Definitions of perioperative mortality rate
| Number of papers (%) | |
| Numerator | |
| Clearly defined | 455 (46.2) |
| Inpatient/hospital mortality (assumed for all studies lacking clear definition) | 703 (71.4) |
| Inpatient/hospital mortality, within 30 days of procedure | 13 (1.3) |
| 30-day mortality | 202 (20.5) |
| Mortality within 30 days or same hospitalisation | 32 (3.3) |
| 7-day mortality | 3 (0.3) |
| Intraoperative mortality | 14 (1.4) |
| 24 hours mortality | 4 (0.4) |
| Other | 14 (1.4) |
| Multiple | 24 (2.4) |
| Denominator | |
| Number of patients | 969 (98.4) |
| Number of procedures | 16 (1.6) |
Most studies did not explicitly state the timeframe during which deaths accrued. For those studies lacking clear time definitions, deaths were assumed to accrue during the index hospitalisation alone.