Table 1.
Characteristics of 20 988 participants stratified by anaesthetic technique used for lower limb revascularisation surgery. Values are numbers (percentages) unless stated otherwise
| Characteristics | Neuraxial anaesthesia (n=6453) | General anaesthesia (n=14 535) | Absolute standardised difference* |
|---|---|---|---|
| Personal characteristics | |||
| Mean (SD) age (years) | 70.6 (10.7) | 67.6 (12.7) | 0.25 |
| Women | 2132 (33.0) | 4763 (32.8) | 0 |
| Rural residence | 1071 (16.6) | 2639 (16.3) | 0 |
| Long term care facility resident | 159 (2.5) | 233 (1.6) | 0.06 |
| Income fifth: | |||
| 1 (lowest) | 1569 (24.3) | 3554 (24.5) | 0 |
| 2 | 1419 (22.0) | 3167 (21.8) | 0 |
| 3 | 1231 (19.1) | 2758 (19.0) | 0 |
| 4 | 1173 (18.2) | 2618 (18.0) | 0.01 |
| 5 (highest) | 1061 (16.4) | 2438 (16.8) | 0.01 |
| Smoking cessation consultation in year before surgery | 168 (2.6) | 375 (2.6) | 0 |
| Mean (SD) HOMR score† | 31.7 (6.0) | 31.0 (6.5) | 0.11 |
| Comorbidities recorded in 3 years before surgery | |||
| Alcohol misuse | 176 (2.7) | 417 (2.9) | 0.01 |
| Atrial fibrillation | 569 (8.8) | 1228 (8.5) | 0.01 |
| Blood loss anaemia | 755 (11.7) | 1647 (11.3) | 0.01 |
| Cancer | 382 (5.9) | 865 (6.0) | 0 |
| Cardiac valvular disease | 219 (3.4) | 908 (6.3) | 0.14 |
| Cerebrovascular disease | 432 (6.7) | 881 (6.1) | 0.02 |
| Chronic kidney disease | 587 (9.1) | 997 (6.9) | 0.08 |
| Chronic obstructive pulmonary disease | 2639 (40.9) | 5260 (36.2) | 0.10 |
| Coagulopathy | 190 (2.9) | 656 (4.5) | 0.08 |
| Deficiency anaemia | 65 (1.0) | 121 (0.8) | 0.02 |
| Dementia | 126 (2.0) | 219 (1.5) | 0.04 |
| Depression | 182 (2.8) | 427 (2.9) | 0.01 |
| Diabetes | 3162 (49.0) | 6301 (43.4) | 0.11 |
| Dialysis | 322 (5.0) | 558 (3.8) | 0.06 |
| Drug misuse | 30 (0.5) | 63 (0.4) | 0.01 |
| Frailty | 1383 (21.4) | 2710 (18.6) | 0.07 |
| Heart failure | 1588 (24.6) | 3047 (21.0) | 0.09 |
| Hemiparesis or hemiplegia | 59 (0.9) | 106 (0.7) | 0.02 |
| Hypertension | 5199 (81.0) | 11 306 (77.8) | 0.08 |
| Liver disease | 78 (1.2) | 164 (1.1) | 0.01 |
| Metastatic cancer | 45 (0.7) | 146 (1.0) | 0.03 |
| Myocardial infarction | 871 (13.5) | 1919 (13.2) | 0 |
| Obesity | 134 (2.1) | 350 (2.4) | 0.02 |
| Peptic ulcer disease | 134 (2.1) | 243 (1.7) | 0.03 |
| Previous diagnosis of peripheral artery disease | 2579 (40.0) | 4786 (32.9) | 0.15 |
| Psychosis | 23 (0.4) | 75 (0.5) | 0.01 |
| Pulmonary circulatory disease | 96 (1.5) | 295 (2.0) | 0.04 |
| Rheumatic disease | 69 (1.1) | 153 (1.1) | 0 |
| Venous thromboembolism | 78 (1.2) | 185 (1.3) | 0.01 |
| Weight loss | 113 (1.8) | 219 (1.5) | 0.02 |
| Healthcare resource use | |||
| Emergency department visit in past year | 4072 (63.1) | 9001 (61.9) | 0.02 |
| Hospital admission in past year | 2594 (40.2) | 5919 (40.7) | 0.01 |
| Resource utilisation band: | |||
| 1 – healthy user | ‡ | ‡ | N/A |
| 2 – low morbidity | ‡ | ‡ | N/A |
| 3 – moderate | 827 (12.8) | 1658 (11.4) | 0.04 |
| 4 – high | 1509 (23.4) | 3453 (23.8) | 0.01 |
| 5 – very high | 4113 (63.7) | 9373 (64.5) | 0.02 |
| Lower limb revascularisation surgery | |||
| Mean (SD) hospital volume of lower limb revascularisation yearly | 1450 (784) | 1480 (842) | 0.04 |
| Urgency: | |||
| Elective | 4112 (63.7) | 8492 (58.4) | 0.11 |
| Urgent | 1847 (28.6) | 3922 (27.0) | 0.04 |
| Emergent | 109 (1.7) | 326 (2.2) | 0.04 |
| Critical | 385 (6.0) | 1795 (12.4) | 0.22 |
| Procedure: | |||
| Infrainguinal bypass | 5583 (86.5) | 10 917 (75.1) | 0.29 |
| Using autogenous graft material | 3393 (52.6) | 6368 (43.8) | 0.18 |
| Using synthetic graft material | 2044 (31.7) | 4171 (28.7) | 0.07 |
| Using composite graft material | 146 (2.3) | 378 (2.6) | 0.02 |
| Repair of arteries below inguinal ligament | 653 (10.1) | 3158 (21.7) | 0.32 |
| Using autograft material | 159 (2.5) | 665 (4.6) | 0.11 |
| Using synthetic material | 288 (4.5) | 871 (6.0) | 0.07 |
| Without using above materials | 206 (3.2) | 1622 (11.2) | 0.31 |
HOMR=Hospital-patient One-year Mortality Risk; NA=not applicable.
*
Difference in prevalence of binary covariates, or average of continuous covariates, between treatment groups without influence of sample size; values greater than 0.1 indicate substantive differences.
†
Range from −12 to 76, with higher scores denoting greater risk of death.
‡
Privacy legislation does not allow reporting of cell sizes of 6 or less, or cells that allow calculation of a cell of 6 or less.