What does vascular protection mean for patients with peripheral artery disease?
While the treatment of coronary artery disease (CAD) has progressed dramatically over the past 50 years, peripheral artery disease (PAD) treatment has faced several issues:
- Under-diagnosis of PAD
- A lack of effective treatments for in PAD
- A failure to treat diagnosed patients in line with current best practice
Estimates indicate that over half of patients with PAD are asymptomatic,1 while 10–35% present with intermittent claudication2 – a feeling of tightness or ‘pins and needles’ in the leg which is often disregarded by the patient. These factors mean that patients frequently remain undiagnosed until the disease is very advanced – over half of patients undergoing major amputation for critical limb ischaemia may have had no ischaemic symptoms at all as little as six months earlier.3
Even after diagnosis of PAD, treatment options remain limited. Current guidelines recommend that patients with PAD are treated with an antiplatelet agent (either acetylsalicylic acid [ASA] or clopidogrel) in combination with a statin and, where indicated, angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) to manage blood pressure4. The recommendation to consider antithrombotic therapy with clopidogrel is based on a subanalysis of the CAPRIE trial in 19965; while several more recent clinical trials have included a PAD population,6-9 the PEGASUS trial for ticagrelor in patients with a history of myocardial infarction (MI) showed an improvement in the risk of major adverse cardiovascular (CV) events in the PAD subgroup.10 All of these trials indicate a high residual risk of major CV events, with ~1 in 10 patients experiencing a major CV event over the 2.5–3-year follow-up period.6,8-10
While patients in clinical trials usually receive guideline-recommended therapies for vascular protection, real-world data suggest that these strategies are underutilized in patients with PAD. In REACH, ~1 in 5 patients with PAD did not receive an antiplatelet agent, and almost 1 in 3 did not receive a statin. Other data indicate an even lower use of guideline-recommended therapies – in a survey of US patients with PAD attending outpatient clinics between 2006 and 2013, just over one-third of patients received an antiplatelet or a statin.11
Together, these data demonstrate an urgent need to improve vascular protection strategies in patients with PAD. Over 80% of patients with PAD are current or former smokers and 12–20% have diabetes12, making smoking cessation and diabetes control crucial in managing the disease. Meanwhile, clinical trials continue to investigate new therapeutic strategies in this population, and as more data becomes available there is hope that these may significantly reduce CV risk in these patients.