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ARE YOU ‘STROKE’ SMART?
INTERVENTIONAL TECHNIQUES IN STROKE MANAGEMENT – PART III
By M. P. RAVINDRA NATHAN, MD, FACC, FAHA
The most important target for therapy in acute ischemic stroke is restoring the patency of the blocked artery by removing the clot inside – ‘recanalization’ – because it undoubtedly improves the outcomes. Although administering the clot buster ‘tPA’ is the standard of care, unfortunately, only less than 10 percent patients brought to the emergency room are eligible to receive this drug because of the many contraindications, potential serious complications and the limited time window during which it can be used. Hence, mechanical clot removing devices have become quite useful and popular.
One such device is called ‘Merci Clot Retriever.’ The interventional neurologist threads a tiny catheter equipped with a corkscrew shaped coil through the brain’s delicate arteries to the site where clot is lodged, snags it and pulls it back. If you would like to watch a video animation of this innovative technique, go to google.com and search for ‘merci clot retriever device.’
There is yet another technology, the Penumbra Stroke System, in which a catheter is threaded to the site of clot formation. Then a separator is advanced and retracted through the catheter to dislodge the clot and a suction device grabs hold of it for aspiration. Sometimes, inflating a balloon (like in treating an acute heart attack with primary angioplasty) and placing a stent through the clot may also restore the blood flow in the blocked artery. The window of opportunity for these mechanical clot retrieval treatments is about eight hours from the onset of symptoms.
What about hemorrhagic strokes?
A hemorrhagic stroke – 50,000 in North America each year – occurs when a blood vessel in the brain ruptures and is associated with severe headaches followed by stroke. Often, this occurs from the rupture of an aneurysm (a blood-filled pouch with weak walls or congenital arteriovenous malformations called AVM in the brain). This is especially true of ‘Subarachnoid hemorrhage,’ which presents with the worst headache of patient’s life. Three treatments are available. The first one is packing the aneurysm with a platinum coil placed through a mircrocatheter into the body of the aneurysm disrupting and blocking the flow within the aneurysm and shutting off its orifice. This is called ‘coiling’ the aneurysm. The second one is clipping the stalk of the aneurysm with a titanium clip, an open surgical approach.
The third approach is embolization, a non-surgical, minimally-invasive procedure for selective occlusion of blood vessels by purposely introducing emboli (or special particles). This is done by interventional neuroradiologists. These particles include gelfoam, acrylic gelatin microspheres, liquid embolic agents, etc. If you want to watch an amazing video of how an AVM is being treated this way in real life, log on to: http://www.dmc.org/VideoLibrary/ShowVideo.aspx?Library=1&VideoID=107
If the stroke is secondary to occlusion (stenosis) of an extracranial artery such as carotid arteries in the neck, then treatment is easier and would include either carotid artery stenting or surgical endarterectomy – cleaning and repairing the artery. This also is done as a preventive measure for symptomatic carotid stenosis before a major stroke occurs.
Recovery after stroke
Even if the patient suffered a stroke in spite of the best treatment, there is still hope for decent recovery. Such recovery is dependant on aggressive physical, occupational and speech therapy. There are comprehensive rehabilitation institutes attached to stroke centers and also independent ones. They do a fantastic job and at the end of the first six months when the recovery from stoke is optimal, most patients are able to walk with some aid. I have seen patients virtually bed ridden during the first week of a stroke getting up and walking with a cane after three months of therapy. So, don’t lose heart even if you or your loved one suffered a stroke.
Modern medicine is driven by technology that is making a big difference in the final outcome for patients. Almost any culprit lesion inside a blood vessel such as a stenosis, clot, aneurysm, AVM, etc., can be imaged and defined by the newer endovascular imaging technologies that hold a valuable role in patient selection and preoperative planning. “Endovascular intervention” – consisting of the above mentioned techniques – is an emerging frontier ready to revolutionize our treatment methods and patient outcomes in acute strokes, one of the most dreaded diseases in medicine.
Needless to say community awareness is of paramount importance.
Dr. M.P. Ravindra Nathan is a Brooksville cardiologist and director of the Hernando Heart Clinic.
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