Risk assessment using DEVI and CARPREG -1 score to predict maternal adverse cardiac cvents in pregnancies with valvular heart disease: external validation study from MPAC registry

Abstract Background Even though many risk assessment tools in pregnant women with valvular heart disease (VHD) are available, validation studies are few that assess their performance in diverse settings, which is needed prior to the application of routine clinical practice. Objectives To validate and establish the clinical utility of two risk stratification tools – DEVI (VHD-specific tool) and CARPREG-I in predicting adverse cardiac events in pregnant patients with VHD. Methods This cohort study involved consecutive pregnancies complicated with VHD enrolled in the prospective MPAC registry from July 2016 to December 2019(1). The ability to discriminate those with and without adverse cardiac outcomes was assessed using the area under the curve for both the DEVI and CARPREG-1 scores. Performance was assessed through discrimination and calibration characteristics. Clinical utility was evaluated with Decision Curve Analysis. Results Among 1029 pregnancies complicated with heart disease in the MPAC registry cohort, 604(52.3%) with valvular heart disease were included in this analysis. One or more composite adverse cardiac events occurred in 70 (11.6%) pregnancies during antenatal or the early postpartum period. Mitral regurgitation was the most common lesion (67.7%). In assessing the pregnancy outcomes, those who continued past 20 weeks were included, with the majority (92.0%) delivered at term, and the cesarean rates were 33.6% (n=203). The most common adverse event was heart failure (n=32, 5.3%), most of which (68.6%) occurred in the postnatal period. There were 11 maternal deaths (1.8%) during the study period, six among those with mechanical heart valves (four prosthetic valve thrombosis), two among those with severe mitral stenosis and pulmonary hypertension and two with severe mitral regurgitation and infective endocarditis. The area under the receiver operating characteristic curve (AUC) was 0.766, with 95% confidence intervals (CI) 0.703- 0.828 for DEVI and 0.703 (95%CI 0.644- 0.763) for CARPREG-I models. Calibration plots suggested that the DEVI score overestimates risk at higher probabilities, whereas the CARPREG-I score underestimates the risk at most probabilities. Decision curve analysis demonstrated that both models were useful across predicted probability thresholds between 10% and 60%. Conclusion In this external validation study in pregnant women with primary rheumatic VHD, DEVI and CARPREG-I scores showed good discrimination ability and clinical utility across various probabilities. Both can be used to classify those who develop adverse cardiac outcomes during pregnancy and childbirth. However, both models need recalibration to improve the agreement between the predicted and observed events prior to routine application in diverse clinical settings.Figure 1.a and b ROC and Decision Curves