Anticoagulación en gestantes portadoras de prótesis mecánicas

Objective

To study distinct anticoagulation regimens in pregnant women with prosthetic heart valves.

Subjects and methods

We performed a systematic review of the literature to determine the required levels of anticoagulation prophylaxis, timing of the introduction of oral anticoagulation and its substitution by heparins, and the maternal and fetal risks associated with different anticoagulation regimens.

Results

A target international normalized ratio (INR) of 2.5-3.5 should be achieved. Although consensus on the heparin of choice is lacking, heparin dose requirements should be based on anti-factor Xa levels (around 1.0 U/mL) or activated partial thromboplastin time (aPTT) (2-3 times control value). The risk of thrombosis in heparin-treated patients is approximately 7%, while the incidence of heparin embryopathy ranges from 1.6-7.4%. The switch from oral anticoagulation to heparin should be made no later than at weeks 35-36 of pregnancy.

Conclusions

The nticoagulation therapy of choice in the first trimester of pregnancy cannot currently be established. Prospective and randomized studies are required to determine the advisability of one treatment over the other