Stroke is the second leading cause of death worldwide, accounting for about 9% of all deaths. It is the leading cause of neurological disability and in developed countries accounts for more than 4% of direct health care expenditure. The burden of stroke is predicted to increase during the next 20 years because of the ageing population. Whilst effective primary prevention is essential about 30% of strokes occur in individuals with a previous transient ischaemic attack: (TIA) or stroke. Recent prospective studies have shown high early risk of recurrent stroke in the days after TIA or minor stroke. Accurate identification and early treatment of these high risk patients is likely to have substantial benefits for stroke prevention. In this thesis, I aimed to study risk of recurrent stroke after TIA in the hyper-acute phase and the role of current clinical scoring systems for use in the hyperacute phase after TIA, in minor stroke, in posterior circulation TIAs and also for predicting the severity of recurrent events. I have also studied patient behaviour immediately after TIA and minor stroke to determine factors associated with delays to calling for medical attention. I have used data from a large population based study; the Oxford Vascular Study (OXVASC). OXVASC is a prospective, population-based incidence study of vascular disease in all territories in Oxfordshire, UK, which started in 2002 and is ongoing. The study population comprises all 91,106 individuals registered with nine general practices and uses multiple overlapping methods of "hot" and ' cold" pursuit to identify all patients with acute vascular events. The research described in this thesis has resulted in several clinically useful findings. Firstly, I have shown that about half of all recurrent strokes during the seven days after a TIA occur in the first 24 hours, with 6-h, 12-h and 24-h stroke risks of 1.2%, 2.1 % and 5.1 % respectively, and that the 24 hour risk was strongly related to the ABC02 score highlighting this as a reliable risk prediction tool in the hyperacute phase. Second ly, I showed that the ABC02 score was highly predictive of major recurrent stroke and inversely related to risk of recurrent TIA. These findings have implications for policies on hospital admission in patients with high scores and for the advice given to patients with low scores. Thirdly, I demonstrated that the predictive power of the ABC02 score is relatively modest in patients with minor stroke, and neither the Essen Stroke Risk Score (ESRS) nor the Stroke Prognostic Indicator II (SPI-II) predict 9O-day recurrence. Fourthly, I was able to show that the risk of stroke was as high after posterior circulation TIA as carotid TIA and that the ABC02 score was predictive in those patients presenting with posterior circulation TIA. Fifthly, I contributed to a study that showed that in patients presenting with TIA or minor stroke irrespective of age, early initiation of existing treatments in those referred to a daily clinic was associated with an 80% reduction in early recurrent strokes. Finally, I highlighted that about 70% of patients do not correctly recognise their TIA or minor stroke and about 30% delay seeking medical attention for over 24 hours. Higher risk patients lend to contact health services most quickly, but 30% of early recurrent strokes still occur prior to any attempt to do so. ii
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:600159 |
| Date | January 2011 |
| Creators | Chandratheva, Arvind |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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