Overview of the BASIL-2 Trial

The treatment options for severe limb ischaemia (SLI) are vein bypass (VB), endovascular intervention including angioplasty (the use of a balloon inside the artery) and stenting (the insertion of small metal cage to keep the artery open), amputation and end-of-life care.

BASIL-2 is an individually randomised, multi-centre, pragmatic, two-arm, open trial of two alternative revascularisation strategies: VB first vs. Best Endovascular Treatment (BET) first, for the management of SLI due to infra-politeal disease, with or without the presence of femoro-politeal, disease. The trial incorporates an internal pilot phase and within-trial economic evaluation.

BASIL-2 will recruit 389 patients with SLI from the UK, Denmark and Sweden until end of November 2020 (approval for amendment from REC/HRA will be sent to local R&Ds). Patients will be followed up for a minimum of two years after their intervention. Patients will be randomised, 1:1, to have either vein bypass or endovascular intervention as their first trial treatment. Subsequently, they may have additional interventions as per clinical choice. That is, some may have the same type of procedure as their original randomised allocation on several occasions whilst others may have a different procedure and others may go on to have a mixture of the two.

Recovery time from surgery and endovascular intervention is often prolonged and caring for patients with SLI is extremely costly to NHS and social care services, so patients will be asked to complete questionnaires on their quality of life, attitudes to their life and the personal impact upon their finances. Wider financial impact will be assessed via a Health Economic Analysis.

To determine whether a ‘VB first’ or a ‘BET first’ revascularisation strategy represents the most clinically and cost-effective treatment for SLI due to IP +/- FP arterial disease.

Recruitment will be from hospitals across England, Scotland, Wales, Sweden, and Denmark.

Any patients over the age of 18 with a diagnosis of severe limb ischaemia due to infra-popliteal disease (with or without the presence of femoro-popliteal disease) and who, in the opinion of a suitable multi-disciplinary team require early revascularisation.

Best Endovascular Treatment (BET)

Patients randomised to BET will undergo the procedure that the responsible consultant vascular surgeon or interventional radiologist believes is the most appropriate given the individual patient’s clinical and disease pattern characteristics. The options are Plain Old Balloon Angioplasty (POBA ) with or without a Bare Metal Stent (BMS) should it be required; POBA with or without a Drug Eluting Stent (DES); a Drug Eluting Balloon (DEB) +/-  BMS; DEB +/- ‘bail-out’ DES; primary BMS and primary DES. In the great majority of cases, regardless of the exact technique / devices being used, the procedure will be performed under local anaesthetic via an ultrasound-guided puncture of the CFA; occasionally intravenous sedation may be given and, rarely, a GA may be required. BET success will be established by post-intervention completion angiography, palpation of foot pulses and measurement of ABPI and TBPI.

Vein Bypass (VB)

VB will be performed using standard anaesthetic and surgical techniques and equipment. Pre-operative Doppler Utrasound-based vein mapping is UK ‘standard of care’ and will be performed in all cases to determine the presence of a suitable (optimal) venous conduit for VB. This conduit will normally be the ipsilateral or contralateral great saphenous vein but the use of small saphenous vein and arm vein will be permitted as they are recognised techniques forming part of current UK ‘standard of care’. In the unlikely event that the surgeon discovers intra-operatively that prosthetic material will be required then this will, of course, be permitted (rather than abandon the surgery) and noted.

Primary Outcome

Amputation free survival, AFS, defined as the time to major limb (above the ankle) amputation of the index (trial) limb or death from any cause.

Secondary Outcomes

• Overall Survival
• In-hospital and 30-day morbidity and mortality.
• Major Adverse Limb Events (MALE) amputation (transtibial or above) or any major vascular re-intervention in the trial leg(thrombectomy, thrombolysis, BA, stenting, or surgery) (trial leg)
• Major cardiovascular events (MACE): SLI and amputation affecting the contralateral limb, acute coronary syndrome (ACS), stroke
• Relief of ischaemic pain (VAS, medication usage)
• Psychological morbidity (HADS)
• QoL using generic (EQ-5D-5L, SF-12, ICECAP-O) and disease specific (VascuQoL) tools
• Re- and cross-over intervention rates
• Healing of tissue loss (ulcers, gangrene) as assessed by the PEDIS and the WiFi scoring and classification systems
• Extent and healing of minor (toe and forefoot) amputations (also using PEDIS and WiFi)
• Haemodynamic changes; absolute ankle and toe pressures, ABPI, TBPI

108 out of 172 (63%) people in VB group had a major amputation or died, compared to 92 out of 173 (53%) people in BET group.  This means that a VB first strategy was associated with an increased risk of major amputation or death compared with a BET first strategy.  

This difference was mainly due to fewer deaths in the BET group. Cardiovascular and respiratory diseases were the most common causes of death in both groups. However, there were no single common causes of death in either group to explain the differences in number of deaths between the two groups.

Amputation outcomes were similar between the two groups.

Our findings suggest a greater role for best endovascular treatment first strategy in the management of patients with CLTI who require an infra-popliteal revascularisation to restore limb perfusion.

View our presentation at the Charing Cross International Symposium for more information,

You can also read the full results in The Lancet paper : Bradbury, Andrew W et al (2023) A vein bypass first versus a best endovascular treatment first revascularisation strategy for patients with chronic limb threatening ischaemia who required an infra-inguinal revasularisation procedure to restore limb perfusion (BASIL-2): an open-label, randomised, multicentre, phase 3 trial in The Lancet (online 25 April 2023)