Prediction of cardiac events in pregnant women with cardiac diseases using modified WHO, CARPREG II, and ZAHARA risk assessments in southern Thailand.

Objective: This study aimed to compare the predictive performance of three cardiovascular risk assessment models-modified WHO (mWHO) classification, Cardiac Disease in Pregnancy II (CARPREG II), and Zwangerschap bij Aangeboren Hartafwijking (Pregnancy in Women with Congenital Heart Disease; ZAHARA)-in predicting cardiac events among pregnant women with cardiac diseases.

Methods: A retrospective review of medical records was conducted for all pregnant women with cardiac diseases who delivered at Songklanagarind Hospital between January 1, 2011, and December 31, 2022. Pregnancies ending in termination or miscarriage before 24 weeks were excluded. The mWHO, CARPREG II, and ZAHARA classifications were applied to each patient, with ZAHARA used only for congenital cardiac diseases. The discriminative ability of each model was evaluated using the area under the receiver operating characteristic curve (AUC).

Results: Among 333 pregnancies with cardiac diseases (163 congenital and 170 acquired), 100 (30.0%) experienced cardiac events. The AUCs for predicting cardiac events in all cases were 0.774 (95% confidence interval [CI] 0.719-0.826) for CARPREG II and 0.744 (95% CI 0.689-0.799) for mWHO. In acquired cardiac disease, the AUC for mWHO (0.700 [95% CI 0.621-0.779]) was higher than that for CARPREG II (0.677 [95% CI 0.596-0.758]). For congenital cardiac disease, CARPREG II exhibited the best predictive performance, followed by mWHO and ZAHARA, with AUC values of 0.768 (95% CI 0.658-0.877), 0.754 (95% CI 0.653-0.854), and 0.685 (95% CI 0.563-0.806), respectively.

Conclusion: CARPREG II demonstrated the highest predictive performance for cardiac events in pregnant women with all cardiac diseases, while ZAHARA exhibited the lowest predictive performance for congenital cardiac diseases.