Non-vitamin K oral anticoagulants (NOACs) differ in important ways from warfarin, and surgeons need to appreciate these differences, researchers said. Surgeons need to understand how they work to minimize the preoperative risk.
The anticoagulant effect of NOAC agents is predictable but not readily measurable in routine clinical practice. Some uncertainties remain surrounding the use of these agents in the perioperative setting. Ongoing prospective studies and randomized clinical trials will provide greater clarity on these management issues shortly.
"NOACS are being increasingly used by surgeons, and they need to understand how they work to minimize preoperative risk (both of bleeding and stroke) to have the best outcomes for their patients," said Dr Atul Verma from the University of Toronto, Canada.
Dr Verma's team reviewed 70 articles involving more than 166,000 patients and identified five key practical issues surrounding the use of NOACs in the perioperative setting:
1. Patient populations for which NOAC use is indicated and contraindicated.
2. The timing of NOAC treatment cessation before invasive interventions.
3. Management of NOAC-treated patients requiring urgent interventions.
4. The need for "bridging".
5. The timing of NOAC treatment's reinitiation after invasive interventions.
NOACs are approved for various thromboembolic indications, including stroke prevention in non-valvular atrial fibrillation (AF), but are contraindicated in valvular AF, mechanical prosthetic heart valves, severe renal or hepatic dysfunction, and pregnancy.
Because of their short half-lives, the drugs need be withheld for only 24 hours, if at all, before procedures deemed to be at low or minimal bleeding risk and for 48 to 72 hours before invasive procedures where the anticipated bleeding risk is intermediate or high.
For patients requiring urgent surgery, no special measures need to be taken if the last NOAC dose was at least 24 hours earlier or if surgery can be delayed by more than 24 hours.
Only for patients requiring urgent surgery while still anticoagulated might NOAC-reversal agents be indicated, the authors note in JAMA Surgery, online April 18. But surgeons need to be aware of the increased risk of thromboembolic events immediately after reversal.
Bridging of anticoagulant therapy with heparin is generally not required, and NOAC therapy can be reinstituted in most patients after 24 hours of adequate hemostasis, the team notes.
"Surgeons need not be afraid of the NOACs," Dr Verma said. "Their ease of use will make our lives easier, since they have a short half-life, clear from the circulation within hours, and are still very effective in preventing stroke and thrombosis in patients with AF or venous thrombosis."