Advances in interventional neurology

Dr Vikram Huded, Head of Neurointervention and Stroke, Narayana Hrudayalaya Institute of Neurosciences, Narayana Hrudayalaya Hospital, Bengaluru, elucidates on the evolution of interventional neurology and the various methods that have proved beneficial in handling strokes, a major health concern

Stroke, also called as ‘lakwa’ or ‘paralysis’, is a medical emergency. Broadly, strokes can be divided into two types: ischemic stroke, where blood supply to a part of brain is blocked by clot in the vessel; and haemorrhagic stroke where blood vessel ruptures in the brain. Stroke has been among one of the leading causes of death and disability worldwide. Just in the US alone, one stroke happens every four seconds and one person dies of stroke every four minutes. According to WHO, stroke was the most frequent cause of death worldwide in 2011 with more than 40 per cent of death occurring in South East Asia. With increase in longevity, urbanisation and sedentary lifestyles the occurrence has further increased.

Stroke can happen to anyone at any point of time. Importance of recognising the symptoms at the earliest can be judged by the fact that for each minute a stroke goes untreated and blood flow to the brain continues to be blocked, a person loses about 1.9 million neurons. Sudden onset change in voice, inability to speak or understand; sudden onset face dropping, arm or leg weakness or numbness especially on one side of body; sudden onset imbalance in walking; sudden onset severe headache; or sudden onset loss of vision in one or both eye may suggest a stroke. An easier way to remember it is ‘FAST’ where ‘F’ is face drooping, ‘A’ is arm weakness or numbness, ‘S’ is speech difficulty and ‘T’ stand for time to rush to hospital which has facilities to perform thrombolysis. Only by increasing the awareness about stroke symptoms we can make sure that people reach the hospital in time and can be treated appropriately.

Till recently, there was not much to offer for treatment and management of stroke, with more emphasis being laid on rehabilitation. In the last 20 years, this scenario has changed with rapid advances in medical science, especially for treatment of ischemic strokes. The first major aspect was intravenous thrombolysis in which the medical professional attempts to lyse the clot by giving drug through injection into the vein.

Interventional neurology offers the best minimally invasive treatment for a wide range of conditions involving the brain, the head and neck region as well as the spine and spinal cord. It has taken the treatment of stroke one step ahead so that now we can go into the artery and take out the clot, thus restoring the blood flow immediately, by procedure known as mechanical thrombectomy. With the new generation clot retrievers the chances of complication have come down as well as the success rates have gone up. Also, with the advent of newer procedures, the time window in which a procedure can be performed has gone up from 4.5 hours in case of intravenous thrombolysis to six hours in case of mechanical thrombectomy. We have been doing both intravenous thrombolysis as well as mechanical thrombectomy with the help of a dedicated stroke team and a very efficient stroke protocol for the last six years. Narayana Hrudayalaya Institute of Neurosciences is the first centre in India to do mechanical thrombectomy for acute ischemic stroke. The youngest patient treated by mechanical thrombectomy by us was six years of age, which is first in Asia. Our assessment of patient data suggests the most important reason for inability to offer the treatment to patients is late arrival, mostly due to unawareness about the availability of treatment options and thus wasting crucial time.

Carotid stenting is rapidly becoming an effective non-surgical method of choice to open the blocked vessels in neck. By doing so the chances of recurrence of stroke can be effectively reduced. Stenting has also been proved to be method of choice for those who have associated diseases such as coronary artery disease or patients having arterial narrowing in neck after radiation therapy. The development of embolisation protection devices have made stenting procedures much more safe. These are sieve like devices which gather the debris formed during stenting and thus prevent occurrence of stroke during procedure.

The indications for endovascular neuro-interventions in neurology have been increasing rapidly.

Subarachnoid haemorrhage (SAH) is another such disease wherein interventional neurology is fast becoming the treatment method of choice. SAH occurs due to rupture of a bleb in the brain leading to haemorrhage. Of all the haemorrhagic strokes, 50 per cent are due to SAH. The seriousness of the disease can be gauged from the fact that about 10-15 per cent patients die before reaching hospital. The mortality rate reaches almost 40 per cent within first week and up to 50 per cent in first six months. Advances in technology has made it possible to treat the aneurysms rapidly and effectively. Using this approach, aneurysms can be cured with the help of platinum coils, even in those areas of brain were surgical access is difficult. This abolishes the chances of rebleeding and helps providing the established line of treatment to the patient. Through endovascular injection of drugs complications of SAH, namely vasospasm, can also be treated at the earliest. With the help of stents, some difficult to coil aneurysm can also be coiled. Flow diverter stents are the latest in treatment of unruptured aneurysms.

A frequently missed but not uncommon subtype of stroke is cerebral venous sinus thrombosis wherein clotting happens in vessels which drain blood out of brain called veins.. This kind of stroke is frequently seen in women in their last months of pregnancy or in early weeks after giving birth. Another group of people at risk for this are young males with habit of chronic smoking or alcoholism. Its symptoms are also somewhat different as it presents with headache with or without fits. The other characteristic symptoms of stroke may or may not be there thus, the diagnosis becomes even more difficult. Using blood thinners have been the accepted treatment protocol in this condition but it provides little benefit in those situation where the disease is in its particularly aggressive form. In such cases, we have been doing in-situ thrombolysis with very good outcomes. With the help of a microcatheter, high potency blood thinners are given directly to the clot thus reducing the need for amount of drug and potentially avoiding complications of the drug. Apart from these major indications, some rather infrequent conditions for whom neuro-intervention is the preferred method of treatment includes intracranial and spinal dural AV fistulas, arterio-venous malformations, and carotico-cavernous fistula.

In the end, it all comes down to improving the awareness of the public about the symptoms of diseases like stroke, importance of time for treatment and the availability of the newer neuro-intervention methods for treatment of those diseases. We can expect to pass on the benefit of these advances to the public. The best thing would be increasing awareness about stroke risk factors such as sedentary lifestyle, obesity, alcoholism, smoking, hypertension along with timely recognition of stroke symptoms at some point of time among school going children along with various community education programmes.