Peri-Operative anticoagulation /antiplatelet therapy A Shift in Paradigm BMHGT04/29/09

Peri-Operative Peri-Operative anticoagulation /antiplatelet anticoagulation /antiplatelet

therapytherapyA Shift in Paradigm A Shift in Paradigm

BMHGT BMHGT

04/29/0904/29/09

Balancing Thromboembolic and Bleeding Risks in the Perioperative

Period

Thromboembolic risks:

(1)Disease specific thromboembolic risks when discontinuing warfarin or ASA )stents

(2)Hypercoagulability associated with surgery. Bleeding risks:

(1) the patient

(2) the use of anticoagulant/antiplatelet therapy

(3) the surgery or procedure

Thromboembolic risk when discontinuing OAC

Bleeding Risks

Patient: Previous history of bleeding, especially with invasive

procedures or trauma Use of concomitant antiplatelet and nonsteroidal

antiinflammatory medications.Procedure: High :include major operations and procedures (lasting

>45 minutes) Low : include non-major operations and procedures

(lasting <45 minutes)Perioperative anticoagulants: 2-day period : 2 to 4% for major surgery 0 to 2% for non-major surgery.

Warfarin

INR starts to fall at approximately 29 hours after the last dose of warfarin

A half-life of approximately 22 hours It is reasonable to start bridging therapy

approximately 60 hours after the last dose of

warfarin.

Perioperative bridging algorithm

Low risk of ATE or VTE:

No heparin bridging preoperatively and only prophylactic doses of LMWH or UFH postoperatively in conjunction with resumption of warfarin.

Low-molecular-weight-heparin (LMWH)

Allowed bridging therapy to be administered to outpatients.

Doses of LMWH that are recommended for treatment of venous thromboembolism are administered once or twice daily, generally for 3 days before surgery.

Required to determine whether the benefit of

bridging therapy outweighs the associated risks of bleeding.

Unfractionated heparin (UFH)

Advantage: A short half-life(60 minutes) easily reversed (by protamine sulfate)

Disadvantage:Disadvantage: Intravenous administration necessitates

hospitalization before surgery, Inconvenient and expensive.

Perioperative bridging protocol

Instructions regarding IV UFH use 1. Should start at least 2 days prior to surgery at therapeutic

dose using a validated, aPTT-adjusted, weight-based

nomogram (ie, 80 U/kg bolus dose IV followed by a

maintenance dose of 18 U/kg/h IV) 2. Discontinue 6 hours prior to surgery 3. Restart no less than 12 hours postoperatively at the

previous

maintenance dose once hemostasis is achieved 4. Discontinue IV UFH when INR is in therapeutic range (1.9)

Perioperative bridging protocol

Instructions regarding LMWH use: 1. Should start at least 2 days prior to surgery at BID therapeutic dose (ie, enoxaparin 1 mg/kg SC BID or dalteparin 100 IU/kg SQ BID) 2. Discontinue at least 12 hours prior to surgery (if

surgery is in early A.M. consider holding previous evening dose) 3. Restart usual therapeutic dose within 12–24 hours

after surgery once hemostasis is achieved 4. Discontinue LMWH when INR in therapeutic range

(1.9)

Perioperative bridging protocol

Instructions regarding warfarin use: 1. Stop warfarin at least 4 days prior to surgery 2. Check INR 1 day prior to surgery If 1.5, proceed with surgery If 1.5 to 1.8, consider low-level reversal with Vitamin K If 1.8, recommend reversal with Vitamin K (either 1 mg

SC or 2.5 mg PO) 3. Recheck INR day of surgery 4. Restart maintenance dose of warfarin the evening of

surgery 5. Daily INR until in therapeutic range (1.9)

Recommendations Recommendations

The Seventh American College of Chest Physician Consensus Conference:

Intermediate risk of thromboembolism －prophylactic (or higher) dose UFH or LMWH as perioperative bridging therapy

High risk of thromboembolism－ full-dose UFH or LMWH Low risk of bleeding－ Continue warfarin therapy at a lower dose to

maintain an INR of 1.3 to 1.5.

Orthopedic surgery in patients with Orthopedic surgery in patients with coronary stents coronary stents

Bare metal stentsBare metal stents Drug eluted stents (sirolimus/pacltaxel)Drug eluted stents (sirolimus/pacltaxel) Dual antiplatelet therapy recommended for Dual antiplatelet therapy recommended for

12 months 12 months Life long ASA in low bleeding risk ptsLife long ASA in low bleeding risk pts 45% mortality on stopping ASA (without 45% mortality on stopping ASA (without

surgery)_-surgery)_- Heparin does not prevent stent thrombosis Heparin does not prevent stent thrombosis

Current recommendations Current recommendations

Assess stent thrombosis risk Assess stent thrombosis risk Defer surgery (bare metal one month; 12 Defer surgery (bare metal one month; 12

month for drug eluted )month for drug eluted ) Do not stop ASA; use coumadin with ASA Do not stop ASA; use coumadin with ASA

for VTE prophylaxis (never ASA alone)for VTE prophylaxis (never ASA alone) Assess resources to revitalize thrombosed Assess resources to revitalize thrombosed

stent in hospital ( very high mortality)stent in hospital ( very high mortality)