What do the IST-3 results mean for the elderly patient with acute stroke?

1. What do the IST-3 results mean for the elderly patient with acute stroke? Westmead Hospital Clinical School | George Institute for Global Health Richard I Lindley | Professor

2. Potential Financial Conflicts of Interest • I have received payment from Boehringer Ingelheim in my role as member of the Scientific Committee, and speaker for the Australian “Hearts and Minds” meeting • I am on no Advisory Boards • I have no shares in medical or pharmaceutical companies

3. Treatment of the Elderly Patient with Acute Stroke Content • The epidemiology of stroke and old age • Treatment effects seen in IST-3 • Treatment effects in elderly people • Implications for stroke services

4. The epidemiology of stroke and old age Risk factors in stroke patients in Oxfordshire Rothwell et al Lancet 2004; 363: 1925-33

5. Framingham: Risk factors (%) amongst men at age 65 years Carandang et al JAMA 2006; 296: 2939-46

6. Observed changes in stroke incidence in Oxford • Up to a 40% reduction in the age-specific incidence of stroke • Likely due to major reductions in population blood pressure, cholesterol and smoking

7. Implications for future stroke incidence • Stroke will increasingly occur in frail people • Stroke subtypes will change reflecting the changing underlying population risks, the most important being AF • AF causes severe stroke (TACI and PACI ischaemic stroke subtypes)

8. Some Recent Australian Data Incidence study from Western Suburbs of Adelaide • Population of 148,000 • 318 Stroke events (258 ischaemic) • 109 cardioembolic (92 AF) • Third of ischaemic stroke largely preventable Leyden et al Stroke Society of Australasia International Journal of Stroke 2011; 6 (Suppl 1): 21

9. IST-3 Key Design Features • No upper age limit • Patients were functionally independent prior to stroke • Common co-morbidities were not contraindications therefore patients with prior stroke and diabetes were included (provided they were independent) • CT/MRI required to exclude intracranial haemorrhage • Randomisation and treatment to commence < 6 hours from stroke onset • Treatment considered promising but unproven • Informed consent obtained

10. Consumer involvement in IST-3: Consent issues • Most (98%) older people would accept a risk of death if a disabling stroke could be avoided using thrombolysis treatment • “At my age I’d rather take a risk in the hope of retaining my independence” • Consumers advised us to quote the natural history of stroke such as “half of all survivors are disabled and many die from the stroke” • Consumers wanted to know the hard facts about potential risks such as the possible 4% (or 1 in 25) risk of fatal intracranial haemorrhage due to rt-PA Koops and Lindley BMJ 2002; 325: 415-7 Focus group and surveys amongst older people led to clear advice for IST-3

11. Natural History of Ischaemic Stroke Observed in IST-3 Patients Aged > 80 years old

12. IST-3 Results

13. Baseline characteristics: number of patients aged > 80 in each time window

14. IST-3 Consistent with Observational Data • Retrospective analysis of patients undergoing thrombolysis and registered in the Safe Implementation of Treatment in Stroke – International Stroke Thrombolysis Registry (SITS-ISTR) and controls who had not had thrombolysis within the Virtual International Stroke Trials Archive (VISTA) • Odds of favourable outcome: • < 80 years 1.6 (1.5 to 1.7), n = 25 789 • > 80 years 1.4 (1.3 to 1.6), n = 3439 Mishra et al Thrombolysis in very elderly people BMJ 2010; 341:c6046

15. Treatment effects in old age IST-3 Results Consistent with other Common Treatments • Treatment directions rarely change direction with increasing age i.e. treatments that are beneficial in younger people are generally beneficial in older people • Relative risk reductions with effective treatments generally attenuate with increasing age and frailty as other comorbidities increase risks and reduce benefits • Absolute risk reductions can increase in old age as older people are at greater risks of poor outcome than younger people

16. Proportional effects of fibrinolytic therapy for MI on mortality during days 0-35 subdivided by age

17. Implications for Stroke Services and Research Service Redesign • Upper age limits for stroke thrombolysis should be removed • Poor prognosis of severe stroke (particularly AF related large vessel occlusion) without acute intervention should be considered • Consent discussion should include potential benefits and risks • Continued efforts need to be made to decrease onset to needle time, particularly for older people • Future trial design should consider more detailed estimation of premorbid functional abilities and frailty rather than impose an arbitrary upper age limit De Vries et al Outcome instruments to measure frailty: A systematic review Ageing Research Reviews 2011; 10: 104-114 Lindley J Gerontol A Biol Sci Med Sci 2012; 67: 152-7

18. Conclusions • IST-3 should lead to wider implementation of thrombolysis for older people • Health service redesign will be required to implement results in many countries • IST-3 and associated studies will help provide essential information to guide acute stroke physicians in appropriate selection and consent discussions with older people and their families • Future research should avoid upper age limits