Observed Versus Predicted Stroke Risk After Transient Ischemic Attack: A Post Hoc Analysis of a Randomized Clinical...

Area of Science:

• Neurology
• Cardiovascular Medicine

Background:

• The ABCD ² score estimates stroke risk in transient ischemic attack (TIA) patients before treatment.
• Dual antiplatelet therapy (DAPT) is now standard for high-risk TIA, altering post-treatment stroke risk.
• Current risk scores may not accurately reflect stroke risk in patients receiving DAPT.

Purpose of the Study:

• To determine the residual ischemic stroke risk in high-risk TIA patients treated with DAPT.
• To compare actual stroke risk with predictions from the ABCD ² score in the DAPT era.

Main Methods:

• Post hoc analysis of the POINT trial, focusing on high-risk TIA patients treated with DAPT.
• Kaplan-Meier estimates calculated for ischemic stroke risk at 2, 7, and 90 days.
• Risk stratification based on ABCD ² score categories and presence of infarct on imaging.

Main Results:

• Cumulative ischemic stroke risks were 1.3% (2-day), 2.0% (7-day), and 4.1% (90-day), all lower than ABCD ² predictions (5.1%, 7.4%, 11.9%).
• Stroke risk did not vary by ABCD ² category but was higher with acute infarct on imaging (P=0.02).
• Patients with infarct on imaging had a 2-day risk of 3.4%, while those without infarct had a 6-fold lower risk (0.8%).

Conclusions:

• High-risk TIA patients on DAPT exhibit significantly lower early stroke risk than ABCD ² score predicts.
• The absence of acute infarct on neuroimaging is associated with substantially reduced stroke risk.
• Risk assessment for TIA patients on DAPT may require updated models that incorporate neuroimaging findings.