Impact of Rheumatic Heart Disease on Maternal Outcomes
In sub-Saharan Africa, women face a 1 in 39 lifetime risk of dying during pregnancy, compared to the risk in the developed world of 1 in 3,800. New data indicates that in sub-Saharan Africa indirect, non-obstetrical causes account for over a third (34%) of these deaths.
In contrast to direct obstetrical deaths, which are steadily decreasing, indirect causes are on the rise. Indirect causes of maternal death include pre-existing conditions, such as cardiovascular disease, which are aggravated by the physiological effects of pregnancy. Rheumatic heart disease (RHD), which remains endemic in the developing world, is by far the most common cardiac diagnosis among pregnant women. Pregnancy represents a particularly vulnerable time for patients with RHD, as the hemodynamic burden and fluctuations of pregnancy and delivery can unmask or worsen rheumatic valvular disease, leading to devastating complications and loss of life.
A single study of women presenting to a tertiary center in Senegal reported a 34% maternal mortality rate among pregnant women with RHD. If these findings are replicated, then RHD would represent one of the primary drivers of indirect maternal death in sub-Saharan Africa. This is important as many RHD-related deaths, given sufficient warning and resources, could be prevented.
While extensive maternal mortality data has been gathered, these data are insufficient to determine the role of RHD in maternal mortality. Problems include (1) under ascertainment of cardiac diagnoses; (2) lack of detailed clinical data; (3) incomplete reporting of specific cause of death. Given these limitations, a prospective, population-based study is needed to appropriately evaluate the impact of the maternal RHD effect on maternal mortality.
To address this issue, we will capitalize on a unique opportunity to provide focused echocardiographic screening to primary health clinics in Uganda where ultrasound capabilities have previously been established through Imaging the World Africa (ITWA). ITWA relies on targeted ultrasound protocols and remote, cloud-based image interpretation to integrate universal antenatal ultrasound to identify obstetrical complications. The presence of ultrasound has enhanced participation in antenatal care (ANC). ITWA clinics now see 80% of pregnant women in the communities they serve. ITWA operates in 8 level III health clinics in Eastern, Central, and Western Uganda, 2 of which will serve as the basis for this project.
The clinics selected provide ANC to 1476 women each month, half of whom are presenting for initial evaluation. The team has extensive experience in echocardiographic screening for RHD in Uganda, having previously screened over 15,000 school aged children. The combination of this experience and the ITWA infrastructure provides a unique opportunity to capture representative population-based data on the impact of RHD in pregnancy.
We will use these resources to conduct a 2-year, prospective, observational study of 5000 women, including a nested cohort of RHD positive women, to test the hypothesis that RHD accounts for at least 10% of maternal deaths (percent population attributable risk of RHD) and that specific risk factors can be identified that predispose women to adverse outcomes.
We will address the following specific aims:
Aim 1: Determine the differential risk of maternal mortality among pregnant women with and without RHD, presented as relative and population attributable risk.
Aim 2: Evaluate the impact of specific risk factors (type, distribution, and severity of valvular heart disease, cardiac function, NYHA functional class, acute pulmonary edema, pulmonary hemorrhage, atrial fibrillation, and syncope) on maternal mortality among women with RHD.
Data from this study will directly lead to future studies developing referral/treatment algorithms aimed at preventing maternal morbidity and mortality from RHD.