A 78-year-old man presents to the emergency department for evaluation of sudden onset squeezing chest pain with radiation to the left shoulder. He has felt this way before on several occasions, but the sensation has never persisted more than 30 seconds. Past medical history is significant for hypertension. Physical examination reveals diaphoresis and tachycardia, and an electrocardiogram is significant for ST elevations in leads I, aVL, V5 and V6. Percutaneous coronary intervention is not available, and the next closest hospital is three hours away.
Which of the following agents is the most appropriate next step in this patient’s care?
A) Alteplase
This patient is presenting with an acute ST-segment myocardial infarction (STEMI), most likely a lateral infarction. Ideally, he would be treated with percutaneous coronary intervention (PCI) within 90 minutes of first hospital contact, or 120 minutes if transferred to an alternate facility. Because neither of thoee options is possible, he should receive a fibrinolytic agent such as alteplase.
Answer choice B: Bivalirudin, is incorrect. Bivalirudin is a direct thrombin inhibitor. It is preferred to heparin for pre-PCI anticoagulation in patients who have a history of heparin-induced immune thrombocytopenia.
Answer choice C: Enoxaparin, is incorrect. Enoxaparin is a low molecular weight heparin (LMWH) with mostly anti-Xa effects. It is used for treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE) as well as for postoperative DVT prophylaxis. It has a longer duration of action and more complex dosing than unfractionated heparin (UFH), and for this reason is not the preferred pre-PCI anticoagulation agent.
Answer choice D: Fondaparinux, is incorrect. Fondaparinux is a synthetic derivative of LMWH with anti-Xa activity. It is not preferred for pre-PCI anticoagulation because some data indicates increased risk of catheter thrombi and adverse coronary artery events compared to UFH.
Answer choice E: Unfractionated heparin, is incorrect. Unfractionated heparin is the preferred anticoagulation agent for patients prior to PCI. It is easier to monitor and requires a shorter duration of infusion compared to bivalirudin.
Key Learning Point
Primary percutaneous coronary intervention is the preferred reperfusion strategy for patients with acute ST-segment elevation myocardial infarction. When this cannot be performed within 90 minutes of first hospital contact, patients without contraindications should receive fibrinolytic therapy such as alteplase.
