Ventricular-Arterial Coupling in Maternal Heart Disease and Its Association with Fetal and Uteroplacental Outcomes in the Mid-trimester of Pregnancy

• Author / Creator

  Lasso Mendez, Juliana

• Background: Maternal heart disease (MHD) or heart disease during pregnancy, which can be congenital (CHD) or acquired (AHD), affects 4% of all pregnancies and is associated with increased maternal and fetal complications. Some have proposed cardiac dysfunction to be responsible for these complications. However, not all MHD pregnancies with maternal or fetal complications have significant cardiac dysfunction suggesting that other factors could be contributory. Vascular health has been seen to be affected in non-pregnant populations with CHD and complicated pregnancies without MHD. Therefore, we chose to examine ventricular-arterial coupling (VAC), a measure of cardiovascular function which incorporates both vascular load and left ventricular (LV) efficiency/function in MHD and control participants. An increase in VAC will either suggest increased arterial load, decreased LV efficiency or a combination. Therefore, as we chose to focus on cardiac health, we hypothesized that VAC would be increased in MHD, at least partly due to reduced LV efficiency or function. We also hypothesized that increased VAC would be associated with poor uteroplacental and fetal health in the midtrimester of pregnancy. 

  Methods: Participants with and without MHD were recruited between 18-24 weeks of gestation (midtrimester) to undergo transthoracic and fetal echocardiography. Groups were matched by maternal age, pre-pregnancy body mass index and body surface area. Metrics of cardiovascular function including VAC, cardiac output (CO), LV ejection fraction (LVEF), global longitudinal strain and E/E’ were obtained by thoracic echocardiography. VAC was calculated as arterial elastance (Ea)/end-systolic elastance (Ees) using LV volumes and LVEF, blood pressure and the preejection/total systolic period. Fetal biometry and Doppler-based uterine (UtA) and umbilical (UA) artery pulsatility indices (PI) were assessed by fetal echocardiography with comparisons made in centiles. Depending on the normality of the distribution of a given outcome, independent samples t-test or a Mann-Whitney U statistical test were used to compare outcomes between MHD and control participants. One-way ANOVA or a Kruskal-Wallis test for nonparametric data were used to compare outcomes between severity of MHD (mild or moderate-severe) and controls. 

  Results: We recruited 33 MHD (29 CHD , 4 AHD, mean 20.0±1.2 weeks gestation) and 32 control (21.5±1.6 weeks) pregnancies. Maternal heart rate and blood pressures did not differ among groups. VAC was higher in MHD compared to controls (0.78±0.15 vs 0.69±0.01, p=0.0063), with highest values in those with moderate-severe HD (0.80±0.18 vs controls, p=0.009), suggesting reduced cardiac function or increased arterial load in MHD. Reduced cardiac function was supported by a lower Ees in MHD, reflecting reduced LV efficiency/function. Although CO, global longitudinal strain and strain rate did not differ, other measures of cardiac function were affected in MHD including LVEF and E/E’. LVEF was significantly reduced in MHD vs controls (61±9% vs 67±6%, p=0.0033) and E/E’ higher (median [IQR]: 7.1 [3.7] vs 5.8 [1.9], p=0.015), especially in those with moderate-severe HD. Finally, UtA-PI, UA PI and fetal biometry were similar among groups , however, 10% of MHD vs 0% of controls had a UtA-PI >95th centile.

  Conclusion: Increased VAC in MHD could suggest the presence of reduced LV function, increased arterial load or both in affected pregnancies. Reduced absolute Ees, and LVEF and increased E/E’ indicate reduced cardiac function in MHD, possibly contributing to increased VAC. Uteroplacental and fetal health are preserved at this point in pregnancy despite increased VAC in MHD.

• Subjects / Keywords

  • Pregnancy
  • Heart disease

• Graduation date

  Fall 2024

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-1hab-9k60

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.