Stroke is now becoming the 2nd largest killer disease after heart attacks. Alarming figures suggest that the number of strokes may triple from the present level by the year 2025. At present, nearly 20,000 keralites suffer from a stroke or brain attack every year. 5000 patients die immediately or shortly after a stroke. Another 5000 patients are left severely disabled and around 10,000 people are left with some form of disability after stroke. Of all these patients, nearly 20-30% (4000 to 6000) have a significant block in their arteries to the brain as a direct cause of ischemic stroke. Half of these patients have blocks in the large arteries that run from the heart to the brain in the neck. The other half have blocks in smaller arteries that lie inside the skull. Hitherto the management of these blocks has been difficult and dangerous.
What are stents?
Stents are small metal tubes that are used to treat and open up narrowed or weakened arteries in the body. Arteries are blood vessels that carry nutrient rich blood away from your heart to other parts of body. Stents are usually placed in an artery as part of a procedure called angioplasty, where a small balloon is inflated inside a blocked artery to open up the artery and then the stent is placed inside the artery. Angioplasty restores blood flow through narrowed or blocked arteries. Stents help prevent the arteries from becoming narrowed or blocked again in the months or years after angioplasty. Stents usually are made of metal mesh. Some stents are coated with medicines that are slowly and continuously released into the artery. These stents are called drug-eluting stents. The medicines help prevent the artery from becoming blocked again and these types of stents are very helpful in certain types of patients where the chances of blockages are high.
Fig 1. Carotid Stenting in the artery in the neck:
What is so Different about Stents in the Brain?
Unlike the blood vessels to the heart which are much more easily traversed and for which a multitude of devices exist for recanalisation of blocked arteries, the arteries to the brain are smaller, more tortuous to navigate and much more fragile. For decades, cardiologists have placed millions of stents in arteries to the heart to benefit patients from heart attacks. The field of neurology has lagged behind and until recently, interventional neurologists had to use the commonly available coronary stents for arteries to the brain arteries. However stents made for the heart were difficult to navigate up into the small vessels of the brain. Many complications and failed procedures resulted, giving the treatment modality a bad reputation. With better imaging techniques such as 3D rotational angiography, we can now identify precise blocks even in small arteries of the brain and quantify them much better than before. Only in the recent years stroke research and treatment has accelerated and a number of new treatment options are now available. Newer devices such as self-expanding stents and better catheters have helped interventional neurologists reach areas of the brain with stents which were previously inaccessible. As a result, the procedure has become much safer, less complicated and more beneficial to stroke patients. We can now identify blocks in arteries as small as 2 to 2.5 millimeters in size and place appropriate stents in them. Another common site of block in the arteries to the brain is in the neck in the carotid arteries. A safe and easy procedure to open up the arteries is called carotid stenting, where a large nitinol stent is placed inside the carotid artery. Carotid stenting is far easier to perform than stenting inside the brain. The cost of carotid stenting comes to around ninety thousand rupees whereas that of intracranial stenting comes to around two lakh rupees.
Fig 2. Stent in an artery inside the Brain:
Fig 3. Stent inside a small Artery in the Brain. (Blue arrow):