Tissue Plasminogen Activator (TPA) is a medication used in emergency settings to treat certain types of stroke. It functions as a clot-dissolving agent, clearing blockages in blood vessels. TPA’s primary purpose is to restore blood flow to the brain when interrupted by a clot. This time-sensitive treatment aims to limit brain damage and improve patient outcomes.
Understanding TPA and Its Action
TPA, or Tissue Plasminogen Activator, is a protein administered as alteplase to break down blood clots. It converts plasminogen into plasmin, an enzyme that dissolves fibrin, a key component of blood clots. By dissolving the clot, TPA reopens blocked blood vessels and restores blood flow to affected brain tissue.
When TPA is Administered for Stroke
TPA is primarily administered for ischemic stroke, caused by a blood clot blocking brain blood flow. It is not used for hemorrhagic stroke, a type caused by bleeding, as it would worsen the condition. Before administration, diagnostic tests like a CT scan rule out hemorrhagic stroke.
TPA administration has a narrow time window, typically within 3 to 4.5 hours from stroke symptom onset. Earlier treatment within this window leads to better outcomes. Beyond this timeframe, TPA’s benefits diminish, and risks may outweigh advantages.
Eligibility criteria are assessed before TPA is administered. These include maintaining blood pressure below 185/110 mmHg and evaluating for conditions like recent major surgery, head trauma within three months, or a history of intracranial hemorrhage. Blood tests check for clotting abnormalities or low blood sugar that could make TPA unsafe. If a patient does not meet all specific criteria, TPA risks may outweigh benefits.
Potential Benefits and Risks of TPA
TPA benefits eligible ischemic stroke patients. It significantly improves outcomes by dissolving clots and restoring brain blood flow. This limits brain damage, potentially reducing long-term disability and increasing functional recovery. Studies show patients treated within three hours of symptom onset are more likely to experience minimal or no disability.
TPA carries potential risks, primarily due to its clot-dissolving action. The most serious risk is bleeding, particularly inside the brain, known as intracranial hemorrhage. Serious bleeding into the stroke area occurs in approximately 6% of TPA recipients, compared to less than 1% in untreated patients. Other side effects include allergic reactions or temporary blood pressure drops.
The Critical Role of Timely Treatment
In stroke care, “Time is Brain” underscores the urgency of immediate medical attention. Each minute of untreated ischemic stroke can irreversibly damage millions of brain cells. Prompt symptom recognition and rapid transport to a specialized stroke center are important for TPA eligibility and effectiveness.
Upon hospital arrival, a rapid assessment begins, including immediate brain imaging (e.g., CT scan). This evaluation determines stroke type and TPA suitability. Hospitals strive for a “door-to-needle” time, administering TPA within 60 minutes of arrival to preserve brain function.