This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Blockages in leg arteries restrict blood flow to the lower leg and foot; people with severely restricted blood flow to the legs are at high risk of amputation or death. This is called chronic (long-term) limb threatening ischaemia.
The BASIL-2 randomised controlled trial compared two approaches to restoring blood flow (revascularisation) to the leg when the blockages are below the knee. It found that opening up blocked arteries with balloons or stents (endovascular therapy) resulted in better outcomes than bypassing the blockages using the person’s own vein (vein bypass).
BASIL-2 included 345 people with chronic limb threatening ischaemia. Participants were suitable for receiving either revascularisation strategy (endovascular therapy or vein bypass) first. Fewer of those who received endovascular therapy (53%) died or had a major (above the ankle) amputation than in the bypass group (63%). This was mainly due to fewer deaths in the endovascular group (45%) than in the bypass group (53%). The number of amputations was similar in both groups (18% for endovascular and 20% for bypass).
These findings are relevant for people with chronic limb threatening ischemia who need a revascularisation and are eligible for either approach. The findings will inform shared decision-making between clinicians and patients about which is best for them.
What’s the issue?
In people with peripheral arterial disease, fatty deposits narrow or block arteries and restrict blood flow to one or both legs. The condition is common, especially among those who smoke and have diabetes, high blood pressure or high cholesterol levels.
The most severe form of peripheral arterial disease is called chronic limb threatening ischaemia. People with chronic limb threatening ischaemia typically have pain in the foot at rest, and/or suffer with and ulcers and gangrene, or both. Unless the blood supply is restored, they are at high risk of amputation or death.
Blood supply can be restored either by opening up blocked arteries with balloons or stents (endovascular therapy) or bypassing the blockages using the patient’s own vein (vein bypass). In people who are potentially suitable for both, there is debate over which to offer first.
Two previous trials (BASIL-1 and BEST CLI) suggested that bypasses had better outcomes (fewer deaths) compared with endovascular treatment. However, they both mainly included people who needed revascularisation above the knee.
BASIL-2 is the first randomised controlled trial to compare vein bypass with endovascular therapy as the first strategy for people who need revascularisation of arteries below the knee.
What’s new?
The study included 345 people with chronic limb threatening ischaemia who attended hospitals in the UK (39), Denmark (1) or Sweden (1). Most (81%) were men and the average age was around 73. Participants were randomly assigned to receive below the knee endovascular treatment (173) or vein bypass (172) first. They were followed-up for more than 3 years on average.
The main outcome was the number of people who remained alive without a major (above the ankle) amputation during the follow-up period.
The study found that:
- fewer people in the endovascular group (53%) had a major amputation or died than in the bypass group (63%)
- this was mainly because fewer people in the endovascular group (45%) died than in the vein bypass group (53%)
- the number of people requiring amputations was similar in the endovascular (18%) and vein bypass (20%) groups.
In both groups, the most common causes of death were diseases of the heart, lungs, and blood vessels.
Why is this important?
BASIL-2 included people with chronic limb threatening ischaemia who needed revascularisation below the knee, and were suitable for both strategies. It found that offering endovascular therapy first led to better outcomes than offering vein bypass first.
These findings will inform shared decision making between clinicians and people with chronic lower leg ischaemia about which revascularisation strategy is best for them.
The researchers say their findings need to be considered alongside the BEST CLI results. However, there were key differences between this trial and BEST CLI, they say.
What’s next?
The BASIL-2 researchers have a data-sharing agreement with the BEST-CLI investigators to allow ongoing collaborative research (including an individual patient data meta-analysis).
A related study in the BASIL project included 471 people who presented consecutively to the trial centre in Birmingham with chronic limb threatening ischaemia. The researchers sought to understand how typical the BASIL-2 participants are of those with chronic limb threatening ischaemia, and how they compare to people having below the knee revascularisation for this condition outside of the trial.
You may be interested to read
This is a summary of: Bradbury AW, and others. A vein bypass first versus a best endovascular treatment first revascularisation strategy for patients with chronic limb threatening ischaemia who required an infra-popliteal, with or without an additional more proximal infra-inguinal revascularisation procedure to restore limb perfusion (BASIL-2): an open-label, randomised, multicentre, phase 3 trial. Lancet 2023; 401: 1798 – 809.
An article about the trial from Endovascular Today.
A webinar discussing the study findings from YouTube.
A podcast about the study from the British Journal of Surgery.
Funding: this study was funded by the NIHR Health Technology Assessment programme.
Conflicts of Interest: See paper for full disclosures.
Disclaimer: Summaries on NIHR Evidence are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that the views expressed are those of the author(s) and reviewer(s) at the time of publication. They do not necessarily reflect the views of the NHS, the NIHR or the Department of Health and Social Care.
