Table 2.
Characteristics of patients by centre in the complete case data
| Bristol (n = 12,435) | Birmingham (n = 4,092) | Wolverhampton (n = 4,468) | |
|---|---|---|---|
| Number (%) | Number (%) | Number (%) | |
| Demographic factors | |||
| Age, years | |||
| <60 | 2,995 (24.1) | 1,061 (25.9) | 1,026 (23.0) |
| 60 to 74 | 6,873 (55.3) | 2,201 (53.8) | 2,471 (55.3) |
| ≥75 | 2,567 (20.6) | 830 (20.3) | 971 (21.7) |
| Sex | |||
| Male | 9,474 (76.2) | 2,990 (73.1) | 3,420 (76.5) |
| Female | 2,961 (23.8) | 1,102 (26.9) | 1,048 (23.5) |
| Body mass index | |||
| <20.0 | 482 (3.9) | 112 (2.7) | 87 (1.9) |
| 20.0 to 24.9 | 3,206 (25.8) | 1,003 (24.5) | 1,057 (23.7) |
| 25.0 to 29.9 | 5,685 (45.7) | 1,737 (42.4) | 2,020 (45.2) |
| 30.0 to 34.9 | 2,365 (19.0) | 893 (21.8) | 967 (21.6) |
| 35.0+ | 697 (5.6) | 347 (8.5) | 337 (7.5) |
| Smoking status | |||
| Never smoked | 3,970 (31.9) | 1,351 (33.0) | 1,633 (36.5) |
| Ex-smoker | 7,072 (56.9) | 2,427 (59.3) | 2,414 (54.0) |
| Current smoker | 1,393 (11.2) | 314 (7.7) | 421 (9.4) |
| Preoperative factors | |||
| Anginaa | |||
| No angina | 2,346 (18.9) | 737 (18.0) | 779 (17.4) |
| CCS 1 | 1,460 (11.7) | 399 (9.8) | 244 (5.5) |
| CCS 2 | 3,611 (29.0) | 1,354 (33.1) | 1,342 (30.0) |
| CCS 3 | 2,885 (23.2) | 949 (23.2) | 1,142 (25.6) |
| CCS 4 | 2,133 (17.2) | 653 (16.0) | 961 (21.5) |
| Dyspnoeab | |||
| NYHA 1 | 2,797 (22.5) | 786 (19.2) | 926 (20.7) |
| NHYA 2 | 5,129 (41.2) | 2,094 (51.2) | 1,748 (39.1) |
| NYHA 3 | 3,895 (31.3) | 928 (22.7) | 1,353 (30.3) |
| NYHA 4 | 614 (4.9) | 284 (6.9) | 441 (9.9) |
| Previous MI | |||
| 0 | 7,786 (62.6) | 2,671 (65.3) | 2,453 (54.9) |
| 1 | 3,783 (30.4) | 1,145 (28.0) | 1,620 (36.3) |
| ≥2 | 866 (7.0) | 276 (6.7) | 395 (8.8) |
| Previous operations | |||
| 0 | 1,1940 (96.0) | 3,895 (95.2) | 4,352 (97.4) |
| 1+ | 495 (4.0) | 197 (4.8) | 116 (2.6) |
| Preoperative diabetes | |||
| No | 10,243 (82.4) | 3,176 (77.6) | 3,399 (76.1) |
| Yes | 2,192 (17.6) | 916 (22.4) | 1,069 (23.9) |
| Peripheral vascular disease | |||
| No | 11,388 (91.6) | 3,536 (86.4) | 3,665 (82.0) |
| Yes | 1,047 (8.4) | 556 (13.6) | 803 (18.0) |
| Pulmonary disease | |||
| No | 10,991 (88.4) | 3,499 (85.5) | 3,926 (87.9) |
| Yes | 1,444 (11.6) | 593 (14.5) | 542 (12.1) |
| Neurological disease | |||
| No | 11,303 (90.9) | 3,790 (92.6) | 4,077 (91.2) |
| Yes | 1,132 (9.1) | 302 (7.4) | 391 (8.8) |
| Hypertensionc | |||
| No | 4,400 (35.4) | 1,307 (31.9) | 1,673 (37.4) |
| Yes | 8,035 (64.6) | 2,785 (68.1) | 2,795 (62.6) |
| Haemoglobin | |||
| <10.0 | 218 (1.8) | 91 (2.2) | 71 (1.6) |
| 10.0 to11.9 | 1,487 (12.0) | 593 (14.5) | 515 (11.5) |
| 12.0+ | 10,730 (86.3) | 3,408 (83.3) | 3,882 (86.9) |
| GFR | |||
| <30.0 | 436 (3.5) | 102 (2.5) | 54 (1.2) |
| 30.0 to 59.9 | 4,592 (36.9) | 1,460 (35.7) | 1,059 (23.7) |
| 60.0 to 89.9 | 5,458 (43.9) | 1,741 (42.5) | 1,887 (42.2) |
| 90.0+ | 1,949 (15.7) | 789 (19.3) | 1,468 (32.9) |
| Heparin or nitrates | |||
| None | 10,724 (86.2) | 3,595 (87.9) | 4,133 (92.5) |
| Within a week | 914 (7.4) | 53 (1.3) | 114 (2.6) |
| At operation | 797 (6.4) | 444 (10.9) | 221 (4.9) |
| Critical preoperative event | |||
| No | 12,268 (98.7) | 3,944 (96.4) | 4,392 (98.3) |
| Yes | 167 (1.3) | 148 (3.6) | 76 (1.7) |
| Catheter to surgery | |||
| Within 24 h | 299 (2.4) | 38 (0.9) | 84 (1.9) |
| >24 h this admission | 6,825 (54.9) | 1,019 (24.9) | 971 (21.7) |
| >24 h previous admission | 5,311 (42.7) | 3,035 (74.2) | 3,413 (76.4) |
| Triple vessel disease | |||
| No | 6,041 (48.6) | 1,759 (43.0) | 1,819 (40.7) |
| Yes | 6,394 (51.4) | 2,333 (57.0) | 2,649 (59.3) |
| Left main stem disease | |||
| No | 10,208 (82.1) | 3,162 (77.3) | 3,422 (76.6) |
| Yes | 2,227 (17.9) | 930 (22.7) | 1,046 (23.4) |
| Ejection fraction | |||
| Good (50+ %) | 9,111 (73.3) | 2,758 (67.4) | 2,910 (65.1) |
| Fair (30 to 49%) | 2,668 (21.5) | 1,143 (27.9) | 1,192 (26.7) |
| Poor (<30%) | 656 (5.3) | 191 (4.7) | 366 (8.2) |
| Operative priority | |||
| Elective | 7,350 (59.1) | 2,798 (68.4) | 3,173 (71.0) |
| Urgent | 4,896 (39.4) | 1,256 (30.7) | 1,255 (28.1) |
| Emergency/salvage | 189 (1.5) | 38 (0.9) | 40 (0.9) |
| Cardiac procedures | |||
| CABG only | 8,587 (69.1) | 2,241 (54.8) | 2,974 (66.6) |
| Valve only | 1,838 (14.8) | 644 (15.7) | 622 (13.9) |
| CABG+valve | 1,169 (9.4) | 554 (13.5) | 568 (12.7) |
| Other/multiple | 841 (6.8) | 653 (16.0) | 304 (6.8) |
| Acute kidney injury, % | |||
| None | 9,495 (76.4) | 3,238 (79.1) | 3,370 (75.4) |
| Stage 1 | 2,164 (17.4) | 560 (13.7) | 706 (15.8) |
| Stage 2 | 330 (2.7) | 89 (2.2) | 124 (2.8) |
| Stage 3 | 446 (3.6) | 205 (5.0) | 268 (6.0) |
aCanadian Cardiovascular Society (CCS) classes: 1 ordinary activity does not cause angina; 2 slight limitation; 3 marked limitation; 4 inability to carry out any physical activity without discomfort. bNew York Heart Association (NYHA) functional classification: 1 no symptoms and no limitation in ordinary physical activity; 2 mild symptoms and slight limitation during ordinary activity; 3 marked limitation in activity due to symptoms, comfortable only at rest; 4 severe limitations, experiences symptoms even while at rest. cHypertension was defined as treated or blood pressure >140/90. CABG, coronary artery bypass graft; GFR, glomerular filtration rate; Haemoglobin, g/dL; GFR, mL/min.