With a few exceptions, chronic medical therapy should not be adjusted prior to presentation for surgery. It is prudent to maintain adequate treatment of medical conditions, including administration of oral medications with small sips of water on the day of surgery. Surgery presents problems such as bleeding, fasting, and physiologic stresses that require anticipation prior to surgery. Additionally, preoperative examination and testing may dictate the need for the initiation or adjustment of medications.
Chronic medical therapy must be reviewed in a timely fashion before surgery. This review can take place in a variety of settings, including the surgeon’s office, a primary medical provider or specialist’s office, or in a preanesthesia testing unit. A phone discussion may be appropriate in many circumstances. Particular attention should be focused on anticoagulation treatment, including herbal remedies, diabetes mellitus therapy, and antihypertensive treatment.
The surgical patient on anticoagulation therapy needs special attention, especially with the proliferation of novel anticoagulants and new management guidelines. Surgical bleeding risk must be weighed against thrombosis risk. Abruptly stopping anticoagulants may induce a hypercoagulable state. This adds to the prothrombotic nature of the surgical period itself.
Example 1—A patient on aspirin therapy for primary prevention of stroke or cardiovascular disease scheduled for a procedure with a high risk of bleeding. Aspirin therapy should be withheld for seven days, or less for lower-dose aspirin regimens.
Example 2—A patient on dual antiplatelet therapy for recent coronary intervention with unclear surgical bleeding risk. The clinical decision making is less clear; institutional guidelines should inform decisions.
Warfarin therapy is stopped 5 days prior to surgery unless the risk of surgical bleeding is very low. If the starting INR is greater than 2.5, then more than 5 days may be necessary to normalize the INR ratio, and laboratory findings should guide surgical preparedness. For emergency surgery, vitamin K, fresh frozen plasma, or a combination of the two may expedite anticoagulation reversal. Bridging therapy with heparin, fractionated or unfractionated, should be considered. Temporal relation of the initial thrombotic event can dictate the need for bridging therapy; a recent thrombotic event suggests the need for bridging therapy. For atrial fibrillation and mechanical heart valves, recent trends in perioperative care favor bridging therapy for high-risk patients only.
Newer, oral, direct thrombin inhibitors, such as dabigatran do not require bridging therapy because of rapid onset and offset. Patients with normal renal function can stop dabigatran 2 days prior to surgery. If creatinine clearance is decreased, longer stoppage time may be necessary. Thrombin clotting time can be used to assess residual anticoagulant effects. These agents can be started 24–72 hours after surgery depending on bleeding risk.
Patients on aspirin therapy for secondary stroke prevention or cardiovascular events should continue the therapy intraoperatively. However, bleeding risk may be unacceptably high during certain procedures such as spine surgery, plastic surgery, neurosurgery, ...