What cardiac and diabetes medications, such as warfarin (anticoagulant), aspirin (antiplatelet agent), metformin (oral hypoglycemic agent), and beta-blockers (beta-adrenergic blocking agents), should be stopped prior to surgery and how long before, considering conditions like impaired renal function and risk of bleeding or thromboembolic events?

Perioperative Management of Cardiac and Diabetes Medications

For elective surgery, anticoagulants, antiplatelets, and certain diabetes medications should be temporarily discontinued based on bleeding risk, thrombotic risk, and medication pharmacokinetics to minimize perioperative complications.

Anticoagulants

Warfarin

• Stop 4-5 days before surgery to allow INR to normalize (target INR ≤1.5) 1, 2
• For patients with mechanical heart valves or venous thromboembolism within 3 months, bridging with low molecular weight heparin (LMWH) is recommended 2
• For patients with atrial fibrillation without additional risk factors, routine bridging is not recommended 2
• Resume warfarin 12-24 hours after surgery when adequate hemostasis is achieved 1, 2

Direct Oral Anticoagulants (DOACs)

• Dabigatran:

  • For low-to-moderate bleeding risk procedures: Stop 1 day before if CrCl ≥50 mL/min; 2 days before if CrCl <50 mL/min 2
  • For high bleeding risk procedures: Stop 2 days before if CrCl ≥50 mL/min; 4 days before if CrCl <50 mL/min 2

• Rivaroxaban and Apixaban:

  • For low-to-moderate bleeding risk procedures: Stop 1 day before surgery 2
  • For high bleeding risk procedures: Stop 2-3 days before surgery 2
  • For patients with renal dysfunction undergoing major surgery: Stop 3 days before surgery 2

• DOAC resumption: Resume at least 24 hours after low-to-moderate bleeding risk procedures and 48-72 hours after high bleeding risk procedures 2

• Bridging anticoagulation is not required with DOACs except in patients with recent (<3 months) venous thromboembolism 2

Mechanism

Anticoagulants prevent clot formation by inhibiting the coagulation cascade. Their discontinuation is necessary to prevent excessive surgical bleeding, but must be balanced against thrombotic risk 2, 3.

Antiplatelet Agents

Aspirin

• For most procedures, continue until the day before surgery 2
• For high bleeding risk procedures (intracranial, spinal surgery), stop 5 days before 2, 4
• For patients with coronary stents, management should be coordinated with cardiology 2

Clopidogrel and Other Thienopyridines

• Stop 7 days before surgery unless point-of-care testing is used to check platelet function 2, 5
• For urgent surgery, discontinue 5 days prior to procedures with major bleeding risk 5, 4
• For patients with recent coronary stent placement, elective surgery should be postponed (4-6 weeks for bare metal stents, 6 months for drug-eluting stents) 2

Mechanism

Antiplatelet drugs cause irreversible inhibition of platelets. Normal platelet function is restored at a rate of 10-15% per day as new platelets are produced, requiring longer discontinuation periods 2, 4.

Diabetes Medications

Metformin

• Stop 24-48 hours before procedures involving contrast media or with risk of acute kidney injury 6
• This prevents lactic acidosis if renal function deteriorates perioperatively 6

Insulin

• Long-acting insulin: Reduce dose by 25-50% the evening before and morning of surgery 6
• Short-acting insulin: Hold on the morning of surgery 6
• Monitor blood glucose levels closely perioperatively 6

Oral Hypoglycemic Agents

• Sulfonylureas: Hold on the day of surgery to prevent hypoglycemia 6
• SGLT-2 inhibitors: Stop 3-4 days before surgery to prevent euglycemic diabetic ketoacidosis 6

Surgery-Specific Considerations

High Bleeding Risk Procedures

• Neurosurgery, spinal surgery, cardiac surgery, major vascular procedures 2, 4
• Require more conservative management with longer discontinuation periods for anticoagulants and antiplatelets 2

Low Bleeding Risk Procedures

• Dental procedures, cataract extraction, minor dermatologic procedures 2, 3
• Can often be performed without interrupting anticoagulation, especially warfarin 2, 3

Common Pitfalls and Caveats

• Inadequate discontinuation time: Even when warfarin is stopped 7 days before surgery and INR is normalized, patients may still have increased intraoperative blood loss 7
• Failure to consider renal function: Medication clearance, especially for DOACs and metformin, is significantly affected by renal impairment 2
• Overlooking thrombotic risk: Abrupt discontinuation without appropriate bridging in high-risk patients can lead to thromboembolic events 2, 8
• Premature resumption: Restarting anticoagulants too soon after surgery increases bleeding risk, especially with DOACs due to their rapid onset of action 2
• Inadequate communication: Management of patients with coronary stents requires coordination between surgery, anesthesia, and cardiology teams 2