Section 4: Ischemic Emergencies – Stroke (CVA) & STEMI Care

In the landscape of emergency medicine, no phrase is more potent or universally understood than “Time is Tissue.” This principle is the absolute bedrock of care for ischemic emergencies, namely Acute Ischemic Stroke (AIS) and ST-Elevation Myocardial Infarction (STEMI). It encapsulates a brutal reality: for every minute that blood flow is obstructed to the brain or the heart, a quantifiable and often irreversible amount of tissue dies. The mission for the entire healthcare team—and especially for the pharmacist handling the critical thrombolytic agent—is a race against this inexorable clock. Understanding the profound implications of this principle is what separates a technician from a clinical practitioner. It is the “why” that drives the urgency, the meticulousness, and the focus required in these high-stakes scenarios.

Deep Dive: The Ischemic Cascade

The pathophysiology is elegantly simple and devastatingly effective. In an ischemic stroke, a thrombus (blood clot) lodges in a cerebral artery, cutting off the supply of oxygen and glucose. In a STEMI, a ruptured atherosclerotic plaque in a coronary artery triggers thrombus formation, occluding the vessel. In both cases, a core of tissue at the center of the ischemic zone dies within minutes. Surrounding this core is a region of stunned, dysfunctional but still viable tissue known as the penumbra (in the brain) or stunned myocardium (in the heart). This is the tissue that can be saved. The entire goal of hyperacute therapy is to restore blood flow—to achieve reperfusion—as rapidly as possible to salvage this threatened tissue. The longer the vessel remains occluded, the larger the core of dead tissue grows, consuming the salvageable penumbra until the damage is complete and permanent.

When a “Code Stroke” or “Code STEMI” is activated, the pharmacist becomes the single most important safety checkpoint in the medication use process. The therapeutic agents, alteplase (tPA) and the increasingly common tenecteplase (TNK), are among the highest-risk medications in the hospital. They are powerful enzymes that dissolve fibrin clots, but their action is not specific. They cannot distinguish between the pathologic clot causing the ischemia and the physiologic clots that prevent bleeding. Administered correctly, they can reverse paralysis or stop a heart attack. Administered incorrectly, or to the wrong patient, they can cause a fatal intracranial hemorrhage. Your role is to be the methodical, independent, and final guardian at the gate.

The Thrombolytic Safety Checklist: Your Non-Negotiable Workflow

Before any thrombolytic is administered, a rigorous safety checklist must be completed. This is not a passive confirmation; it is an independent verification. You must be confident enough to be the person who says “STOP” if you find a critical contraindication.

4.2.2 Zero-Error Dosing: Alteplase vs. Tenecteplase

This is a critical evolution in stroke care. For years, alteplase was the only option. Now, tenecteplase is rapidly becoming the preferred agent at many institutions. You must be an expert in both.

4.3 Post-Thrombolytic Management: The Vigilance Period

The 24 hours following thrombolysis is a period of heightened risk. Your role shifts from emergency response to one of vigilant monitoring, proactive risk mitigation, and expert consultation.

• Blood Pressure Control: The #1 Priority. Hypertension is the single most important modifiable risk factor for hemorrhagic conversion. The goal is to maintain blood pressure at or below 180/105 mmHg for at least 24 hours. Your role is to ensure the appropriate IV agents (Labetalol, Nicardipine) are readily available and dosed correctly.
• The 24-Hour “No-Fly Zone.” For 24 hours post-thrombolytic, all other anticoagulant and antiplatelet medications are strictly contraindicated. Your most important job is to perform a meticulous medication reconciliation and proactively place all scheduled home antithrombotics on hold. A follow-up head CT is required 24 hours later to rule out hemorrhage before any of these agents can be safely restarted.