Mechanical Heart Valves in Pregnancy

Anticoagulation for the Pregnant Patient with a Mechanical Heart Valve, No Perfect Therapy: Review of Guidelines for Anticoagulation in the Pregnant Patient

“…Although warfarin can pose a threat to the fetus at any point in the pregnancy, the fetus is most vulnerable to teratogenic effects during the first trimester. Previous case series have proven the embryopathy rate to be as high as 5 to 7% to those exposed to warfarin in the first trimester [ 7 ]. Some literature does suggest that these effects are dose dependent and that daily doses less than 5 mg/day appear to significantly reduce the risks of fetal toxicity [ 8 , 9 ].…”

Anticoagulation in pregnancy and puerperium: With a focus on the benefits and risks of the applications of vitamin K antagonists on the prevention of mechanical heart valves thrombosis

“…If the required warfarin dose is greater than 5 mg, then switch between 6-12 weeks from VKA to treatment with iv infusions UFH or LMWH s.c. with a one-week control of anti-Xa levels (a target value of 0.8-1.2 U/ml in the blood sample taken 4-6 hours after injection) Table 3. The recommendations and the various modalities of administering parenteral anticoagulants and vitamin K antagonists during pregnancy in patients with mechanical heart valves compared with the warfarin dose needed to achieve a therapeutic INR [1,7,33] U/ml in the blood sample taken 4-6 hours after injection [23,34]. Trough levels of anti-Xa activity, so-called pre-dose levels are not yet suffi ciently harmonized, especially with regard to the relationship between thromboembolism and hemorrhage, for any fi rm conclusions to be reached, but for the time being it is considered that they should be higher than 0,6 U/mL [1].…”

“…Th e administration of heparin products between 6 and 12 weeks of pregnancy does not lead to teratogenicity, but such a therapeutic approach entails a much higher risk of thromboembolic complications of 9.2%, noting that the use of UFH in adequate doses recommended for valve thrombosis prophylaxis does not absolutely prevent valve thrombosis occurring as well as the fact that there is also a risk of considerable variation of aPTT levels along with a chance of bleeding, even intracranial hemorrhage [7,8,19].…”

“…A series of homeostatic changes induced in pregnancy is associated with activated protein C resistance registered in a number of pregnant women [3][4][5]. Also, there is an increase in platelet-endothelial adhesion molecules as well as endothelial cell activation associated with a proinfl ammatory state, especially during labour or caesarean section when damage to blood vessels is incurred [2,6,7].…”

The MITRIS RESILIA mitral valve is a safe and effective option for mitral valve replacement in young patients requiring mitral valve replacement

“…This is increasingly problematic in female patients who desire to become pregnant, given that the only approved oral anticoagulant is Warfarin, a known teratogen. 4 Additionally, mechanical valve re-replacement rates are higher in paediatric populations, with reported rates in excess of 25%. 5 The other option for valve replacement is bioprosthetic valves.…”