Abstract Body (Do not enter title and authors here): Background:
Hypertensive disorders of pregnancy (HDP) elevate the risk of cardiovascular complications during and after delivery, contributing to both short-term morbidity and long-term disease burden. Identifying factors linked to acute cardiac events at delivery is essential for improving outcomes, particularly in high-risk populations.

Methods:
We conducted a retrospective cohort study using the Vizient® Clinical Data Base (01/2022-03/2025) to identify delivery hospitalizations with HDP. Acute cardiac complications were defined using ICD-10-CM codes and included acute heart failure, arrhythmia, peripartum cardiomyopathy (PPCM), and myocardial infarction (MI). Multivariable logistic regressions adjusted for age, race, ethnicity, payer, gestational diabetes mellitus (GDM), cesarean delivery, and Vizient Vulnerability Index™ (VVI; leveraged to examine ZIP-code level vulnerability correlated to life expectancy across 9 domains) were utilized. Descriptive analyses assessed length of stay (LOS), ICU use, and in-hospital mortality. Data from the Vizient Clinical Data Base were used with the permission of Vizient (all rights reserved).

Results:
Among 991,023 HDP-related deliveries, 0.92% had a cardiac complication. Arrhythmia (67%) and acute heart failure (30%) were most common, followed by PPCM (11.6%) and MI (3.5%). Increasing age was associated with higher odds of cardiac complications, particularly for heart failure (aOR 1.08; 95%CI: 1.08-1.09) and MI (aOR 1.06; 95%CI: 1.04-1.08). Cesarean delivery showed strong associations across all outcomes, highest for MI (aOR 3.95; 95% CI: 3.05-5.11). Black race was linked to heart failure (aOR 1.60; 95%CI: 1.47-1.76) and PPCM (aOR 1.29; 95%CI: 1.12-1.50). High social vulnerability, as measured by the VVI, was consistently associated with elevated risk (aORs 1.45-2.36), compared to low VVI. Hispanic ethnicity was associated with lower odds (aORs 0.41-0.59), and GDM was not associated with increased risk. Cardiac events were linked to longer LOS (6.2 vs. 3.5 days), greater ICU utilization (4.1 vs 2.0 days), and higher in-hospital mortality (0.52% vs. 0.01%, all p<.001).

Conclusions:
Though rare, cardiac complications during delivery in HDP patients are clinically significant and disproportionately affect those undergoing cesarean delivery and those with elevated geographic vulnerability. These findings underscore the need for targeted surveillance and equity-driven interventions in perinatal care.