From the Guidelines
Being on 21 days of dual antiplatelet therapy (DAPT) for acute stroke, 10 years out from a spontaneous coronary artery dissection (SCAD) event, is generally considered reasonable, as the acute stroke risk reduction outweighs concerns related to the past SCAD, but individualized assessment is crucial to balance the benefits against the increased bleeding risk. The main concern with DAPT is an increased risk of bleeding, which must be weighed against the benefits of stroke prevention. According to the 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack 1, DAPT is more effective than single antiplatelet therapy (SAPT) for the reduction of recurrent ischemic stroke when initiated soon after high-risk TIA or minor stroke and continued for 21 to 90 days.
The Canadian Stroke Best Practice Recommendations for acute stroke management also support the use of DAPT for a duration of 21–30 days in very high-risk TIA patients or minor stroke of noncardioembolic origin, followed by antiplatelet monotherapy 1. The theoretical risks associated with DAPT include:
- Gastrointestinal bleeding
- Intracranial hemorrhage
- Bruising/minor bleeding These risks must be considered and weighed against the potential benefits of DAPT, particularly in patients with a history of SCAD, although the event occurred 10 years prior.
Given the remote history of SCAD, the short-term DAPT regimen is generally considered reasonable, but it is essential to individualize the assessment, considering factors like other bleeding risks, medications, and comorbidities. After completing the 21-day DAPT course, transition to a single antiplatelet agent (typically aspirin or clopidogrel alone) for long-term secondary prevention is recommended. This approach represents a compromise between maximizing early stroke prevention and limiting the duration of increased bleeding risk, as supported by the 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack 1.
From the Research
Theoretical Risks of Dual Antiplatelet Therapy
Theoretical risks associated with being on 21 days of dual antiplatelet therapy for acute stroke, 10 years out from a SCAD event, include:
- Increased risk of severe or moderate bleeding, as seen in studies where DAPT treatment duration was over 21 days 2
- Potential for recurrent stroke or major cardiovascular events, as highlighted in long-term follow-up studies of SCAD patients 3, 4
- Interaction between antiplatelet therapy and genetic polymorphisms, which may affect the effectiveness of certain medications, such as clopidogrel 5, 6
Bleeding Risks
Bleeding risks are a significant concern with dual antiplatelet therapy, particularly with prolonged treatment durations:
- A study found that DAPT therapy started within 24 hours of symptom onset reduced the risk of stroke recurrence, but was associated with an increased risk of severe or moderate bleeding, particularly with treatment durations over 21 days 2
- The risk of bleeding may be higher with certain medications, such as ticagrelor, compared to others, like clopidogrel 2, 5
Recurrent Stroke and Cardiovascular Events
The risk of recurrent stroke or major cardiovascular events is a concern for patients with a history of SCAD:
- Long-term follow-up studies have shown that SCAD patients are at risk for recurrent dissection and major cardiovascular events, even years after the initial event 3, 4
- The use of antiplatelet therapy, including dual antiplatelet therapy, may help reduce this risk, but the optimal duration of treatment is unclear 6
Genetic Polymorphisms
Genetic polymorphisms may play a role in determining the effectiveness of certain antiplatelet medications:
- Studies have suggested that genetic polymorphisms may affect the response to clopidogrel, and that alternative medications, such as ticagrelor, may be more effective in certain patients 5, 6
- Further research is needed to fully understand the impact of genetic polymorphisms on antiplatelet therapy and to determine the optimal treatment approach for individual patients.