Ballotta 2003.

Methods	Site: Femoral to AK popliteal Study design: RCT Method of randomisation: concealed randomisation using computer generated randomisation envelopes Blinding: unblinded, intention to treat Exclusions post randomisation: none Losses to follow up: none
Participants	Country: Italy Setting: hospital No. of participants: 51 (102 limbs; 51 PTFE, 51 reversed vein) Age (mean): 62 yrs Sex: 33 males, 18 females Inclusion criteria: severe claudication, SFA occlusion with one to three runoff vessels Exclusion criteria: untreated inflow disease of ipsilateral pelvic arteries (more than 50% stenosis or occlusion); previous bypass procedure or stent in target SFA; multiple lesions exceeding 10 cm; acute critical limb ischaemia; an untreated ipsilateral iliac artery stenosis; known intolerance to study medications or contrast agents
Interventions	8 mm PTFE and reversed vein graft Oral warfarin from one day pre‐op and continued for 6 months; 325 mg aspirin afterwards
Outcomes	Primary assisted patency as remedial surgery for late bypass stenosis was not considered a primary failure 5‐year data
Notes	Compliance with medication not checked
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Concealed randomisation using computer generated randomisation envelopes."
Allocation concealment (selection bias)	Low risk	Envelopes sealed as above
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	No patients lost to long term follow up (mean 59 months)
Selective reporting (reporting bias)	Low risk	All stated outcomes reported
Other bias	Low risk	No other obvious bias