Declining in-hospital mortality in patients undergoing coronary bypass surgery in the United States irrespective of presence of type 2 diabetes or congestive heart failure

Abstract

Background: Significant advances in surgical techniques and postsurgical care have been made in the last 10 years. The goal of this study was to evaluate any decline in the age-adjusted in-hospital mortality rate of patients undergoing coronary artery bypass grafting (CABG) using a national database from 1989 to 2004 in the United States.

Hypothesis: Reduction in CABG related mortality in recent years.

Methods: Using the Nationwide Inpatient Sample (NIS) database, we obtained specific ICD-9-CM codes forCABG to compile the data. To exclude nonatherosclerotic cause of coronary disease, we studied only patients older than 40 years. We calculated total and age-adjusted mortality rate per 100,000 for this period.

Results: The NIS database contained 1 145 285 patients who had CABG performed from 1988 to 2004. The mean age for these patients was 71.05 ± 9.20 years. From 1989, the age-adjusted rate for all CABG-related mortality has been decreasing steadily and reached the lowest level in 2004: 300.3 per 100 000 in 1989, (95%confidence interval [CI], 20.4-575.9) and 104.69 per 100 000 (95% CI, 22.6-186.7) in 2004. Total death also declined from 5.5% to 3.06%. This decline occurred irrespective of comorbidities such as congestive heart failure, diabetes, or acute myocardial infarction, albeit increasing the number of CABG procedures performed in high-risk patients.

Conclusions: The age-adjusted in-hospital mortality rate from CABG has been declining steadily and reached its lowest level in 2004, irrespective of comorbidities. This decline most likely reflects advances in surgical techniques and the use of evidence-based medicine in patients undergoing CABG.

Figure 1

Steady decline in the age‐adjusted coronary artery bypass grafting (CABG)‐related in‐hospital mortality in recent years.

Figure 2

Steady decline in the coronary artery bypass grafting (CABG)‐related total mortality in recent years.

Figure 3

Steady decline in the age‐adjusted coronary artery bypass grafting (CABG)‐related mortality irrespective of comorbidities. DM, type 2 diabetes; CHF, congestive heart failure; STEMI, ST‐elevation myocardial infarction; Non STEMI, non–ST‐elevation myocardial infarction.

Figure 4

Gradual increase in the age‐adjusted rate of coronary artery bypass grafting (CABG) performed in high‐risk patients in recent years, except in patients with ST‐elevation myocardial infarction (STEMI). DM, type 2 diabetes; CHF, congestive heart failure; Non STEMI, non–ST‐elevation myocardial infarction.