Impact of transfer status on coronary artery bypass graft surgery outcomes
Authors: Gill A , Al-Taweel O , Schreiber A , Hawwass D , Ahsan C 
Published: October 2022

Abstract

Background
There is limited research on how patients fare when they are transferred from one acute care center to another acute care facility for further management.

Purpose
In this study, we explore the short-term, in-hospital outcomes of patients undergoing coronary artery bypass graft (CABG) surgery who were transferred to acute care hospitals from other acute care centers.

Methods
This was a retrospective cohort study comparing adult patients who were transferred to the hospital from other acute centers with non-transferred hospital admissions between 2016 to 2018. We queried the National Inpatient Sample database to identify patients admitted with a principal procedural diagnosis of CABG. We analyzed the categorical and continuous variables by Pearson's chi-squared and Student t-test respectively. Multivariable logistic regression, adjusted for age, gender, hospital bed size, hospital location and comorbidities, was used to compare mortality. The comorbidities adjusted for included atrial fibrillation, chronic kidney disease, heart failure, hypertension, obesity and type 2 diabetes mellitus.

Results
379,195 patients met our inclusion criteria. CABG patients transferred from acute care centers had 1.34 times higher odds of suffering in-hospital mortality compared to regular hospital admissions (aOR 1.34, 95% CI: 1.17–1.52; p&lt;0.001). When separated by race, acute care transfers had higher mortality rates amongst White patients (2.2% vs 1.4%, p&lt;0.001, Figure 1) as well as longer hospital stays (10.9 vs 8.8 days, p&lt;0.001, Table 1). Acute care transfers consisted of more female patients, had higher average APR-DRG mortality scores and lower median household income (Table 1). These patients also had higher rates of comorbidities such as congestive heart failure and chronic kidney disease, but decreased rates of atrial fibrillation, hypertension, obesity, prior myocardial infarction and type 2 diabetes mellitus (Table 1). In terms of operative complications, acute care transfers were more likely to have intraoperative cardiac arrest (0.2% vs 0.1%, p&lt;0.001) and postoperative cardiac insufficiency (0.2% vs 0.1%, p&lt;0.001, Table 1). There was no significant difference between our two cohorts in postoperative complications such as cardiac arrest, intracerebral infarction or heart failure.

Conclusion
Patients who were transferred to acute care hospitals from other acute care centers to undergo CABG had higher odds of suffering in-hospital mortality compared to regular hospital admissions. These patients were also at increased risk of intraoperative cardiac arrest and postoperative cardiac insufficiency. Our findings illustrate that acute care transfers undergoing CABG require additional medical support in the operative and postoperative setting. While additional studies are required to better understand this relationship, this study highlights the need for innovative clinical change to address these differences moving forward.

Funding Acknowledgement
Type of funding sources: None.