الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Stroke is a medical emergency that can cause permanent neurological damage, complications, and lead to death. It is the leading cause of adult disability in the United States and Europe and it is the second leading cause of death worldwide.
The cerebrovascular collateral circulation plays a pivotal role in the pathophysiology of cerebral ischemia. Characterization of the collateral circulation with advanced neuroimaging modalities that provide angiographic information and perfusion data elucidates critical determinants of collateral anatomy and blood flow that determines penumbra and tissue fate hence clinical outcome.
The aim of the present work was to assess collateral pathway in the setting of acute ischemic stroke using a newly invented classification/ grading system of collaterals and correlating the severity of the neurological defects (using NIHSS) and the different stroke risk factors with the findings in Digital Subtraction Angiography (DSA).
The study was a prospective one, conducted on 30 patients presenting with acute ischemic cerebrovascular stroke either to Alexandria University Main General Hospital, Tanta University Interventional Neurology Center or to other private hospitals in Alexandria in a 12 month period from April 2011 to March 2012.
All patients underwent diagnostic angiography for one of the following reasons:
a- Endovascular intervention (angioplasty and stenting) as a secondary preventive measure in acute stroke.
b- Endovascular intervention for patients undergoing IA thrombolysis in acute stroke.
c- Patients undergoing diagnostic catheter-based angiography in acute stroke when other non-invasive measures (CTA, MRA, TCD) short-yielded a conclusive data.
Collateral status was assessed according to a newly invented classification/ grading system and was correlated with other parameters including the demographic data, risk factors, different subtypes of stroke, site of occlusion, initial and follow up severity of stroke and relation to outcome.
The study was conducted on 19 Males (63.3 %) and 11 Females (36.7 %) with a mean age 57.73 ± 11.92.
Most of the patients had history of Hypertension; 23 patients (76.7%). Half of the studied patient had history of Diabetes Mellitus; 15 patients (50.0%). TIA was found in 12 patients (40.0%). Hyperlipidemia was found in 17 patients (56.7%). 15 patients of the studied sample (50.0%) were smokers.
On initial assessment of the patients on presentation using NIHSS; 7 patients were classified as Minor (1-4) (23.3%), 19 patients were Moderate (5-12) (63.3%) and 4 patients were Severe (>12) (13.3%).
On follow up assessment upon discharge with the same scale; 4 patients (13.3%) scored 0 (Complete Recovery), 9 patients were Minor (30.0%), 14 patients were Moderate (50.0%) and only 3 patients were Severe (6.7%).
Outcome of the patients was grouped into 3 groups (Improved – Stationary – Worsened) based on assessment of NIHSS upon admission and discharge.
”Improved” or ”Worsened” were defined as: change of stroke severity by 4 points or more using NIHSS. ”Stationary” meant no change of NIHSS status.
It was found that 14 patients (46.7%) showed improvement, 15 (50.0%) patients with a stationary course and only 1 patient (3.3 %) worsened on follow up. Mean period for follow up was 6.93 ± 2.90 day, ranging from (2-15 days).
The studied patients were classified according to TOAST classification of stroke, 26 patients (86.7%) showed ”Large artery athrosclerosis”, 2 patients (6.7%) showed ”Cardioembolism”, 1 patient (3.3%) showed ”Small vessel occlusion” and 1 patient (3.3%) was classified as ”Other determined cause” (giant aneurysm causing ischemic stroke through stealing phenomenon).
Analysis of the collaterals on DSA in the studied group showed 23 patients (76.7%) with Collaterals and 7 patients (23.3%) with No collaterals. Of those 23 patients, one patient (3.3%) had only Externally dependant collaterals, 10 patients (33.3%) had only Internally dependant collaterals and 12 patients (40.0%) had Mixed dependence (both External and Internal).
Further analysis of the group showed that a functioning CoW was present in 14 patients (63.3%) either alone or in Mixed dependence with Leptomeningeal collaterals, and Leptomeningeal collaterals were present in 8 patients (36.4%) either alone or in Mixed dependence with Willisian collaterals.
Robustness of collaterals was assessed in the studied group by different grading parameters in our new scale. We assessed Recruitment of collaterals, Extension of filling, Site of occlusion and Laterality of supply.
In the studied group, 1 patient (3.3%) had a normal angiography with no apparent vessel occlusion. 7 patients (23.1%) had MCA stenosis. 13 patients (43.3%) had ICA stenosis. 1 patient (3.3%) had Basilar artery stenosis. 7 patients (23.1%) had Vertebrobasilar stenosis. 1 patient (3.3%) had ICA giant aneurysm presenting with ischemic infarction through stealing phenomenon.
According to the site of occlusion; 16 patients (53.3%) showed only proximal steno-occlusive lesions, 3 (10.0%) patients showed only distal steno-occlusive lesions and 9 (30.0%) patients showed steno-occlusive lesions at proximal and distal sites. Only 2 (6.6 %) patients showed no occlusion on DSA; one presenting with Giant cerebral aneurysm with steal phenomena and one patient with normal angiographic findings.
Correlative analysis of the studied patients revealed the following:
1- There was no statistically significant difference between gender of the patients and the development of collaterals. There was also no statistically significant difference between the different types of collaterals and sex.
2- There was a statistically significant difference between the age of the studied patients and the development of collaterals and their types; younger patients showed more collaterals than older patients and of more mixed dependence type.
3- There was no statistically significant difference between the different risk factors of stroke and the development of collaterals. There was also no statistically significant difference between the different types of collaterals and the different stroke risk factors.
4- There was a statistically significant difference between collaterals and stroke outcome. Patients with good collaterals had more favorable outcome than those without collaterals. There was no statistically significant difference though between the different types of collaterals and stroke outcome.
5- There was a statistically significant difference between the positive parameters in the newly invented grading scale and favorable outcome. Patients with more than one collateral branch recruited, patients with extension of filling for one or more than one distal branch and patients with bilateral collaterals showed significant improvement of their clinical condition.
6- There was no statistically significant difference between the development of collaterals and the subtypes of TOAST classification of acute ischemic stroke. There was also no statistically significant difference between the different types of collaterals and the different subtypes.
7- There was no statistically significant difference between the site of occlusion and the development of collaterals. There was also no statistically significant difference between the different types of collaterals and the site of occlusion.
8- Studying Leptomeningeal collaterals and Willisian collaterals as distinguished subtypes of collaterals showed no statistically significant difference between them and the other parameters in the study.
In conclusion, our study showed a statistically significant association between age and the development of collaterals as younger patients showed more collateral development when compared to older patients. Our study also showed a statistically significant relation between the presence and robustness of collaterals and favorable clinical outcome while patients with poor outcome showed no or poor collaterals. Patients with more than one collateral branch recruited, extension of filling for one or more than one distal branch and patients with bilateral collaterals showed significant improvement of their clinical condition.