Is there a suitable method of anticoagulation in pregnant patients with mechanical prosthetic heart valves?

Abstract

A best evidence topic was written according to a structured protocol in order to identify the mode of anticoagulation that has the best safety profile for both the mother and the foetus in pregnant patients with mechanical prosthetic heart valves. A total of 281 papers were identified using the reported search, of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. The reported measures were foetal mortality, maternal mortality, congenital abnormalities and embryopathy, and maternal thromboembolic and haemorrhagic complications. The medical orthodoxy has warned of the combination of oral anticoagulation and pregnancy due to the well-documented warfarin embryopathy. Yet only one of the reported papers identified a greater incidence of foetal aberrations among warfarin use, with the highest reported rate being 6.4% and two of the assessed papers reporting no embryopathy at all. Foetal mortality with oral anticoagulation use ranged from 1.52 to 76%. All reported publications demonstrated a superior maternal outcome with warfarin use, with a range of thromboembolic events from 0 to 10% in comparison with 4 to 48% where heparin was used. Thus, it is concluded that warfarin is a more durable anticoagulant with a better maternal outcome despite it carrying a greater foetal risk. Although, in contrast to previous teaching, the risks of embryopathy are not the major drawback of oral anticoagulation. Heparin is consistently less effective, but may be preferred for the superior foetal outcome. Heparin usage during the first trimester reduces the foetal risk but is still associated with an adverse maternal outcome. While the focus for clinicians looking after pregnant women with mechanical heart valves may be to prevent maternal thromboembolic complications, the overriding concern for many women is to avoid any harm to their unborn child, even when this places their health at risk. Thus women with mechanical heart valves must be fully informed of the risks involved with different anticoagulation for an informed decision to be made.

Clinical outcomes of pregnant women with mechanical heart valves

“…Mekanik kalp kapağı protezi olan gebe hastalardaki antikoagülan tedavi seçimi, elimizde mevcut olan tüm [1,2] Dolayısıyla bu hasta grubunun takibinde bu ilaçların tek başına veya gebeliğin farklı dönemlerinde kombine kullanımını öneren farklı tedavi şemaları önerilmiştir. [1][2][3][4] Oral antikoagülanlar, anneyi ve kapağı korumada en güvendiğimiz ilaçlardır ancak bu ilaçlar bebekte embriyopati oluşturma potansiyeline sahiptir.…”

“…[1][2][3][4] Oral antikoagülanlar, anneyi ve kapağı korumada en güvendiğimiz ilaçlardır ancak bu ilaçlar bebekte embriyopati oluşturma potansiyeline sahiptir. Plasentayı geçebilir ve ilk trimesterde kullanıldığında klasik olarak varfarin embriyopatisi denilen fetal anomalilere yol açabilir.…”

“…Heparin türevlerinin kullanımı da tartışmalıdır çünkü daha iyi fetal sonuçlara sahip olmasına rağmen mekanik kalp kapaklı anneyi tromboembolik komplikasyonlardan korumada yetersiz kalabilmektedir. [1,2] Oral antikoagülanların da heparin türevlerinin de riskleri olduğu için, hem anne hem de bebek için belirlenebilmiş etkili ve güvenli bir antikoagülasyon rejimi bulunmamaktadır. Bu nedenle bu hastaların nasıl tedavi edilebileceği zor bir ikilemdir ve mutlaka hasta ve hasta yakınlarına ayrıntılı bilgi verilerek birlikte karar verilmelidir.…”

Antithrombotic Therapy in Patients Postcardiac Interventions

“…In first and third trimester, patients may be switched to heparin, 3 unfractionated heparin (UFH) or low molecular weight heparin (LMWH). There is added risk to fetus if oral anticoagulation is continued in first trimester.…”

“…Some clinicians advocate continuation of oral anticoagulation till the time of delivery when patient is switched to heparin. 3 Child birth can be managed in a fashion similar to the protocol for elective surgery noted above.…”