Monitoring strategies for patients treated with the new oral anticoagulants and the need for laboratory evaluation of hemostasis

New oral anticoagulants that directly inhibit Factor IIa (dabigatran) or Factor Xa (rivaroxaban, apixaban) are currently available for prevention of venous thromboembolism (VTE) after orthopedic surgery, treatment of acute VTE, and prevention of arterial thromboembolism in non-valvular atrial fibrillation. These agents offer advantages over vitamin K antagonists including rapid onset, shorter half-lives, fewer drug interactions, and the lack of a need for routine monitoring. The fact that monitoring is not required should not, however, lead to lack of surveillance or a fire and forget medicine approach because there are several medical conditions that require careful clinical surveillance and, sometimes, laboratory monitoring. The main situations that require close monitoring are major bleeding, assessment of compliance (in particular during comorbidities other than vascular disease, e.g. dementia), overdose, sudden or progressive renal dysfunction, extreme body weight, concomitant use of other drugs that may induce impairment of new oral anticoagulants, need for urgent surgery.