Klinkert 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: 11 (7%)
Participants	Country: the Netherlands Setting: hospital No. of participants: 136 (151 limbs; 75 Saphenous vein, 76 PTFE) Age (median): 69 yrs Gender: 88 males, 48 females Inclusion criteria: severe claudication, rest pain, tissue loss Exclusion criteria: patients with earlier bypass or previously removed long saphenous vein
Interventions	6 mm PTFE and reversed vein graft Oral warfarin from one day pre‐op continued for 6 months. 38 mg aspirin afterwards
Outcomes	Primary and secondary patency 5‐year follow up
Notes	No compliance checks
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Unclear. No specific description
Allocation concealment (selection bias)	Low risk	Quote: "randomization took place with closed envelope allocation."
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	13 patients lost to long term follow up, clearly described
Selective reporting (reporting bias)	Low risk	All stated outcomes reported
Other bias	Low risk	Oral warfarin from one day pre‐op continued for 6 months. 38mg aspirin afterwards