Moreover, initiating tPA treatment beyond 4.5 hours (i.e., delayed tPA treatment) has been associated with deleterious side effects, notably, hemorrhagic transformation (HT) which could lead to high mortality in stroke patients [4].
When NOT to Administer tPA? For the 3 to 4.5 hours from the moment of the stroke, the benefits of tPA outweigh the risk. Studies show that after that window, the benefits of tPA drop significantly. Another factor that should be taken into consideration is the presence of a very large blood clot.
When administered quickly after stroke onset (within three hours, as approved by the FDA), tPA helps to restore blood flow to brain regions affected by a stroke, thereby limiting the risk of damage and functional impairment.
Although beneficial within 4.5 hours of stroke onset, administering recombinant tissue plasminogen activator (tPA) beyond that window appears to increase the risk of dying, a pooled analysis of eight clinical trials showed.
Alteplase (IV r-tPA) within 4.5 hours of stroke onset remains the standard of care for most ischemic stroke patients.
Moreover, initiating tPA treatment beyond 4.5 hours (i.e., delayed tPA treatment) has been associated with deleterious side effects, notably, hemorrhagic transformation (HT) which could lead to high mortality in stroke patients [4].
Symptomatic intracranial hemorrhage after IV tPA for ischemic stroke occurs in 2% to 7% of patients.
The NINDS trial indicated that with or without IV tPA, the mortality is very similar (17% among the IV tPA group, 21% among the placebo).
The utility of intravenous thrombolytic therapy within 3 hours after symptom onset in patients with ischemic stroke has been clearly demonstrated; the NNT to prevent 1 death or disability is 7 in this time window.
Two major life-threatening complications of administration of tPA for ischemic stroke include angioedema and symptomatic intracranial hemorrhage. Angioedema is usually benign and self-limited, however one must be vigilant to signs of developing airway compromise and be ready to intubate.
Background and purpose: According to evidence-based clinical practice guidelines, patients presenting with disabling stroke symptoms should be treated with intravenous tissue plasminogen activator (IV tPA) within 4.5 h of time last known well.
Thrombolysis – "clot buster" medicine
This use of "clot-busting" medicine is known as thrombolysis. Alteplase is most effective if started as soon as possible after the stroke occurs – and certainly within 4.5 hours.
tPa Clot-Busting
Called a stroke, this blockage means part of the brain may not be getting the oxygen and nutrients it needs. If treatment is delayed, parts of the brain may die. Patients may then experience certain symptoms, such as slurred speech or the inability to move arms or legs.
Emergency IV medication.
An IV injection of recombinant tissue plasminogen activator (TPA) — also called alteplase (Activase) or tenecteplase (TNKase) — is the gold standard treatment for ischemic stroke. An injection of TPA is usually given through a vein in the arm within the first three hours.
The antidote for tPA in case of toxicity is aminocaproic acid.
Ischemic stroke
If you arrive within four-and-a-half hours of the onset of the stroke, you might receive a medication called IV tPA (intravenous tissue plasminogen activator). This is a protein that your body makes to break up clots.
The reason the first hour is golden is because stroke patients have a much greater chance of surviving and avoiding long-term brain damage if they arrive at the hospital and receive treatment with a clot-busting drug called TPA within that first hour.
4.5 Hours – The Golden Period to save a life.
What are the potential risks? The major risk of TPA therapy in stroke patients is that they will bleed into the brain, causing a worsening of their condition and even death.
Patients with acute ischemic stroke who receive tPA are admitted to intensive care unit (ICU) for close monitoring and frequent neurochecks, especially because of risk of major bleeding with tPA.
Tissue plasminogen activator (tPA) is a thrombolytic. tPA improves the chances of recovering from a stroke. Studies show that patients with ischemic strokes who receive tPA are more likely to recover fully or have less disability than patients who do not receive the drug.
TPA treatment has risks. There is approximately a 3% chance of symptomatic bleeding (symptomotic hemorrhage) into the brain (because TPA thins the blood) compared to 0.2% if TPA is not given. If bleeding into the brain happens after TPA is given, it may cause your stroke symptoms to be worse and may result in death.
Tissue plasminogen activator (tPA), an approved coronary thrombolytic agent, can cause serious bleeding. We report the cases of six patients with intracranial hemorrhage after tPA treatment for acute myocardial infarction.
The National Institute of Neurological Disorders and Stroke (NINDS) study suggested that 8 out of 18 stroke patients who receive tPA according to a strict protocol will recover by three months after the event without significant disability.