Details of trial feasibility estimates based on survey responses from Canadian vascular surgeons*
| Design | Centre | Willing surgeons; no. and area of expertise | Procedure; annual volume | Patients eligible for RCT; estimated no. annually | |||
|---|---|---|---|---|---|---|---|
| EVAR | Open repair | Both | EVAR | Open repair | |||
| Expertise-based RCT | A | 1 | 1 | 47 | 40 | 67 | |
| B | 2 | 1 | 95 | 30 | 110 | ||
| C | 1 | 1 | 14 | 40 | 34 | ||
| Total, all centres | 4 | 3 | 156 | 110 | 211 | ||
| Conventional RCT | A | 1 | 47 | 35 | 65 | ||
| B | 2 | 95 | 140 | 165 | |||
| C | 1 | 30 | 25 | 43 | |||
| D | 1 | 0 | 40 | 20 | |||
| E | 2 | 50 | 70 | 85 | |||
| F | 2 | 65 | 40 | 85 | |||
| G | 1 | 14 | 26 | 27 | |||
| Total, all centres | 10 | 301 | 376 | 489 | |||
EVAR = endovascular aneurysm repair; RCT = randomized controlled trial.
↵* To be included in the estimate for expertise-based design, a centre must contain at least 1 willing surgeon who fits the definition of endovascular expertise and 1 other willing surgeon who fits the definition of expertise in open repair. (26), (27) To be included in the estimate for conventional RCT design, a centre required only 1 willing surgeon, provided his or her level of expertise met the prespecified criteria for both open and endovascular repair.