Lower Limb Bypass

What is a lower limb bypass?

Peripheral arterial disease (PAD) is a restriction of the blood flow in the lower-limb arteries. It can severely affect a patient’s quality of life. The disease can affect various sites in the legs, and produces symptoms that vary in their severity from pain in the legs during exercise to persistent ulcers, or gangrene.

One of the treatments available for PAD involves a surgical procedure to remove the blockage from the artery (endarterectomy) or by using a bypass graft. A bypass graft is a surgical operation that involves attaching a graft (hollow tube that is able to carry blood) above the area of narrow or blocked artery and attaching it to an area below it. This provides a new path for the blood to travel to and improves the blood supply to the leg and foot.

What information is being published on lower limb bypass?

For each trust, we present the number of procedures they submitted to the NVR in the reporting period. The colour and symbol next to this number indicate the case ascertainment, which is the number of procedures the trust submitted compared to the total they carried out according to national data sources.

We also publish the average length of stay for patients undergoing a lower limb bypass procedure. The numbers in brackets are the typical range that patients will stay in hospital. The results for a particular trust can be seen in relation to the overall national length of stay.

The final row is the risk adjusted in-hospital survival rate for lower limb bypass for the trust. Again, this can be seen in comparison to the overall national survival rate.

The information on this website was published in November 2018.

What data is being used to produce the outcome information?

The results for lower limb bypass are based on procedures carried out between 1st January 2015 and 31st December 2017.

How are the data analysed?

The results have been risk adjusted for patient case-mix to ensure that NHS trusts that take on more difficult cases are not unfairly penalised. The reason for producing risk-adjusted outcomes is because the characteristics of patients treated by NHS trust will vary, and the outcome of care will be influenced by these characteristics – on average, outcomes are often worse for sicker patients. Risk adjustment allows us to take account of these factors.

For outcomes after lower limb bypass, we used a risk model that contained the patient factors: age at surgery, Fontaine score, anatomy of procedure, chronic lung disease and chronic renal disease.