According to the World Stroke Organisation, 1 in 6 people in the world will suffer a stroke in their lifetime.
The Global Burden of Diseases study indicated a 26 percent increase in global stroke deaths during the past two decades.
The estimated incidence of stroke has increased more than 100 percent in low and middle income countries including India over last four to five decades. The risk of stroke-associated mortality is 22 times that of infectious diseases such as malaria and tuberculosis.
Why is Stroke a Medical and Surgical Emergency?
A stroke also called cardiovascular accident (CVA) affects the arteries which carry oxygen and other essential nutrients to the brain.
Stroke is a medical and surgical emergency. Time is very critical (so we call “Time is Brain”) in stroke management. This is because millions of neurons or nerve cells are lost every minute if the obstructed clot is not dissolved or removed. Once the neurons die, they cannot be revived, and clinical symptoms persist.
Pre-hospital management for stroke patients is imperative. Early identification of symptoms and seeking immediate medical help is decisive.
Identifying stroke and increasing public awareness helps in early recognition of this catastrophic but treatable emergency. The sooner treatment is given the more the damage can be minimised.
What is Mechanical Thrombectomy (MT)?
Modern neurointervention and endovascular technique has revolutionised stroke treatment. With advanced technology, the brain clot can be removed easily and more effectively within less time.
The widely accepted newer technique, mechanical thrombectomy (MT), has been found to be treatment of choice (Class 1A evidence, AHA guideline) in ischemic stroke, especially large vessel occlusion.
The newer technique provides significant edge over earlier non-invasive intravenous clot dissolving drug, for ensuring early restoration of blood supply to brain.
Treatments in India have so far focused on dissolving or aspirating the blocks over a period of time and have had limited success.
Mechanical thrombectomy (MT) is a minimally-invasive surgery in which a stroke interventionist uses specialised device to remove a clot from a patient’s blocked artery in the brain. With improved awareness and more number of expertise, number of patients or prevalence of acute stroke patients benefiting from MT has increased.
However, it is less than six to seven percent, as total number of stroke patients who report in hospital within the golden period in even less than that. Public awareness and comprehensive stroke care program will certainly help in benefiting more patients.
How is the MT Surgery Performed?
During MT, under fluoroscopy guidance, the doctor guides their instruments through the patient’s arteries to the clot, extracting it from the patient all at once. The doctor starts the procedure by making a few millimetres small incision in either the groin to access an artery.
Following this the interventionist threads a catheter through the artery to reach to the artery supplying the brain and which has been occluded by the clot.
Once the microcatheter is placed in the desired position in the brain artery with the help of roadmap, we insert a tiny net-like device called a stent retriever into the catheter and guide it to the blockage.
At this point, with the help of deployed stent retriever we jail and engage the blot clot, able to pull the whole thing backwards, removing the clot entirely.
Clot aspiration is another very promising technique of performing successful MT in stroke patients. Expertise, hardware availability, and more importantly an in-hospital comprehensive stroke program is crucial for successful MT and better outcome.
From simple stent retriever, we evolved to other effective, early first pass reperfusion technique (to take out brain clot) like our own master-hand “DAFT” (Dual Aspiration and Fluff Technique). This has significantly augmented salvaging the under-stress brain tissue (penumbra) from getting permanent neurological damage after brain attack.
Mechanical thrombectomy has also helped in improving the window of stroke treatment from six to 24 hours.
It is twice as effective, the clot which is the root cause of the stroke is completely trapped by a special device called the ‘stent retriever’ and then extracted without open surgery. This restores blood flow immediately and revives dying brain cells, thereby reversing stroke damage.
Recently, we observed that in more than 90 percent of patients, brain blood clot could be successfully removed from the brain.
However, clinical improvement does also depend on “already damaged area of brain”, before reaching hospital.
(Dr Gaurav Goel is an Associate Director of Institute of Neurosciences at Medanta.)