PURPOSE: Patients currently presenting for coronary artery bypass grafting (CABG) surgery possess increased challenges due to higher complexity and more comorbid conditions. The objective of this study was to quantify this change in risk profile over a decade and to determine the potential implication on outcomes and operative mortality.
METHODS: Data was collected on 578,409 patients by querying the Healthcare Cost and Utilization Projects Nationwide Inpatient Sample (HCUP-NIS) for CABG patients from 1998 to 2007. Chi-square analysis was used to quantify the change in operative risk of the ’critical preoperative state’ variable which is defined as life threatening arrhythmias, aborted sudden death, pre-operative renal failure, pre-operative CPR, inotropic or ventilatory support with or without intra-aortic balloon pump. In addition, Chi-square and t-test analyses were used to determine whether there were significant changes in pre-operative risk, hospital mortality, age and length of stay. Multivariate logistic regression was conducted to predict in-hospital mortality from critical pre-operative state with adjustment for other pre-operative risk factors.
RESULTS: Since 1998, the annual number of CABG’s has decreased from 64,630 to 40,073 in 2007. Demographic evaluation revealed no clinically meaningful changes in average age (65.6 +/- 10.7 in 1998 vs 65.1 +/- 10.8, p< 0.001) and overall length of stay (9.1 +/- 7.5 in 2001 vs. 9.33 +/- 7.39, p< 0.001). In 1998, 18.5% of CABG surgery had a critical pre-operative state versus 27.5% in 2007 (p< 0.001). Results from the logistic regression analysis indicated that critical preoperative state confers significant increases in mortality risk (OR=8.9, p< 0.001). Despite the increase in the clinical complexity of patients, the mortality rates have decreased. In 1998, overall in-hospital mortality was 2.85% and decreased to 1.84% in 2007 (p< 0.001).
CONCLUSION: Over the past decade, patient demographics have not changed for age and gender. However, despite significant increases in patient risk profiles, the length of stay remained the same and moreover, operative mortality has significantly decreased.
CLINICAL IMPLICATIONS: Improved technical and technological aspects of CABG surgery will continue to improve patient outcomes.
DISCLOSURE: Shalin Desai, No Financial Disclosure Information; No Product/Research Disclosure Information