|Year : 2020 | Volume
| Issue : 3 | Page : 155-159
Assessment of intracranial and extracranial atherosclerosis in patients presenting with acute ischaemic stroke
B Vengamma1, Sai Neelima Challa1, B Vijayalakshmi Devi2, SV Naveen Prasad1, Pranuthi Pynam1, Rakesh Reddy1
1 Department of Neurology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
2 Department of Radiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
|Date of Submission||21-Jun-2019|
|Date of Decision||15-Apr-2020|
|Date of Acceptance||16-Apr-2020|
|Date of Web Publication||27-Oct-2020|
Director-Cum Vice-Chancellor, Senior Professor and Head, Department of Neurology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andra Pradesh
Source of Support: None, Conflict of Interest: None
Background: Few Indian studies are available which have examined the risk factors and extracranial and intracranial vascular observations in patients with stroke.
Methods: We prospectively studied the burden of intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS) in patients (n = 300) with acute ischaemic stroke and study the vascular disease to the outcome of the patients.
Results: Their mean age was 57.8 ± 14.2 years; there were 183 (61%) males. The frequency of risk factors were hypertension (73%), diabetes mellitus (46%), tobacco smoking (34%), dyslipidaemia (39.3%), alcoholism (27%), previous stroke (21%), chronic kidney disease (CKD) (9%) and hyperhomocystinaemia (15%). Multiple and single territory infarction was evident in 103 (34.3%) and 197 (65.7%), respectively. Both ICAS and ECAS were evident in 117 (39%), whereas 111 (37%) had ICAS and 36 (12%) had ECAS. On univariate analysis, the presence of CKD (P = 0.01), previous stroke (P = 0.02), ICAS and combined ICAS plus ECAS were associated with unfavourable outcome (P = 0.0001). On multivariable analysis, age >58 years (odds ratio [OR] 1.04, 95% confidence intervals [CI] 0.71–0.89, P < 0.0001), female gender (OR 0.6, 95% CI 0.41–0.87, P = 0.008), National Institutes of Health Stroke Scale score >18 (OR 0.75, 95% CI (0.71–0.80, P < 0.0001) were associated poor functional outcome.
Conclusions: ICAS was more common than ECAS. ICAS and combined ICAS plus ECAS were associated with unfavourable outcome.
Keywords: Atherosclerosis, Intracranial, Extracranial, Ischaemic stroke, Functional outcome
|How to cite this article:|
Vengamma B, Challa SN, Devi B V, Naveen Prasad S V, Pynam P, Reddy R. Assessment of intracranial and extracranial atherosclerosis in patients presenting with acute ischaemic stroke. J Clin Sci Res 2020;9:155-9
|How to cite this URL:|
Vengamma B, Challa SN, Devi B V, Naveen Prasad S V, Pynam P, Reddy R. Assessment of intracranial and extracranial atherosclerosis in patients presenting with acute ischaemic stroke. J Clin Sci Res [serial online] 2020 [cited 2021 Apr 12];9:155-9. Available from: https://www.jcsr.co.in/text.asp?2020/9/3/155/298960
| Introduction|| |
Stroke is the second-most common cause of mortality and a major cause of morbidity worldwide. Atherosclerosis of the major intracranial arteries is an important cause of ischaemic stroke, especially in the blacks, Asians and Hispanics. In the Western world, the major cause of stroke is extracranial carotid stenosis. Sparse data are available which have examined the risk factors and imaging of extracranial and intracranial vasculature in patients presenting with stroke. Presentation and outcomes of ischaemic stroke in developing countries differs significantly from those in developed countries due to wide variations in the aetiological causes and the availability of health-care facilities. This prompted us to undertake the present study at our tertiary care teaching hospital.
| Material and Methods|| |
This was a cross-sectional study conducted at our tertiary care teaching hospital between May 2017 and December 2018. Patients aged over 18 years with acute ischaemic stroke, those within 7 days of symptom onset confirmed by neuroimaging were included in the study. Patients who tested seropositive for human immunodeficiency virus, pregnant women, those with cardioembolic and venous stroke were excluded from the study. A detailed history of all the patients admitted with acute ischaemic stroke was acquired for understanding the aetiology and clinical presentation. In every patient, a thorough clinical examination was done. Patients were investigated according to a fixed protocol, with the aim of delineating the causal mechanism and identifying the risk factors on the pattern practiced in the standard Stroke Data Banks in USA, Europe and South-East Asia.,, Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) Scale at admission in all patients with acute ischaemic stroke. Functional outcome was evaluated using the modified Rankin Scale and unfavourable outcome was defined as a modified Rankin score (mRS) of 3 or more at discharge. Ischaemic stroke subtype was classified as per the trial of ORG 10172 in the acute stroke treatment classification. The laboratory investigations included complete haemogram, blood glucose, serum biochemistry including renal, liver function tests, electrolytes and lipid profile. Imaging investigations included computed tomography (CT) of the head, magnetic resonance angiography (MRA) of the brain, neck vessels, CT angiography (CTA) of brain and neck vessels, Doppler study of carotid and vertebral arteries. Electrocardiogram and two-dimensional echocardiogram were performed in all patients.
Data were recorded on a predesigned pro forma and managed using the Microsoft Excel worksheet (Microsoft Corp, Redmond, WA, USA). All the entries were double checked for any possible error. Descriptive statistics are reported as mean ± standard deviation, median (interquartile range [IQR]). Categorical variables are reported as percentages. Continuous variables were compared using the Student's t-test; categorical variables were compared using the Chi-square test. Multiple logistic regression analysis was undertaken for predicting poor functional outcome. All P values were two-tailed; a P < 0.05 was considered statistically significant. The statistical software IBM SPSS Statistics version 20 (IBM Corp Somers NY, USA) was used for the statistical analysis.
| Results|| |
Three hundred patients were included in this study. Their mean age was 57.8 ± 14.2 years; there were 183 (61%) males. Median (IQR) duration between the onset of symptoms to presentation to hospital was 1.3 (0.8–3.00) days. The median duration of the hospital stay was 10.3 (8–14) days. The frequency of various risk factors found in this study were hypertension in 219 (73%), diabetes mellitus in 137 (46%), tobacco smoking in 102 (34%), dyslipidaemia in 118 (39.3%), alcohol intake in 82 (27%), previous stroke or transient ischemic attack in 64 (21%), chronic kidney disease (CKD) in 26 (9%), hyperhomocystinaemia in 46 (15%), essential thrombocytosis in 19 (6%), polycythaemia in 49 (16%), chronic obstructive pulmonary disease in 5 (2%), peripheral arterial disease in 6 (2%), vasculitis in 6 (2%) and hypothyroidism in 6 (2%) patients. Distribution of number of risk factors is shown in [Figure 1].
|Figure 1: Distribution of number of risk factors in 300 patients with acute ischaemic stroke|
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Majority of the patients presented with right hemiparesis 136 (45%), followed by left hemiparesis in 119 (40%) patients. Broca's aphasia was seen in 45 (15%) patients, Gait ataxia in 43 (14%), Wernickes's aphasia in 41 (14%), global aphasia in 30 (10%), seizures in 20 (7%) and diplopia with ptosis in 13 (4%) patients.
Out of 300 patients, 184 (61.3%) had anterior circulation stroke, 53 (17.7%) had posterior circulation stroke and 63 (21%) had infarcts in both anterior and posterior circulation. One hundred and three (34.3%) patients had multiple territory infarctions and 197 (65.7%) had single territory infarction. Of these, 153 (77.6%) patients had single middle cerebral artery (MCA) territory infarction, 40 (20.3%) patients had posterior cerebral artery infarction and 4 (2%) patients had single anterior cerebral artery territory infarction.
Large artery atherosclerosis (thrombosis/embolus) was seen in 212 (71%) patients, small vessel occlusion in 39 (13%) patients, stroke of other determined aetiology in 32 (10.7%) patients and stroke of undetermined aetiology was seen in 17 (5.6%) patients. Forty-three (14.3%) patients had minor stroke, 120 (40%) had moderate stroke, 58 (19.3%) had moderate-to-severe stroke and 79 (26.3%) had severe stroke. One hundred and seventeen (39%) patients had both intracranial and extracranial atherosclerosis, whereas 111 (37%) patients had intracranial atherosclerosis (ICAS) and 36 (12%) had extracranial atherosclerosis. Thirty-six (12%) patients did not have intracranial or extracranial atherosclerosis.
Extracranial atherosclerosis (ECAS) was more common in males (69.4%), whereas ICAS was more common in females (55%), and this was statistically significant (P < 0.0001 and 0.01 respectively). Common among the younger patients (P = 0.02). Hypertension and diabetes mellitus were more frequent in patients with ICAS than patients with ECAS (73.9% vs. 66.1% and 49.5% vs. 47.2%, respectively). Smoking, dyslipidaemias and alcoholism were more frequent in patients with ECAS than in patients with ICAS (44.4% vs. 37%, 47.2% vs. 39.6% and 41.6% vs. 23.4%, respectively) [Table 1]. Moderate-to-severe and severe stroke was more frequently seen in ICAS (19.8%, 25.2%), both ICAS plus ECAS group (24.8%, 35.9%) than the ECAS group (8.3%, 16.6%) (P = 0.0002).
|Table 1: Comparison of risk factors between intracranial atherosclerosis, extracranial atherosclerosis and combined extracranial atherosclerosis plus intracranial atherosclerosis groups|
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Mean mRS score in 300 ischaemic stroke patients at discharge was 3.3 ± 1.4. On comparing the favourable and unfavourable outcome groups, mean age (P = 0.01) and mean duration of hospital stay (P = 0.001) were significantly higher in unfavourable outcome group. Males had a more unfavourable outcome compared to the female gender (P = 0.0073) [Table 2]. CKD (P = 0.01) and previous history of stroke (P = 0.02) were encountered significantly more frequently in those patients with unfavourable outcome. Stroke due to large artery atherosclerosis was also more frequently seen in the unfavourable outcome group (P = 0.0001). On comparing the two groups, moderate-to-severe and severe strokes were more frequently seen in the unfavourable outcome group than in the favourable outcome group (P < 0.0001). ICAS and combined ICAS plus ECAS were more frequently seen in patients with unfavourable outcome (P = 0.0001).
|Table 2: Comparison of demographic parameters and risk factors between patients with favourable and unfavourable outcomes|
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On multiple logistic regression analysis age >58 years (odds ratio [OR] 1.04, 95% confidence intervals [CI] 0.71–0.89, P < 0.0001), female gender (OR 0.6, 95% CI 0.41–0.87, P = 0.008), NIHSS score >18 (OR 0.75, 95% CI 0.71–0.80, P < 0.0001) were independently associated poor functional outcome.
| Discussion|| |
Stroke is the most common cause of disability; second most common cause of dementia and third most common cause of death in developed world. Like many other serious medical illnesses, stroke has heterogeneous aetiology, caused by modifiable and unmodifiable risk factors. Stroke is becoming an important cause of premature death and disability in low-income and middle-income countries like India.
Large artery atherosclerosis is a common cause for ischaemic stroke secondary to either artery to artery embolization or due to hypoperfusion. Racial differences are seen in the incidence of atherosclerosis. While among the Western population, extracranial atherosclerosis is more common, among African Americans and Asians, ICAS is more prevalent. The reason is not yet understood but genetic factors play a role.,, From different studies, it has been understood that risk factors also slightly vary between ICAS and ECAS. While hypertension and diabetes mellitus are the predictors of ICAS, dyslipidaemias and elderly age are predictors for extracranial atherosclerosis.,
Gender distribution (male:female = 1.5:1) observed in the present study were comparable with previous studies.,,, However, the mean age at the presentation (57.8 ± 14.2 years) in the present study was lower when compared to observations from Western studies.,,, The reason for a decade earlier the mean age of occurrence of stroke in our study is probably attributable to the increased prevalence of traditional risk factors.
In the present study, the most commonly encountered risk factor was hypertension (73%) followed by diabetes mellitus (46%), dyslipidemias (39.3%) and smoking (34%). Similar results were reported in other published studies.,,, In the present study, anterior circulation stroke was more common than posterior circulation stroke (184 [61.3%] vs. 53 [17.7%] patients), whereas infarcts in both territories were seen in 63 (21%) patients. In a study, anterior circulation stroke was seen in 69.8%, posterior circulation stroke in 27.8% and infarcts in both territories were seen in 2.4% patients. We observed similar results. In our study, single territorial involvement was more common than multiterritorial involvement. Among the individual arterial territories, MCA (153 [77.6%] patients) was most commonly involved. This was similar to the studies from India and Asia.,
In our study, large artery atherosclerosis (thrombosis/embolus) was the most common and seen in 212 (71%) patients, small vessel occlusion in 39 (13%) patients, stroke of other determined aetiology in 32 (10.7%) patients and stroke of undetermined aetiology was seen in 17 (5.6%) patients. Similar observations were reported in other studies., In a study, patients with 50%–99% stenosis of the extracranial carotid artery system were excluded from the study. Despite of this, large artery strokes were much higher in that study. However. a high incidence of stroke of undetermined aetiology followed by cardioembolic and large artery atherosclerosis was reported in another study.
We observed that ECAS was significantly more common in males (69.4%), whereas ICAS was significantly more common in females (55%) (P < 0.0001). ICAS was more common among the younger patients (P = 0.02). Hypertension (73.9% vs. 66.1%, P = 0.0001) and diabetes mellitus (49.5% vs. 47.2%, P = 0.0001) were more frequent in patients with ICAS than patients with ECAS. Tobacco smoking (44.4% vs. 37%, P = 0.001), dyslipidaemia (47.2% vs. 39.6%, P = 0.0003) and alcohol usage (41.6% vs. 23.4%, P = 0.0001) were more frequent in patients with ECAS than in patients with ICAS. In another study, female preponderance, hypertension and diabetes mellitus were commonly seen in patients with ICAS, whereas smoking, dyslipidaemias, elderly age and male preponderance were seen with ECAS. In the Northern Manhattan Stroke study, it was observed that patients with diabetes mellitus and metabolic syndrome were more prone to have ICAS. In a study from Japan, it was observed that the independent predictors for ECAS were older age, hyperlipidaemia and ischaemic heart disease, those for ICAS were age, hypertension and diabetes mellitus.
In our study, moderate to severe and severe strokes were more frequently seen in ICAS group (19.8%, 25.2%), both ICAS plus ECAS group (24.8%, 35.9%) than the ECAS group (8.3%, 16.6%) (P = 0.0002). This differed from observations documented in another study, where more severe stroke was seen in patients with ECAS.
In the present study, poor functional outcome (mRS score ≥3 at discharge) was seen in 58.3% patients. On comparing the patients with good and poor functional outcome, elderly age (P = 0.001), male gender (P = 0.007) and longer hospital stay (P = 0.007) were frequently observed in patients with poor functional outcome. CKD (P = 0.01), previous stroke (P = 0.02), large artery occlusion (P = 0.0001) and more severe stroke (P = 0.0001) were more frequently observed in the unfavourable outcome group. Furthermore, ICAS and combined ICAS plus ECAS were more frequently observed in unfavourable outcome group (P = 0.0001). In a study. elderly age, hypertension and severe stroke were predictors of poor outcome. In the Prospective Cohort with Incident Stroke study, diabetes mellitus, elderly age and severe stroke were associated with poor functional outcome. Our observations were similar., On multiple logistic regression analysis, we found older age (P < 0.0001), female gender (P = 0.008) and high-NIHSS score (P < 0.0001) were associated poor functional outcome. Similar results were described in other studies.,
The present study was conducted in a single academic institute. For evaluating intracranial vasculature, instead of digital subtraction angiography, which is the gold standard. CTA and MRA were used.
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Conflicts of interest
There are no conflicts of interest.
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