Abstract Body (Do not enter title and authors here): Introduction: The US maternal mortality rate is rising, with cardiovascular disease being the main cause of death. Acute myocardial infarction in particular (most commonly ST-elevation myocardial infarction (STEMI)) is associated with excess mortality. There have been no recent large, population-based studies estimating the current incidence of postpartum STEMI or identifying its risk factors.
Research Question: Given the increasing risk of postpartum STEMI and the consequences of such a diagnosis we sought to identify recent incidence of postpartum STEMI and understand its predictors.
Goal: The purpose of this study was to describe the incidence and risk factors of acute postpartum STEMI in the USA.
Methods: This study was performed using MarketScan Commercial Claims and Encounters Data. Patient selection was from all deliveries resulting in a live birth between 2017 and 2020 with claims data available for 12 months prior and 6 months following delivery data. For all births, STEMI within 6 months was noted and the following risk factors were collected: age, hypertension (HTN), thrombophilia, anemia, diabetes mellitus (DM), and smoking. We then performed multivariate logistic regression models to estimate odds ratio (95% confidence interval) for STEMI adjusted for the aforementioned risk factors.
Results: 327,570 delivery cases were identified, of which 3330 (1%) had a STEMI in the time from hospital admission to 6 months postpartum. Most STEMIs occurred close to the time of delivery: 2823 (84.8%) cases within 24 hours of delivery and an additional 132 within 1 week, 80 within 2 weeks, and 52 within 4 weeks (cumulative totals of 89.4%, 91.8%, and 93.3% respectively). The following factors had a significant, independent, positive correlation with STEMI: age ≥40 (OR 1.6 [95% CI 1.4-1.9]), DM (OR 1.6 [95% CI 1.5-1.7]), HTN (OR 1.6 [95% CI 1.5-1.7]), and smoking (OR 1.5 [95% CI 1.3-1.8]). These are shown in Figure 1.
Conclusion: Although rare, postpartum STEMI is associated with high morbidity and mortality and is occurring at an increasing rate. While maternal age is not modifiable, HTN, smoking and DM are, and more should be done to address these risk factors in those who are, or plan to become, pregnant.