Reducing risk after a minor stroke

Many strokes occur in people who have previously had a transient ischaemic attack (TIA) or minor stroke. Previously, the extent to which these more minor 'warning' events directly precede a major stroke was not fully appreciated. Clinical guidelines recommended that patients be investigated and treated, but suggested that this could be done over four weeks, and delays were often much longer in practice. However, research by Professor Peter Rothwell and his team showed that the risk of a major stroke in the first few hours and day after a TIA or minor stroke had previously been greatly underestimated. In several studies, they found that the risk of a major stroke within 7 days of a minor event was consistently as high as 10%.   The 2007 Department of Health Stroke Strategy and many other national and international guidelines subsequently endorsed Peter Rothwell’s assertion that TIA or minor stroke should therefore be treated as a medical emergency. 

However, to achieve this major change in service provision quickly and efficiently, it was important to do two things. First, it was necessary to identify which of the tens of thousands of people who have a TIA or minor stroke each year are at highest immediate risk of a major stroke and absolutely require emergency assessment.  The researchers therefore developed the ABCD system, a simple clinical tool to identify high risk individuals and prioritise them for treatment.  This system has been widely accepted and was adopted by both the NICE guidelines for stroke (2008) and the Royal College of Physicians guidelines (2012) in the UK and many international guidelines, all of which recommend assessment of high risk individuals with 24 hours.

Second, it was necessary to show that emergency investigation and treatment did actually reduce the early risk of major stroke. The team therefore undertook a further ground breaking study (Emergency use of Existing Preventive Strategies for Stroke  - EXPRESS) in which they showed that urgent assessment and immediate initiation of standard medication did indeed reduce the early risk of major stroke – by 80%.  This strategy was immediately rolled-out across the UK as part of the 2008 National Stroke Strategy and the 2008 NICE guidelines, and is estimated to have prevented 10,000 strokes per year in the UK, saving the NHS £200 million in acute care costs alone.  The global impact, resulting from revised clinical guidelines around the world, will have been much greater.

In a separate study, the team also showed that benefits of a surgical procedure to prevent stroke (carotid endarterectomy to remove partial blockages of the carotid artery in the neck) was also substantially greater if performed urgently after a TIA or minor stroke rather than after several weeks, which was the norm at that time. Guidelines changed immediately and subsequent national audits in the UK have shown that the average wait for carotid surgery decreased from over 3 months in the early 2000s to 15 days in 2010-11.  

The Stroke Prevention Research Unit has recently been awarded the Queen’s Anniversary Prize for Higher Education, the highest form of national recognition that UK higher education institutions can achieve.