Risk of not being discharged home after isolated coronary artery bypass graft operations

The age and risk profile of patients undergoing isolated coronary artery bypass grafting (CABG) is increasing, which will likely increase the proportion of CABG patients discharged to nursing homes, rehabilitation, or long-term care. Because discharge disposition can be important to a patient's treatment goals, developing and using predictive tools will improve informed treatment decision making. We examined the utility of The Society of Thoracic Surgeons (STS) risk of mortality score in predicting discharge disposition after CABG.

From January 1, 2004 to October 31, 2011, 5,119 patients underwent isolated CABG at The Heart Hospital Baylor Plano or Baylor University Medical Center (Texas) and were discharged alive. The association between STS risk of mortality and discharge to nursing home, rehabilitation, or long-term care was assessed using multivariable logistic regression, adjusted for age, body surface area, marital status, site, and year of operation.

At discharge, 216 patients (4.21%) went to nursing homes, 153 (2.99%) to rehabilitation, and 115 (2.25%) to long-term care. The STS risk of mortality score was significantly positively associated with discharge status (p < 0.001). Patients with 1%, 2%, 3%, 4%, and 5% STS risk of mortality had 11.25%, 22.10%, 29.45%, 35.00%, and 38.50% probability, respectively, of not being discharged home. When the STS risk of mortality was 5%, the risk of not being discharged home was 47.9% for off-pump patients and 38.10% for on-pump patients.

STS risk score is strongly associated with CABG discharge status. Patients with a risk score exceeding 2 are at high risk (>22%) of not being discharged home. This risk should be discussed when treatment decisions are being made.