Table 1.
Patient and Site Characteristics Grouped by Center-Level Average Predicted Risk of Mortality
| Center Risk Group |
|||||
|---|---|---|---|---|---|
| Variable | Q1 (Lowest) | Q2 | Q3 | Q4 | Q5 (Highest) |
| N (centers) | 200 | 201 | 200 | 201 | 200 |
| N (patients) | 95,150 | 113,396 | 105,274 | 100,652 | 80,483 |
| Annual CABG volume per site (IQR) | 352 (195, 565) | 444 (291, 680) | 438 (236, 715) | 415 (255, 640) | 307 (193, 488) |
| Age, years (IQR) | 64 (57, 71) | 65 (57, 72) | 65 (57, 73) | 66 (58, 73) | 66 (58, 74) |
| Age ≥75 years, % | 16.9 | 19.3 | 20.3 | 21.7 | 23.4 |
| Female, % | 26.1 | 26.5 | 26.9 | 26.9 | 27.7 |
| Race, % | |||||
| White | 88.8 | 88.1 | 87.5 | 85.3 | 81.3 |
| Black | 6.9 | 6.9 | 6.6 | 7.5 | 7.5 |
| Asian | 1.2 | 1.8 | 1.8 | 2.5 | 4.7 |
| Hispanic ethnicity, % | 3.1 | 3.9 | 5.0 | 7.3 | 8.5 |
| Creatinine >1.5 mg/dL, % | 7.3 | 8.3 | 9.1 | 9.3 | 10.9 |
| Comorbidities, % | |||||
| Diabetes | 38.7 | 39.4 | 40.5 | 41.0 | 43.6 |
| Hypertension | 83.9 | 84.4 | 85.4 | 85.6 | 87.1 |
| Chronic lung disease: moderate or severe | 7.1 | 8.0 | 9.9 | 11.0 | 15.7 |
| Peripheral vascular disease | 12.3 | 13.6 | 15.4 | 16.0 | 18.1 |
| Cerebrovascular disease | 12.8 | 13.9 | 14.7 | 14.8 | 15.8 |
| Cerebrovascular accident | 5.7 | 6.4 | 7.1 | 7.0 | 7.6 |
| Renal failure; dialysis | 1.8 | 2.2 | 2.4 | 2.7 | 3.6 |
| Myocardial infarction | 43.0 | 44.7 | 47.8 | 49.4 | 51.7 |
| Intraaortic balloon pump | 7.0 | 9.0 | 10.3 | 10.9 | 13.4 |
| NYHA class IV | 19.5 | 22.5 | 25.8 | 26.3 | 31.7 |
| Congestive heart failure | 11.4 | 13.0 | 17.6 | 18.3 | 22.6 |
| Three-vessel disease, % | 73.5 | 74.3 | 74.5 | 75.8 | 77.0 |
| Left main disease >50%, % | 30.0 | 30.4 | 31.7 | 33.0 | 33.5 |
| Procedure status, % | |||||
| Urgent | 46.3 | 53.1 | 53.9 | 56.0 | 60.1 |
| Emergent | 2.7 | 3.9 | 4.4 | 5.5 | 6.9 |
| Predicted risk of mortality, % | 1.46 | 1.75 | 1.97 | 2.23 | 2.87 |
CABG = coronary artery bypass grafting; IQR = interquartile range; NYHA = New York Heart Association.