Post on 06-Jan-2016
description
Peri-operative management of anticoagulation
Marc Carrier MD, MSc FRCPCAssistant Professor, University of OttawaAssociate Scientist, Ottawa Health Research Institute
Today
• Peri-operative bridging– Warfarin– ASA– Clopidogrel
• Post-operative Thromboprophylaxis– Orthopedic surgery– General surgery
Peri-op bridging(warfarin)
Dilemma:Pre and Post-op Risk assessment
Preventable thromboembolism
Major bleeds
Pharmacokinetics
• INR will normalise in a time period ranging from 50 to over 200 hours but 23% remain higher than 1.2 five days after d/c OACs
INR after warfarin induction
• When reinitiated a therapeutic level of anticoagulation will be achieved in a variable time period ranging from 2 to 10 days
• When OACs are discontinued and re-initiated the length of time with sub-therapeutic INRs is highly variable
• As a consequence clinicians need to consider “bridging therapy”
Assessment of Thrombosis Risk
• Venous Vs Arterial Thrombosis
Arterial Thrombosis – High riskCHADS2
Congestive Heart Failure
1
Hypertension 1
Age >70 1
Diabetes 1
Stroke/TIA 2
Total
0-2: 1.5-2.5%/yr stroke
> 2: 4.0-18.2%/yr stroke
Risk of Bleeding from Procedure
• Low Risk Procedure– Dental procedure
– Skin Biopsy
– Cataract surgery
– GI:
• Diagnostic colonoscopy or endoscopy
• EGD +/- biopsy• Flexible Sphincteromy+/- biopsy• Biliary/pancreatic stent
• ERCP without sphincterotomy
• Moderate or High risk
Bleeding risk→
Thrombosis Risk↓
Low High
Low
High Bridge
STOP
STOP
STOP
Bridging with LMWH
D -5 OR D5-10
Clinic
Home
Local lab
X
Summary(pre-op)
• Stop warfarin 5 days before surgery• Assess need for peri-operative bridging
• High risk: Therapeutic LMWH > IV UFH• Moderate risk: Therapeutic > prophylactic LMWH > IV UFH• Low risk: no bridging or prophylactic LMWH• If therapeutic LMWH is used:
– 50% therapeutic dose on OR day -1– No need to follow anti-Xa levels
• If prophylactic LMWH is used:– Last dose 24 hours before OR
• If IV UFH is used: Stop infusion 4 hours pre-op
• STAT INR 1-2 days before OR day• If INR > 1.5 give 1-2 mg of PO vitamin K
Summary(post-op)
• Resume VKA 12 to 24 hours post op• Good hemostasis
• PO intake
• Epidural is out
• Resuming Post-op LMWH bridging is • POD1 if good hemostasis
• If using therapeutic doses of LMWH/UFH» POD1 if minor surgical procedure» Consider resuming on POD2 if high bleeding risk major surgery» No need to follow anti-Xa
• D/C LMWH or UFH once INR therapeutic – i.e. > 2.0 or 2.5 depending on indication
Peri-op bridging(ASA, clopidogrel)
ASA/Clopidogrel
• If not high risk for cardiac events:– Stop 7 to 10 days before the procedure– Resume on POD1 (24 hours post-op)
• Adequate hemostasis
• If high risk of cardiac events (exclusive of coronary stents) for non-cardiac surgery
• Continue aspirin• Hold clopidogrel at least 5 days and preferable within 10 days of
surgery
• If high risk of cardiac events (exclusive of coronary stents) for CABG• Same as above• If ASA is interrupted then needs to be reinitiated between 6 and 48
hours after CABG
ASA/Clopidogrel
• Coronary stent• If bare metal coronary stent within 6 weeks
– Continue ASA and clopidogrel peri-operatively
• If drug-eluting stent within 12 months– Continue ASA and clopidogrel peri-operatively
• In patients with coronary stents who have interruption of ASA or clopidogrel
– No need to routinely bridge these patients
Prevention of Venous Thromboembolism
General Principles
• Should think about thromboprophylaxis for every patients• Mechanical methods alone in patients at high risk of
bleeding only!• May be used as an adjunct to anticoagulant
• The use of ASA alone as thromboprophylaxis is not recommended for any patient group!
What is the risk?
Risk factors for VTE
General Surgery
• Low-risk general surgery patients undergoing minor procedure• No need for thromboprophylaxis
• Early and frequent ambulation
• Moderate-risk general surgery patients who are undergoing a major procedure for benign disease
• LMWH, IFH sc TID or BID, or fondaparinux
• Higher-risk general surgery patients who are undergoing a major procedure for cancer
• LMWH, UFH sc TID or fondaparinux
• Continue thromboprophylaxis until discharge except:• Cancer patients: at least 7 to 10 days
• Cancer patients + other risk factors: up to 28 days
General Surgery
• Entirely laparoscopic surgery procedure with no additional thromboembolic risk factors
• No need for thromboprophylaxis• Early and frequent ambulation
• If additional VTE risk factors then thromboprophylaxis until D/C home (unless cancer)
Orthopedic Surgery
• LMWH– Prophylactic doses– Dalterapin 5000 IU OD, enoxaparin 40 mg OD or 30 mg bid,
tinzaparin 4500 IU OD– Starting on POD1
• Fondaparinux (2.5 mg started 6 to 24 hours post-op)• Warfarin
– target INR 2.0-3.0
• Rivaroxaban– 10 mg OD
• Dabigatran– 220 or 150 mg OD
• Not ASA, mechanical methods alone, dextran, or UFH
Duration
• THR, TKR or HFS:• At least 10 days
• THR, HFS:• Thromboprophylaxis should be extended beyond 10 days and
up to 35 days
• TKR: • Can consider extending thromboprophylaxis beyond 10 days
and up to 35 days
• Knee arthroscopy:• No need for thromboprophylaxis if no other VTE risk factors• If other risk factors, consider LMWH
Trauma
• Thromboprophylaxis if possible• LMWH alone• LMWH + mechanical methods• Hold LMWH if high risk of bleeding
– Don’t forget to resume…
• No screening U/S for DVT• No IVC filter insertion as thromboprophylaxis• Continue thromboprophylaxis until hospital D/C• If patient undergoes inpatients rehab:
• Switch to warfarin (target 2.0-3.0) until D/C home• Or continue LMWH prophylaxis
Thank You