hotline no.
+91 124 4141414
Medanta Institute of

Dr. Ajaya N Jha
Institute of Neurosciences

Slideshow Image 1 Our Institute is dedicated to the "patient first" with a team of specialists working together, along with the best technology available today to optimize patient outcome.
read more>>

What is thrombolysis and what's a penumbra zone?
When blood flow to the brain stops, brain cells are deprived of oxygen and nutrients. Stroke is a medical emergency because brain cells start dying quickly and the treatment is most effective when given promptly.

Although some of the cells die within few minutes, surrounding zones though hypoperfused receive just enough oxygen from Cerebral Blood Flow (CBF) to stay alive. A compromised cell can survive for several hours in a low-energy state and is called “penumbra”. If blood flow is restored within this narrow window of opportunity, then some of these cells can be salvaged and become functional again. Blood flow to these cells can be achieved by administrating the clot-dissolving thrombolytic agent t-PA by intravenous and intra-arterial routes.
Who are the right candidates for thrombolysis?
Patients who are able to reach hospital before major infarct has taken place and fulfill the criteria for thrombolysis are the right candidates. Patients with hemorrhage or well-established acute infarct on CT /MRI sequence may not be the right candidates. According to the criteria, patients with hypodensity in less than third of MCA territory on CT scan are eligible for thrombolysis.
When is thrombolysis avoided?
Thrombolysis is not done on patients who are likely to have hemorrhage with use of thrombolytic drugs. The contraindications include:
  • CNS lesion with high likelihood of hemorrhage s/p chemical thrombolytic agents (e.g., brain tumors, abscess, vascular malformation, aneurysm, contusion)
  • Established bacterial endocarditis
  • There are many relative contraindications including mild or rapidly improving deficits, stroke within 3 months, history of intracranial hemorrhage and major surgery within past 14 days. The complete history is always checked before performing the procedure.
What are the likely benefits and risks of thrombolysis?
In the NINDS trial favorable outcomes were achieved in 31% - 50% of patients treated with rtPA, as compared with 20%-38% of patients who were given placebo. The benefit was similar a year after the stroke. The major risk of treatment was symptomatic brain hemorrhage, which occurred in 6.4% of patients treated with rtPA and 0.6% of patients given placebo. However, the death rate in the 2 treatment groups was similar at 3 months (17% versus 20%) and a year (24% versus 28%). In the NINDS trial there was 11-13% absolute increase in the number of people who had minimal or no disability. When tPA was given within 3 hours of onset of symptoms, the number needed to treat for 1 more patient to have a normal or near normal outcome was 8, and the number needed to treat for 1 more patient to have an improved outcome was 3.
When is intra-arterial thrombolysis done?
At present intravenous therapy is not recommended beyond 3 hours, although in some cases it may be done up to 4.4 hours. Intra-arterial thrombolysis can work up to 6 hours. Therefore patients reaching hospital between 3 to 6 hours can benefit by intra-arterial therapy. The window period can be further extended in cases of posterior circulation stroke. Patients with major vessel blockage such as internal carotid, middle cerebral artery and basilar artery are unlikely to respond to intravenous thrombolysis and can be treated better by intra-arterial means.
What is the role of mechanical means of re-vascularziation in acute stroke?
One of the disadvantages of using thrombolytic drugs is the risk of bleeding. Another problem is with large vessel blockage, thrombolytic drugs are not effective. These drugs cannot be used in many situations. To avoid these problems, mechanical means can be used to take out the clots and open up the blocked brain blood vessel. One device used for this is ‘penumbra device’ in which special catheter can be taken up to the clot to be aspirated. Medanta- The Medicity is the first center in which such procedure was performed in North India.
What should one do if one sees a patient who is a possible candidate for thrombolysis?
One should get a CT scan done immediately to rule out bleeding. If there is no bleeding and patient is within the window period then one should transfer the patient immediately to a centre with thrombolysis facilities. No anti-platelet should be given to these patient before thrombolysis. Antiplatelets are provided after 24 hrs, post excluding hemorrhage by repeat CT scan in thrombolysed patients.

Download PDF

Find a Doctor

This is content box Three
Newsletter Subscription