The CARPREG Tool: Risk Assessment for Cardiac Disease in Pregnancy
The CARPREG (CARdiac disease in PREGnancy) tool is a validated risk prediction model that estimates the likelihood of adverse cardiac events in pregnant women with heart disease, with the most recent version (CARPREG II) incorporating 10 weighted predictors to stratify patients into risk categories ranging from 5% to 41% chance of cardiac complications. 1
CARPREG II Risk Prediction Model
The CARPREG II risk score assigns points to specific predictors:
High-Risk Factors (3 points each):
- Previous cardiac event or arrhythmia
- Baseline NYHA functional class III to IV or cyanosis
- Mechanical valve
Moderate-Risk Factors (2 points each):
- Ventricular dysfunction
- High-risk left-sided valve disease and LVOT obstruction
- Pulmonary hypertension
- Coronary artery disease
- High-risk aortopathy
Lower-Risk Factors (1 point each):
- No previous cardiac intervention
- Late pregnancy assessment
Risk Stratification:
| CARPREG II Score | Predicted Risk of Cardiac Events |
|---|---|
| 0 to 1 | 5% |
| 2 | 10% |
| 3 | 15% |
| 4 | 22% |
| >4 | 41% |
Clinical Application and Validation
The CARPREG II tool has demonstrated better discrimination and calibration than other risk assessment tools such as the modified WHO (mWHO), original CARPREG, and ZAHARA scores in predicting adverse cardiac events during pregnancy 1. It has high sensitivity and negative predictive value, making it particularly useful for identifying low-risk patients 2.
Primary cardiac events assessed by CARPREG II include:
- Maternal cardiac death
- Cardiac arrest
- Sustained arrhythmia requiring treatment
- Heart failure (left or right-sided)
- Stroke or TIA
- Cardiac thromboembolism
- Myocardial infarction
- Vascular dissection
Limitations and Considerations
Despite its utility, several studies have identified limitations:
- The tool may overestimate risk in certain populations and underestimate it in others 3
- Performance varies based on the underlying cardiac pathology, with some studies showing better performance in congenital heart disease than rheumatic heart disease 3
- In sub-Saharan Africa, where rheumatic heart disease predominates, both CARPREG and mWHO tools underestimated adverse cardiac events 4
- External validation in diverse populations is still needed to determine its generalizability 1
Clinical Implementation
For optimal outcomes, women with cardiac disease should:
- Undergo risk assessment using CARPREG II before conception
- Receive care from a multidisciplinary cardio-obstetric team throughout pregnancy
- Have hospital-based delivery with appropriate monitoring
- Receive close follow-up during the postpartum period (minimum 48 hours monitoring)
The CARPREG tool is particularly valuable for pre-pregnancy counseling, allowing clinicians to provide evidence-based risk estimates and guide decisions about pregnancy planning, management, and delivery 1, 5.
Evolution of CARPREG
The original CARPREG score has evolved to the more comprehensive CARPREG II, which includes lesion-specific and process-of-care predictors in addition to the historical and functional predictors from the original score 1. This evolution has improved the tool's predictive accuracy and clinical utility.
The CARPREG tool remains one of the most widely used and validated risk assessment instruments for pregnant women with cardiac disease, helping to reduce maternal morbidity and mortality through appropriate risk stratification and management.