Digital Subtraction Angiogram
New horizon in the treatment of stroke
Dr M A Hayee is performing DSA with his team. Photo: Dr Tareq Salahuddin
Brain controls all activities of our body. Like other parts of the body, brain also gets nutrition from blood. There are many diseases of brain like stroke, tumour, different kinds of infections, trauma, degenerative diseases and so on. Among them stroke is known almost to everybody. Some of us has misconception that stroke is the disease of heart, which is not correct. Stroke is completely a disease of the brain. In a neurology unit of a hospital, more than 50 per cent are stroke patients. "About 5 lakh people get stroke every year in our country", informed Dr M A Hayee, Head of the Department of Neurology of Sir Salimullah Medical College and Mitford Hosital, Dhaka. "Many patients die of stroke. The patients who survive, usually develop various complications and become disable shortly", he added. What is a stroke?A stroke, also called brain attack is a medical emergency. Strokes happen when blood flow to the brain stops. Within minutes, brain cells begin to die. There are two kinds of stroke. The more common kind, called ischemic stroke, is caused by a blood clot that blocks or plugs a blood vessel in the brain. The other kind, called hemorrhagic stroke, is caused by a blood vessel that breaks and bleeds into the brain. "Mini-strokes" or transient ischemic attacks (TIAs), occur when the blood supply to the brain is briefly interrupted. When an area of brain gets less than 50 percent of normal blood flow due to rupture of vessels or deposition of plaque or atheroma (thickening of the walls of an artery by deposits of a fatty substance such as cholesterol) inside the vessel, the neuron (the structural and functional unit of brain) of the area die. A stroke patient's presentation of symptoms depend on which area of brain dies. Angiogram in the diagnosis of stroke
Some of you may hear about angiogram of heart i.e. of coronary vessels; some of you may have seen it; or some of you may have gone through the procedure. Now-a-days, a special type of angiogram is being used in the diagnosis of stroke and some other neurologic problems. This is called Digital Subtraction Angiogram (DSA) or cerebral DSA. The procedure is similar to a coronary angiogram. In fact, this is the study of the vessels that supply our brain (carotid and vertebral system). In our country, Dr M A Hayee is the pioneer to introduce cerebral DSA. He has done about 500 DSA of different cases. He told Star Health about different aspects of cerebral DSA. Procedure of DSA and its benefit
Cerebral angiogram or DSA is an invasive procedure. But the patients do not feel any pain during DSA. They remain alert even when the procedure is being done. Like coronary angiogram, the entry point is femoral artery (the artery which runs down the front of the thigh and then crosses to the back). Local anaesthetic drug is applied over the area so that the patient does not get any pain. A head hunter catheter is introduced which ultimately reaches the carotid and vertebral artery system crossing the great vessels of the heart. Photograph is taken inside the vascular system of the brain and a special radio-opaque dye is used before taking the photographs. Then it can reveal the stenosis or blockage of the vascular system as well as the vascular supply. The procedure is done as a day case basis. Patients can go home and go back to their normal daily activities just after 6 hours of the procedure. They are advised to stay for 6 hours just to observe if any complication develops. Sometimes the exact cause of different neurologic diseases are not completely revealed by investigations like CT scan, MRI or carotid doppler study. They may need cerebral angiogram to correlate with the clinical signs as well as other investigations for proper diagnosis and prognosis. Dr Hayee told that the main difference of DSA with doppler study is — it can reveal the condition of the collateral supply in the brain. The traditional doppler study can only say the condition of blockage, stenosis and flow, but DSA can reveal completely the collateral status. Dr Hayee also informed — if vascular supply is hampered almost 100 percent and the collateral supply is ok, the patient could be recovered much. Moreover, the procedure is important in case of taking decision before doing any neurosurgery to know the haemodynamic state of the patient. Complications or side effects of DSA
Since cerebral DSA is an invasive procedure, certainly it possesses some risks or side effects. But that is very negligible in comparison to the risks that the patients bear with themselves. "The risks during the procedure could be recovered instantly", assured Dr Hayee. He also informed that there was no case of fatality or huge morbidity among his 500 angiogram (DSA) cases. Candidates of DSA
Dr Hayee explained that following patients are suitable candidate for cerebral DSA. Stroke related causes:
* Stroke patients who presents with more than 50 blockage in the carotid system by doppler stody * Stroke at any young age, i.e. stroke at below the age of 45 * Rupture aneurysm (swelling caused by the weakening of a wall of a blood vessel) * Rupture AVM (arterio venous malformation) * Unexplained cranial nerve palsy (paralysis of nerves) * Unexplained ocular proptosis (forward displacement of the eyeball) * Unexplained unilateral dilatation of the pupil Non-stroke related causes:
* Skull base tumour e.g. Meningioma * Different neurologic insult including the fracture of head What to do after DSA
The next step is dictated by the angiogram. If there is stenosis more than 50 percent, the may be suggested to be stented according to the clinical condition. Conclusion
Dr Hayee explained well that cerebral angiogram is a sophisticated procedure. But it is very simple for an expert hand. People had to go abroad earlier to have the procedure which can be done now in the country.
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