Stroke Risk High In Patients Off Anticoagulant Therapy

Stroke Risk High In Patients Off Anticoagulant Therapy

New research shows that patients who discontinue their anticoagulant medication are at increased risk of stroke within a month. Anticoagulant medication is generally prescribed to patients who suffer from heart disease such as atrial fibrillation or patients after myocardial infarction. There are several classes of anticoagulants: heparin and heparin derivatives, fondaparinux, bivalirudin and inhibitor receptors of glycoprotein IIb / IIIa (abciximab, epifibatide).

Anticoagulant medication has many side effects, the most important being bleeding. Therefore, treatment should be adjusted depending on the patient. Also, careful monitoring of patients is necessary to adjust dosage. Another drawback is the intravenous administration or subcutaneous route. For example, high molecular weight heparin should be administered intravenously because bioavailability is small and has a short duration of action. For patients with chronic treatment, such as those with atrial fibrillation oral anticoagulants are used. These are drugs (acenocoumarol, warfarin) that inhibit synthesis of vitamin K dependent clotting factors. Also, patient monitoring is required monthly by measuring the INR (International Normalised Ratio).

Anticoagulants

Anticoagulants work by blood clot dissolution. How they handle the clotting factors differs depending on product. Heparin, for example, acts on factor Xa only when coupled with antithrombin III. Bivalirudin lyses the clot directly, without its action to be conditioned by prior binding of antithrombin III.
Due to the high risk of bleeding, anticoagulant medication should be discontinued before surgery. Manesh Patel, MD, lead author and assistant professor of medicine at the Duke University School of Medicine, said: “Unfortunately, it’s unclear how to provide optimal anti-coagulation coverage during periods of transition”.

Recent studies (clinical trial known as ROCKET AF) showed that rivaroxaban is as effective as warfarin for prevention of embolism. In a study of 14,000 patients, it was found that rivaroxaban, a direct factor Xa inhibitor, can prevent stroke and blood clots as effective as warfarin. Therefore, rivaroxaban was approved by the FDA in 2011 for prophylaxis of deep venous thrombosis in patients undergoing hip and knee replacement surgery and  in patients with atrial fibrillation for stroke prevention. Rivaroxaban has the advantage of allowing predictable anticoagulation, so no need for coagulation monitoring.

However, there were doubts about the increased risk of stroke after stopping anticoagulation with rivaroxaban. It was found however that the risk of stroke and blood clots after rivaroxaban use is the same as for warfarin. In case of temporal interruption of medication, the risks were similar (25.60/100 for rivaroxaban and 23.38/100 patient for warfarin). The risk was greater in the case of transition from rivaroxaban to open label therapy, but was observed only for stroke.