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Table of Contents
ORIGINAL ARTICLE
Year : 2020  |  Volume : 16  |  Issue : 3  |  Page : 105-109

Prediction of outcomes in stroke patients from radiological findings – A hospital-based retrospective cohort study from a comprehensive stroke care center in Kerala, India


1 Department of Health Sciences Research, Amrita Institute of Medical Sciences, Kochi, Kerala, India
2 Department of Neurology, Amrita Institute of Medical Sciences, Kochi, Kerala, India
3 Department of Community Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India
4 Department of Biostatistics, Amrita Institute of Medical Sciences, Kochi, Kerala, India

Date of Submission17-Feb-2020
Date of Acceptance06-Mar-2020
Date of Web Publication09-Oct-2020

Correspondence Address:
Dr. Vivek Nambiar
Division of Stroke, Centre of Neurosciences, Amrita Institute of Medical Sciences, Ponekkara, Kochi - 682 041, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/AMJM.AMJM_18_20

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  Abstract 


Introduction: Functional outcome after stroke can be improved by early and accurate diagnosis with the help of imaging techniques such as computed tomography (CT) and magnetic resonance imaging. Alberta Stroke Program Early CT Score (ASPECTS) calculated from the CT image infarct areas of middle cerebral artery (MCA) circulation is supposed to be a reliable outcome predictor. Methodology: A retrospective cohort study was conducted in the Comprehensive Stroke Care Center for a period of 6 months. All adult patients (18–90 years) who had visited the hospital from January 2014 to December 2017 were enrolled for the study. Patients with MCA strokes were only included in the study since the ASPECTS is defined for this territory. The data were gathered from the electronic format of the patient information system in the institution and were entered in a structured proforma specifically designed for the study. ASPECTS was calculated from the CT findings of the patient. The modified Rankin Scale (mRS) scores were calculated for every patient at four different time points. The collected data were compiled in a Microsoft Excel sheet and were analyzed using IBM Statistical Package for Social Sciences (SPSS version 21). The summary statistics for categorical variables were reported using frequency and percentage and continuous variables as mean (standard deviation). We reported the association of the ASPECTS with mRS at different time points using the Chi-Square test. Results: A total of 132 adult patients were enrolled in the study. The mean age of the study population was 60.72 (±13.99) years, and among them, 93 (70.45%) were males. Majority of the patients were nonvegetarians (99.92%). The most prevalent risk factor found was hypertension (62.1%). The most common symptom presented by the patients was facial palsy (28%). When the ASPECTS was calculated for 132 patients, 62 patients fell in the high ASPECTS category (8–10), 45 patients had a moderate ASPECTS (5–7), and 25 had low ASPECTS (0–4). mRS scores calculated for four different time points showed a decline in disability in most of the patients. ASPECT and mRS had a negative association signifying, as the ASPECTS increases the number of functional disability decreases. Conclusions: Our study results show that ASPECTS can be a definite outcome predictor in MCA stroke patients.

Keywords: Outcomes, radiological findings, retrospective cohort, stroke


How to cite this article:
Sudevan R, Nambiar V, Arumugam Premalatha PP, Babu SS, Vasudevan A. Prediction of outcomes in stroke patients from radiological findings – A hospital-based retrospective cohort study from a comprehensive stroke care center in Kerala, India. Amrita J Med 2020;16:105-9

How to cite this URL:
Sudevan R, Nambiar V, Arumugam Premalatha PP, Babu SS, Vasudevan A. Prediction of outcomes in stroke patients from radiological findings – A hospital-based retrospective cohort study from a comprehensive stroke care center in Kerala, India. Amrita J Med [serial online] 2020 [cited 2020 Oct 30];16:105-9. Available from: https://www.ajmonline.org.in/text.asp?2020/16/3/105/297550




  Introduction Top


Strokes are focal neurological deficits caused by the stoppage of blood supply to a region of the brain. It is one of the major noncommunicable diseases in the world. It holds the third position among noncommunicable diseases, in terms of the mortality rate in the year 2013.[1]. The incidence of stroke among young adults is around 5%–20%.[2] Young adults represent the working population or rather the productive group, the burden of stroke and addressing the problem becomes essential.

Strokes can be ischemic type or hemorrhagic type. Of these, ischemic stroke is relatively common, having a prevalence rate of about 7.2 million cases among 20–64-year-old people in the year 2013, while hemorrhagic stroke accounted for about 3.7 million cases.[3] As of 2013, the prevalence rates of ischemic stroke in developed and developing countries were 4 million and 3.2 million, respectively.[4] Although developing nations share only 44% of stroke cases, the mortality in these areas is around 81%.[4] Hence, again, it should be seen as an important health issue in the developing world.

The global burden of the stroke study in India says that for the year 2010, the incidence rate of ischemic stroke was 43.45/100,000 people.[3] However, a systematic review by Kamalakannan et al. in the year 2017 shows that the cumulative incidence of stroke ranges from 105 to 152/100,000 persons/year, and the crude prevalence of stroke ranged from 44.29 to 559/100,000 persons in different parts of India during the past decades.[5] In Trivandrum, a district in Kerala, the 28-day case fatality rate was found to be 24.5% for urban and 37.1% for rural populations.[6] Again, this urban-rural divide has to be addressed.

It is well understood that quick diagnosis by identification of the early ischemic changes and faster initiation treatment for strokes enhances the functional outcomes like decline in disability and mortality.[7],[8] Hence, techniques must be developed for faster and accurate diagnosis and accurate outcome prediction. This is where the Alberta Stroke Program Early Computed Tomography (CT) score or simply Alberta Stroke Program Early CT Score (ASPECTS) can come in quite handy. ASPECTS is a reliable outcome predictor only when it is accurately calculated. In ASPECTS grading system, the region of the brain supplied by the middle cerebral artery (MCA) is divided into ten topographic regions, as shown in [Figure 1], which are easily observable on a CT. A completely normal patient will start with a score of 10. Whenever one of these regions become hypoattenuated that shows the signs of early ischemic changes, then a point is decreased. Thus, ASPECTS and interpersonal variability are reduced when the guidelines are strictly adhered.[9],[10] Furthermore, if the ASPECTS is low, then the benefit of the patient from thrombolysis will be less and vice versa.[11] The regions considered in ASPECTS are given in [Figure 1].
Figure 1: Axial noncontrast computed tomography showing ten regions considered in Alberta Stroke Program Early Computed Tomography Score. (a) Section at nuclear level: C: caudate head, LN: Lentiform nucleus, IC: Internal capsule, I: Insular cortex, M1: Anterior MCA cortex, M2: MCA cortex lateral to the insular ribbon, M3: Posterior MCA cortex. (b) Section at supranuclear level: M4, M5, M6: Anterior, lateral, and posterior MCA territories, respectively (approximately 2 cm superior to M1, M2, and M3, respectively)

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The modified Rankin Scale (mRS) is used to assess the functional outcome of the patient. It is the scoring system based on the activity and disability of the patient. Scores run from 0 to 6, with 0 being the best outcome and 6 being death. Through studies, it has been proved to be a reliable outcome predictor.[12],[13] The scoring and interpretation of the mRS score is given in [Table 1].
Table 1: Modified Rankin Scale - scoring and interpretation

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The study aims in delineating the clinical characteristics of the stroke patient and interpreting the association of ASPECTS with the functional outcome of the stroke patients. Studies related to this area are deficient from our setting.


  Methodology Top


A retrospective cohort study was conducted in the Comprehensive Stroke Care Center at Amrita Institute of Medical Sciences, Kochi, for a period of 6 months (January 1, 2018–June 30, 2018). All adult patients (18–90 years) who had visited the hospital from January 2014 to December 2017 were enrolled for the study. Only patients with MCA strokes were included in the study since the ASPECTS is defined for this territory. The patients who had strokes of other territories, hemorrhagic strokes, intracranial bleed; patients with baseline mRS >3; and patients with concomitant carcinomas were excluded from the study.

The data were gathered from the electronic format of the patient information system in the institution and were entered in a structured proforma specifically designed for the study. The proforma included demographic details, dietary habits, other habits such as smoking and alcoholism, risk factors like presence of diabetes mellitus, hypertension, dyslipidemia and history of cardiac disease, past medication history, symptoms at the onset of stroke, intervention and imaging done at local hospital, CT findings such as hyperdense MCA sign, treatment, ASPECT score, and mRS at different time points.

ASPECTS was calculated from the CT findings of the patient. The mRS scores were calculated for every patient at four different points. A pre-morbid mRS describing the functional state of the patient before the stroke, mRS at admission, and follow-up mRS at 2 weeks and 3 months were calculated based on the available data.

The collected data were compiled in a Microsoft Excel sheet and were analyzed using the IBM SPSS Statistics for Windows, version 21 (IBM Corp., Armonk, N.Y., USA ). The summary statistics for categorical variables were reported using frequency and percentage and continuous variables as mean (standard deviation). We reported the association of the ASPECTS with mRS at different time points using the Chi-square test.


  Results Top


Demographics

A total of 132 adult patients who sought treatment from Comprehensive Stroke Care Center, Amrita Institute of Medical Science, Kochi, for ischemic MCA stroke between 2014 and 2017 were enrolled in the study.

The mean age of the study population was 60.72 (±13.99) years, and the median of the study population was 61 years. The patients were between the age range of 18 and 90. Among 132 patients, 93 (70.45%) were males.

Habits/risk factors

Majority of the patients were nonvegetarians (99.92%). The smoking proportion was 11.4% and that of alcohol use was 9.8%.

Modifiable risk factors were found to be hypertension (62.1%) followed by diabetes mellitus (50%) and dyslipidemia (32.6%), the other factors were coronary artery diseases (CADs) (24.2%) and previous stroke (23.5%). Among 132 patients, increased uric acid levels were found to be high in eight patients and five patients had hypothyroidism.

Past medication history

Twenty-eight percent of the study participants were on antiplatelet drugs, of which 81% were on dual antiplatelets, and the rest were on single antiplatelets. Nearly one-fourth of the population was on statins (25.8%) and antihypertensives (26.5%). Out of 132, only six participants were on anticoagulants.

Symptoms

The most common symptom presented by the patients was facial palsy (28%), and the least common was dysphasia. About 13.6% of the patients presented with hemiplegia, 17.4% had aphasia, 9.1% had hemi-aphasia, and 9% of them suffered from loss of consciousness. Out of 132, five patients had ataxia, and seven had a loss of vision.

Interventions in local hospital

Imaging – Out of 132 patients, 36 had done imaging in a local hospital. Majority of them had done only CT (33 patients), and two had done only magnetic resonance imaging (MRI). Only one out of 36 patients had done both MRI and CT.

Thrombolysis

Ten patients had undergone thrombolysis in the total study population, among which the door-to-needle time could be calculated for eight patients. About five patients underwent thrombolysis 4 hours after entering the hospital, and three other patients had a door-to-needle time of 3, 4.5, and 5 hours respectively.

Complications – No other complications such as angioedema and anaphylaxis were reported.

One patient underwent mechanical thrombectomy.

Four patients had hyperdense MCA sign.

Alberta Stroke Program Early Computed Tomography score

When the ASPECTS was calculated for 132 patients, 62 patients fell in the high ASPECTS category (8–10), 45 patients had a moderate ASPECTS (5–7), and 25 had low ASPECTS (0–4).

Modified Rankin Scale

Premorbid modified Rankin Scale

One hundred and thirteen patients had an mRS value, which was within 0–1. In the range of 2–4, there were 17 patients, and the premorbid mRS could not be calculated for two patients.

Modified Rankin Scale at admission

There were 27 patients with mRS ranging from 0 to 1. In the range of 2–4, there were 73 patients. There were 31 patients with mRS value of 5, and mRS value for one patient could not be calculated.

Modified Rankin Scale at 2 weeks

Thirteen patients had mRS values in the range of 0–1. Forty-three patients had mRS values in the range 2–4. There were ten patients with mRS value of 6. mRS value was unavailable for 64 patients.

Modified Rankin Scale after 3 months

Thirteen patients had mRS values between 0 and 1. Forty-nine patients had mRS values between 2 and 4. Eleven patients had mRS value of 6. mRS at 3 months was unavailable for 35 patients.

Association between Alberta Stroke Program Early Computed Tomography Score and modified Rankin Scale

When the association between ASPECTS and mRS was calculated, there was an inverse association with a significant P < 0.05. This shows that as the ASPECTS increases the value of mRS decreases, meaning the lesser, the regions affected (high ASPECTS), the better the outcome and vice versa. Association of ASPECTS with mRS at different time points is given in [Figure 2].
Figure 2: Graph showing the association of Alberta Stroke Program Early Computed Tomography Score with modified Rankin Scale at different time points

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  Discussion Top


The mean age of the study population was 60.72 (±13.99) years, and also the incidence showed a male preponderance. This is in concordance with the “Update on the Global Burden of Ischemic and Hemorrhagic Stroke in 1990–2013: The GBD 2013 Study” conducted by Feigin et al.[14] It must be noted that the mean and median ages of the study population had a difference of less than one, showing that the study population shows a near-normal distribution based on age.

We found that hypertension is one of the significant risk factors for stroke according to our study. Most other studies also quote hypertension as an important and modifiable risk factor.[15],[16],[17] Furthermore, it is essential to control hypertension as a primary and secondary preventive act for stroke prevention. Diabetes is the second major modifiable risk factor in this study. Almost half of the population had diabetes mellitus. Diabetes is generally accompanied by hypertension and dyslipidemia, which in turn, are the major risk factors for stroke.[18],[19] Smoking and alcohol intake seem to be significant risk factors.[15],[17] Some studies mention that light drinking poses a lower risk as opposed to heavy or binge drinking.[19] We also find that CAD and previous stroke may also lead to further strokes. Control of these individual risk factors can help to decrease the incidence rate of stroke.

We can see that ASPECTS and mRS show a significant negative correlation with a P < 0.05. This shows that as the ASPECTS increases the value of mRS decreases, meaning the lesser, the regions affected (high ASPECTS), the better the outcome and vice versa. This result is again in agreement with the various studies conducted in the Western population.[20] Furthermore, as time passes, the functional outcome seems to be better for patients with high ASPECTS than a patient with a low score.


  Conclusion Top


Our study results show that ASPECTS can be a definite outcome predictor in MCA stroke patients.

A widespread distribution was observed while plotting the age of the patients. This shows that stroke affects almost all age groups. According to this study, major modifiable risk factors were identified to be hypertension, diabetes mellitus, and dyslipidemia. Prevention of these factors will help in decreasing the incidence of stroke. The other nonmodifiable risk factors were CAD and previous strokes. It can be seen that the nonmodifiable risk factors are, in turn, caused by the modifiable factors. Hence, control of those modifiable factors is of prime importance.

A proper training on the accurate calculation of ASPECTS may help a doctor to determine the severity of ischemia and predict the functional outcome of the patient at the very early stages of an ischemic stroke.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Krishnamurthi RV, Feigin VL, Forouzanfar MH, Mensah GA, Connor M, Bennett DA, et al. Global and regional burden of first-ever ischaemic and haemorrhagic stroke during 1990-2010: Findings from the Global Burden of Disease Study 2010. Lancet Glob Health 2013;1:e259-81.  Back to cited text no. 3
    
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Krishnamurthi RV, Moran AE, Feigin VL, Barker-Collo S, Norrving B, Mensah GA, et al. Stroke prevalence, mortality and disability-adjusted life years in adults aged 20-64 years in 1990-2013: Data from the Global Burden of Disease 2013 Study. Neuroepidemiology 2015;45:190-202.  Back to cited text no. 4
    
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Pexman JH, Barber PA, Hill MD, Sevick RJ, Demchuk AM, Hudon ME, et al. Use of the Alberta stroke program early CT score (ASPECTS) for assessing CT scans in patients with acute stroke. AJNR Am J Neuroradiol 2001;22:1534-42.  Back to cited text no. 9
    
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