An anticoagulant medicine makes the blood take longer to clot. It plays a vital part in helping to prevent strokes specifically caused by atrial fibrillation (AF), which is a very common heart rhythm disturbance.
AF increases the risk of stroke as it can lead to blood pooling in the heart, which increases the risk of clots forming. If these clots are ejected by the heart, they can block a blood vessel in the brain and cause a stroke.
Warfarin is the most commonly prescribed anticoagulant and, when used appropriately, it’s an effective way of preventing AF-related strokes. But it requires frequent blood tests and careful monitoring.
What are NOACs and who are they recommended for?
The novel oral anticoagulants (NOACs) are a new class of anticoagulant drug. They can be used in the prevention of stroke for people with non-valvular AF, which is when AF is not associated with a problem in a heart valve. They can also be used in the management of venous thromboembolism, which is when a blood clot forms in a vein. Non-valvular AF is the type that most people in the UK have and, like warfarin, NOACs can help to prevent clots from forming in the first place and help protect you from certain types of stroke.
NOACs are more convenient than warfarin in many ways, while having at least equal efficacy and a favourable safety profile.
What procedures need anticoagulation stopped?
Generally minor procedures; including minor ops such as I&D’s and small skin excisions, most dental work (i.e. up to 3 extractions, periodontal surgery), colonoscopies without biopsies, cataracts, etc., don’t require anti-coagulation to be stopped.
If we want to be cautious and reduce bleeding risk further a simple strategy is to perform the procedure at the trough period (first thing in the morning before the next dose) or after 18-24 hours (only a single dose will be missed).
How long should a NOAC be stopped for larger operations?
For larger procedures the NOAC will need to be stopped – the timing depends on the risk of bleeding. These procedures are going to be performed in secondary care so they should be making a decision on cessation and communicating this with the patient.
The following recommendations are taken from the manufacturer’s literature. Each NOAC has slightly different recommendations:
- 1-2 days if creatinine clearance ≥ 50ml / min
- 3-5 days if creatinine clearance ≤ 50ml / min
- Creatinine clearance is irritating for us in primary care as it is not always the same as eGFR – however it is very quick to work out using an online calculator (using age, creatinine and weight)
- 1 day if post-op bleeding risk low
- 2 days if post-op bleeding risk is moderate to high
- 1 day
- 1 day
When can a NOAC be restarted?
For procedures with “no clinically important bleeding risk” NOACs can be started essentially straight away post-op, so patients will reach therapeutic levels in the next few hours.
In other cases a balance must be struck between bleeding and VTE risks. The key is establishing homeostasis (you’d hope this would be done in all cases) then most NOAC manufacturers suggests anticoagulation can be restarted.
Who needs bridging anticoagulation?
This is where low molecular weight heparin is given due to a patient having a high risk of thrombosis or undergoing a procedure which is known to cause thrombosis.
The use of NOACs has the potential to make it easier to avoid longer periods of relative under-anticoagulation and reduce the need for bridging therapy. Moreover, guidelines suggest that most primary care treatments don’t require cessation at all, but performing a procedure during a trough period seems prudent.