A sub-analysis of data from the ROCKET-AF trial shows that rivaroxaban (Xarelto, Bayer Healthcare) might be better at preventing clot-related strokes in patients with atrial fibrillation while minimising the risk of causing a bleeding stroke. The research was presented at the American Stroke Association’s International Stroke Conference 2012.
The ROCKET-AF trial was conducted in 45 countries at 1,178 sites. The study tested rivaroxaban against warfarin in patients with atrial fibrillation.
Among patients with the most common type of atrial fibrillation, without any history of heart valve damage, those who received rivaroxaban were 34% less likely to experience an intracranial haemorrhage, compared with those on warfarin, the study found.
“We have to be very careful about giving anticoagulants to patients at risk of bleeding into the brain, and therefore need to be able to identify who these patients are,” said Graeme J Hankey, lead author and neurologist at the Royal Perth Hospital and University of Western Australia. “Anticoagulant drugs can prevent ischaemic strokes, but paradoxically, they can cause intracranial bleeding, including haemorrhagic strokes.”
The new study also identified five risk factors, independent of the treatment used, that increased the likelihood that atrial fibrillation patients would suffer intracranial bleeding:
- Blacks had a 4.2-fold increased risk compared to whites; Asians’ increased risk was two-fold. Other races did not have a meaningful higher risk.
- In older people, risk increased by one third for every 10 years of age.
- A prior stroke or transient ischaemic attack (TIA) boosted the risk 51%.
- Decreased levels of serum albumin, a protein that helps keep fluid from leaking out of blood vessels, increased the risk 42% for every decrease in albumin by 0.5 g/l.
- A low platelet count also increased the risk of intracranial bleeding.
ROCKET-AF’s primary finding, reported last year at the American Heart Association’s Scientific Sessions 2010, showed rivaroxaban equal to warfarin in preventing stroke or systemic blood clots in the atrial fibrillation patients. However, rivaroxaban patients had less intracranial bleeding and fatal bleeding. The new research aimed to determine the rate and locations of intracranial bleeding that occurred in ROCKET-AF. None of the study participants had experienced intracranial bleeding at enrolment, but 53% had suffered a prior ischaemic stroke.
After a median follow-up of about two years, researchers found 136 of the 14,264 participants had experienced an intracranial bleed – a low rate overall of about 0.5% per year according to Hankey.
Use of aspirin or a thienopyridine drug was associated with an increased risk of intracranial bleeding during the trial. However, taking rivaroxaban during the trial was associated with a lower risk of intracranial haemorrhage than taking warfarin.
The findings apply only to non-valvular atrial fibrillation patients at moderate or high risk of stroke, such as those enrolled in the ROCKET-AF trial, Hankey said. The validity of these findings in other populations of patients with atrial fibrillation awaits further study.