Tissue plasminogen activator (tPA) has helped save thousands of stroke victims since its approval by the U.S. Food and Drug Administration (FDA) in 1996. From the time of its introduction there has been caution (some would argue too much caution) regarding the window of opportunity that medical professionals have to administer tPA. Currently that window is 3 hours. Meaning that doctors can administer tPA if the patient arrives and is ready to be given tPA within 3 hours of when they had the stroke (4.5 hours for patients who fit a certain exception).
According to the CDC, there are more than 795,000 stroke victims annually, and as of 2018, 1 in every 6 deaths from cardiovascular disease was due to stroke. Most of these strokes are defined as ischemic, meaning that an artery is blocked by a blood clot, causing the attack on the brain (i.e., a stroke). For many stroke victims, especially those over 65, this means a reduction in mobility. The drug tPA is able to bust up the clots to restore blood flow, thereby saving precious brain tissue. So why not give every stroke victim tPA? The reason is that tPA is a powerful blood thinner, and with that comes a risk of bleeding inside the brain.
When NOT to Administer tPA?
For the 3-4.5 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. According to a 2016 article in Scientific American:
“Of all of tPA's drawbacks, the most troublesome is its inadequacy against big clots, which can block large blood vessels at the base of the brain; they cause about 25 to 30 percent of all strokes. Although it works well against smaller clots in narrower vessels, a safe dose of the drug—which is delivered intravenously—often does not last long enough in the bloodstream to dissolve the big clots, and increasing the dose raises the risk of bleeding.”
Other Contraindications for tPA
The National Center for Biotechnology Information, lists the following list of criteria as contraindications for tPA therapy, according to the American Heart Association:
Significant head trauma or prior stroke in the previous 3 months
Symptoms suggest subarachnoid hemorrhage
Arterial puncture at a noncompressible site in previous 7 days
History of previous intracranial hemorrhage
Intracranial neoplasm, AVM, or an aneurysm
Recent intracranial or intraspinal surgery
Elevated blood pressure (systolic greater than 185 mmHg or diastolic greater than 110 mmHg)
Active internal bleeding
Acute bleeding diathesis, including but not limited to
Platelet count less than 100 000/mm^3
Heparin received within 48 hours resulting in abnormally elevated aPTT above the upper limit of normal
Current use of anticoagulant with INR greater than 1.7 or PT greater than 15 seconds
Current use of direct thrombin inhibitors or direct factor Xa inhibitors with elevated sensitive laboratory tests (e.g., aPTT, INR, platelet count, ECT, TT, or appropriate factor Xa activity assays)
Blood glucose concentration less than 50 mg/dL (2.7 mmol/L)
CT demonstrates multilobar infarction (hypodensity greater than a one-third cerebral hemisphere)
There is no direct way to reverse the major bleeding that may occur during tPA therapy. It’s a gruesome outcome more than just a run-of-the-mill side effect. “All you need to see is one intracranial bleed from tPA, and you realize you've got to pause before you give that medication,” says Thomas Maldonado, a clot specialist at New York University's Langone MedicalCenter, as told to Scientific American.
Suffered from Medical Malpractice After a Stroke? Contact Us Today
Strokes are serious medical events that require prompt and accurate treatment. If you suffered a stroke and your physician either did not administer the proper treatment or administered a treatment incorrectly, our Baltimore medical malpractice attorneys can determine whether you have a case. You may be entitled to significant compensation for medical bills, lost wages, and more.
Call Brown & Barron, LLC at (410) 698-1717 to schedule a free consultation.