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For Immediate Release — April 28, 2003

New report highlights great unmet need in the diagnosis and treatment of Peripheral Arterial Disease (PAD)

April 28, 2003, 4:00 PM (EST) - A Call to Action to increase the awareness, detection and treatment of peripheral arterial disease (PAD) among healthcare professionals was published today in the Archives of Internal Medicine by the Prevention of Atherothrombotic Disease Network. The PAD Network is an independent, international, multidisciplinary group of specialists supported by a grant from the Sanofi-Synthelabo/Bristol-Myers Squibb Pharmaceuticals Partnership. PAD is characterized by arterial stenosis and occlusions in the peripheral arterial bed; it can be symptomatic or asymptomatic. Symptomatic PAD ranges in severity from intermittent claudication (IC) to critical limb ischemia. Regardless of symptomatology, PAD is an indicator of diffuse and significant atherothrombotic disease, and, therefore, of increased risk of myocardial infarctions (MIs) and strokes.

The report also highlights that PAD is grossly underdiagnosed in patients at high-risk of cardiovascular and cerebrovascular morbidity and mortality, despite the availability of an effective ten-minute diagnostic tool – the ankle brachial index (ABI).[i]

The Network, comprised of independent experts in the fields of vascular medicine, neurology, diabetology, nephrology, cardiology and primary care, has called for greater education for clinicians about the ischemic burden of PAD. The report also called for the initiation of greater improvement in the detection and treatment of PAD, a critical public health issue affecting more than 27 million people in Europe and North America.[ii] Regardless of whether symptoms are evident, patients with PAD have an increased risk of subsequent MI and stoke and are six times more likely to die within ten years than patients without PAD.[iii]

"PAD is a devastating disease affecting the lives of millions of people worldwide. It is imperative that an international awareness campaign be initiated to help improve the rate of diagnosis of PAD," said Professor Jill Belch, Chair of the Network, Ninewells Hospital and Medical School, Dundee, Scotland. "The initiation of an ABI screening program to identify those asymptomatic patients at high risk of PAD will help save lives," she added.

Recommendations for diagnosis and treatment

Recent developments in the diagnosis and management of PAD are the key drivers behind the publication. In particular, evidence supports the use of the ankle brachial index (ABI) as a diagnostic and risk assessment tool [iv],[v],[vi] and clinical data shows the substantial cardiovascular and cerebrovascular risk reduction that can be achieved through pharmacological intervention such as antiplatelet therapy[vii],[viii] and management of atherothrombotic risk factors including smoking, high blood pressure, high blood lipid levels and lack of exercise.

Intermittent claudication is the primary, and often only, clear symptom of PAD, however, an estimated 16.5 million of PAD patients do not experience any symptoms of the disease.[ix] In addition, one-third of patients with symptomatic PAD do not report their symptoms to their doctor believing symptoms to be a natural manifestation of the aging process. A number of recent studies designed to assess the rate of physician and patient awareness of PAD concluded that within the high-risk population, a significant amount of patients with PAD remain under-diagnosed.

The Call to Action paper notes that a data-derived screening protocol for high-risk patients is critical, since the majority of patients with PAD are asymptomatic and many symptomatic patients do not report their symptoms to a medical care provider. In addition, a recent US study has shown that clinicians who rely on a classic history of claudication alone to detect PAD will miss approximately 85% to 90% of patients with this high-risk atherothrombotic disease.[x]

 ABI measurement – an effective diagnostic tool

The authors highlight a large body of epidemiological evidence supporting the efficacy of the ankle brachial index (ABI) – a simple, non-invasive test – as a diagnostic and risk assessment tool for PAD.4 The ABI is measured by having the patient lie in the supine position, with subsequent performance of the ankle and brachial blood pressure measurements using a 5–7 mHz handheld Doppler device.

A diagnosis of PAD is based on an ABI measurement of <0.9. An ABI of <0.9 is also highly predictive of morbidity and mortality from atherothrombotic events such as MIs and strokes. The ABI test is a useful tool, as it not only provides clinicians with a means of identification of PAD, but also with information regarding the severity of PAD that can assist in guiding a treatment approach.

The authors outline a clinical profile of the population at risk for PAD, in whom directed screening is beneficial. Advanced age, smoking, and diabetes are strongly associated with PAD. In one study 50% of diabetic patients were found to have PAD.[xi]

Reducing risk in PAD with antiplatelet therapy

Authors of the Call to Action paper also evaluated the role of risk factor management and antiplatelet therapy (ASA & clopidogrel) in the prevention of atherothrombotic events associated with PAD. Risk factor control, including smoking cessation, high blood pressure control, high lipid level management and supervised exercise are all well-accepted and proven therapies in PAD.  All PAD populations appear to be under-treated in terms of these risk factors.  In addition, despite compelling evidence demonstrating the efficacy of antiplatelet agents in reducing vascular events in patients with atherothrombotic disease, a significant percentage of patients (30–40%) with diagnosed with PAD do not receive antiplatelet agents.[xii]

Clinical trial data show that clopidogrel has a statistically significant improved efficacy compared with ASA therapy in helping prevent atherothrombotic events associated with PAD. Data from the CAPRIE (Clopidogrel versus Aspirin in Patients at Risk of Ischemic Events) trial demonstrate that clopidogrel 75 mg/day provides a relative risk reduction in the composite endpoint of ischemic stroke, MI, or vascular death of 8.7% (P=0.043) over ASA 325 mg/day in patients with recent MI, recent stroke, or established PAD.  Clopidogrel showed a favorable safety and tolerability profile. 

Atherothrombosis

Atherothrombosis is the underlying condition that results in ischemic events – stroke, MI, and vascular death. A person suffering from any one manifestation of atherothrombosis (such as PAD) has a life-long risk of future disabling or potentially life-threatening events caused by the same underlying disease process.

Prevention of Atherothrombotic Disease Network

The Prevention of Atherothrombotic Disease Network, an international, multidisciplinary network is adjoined by the mutual goal of increasing awareness, detection, and treatment rates of peripheral arterial disease (PAD) and increasing awareness of the interrelationship between PAD and the risk of ischemic events.

The Network receives an unrestricted educational grant from the Sanofi-Synthelabo / Bristol-Myers Squibb partnership.

PAD – the five-item action plan

Dr Belch and the Prevention of Atherothrombotic Disease Network have outlined five key actions to address the current unmet need with respect to the treatment and diagnosis of PAD:

  1. Increasing awareness of PAD and its consequences (myocardial infarction, stroke, vascular death)
  2. Improving the identification of patients with symptoms of PAD
  3. Initiating screening for patients at high risk for PAD especially smokers, people with diabetes, people with a history of myocardial infarction and/or stroke
  4. Improving treatment rates among patients who have been diagnosed PAD
  5. Increasing the rate of early detection among the high-risk population without PAD.

Footnotes

[i] The Prevention of Atherothrombotic Disease Network. Critical issues in peripheral arterial disease detection and management: a call to action. Arch Int Med 2002. In press.

[ii] Weitz JI, Byrne J, Clagett GP et al. Diagnosis and treatment of chronic arterial insufficiency of the lower extremities: a critical review. Circulation 1996; 94: 3026–3049

[iii] Priollet P. Quality of life and peripheral arterial disease: perspectives for the future. Drugs 1998; 56(Suppl 3): 49–58.

[iv] Newman AB, Shemanski L, Manolio TA et al for the Cardiovascular Health Study Collaborative Research Group. Ankle-arm index as a predictor of cardiovascular disease and mortality in the Cardiovascular Health Study. Arterioscler Thromb Vasc Biol 1999; 19: 538–545.

[v] Papamichael CM, Lekakis JP, Stamatelopoulos KS et al. Ankle-brachial index as a predictor of the extent of coronary atherosclerosis and cardiovascular events in patients with coronary artery disease. Am J Cardiol 2000; 86: 615–618.

[vi] Sikkink CJ, van Asten WN, van't Hof MA, van Langen H, van der Vliet JA. Decreased ankle/brachial indices in relation to morbidity and mortality in patients with peripheral arterial disease. Vasc Med 1997; 2: 169–173.

[vii] Zusman RM, Chesebro JH, Comerota A et al. Antiplatelet therapy in the prevention of ischemic vascular events: literature review and evidence-based guidelines for drug selection. Clin Cardiol 1999; 22: 559–573.

[viii] Antiplatelet Trialists’ Collaboration. Collaborative overview of randomised trials of antiplatelet therapy. 1: prevention of death, myocardial infarction, and stroke by prolonged antiplatelet therapy in various categories of patients. BMJ 1994; 308: 81–106.

[ix] Dormandy JA. Epidemiology and natural history of arterial diseases of the lower limbs. Rev Prat 1995; 45: 32–36.

[x] Hirsch AT, Halverson SL, Treat-Jacobson D et al. The Minnesota Regional Peripheral Arterial Disease Screening Program: toward a definition of community standards of care Vas Med 2001; 6: 87–96.

[xi] Elhad TA, Robb R, Jung RT, Stoenbridge PA, Belch JJF. Pilot study of prevalence of asymptomatic peripheral arterial occlusive disease in patients with diabetes attending a hospital clinic. Pract Diabetes Int 199; 16: 163–166.

[xii] Belch JJF, oral presentation, 2001

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