Stroke risk high when anti-clotting drugs stopped


Some patients with certain types of atrial fibrillation who are taken off anti-clotting medication face a high risk of stroke or blood clotting within a month, according to new research presented at the American Heart Association’s Emerging Science Series webinar.

“No matter what drug they are on, patients who need anticoagulation revert back to their intrinsic risk of stroke and embolism after discontinuation, so it should not be done lightly,” said Manesh Patel, lead author and assistant professor of medicine at the Duke University School of Medicine, USA. “Unfortunately, it is unclear how to provide optimal anti-coagulation coverage during periods of transition.”

Researchers analysed data from the clinical trial ROCKET-AF, finding the risk is similar whether patients are taking the drug warfarin or the newer anticoagulant rivaroxaban. Rivaroxaban is taken once daily and does not require the frequent monitoring of warfarin, which requires frequent dose-adjustment.

In ROCKET-AF, rivaroxaban was found to be as effective as warfarin in preventing stroke and blood clots in more than 14,000 patients with atrial fibrillation. Patients also had no greater risk of bleeding. However, concerns persisted about possible increased rates of stroke and blood clots after discontinuing rivaroxaban, which led to a warning in the prescribing information.

Because of these concerns, the researchers analysed strokes and blood clots that occurred following temporary interruptions, and between three and 30 days after early drug discontinuation or the transition to warfarin at the study’s end.

Strokes and blood clots occurred:

  • At similar rates with both drugs after a temporary interruption – 6.20/100 patient-years for those on rivaroxaban vs. 5.05/100 patient-years for those taking warfarin;
  • At similar rates in both drugs after permanently stopping the medicines – 25.60/100 patient-years for people taking rivaroxaban (vs. 23.38/100 patient-years for those on warfarin;
  • More often in the transition from rivaroxaban to open label therapy (6.42/100 patient-years) vs. warfarin (1.73/100 patient-years). However, the risk seems to be high only for stroke. There was no difference between the drugs when investigators evaluated all blood clot-related events (including strokes, heart attack and vascular death) within 30 days of stopping medication.

The research is funded by the Duke Clinical Research Institute, Johnson & Johnson, and Bayer HealthCare.