Peripheral Artery Disease: To Screen or Not Screen, That Is the Question!

Peripheral artery disease (PAD) is associated with an increased risk of cardiovascular disease (CVD); therefore, early diagnosis is important. Diagnostic tests should achieve an early diagnosis of PAD in those who are asymptomatic. Thus, noninvasive techniques play a key role, and ultrasound (US) has shown diagnostic capability, sensitivity, and specificity and is regarded as a mandatory investigation for PAD. Computerized scan and nuclear magnetic resonance have also been used to diagnose PAD. Although these latter imaging techniques are expensive and not easily repeatable, they result in more sensitivity and specificity than US in detecting arterial stenosis >50%. The worldwide prevalence of PAD based both on clinical investigation and ankle–brachial index (ABI) measurement ranges between 2% and 3% and up to >15% in the general population or in hospitalized cohorts. Studies performed in Italy based on the ABI have shown a variable prevalence of PAD, possibly attributed to differences in socioeconomic and lifestyle characteristics between populations living in different regions of Italy. Apart from US, the ABI is an easy tool for PAD diagnosis. Recording hemodynamic imbalance is crucial in planning prevention against arterial disease progression and lowering the risk of progressive arterial involvement. Atherosclerosis is a progressive process; it follows that a number of patients with atherosclerotic disease (eg, PAD) die from CVD events (eg, myocardial infarction or stroke). According to the TransAtlantic Inter-Society Consensus statements, patients with PAD have a high CVD morbidity and mortality (30 of 100 patients with PAD) within 5 years. Furthermore, a number of those patients (5 of the 30) die from cardiac events. These data led professional societies to suggest using the ABI test as a noninvasive screening method and an easy and reproducible diagnostic test (Table 1). The ABI shows a diagnostic reduction in peripheral arterial pressure and plays a role in planning the early and effective management of PAD. Patients with PAD may receive both medical and revascularization therapy. In this context, the ABI can help assess PAD prognosis in terms of both the fate of the artery and the CVD outcome. The ABI is simple to apply and it can be used in general practice. Recent studies demonstrated the efficacy of ABI to screen general populations for PAD. Many patients aged 55 to 65 years are often not aware of their arterial ‘‘status. ’’ Patients with a reduced ABI ( 0.99-0.90) should have a noninvasive US test. Italian patients with PAD have a higher Framingham risk score than those without PAD (14 vs 10), and those at a higher percentage were at a high risk (23.9% vs 13.6%) of CVD. Because arterial elastic properties influence the ABI, calcification of the arterial wall may limit its use as a diagnostic test. Furthermore, older age, diabetes, chronic renal failure, and systemic and chronic inflammatory disease can impair the elastic properties of the arterial wall. Arterial stiffness and media calcinosis are present in diabetes and renal failure and limit the use of the ABI to diagnose PAD. Therefore, alternative techniques (eg, photoplethysmography and toe–brachial index) may be needed to diagnose PAD. However, the strengths of ABI are that it is cheap, easy to perform, repeatable, and helpful to monitor outcomes. Recent research has focused on the potential role of inflammatory biomarkers in PAD. Several biomarkers (eg, C-reactive protein, interleukins, soluble vascular adhesion molecule-1, and intercellular adhesion molecule-1) are elevated in the plasma of patients with PAD. These markers may help better identify higher-risk patients with PAD. However, circulating biomarkers should be specific, sensitive, and address the following: (a) multifactorial pathophysiology of PAD includes hemodynamic disturbance, tissue damage, and cell dysfunction, (b) the association between hemodynamic lack and cell dysfunction, and (c) biomarkers may help to monitor the effects of established medical options and new treatments (eg, targeted cell therapy). Finally, markers should be easy to measure, cost-effective, and based on reliable methodology. The value of these vascular biomarkers in routine clinical practice is unclear. We need to stress the high prevalence of PAD particularly in older patients and consider several interesting questions. First, the increased average life span is potentially associated with a rise in the prevalence of PAD. Second, there are many patients with undiagnosed PAD because of low awareness and reduced