SCAMICOS 2010.

Methods	Site: BK popliteal and distal (the latter not included in this review) Study design: multicentre RCT Method of randomisation: concealed randomisation using sealed envelopes in blocks of 16 per centre Blinding: unblinded, intention to treat Exclusions post randomisation: 3 (1%) Losses to follow up: 0 (0%) Protocol violations: 3 (1 ‐ suitable vein available, 1 ‐ distal reconstruction below popliteal artery, 1 ‐ crossover from non‐collar to collar group)
Participants	Country: 29 centres in Sweden and 3 in Denmark Setting: hospital No. of participants: 202 (87 PTFE, 115 PTFE with vein collar) Age (median): 79 yrs in PTFE group, 76 yrs in PTFE with collar group Gender: 77 males, 122 females; 3 excluded Inclusion criteria: rest pain, tissue loss Exclusion criteria: no suitable distal anastomotic target, distal anastomosis AK or below anterior tibial origin for BK popliteal group, or below‐ankle for distal group
Interventions	Gore or Impra PTFE graft with or without distal vein cuff, diameter not specified (diameter at discretion of operating surgeon)
Outcomes	Primary patency; secondary patency; amputation; death
Notes	No consistent anticoagulation protocol
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No description of randomisation sequence generation technique
Allocation concealment (selection bias)	Low risk	Envelope selected at random after confirmation of suitable target vessel
Blinding of participants and personnel (performance bias) All outcomes	High risk	Operative blinding impossible in this type of trial
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Outcome assessors and patients not obviously blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only 3 patients had missing follow‐up data
Selective reporting (reporting bias)	Low risk	All stated outcomes reported
Other bias	Unclear risk	No consistent anticoagulation protocol