Role of prenatal cardiovascular magnetic resonance imaging in determining pregnancy risk in repaired Tetralogy of Fallot patients

Funding Acknowledgements

Type of funding sources: None.

Addressing pregnancy risks poses as a new challenge among women with repaired tetralogy of Fallot (TOF). The high-output state of pregnancy may predispose women to late complications of repaired TOF. However, guidelines regarding antenatal and or perinatal cardiovascular assessment has not been outlined. Noninvasive modalities such as cardiac magnetic resonance imaging (CMR) that do not require the utilization of ionizing radiation are feasible methods of assessment. Risk stratification of baseline CMR parameters has been sparsely investigated among repaired TOF cohorts. This study aims to identify baseline CMR parameters that may predict adverse outcomes of pregnancy among women with repaired TOF.

Sixty-five successful pregnancies were recorded from a cohort of 105 pregnant episodes. Patients with CMR studies performed within 5 years prior to delivery events were included. Adverse clinical outcomes of interest included arrhythmia, heart failure admissions, gestational hypertension, pre-eclampsia toxemia and all-cause mortality. Baseline CMR parameters regarding ventricular mechanics such as left and right ventricular end-diastolic and end-systolic volumes, left and right ventricular ejection fractions and pulmonary regurgitant fraction were measured, and their association with adverse clinical outcomes were evaluated using an independent-samples t-test.

Within all 65 successful pregnancies, 26 baseline CMR images were obtained and included in this study. The mean maternal age was 29.7 ± 6.7 years old with a mean birth weight of 2.91 ± 0.49 kg at a mean gestational age of 38.4 ± 2.0 weeks. There was a total of 12 patients with adverse clinical outcome: 5 patients with heart failure hospitalizations, 4 patients with gestational hypertension, 4 patients with arrhythmia and 2 patients with pre-eclampsia toxemia.

Assessment of baseline CMR parameters of ventricular mechanics revealed that increased left ventricular end-diastolic volumes (LVEDV) (144.7mL/m2 ± 4.9; P = 0.011), left ventricular end-systolic volumes (LVESV) (65.1mL/m2 ± 9.4; P = 0.004), right ventricular end-diastolic volumes (RVEDV) (235.2 ± 29.0; P = 0.021) and right ventricular end-systolic volumes (RVESV) (122.2mL/m2 ± 38.1; P = 0.033) were associated with an increased incidence of arrhythmia during pregnancy. Nonetheless, there was no significant association between baseline ventricular mechanics with heart failure, gestational hypertension, and pre-eclampsia toxemia. 

Baseline assessment of cardiac magnetic resonance imaging among pregnant TOF women revealed that larger left and right ventricular volumes were associated with arrythmia development during pregnancy. Further studies with larger cohort sizes evaluating the role of antenatal and perinatal cardiovascular imaging assessment using CMR in predicting the risks of cardiovascular complications during pregnancy are warranted.

Serial echocardiography assessment and clinical outcomes among pregnant women with Tetralogy of Fallot

Funding Acknowledgements

Type of funding sources: None.

Following advancements in intracardiac repair of Tetralogy of Fallot (TOF), a greater proportion of patients survive well beyond child-bearing age. Pulmonary regurgitation (PR) and subsequent progressive right ventricular dilatation occur frequently as an intrinsic complication of surgical repair of TOF. High-output states such as pregnancy may exacerbate these late complications. The advocation of pre-pregnancy pulmonary valve replacement to mitigate pregnancy-related cardiac burden has remained controversial. This study aims to delineate the outcomes of pregnancy among women with repaired TOF.

105 pregnant episodes among were identified from a cohort of 240 adult female patients with TOF between 1990 to 2021. Patients with echocardiographic studies performed within 1 year prior to and following delivery were included for cardiac functional analysis. A paired sample t-test was performed to compare echocardiographic parameters between pre-delivery and post-delivery periods. Linear regression was used to identify changes to identify significant changes in echocardiographic parameters among patients with a baseline of severe PR.

Within all pregnant episodes (n = 105), 65 successful pregnancies, 16 spontaneous miscarriages, 21 termination of pregnancies and 3 ectopic pregnancies were recorded. The mean maternal age was 28.9 (±6.7) years with deliveries at 37.86 (30-41) gestational weeks. Cardiovascular events occurred in 19 pregnancies with 4 patients having gestational hypertension, 4 patients with pre-eclampsia toxemia, 7 patients with heart failure symptoms and 4 patients with arrhythmias. Other complications included 4 patients with gestational diabetes mellitus, 3 patients with impaired glucose tolerance, 2 patients with anemia, 3 patients with maternal thyroid disease and 1 patients with proteinuria.

Echocardiographic studies demonstrated significant changes in left ventricular ejection fraction (LVEF) (Pre-delivery = 60.69 ±8.73; post-delivery = 59.39 ±9.36) (P = 0.007), left ventricular end diastolic volume (LVEDV) (Pre-delivery: 89.71mL ±18.22mL; Post-delivery: 80.96mL ±12.32mL; P = 0.007), left end systolic volume (LVESV) (Pre-delivery: 35.43 ±12.36; Post-delivery: 32.70 ± 8.83; P = 3.7x10-5) and right ventricular index of myocardial performance score (Pre-delivery: 0.34 ±0.12; Post-delivery: 0.33 ±0.12; P = 0.007). Patients with severe PR was found to have significantly worse right ventricular global longitudinal strain (RV GLS) (P = 0.029). 2 patients progressed to severe PR following delivery.

Adult female patients with TOF can have viable pregnancies with acceptable mortality and morbidity. Deterioration in echocardiographic parameters were identified when comparing between pre-delivery and post-delivery studies. TOF patients should be closely monitored throughout and post-delivery for detection of deterioration of cardiac function and clinical symptoms.