Stroke Anticoagulation

Stroke is one of the leading causes of death and long-term disability worldwide.[1][2] As medical management advances, the incidence and mortality rate of stroke declines, with the majority of strokes presenting as ischemic strokes vs. hemorrhagic strokes. As such, the focus of this article will be on ischemic strokes. Various etiologies lead to ischemic stroke, including both modifiable and non-modifiable risk factors. Non-modifiable risks include age, sex, and race/ethnicity.[3] Whereas, modifiable risk factors encompass: physical inactivity, waist-to-hip ratio, alcohol consumption, smoking, nutrition, hypertension, hyperlipidemia, diabetes mellitus, cardiac causes, such as atrial fibrillation (AF), and metabolic syndromes.[3][4][5] Moreover, short term triggers may also pose a risk for stroke, including acute infectious process, and stress, etc. Assessing a patient’s risk for stroke based on risk factors is an important component of primary care for strokes. There are several validated risk stratification calculators used to assist in identifying patients needing preventative therapies. For instance, a recognized, continuously updated tool to predict clinical stroke is the Framingham Stroke Risk Profile, which combines both modifiable and non-modifiable risks.[3][6] Ultimately, targeted interventions can decrease the burden of stroke. Stroke rule out should be completed in patients presenting with altered consciousness or sudden, focal, or global neurological deficits. Time is of the essence in completing a thorough history and physical in patients presenting with stroke-like symptoms. Upon presentation, one of the most crucial steps is to identify the time of ischemic stroke symptoms onset, as that helps to determine eligibility for antithrombotic treatment or endovascular intervention. The goals of physical examination are to determine stroke location, distinguish stroke mimics, complete neurological deficit assessment, and identify comorbidities and conditions that can affect treatment. A clinician should complete a neurological assessment should be completed, and baseline function calculated via the National Institutes of Health Stroke Scale (NIHSS). The history and physical examination should be used to rule out other mimics of stroke, including hyperglycemia, hypoglycemia, seizures, syncope, migraines, or drug toxicity, etc. A focused history should identify ischemic stroke risk factors discussed earlier in this article and should also identify any recent trauma, coagulopathies, use of oral contraceptives, illicit drug use, such as cocaine, and migraines. The following merit consideration when starting therapy: non-contrast brain CT or MRI, blood glucose, and oxygen saturation. In addition, all patients should also have baseline labs that include: complete blood count with platelet count, serum electrolytes/renal function, cardiac panel, activated partial thromboplastin time (APTT), prothrombin time/INR, and ECG; although it is desirable to know the results of the preceding labs, therapy should not be delayed while results are pending, the exception being if there is suspicion for thrombocytopenia or bleeding abnormalities, and use of heparin or warfarin or other anticoagulants. In patients with suspected stroke, an emergent non-contrast computed tomography (CT) is generally the first step in the diagnostic study to rule out any bleeding. The results of the CT will also help determine if the patient is a candidate for antithrombotic therapy. MRI testing may also be used to identify intracerebral hemorrhaging and is more sensitive than CT for early detection of brain infarction. The essential lab before initiation of therapy is blood glucose, as hypoglycemia or hyperglycemia can mimic stroke.[7][8][9][10] A vitals assessment with a focus on respiration, temperature, and blood pressure should also be obtained upon presentation. Elevation in blood pressure could be indicative of the body’s response to maintain brain perfusion to occluded section. Patients with hypoventilation can result in an increase in carbon dioxide partial pressure, which can further cause cerebral vasodilation and elevation in intracranial pressure (ICP), at which point there shoudl be assessment of the need for intubation. Finally, normothermia is important for the first few days post-acute stroke, as fever can worsen ischemia. [7], [10] There are significant updates to literature that have come to surface for effective and appropriate management of patients with ischemic stroke. Also, the American Heart Association/American Stroke Association (AHA/ASA) has published guidelines, most recent being in 2018, outlining optimal treatment for the early management of patients with ischemic stroke. Ischemic stroke intervention includes the use of thrombolytic, anticoagulants, antiplatelet, statins, antihypertensive, and blood glucose management.[11] Previously, anticoagulation played a significant role in the acute treatment of ischemic stroke. Recent studies have helped refine their use and have restricted the start time of anticoagulation post-ischemic stroke to only certain patient populations. Anticoagulants now play a major role in primary and secondary prevention of ischemic strokes.