Table 2. Patient characteristics by volume group classification (16,612 total procedures).
| Characteristic | Low-volume (1–5 events), N (%) | Moderate-volume (6–11 events), N (%) | High-volume (>11 events), N (%) | P values |
|---|---|---|---|---|
| Procedures (N=16,612) | 1,879 | 10,497 | 4,236 | |
| Age (mean ± SD) | 63.2±12.2 | 63.5±12.3 | 63.4±12.1 | 0.47 |
| Female | 734 (39.1) | 3,997 (38.1) | 1,563 (36.9) | 0.21 |
| Charlson (mean ± SD) | 2.3±2.2 | 2.1±2.2 | 2.1±2.1 | <0.01 |
| MI | 649 (34.5) | 3,094 (29.5) | 1,241 (29.3) | <0.01 |
| CHF | 573 (30.5) | 2,880 (27.4) | 1,091 (25.8) | <0.01 |
| PVD | 244 (13.0) | 1,028 (9.8) | 510 (12.0) | <0.01 |
| Stroke | 274 (14.6) | 1,287 (12.3) | 608 (14.4) | <0.01 |
| DM | 791 (42.1) | 3,994 (38.0) | 1,600(37.8 | <0.01 |
MI, myocardial infarction; Charlson, Charlson Comorbidity Index; CHF, congestive heart failure; PVD, peripheral vascular disease; DM, diabetes; SD, standard deviation.