Table 1.
Characteristics of study participants.
| Variable | No SSI, n = 1238 | SSI, n = 60 | p |
|---|---|---|---|
| Preoperative factors | |||
| Age in years (mean ± SD) | 68 ± 12 | 72 ± 10 | 0.042 |
| Males (n, %) | 706 (57) | 29 (48) | 0.186 |
| Diabetes (n, %) | 314 (25) | 32 (53) | <0.001 |
| Obesity or BMI >30 kg/m2 (n, %) | 54 (4) | 11 (18) | <0.001 |
| Peripheral artery disease (n, %) | 85 (7) | 9 (15) | 0.025 |
| Chronic kidney disease (n, %) | 107 (9) | 4 (7) | 0.405 |
| Intraoperative factors | |||
| Emergency surgery (n, %) | 84 (7) | 4 (7) | 0.786 |
| Type of surgery (n, %): | 0.099 | ||
| CARD | 907 (73) | 37 (62) | |
| CABG | 205 (17) | 16 (27) | |
| CARD + CABG | 126 (10) | 7 (12) | |
| Duration of surgery in min (mean ± SD) | 281 ± 81 | 303 ± 75 | 0.034 |
| Aortic clamping time in min (mean ± SD) | 67 ± 37 | 74 ± 39 | 0.191 |
| Total CPB in min (mean ± SD) | 96 ± 50 | 102 ± 58 | 0.426 |
| Appropriate prophylaxis (n, %) | 269 (22) | 12 (22) | 0.552 |
| Risk score | |||
| 75P duration of surgery or 300 min (n, %) | 402 (33) | 29 (48) | 0.009 |
| Clean surgery (n, %) | 1129 (91) | 56 (93) | 0.845 |
| ASA score ≥ III (n, %) | 1088 (88) | 56 (93) | 0.145 |
| NNIS risk index (n, %): | 0.011 | ||
| 0 | 93 (8) | 2 (3) | |
| 1 | 742 (60) | 28 (47) | |
| 2 | 377 (31) | 30 (50) | |
| 3 | 26 (2) | 0 (0) | |
| Postoperative factors | |||
| Reoperation for bleeding (n, %) | 51 (4) | 8 (13) | 0.004 |
| Length of hospital stay in days (mean ± SD): | |||
| Before surgery | 6 ± 6 | 5 ± 4 | 0.152 |
| After surgery | 16 ± 15 | 17 ± 14 | 0.501 |
| Total in-hospital stay | 21 ± 17 | 22 ± 15 | 0.925 |
| Hospital mortality | 72 (6) | 6 (10) | 0.133 |
ASA, American Society of Anesthesiologists; BMI, body mass index; CABG, coronary artery bypass graft; CARD, cardiac valve surgery; CPB, cardiopulmonary bypass; NNIS, National Nosocomial Infections Surveillance; P75, 75th percentile; SSI, surgical site infection.