Impact of Hospital Transfers on Cardiac Surgery Outcomes: A Society of Thoracic Surgeons Adult Cardiac Surgery Database Analysis.

Abstract

Background: Transfers for cardiac surgery are not well studied. We sought to understand the risk profile of transferred patients and determine whether transfer rates vary by cardiac surgery and whether outcomes of transferred patients vary with type of referral hospital/surgery.

Methods: Patients undergoing cardiac surgery with operative risk models were identified from The Society of Thoracic Surgeons database between July 1, 2014, and December 31, 2022. Patients were stratified as no transfer, transferred from hospital with cardiac surgery, and transferred from hospital without cardiac surgery. Risk associated with transfer compared with no transfer was derived by using multivariable logistic regression for operative mortality and select perioperative outcomes.

Results: Included were 1,828,787 patients at 1145 hospitals, with 1,452,491 no-transfer patients (79.4%), 28,862 transfers (1.6%) from hospitals with cardiac surgery, and 347,434 transfers (19.0%) from hospitals without cardiac surgery. Most transferred patients underwent coronary artery bypass grafting (83.6%); however, transfers from hospitals with cardiac surgery were most common for mitral valve replacement (17.9%). Transferred patients had increased comorbid diseases and urgent/emergent procedures. In multivariable analysis, transfers from hospitals with/without cardiac surgery were not associated with differential risk of adverse outcomes by procedure type. Patients transferred from hospitals with cardiac surgery undergoing mitral and aortic valve replacement and coronary artery bypass grafting had significantly lower adjusted mortality risk compared with nontransferred patients, whereas composite morbidity/mortality was higher in mitral valve repair.

Conclusions: Patients transferred for cardiac surgery are generally higher risk; yet, outcomes at transfer to hospitals are as expected or better. However, further research is necessary to examine patients who are transferred but do not undergo surgery.