Abstract Body (Do not enter title and authors here): Introduction: Impaired nitric oxide-mediated coronary endothelial function (CEF) is a predictor of future cardiovascular (CV) events and may be impaired in women with preeclampsia (PEC). However, the contributing factors to impaired CEF—such as perceived stress, which is common in women with PEC—are not well understood. This study aimed to compare CEF in postpartum women with and without a history of PEC and to test the hypothesis that higher levels of perceived stress may associate with impaired CEF in women with a history of PEC.

Methods: Postpartum women with and without a history of PEC were prospectively enrolled. Cardiac MRI was used to measure nitric oxide-mediated CEF as the change in cross-sectional coronary area, coronary flow, and coronary velocity in response to isometric handgrip exercise using previously validated methods. Perceived external stress was assessed on the day of the imaging visit using the validated Perceived Stress Scale (PSS). Between-group comparisons were assessed using the Chi-Square test or Fisher’s exact test for categorical variables and the Mann-Whitney U test or t-test for continuous variables. The association of CEF and PSS in women with PEC was assessed using Spearman’s correlation coefficient and adjusted linear regression.

Results: Of 85 postpartum women, 42 had a recent history of PEC and 43 did not. Median age was 32 (IQR 30-36) and median time postpartum was 22 (IQR 16-29) weeks. In the PEC group, women had higher BMI but lower rates of type 2 diabetes, and were otherwise age and race matched with controls. Women with PEC had impaired CEF as reflected by lower exercise-induced changes in coronary area and coronary flow (Figures 1A and 1B). PEC remained a significant predictor of impaired CEF after adjusting for diabetes and BMI. In women with a history of PEC, higher PSS scores were associated with lower exercise-induced changes in coronary area (Fig 2A) and velocity (Fig 2C). Higher PSS remained a significant predictor of a lower change in coronary area (β=-0.53, p=0.045) but not coronary velocity after adjusting for age and race.

Conclusion: Women with PEC showed impaired nitric oxide-mediated CEF in the postpartum period, which is associated with increased CV risk. Higher perceived stress may associate with impaired CEF in women with PEC. These findings help understand the physiology behind increased CV risk in postpartum women with PEC and may suggest new risk stratification and reduction strategies.