Abstract Number: Esoc2026a1092 ‘Primary Prevention’ of Stroke After Acute Coronary Syndrome: A Prospective Population-Based Study

Background and aims The impact of multi-intervention primary prevention of stroke has proved difficult to assess even in people with vascular risk factors due to poor treatment-adherence on long-term trial follow-up. However, a measure of potential could be estimated from the time-course of stroke incidence on intensive risk factor management after acute coronary syndrome (ACS). Long-term stroke risk should be high due to shared vascular risk factors, but intensive prevention could gradually reduce risk. In the absence of previous studies, we compared the time-course of long-term stroke risk after ACS with age/sex-specific expected rates. Methods In a UK population-based study of all vascular events (2002–2022), post-90-day incident strokes after an incident ACS were identified to 15-years by face-to-face follow-up and multiple other sources. Follow-up period-specific observed vs expected stroke rates (age/sex-adjusted Poisson standardised incidence ratios -SIRs) were derived using contemporaneous underlying population stroke incidence. Results During 23,396 years of follow-up of 2,424 90-day post-ACS survivors there were 167 incident strokes. The incidence exceeded expected up to 2-years (SIR=1.40, 95%CI=1.03-1.87, p=0.028), but progressively reversed (pint<0.001) at 2-5-years (0.86,0.62-1.16, p=0.39), 5-10 years (0.68,0.51-0.89, p=0.005) and 10-15 years (0.50,0.33-0.72, p<0.001). Results were similar after accounting for competing risks of cardiac and other causes of death. Conclusions Post-ACS stroke risk is increased until 2-years, but subsequently reverses to below the population norm, even without adjustment for risk factor burden. Long-term primary prevention of incident stroke could be highly effective in other settings if similarly intensive management could be achieved. Conflict of interest Li zhang. nothing to disclose