Article

Perioperative management of warfarin and antiplatelet therapy

Author and Disclosure Information

ABSTRACT

Perioperative management of patients on warfarin or antiplatelet therapy involves assessing and balancing individual risks for thromboembolism and bleeding. Discontinuing anticoagulant and antiplatelet therapy is usually necessary for major surgery but increases the risk of thrombotic events. Bridge therapy, the temporary perioperative substitution of low-molecular-weight heparin or unfractionated heparin in place of warfarin, is an effective means of reducing the risk of thromboembolism but may increase the risk of bleeding. The timing of warfarin withdrawal and timing of the preoperative and postoperative components of bridge therapy are critical to balancing these risks. Perioperative management of antiplatelet therapy requires special care in patients with coronary stents; the timing of surgery relative to stent placement dictates management in these patients.

KEY POINTS

  • Determining when and how to use bridge anticoagulation therapy depends on the patient’s risk for thromboembolism, which is in turn based on the indication for warfarin—ie, a mechanical heart valve, atrial fibrillation, or prior venous thromboembolism.
  • Factor patient preference into whether and how to use bridge therapy: many patients are more concerned about stroke risk than bleeding risk, regardless of the relative frequency of these events.
  • Anticoagulation with warfarin often does not need to be interrupted for patients undergoing minor surgery, such as some ophthalmic, dental, dermatologic, and gastrointestinal procedures.
  • Premature discontinuation of antiplatelet therapy in surgical patients with recent coronary stent placement significantly raises the risk of catastrophic perioperative stent thrombosis.


 

References

Perioperative management of surgical patients who require temporary discontinuation of vitamin K antagonists (warfarin) or antiplatelet drugs is complicated. The risk of a thrombotic event during interruption of anticoagulant or antiplatelet therapy must be weighed against the risk of bleeding when such therapy is used in close proximity to a surgical procedure. This balancing of risks is guided by the patient’s individual risk for thromboembolism or bleeding and underlying conditions such as the presence of a mechanical heart valve or a coronary stent.

High-profile adverse events have made anticoagulant and antiplatelet management one of the most highly litigated aspects of perioperative medicine. Moreover, there is a paucity of randomized clinical trial data and definitive guidelines to address the perioperative needs of patients on antithrombotic therapy. Treatment protocols vary depending on many underlying factors, such as the presence of mechanical heart valves, comorbidities, stent type and location, patient age and medical history, and type of surgical procedure. While recent attention has focused on genetic variations that result in higher or lower sensitivity to warfarin in some patients, routine genetic testing for warfarin sensitivity is controversial and not part of widespread practice at this time.

The first portion of this article explores key issues and principles in the perioperative management of surgical patients on warfarin therapy, and the second portion does the same for surgical patients on antiplatelet therapy.

ACCP RECOMMENDATIONS FOR PERIOPERATIVE ANTICOAGULANT MANAGEMENT

In 2008 the American College of Chest Physicians (ACCP) published the latest update of its consensus guidelines for the perioperative management of patients receiving antithrombotic therapy. 1 The guidelines’ recommendations for anticoagulant management are based on stratification of patients into risk categories ( Table 1 ) according to their underlying indication for long-term anticoagulation—ie, presence of a mechanical heart valve, history of atrial fibrillation, or history of venous thromboembolism (VTE).

Patients with mechanical valves who are at high risk for perioperative thromboembolism include those with any mechanical mitral valve, an older valve, or a history of stroke or transient ischemic attack (TIA). Patients with atrial fibrillation who are at high risk include those with a recent stroke or TIA, rheumatic valvular heart disease, or a CHADS 2 score of 5 or 6. (The CHADS 2 scoring system assigns one point each for a history of congestive heart failure, hypertension, age greater than 75 years, or diabetes, and two points for history of stroke or TIA.) Patients with a history of VTE within the prior 3 months are also considered high risk.

Bridging anticoagulation (bridge therapy)—ie, the temporary use of intravenous unfractionated heparin (IV UFH) or low-molecular-weight heparin (LMWH) prior to surgery—is central to the ACCP’s recommendations for perioperative management in patients on long-term anticoagulant therapy. Key ACCP recommendations 1 for these patients, according to their risk for thromboembolism ( Table 1 ), are as follows:

  • High risk —bridging anticoagulation with therapeutic-dose subcutaneous LMWH or IV UFH
  • Moderate risk —bridging anticoagulation with therapeutic-dose subcutaneous LMWH, therapeutic-dose IV UFH, or low-dose subcutaneous LMWH
  • Low risk —bridging anticoagulation with low-dose subcutaneous LMWH or no bridging.

Pages

Next Article: