Ischaemic stroke despite antiplatelet therapy: Causes and outcomes

Area of Science:

• Neurology
• Cardiology
• Public Health

Background:

• Ischaemic stroke remains a significant health concern, even in patients undergoing antiplatelet therapy (APT).
• Understanding the characteristics and outcomes of these 'breakthrough' strokes is crucial for optimizing patient care and prevention strategies.

Purpose of the Study:

• To investigate the frequency, causes, and outcomes of ischaemic stroke occurring in patients despite the use of antiplatelet therapy (APT).
• To determine the association between prior APT use and unfavourable functional outcomes or recurrent ischaemic stroke.

Main Methods:

• A cohort study utilizing data from the Swiss Stroke Registry (01/2014-07/2022) including patients with imaging-confirmed ischaemic stroke.
• Assessment of prior antiplatelet therapy (APT) status, stroke aetiology using the modified TOAST classification, and 3-month outcomes (functional status, recurrent stroke).
• Regression models were employed to analyze the association of prior APT with adverse outcomes.

Main Results:

• Out of 53,352 patients, 33.3% were on APT. Among patients with a history of ischaemic stroke/TIA, 55.2% were on APT.
• The aetiology of ischaemic stroke despite APT was diverse, with cardiac embolism (23.6%) and large artery atherosclerosis (19.8%) being most common.
• Prior APT was not associated with unfavourable functional outcome or death at 3 months, but was linked to a significantly increased risk of recurrent stroke (aOR 1.26, p < 0.001).

Conclusions:

• Approximately one-third of ischaemic strokes occurred in patients on APT, highlighting the limitations of this therapy in certain cases.
• Strokes occurring despite APT have a heterogeneous aetiology and are associated with an elevated risk of subsequent recurrent stroke.
• These findings underscore the need for continued research into stroke prevention and management in patients receiving antiplatelet therapy.