Perioperative+Anticoagulation+Guidelines

= // I. INTRODUCTION // = Patients on chronic anticoagulation frequently require interruption of their therapy for surgery, exposing them to thromboembolic risk for that period of time. Controlled trials to answer conclusively how best to do this are not available, but general guidelines (below) based on best available data are useful. Considerations include the indication for anticoagulation, the timing of the most recent thromboembolic event and the nature of the surgery.

References [|ACCP guidelines] [|Up to Date]

**// II. RECOMMENDATIONS FOR MOST IN-PATIENT OR OUT-PATIENT SURGICAL PROCEDURES TAKING ORAL ANTICOAGULANTS: //** The decision regarding interruption of anticoagulation before, during or after a surgical procedure depends on the indication for chronic Coumadin. Patients with chronic atrial fibrillation have an extremely low risk of an adverse event off Coumadin for 7-10 days (4 in 10,000) compared to patients with an acute venous thromboembolism in the last month (7,162 in 10,000). These guidelines reflect the risk of stopping anticoagulation versus the increased risk of giving preoperative Heparin and causing hemorrhage.

To bridge coumadin, stop the coumadin 5 days prior to surgery and start enoxaparin (1mg/kg q12 hrs). Patient should hold the enoxaparin dose the night before surgery.


 * __Indications for Preoperative Bridging Therapy in Common Clinical Circumstances__

Chronic Atrial Fibrillation** [|Calculate Chads 2 score] Chads 2 score 1-2 No bridging Chads 2 score 3-4 Full dose or low dose bridging enoxoparin Chads 2 score 5-6 Full dose bridging enoxaparin (1 mg/kg q12 hrs)

Avoid surgery if possible if mechanical heart valve is freshly placed Bileaflet AVR without stroke risk factor: No bridging Bileaflet AVR with 1 stroke risk factor: Full dose or low dose bridging enoxaparin Any MVR, or older AVR (ball cage, tilted disc) or recent CVA: Full dose or bridging enoxaparin
 * Mechanical Heart Valve**

Consider delaying surgery if possible. A vena caval filter should be considered if acute venous thromboembolism has occurred within two weeks or if the risk of bleeding during or after surgery is high. IV Heparin or low molecular weight Heparin (LMWH), enoxaparin (1 mg/kg q 12 h) should be used before surgery. IV Heparin should be discontinued 6-12 hours preop with a PTT which has normalized. Enoxaparin should be discontinued 18-24 hours preoperatively.
 * Acute Venous Thromboembolism**

If a patient's INR is between 2.0 and 3.0, four scheduled doses of warfarin should be withheld to allow the INR to fall spontaneously to 1.5 or less before surgery. Warfarin should be withheld for a longer period if the INR is normally maintained above 3.0 or if it is necessary to have it at a lower level for surgery (i.e. <1.3). The INR should be measured a day before surgery to ensure adequate progress in the reversal of anticoagulation; the physician then has the option of administering a small dose (1 mg, subcutaneously) of Vitamin K, if required (that is, if the INR is 1.8 or higher, or postponing surgery). If the patient is hospitalized for other reasons, prophylactic subcutaneous Heparin (5,000 Unit q8h or Q12h) may be administered, but hospitalization is not recommended solely for this purpose.
 * Recurrent Venous Thrombolism (or after acute VTE after one month)**


 * Acute Arterial Thrombosis or Embolization**
 * C)** Elective surgery should be avoided in the first month, but if surgery is essential, preoperative IV Heparin or low molecular weight Heparin (LMWH), enoxaparin (1 mg/kg q 12h) should be administered. IV Heparin should be discontinued 6-12 hours pre-op with a PTT which has normalized. Enoxaparin should be discontinued 18-24 hours preoperatively.

Most patients can be simply restarted on their outpatient Coumadin dose. This should be done as an inpatient and the patient re-referred to Coumadin clinic. In high risk patients, while the Coumadin is rising to thereputic levels, the patient should be restarted on enoxaparin, as soon after the surgery as the patient will tolerate the bleeding risk.
 * __RESTARTING COAGULATION AFTER SURGERY__**

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