Comparison of 3 Risk Estimation Methods for Predicting Cardiac Outcomes in Pregnant Women With Congenital Heart Disease

Background: Three risk estimation methods for predicting the cardiac outcomes of pregnancy in women with heart disease have been proposed. This study was designed to compare their prediction performance in an Asian cohort with congenital heart disease (CHD). Methods and Results: This study enrolled pregnant women with CHD who delivered their babies after the 20th gestational week between 1985 and 2011. Of 268 pregnancies in 190 women with CHD, 18 (6.7%) had cardiac complications. The incidence of maternal cardiac events among women with a CARPREG index of 0, 1 or 2 was 3.4%, 27.3% and 100%. The incidence was 2.7%, 8.6%, 11.1%, 40% and 17.6% for those with a ZAHARA score 0-0.5, 0.51-1.5, 1.51-2.5, 2.51-3.5 and >3.5. Among patients with a modified World Health Organization (WHO) classification I, II, III and IV, the incidence of maternal cardiac events was 0%, 4.0%, 12.2% and 25.7%. The c-statistic was 0.732 (95% confidence interval (CI): 0.589, 0.876; P<0.001) for the CARPREG score, 0.737 (95% CI: 0.611, 0.864; P=0.001) for the ZAHARA score and 0.827 (95% CI: 0.745, 0.909; P<0.001) for the WHO classification. Conclusions: All 3 risk estimation methods had good performance in predicting maternal cardiac outcomes; however, the modified WHO classification demonstrated superior discrimination and calibration.