The Impact of Antimicrobial Resistance on Outcomes for Patients Undergoing Coronary Artery Bypass Graft and Valve Surgery: A Retrospective Cohort Study of Hospital Admissions Data from the National Inpatient Sample

Background: There is uncertainty regarding the impact of multidrug-resistant organisms on patients that undergo cardiac surgery. Methods: A retrospective cohort study was performed by using 2016–2019 data from the National Inpatient Sample in the United States to evaluate the proportion of admissions with a diagnosis of antimicrobial resistance who also underwent coronary artery bypass graft or valve surgery. Results: A total of 1,260,630 admissions were included in the analysis, of which 2045 (0.16%) had antimicrobial resistance. Compared to patients without resistance, those with antimicrobial resistance were more likely to be female (52.8% vs. 31.5%, p < 0.001), and die in a hospital (7.1% vs. 2.4%, p < 0.001). The length of stay and cost were significantly higher for patients with antimicrobial resistance (15 vs. 7 days and USD 69,135 vs. USD 43,740, respectively). Antimicrobial resistance was not associated with increased in-hospital mortality (OR 1.38; 95% CI 0.86–2.21, p = 0.18), although it was associated with an increase in length of stay (coefficient 7.65; 95% CI 6.91–8.39, p < 0.001), and cost (coefficient USD 25,240 [21,626–28,854], p < 0.001). Conclusions: Antimicrobial resistance in patients that undergo cardiac surgery is not common, yet its burden is substantial as it can double the length of stay and increase costs by more than USD 20,000.