Stroke is third most common cause of death and disability. According to WHO Survey in 1990, out of 9.4 million deaths in India 6,19,000 were due to stroke. Most of the strokes (approximately 75%) are ischameic in nature and large vessel disease accounts for approximately 40% of ischaemic strokes. It has been estimated that approximately 20-30% of strokes may be caused by stenosis of carotid artery.
Medical treatment is done for the risk factors for atherosclerosis such as hypertension, diabetes mellitus & dyslipidemia . Patients are also told to stop smoking. Anti-platelet drugs (Dispirin, clopidogrel) are useful to prevent embolic events. Patients with marked stenosis require revascularization which can be achieved by surgical (endarterectomy) or endovascular (angioplasty & stenting) means.
Asymptomatic carotid stenosis:There is no established guidelines on treatment of asymptomatic carotid stenosis. In these patients, transcranial Doppler allows for real time assessment of blood flow in the brain arteries and evaluate for risk of further stroke. Further, assessment for microemboli (small clots that cannot be visualized by other modalities) can be undertaken. Carotid artery stenting is advisable and is offered in high risk patients.
Patients who have coexisting medical problems or advanced age (>80) are better suited for stenting rather than endarterectomy. Patients having certain anatomical features such as prior ipsilateral endarterectomy, prior neck irradiation, contralateral internal carotid artery (ICA) occlusion & high cervical stenosis are also better suited for stenting as compared to endarterectomy.
Patients with marked tortuosity of the common carotid artery and ICA or contraindications to anti-platelet therapy may not be suitable candidates for endovascular therapy.
Filter protection devices are umbrella-shaped devices that are placed temporarily in the internal carotid artery beyond the site of stenosis during the procedure. These devices have small pores designed to exclude particulate debris embolization to cranial circulation during the procedure.
Many cases of stroke occur due to stenosis in vertebral & intracranial atherosclerotic disease. Recent studies have shown that these patients with intracranial stenosis have high risk of stroke in spite of medical treatment. Recent advances in technology has made angioplasty and stenting possible in these patients.
A 64-year old male presented with recurrent numbness of left side of body (transient ischaemic attacks). Carotid doppler revealed severe narrowing of right internal carotid artery. Angioplasty and stenting was done with protection device resulting in complete recanalization. Patient has been asymptomatic since then.
A 68-year old male presented with recurrent transient ischaemic attacks in right middle cerebral artery.
A 72-year-old male presented with stroke due to an ulcerated calcified stenosis at left carotid bifurcation. Stent assisted angioplasty resulted in complete recanalization, At 2-year follow-up patient is symptom free.