Home > General Cardiology, Journal Club > Journal Club 15 February 2012

Journal Club 15 February 2012


Apixaban versus aspirin in patients with atrial fibrillation and previous stroke or transient ischaemic attack: a predefined subgroup analysis from AVERROES, a randomised trial





Patients with atrial fibrillation at increased of stroke unsuitable for vitamin K antagonists


Apixaban 5 mg bd oral (2.5 mg bd for age >80 years, body mass < 60 kg,  creatinine >1.g mg/dL)


Aspirin 81 to 324 mg per day oral


Primary efficacy end-point: stroke or systemic embolism (1 year)

Primary safety end-point: major bleeding (decrease in HB >2g/dL over 24 hours; transfusion of 2 units or more; bleeding that occurs in critical sites [intracranial, intraspinal, intraocular, pericardial, intra-articular,intra-muscular with compartment syndrome, or retroperitoneal]

Study examines effect of prior TIA/stroke status.


In patients with previous stroke or TIA, ten events of stroke or systemic embolism occurred in the apixaban group (n=390, cumulative hazard 2·39% per year) compared with 33 in the aspirin group (n=374, 9·16% per year; hazard ratio [HR] 0·29, 95% CI 0·15—0·60). In those without previous stroke or TIA, 41 events occurred in the apixaban group (n=2417, 1·68% per year) compared with 80 in the aspirin group (n=2415, 3·06% per year; HR 0·51, 95% CI 0·35—0·74). The p value for interaction of the effects of aspirin and apixaban with previous cerebrovascular events was 0·17. Major bleeding was more frequent in patients with history of stroke or TIA than in patients without (HR 2·88, 95% CI 1·77—4·55) but risk of this event did not differ between treatment groups.

Discussion Summary 

  • Apixaban (similar to dabigatran and rivoraxaban) has been demonstrated to have efficacy in reduction of stroke and system embolism  compared with warfarin. The newer agents appear to have consistently lower rates of intracranial hemorrhage compared to warfarin (not covered in the presented paper: background information).
  • AVERROES provided insights into the risks of aspirin (under-appreciated). The evidence fro efficacy in this context of atrial fibrillation is limited and the magnitude of benefit modest: 20% relative risk reduction
  • Patients with prior TIA or stroke are at higher risk of recurrent stroke or systemic embolism as well as bleeding complications.
  • Although there was insufficient grounds to reject the hypothesis of homogeneity of effect for those with and without prior stroke, the relatively small number of events in the subgroups limit the power to detect differential responses.
  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: