Comparative Study of Risk Factors Between Lacunar and Non-lacunar Ischemic Strokes

Abstract:
Background: Stroke is a leading cause of mortality and morbidity in both developed as well
as developing countries The risk factors in lacunar stroke differ in comparison to non lacunar
strokes. In this study risk factors of lacunar stroke in comparison to non-lacunar were
evaluated.

Objectives: The aim of the study was to compare the risk factors among lacunar
stroke and non-lacunar stroke.

Methodology: This comparative study conducted in the
department of Medicine and Neurology, Dhaka Medical College Hospital, Dhaka from
September 2010 to August 2011. MRI of brain was done in 151 patients above 18 years of
age with ischemic stroke and Lacunar stroke was found in 31 patients and non-lacunar
stroke was detected in 120 patients. Based on the inclusion and exclusion criteria from
them 30 patients with lacunar stroke were selected as Group-A patients and equal number
of non-lacunar stroke same ages as group B were compared of. The risk factors of stroke
were defined as hypertension, diabetes mellitus, hypercholesterolemia, smoking, history of
transient ischemic attack, myocardial infarction, atrial fibrillation and carotid artery stenosis.

Results: Out of 151 patients with ischemic stroke non-lacunar stroke was predominant,
which was 79.47% and lacunar stroke was 20.52%. The mean age was found 60.9±10.2
years in Group A and 56.2±11.8 years in Group B, which was almost similar between two
groups (p>0.05). Male were predominant, which was 63.33% and 76.67% in lacunar and
non-lacunar stroke respectively. Male and female ratio was 2.3:1. Regarding the risk factors
hypertension was observed most common risk factor among the patients having lacunar
and non-lacunar strokes. Hypertension and diabetes mellitus were common in lacunar stroke
and myocardial infarction, carotid artery stenosis and hypercholesterolemia were common
in non-lacunar stroke which were statistically significant (p<0.05) between the both groups. However, the percentage of smoking, previous TIA and atrial fibrillation were not significantly (p>0.05) different between lacunar and non-lacunar stroke. Conclusion: Hypertension and
diabetes mellitus were common in lacunar stroke, and myocardial infarction, whereas carotid
artery stenosis and hypercholesterolemia were common in non-lacunar stroke and the both
groups were statistically significant (p<0.05) . So modification of risk factors may reduce the
incidence of ischemic stroke

Introduction:
Stroke is a neurological disease, which is major cause of death and disability worldwide. Stroke kills about five million people each year making this the second major cause of death worldwide. At least fifteen million others have non-fatal stroke annually and about a third are disabled as a consequence.

1. The word stroke is used to refer to a clinical syndrome of presumed vascular origin.
2. It is the outward manifestation of a localized sudden interruption of the blood supply to some parts of the brain on etiological basis, of all strokes about 85% are ischemic and 15% are hemorrhagic.
3. In a hospital based study in Bangladesh among stroke patients, it was found that 57.84% were ischemic and 42.16% were haemorrhagic.
4. Ischemic stroke occurs either due to thrombosis or embolism involving the cerebral circulation and categorized as small vessel lesion and large vessel lesion.
5. This distinction can usually be made by means of clinical features and more reliably by CT or MRI scanning.
6. Around 70% of the thrombotic strokes are due to large artery thrombosis and remaining are small infarcts or lacunars infarcts.
7. Lacunar stroke has been regarded as the least severe subtype of ischemic stroke for many years.
8. Symptomatic lacunar stroke was defined as a stroke presenting one of the 5 classic lacunar syndromes (pure motor stroke ,pure sensory stroke, sensorymotor stroke, ataxic hemiparesis, and dysarthria – clumsy hand syndrome) and confirmed by small (<15mm in diameter) subcortical infarct on brain MRI in the absence of any other morphological cause of ischemic stroke found on the neuroimaging examination.
9. These are presumed to result from the occlusion of single, small, perforating arteries supplying the deep subcortical areas of the brain. If the occlusive arterial pathology is distinct from the atherothromboembolic processes that occlude larger arteries, causing most other types of ischemic stroke, the best strategies for the investigation and treatment of patients with lacunar infarction might differ from those for patients with other ischemic stroke subtypes. The arterial pathology of lacunar infarction is based largely on Fisher’s meticulous clinicopathological studies, in which he serially dissected the vascular supply of a total of 68 lacunar infarcts in 18 postmortem brains.
10. To be defined as a lacunar stroke by MRI, the following criteria had to be met: (1) be round or oval in shape; (2) measure <1.5 cm in diameter; (3) be located in the typical territory supplied by deep or superficial small perforating arteries; (4) not be in cortical territories; and (5) not have the morphological and topographical distribution consistent with partial internal border-zone infarcts.
11. Non-lacunar ischemic stroke was defined as either e”2 of the following symptoms: (1) higher cerebral dysfunction (e.g., dysphasia, dyscalculia, visuospatial disorder); (2) homonymous visual field defect; and (3) ipsilateral motor or sensory deficit, or higher cerebral dysfunction alone or a motor or sensory deficit more restricted than those classified as lacunar (e.g., confined to one limb, face, or hand but not the complete arm) and additionally MRI of brain following the event had to show an appropriate cortical, subcortical or combined lesion of > 1.5 cm diameter in the absence of an obvious cardioembolic source.
12. Pathological studies are rare because autopsy rates are declining, lacunar strokes have a low-case fatality rate8 and tracing the vascular supply of subcortical lesions is technically difficult and time consuming 10.Difficulties in imaging the small perforating intracranial arteries has made informative imaging studies scarce. An alternative approach has been to compare the risk factor profiles of patients with lacunar infarcts versus those with non-lacunar infarcts because this may reveal differences suggestive of distinct arterial pathologies. The cause of lacunar infarction is occlusion of a single small penetrating artery. This occlusion may be due to microatheroma and lipohyalinosis, which are associated with hypertension, smoking, and diabetes, or may result from microembolism from the heart or carotid arteries 7,12.Atrial fibrillation and ipsilateral carotid stenosis have a stronger association with non-lacunar infarcts.
    
    

Materials and Methods:
This Observational comparative study was conducted in the department of Medicine and Neurology, Dhaka Medical College Hospital, Dhaka from September 2010 to August 2011. MRI of brain was done in 151 patients above 18 of age years with ischemic stroke and lacunar stroke was found in 31 patients and non-lacunar stroke was detected in 120 patients. Inclusion criteria: were 1) Evidence of lacunar/ non-lacunar infarct by MRI of brain 2) History of first ever ischemic stroke.3) Presenting within two weeks of symptoms. 4) Adult patients Age: 18 years and above Exclusion criteria: 1) MRI of brain not showing a relevant lesion. 2) History of recurrent stroke. 3) Not willing to be included in the study. 4) Age less than 18 years. MRI of brain was done to every patient to confirm the diagnosis lacunar and non-lacunar stroke by ‘AIRIS ²I Hitachi’ MRI machine (0.3 Tesla). MRI of brain of all patients was reviewed by the same consultant radiologist in DMCH blinded to the clinical data and to any hypothesis about this study. Following the above inclusion and exclusion criteria from them 30 patients with lacunar stroke were selected as Group-A patients and equal number of non-lacunar stroke same ages as group B were compared The risk factors of stroke were defined as hypertension; diabetes mellitus ;
hypercholesterolemia ; smoking ; history of transient ischemic attack; myocardial infarction; atrial fibrillation and carotid stenosis Data was collected by face-to-face interview, physical examination and investigations in a data collection sheet.. On admission detailed history and thorough clinical examination including neurological assessment was carried out. Emphasis was given on risk factors especially hypertension and diabetes mellitus. Patients who presented with sudden onset of lateralizing signs especially in the presence of atrial fibrillation, rheumatic heart disease, recent myocardial infarction and carotid bruit were considered to be suffering from ischemic stroke. In addition to routine investigation fasting blood sugar, lipid profile, ECG and in some selected patient echocardiography and Duplex Ultrasound of carotid (extracranial) vessels were done . Study was intended to evaluate risk factors and clinical presentation in lacunar and non-lacunar strokes. Statistical analyses related with this study were performed by use of SPSS 12 package program The comparisons between patients with lacunar and non-lacunar stroke with the Student t test for normally distributed continuous variables and ÷2 tests for dichotomous variables. Test of performance were done to detect the sensitivity,
specificity, positive predictive value, negative