Open Access

ARTICLE

Accuracy of risk prediction scores in pregnant women with congenital heart disease

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1 Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
2 Division of Cardiology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
3 Maternal and Child Health Research Center, Department of Obstetrics and Gynecology, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania
4 Biostatistics and Data Management Core, The Children’s Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania

* Corresponding Author: Yuli Y. Kim MD, Philadelphia Adult Congenital Heart Center Penn Medicine & The Children’s Hospital of Philadelphia, 3400 Civic Center Boulevard, PCAM 2nd Floor E. Pavilion Philadelphia, PA 19104. Email:

Congenital Heart Disease 2019, 14(3), 470-478. https://doi.org/10.1111/chd.12750

Abstract

Objective: To assess performance of risk stratification schemes in predicting adverse cardiac outcomes in pregnant women with congenital heart disease (CHD) and to compare these schemes to clinical factors alone.
Design: Single‐center retrospective study.
Setting: Tertiary care academic hospital.
Patients: Women ≥18 years with International Classification of Diseases, Ninth Revision, Clinical Modification codes indicating CHD who delivered between 1998 and 2014. CARPREG I and ZAHARA risk scores and modified World Health Organization (WHO) criteria were applied to each woman.
Outcome Measures: The primary outcome was defined by ≥1 of the following: arrhyth‐ mia, heart failure/pulmonary edema, transient ischemic attack, stroke, dissection, myo‐ cardial infarction, cardiac arrest, death during gestation and up to 6 months postpartum.
Results: Of 178 women, the most common CHD lesions were congenital aortic ste‐ nosis (15.2%), ventricular septal defect (13.5%), atrial septal defect (12.9%), and te‐ tralogy of Fallot (12.9%). Thirty‐five women (19.7%) sustained 39 cardiac events. Observed vs expected event rates were 9.9% vs 5% (P = .02) for CARPREG I score 0 and 26.1% vs 7.5% (P < .001) for ZAHARA scores 0.51‐1.5. ZAHARA outperformed CARPREG I at predicting adverse cardiovascular outcomes (AUC 0.80 vs 0.72, P = .03) but was not significantly better than modified WHO. Clinical predictors of adverse cardiac event were symptoms (P = .002), systemic ventricular dysfunction (P < .001), and subpulmonary ventricular dysfunction (P = .03) with an AUC 0.83 comparable to ZAHARA (P = .66).
Conclusions: CARPREG I and ZAHARA scores underestimate cardiac risk for lower risk pregnancies in these women. Of the three risk schemes, CARPREG I performed least well in predictive capacity. Clinical factors specific to the population studied are comparable to stratification schemes.

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