Scharn 2008.

Methods	Site: AK Study design: RCT Method of randomisation: controlled by the BOA‐trial agency using a dedicated computer program Blinding: unblinded, intention to treat Exclusions post randomisation: 8 (6%) Losses to follow up: 13 (9%)
Participants	Country: the Netherlands Setting: hospital No. of participants: 137 (137 limbs with 8 excluded; 59 HBD, 70 HUV) Age (median): 65 yrs Sex: 87 males, 50 females Inclusion criteria: severe claudication, rest pain, tissue loss Exclusion criteria: patients younger than 30 or older than 90 yrs of age; patients with an ABI higher than 0.8 at rest, emergency surgery for trauma, acute thrombosis or embolism of the popliteal artery, the diagnosis or treatment for malignancy within 12 months, hospital in‐patient treatment for cardiac failure in the previous 6 months, the absence of the possibility for adequate follow up or contraindications for anticoagulant drug therapy
Interventions	Heparin bonded Dacron and HUV (diameter at discretion of operating surgeon) Aspirin 80 mg daily or coumarin derivates (Sintrom)
Outcomes	Primary patency. 5‐year follow‐up
Notes	No consistent anticoagulation protocol. No compliance checks
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was controlled by the BOA‐trial agency using a dedicated computer program."
Allocation concealment (selection bias)	Low risk	Not specifically stated but assumed done as BOA‐trial agency involved
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 losses, clear life table data
Selective reporting (reporting bias)	Low risk	All stated outcomes reported
Other bias	Unclear risk	No consistent anticoagulation protocol