The normal process of blood clotting or coagulation is critical to prevent excessive bleeding after injury to blood vessels. However, this protective mechanism under certain circumstances can also interfere with the blood supply to vital organs such as the brain, heart, lungs by forming large blood clots that wedge inside the blood vessels. This can be a life threatening condition which requires immediate intervention and thrombolytic therapy has an important role here. Thrombolytic agents are very potent medications that can breakdown clot over a short duration of time and this allows to restore blood flow to the vital organs and prevents death and other long term complications.
What are the indications for thrombolytic therapy?
One of the commonest indications for thrombolytic therapy is in the treatment of ischaemic stroke where the blood vessels supplying the brain are blocked by clot. Some of the other indications for thrombolysis include:
- Pulmonary embolism (clot in the lung artery)
- Deep vein thrombosis (clot in the deep veins of legs)
- Clot in the heart (heart attack)
- Clot in the arteries of arms or legs
- Blocked dialysis access catheter or bypass graft
What are the contraindications?
Thrombolytic agents are potent medications with significant risk of bleeding. Hence, your doctor will have to ensure that you are safe to undergo treatment taking into consideration the risks and benefits. However, there are certain conditions where thrombolytic therapy is unsafe such as in patients with
- Brain haemorrhage
- Severe uncontrolled high blood pressure
- Severe head trauma
- Blood clotting disorders
What does the procedure involve?
Thrombolytic medication can be administered either directly through a cannula inserted into the vein (systemic thrombolysis) or via a catheter introduced into the vein or artery and manoeuvred close to the site of the blood clot (catheter directed thrombolysis).
In systemic thrombolysis, the clot busting medication is delivered through a peripheral intravenous line, usually through a visible vein in the forearm. This is performed at your bedside in an intensive care unit while your heart and lung functions are closely monitored. The medication takes effect as it flows through the circulatory system and reaches the site of the blood clot where it breaks down the clot to restore blood flow.
Catheter directed thrombolysis is performed in a specialised operating theatre equipped with sophisticated X ray machinery which allows to perform angiography. The groin is initially shaved and cleaned following which the skin is numbed with a local anaesthetic. A catheter (thin plastic tube) is then introduced over a sheath (outer sleeve) via the blood vessel (vein or artery) in the groin. This catheter is then manipulated and directed close to the site of the blood clot so that medication can then be administered directly into the clot. Progress of the thrombolysis treatment can then be assessed by contrast angiography (dye) study. The duration of the procedure can vary from a few hours to one/two days depending on the progress of the treatment. At the end of the procedure, the catheter is removed from the groin and the puncture site is compressed for 20 minutes to stop bleeding.
The clot can also be broken down by mechanical agitation using fluid jet, rotary, ultrasound or suction devices mounted on catheter tips. This facilitates clot break down at a faster pace which may be critical in certain conditions where prompt restoration of blood flow prevents permanent loss of function or damage to vital organs.
Are there any specific post-procedural care?
You will be advised to rest for several hours following the procedure to reduce the risk of bleeding from the puncture site. Medical or nursing staff will continue to monitor your progress for improvement or deterioration of the condition after the procedure. Inform your doctor or nursing staff of any untoward concerns such as increasing pain and swelling, limb discolouration or fever.
Risks & Complications
As with any procedure, thrombolytic therapy has risks and complications, mostly related to bleeding from the puncture site or into the brain. Rarely, allergic reaction to the thrombolytic agent or the contrast dye may also be observed.