Thrombolytic therapy also known as thrombolysis or fibrinolytic therapy involves the use of drugs – known as lytics – to dissolve blood clots that have suddenly blocked the arteries or veins, posing serious complications and threat to life. This therapy is also used to treat cases of stroke, where the blood clots have caused disruption of blood flow to the brain. The therapy is effective provided it is initiated timely before permanent damage has occurred. Hence, it is very critical that a person experiencing warning signs or symptoms of stroke should immediately seek medical help and get the thrombolytic therapy as soon as possible. The length of time lost between the early signs of stroke and getting medical help can alter the outcome of the therapy. It is suggested that the person experiencing stroke symptoms should get medical help within 3 hours of the first sign to reduce damage and risk to life; after reaching the hospital, the therapy should be initiated within 30 minutes. The most common drug used in the therapy is tissue plasminogen activator (tPA), though there are many other which are equally effective.
Thrombolytic therapy is one of the emergency treatments for patients experiencing a stroke or a heart attack. A stroke is medical condition in which the blood flow to the brain is restricted resulting in death of the cells. While there are two typical causes of a stroke – blood flow restriction and bleeding, the blood flow restriction to the brain tissue is the primary cause of a stroke. These strokes are known as ischemic strokes, which can be easily treated with thrombolytic therapy to dissolve the blood clots quickly, restoring the blood flow to the brain.
However, the therapy is given to the patient under the following conditions:
- When the brain CT confirms no bleeding in the brain tissue
- When the test show a significant stroke
- Medical history (previous history of heart attack, diabetes, blood pressure, heart disease, etc.)
Further, other factors that help to assess if the patient is a good candidate for thrombolytic, include age and gender.
But thrombolytic may not be given to the person, in case of the following conditions:
- Stroke or head injury in the recent past
- Bleeding issues
- Bleeding ulcers
- Recent surgery
- Severe high blood pressure
- Dislodging of clot
- Allergy to dye
- Current medication incompatible with thrombolytic drugs
- Delay in reaching the hospital
- No clarity about the onset of symptoms
Also, in case of a stroke that is caused due to bleeding in the brain, thrombolytic therapy will worsen the situation by increasing bleeding.
Types of Thrombolytic Therapy
Some of the most commonly used thrombolytic therapy drugs include, but are not limited to:
- Abbokinase, Kinlytic
Procedure of Thrombolytic Therapy
A thrombolytic therapy may take about 60 minutes typically in case of a stroke or heart attack; whereas in case of any other issue, the session can last for as long as 48 hours. The procedure either uses IV sedation or general anaesthesia depending on the condition and location of the blood clot.
During the procedure, the doctor will make a small incision typically in the knee or arm of the patient. Then a catheter – a thin, flexible tube – will be inserted into the blood vessel – vein or the artery. Once done, the doctor will guide the catheter to the exact place of the clot with the help of X-Ray machines. When the catheter is in the right location, a special contrast material – usually a dye – is inserted to enable capturing of the clot through a series of X-rays. With the help of these images, the doctor decides the best course of treatment.
In case, the clot can be dissolved with the help of medications, the catheter is connected to a pump that will provide medication at precise rate and quantity throughout the day. During the procedure, the patient is kept under intense observation and X-rays are taken to assess progress and determine the effectiveness of the therapy. In case the blood clot is small, the therapy may last for several hours.
In other case, the blood clot is dissolved by attaching the catheter to another machine that sprays a saline solution on the clot to help it break. Once the clot breaks, the machine suctions out the pieces of the broken blood clot. This procedure will need to be repeated until all pieces are removed from the body. Post the procedure; the patient might experience some pain and discomfort, which can easily be controlled with oral or IV pain medication.
Moreover, the catheter is not removed for several days to assess the effectiveness of the therapy and repeat the procedure, if needed. Once the clot is removed, the catheter is taken out and medication is stopped. The therapy helps to break down and disperse blood clot preventing blood from reaching the brain, which ultimately lead to stroke in the first place. Post this, the patient is bandaged, which must stay absolutely dry for at least 48 hours.
Risks of Thrombolytic Therapy
Even though thrombolytic therapy is safe and very effective in removing blood clots and improving the blood flow to the brain, it still has its own risks. Thrombolytic therapy relieves or eliminates symptoms and reduces the chances of a major surgery but it is not a preferred mode of treatment for all cases of stroke. In case the patient takes blood thinning medications, herbs or dietary supplements or have health conditions with a high risk of bleeding – thrombolytic therapy may not be recommended to treat stroke. Some more conditions where this therapy becomes risky and hence is not recommended include:
- High blood pressure
- Severe blood loss
- Active bleeding
- Kidney disease
- Recent surgery
- Bleeding in the brain causing a hemorrhagic stroke
Moreover, in patients that are at an advanced age or are pregnant, thrombolytic therapy can be very risky. Some risks involved in a thrombolytic therapy include:
- Serious internal bleeding
- Allergic reaction to dye
- Bruising or bleeding at the site of incision
- Damage to the blood vessel
- Movement of the blood clot to another area of the vascular system
- Kidney damage (in case of diabetic patients)
The most serious concern is the internal bleeding which can be fatal but is a rare complication.
While thrombolytic therapy is a safe and effective method in many cases, yet it might not prove as effective in other cases. This is highly dependent on case-to-case. In many conditions, thrombolytic therapy is not able to dissolve the blood clot and in some other, the blood clots also tend to redevelop causing complications. Moreover, thrombolytic therapy is not independently sufficient to treat tissue which has been damaged due to restricted blood flow. Thus, another course of medical treatment may be required to completely treat the person.