Stroke and Interventional Neurology - Interview with Dr.Shakir Husain
Dr Shakir Husain is one of the very few qualified interventional neurologist in India and considered as the foremost neurointerventionist in the Asia pacific region. He obtained his qualification in interventional neurology from University Hospital, Zurich, Switzerland in 1999. As a pioneer in this field in India, he has initiated several programs for training neurologist in interventional procedures. He is a highly respected author, teacher, and researcher and has published several original works in top medical journals. He is currently director of Interventional Neurology, Max Institute of Neurosciences, New Delhi. The following is a short interview with him on stroke and interventional neurology. For further questions, you may contact him through the information displayed at the end of the interview.
Most hospitals in India do not have interventional neurologists. Is the outcome of stroke different if the patient got admitted in a hospital with neurointerventional facilities. If so how significant is the difference?
The outcome of stroke management through the Interventional Neurological approach has significantly better results. Conventional acute stroke therapy ( IV thrombolysis) is effective only if given within 4 hours of suffering the stroke. The window of opportunity is much larger with Interventional Neurology. Revascularization can be achieved by intra-arterial thrombolysis and mechanical thrombectomy for up to 6-8 hours for the internal carotid artery territory and up to 24 hours in a basilar artery stroke.
Many people who suffer stroke present late to the hospital and this may possibly reduce the amount of salvageable brain tissue. Lack of awareness among people is the primary reason. What are the commonest early symptoms prior to paralysis that should alert an individual to seek medical care?
The symptoms and signs of stroke are diverse and depend on the area of the brain affected and the functions performed by it. Common warning signs of stroke include:
1) Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
2) Sudden confusion, trouble speaking or understanding
3) Sudden trouble seeing in one or both eyes
4) Sudden trouble walking, dizziness, loss of balance or coordination
5) Sudden, severe headache with no known cause
Does prior family history of stroke increase the risk of predisposition to stroke in an individual? Other than lifestyle changes like reducing fat, adequate exercise, stop smoking and reduce alcohol, is there any other modifiable factor that can reduce the risk of stroke?
A family history of vascular risk factors (such as hypertension, diabetes, and stroke) makes people vulnerable to stroke at a younger age. Other than the lifestyle modifications you mentioned, taking adequate vitamin B-complex (from natural sources like fresh green vegetables, fruits etc.) is important in reducing the risk of stroke.
Considering the huge cost of treating patients with stroke, the morbidity associated with it and the disruption it causes in the family, many people would be happy to undergo screening for assessment of stroke risk earlier in life. Carotid doppler may be used to study the degree to atherosclerotic block in carotid arteries. But the assessment of vertebral and other intracranial arteries by non-interventional methods is difficult. What are the screening tools you recommend to assess the risk of stroke and at what age should one undergo these tests?
MR angiography of neck and intracranial vessels is a useful and non-invasive screening test to evaluate intracranial disease.
Cardiologists routinely use angiograms to assess the coronary vasculature. By a similar analogy, intracranial vasculature could also be studied to assess atherosclerosis. While angiograms are done routinely on all patients with symptoms of coronary artery disease, why is intracranial vasculature not studied?
Cerebral-DSA is an invasive test and though, it is quite a safe procedure in expert hands, it carries small theoretical risk. Therefore, non-invasive test to screen disease conditions are always preferred. However, once any atherosclerotic narrowing is detected by MRA or CT angiography, a cerebral - digital subtraction angiography (DSA) is performed to study brain haemodynamics and plan further interventions. Cerebral DSA is also done on a priority basis in young patients with minor strokes.
Suppose a carotid Doppler detects 50% block in both carotids, do you manage conservatively or do you place a stent? What amount of block warrants a stent placement? Are there any studies comparing the outcomes of those who were placed stents and those treated conservatively, because some recent studies in cardiology suggest that coronary stents are in no way superior to conservative medical management?
In a patient with no previous symptoms of stroke (asymptomatic), we recommend carotid stenting only if the block is more than 80%, while in symptomatic patients a block of 70% or more is a strong indication for carotid stenting. There have been several studies including NASCET, ACAS and more recently the CREST trial that prove the benefit of stenting/CEA over conservative medical treatment. I would like to mention here that, carotid stenting or carotid endarterectomy is performed to prevent future risk of stroke in a normal person with high risk of future stroke due to severe blockage in carotid artery(ies), it justifies its benefit only if it is performed by an Neurointerventionist with a procedural risk of less than 3% proven through his/her results. (as provided in international guidelines)
Most people admitted with ischemic stroke are diagnosed radiologically and started on conservative medical management with antiplatelets and other drugs. Interventional neurology offers the option of thrombolysis. For a given patient presenting with stroke, when do you go for thrombolysis and when do you decide to manage him conservatively? Are there any specific criteria for deciding the options? Also thrombolysis has bleeding as a potential adverse effect. What is the incidence of intra cerebral haemorrhage in patients with stroke who underwent thrombolysis?
Thrombolysis is the most physiological and definitive way to treat stroke and to reverse the neurological deficits as a fast recanalisation of the blocked brain artery revives the damaging brain and reverses stroke. Thrombolysis should be done as soon as possible to obtain maximum benefits of this approach. It is recommended that if a patient can reach a hospital before 3 hours of onset, s/he may be considered for intravenous thrombolysis. However, if a patient reaches later, then Intra-arterial thrombolysis can be considered for carotid artery stroke for up to 6 hours after the onset of symptoms and for basilar artery strokes for up to 24 to 36 hours after onset. Compared with Intra-Venous therapy, IA therapy offers several advantages, including a higher concentration of clot busting agents delivered to the clot target, a lower systemic exposure to drugs, and higher recanalisation rates. Disadvantages include additional time required to initiate therapy and its availability only at a few specialized centers Moreover, in cases where IA thrombolysis is not effective, new devices like MERCI and TREVO may be used to perform mechanical thrombectomy.
The inclusion/exclusion criteria for thrombolysis are a normal CT scan, no major surgery in the previous three months, no gross derangement of BP and blood sugar; and patient consent. The incidence of intra cerebral haemorrhage in patients with stroke who underwent thrombolysis is about 5% in IV thrombolysis and almost the double in IA thrombolysis.
Other than thrombolysis for acute stroke and carotid artery stenting, what are the other common interventional procedures done by your team?
We perform mechanical thrombectomy, Basilar and middle cerebral artery stenting, vertebral stenting, repair of dissection, brain aneurysm coiling, brain and spinal AVM embolization, repair of the brain vessels injury related to both surgical or sports and motor vehicle accidents, thrombolysis in venous sinus thrombosis, pre-operative brain and spinal tumor embolization, vertebroplasty and endovascular procedures in children with vascular lesions like vein of Galen aneurysmal malformation, brain AVM etc.
It seems India doesn't have sufficient interventional neurologists to serve its billion plus population. Based on your experience how many Indian neurologists do you think are trained in interventional procedures? Do you have any neurointerventional programs for training neurologists at your centre? How does one apply for it?
At present there are only a handful of Interventional Neurologists for this vast country. In an attempt to fill this gap, we have instituted a one-year fellowship program in Interventional neurology at Max Institute of Neurosciences for the DM-Neurology/Neuroradiology or MCh-Neurosurgery candidates, with candidates applying in January or July every year. In addition, we have established the Stroke and Neurointervention Foundation (SNIF) which aims to educate general audiences about stoke and train physicians in stroke and Interventional Neurology. The foundation provides scholarships to deserving candidates. In the last five years, we have trained more than 30 neurologists and neurosurgeons from India, Southeast Asia and the Middle East. We also conduct an annual training course "Delhi Course" in Neurointervention. The 6th Delhi Course concluded last month. The 7th Delhi Course will be held in Feb 2012.
Dr. Shakir HUSAIN MD, DM(Neurology), FINR(Switzerland)
Director, Department of Interventional Neurology
Senior Consultant, Neurology
Max Institute of Neurosciences
MAX Superspeciality Hospital
Saket, New Delhi - 110017, INDIA
Mobile : +91-98-101-20942