Prediction of Adverse Outcomes during Pregnancy in Women with Congenital and Acquired Heart Disease

Introduction

Women with pre-existing cardiovascular disorders face significant challenges during pregnancy due to hemodynamic alterations. The incidence of congenital heart diseases (CHD) among reproductive-age women is rising, due to improved medical interventions in childhood and early adulthood. Cardiovascular events such as heart failure, arrhythmia and thromboembolic events are major contributors to maternal mortality, highlighting the need for comprehensive interdisciplinary care. Women with cardiovascular disease treated during their pregnancies at the University Hospital Freiburg in the last 10 years, were retrospectively analyzed. Here, we present the preliminary data from 168 cases focusing on differences between women with congenital heart disease (CHD) and those with acquired heart disease (AHD).

Results

Women with congenital heart disease tended to be younger with 31.4 years (IQR 27.7- 34.4)  vs. 33.0 years (IQR 30.0 - 36.3], p=0.056) and had a lower BMI at delivery (27.3 kg/m² [IQR 24.6 -31.2] vs. 28.4 kg/m² [25.1- 34.5], p=0.033). Gestational age was similar between groups (38.4 weeks [IQR 36.8 - 39.1] and 38.1 weeks [IQR 35.6-39.5] p=0.712). Cardiovascular risk factors were more prevalent in the AHD group, with 60.7% having at least one risk factor compared to 43% in the CHD group. CARPREG II scores were lower in CHD patients (1.71 vs. 3.36 in AHD), while mWHO scores were distributed similarly between the groups.  

Adverse cardiovascular events were significantly more frequent in the AHD group (27.9% [17/61] vs. 8.4% [9/106] in CHD, p< 0.01), as were obstetric complications. Gestational hypertension was diagnosed in 2.8% of CHD patients, versus 14.8% in AHD (p<0.01). Preterm delivery was also more common in AHD patients (32.8% vs. 13.1% in CHD, p< 0.01). Multivariable regression showed a 4.7-fold increased risk of cardiovascular events and a 1.96-fold increased risk of obstetric complications in women with AHD. Baseline NT-proBNP levels were significantly lower in CHD patients (168 ± 183 pg/mL) compared to AHD patients (550 ± 695 pg/mL), although BNP measurements were only available for approximately half of the patients. Left ventricular ejection fraction (LVEF) was normal in 90.7% of the CHD group but mildly or moderately reduced in 21.3% of AHD patients. For the CHD group mWHO score performed better in risk prediction, with an OR of 2.12 (CI 1.08-5.11, p< 0.05), whereas the CARPREG II score worked better in the AHD group with an OR of 1.30 (CI 1.06–1.62, p= 0.01).

Conclusion:

Our data suggests a higher occurrence of cardiovascular and obstetric complications during pregnancy in women with acquired heart disease compared to congenital heart disease, which is not indicated by published risk-scores. It further suggests that different risk prediction models might be necessary for CHD and AHD patients. The observed differences in out cohort might also be influenced by a higher disease burden in the AHD group, indicated by higher NT-proBNP level and LFEF categories.  Additionally, the pathophysiological changes leading to acquired heart disease may result in a cardiovascular system that is more vulnerable to the hemodynamic changes during pregnancy, thereby increasing the risk of complications. Further, the CHD group might profit from an often intensified surveillance and proactive management during pregnancy, leading to lower event rates and highlighting the importance of specialized interdisciplinary care.