Vriens 2013.
| Methods | Site: Femoral to AK popliteal Study design: multicentre RCT Method of randomisation: concealed randomisation using sealed envelopes in blocks of 4 per centre Blinding: unblinded, as treated analysis Exclusions post randomisation: 1 (0.4%) Losses to follow up: 4 (1.5%) Protocol violations: 1 (1 ‐ crossover from allocated group) |
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| Participants | Country: 6 centres in the Netherlands Setting: hospital No. of participants: 266 (136 externally supported polyester, 129 non‐externally supported polyester, 1 not treated according to protocol so excluded) Age (median): 65 yrs in externally supported group, 67 in non externally supported group Sex: 199 males, 66 females; 1 excluded Inclusion criteria: all patients requiring AK femoro‐popliteal bypass for disabling claudication, rest pain, tissue loss in the absence of a suitable venous conduit Exclusion criteria: no suitable distal anastomotic target, distal anastomosis not above knee, previous ipsilateral femoro‐popliteal procedures, contra‐indication for the use of acetyl salicylic acid or anticoagulants, patients receiving chemo‐ or radiotherapy, malignancy diagnosed or treated within 12 months, known allergy to iodine or contrast medium, and impaired renal function |
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| Interventions | Fluoropassiv 6 mm knitted polyester, either externally supported thin‐wall fluoropolymer coated or 6 mm externally unsupported thin wall | |
| Outcomes | Primary endpoints: primary patency at 1 and 2 years post‐op. Secondary endpoints: mortality, primary assisted and secondary patency | |
| Notes | Clear anticoagulation protocol. Clear numbers of patients throughout (flow chart) | |
| 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 4 patients (1.5%) were lost to follow‐up |
| Selective reporting (reporting bias) | Low risk | All stated outcomes reported |
| Other bias | Low risk | Good anticoagulation protocol. Clear numbers of patients throughout (flow chart) |
ABI: ankle brachial index AK: above knee ASV: autologous saphenous vein BK: below knee CABG: coronary bypass graft CFA: common femoral artery DM: diabetes mellitus HBD: heparin bonded Dacron HUV: human umbilical vein IC: intermittent claudication LSV: long saphenous vein MALE: major adverse limb events MI: myocardial infarction POD: peri‐procedural death post‐op: post‐operative/operatively pt: patient PTFE: polytetrafluoroethylene PUR: polyurethane RCT: randomised controlled trial SFA: superficial femoral artery yrs: years