Abstract Number: Esoc2026a2109 Early Risk of Stroke After Acute Coronary Syndrome: A Prospective Population-Based Study

Abstract Background and aims Stroke risk is increased in days/weeks after an acute coronary syndrome (ACS), due partly to cardioembolism and complications of interventions, but possibly also to shared pathophysiological triggers, such as infection or inflammation. However, there have been few studies of the magnitude, temporal pattern, or mechanisms of stroke risk acutely after ACS. We aimed to quantify the risk, to determine the observed/expected event rate in relation to background incidence, and to determine underlying mechanisms. Methods In a UK population-based incidence study of all vascular events from 2002-2022, we identified all incident strokes within 90 days after ACS. Expected stroke incidence was calculated using age/sex-specific background rates, and observed-to-expected ratios (standardised incidence ratios, SIRs) were derived assuming a Poisson distribution. Aetiology was assessed using the TOAST system. Results Among 2640 patients with a first ACS, 25 strokes occurred within 90-days, with a cumulative incidence of 1.0% (0.67%-1.46%). Observed incidence substantially exceeded the expected rate (SIR=6.12, 95%CI=3.96–9.03; p0.001). Mechanisms of stroke were haemorrhage associated with thrombolysis or dual antiplatelet treatment (n=2), cardioembolism (n=6), and ischaemic stroke complicating cardiac procedures (n=7), but apparently unrelated cryptogenic or lacunar ischaemic strokes were most frequent (n=10), accounting for about 40% of the excess stroke incidence. Conclusions Stroke risk is markedly elevated in the 90-days after ACS, and is not explained purely by haemorrhage, cardioembolism or procedural complications. The excess of other ischaemic stroke is consistent with shared triggers leading to clustering of events. Conflict of interest Li zhang. nothing to disclose