What is the perioperative medication management of heart valve prostheses?

Updated: Jan 09, 2018
  • Author: Nafisa K Kuwajerwala, MD; Chief Editor: William A Schwer, MD  more...
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Answer

Answer

For those patients with heart valve prostheses, anticoagulant management is an important component of perioperative care. [7]

For major surgeries, substituting warfarin with heparin is recommended to maintain anticoagulation until the time of surgery. The short half-life of heparin allows the patient to safely undergo surgery within a few hours after discontinuation. Heparin should be discontinued 6 hours prior to surgery and then restarted 12-24 hours after surgery, when postoperative hemorrhage is no longer a threat. Monitor heparin by maintaining an activated partial thromboplastin time (aPTT) of 1.5- to 2-times normal. For patients on warfarin, checking the prothrombin time 1 day prior to the day of the operation and administering vitamin K (1-3 mg is generally sufficient), if necessary, is recommended.

Therapeutic anticoagulation is typically not reestablished for several days after warfarin is initiated; therefore, the patient should again receive heparin in the postoperative period until oral anticoagulation is fully therapeutic. Start warfarin and adjust to an International Normalized Ratio (INR) based on the underlying reason for the long-term anticoagulation.

For minor surgery (eg, cataract removal, most dental surgeries), Coumadin does not need to be discontinued, although many surgeons still request it.

When substituting warfarin with heparin, low molecular weight heparin (LMWH) generally can be used. Widespread anecdotal experience among cardiologists and internists suggests that Lovenox in a dose of 1 mg/kg bid can be used safely instead of unfractionated heparin, but double-blind studies have not been conducted. The exception to this is prosthetic valves requiring an INR of 3-3.5. Because of the lack of experience with LMWH in this setting, conventional heparin should still be used.

When using LMWH, the last dose should be 12 hours before surgery. However, if spinal anesthesia is anticipated, the last dose should be 24 hours before surgery.

For patients taking warfarin for atrial fibrillation, warfarin can be stopped safely without interim use of heparin. The exception to this is the high-risk patient with atrial fibrillation (eg, history of prior embolization, known atrial thrombus).


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