Effect of prior antiplatelet therapy on recurrence in patients with acute cerebral ischaemia: data from the triple antiplatelets for reducing dependency after ischaemic stroke (TARDIS) randomised trial

Abstract Background Data regarding management of patients already on an antiplatelet when presenting with an ischaemic stroke or transient ischaemic attack (TIA) are limited. This secondary analysis of the triple antiplatelets for reducing dependency in ischaemic stroke (TARDIS) trial explored clinical outcomes across prior antiplatelet groups. Methods TARDIS was an international prospective-randomised open-label blinded-endpoint trial assessing 30 days of triple vs. guideline antiplatelet therapy in patients with acute ischaemic stroke or TIA. The number of pre-stroke/TIA antiplatelet agents was collected pre-randomisation. The primary outcome was the combined incidence of, and dependency from, any recurrent stroke (using the modified Rankin Scale) or TIA within 90 days analysed using ordinal logistic regression with adjustment for prognostic factors. Baseline imaging features of brain frailty were adjudicated centrally by neuroimaging experts. Results 1080/3096 (34.9%) participants were on an antiplatelet agent prior to their stroke/TIA and were older, more likely to be male, had more co-morbidities and dependency, and more baseline imaging features of brain frailty than those not on prior antiplatelets. They had a higher incidence of, and dependency from, recurrent stroke or TIA at day 90: 86 (8%) vs. 112 (5.6%), adjusted common OR 1.40, 95%CI 1.02–1.92, p = 0.036; the result was neutralised when adjusted for brain frailty. Randomisation to triple vs. guideline therapy did not influence this effect. Conclusions Participants taking prior antiplatelets were frailer and had a higher incidence and severity of recurrent stroke or TIA at 90 days compared with those not on prior antiplatelets prior to adjustment for brain frailty. Trial registration ISRCTN47823388.