Personalised Antiplatelet Therapy for Patients With Symptomatic Peripheral Arterial Disease

Peripheral arterial disease (PAD) is a condition where the blood vessels in the legs get blocked. It affects one out of every five adults over the age of 65. As it is the main cause of amputations, the NHS performs over 20,000 operations every year to prevent them. People with PAD benefit from tablets to thin their blood as this improves outcomes after surgery and prevents heart attacks and strokes. The main tablets for this purpose are aspirin and clopidogrel. These work in most people, but up to a third of patients do not get any benefit from them, as their bodies cannot process them. We call this resistance to therapy (RT).Because blood thinning is particularly important after operations people with RT may be at higher risk of their operation failing leading to amputation and/or problems such as heart attacks and strokes. Testing for RT has not traditionally been performed because it requires complex laboratory procedures. Recent development in technology now means that bedside tests are available for RT. We will use a simple beside test for RT in patients with severe PAD. We will use this test to see how many of these patients have RT and whether this affects their risk of complications after an operation. If we find that RT does affect outcomes for patients with PAD, the information obtained will be used to plan future research to determine if changing blood thinning therapy in people with CR improves their outcomes after surgery.