Thrombolysis is an emergency medical intervention for stroke. It dissolves blood clots obstructing blood flow to the brain, restoring circulation. This treatment is time-sensitive; its effectiveness depends on quick administration after stroke symptoms begin. The objective is to mitigate brain damage and improve outcomes for individuals experiencing ischemic stroke.
Understanding Ischemic Stroke
An ischemic stroke occurs when a blood clot blocks an artery supplying blood to the brain. This blockage prevents oxygen and nutrients from reaching brain tissue, causing brain cells to die quickly. It is the most common type of stroke, accounting for about 87% of all stroke cases.
This differs from a hemorrhagic stroke, where a blood vessel in the brain leaks or ruptures, leading to bleeding within or around the brain. While both are medical emergencies, their treatments vary significantly, and administering clot-dissolving drugs in a hemorrhagic stroke can worsen the outcome. The concept of “time is brain” emphasizes the rapid loss of brain cells during an ischemic stroke. Prompt medical intervention is vital to preserving brain function and minimizing long-term disability.
Thrombolysis: The Clot-Busting Treatment
Thrombolysis uses medications to dissolve blood clots. The primary medication used is recombinant tissue plasminogen activator, often referred to as rtPA or alteplase. This medication works by targeting fibrin, a protein that forms the mesh-like structure within blood clots.
Once alteplase binds to the fibrin within a clot, it activates plasminogen, converting it into active plasmin. Plasmin then breaks down the fibrin molecules, dissolving the blood clot. This process restores blood flow, minimizing brain damage and improving neurological outcomes.
When and For Whom is Thrombolysis Used?
Thrombolytic drugs for ischemic stroke are governed by strict criteria and a narrow time window. For alteplase, treatment is recommended within 4.5 hours of stroke symptom onset. The earlier treatment begins, the greater the potential benefit, with efficacy diminishing over time.
Eligibility for thrombolysis depends on several factors, including the patient’s age, stroke severity, and medical history. Patients are generally excluded if they have:
- Active internal bleeding
- Recent severe head trauma
- Intracranial surgery within the past three months
- A history of intracranial hemorrhage
- Uncontrolled high blood pressure
- Recent major surgery
- Bleeding disorders
- Current use of blood-thinning medications
A rapid assessment, including a CT scan of the brain, is performed to rule out a hemorrhagic stroke before thrombolysis can be considered.
What to Expect During and After Thrombolysis
Thrombolytic medication, such as alteplase, is administered intravenously. During and immediately after the infusion, patients undergo continuous monitoring in a specialized unit. This includes frequent checks of vital signs, like blood pressure, and neurological status to detect changes or complications.
A significant potential side effect of thrombolysis is bleeding, with intracranial hemorrhage being the most serious concern. Medical teams carefully manage this risk by adhering to strict eligibility criteria and closely monitoring the patient. If severe headache, acute hypertension, nausea, vomiting, or worsening neurological symptoms occur, the infusion may be discontinued, and an emergency CT scan is performed. Following treatment, patients continue to be monitored for improvement or complications, and rehabilitation efforts often begin promptly to support recovery.