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Guidelines on antithrombotic therapy in patients with mechanical heart valve replacements (MHVR) by the American College of Cardiology/American Heart Association (ACC/AHA)1 2 and by the European Society of Cardiology (ESC)3 agree on most issues. Both accept the need for anticoagulation intensity stratification according to valve position and other risk factors, and that many patients can be managed with lower-intensity anticoagulation than previously recommended. Both concede that individual patient risk assessment is crucial, but, the ACC/AHA uses this only to adjust anticoagulation and/or antiplatelet therapy, whereas the ESC underlines the importance of risk reduction as an integral part of overall antithrombotic strategy. The guidelines, however, disagree on many fundamental issues including:
the antithrombotic management of MHVRs in the first 3 months postoperatively. The AHA/ACC guidelines suggest that the postoperative use of unfractionated heparin (UFH) is controversial, whilst the ESC guidelines recommend its use;
the risk categorisation of different MHVRs;
the management of embolism in the presence of adequate anticoagulation;
the adjunct role of antiplatelets;
the bridging of anticoagulation interruption for non-cardiac surgery.
The challenging case of pregnancy in women with MHVRs also requires careful consideration.
Interruption of anticoagulation for non-cardiac surgery
The management of anticoagulant therapy (with vitamin K antagonists (VKAs)) in patients with MHVRs must be individualised. Anticoagulation should not be stopped for procedures in which bleeding is minimal or inconsequential—for example, surgery on the skin, many dental procedures and cataracts or glaucoma surgery. However, when bleeding is likely or may have severe potential complications, anticoagulation should be interrupted. If the patient is receiving antiplatelet(s) in addition, they should be discontinued (aspirin for 1 week and clopidogrel for 5 days) before the procedure.
Short periods of anticoagulation interruption do not usually lead to valve thrombosis/thromboembolic events (VT/TE). However, the highest risk period for TE in patients with MHVR is indeed after anticoagulation interruption. Short-term …