Patterns of carotid doppler findings and associated factors among adult patients with ischemic stroke at Moi Teaching and Referral Hospital, Eldoret

Abstract

Background: Acute ischemic stroke is a major cause of death worldwide. About 80% of strokes are thromboembolic in origin, with carotid plaque as an embolic source. Carotid Doppler ultrasound is valuable to assess the localization, extent, and severity of extracranial carotid stenosis. It is a safe, accurate, and affordable alternative to Computed Tomography Angiography. However, limited studies have been done in our population. Objectives: To describe the patterns of carotid Doppler ultrasound, the proportion of Internal Carotid Artery(ICA) stenosis, and its associated factors among ischemic stroke patients at Moi Teaching and Referral Hospital. Methods: This was a cross-sectional study conducted among patients who presented with a CT diagnosis of acute ischemic stroke from September 2018 to August 2019. A census methodology was used and a total of 71 participants were recruited. A data collection form was utilized to record age, gender, history of known risk factors such as diabetes, hypertension, and smoking and findings of carotid Doppler ultrasound. The 7.5 MHz linear array transducer of the Mindray M7 machine was used (Doppler angle <60º). The Mindray M7 is an ultrasound machine with superior image quality and exquisite Doppler capability. Stratification of ICA stenosis was done based on the United States Society of radiologists in ultrasound consensus criteria of 2004. Continuous variables were summarized using means and standard deviations. Categorical variables were summarized in frequency, percentages and bar graphs. Chi-square test and Fischer’s exact test were done to assess the relationship between stenosis and associated factors. Mann Whitney U test was used to determine association between distribution of age and stenosis. P value of less than 0.05 was considered significant Results: Of the participants studied, 42/71(59.2%)were male. The mean age was 64.2 years (SD=11.0). Increased Intima Media Thickness (>1 mm) was seen in 43/142(30.3%) of the common carotid arteries. 41 plaques were identified. The commonest site of plaque was the ICA 21/41(51.3%) followed by the carotid bulb 9/41 (21.9%) and the CCA 9/41 (21. 9%), where 28/41(68.3%) were characterized as homogenous, 7/41(17.1%) heterogeneous and 6/41(14.6%) were calcified. Mild ICA stenosis was seen in 20/71(28.2%) patients followed by 5/71(7%) with moderate stenosis, 2/71(2.8%) had severe stenosis while 1/71(1.4%) had near total occlusion. There was a statistically significant relation between diabetes, hypertension and smoking with ICA stenosis, P-values of <0.001, 0.025 and 0.032 respectively. Individuals with stenosis had a higher age (mean rank= 38.27) compared with those without stenosis (mean rank = 34.52). However, age and gender did not show any significant association with stenosis. Conclusion: ICA was the most common site for plaque formation, with homogenous plaques being the most common. The proportion of patients with significant stenosis was low. Having Diabetes, hypertension and a smoking history was associated with carotid artery stenosis Recommendation: Routine screening of patients above 50 years with a history of diabetes, hypertension and smoking is recommended. Prospective studies be done to further assess the strengths of association.