Risk High During Temporary Anticoagulant Halts

Stroke and blood clot risk high when blood thinners are temporarily paused

/ Author:  / Reviewed by: Chris Galloway, M.D.

(RxWiki News) Patients with certain types of atrial fibrillation, a common heart arrhythmia, are at a high risk of stroke and blood clots if they temporarily stop their blood thinning medication before surgery or permanently because of side effects.

Doctors may ask that they stop taking an anticoagulant before an operation or dental procedure because they are at an increased risk of bleeding.

Drugs such as warfarin (Coumadin) or rivaroxaban (Xarelto) lower the risk of blood clots that can lead to a stroke in high risk patients with an irregular heartbeat.

"Don't stop anti-coagulant drugs without doctor approval."

Manesh Patel, MD, lead author and assistant professor of medicine at the Duke University School of Medicine, said that regardless of the drug arrhythmia patients are taking, those who need anti-coagulation revert back to their previous risk of stroke and pulmonary embolism after they stop taking the drug, so the decision should not be made lightly.

Patel said that unfortunately, it's not clear how to ensure optimal blood thinning coverage during transitional periods.

During the review study, researchers analyzed data from the ROCKET AF clinical trial, which found that the risks are similar for patients taking warfarin or rivaroxaban, a newer anti-coagulant taken once daily that doesn't require the constant monitoring of warfarin.

The ROCKET AF trial examined 14,000 patients with atrial fibrillation, finding that rivaroxaban was as effective in preventing stroke and blood clots with no increased risk of bleeding.

However, there were concerns that stopping rivaroxaban could lead to increased rates of stroke and blood clots, and a warning was added to the prescribing information. In response to those concerns investigators examined the results of temporary interruptions of between three and 30 days, or transitioning to warfarin.

They found that stroke and blood clots occurred at a similar rate among both drugs when patients temporarily stopped taking their medication. About six per 100 patient years of those on rivaroxaban as compared to five per 100 patient years taking warfarin experienced a blood clot or stroke after a temporary interruption.

The rate was similar for those who permanently stopped taking medication, at 26 per 100 patient years for rivaroxaban versus 23 per 100 patient years for warfarin.

Patients transitioning from rivaroxaban to open label therapy were more likely to experience a stroke at six per 100 patient years compared to two per 100 patient years in warfarin patients. The risks was comparable for blood clots. However, no difference was found between the two drugs when researchers examined all clot-related events including strokes, heart attack and vascular death within a month of stopping medication.

Though patients taking both drugs were at a high risk if they stopped medication, an end of study transition to warfarin revealed a higher risk of stroke and systemic embolism in patients taking rivaroxaban as compared to warfarin.

The study, funded by the Duke Clinical Research Institute, Johnson & Johnson, and Bayer HealthCare AG, was presented today through the American Heart Association’s Emerging Science Series webinar.

Reviewed by: 
Review Date: 
April 23, 2012
Last Updated:
April 25, 2012