Pregnancy with a prosthetic heart valve, thrombosis, and bleeding: the ESC EORP Registry of Pregnancy and Cardiac disease III.

Summary

In this global prospective registry of 613 pregnancies with prosthetic valves, biological valves had higher chances of uncomplicated live birth than mechanical valves (79% vs 54%). LMWH-based regimens were associated with more thromboembolic/hemorrhagic complications, valve thrombosis occurred in 6%, and mitral position strongly predicted thrombosis; anti-Xa monitoring benefits were inconclusive.

Key Findings

• Uncomplicated live birth was 54% with mechanical valves vs 79% with biological valves (P < .001).
• LMWH-based regimens had the highest rates of thromboembolic and hemorrhagic complications; overall valve thrombosis occurred in 6%.
• Mitral mechanical valve position predicted valve thrombosis (OR 3.3; 95% CI 1.9–8.0); anti-Xa monitoring benefits on events were inconclusive (P=0.060).

Clinical Implications

For women anticipating pregnancy, biological valves yield more favorable outcomes. In mechanical valves, particularly in the mitral position, LMWH-based regimens appear to carry higher thromboembolic/bleeding risks; careful regimen selection, shared decision-making, and close monitoring are warranted.

Limitations

• Observational design with potential confounding by indication; not randomized
• Anti-Xa monitoring analysis underpowered for definitive benefit assessment

Future Directions

Randomized or carefully controlled comparative studies of anticoagulation strategies in mechanical valve pregnancy, with standardized anti-Xa protocols and valve-position–specific risk stratification.