Periprocedural anticoagulation planning is essential when planning an interventional procedure so that the best balance between the risk of bleeding and thrombosis can be achieved.
The following must be considered in assessment of periprocedural anticoagulation:
bleeding risks associated with the procedure
medications the patient is taking that alter coagulation or platelet function
the patient's underlying thromboembolic risk
When deciding how to best manage periprocedural coagulation it is important to first consult:
the interventional radiologist who will be performing the procedure
departmental or health service guidelines
cardiology – if the patient has had previous PCI, mechanical cardiac valves or has high-risk atrial fibrillation
haematologist – advice with specific thrombophilias, coagulopathies or regarding the reversal of anticoagulants
This article should act as a general guide and not supersede department guidelines or treating physician's preferences.
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Procedural bleeding risk
The risk and consequences of bleeding associated with a procedure can be grouped into three levels of risk:
Low risk
PICC placement
drainage catheter exchange
central line removal
IVC filter placement
superficial aspiration or biopsy
joint injection or aspiration
thyroid biopsy
Moderate risk
facet joint block
radiofrequency ablation
gastrostomy tube insertion
angiography
venous interventions
intra-abdominal, thoracic wall or retroperitoneal abscess drainage
High risk
biliary interventions involving a new tract
complex radiofrequency ablation
nephrostomy placement
Procedural screening
Coagulation screening may be useful in selective cases in recognising and correcting underlying abnormalities. When to perform preprocedural coagulation screening:
possible underlying coagulopathies (previously unexplained haemorrhage, renal disease, liver disease, haematological disease)
to ensure adequate reversal once anticoagulants are stopped (only available for some anticoagulants)
high risk - INR, aPTT, platelet count and haematocrit
moderate risk - INR routinely recommended
low risk - no testing is routinely recommended
Aims for coagulation parameters:
low risk: INR <2.0, transfuse platelets if <50,000/μL
moderate risk: INR <1.5, APTT <1.5 x control, transfuse platelets if <50,000/μL
high risk: INR <1.5, APTT <1.5 x control, transfuse platelets if <50,000/μL
Antiplatelet therapy
Aspirin
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when to withhold: high risk procedures
can generally be continued for low and moderate risk procedures
how long to withhold: 5 days
when to restart: 24 hours
the only way to expedite the reversal of aspirin is with a platelet transfusion or desmopressin
ADP inhibitors (clopidogrel, ticagrelor, ticlopidine, prasugrel)
when to withhold: for low, moderate and high risk procedures. Some may choose to continue for low risk procedures, especially if high risk associated with stopping (i.e. drug eluding stent)
how long to withhold: 5 days is usually sufficient. For high risk procedures it may be appropriate to withhold for 7 days
prasugrel has a greater effect on platelet inhibition and should be withheld for 7 days
when to restart: 24-48 hours depending on bleeding risk
NSAIDS
how long to withhold: generally only high risk procedures
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the time these must be withheld depends on the half-life of the agents
short half-life NSAIDS (e.g. diclofenac, ibuprofen and meloxicam) for 24 hours
medium half-life NSAIDS (e.g. naproxen, celecoxib) for 2-3 days
long half-life NSAIDS (e.g. meloxicam) for 10 days
when to restart: 24 hours
Cardiac stents and withholding antiplatelet therapy
Ceasing antiplatelet therapy in patients who have underwent percutaneous cardiac intervention can increase the risk of stent thrombosis. The most important factors to consider are the type of stent used and the time since percutaneous cardiac intervention.
If possible do not interrupt dual antiplatelet for
at least 6 weeks, and ideally 3 months, following bare metal stent
6-12 months following the placement of a drug eluting stent
It is always useful seek cardiology opinion when considering temporary cessation of antiplatelet therapy in these patients.
Anticoagulant therapy
Warfarin
warfarin is a vitamin K antagonist that has reduced in use since the addition of DOACs, but is still used in patients with prosthetic mechanical valves, venous thromboembolic disease and atrial fibrillation
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how long to withhold:
for low bleeding risk withhold for 3-5 days aim INR <2.0
for moderate to high bleeding risk withhold for 5 days and aim for INR <1.5
if an INR must be reversed faster then is would naturally drop by withholding warfarin – vitamin K, fresh frozen plasma or Prothrombinex may be used
when to restart: 12-24 hours
as the patient level of anticoagulation will be subtheraputic for an extended period they may require bridging anticoagulation – see below
Directly acting oral anticoagulants (DOACs)
when to withhold: moderate and high risk procedures
the DOACs are renally-excreted and thus renal function is important to consider
all can be restarted in 24-48 hours depending on the post procedural bleeding risk
unlike warfarin, the DOACs act directly on the coagulation cascade and therefore patients reach therapeutic coagulation much more rapidly
bridging is almost never required with these medications. The only situations where it could be of benefit is in high thromboembolic risk scenarios in patients unable to take oral medications
there is no reliable way of monitoring reversal of anticoagulation with direct acting anticoagulants. A normal or slightly elevated aPTT (dabigatran) or antifactor Xa activity (rivaroxaban, apixaban) is reassuring. INR is not a reliable measure
Rivaroxaban (Xeralto)
withhold for 3-4 days
5 days in CKD stage 3
7 days in CKD stage 4
Apixaban (Elquis)
withhold 3-4 days
if renal disease present ≥5 days
Dabigatran (Pradaxa)
withhold 4-5 days
if renal disease present 6-7 days
Low molecular weight heparin
administered subcutaneously at either prophylactic or therapeutic doses
the activity can be measured using the anti-factor Xa assay. The aPTT is not a reliable measure if its effect
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prophylactic dose:
low-risk procedures do not require ceasing
moderate to high-risk procedures require withholding from 12-24 hours and 24 hours until the LMWH is restarted
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therapeutic dose:
low-risk procedures require 12-24 hours withholding and restarting at 6 hours
moderate to high-risk procedures require withholding for 24 hours and recommencing at 24-48 hours
Unfractionated heparin
Intravenous (therapeutic)
when to withhold: low, moderate and high-risk procedures
time to withhold: 4 hours
the reversal can be measured with the patients aPTT. Aim for <1.5 x control
rapid reversal of heparin is achievable with IV protamine
when to restart: 6-48 hours depending on bleeding risk
Subcutaneous (prophylactic)
this is usually administered subcutaneously as a prophylactic anticoagulant (5000U every 8-12 hours)
when to withhold: moderate and high risk procedures
time to withhold: 12-24 hours
when to restart: 24 hours
Bridging anticoagulation
the aim of bridging is to minimise the time someone is not anticoagulated periprocedurally
bridging therapy is sometimes warranted in patients taking warfarin, due to slow reversal and anticoagulation. It is generally commenced once the INR is below the therapeutic level (2-3 days after ceasing) and stopped once the INR returns to a therapeutic level
patients on DOACs generally do not require bridging as they have a rapid onset of anticoagulation
bridging is usually achieved with a therapeutic dosing of LMWH or UFH but may be done at prophylactic doses or in-between depending on risk
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the patients who generally require bridging are:
this with mechanical heart valves
high risk atrial fibrillation – CHADS2 5-6
VTE within 3 months or severe thrombophilia
recent coronary artery stenting – seek cardiology opinion
studies such as the BRIDGE trial and PERIOP2 trial have cast doubt on the efficacy of bridging anticoagulation 9,10