A clinical conundrum: review of anticoagulation in pregnant women with mechanical prosthetic heart valves

Abstract

In South Africa, maternal mortality from cardiovascular disease remains high. The recent Saving Mothers report 2017-2019 from the Confidential Enquiries into Maternal Deaths revealed that indirect maternal death from medical and surgical disorders is the fourth commonest cause of maternal death, accounting for 16.9% of deaths, with cardiac disease accounting for one-third of this. The burden of rheumatic heart disease (RHD) is a significant contributor to maternal morbidity and mortality. The true burden is unknown due to limited data. The natural history of RHD confers additional risk as many cases may remain undiagnosed, with first presentation occurring during pregnancy. This undiagnosed subset of women may be the result of poor accessibility to healthcare facilities and primary healthcare interventions for acute rheumatic fever. RHD causes progressive damage to the heart valves, especially the left-sided valves, which eventually require surgical correction with mechanical prosthetic valves.

Keywords: bio‐prosthetic heart valves; heparin; mechanical heart valves; pregnancy; rheumatic heart disease; warfarin.

Fig. 1

Difference in mode of action of UFH and LMWH.

Fig. 2

Mode of action of warfarin.

Fig. 3

What the international guidelines say.

Fig. 4

Anticoagulation regimens used in pregnancy at Inkosi Albert Luthuli Central Hospital high-risk unit using warfarin, UFH and LMWH.

Fig. 5

Author recommendations for anticoagulation in pregnant women with mechanical heart valves at Inkosi Albert Luthuli Central Durban, South Africa.

Fig. 6

Complications that can occur in the antenatal and peripartum periods.