A stroke occurs when the blood supply to a part of the brain is cut off. Brain cells get damaged or die. Prognosis depends on which part of the brain is affected and how quickly the patient is treated. The interruption of blood supply may be due to the clogging of a vessel – causing an ischemic stroke, accounting for 80% of all strokes; or bleeding from a ruptured vessel – a hemorrhagic stroke. The brain is an extremely complex organ that controls various body functions and damage to a part of the brain leads to the loss of function of the area supplied by it. If the blood flow to the region that controls the leg is cut off, it will result in muscle weakness, causing a limp.
Stroke is a leading cause of death in India after a heart attack and cancer. From individual lifestyle choices to global policy changes – we can all help in preventing stroke. Though we do not have a proper database, we can take a sobering lesson from the following American statistics. Every 53 seconds someone in the USA has a stroke and 6.5 million people die from stroke per year. About 26 million stroke survivors are alive today and stroke costs the country between $30 billion to $ 40 billion per year. Far worse than its mortality rate is the morbidity as it leaves two out of three victims disabled for life. People think it is something which happens to the aged and yet nearly a third of the patients are under 60 years of age. 1 in 6 people will have a stroke in their lifetime.
Unlike cancer and heart disease, which are extensively publicised, public knowledge on strokes is much less. Most of us know the risk factors that lead to heart diseases such as high cholesterol and high blood pressure and diabetes. Stroke shares many of these risk factors — in fact, the two diseases coexist quite often. The modifiable risk factors are high blood pressure, cigarette-smoking, diabetes, high blood cholesterol and lipids, physical inactivity, obesity and the presence of heart disease.
A temporary interruption of blood supply can cause a Transient Ischemic Attack (TIA) or mini-stroke.Timely treatment of a TIA affords dramatic relief. The symptoms of a TIA last from a few seconds to 24 hours. They do not themselves cause permanent neurological damage but are the precursors to a major stroke. They need a quick diagnosis and treatment as well as appropriate follow-up to prevent future injury. Ministrokes are often underdiagnosed. The National Stroke Association (USA) study showed that 2.5% of all adults aged 18 or older (about 4.9 million people) have experienced a confirmed TIA. An additional 1.2 million Americans over the age of 45 have most likely suffered a mini-stroke without realizing it. Though we do not have reliable data for the Indian population we must learn from these figures. These findings clearly show that if the public knew how to spot the symptoms of a stroke, especially ministrokes, and sought prompt medical treatment, thousands of lives could be saved and major disability could be avoided.
The problem is that the symptoms of a ministroke may be subtle and temporary. The symptoms to watch out for are:
* Trouble in seeing in one or both eyes.
* Numbness or weakness in the face, the arm or the leg especially on one side of the body.
* Difficulty in walking, dizziness, loss of balance or coordination.
* Confusion and difficulty in speaking or understanding.
* A severe headache with no known cause.
One of the most important causes of a stroke or mini-stroke is a blockage in the artery to the brain — the internal carotid artery. The block is a cholesterol plaque or atheroma. The disease is called extra-cranial carotid artery stenosis and it affects the artery as it courses to the brain under the muscles of the neck. It can be easily diagnosed by a thorough examination and a simple test called a carotid doppler. In this, the doctor is able to look for a block by a simple scanner called a doppler which is applied over the neck. There is no injection or anesthesia required for this test. If the block is more than 75% and the patient is symptomatic, surgery is indicated. The treatment is a delicate but very simple and effective procedure called carotid endarterectomy (CEA). Simply put, the surgeon removes the block in the carotid artery and repairs it. It can be performed under local or general anesthesia. During the surgery, while the artery is clamped to repair it, the blood supply to the brain may be maintained by the use of a shunt which temporarily bypasses the block. For the repair, the surgeon may use a piece of vein from the patient’s own leg or a special biocompatible cloth (Dacron or PTFE — poly tetra fluoro ethylene). Special magnifying loupes and very fine sutures, which are not readily visible to the naked eye, are used for the repair. A stenting is also a good second-best alternative. The author has a good experience of treating patients with surgery over the last 20 years. The results are gratifying as the risk of developing a major stroke is reduced. Roughly, out of a population of a million people, there are about 50-100 persons who would benefit from carotid endarterectomy or stenting. Elective surgery carried out in ideal conditions with the patient (and the surgeon) in a good condition will always have a better result than surgery carried out as an emergency procedure.
The present proactive policy towards stroke prevention evolved from several discoveries dating back to the late eighteenth century when William Osler observed that emboli to the brain originate from the heart and from the arch of the aorta and the carotid artery. This finding has since been corroborated by heart surgeons and by a large number of trials involving thousands of patients which all conclusively point to a significant advantage (in the form of reducing stroke and death) of early surgery on symptomatic patients or even asymptomatic patients with severe blocks. These trials are the North American Symptomatic Carotid Endarterectomy Trial (NASCET), the European Carotid Artery Surgery Trial (ECST), the Asymptomatic Carotid Atherosclerosis Trial (ACAS), the Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST) and the Asymptomatic Carotid Trial (ACT I).
In an acute stroke, it is imperative to reach a hospital with a stroke unit as early as possible. After immediate examination and imaging with CT or MRI – a good percentage of patients can be helped with clot busters given intravenous or direct into the clot. Time is of paramount importance as delay can lead to permanent damage.
Stroke is thus not an unavoidable certainty of life. It is not the “stroke of luck”. About 80% strokes can be prevented and the morbidity and mortality associated with this killer disease can be greatly reduced by lifestyle changes, the control of risk factors and surgery where indicated.
How to reduce your risk of stroke
Did you know that 90% of strokes are linked to 10 avoidable risks? If you have diabetes, heart problems or history of stroke/TIA talk to your doctor about stroke risk and preventive treatments.
1. Control high blood pressure
2. Do moderate exercise 5 times a week
3. Eat a healthy, balanced diet (high in fruit/vegetables, low in sodium)
4. Reduce your cholesterol
5. Maintain a healthy BMI or waist to hip ratio
6. Stop smoking and avoid second-hand exposure
7. Reduce alcohol intake (men: 2/day, women: 1/day)
8. Identify and treat atrial fibrillation
9. Reduce your risk from diabetes, talk to your doctor
10. Get educated about stroke
Dr. Harinder Singh Bedi,
The author is MCh, FIACS (Gold Medalist) and is Chairman, Cardio Vascular Endovascular & Thoracic Sciences, Ludhiana Mediways Hospital, Ferozpur Road. He was earlier at the Escorts Heart Institute New Delhi and the St Vincent’s Hospital Australia.He is a member Editorial Board, Cardiology at Specialty Medical Dialogues.He has specially written this article as today is World Stroke Day and this will contribute towards creating awareness about the prevention and treatment of stroke, a leading cause of death and disability.