Abstract 59: Presence of Infarct Predicts Recurrence and Efficacy of Dual Antiplatelet Therapy: A Post-Hoc Analysis of the POINT Trial
Kvernland, A; Rostanski, SK; Mac Grory, B; De Havenon, AH; Liberman, A; Kim, AS; Easton, JD; Johnston, SC; Yaghi, S
Published in: Stroke
The combination of aspirin and clopidogrel for 90 days after minor stroke or transient ischemic attack (TIA) reduced the risk of recurrent stroke in the POINT trial. The risk reduction was greater in patients with infarct on CT or MRI compared to those without infarct.
To investigate the effect of DAPT on minor stroke and TIA in the POINT trial based on (1) the presence or absence of infarct attributed to the index event (“index infarct”) and (2) whether the index event was classified as stroke or TIA.
Patients were divided into two groups based on whether they had an “index infarct” or not. Baseline demographics and clinical variables were compared between groups using standard statistical tests. We used univariate and multivariable cox-regression models to determine associations between presence of infarct on imaging and primary and secondary outcomes, and interaction analyses to determine whether the presence of “index infarct” modifies the effect of DAPT on study outcomes. We also explored whether the association of “index-infarct” with primary and secondary outcomes varied by index diagnosis (TIA vs. minor stroke).
Amongst 4881 enrolled in POINT, 4876 patients had data on whether there was an “index-infarct”; 1793 (36.8%) had “index-infarct”. In adjusted cox-regression analyses, the presence of “index infarct” was associated with the primary efficacy outcome (HR 3.02 95% CI 2.34-3.89, p < 0.01) and subsequent ischemic stroke (HR 3.10 95% CI 2.39-4.02, p < 0.01). The effect of DAPT vs. aspirin on primary efficacy outcome was more pronounced in patients with “index infarct” (HR 0.58 95% CI 0.43-0.79, p <0.01) vs. those without (HR 1.16 95% CI 0.79-1.71, p=0.44) (p for interaction = 0.01). In a secondary analysis based on final diagnosis, the effect of “index infarct” on primary outcome was only significant in those with minor stroke at the time of randomization (p for interaction=0.01) but not TIA at the time of randomization (p for interaction=0.36).
In the POINT trial, efficacy of DAPT was greater in patients with infarct on imaging attributed to the index event. Future work should focus on determining clinical factors associated with this group to help identify patients most likely to benefit from acute DAPT.
