Effect of successful bariatric surgery on maternal cardiovascular outcomes

Abstract Background Obesity is a common comorbidity and is prevalent in at least 20% of pregnant women. Its prevalence is increasing at an alarming rate and is associated with worse pregnancy outcomes. With increasing obesity, more females are considering bariatric surgery (BS) as a form of weight-loss. Purpose The purpose of the study is to evaluate the effect of successful bariatric surgery (sBS) on maternal cardiovascular outcomes. Methods Pregnant females were sampled from the National Inpatient Sample Database (2016-2018). Demographics and comorbidities were collected using ICD-10 and DRG codes. Pregnant patients were stratified into three groups – morbidly obese, overweight/obese, and sBS. Individuals with a history of BS and not currently morbidly obese or overweight/obese were included in the sBS group. The primary outcome was a composite and was defined as major adverse cardiovascular events (MACE; Table 1). Secondary outcomes included pre-eclampsia (preE), gestational diabetes (GDM), and length of hospital stay (LOS). Patients with concurrent history of BS and overweight/obese/morbidly obese were excluded. To address confounding factors, sBS patients were matched 1:1 with morbidly obese and overweight/obese patients by 15 variables (Table 1). Binary logistic regression analyses were performed to assess for association between sBS and cardiac outcomes. Results Out of 207,511 patients included, 5,517 were sBS, 132,483 were overweight/obese, and 69,511 were morbidly obese. Compared to the sBS group (0.1%), MACE was higher in morbidly obese (0.7%) and overweight/obese patients (0.3%). Additionally, morbidly obese patients had higher acute heart failure, peripartum cardiomyopathy, acute pulmonary edema, preE, GDM, and longer LOS than sBS patients. Overweight/obese had more preE and GDM than the sBS cohort (Table 1). After 1:1 matching, MACE was more prevalent in morbidly obese patients (OR:6.69 [1.99-22.52]; p=0.002) and overweight/obese patients (OR:6.5 [1.5-28.9; p=0.01) when compared to sBS group. Both morbidly obese and overweight/obese groups were associated with increased preE (OR:3.0 and 2.1 respectively), GDM (OR:3.2 and 2.3 respectively), LOS (Coefficient:3.4 and 3.3 respectively; Figure 1). Conclusion Despite longstanding effects of obesity, sBS patients had better cardiovascular outcomes, even after matching for pre-existing cardiac conditions. A reduction in weight leads to decreased circulatory volume and improved cardiac output, resulting in lower risk of acute pulmonary edema, peripartum cardiomyopathy, and acute heart failure. The decrease in systemic inflammation and endothelial dysfunction likely led to a reduction in preE. Although pregnancy after bariatric surgery requires multidisciplinary management due to specific nutritional needs, the significant reduction in MACE highlights the importance of considering it as an option if conventional weight loss measures fail.Table 1Figure 1