Algorithm of Dunn for the Perioperative Management of a Patient Receiving Oral Anticoagulation

Patient selection: on an oral anticoagulant

Parameters:

(1) annual risk of stroke without anticoagulation

(2) risk of bleeding associated with the procedure

(3) patient's strong preference for bridging

where:

• A low risk for stroke corresponds to atrial fibrillation with <= 2 risk factors for stroke.

• A moderate risk for stroke corresponds to a bileaflet mechanical atrial valve replacement.

• A high risk for stroke corresponds to a mechanical mitral valve replacement.

A person who is undergoing a minor procedure may not need to stop the oral anticoagulants. If there is some risk of bleeding associated with the procedure, then anticoagulants may be stopped a few days prior to surgery (many patients are subtherapeutic after 2 days without therapy).

Preoperative bridging:

(1) Stop oral anticoagulants 4 days prior to surgery.

(2) Start heparin (usually low molecular weight heparin at a therapeutic dose) 2 days prior to surgery.

(3) If the patient cannot take heparin then another parenteral anticoagulant is used.

Patients should be restarted on oral anticoagulants in the evening after the procedure provided hemostasis is adequate.

Postoperative bridging:

(1) Start heparin (usually low molecular weight heparin at a therapeutic dose) 12-24 hours after surgery if there is no excessive bleeding.

(2) Postoperative bridging may significantly increase the risk of major bleeding.