Stonebridge 1997.

Methods	Site: Femoral to AK or BK popliteal Study design: multicentre RCT Method of randomisation: central randomisation centre assessment of artery and vein Blinding: unblinded, intention to treat Exclusions post randomisation: not specified Losses to follow up: not stated Protocol violations: none declared
Participants	Country: UK Setting: multicentre No. of participants: 246 Inclusion criteria: femoro‐popliteal graft to AK (76 cuff, 74 no cuff) or BK (48 cuff, 47 no cuff) popliteal Exclusion criteria: trauma
Interventions	6 mm PTFE with and without a vein cuff
Outcomes	Primary patency, secondary patency, limb salvage
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 technique
Allocation concealment (selection bias)	Unclear risk	No clear description
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	Unclear risk	Attrition rates not clearly presented
Selective reporting (reporting bias)	Low risk	All stated outcomes reported
Other bias	Unclear risk	No consistent anticoagulation protocol