• long-term anticoagulation therapy often needs to be interrupted for various reasons (most commonly due to planned diagnostic or surgical procedures); interruption in emergencies is discussed elsewhere (→ Neutralizing the anticoagulant effect)
  • the decision to discontinue anticoagulation periprocedurally represents a complex balancing act between the estimated risk of thromboembolism and bleeding
  • these questions need to be addressed:
    • is it necessary to discontinue anticoagulation?
    • if so, how long before the procedure should it be discontinued?
    • is bridging therapy necessary? at what dose?
    • when should anticoagulant therapy be restarted after the procedure?
  • to answer these questions, the following factors must be evaluated:
    • individual risk of thromboembolism
    • risk of bleeding (considering the characteristics of the patient and the planned procedure)
      • type of procedure and its risk of bleeding
      • features of the prescribed anticoagulant agent (warfarin x DOAC)
      • renal functions
  • warfarin requires a rather complex procedure – timely discontinuation (at least 3-5 days before the procedure), followed by monitoring of INR decline and starting LMWH once INR gets below 2 (if bridging is indicated)
  • DOACs simplify the situation because of their rapid onset of action and predictable, relatively short-lasting normalization of coagulation parameters (thus, LMWH bridging is not necessary in most cases)

Is it really necessary to stop anticoagulant therapy?

  • it is always a matter of better or worse estimation because the balance between the risk of thromboembolism when anticoagulation is withdrawn, and the risk of bleeding when it is continued is often unclear
    • TE is relatively rare but can be fatal
    • bleeding with continued anticoagulation is more common but typically less clinically relevant, usually without permanent sequelae

Thromboembolism risk assessment

  • use the CHA2DS2-VASc score in patients with Afib
  • in patients with venous thrombosis (VTE), consider the time elapsed since the VTE diagnosis and the presence/absence of thrombophilia (a prothrombotic state)
  • in patients with a mechanical valve, the risk depends on the type and location of the valve and the presence of contributing risk factors (AFib, heart failure, hypertension, diabetes, age >75 years, previous stroke)
Clinical Indication for Anticoagulant Therapy
Thromboembolic Risk Category Atrial Fibrillation Mechanical Heart Valve VTE
High risk
(annual risk >10%)
  • CHADS2 score 5-6
  • recent (< 3 months) stroke/TIA
  • rheumatic valvular heart disease
  • any mechanical mitral valve
  • older aortic mechanical valve (caged ball, tilting disk)
  • recent (< 3 months) stroke or TIA
  • recent (< 3 months) VTE
  • high-risk thrombophilia (deficiency of protein C, protein S, or antithrombin; antiphospholipid syndrome; homozygous factor V Leiden or
    prothrombin gene mutation)
Moderate risk
(annual risk 5% to 10%)
CHADS2 score 3-4 bileaflet aortic valve prosthesis with ≥1 risk factor
  • VTE within 3–12 months
  • moderate-risk thrombophilia (heterozygous factor V Leiden
    or prothrombin gene mutation)
  • recurrent VTE
  • active cancer (metastatic or treated within the past 6 months)
Low risk (annual risk <5%) CHADS2 score 0–2 (no prior stroke or TIA) bileaflet aortic valve prosthesis without any risk factors VTE >12 months ago

Bleeding risk assessment

  • consider a combination of individual patient´s risks and the risk associated  with the procedure itself
  • take into account the location and invasiveness of the procedure
  • many procedures can be safely performed without interrupting anticoagulation (either warfarin or DOACs), such as dermatological, ophthalmological, and dental procedures
CHA2DS2-VASc score
ABC score
  • in addition to clinical factors, the ABC-bleeding risk score also incorporates the biomarkers: high-sensitivity troponin T, growth differentiation factor–15, and hemoglobin

ABC-stroke score

ABC-stroke score

ABC-bleeding score

ABC-bleeding score
HAS-BLED score
  • a tool to guide the decision to initiate anticoagulation in patients with Afib
  • always compare the risk for major bleeding (calculated by the HAS-BLED score) with the risk of thromboembolic events (calculated by the CHA2DS2-VASc score) ⇒  does the benefit of anticoagulation outweigh the risk of bleeding?
  • a study comparing HEMORR2HAGES, ATRIA, and HAS-BLED showed superior performance of the HAS-BLED score compared to the other two scores
HAS-BLED score
uncontrolled BP (SBP >160 mmHg)
Abnormal liver/renal function
renal disease – dialysis, transplant, Cr >2.26 mg/dL or >200 µmol/L
liver disease – cirrhosis or bilirubin >2x normal or AST/ALT/AP >3x normal
Stroke previous stroke
prior major bleeding or predisposition to bleeding
Labile INR unstable INR, time in therapeutic range <60% 1
Elderly age ≥ 65 years
medication predisposing to bleeding –  aspirin, clopidogrel, NSAIDs
heavy alcohol use
HAS-BLED score
Pisters et al. annual ICH risk
Lip et al. annual ICH risk
0 1.1% 0.9%
1 1% 3.4%
2 1.9% 4.1%
3 3.7% 5.8%
4 8.7% 8.9%
5 12.5% 9.1 %
Not enough data for higher scores; risk is most likely > 10%

A score ≥ 3 is associated with an increased risk of major bleeding.
Frequent monitoring, DOAC use, or alternatives to anticoagulation (such as
LAA occlusion) are recommended.

ORBIT score
  • The ORBIT bleeding risk score has a superior predictive ability for major bleeding in AFib patients compared to the HAS-BLED and ATRIA risk scores. The ORBIT risk score may provide a simple, easy-to-remember tool to assist in clinical decision-making [O´Brian,  2015]  [Hilkens, 2017]
Older age ( >75 y) 1
Reduced hemoglobin/Hct/anemia  (men <13 g/dL and Hct < 40%, women < 12 g/dL and Hct < 36% ) 2
Bleeding 2
Insufficient kidney function (GFR < 60 mL/min/1.73 m2) 1
Treatment with antiplatelets 1
Maximum score 7
score 0–2 – low risk ~ 2.4% / y
score 3 –  medium risk ~ 4.7% / y
score ≥ 4 – high risk ~ 8.1% / y
The risk of bleeding is unlikely to be increased
simple dental procedures
The risk of bleeding is probably not increased
cataract surgery
dermatological procedures
TRUS (ultrasound-guided prostate biopsy)
spinal and epidural punctures
carpal tunnel surgery
The risk of bleeding is apparently not increased
transbronchial biopsy
colonoscopic polypectomy
endoscopic gastric biopsy
ultrasound-guided biopsies
The risk of bleeding is possibly increased
The risk of bleeding is probably increased total endoprosthesis (TEP)

Timing of anticoagulant therapy discontinuation

  • discontinue warfarin 3-5 days before the procedure
  • monitor INR decline
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Discontinuation of DOAC before neuraxial anesthesia

  • a higher perioperative hemorrhagic risk is assumed; therefore, a longer interval is recommended
    • dabigatran:  discontinue 4-5 days before surgery
    • Xa inhibitors: discontinue  3-5 days before surgery
  • restart DOAC ≥ 24 hours after the procedure
  • consider LMWH bridging in high-risk patients
  • separate guidelines for spinal and analgesic procedures are here and here

Is bridging required?

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Restart of the anticoagulant therapy

  • the timing of anticoagulation restart is sometimes a neglected issue, although it is a crucial factor influencing the outcome
  • generally, it is not necessary to start full anticoagulation (heparin, LMWH, DOAC) within 6-12 hours after the procedure
  • according to the BRIDGE trial, initiating full anticoagulant therapy within 24-72 hours after the procedure is not recommended
    • in patients at high risk of bleeding, wait for 72 h (especially for DOACs or LMWH, where the onset of anticoagulant effect is rapid)
    • warfarin may be given earlier due to its delayed onset of full action

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Perioperative and Periprocedural Management of Anticoagulant Therapy
link: https://www.stroke-manual.com/perioperative-and-periprocedural-management-of-anticoagulant-therapy/