PREVALENCE AND RISK FACTORS OF CAROTID ARTERY STENOSIS IN ISCHAEMIC STROKE PATIENTS- A CROSS SECTIONAL STUDY IN A TERTIARY CARE HOSPITAL

Background and purpose: Carotid artery stenosis is a major risk factor for stroke and for the symptomatic cerebrovascular disease. Approximately 20-30% of all ischaemic strokes are caused by carotid occlusive disease. In this study we attempted to find the prevalence of carotid artery stenosis in ischaemic stroke patients, so that aggressive secondary preventive measures can be directed to those patients. In this study we have analysedassociation between Carotid artery stenosis and risk factors such as Diabetes mellitus, Hypertension, Hyperlipidemia, Smoking, Sex and Age. Methods: It is a cross sectional Hospital Based Prevalence Study done in a sample of 100 patientswho were admitted in our hospital within 1 week of stroke during the period of july 2017 to june 2018. Patients whose duration of stroke > 2 weeks, patients with haemorrhagicstroke, patients with H/o head injury and stroke due to infectious causes were excluded. All patients were subjected to CT scan or MRI brain study and Colour Doppler study of extra cranial carotid arteries and vertebral arteries.Systolic and diastolic velocity of blood flow, carotid intimal medial thickness, presence of atheromatous plaque and thrombus was looked for and then the percentages of stenosis of the affected arteries were calculated . Results:The percentage of patients with significant stenosis (>70%) was 10% in our study. The prevalence of moderate stenosis was 12%, mild stenosis was 24% and 54% of stroke patients had no Carotid stenosis. We found in our study the percentage of patients who had Carotid stenosis, increased with increase in age1. The prevalence in patients <50 years, 50-69 years, >60 years was 30%, 43%, and 53% respectively. The majority (53%) of patients with carotid artery stenosis were older than 60 years. Hypertension was the most common risk factor present in 54% of cases either as a single risk factor or associated with other risk factors. The prevalence of carotid stenosis was more in hypertensive?s (57%) than in normotensives (32%). Elevated systolic blood pressure accelerates the progression of intima medial thickness (IMT) in the carotid artery. However isolated hypertension occurs in only less than 20% of patients with stroke and is usually associated with other risk factors that is why antihypertensive treatment alone may fail to prevent stroke. We have found that age, male sex, smoking, HT, DM and Hyperlipidemiais associated with increased rate of carotid stenosis. In our study every patient with carotid artery stenosis had one or the other risk factor for carotid atherosclerosis. In other words, there was no patient with carotid artery stenosis, without any risk factor in our study. Hence asymptomatic patients with these risk factors should be screened for carotid stenosis to prevent stroke. Conclusions- There was no patient with carotid artery stenosis, without any risk factor in our study. Hence asymptomatic patients with these risk factors should be screened for carotid stenosis to prevent stroke . About 46% of ischaemic stroke patients had carotid stenosis in our study. The prevalence of carotid stenosis increases with increase in age, male gender, smoking, DM, HT & Hyper lipidemia. Carotid stenosis and if present, should have their blood glucose, blood pressure and lipids under control and should be started on antiplatelet drugs and statins for plaque regression and for primary prevention and recurrences of stroke. Carotid endarterectomy should be done in selected cases for secondary prevention of stroke. The present study highlights the importance of Doppler sonography in stroke prevention effort through surveillance for atherosclerosis that predisposea person to cerebral ischaemia.