RELATIONSHIP BETWEEN RED CELL DISTRIBUTION WIDTH AND CLINICAL STROKE SCORING SYSTEMS IN ACUTE ISCHEMIC STROKE

Yogitha C 1 and Anil Kumar. S 2 . 1. Associate Professor, Department Of General Medicine, KIMS Hospital and Research Centre, Bangalore-04, Karnataka, India. 2. Junior Resident, Department Of General Medicine, KIMS Hospital and Research Centre, Bangalore04, Karnataka, India. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 08 January 2019 Final Accepted: 10 February 2019 Published: March 2019

Red cell distribution width (RDW) is a haematological parameter routinely obtained as a part of Complete blood count. Recently RDW has emerged as a potential independent predictor of clinical outcome in patients with established cardiovascular disease. However, little is known about the role of RDW as a predictor of severity among persons with ischemic stroke. In disorders other than anaemia, the prognostic importance of high RDW levels previously received insufficient attention because of lack of knowledge. However, high RDW levels are associated with a poor prognosis in certain disorders such as acute Myocardial Infarction, stroke and peripheral artery disease . 1 .Inflammation may contribute to morphologic changes in red cells by changing membrane glycoproteins and ion channels. Chronic inflammation, oxidative stress and neurohumeral activation may contribute to the development of atherosclerosis. Hence elevated RDW may be a useful parameter to follow the development of atherosclerosis and hence stroke.

Statistical analysis:-
The collective data as well as the proportion and percentages of variables projected by appropriate charts, tables and graphs. Descriptive and inferential statistical analysis has been carried out in the present study. Results on continuous measurements are presented on Mean SD (Min-Max) and results on categorical measurements are presented in Number (%). Significance is assessed at 5% level of significance. Student t test has been used to find the significance of study parameters on continuous scale between two groups. More than 2 groups were analysed using ANOVA and analysis was done using SPSS statistical software ver 10.0.

Results:-
During the study period from November 2015 to September 2017, those who met the inclusion and exclusion criteria were included in the study.
A total of 100 subjects were studied. The majority of subjects were male (63%). The cases of stroke were common in the age 5 th -7 th decade, making 51% of it. Hypertension was present in majority of the cases i.e, 69%, and the next common risk factor was diabetes mellitus in 51% and smoking 33%. In our study it was found that Right Hemiparesis was the most common neurological deficit at admission (29%) and Left sided weakness was the second most common neurological deficit (25%). 4% of the patients were in a state of altered sensorium. Our study also 358 showed that Left MCA territory was the most common vascular territory involved (34%) with Right MCA being the second most common arterial territory involved (31%). In our study, the effect of RDW on stroke severity was moderate.   In the present study, RDW and the outcome of the patients were found to be statistically significant and RDW correlated well with the mortality of the patients.
Clinically, the severity of stroke is evaluated by several bedside scoring systems or imaging studies. Kara et al 1 studied the RDW in 128 patients with acute ischaemic stroke (AIS; symptoms <24 hours) and compared their scoring systems to the levels of RDW. They have found that significantly higher levels of RDW could predict increased risk of total stroke occurrence with the bedside scoring systems.
Therefore, it is likely that RDW could predict the severity and functional outcomes in patients with stroke.
This study confirmed that RDW played an important role in the progression of an ischaemic stroke.
In the current study, patients did not have atrial fibrillation, 71% of patients had normal ECG with 76% of patients also having a normal echo. 10% had LVH with strain. 16% of patients had Concentric LVH in echo and 8% of patients had Diastolic dysfunction on 2D Echo. However, the cardiac findings neither correlated with the RDW nor with the severity of stroke.
Identification of additional prognostic markers of clinical outcomes among individuals with or at risk of stroke, especially if they can be readily, routinely and cheaply obtained, would be welcome. 359

Discussion:-
The median RDW values were significantly greater in patients who had more severe rather than milder strokes rated with all three scoring systems (GCS, CNS, and NIHSS) . The median RDW values were significantly greater for patients who have had moderate rather than mild stroke rated by CNS and for patients who have had severe rather than mild stroke rated by GCS and NIHSS.
Inflammation is important in the development of ischemic stroke, atherosclerosis, and ischemia. As a marker of inflammation, RDW is correlated with other inflammatory markers such as CRP 2 . Inflammation may affect bone marrow function and iron metabolism. The inflammatory cytokines may cause elevated RDW levels by inhibiting red cell maturation and enabling the release of new and large reticulocytes to the circulation 3 . Therefore, high RDW is an integrated risk factor for conditions of general suboptimal health associated with lower systemic corrective maintenance, recovery, and defense capacity. High oxidative stress may prolong the survival of red blood cells, increase the premature release of large red blood cells into the peripheral circulation, and cause elevation in RDW 1 . Furthermore, inflammation may contribute to morphologic changes in red blood cells by changing membrane glycoproteins and ion channels. Chronic inflammation, oxidative stress, and neurohumoral activation may contribute to the development of atherosclerosis, and elevated RDW may be useful as a simple parameter to follow the development of atherosclerosis.
A short time from onset of complaints to presentation to the hospital is important for attempts to obtain effective reperfusion in patients who have had ischemic stroke. A major problem in these patients is the delay in diagnosis with clinical examination and imaging methods such as CT and magnetic resonance imaging. Therefore, a rapid blood test would be useful for the diagnosis of ischemic stroke. The optimal blood test would support the clinical findings and imaging results and provide information about cerebral damage 4 .
In addition, the test should be simple, rapid, inexpensive, and performed at the bedside. A specific blood marker that could be determined in the early stage of stroke in small hospitals would be useful to screen patients who may require further evaluation for diagnosis and treatment under emergency situations because of the risk of permanent neurological injury.
As such potentially RDW may have great clinical utility as a prognosticator 5 . However, clarifying the precise pathophysiologic mechanism underlying the clinical observations noted in our study is challenging. Several hypothetical explanations have been suggested to explain what now appears to be a consistent impact of higher RDW on adverse outcomes in patients with various types of vascular disease, and other general medical conditions. So for instance, RDW is frequently higher in situations of impaired red cell generation like iron, vitamin B12 deficiency, or folate deficiency, among others, suggesting that higher RDW may be an integrated risk factor for overall sub-optimal health status indicating diminished capacity for systemic repair, recovery and defence 6 .
Another prevailing theory is that elevated RDW may be indicative of rapid red blood cell demise in the context of an underlying inflammatory state. This may be an attractive hypothesis since atherosclerosis, the main culprit behind the majority of stroke and myocardial infarction occurrences, is in part an inflammatory condition 7-8 .

Conclusion:-
In conclusion, the present study showed that RDW, a routinely used, simple and inexpensive test, potentially is an important parameter for predicting the severity of stroke and may predict prognosis. We used GCS, CNS, and NIHSS to determine stroke severity and observed that increased stroke severity and increased in hospital mortality 360 was associated with higher RDW. Therefore, RDW is a good predictor for stroke severity. More systematic studies with good power and precise scientific methodology are required to evaluate the association between ischemic stroke and hematologic parameters, assess the pathophysiology, and confirm the validity of the present results.
Limitations of the present study include the relatively small number of patients. In addition, RDW was measured only once, and RDW may change during the course of the patient in the hospital. Therefore, we could not evaluate fluctuations in RDW and variations in RDW with time.
In summary, the present study showed that RDW, a widely used and inexpensive test, potentially is an important parameter for the diagnosis of stroke and may predict prognosis. We used GCS, CNS, and NIHSS to determine stroke severity and observed that increased stroke severity was associated with higher RDW. Therefore, RDW is a strong predictor for stroke severity. More studies are required to evaluate the association between ischemic stroke and hematologic parameters, assess the pathophysiology, and confirm the validity of the present results.