Clinical characteristics and in-hospital outcomes of patients with cardiogenic shock undergoing coronary artery bypass surgery: insights from the Society of Thoracic Surgeons National Cardiac Database.

BACKGROUND: There exist few studies that characterize contemporary clinical features and outcomes or risk factors for operative mortality in cardiogenic shock (CS) patients undergoing coronary artery bypass grafting (CABG). METHODS AND
RESULTS: We evaluated data of 708,593 patients with and without CS undergoing CABG enrolled in the Society of Thoracic Surgeons National Cardiac Database (2002-2005). Clinical, angiographic, and operative features and in-hospital outcomes were evaluated in patients with and without CS. Logistic regression was used to identify predictors of operative mortality and to estimate weights for an additive risk score. Patients with preoperative CS constituted 14,956 (2.1%) of patients undergoing CABG yet accounted for 14% of all CABG deaths. Operative mortality in CS patients was high and surgery specific, rising from 20% for isolated CABG to 33% for CABG plus valve surgery and 58% for CABG plus ventricular septal repair. Although mortality for CABG surgery overall declined significantly over time (P for trend <0.0001), mortality for CS patients undergoing CABG did not change significantly during the 4-year study period (P=0.07). Factors associated with higher death risk for CS patients undergoing CABG were identified by multivariable analysis and summarized into a simple bedside risk score (c statistic=0.74) that accurately stratified those with low (<10%) to very high (>60%) mortality risk.
CONCLUSIONS: Patients with CS represent a minority of those undergoing CABG yet have persistently high operative risks, accounting for 14% of deaths in CABG patients. Estimation of patient-specific risk of mortality is feasible with the simplified additive risk tool developed in our study with the use of routinely available preprocedural data.