The perioperative management of treatment with anticoagulants and platelet aggregation inhibitors

Abstract

Background: When giving anticoagulants and inhibitors of platelet aggregation either prophylactically or therapeutically, physicians face the challenge of protecting patients from thromboembolic events without inducing harmful bleeding. Especially in the perioperative period, the use of these drugs requires a carefully balanced evaluation of their risks and benefits. Moreover, the choice of drug is difficult, because many different substances have been approved for clinical use.

Method: We selectively searched for relevant publications that appeared from 2003 to February 2013, with particular consideration of the guidelines of the European Society of Cardiology, the Association of Scientific Medical Societies in Germany (AWMF), the American College of Cardiology, and the American Heart Association.

Results: Vitamin K antagonists (VKA), low molecular weight heparins, and fondaparinux are the established anticoagulants. The past few years have seen the introduction of orally administered selective inhibitors of the clotting factors IIa (dabigatran) and Xa (rivaroxaban, apixaban). The timing of perioperative interruption of anticoagulation is based on pharmacokinetic considerations rather than on evidence from clinical trials. Recent studies have shown that substituting short-acting anticoagulants for VKA before a procedure increases the risk of bleeding without lowering the risk of periprocedural thromboembolic events. The therapeutic spectrum of acetylsalicylic acid and clopidogrel has been broadened by the newer platelet aggregation inhibitors prasugrel and ticagrelor. Patients with drug eluting stents should be treated with dual platelet inhibition for 12 months because of the risk of in-stent thrombosis.

Conclusion: Anticoagulants and platelet aggregation inhibitors are commonly used drugs, but the evidence for their perioperative management is limited. The risks of thrombosis and of hemorrhage must be balanced against each other in the individual case. Anticoagulation need not be stopped for minor procedures.

Figure 1

Using the CHA2DS2-Vasc score to estimate the risk of thromboembolism in patiens with atrial fibrillation. A score of 1 or higher implies that oral anticoagulation with a vitamin K antagonist or a new oral anticoagulant is indicated for life, regardless of the clinical pattern of atrial fibrillation (paroxysmal, persistent, or permanent). Women under age 65 with no further risk factors (other than being female) are an exception: if their formal CHA2DS2-Vasc score is 1, anticoagulation is not indicated, and acetylsalicylic acid is not indicated either (3)

Figure 2

The perioperative management of platelet inhibition depends on the magnitude of the risks of thrombosis and hemorrhage. These risks are in inverse relation. The triangles indicate the extent of the risk. The blue arrows represent continued administration of platelet aggregation inhibitors, while the red circles with a diagonal line through them represent interruption of their administration. The greater the risk of thromboembolism, the more necessary it is to continue giving the drugs. Dual inhibition of platelet aggregation can be interrupted for procedures with a high risk of bleeding and a low risk of thrombosis (modified from e12)

Figure 3

Flowchart for the preoperative management of patients receiving platelet aggregation inhibitors: a) Management of patients with an indication for surgery under dual inhibition of platelet aggregation; b) Recommendations for the management of elective procedures for patients with coronary stents, depending on the type of stent and time of implantation (modified from 39, 40). ASA, actetylsalicylic acid; BMS, bare metal stent; DES, drug eluting stent