CHECK-UP: Thrombolytic therapy involves the use of drugs to dissolve clots
I'VE NOTICED that a new drug treatment for stroke has been mentioned in the media recently. Can you tell me what it's called and how does it work?
The treatment you refer to has several names including thrombolytic therapy and, more commonly, clot-busting treatment. This therapy involves the use of drugs to break up or dissolve blood clots, the main cause of stroke and heart attack.
When a blood clot forms, it can move through the circulatory system and become lodged in a small vessel. If this occurs in a blood vessel supplying heart tissue, it can result in a heart attack, where part of the heart muscle dies due to lack of oxygen. Should a clot travel to the brain it can cause blockage of a blood vessel, starving an area of the brain of blood and oxygen.
This type of stroke is called an ischaemic stroke. Thrombolysis works by dissolving the blood clot quickly, allowing the return of blood to the tissue to help prevent further damage.
While the American Heart Association has reported a better chance of survival and recovery from a heart attack if thrombolytic drugs are administered within 12 hours of the start of a heart attack, a recent European study has shown that thrombolysis treatment given up to four and a half hours after onset of stroke symptoms helps improve clinical outcomes in patients with acute ischaemic stroke.
So, should this treatment be given to everyone who presents with signs of a stroke?
No. Although most strokes are caused by a blood clot (ischaemic stroke), some strokes are caused by a haemorrhage. In cases of haemorrhagic stroke, clot- busting drugs are not given as they could worsen the damage by increasing bleeding from the damaged blood vessel in the brain.
The treatment is also contraindicated in those with a current or recent haemorrhage, severe high blood pressure, history of recent trauma, severe liver disease, acute pancreatitis, bacterial infection of the heart or active peptic ulcer disease.
How can the doctors tell which sort of stroke it is?
The only way to accurately diagnose the cause of a stroke is to perform a brain scan which needs to be done rapidly following the onset of stroke symptoms to allow the drug treatment to be given appropriately and swiftly.
Unfortunately, in the Republic we do not yet have dedicated stroke units throughout the health system so that many patients who would benefit from this therapy are unable to access it.