Antiplatelet Flashcards
Does added antiplatelet therapy provide significant benefit to outweigh the potential bleeding risk?
Current guidelines from the American Heart Association (AHA) recommend the use of antiplatelet therapy for secondary stroke prevention. Specifically, these guidelines recommend the use of aspirin, clopidogrel, or aspirin in combination with extended release dipyridamole as the antiplatelets of choice.
When comparing each of these agents individually, the data is inconsistent. The use of dipyridamole and aspirin in combination has demonstrated superior stroke reduction when compared to dipyridamole or aspirin alone.
In contrast, the use of clopidogrel showed no difference in the rate of recurrent stroke when compared to aspirin or the combination of aspirin and dipyridamole.
As a result of these inconsistencies the AHA gives all 3 of these agents a Class IA recommendation for use, indicating that each agent is
MATCH
Management of Atherothrombosis with Clopidogrel in High-risk (MATCH) trial compared the use of aspirin 75 mg daily and clopidogrel 75 mg daily with aspirin 75 mg daily alone for secondary stroke prevention. The study concluded that the addition of aspirin to clopidogrel did not reduce the rate of the primary composite outcome, which included ischemic stroke, myocardial infarction, vascular death, or rehospitalization for acute ischemia. Furthermore, the use of dual antiplatelet therapy with aspirin and clopidogrel was associated with a significant increased rate of life-threatening and major bleeding compared to clopidogrel monotherapy.
SPS3
Secondary Prevention of Small Subcortical Strokes (SPS3) trial was carried out in a similar fashion as the MATCH study, however, it only enrolled patients with lacunar strokes (those arising from small vessel disease). Patients were randomized to clopidogrel 75 mg daily or placebo in conjunction with aspirin 325 mg daily. After a follow-up period of over 3 years, dual antiplatelet therapy failed to provide further ischemic stroke reduction. Additionally, the rate of major hemorrhage was nearly doubled in patients receiving aspirin and clopidogrel.
CHANCE
Clopidogrel in High-Risk Patients with Acute Nondisabling (NIH /= 4).
DAPT better than SAPT. 21-90 days.
POINT
NEJM. 2018.
A combination of clopidogrel plus aspirin reduced major ischemic events, including ischemic stroke (NIH= 4) in the POINT trial.
Benefits outweigh increased bleed risk.
For every 1000 patients on DAPT for 90 days, you prevent 15 combined ischemic events at a cost of only 5 major bleeds.
If DAPT is given for just 30 days, then this results in 19 major ischemic events being prevented per 1000 patients treated at the cost of two extra major bleeds.
Almost all bleeds GI and systemic. Not intracranial.
Navigate ESUS
NEJM. 2018
Rivaroxiban no better than Aspirin in preventing recurrent stroke, and had a higher risk of bleeding.
Over 18 months.
Just a diagnosis of ESUS is NOT enough to justify anticoagulation.
Re-SPECT ESUS.
NEJM. 2019
Dabigatran no better than ASA in preventing recurrent stroke.
Just a diagnosis of ESUS is NOT enough to justify anticoagulation.
CRYSTAL-AF.
AHJ. 2014.
Implanted monitor more sensitive for pickup of AF over longer time than external ambulatory monitors.
5% detected in first 30 days.
21% by one year.
Implante loop recorders detect AF of >2 mins.
External recorders detect AF of > 30 seconds.
What is significant duration of afib.
30 secs? 2 mins? 6 mins. 24 hrs? More?
Brillinta Ticagrelor
JAMA. 12/2021
CVA and TIA. Meta-analysis. N= 22,098 DAPT w/ Ticagrelor v. w/ Plavix Either better than asa monotx. Neither better than other.
THALES
NEJM. 2020
NIH </= 5.
Treat w/loading doses first day.
Brillinta+ASA vs ASA alone.
30-day trial only.
Tx. Group marginally lower stroke recurrence 30-days.
Significantly more “severe” bleeds.
