Body mass index is associated with low postoperative cardiac output in patients undergoing aortic valve replacement

Overweight and obesity (O/O) generate lipotoxicity of the cardiac fiber and increase the incidence and progression of aortic valve stenosis. The low cardiac output syndrome (LCOS) is a timing complication after to aortic valve replacement (AVR) surgery.

The objective of the study was to investigate if body mass index (BMI) kg/m² is a risk factor associated with LCOS and mortality in the post-operative period of AVR.

A historic cohort study was designed, including patients with severe aortic stenosis (SAS), who were subjected to AVR.

152 patients were included, 45 (29.6%), with normal weight (NW), 60 were overweight (39.5%), and 47 obese (30.9%). The prevalence of systemic hypertension (HT) was higher in O/O (p < 0.0001). Incidence of LCOS was 44.7%, being more frequent in the O/O groups compared to the NW group, 43.3%, 68.1%, and 22.2%, respectively, (p < 0.05 in overweight and p < 0.0001 in the obese). Assessing the presence or absence of LCOS associated with BMI as a numerical variable, we found that women, HT, BMI, left ventricular mass, and valve size, were associated with LCOS (p < 0.02, p < 0.02, p < 0.001, p < 0.032, and p < 0.045, respectively). Mortality was higher in patients who had LCOS (p < 0.02). Multivariate model showed that BMI was an independent risk factor for LCOS (odds ratio [OR] 1.21 [95% CI 1.08-1.35], p < 0.001).

BMI is a risk factor associated to LCOS in the post-operative period of AVR in patients with SAS.