European Journal of Cardiovascular Medicine

Stroke is one of the most common causes life-threatening neurological diseases which is also the third most common cause of death in affected subjects followed by cancer and heart diseases. Stroke accounts for 1 in every 15 reported deaths in India. In the elderly subjects, population segment with more common incidence of stroke, it contributes as most leading cause of disability that need long term hospitalization.¹

When a physician encounters stroke, it must assess comprehensively its etiology along with estimation of stroke severity and should consider the possibility of recurrence or progression followed by assessing the ways of its reversal or stabilization. Also, investigations must be carried out to help clinicians to subcategorize subjects in three different levels that separate non-strokes from strokes including subdural hematoma and cerebral tumors, separating infarction from hemorrhage and identification of specific pathophysiological subtype of cerebral infarction.²

Most common type of stroke seen in medical practice is anterior circulation stroke, whereas, posterior circulation stroke accounts for only 20% of the encountered strokes. Anterior circulation stroke is seen when internal carotids systems and their branches form the anterior circulation of the brain are affected. Majority parts of the both cerebral hemispheres are supplied by both carotid arteries except for occipital lobes and medial part of the temporal lobes that are supplied by posterior cerebral arteries. The area of brain supplied by the posterior circulation includes medial temporal lobe, brainstem, cerebellum, occipital lobes and thalamus.³

The stroke from both anterior and posterior circulation has many risk factors. Identification of these risk factors can help in stroke prevention and progression. Risk factors of stroke are categorized into modifiable and non-modifiable. Also, identification of clinical profile in anterior and posterior circulation stroke.⁴ The present study was aimed to comparatively assess the risk factors and clinical profile in subjects with Anterior and Posterior circulation ischemic stroke.

The present observational study was aimed to comparatively assess the risk factors and clinical profile in subjects with Anterior and Posterior circulation ischemic stroke. The study was done at Department of Medicine at Netaji Subhash Chandra Bose Medical College & Hospital, Jabalpur (M.P.) The study was done after the clearance was taken by the concerned Institutional Ethical committee. The study subjects were from Department of Neurosurgery of the Institute. Verbal and written informed consent were taken from all the subjects before study participation.

The sample size for the study was calculated as follows: the adequate required sample size is 104 and was estimated using following formula - Sample Size Where N = number of samples r = two group ratio ratio = 1 p = Proportion of population = (P1 + P2) Z1-β = it is the desired power (0.84 for 80% power) Z1- /2 = Critical value and a standard value for the corresponding = 1.96 at 95% CI P1 = First Group Proportion in cases = 60% P2 = Second Group Proportion in cases = 40.8% Then n = 104.

The study was conducted in the Wards & ICU of Department of Medicine, N.S.C.B.M.C.H., Jabalpur (M.P.) The inclusion criteria for the study were subjects aged above 14 years, admitted in General Medicine ward with abrupt onset of a focal neurological deficit of vascular origin (ischemic) and persisted for more than 24 hours. The exclusion criteria for the study were subjects aged less than 14 years, hemorrhagic strokes, venous strokes, head trauma, central nervous system tumors, neuro infection causing weakness, and subdural hemorrhage.

For all the included subjects, detailed history was recorded followed by comprehensive clinical examination in subjects with Transient ischemic stroke (duration less than 24 hr) and Hematological investigations done at N.S.C.B.Medical College, Jabalpur. Data for study subjects was collected using structured schedule (case report form) and entered in Microsoft Excel Sheet.

The data gathered were subjected to statistical evaluation using the chi-square test, Fisher’s exact test, Mann Whitney U test, and SPSS (Statistical Package for the Social Sciences) software version 24.0 (IBM Corp., Armonk. NY, USA) using ANOVA, chi-square test, and student's t-test. The significance level was considered at a p-value of <0.05.

The present observational study was aimed to comparatively assess the risk factors and clinical profile in subjects with Anterior and Posterior circulation ischemic stroke. The study included 208 subjects where 60 had posterior circulation stroke and 148 subjects had anterior circulation stroke. The mean age of anterior and posterior circulation stroke subjects was 60.24±12.04 and 56.3±11.94 years respectively. The age distribution for 20-30, 31-40, 41-50, 51-60, 61-70, 71-80, and 81-90 years was statistically non-significant with p=0.484. Similar non-significant difference was seen in anterior and posterior circulation stroke groups concerning gender, systolic blood pressure, diastolic blood pressure, fasting blood glucose levels, triglycerides, and serum cholesterol levels with p=0.08, 0.194, 0.07, 0.994, 0.164, and 0.601 respectively (Table 1).  

Table 1: Demographic data in two groups of study subjects

It was seen that for symptoms in anterior and posterior circulation stroke groups, swallowing difficulty was comparable in two groups with p=0.08. Similar non-significant was seen for hemisensory loss, altered sensorium, aphasia, seizure, and headache with p=0.574, 0.453, 0.08, 0.474, and 0.05 respectively. However, significantly higher dysarthria, ataxia, and vertigo was seen in subjects with posterior circulation stroke compared to anterior circulation stroke with p=0.004, <0.001, and <0.001 respectively (Table 2).

Table 2: Distribution of symptoms in subjects with anterior and posterior circulation stroke

The study results showed that for distribution of involved brain region in subjects with anterior and posterior circulation stroke, in posterior circulation stroke, cerebellum, medulla, pons, mid brain, and occipital region was involved in 50% (n=30), 3.33% (n=2), 30% (n=18), 3.33% (n=2), and 13.33% (n=8) study subjects respectively. In 148 subjects with anterior circulation stroke, basal ganglia, internal capsule, frontal and parietal, parietal and temporal, temporal, parietal, and frontal region was involved in 16.22% (n=24), 4.05% (n=6), 1.35% (n=2), 44.59% (n=66), 4.05% (n=6), 9.46% (n=14), and 20.27% (n=30) study subjects respectively (Table 3).

Table 3: Distribution of involved brain region in subjects with anterior and posterior circulation stroke

On assessing the risk factors in study subjects with  posterior circulation stroke, coronary artery disease was seen in 20.27% (n=30) and 26.67% (n=16) subjects with anterior and posterior circulation stroke with p=0.474, atrial fibrillation was seen in 4.05% (n=6) and 6.67% (n=4), alcohol intake was positive in 28.38% (n=42) and 16.67% (n=10), diabetes mellitus in 32.43% (n=48) and 33.3% (n=20), systemic hypertension in 62.16% (n=92) and 66.67%v (n=40), and smoking in 35.14% (n=52) and 46.67% (n=28) subjects with anterior and posterior circulation stroke with p=0.623, 0.209, 0.927, 0.664, and 0.271 respectively. However, significantly higher plasma lipid levels were seen in 33.33% (n=20) subjects with posterior circulation stroke compared to 12.16% (n=18) subjects with anterior circulation stroke and p=0.01 (Table 4).

Table 4: Risk factors in subjects with anterior and posterior circulation stroke

The study was conducted in Department of Medicine at Netaji Subhash Chandra Bose Medical College & Hospital, Jabalpur (M.P.). 104 patients above 14 years old admitted in General Medicine ward with abrupt onset of a focal neurological deficit of vascular origin (ischemic) and persisted for more than 24 hours were included in the study. Risk factors and clinical profile in Anterior and Posterior circulation ischemic stroke were assessed.

Most of the other studies have reported that 80% of strokes are ischemic, and 20% of ischemic strokes involve the posterior circulation. The Lausanne Stroke Registry and the Besancon Stroke Registry revealed the relative prevalence of posterior circulation stroke to be 26.7% and 26%, respectively. Hallym Stroke Registry (HSR) showed that posterior circulation stroke was responsible for 39.8% of all ischemic stroke. In the present study, 28.85% stroke involve posterior circulation and 71.15 % stroke involve anterior circulation. In the present study, gender distribution in posterior circulation that 80% were males and 20% were female. Caplan et al⁵-New England Medical Centre, posterior circulation stroke registry document, showed that 58% of patients are male and 42% female. Incidence was more in the male population compared to females was in accordance with other studies as Ma. Cristina L et al⁶ study and R. B. Libman et al. study.⁷

In our study, only 3 patients (10%) were older than 75 years, while in NEMC-PCR, 27.7% of patients were in the age group ranging more than 75 years. Lower life expectancy in the Indian population compared to the Western world (66.46 vs. 78.24 years) could be the explanation for this difference. Rawat et al⁸ reported maximum patients of sroke in the age group 41-70 years with the mean age for males 56.52 years and for females 59.82 years, with a median age of 56.5 years.

In present study, hypertension as a stroke risk factor has greater prevalence in posterior circulation (66.67%) stroke than in anterior circulation stroke (62.6%) with (p=0.666). No significant difference was seen in systolic blood pressure(mmHg)(p value=0.192), diastolic blood pressure(mmHg) (p value=0.069) between anterior and posterior circulation. Mean ± SD of systolic blood pressure(mmHg), diastolic blood pressure(mmHg) in anterior circulation was 138 ± 22.26, 85.22 ± 11.49 respectively and in posterior circulation was 131.27 ± 26.92, 80.33 ± 14.02 respectively with no significant difference between them. Subramanian et al reported hypertension in anterior circulation stroke in 69.4% and hypertension in posterior circulation found in 69.4% The Oxfordshire Community Stroke Project showed no difference among prevalence of hypertension or diabetes mellitus between lacunar and cardio embolic stroke similar to A study by Rochester.

Smoking in 46.67% in posterior circulation stroke and (35.14%) anterior circulation stroke with (p=0.273) which was statistically not significant and was the second most common cause similar to NEMC-PCR and Lee et al⁹ studies Mousavi et al¹⁰ found that smoking as a stroke risk factor mainly by large-artery atherosclerosis. Smoking may also contribute to stroke in the younger population. In study done by Subramanian et al¹¹ El sherif et al¹² smoking as risk factor is more prevalent in posterior circulation stroke as compared to anterior circulation similar to present study.

Hypercholesterolemia prevalence between stroke subtypes has contradictory results in many studies due to reasons that some studies did not include this risk factor. In large artery atherosclerosis, hypercholesterolemia has a high prevalence and is identified as an important risk factor for atherothrombotic stroke. The results of the present study showed hyperlipidemia a significant stroke risk factor and its prevalence higher in posterior circulation stroke (33.33%) than anterior circulation stroke (12.16%) (p=0.001)

For clinical features, the current study initially compared the frequency of neurological deficits between the 2 groups and found a similar distribution among the most common symptoms and signs between PCI and ACI. Second, we assessed the ability of a single neurological deficit to discriminate PCI from ACI, and we observed that despite some symptoms and signs having approximately 100% specificity for diagnosing PCI, symptoms/signs with a higher predictive value had a very low prevalence. These findings emphasize the fact that the clinical manifestations between PCI and ACI have a high degree of similarity.

Vertigo was the most common clinical finding in our study, reported in 53.3% of patients in posterior circulation stroke. Vertigo in posterior circulation stroke is due to the involvement of the vestibular nucleus or its connections. Vertigo is a predominant feature of the lateral medullary syndrome and cerebellar stroke, especially due to PICA and AICA territory involvement. Due to the high density of nuclei and tracts in the brain stem, vertigo is usually accompanied by the involvement of other cranial nerves and or long tracts. It has been reported that isolated episodes of vertigo continuing for more than 3 weeks are almost never caused by vertebra-basilar disease Vertigo, nausea, vomiting, ataxia, dysarthria, nystagmus, cross hemiplegia, and visual field defect was significantly lower in anterior circulation as compared to posterior circulation (p value<0.001).

The present study, within its limitations, concludes that PCS and ACS have similar etiology. Risk factors are also similar for PCS and ACS. The current study initially compared the frequency of neurological deficits between the 2 groups and found a similar distribution among the most common symptoms and signs between PC and AC stroke, we assessed the ability of a single neurological deficit to discriminate PCS from ACS, and we observed that despite some symptoms and signs are specific for diagnosing PCS, symptoms/signs with a higher predictive value had a very low prevalence. These findings emphasize the fact that the clinical manifestations between PC and AC stroke have a high degree of similarity.

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