A client with a history of unstable angina presents to the emergency department with constant chest pressure that is unrelieved with rest. The client appears anxious, pale, and diaphoretic. After obtaining the client's vital signs, which action should the nurse take next?

A. Administer four 81 mg aspirin tablets providing instructions to chew before swallowing: Aspirin helps inhibit platelet aggregation and is commonly administered to clients with suspected acute coronary syndrome to reduce the risk of myocardial infarction. B. Evaluate upper and lower extremities for perfusion, pulse volume, and pitting edema: While assessing extremities is important, administering aspirin takes priority in clients with suspected acute coronary syndrome. C. Place an indwelling urinary catheter and institute strict intake and output measurements: This intervention is not indicated in the immediate management of a client with suspected acute coronary syndrome. D. Secure client consent for coronary angiography and percutaneous coronary intervention: While these procedures may be necessary later, the immediate priority is to administer aspirin and stabilize the client's condition.