VALVE PROSTHESIS
Stopping AnticoagulatioN
With the use of antiplatelet agents (especially with bileaflet valve prostheses), patients not taking chronic anticoagulation have an increased incidence of valve thrombosis but with minor increase in the incidence of TE has been reported
Following Anticoagulation Related Haemorrhage (ARH) episodes:
There is a high incidence of recurrent bleeding, therefore:
If anticoagulant therapy cannot be restarted:
There is a high incidence of recurrent bleeding, therefore:
- Anticoagulant is withheld up to 2 weeks or until the bleeding source has been treated.
- Antiplatelet agents are used instead.
If anticoagulant therapy cannot be restarted:
- Continue with antiplatelet therapy indefinitely
- warn the patient of increased incidence of:
- Thromboembolism 4% per patient-year, and
- Valve thrombosis 2% per patient-year with bileaflet valves
Reversal of Anticoagulation for Elective Procedure:
Anticoagulation is restarted after the procedure:
- INR is allowed to drift slowly toward normal over 5 days
- Patient is admitted for IV heparin 24 hours prior to the procedure.
Anticoagulation is restarted after the procedure:
- Anti- platelet therapy, and SC heparin with warfarin restarted on postoperative day one:
WARFARIN COMPLICATIONS:
- Bleeding:
- Risk increased 4 to 8 times when PT >2.5 normal control or INR >5
- GI Bleeding is the most common and more in patients with previous GI disorder:
- Peptic ulcer, gastritis.
- GI lesions
- Cancer
- Hypertension
- Skin Necrosis:
- Caused by hypercoagulable state in the capillaries induced by a fall in Protein C concentration before effective warfarin inhibition for factor II, IX, X.
- Protein C is a natural vitamin K dependant warfarin sensitive anticoagulant.
- Activated Protein C is a powerful inactivator of factor V and VIII.
- Reasons that necrosis limited to the skin is not known.
- Pregnancy Related:
- Embryopathy: 4-8% during 1st trimester.
- CNS abnormalities: 3% during 2nd and 3rd trimester.
- Prematurity.
- Fetal haemorrhage.
- Stillbirth.