Patients on oral anticoagulant therapy with vitamin K antagonists (AVKs; warfarin and acenocoumarol) and direct oral anticoagulants (DOACs; apixaban, dabigatran, edoxaban and rivaroxaban), are advised to consider discontinuing treatment in anticipation of invasive manoeuvres. Guidelines and expert consensus recommend, in clinical conditions with a high risk of bleeding, to suspend oral anticoagulant treatment with DOACs 2 or 3 days before the procedure, depending on the glomerular filtrate, to suspend warfarin from day -5 and acenocoumarol from day -4, and to introduce heparins from day -3 after discontinuation of AVKs (so-called 'bridging therapy') for manoeuvres with a high risk of bleeding. In manoeuvres with a low bleeding risk it is possible not to suspend the anticoagulant or to reduce its intensity. Obviously, the patient's intrinsic haemorrhagic and thrombotic risk (antiplatelet intake, renal insufficiency, hepatopathy, age, mechanical valve prosthesis, oncological condition, etc.) must also be taken into account in the overall assessment of pre-procedural preparation.
Gastroenterological endoscopic manoeuvres are generally considered to be at low haemorrhagic risk even if biopsy is planned, but are at high haemorrhagic risk if polypectomy or mucosectomy is planned. The most complex problem arises at the time of re-introduction of anticoagulant post-procedure. In fact, studies evaluating this specific aspect are very few and heterogeneous and mostly retrospective. The variables that are associated with an increased risk of bleeding are: the number and site of polypectomies, the diameter of the polyps, and local haemostasis techniques. Late haemorrhages (\>24 hours) are of concern because the patient is generally at home and because, by the time the eschar falls out (varying between 4 and 10 days post-procedure), they have already resumed anticoagulation. However, there are no prospective studies of sufficient number to clarify whether the reintroduction of anticoagulation modifies the haemorrhagic risk, when is the time of greatest risk after the procedure, and which variables associated with the patient and the procedure most modify the haemorrhagic risk.