing for Factor V Leiden (FVL), prothrombin gene mutation, and anti-cardiolipin and B2 glycoprotein antibodies were ordered. The patient’s symptoms rapidly improved and upon discharge he had complete return of muscle strength and no neurologic deficits. He was later found to have heterozygous FVL mutation and was referred to a hematologist to discuss further management.
Discussion: FVL is a mutation that blunts the coagulation cascade’s ability to self-regulate thrombin activation, leading to a seven-fold and 20-80 fold greater risk for venous thrombosis in heterozygous and homozygous patients, respectively.3 Additionally, within the population with a TE, the mutation prevalence is 10-20%.3 The relationship between FVL and arterial thrombosis such as acute ischemic stroke remains controversial.1 Our patient had suffered two arterial thrombotic events at a relatively young age and lacked additional risk factors. Therefore, the decision to test for hypercoagulability was made. Anticoagulation therapy and recent TE disease affect results of thrombophilia testing. Heparin interacts with antithrombin, prevents protein C and S activation, and increases coagulation parameters. It causes inaccurate laboratory measurements of these proteins and distorting assays of lupus anticoagulant.4 During the acute phase of thrombosis, consumption of protein C, protein S, and antithrombin occurs, leading to unreliable measurements.2, 5 Tests for Factor V Leiden, prothrombin gene mutation, anticardiolipin antibodies, and anti B2 glycoprotein antibodies are not affected by anticoagulants or the acute phase of thrombosis. Heterozygous FVL patients may have a higher risk of arterial thrombosis than homozygous mutations.6 Data regarding treatment is sparse, but published cases have been treated with antiplatelet therapy and high-intensity statins.7
Conclusions: For patients who experience unprovoked TE and TE events at a young age, conscientious inpatient thrombophilia testing reduces cost burden and increases the accuracy of diagnosis. Heterozygous FVL mutation may have more arterial thrombosis risk than homozygous mutation.