Risk factors, resource use, and cost of postoperative low cardiac output syndrome

Abstract

Objective: Low cardiac output syndrome complicates recovery after cardiac surgery. We examined the incidence and risk factors for low cardiac output syndrome and its association with postoperative mortality, morbidity, resource use, and cost.

Methods: This cross-sectional retrospective observational study examined patients having cardiac surgery captured in the Premier Healthcare Database. Low cardiac output syndrome was defined as the requirement for postoperative mechanical circulatory support and/or hemodynamic instability requiring prolonged inotropic support. Incidence, risk factors, and association of low cardiac output syndrome with postoperative outcomes, including mortality, hospital and intensive care unit length of stay, hospital readmission, and cost at 30 days, 90 days, and 6 months, were examined.

Results: Among 59,810 patients from 164 hospitals having cardiac surgery between July 1, 2012, and June 30, 2014, low cardiac output syndrome developed in 6067 (10.1%) patients. Patients presenting in cardiogenic shock or systolic (± diastolic) heart failure were at greatest risk. Risk-adjusted in-hospital mortality was 12-fold greater with low cardiac output syndrome (odds ratio, 12.0; 95% confidence interval, 10.6-13.5). Risk-adjusted hospital costs (2019$; median [Q1, Q3]) were $64,041 [21,439] in patients who developed low cardiac output syndrome versus $48,086 [16,098] without; P < .001. Increased costs were driven by longer risk-adjusted hospital stay (10.1 [4.5] vs 8.5 [3.8] days); P < .001, intensive care unit (5.5 [2.5] vs 3.3 [1.5] days; P < .001) stay, and all-cause 30-day adjusted hospital readmission rates (mean [SD] 16.6 [8.2]% vs 13.9 [7.2]%; P < .001).

Conclusions: Cardiac surgical patients who develop postoperative low cardiac output syndrome suffer greater mortality and have greater resource use, health care costs, and all-cause readmission, which informs perioperative decision making, and impacts hospital performance metrics and federal priority to reduce health care costs.

Keywords: cardiac surgery; cost; hospital readmission; postoperative complications.