The worldwide burden of peripheral artery disease

Transcription

1 The worldwide burden of peripheral artery disease The role of the physician Based on the Inter-Society Consensus Edited by Dr Kenneth Harris The University of Western Ontario, London, Ontario, Canada Supported by an educational grant from Mitsubishi Tanabe Pharma Corporation. Mitsubishi Tanabe Pharma Corporation was not involved in the development of this pocket guide and in no way influenced its contents.

2 CONTENTS Introduction 4 Epidemiology of PAD 5 Frequent co-morbidities 8 The need for amputation in patients with PAD 12 The high mortality rate of patients with PAD 16 Survival of patients with PAD 18 Conclusion 21 References 22 3

3 Introduction The term peripheral artery disease (PAD) is used to refer to the obstruction of blood flow in the arteries, but does not include coronary and intracranial vessels. 1 PAD can result from atherosclerosis, an embolism, thrombus formation or inflammatory processes leading to arterial Peripheral arterial disease (PAD) in the legs, sometimes known as peripheral vascular disease, is frequently caused by atheroma (fatty deposits) in the walls of the arteries, leading to insufficient blood flow to the muscles and other tissues. stenosis. PAD is a major healthcare issue worldwide and patients with PAD have an increased risk of mortality, myocardial infarction and cerebrovascular disease. 2 The Epidemiology of PAD General PAD 3-6 predicted increase in the prevalence of PAD will intensify the demands placed on the healthcare services around the globe. There is therefore a pressing need within the healthcare system to commence an effective therapeutic strategy for treating patients with PAD. As it is primary care physicians that are predominantly involved in managing the day-to-day treatment of patients with PAD, this burden will be primarily felt by them. The severity of patients leg symptoms and atherosclerosis must be taken into account in order to provide them with an optimal standard of care. The objective of this booklet is to highlight the epidemiology of PAD and discuss the role It is estimated that 27 million individuals in Europe and North America have PAD Risk factors for atherosclerosis fall into two categories: Modifiable: cigarette smoking, diabetes, dyslipidemia, hypertension, and hyperhomocysteinemia Non-modifiable: race, age, and gender In Europe and North America, there are 413,000 hospital discharges of patients with chronic PAD per year; 88,000 hospitalizations involving lowerextremity arteriography and 28,000 discharges of physicians in providing their patients with an effective citing embolectomy or thrombectomy of lower-limb 4 treatment strategy. arteries in US hospitals alone 5

4 The prevalence of PAD has been evaluated in several epidemiologic studies and is in the range of 3 10%, increasing to 15 20% in people aged over 70 years old Asymptomatic PAD 3,7,8 An estimated 10.5 million people have symptomatic PAD but the majority of patients, 16.5 million, have asymptomatic disease One-third of patients with asymptomatic PAD have complete occlusion of a major leg artery According to the National Health and Nutritional Examination study, the prevalence of PAD in the asymptomatic population is: 2.5% in the year-old age group 14.5% in the >70-year-old age group The most widely used test to detect asymptomatic PAD is the ankle-brachial systolic pressure index (ABI). This test has a sensitivity of approximately 95% for detecting PAD Symptomatic PAD 6 The main symptom of PAD is intermittent claudication (IC). IC is characterized by muscle discomfort in the lower limb, which is reproducibly produced by exercise and relieved by rest within 10 minutes The prevalence of IC increases from 3% in patients aged 40 years, to 6% in patients aged over 60 years. Figure 1 shows the calculated weighted mean prevalence of IC in different age groups In younger patients, claudication is more common in men than women. In older patients, no apparent gender bias has been observed Between 10% and 50% of patients with IC have never consulted a doctor about their symptoms Only approximately 25% of patients with PAD are undergoing treatment for the condition. This low percentage is largely attributable to the fact that the general population is largely unaware of the condition 6 7

5 Figure 1. Weighted mean prevalence of intermittent claudication (symptomatic PAD) in large populationbased studies 6 Prevalence (%) The PAD Awareness, Risk, and Treatment: New Resources for Survival (PARTNERS) program was initiated to assess the feasibility of detecting PAD in primary care clinics. In this study, the prevalence of PAD and cardiovascular disease (CVD) was assessed in 6979 at-risk patients (Figure 2) Figure 2. The number of patients diagnosed with PAD and cardiovascular disease (CVD) in the PARTNERS study Age-group 6979 patients screened Frequent co-morbidities Complete data set for 6417 patients Coronary artery disease 6,9, % of patients with PAD also have coronary CVD only 1527 patients (23.8%) PAD and CVD 1040 patients (16.2%) PAD only 825 patients (12.9%) artery disease (CAD) and cerebral artery disease 10 30% of patients with CAD also have PAD The Reduction of Atherothrombosis for Continued Health (REACH) registry collected data on The extent of CAD correlates with a patient s ABI atherosclerosis risk factors and treatment. The prevalence of PAD, CAD, and cerebral artery disease was investigated in a total of 67,888 patients from physician practices in 44 countries (Figure 3) 9

6 Figure 3. Typical overlap in vascular disease. 6 Based on the REACH registry 9 Coronary artery disease 44.6% Cerebral artery disease 6,9 4.7% 8.4% 1.6% 1.2% PAD 4.7% Cerebral artery disease 16.6% Renal disease % of patients with PAD have 50% renal artery stenosis Renal artery stenosis of 50% is associated with a 3.3-fold higher mortality rate than in the general population Owing to the fact that PAD, CAD, and cerebral artery disease are all manifestations of atherosclerosis, it is not surprising that the three conditions commonly occur together 26 50% of patients with IC have carotid artery disease 5% of patients with PAD will have a cerebrovascular event In the REACH registry, out of those patients with symptomatic PAD (Figure 3): 1.2% had cerebral artery disease 1.6% had CAD and cerebral artery disease 10 11

7 The need for amputation in patients with PAD Clinical studies have shown that PAD progression is identical, regardless of whether the patient has symptomatic or asymptomatic disease. The development of symptoms depends largely on the activity level of the subject. Intermittent claudication 6 Only about one-quarter of patients with IC will ever experience symptomatic deterioration. Major amputation is rarely required in patients presenting with claudication. Only 1 3.3% of patients with IC require amputation over a 5-year period (Figure 4). A changing ABI is probably the best individual predictive factor for assessing a patient s deterioration. Patients with an abnormal ABI of <0.50 are over twice as likely to deteriorate as patients with an ABI of >0.50. Patients with intermittent claudication can be reassured that amputation is an unlikely treatment outcome Figure 4. Fate of the patient with intermittent claudication over 5 years 5 Asymptomatic PAD 20 50% Stable claudication 70 80% Natural history of atherosclerotic lower extremity PAD syndromes PAD population (50 years and over) Initial clinical presentation Limb morbidity Worsening claudication 10 20% Other leg pain 30 40% 5-year outcomes Critical limb ischemia 5 10% Amputation Typical claudication 10 35% Alive with two limbs 45% Critical limb ischemia 1 3% Non-fatal cardiovascular event (MI or stroke) 20% 1-year outcomes Amputation 30% CV morbidity and mortality CV causes 75% Mortality 10 15% CLI: critical limb ischemia; CV: cardiovascular; MI: myocardial infarction. Reproduced with permission Mortality 25% Non-CV causes 25% 12 13

8 Critical limb ischemia (CLI) 6,11 CLI is defined as chronic ischemic rest pain, ulcers or gangrene attributed to objectively proven severe arterial occlusive disease. There are approximately 220 new cases of CLI per million people every year in Europe and North America. Given the high rate of gangrenous progression in untreated patients, the majority of patients undergo revascularization therapy to treat CLI (Figure 5). However, amputation can be considered as a therapeutic option in the management of patients who have an overwhelming infection that threatens their life or when rest pain cannot be controlled. In Europe and North America, approximately amputations are performed per million people per year. There are approximately 220 new cases of CLI per million people every year in Europe and North America Figure 5. Fate of patients presenting with CLI 6 Acute limb ischemia (ALI) 6,12 ALI occurs as a result of a sudden decrease in the blood flow to a limb, resulting in a potential threat to the viability of the extremity. There are approximately 140 cases of ALI per million people per year. In Europe and North America, patients presenting with ALI have a particularly severe short-term prognosis in terms of loss of the leg and mortality. Clinical studies have reported a 30-day amputation rate of between 10% and 30%. 14 The dismal 1- to 2-year prognosis for patients who have undergone below-knee amputation is shown in Figure 6. 15

9 Figure 6. Fate of the patient with below-knee amputation 6 The most common cause of death is CAD. Approximately 63% of deaths are the result of CAD, 9% from cerebrovascular disease, and 8% are the result of other cardiovascular events, such as ruptured aneurysms 13 Approximately 20% of patients with chronic CLI die within the first year after presentation. Long-term data suggest that mortality continues at a higher rate than for patients with IC and controls 6 (Figure 7) The high mortality rate of patients with PAD Although few deaths are directly attributed to PAD, the prevalence of the disease is a strong predictive factor for CAD and cerebrovascular disease mortality 4 The 5-, 10-, and 15-year mortality rates for patients with symptoms of IC are approximately 30%, 50%, and 70%, respectively 6 The short-term mortality of patients with ALI is between 15% and 20% 6 Patients with PAD have an overall major cardiovascular event rate of approximately 5 7% 6 The annual incidence of non-fatal myocardial infarction is between 2% and 3% for patients with PAD

10 Survival of patients with PAD 6 On average, the mortality rate of IC patients is 2.5 times Key points providing effective treatment for patients with PAD higher than that of non-claudicant patients (Figure 7). Additionally, patients with CLI have a 20% mortality rate in the first year after presentation: the little long-term data that exist suggest that the mortality of CLI patients continues at approximately the same rate. 6 Primary care physicians are in a pivotal position within the healthcare system to improve the standard of care for patients with PAD. This improvement can be achieved by physicians through a series of proactive steps: 18 Figure 7. Survival of patients with PAD 6 Survival (%) CLI Follow-up (years) IC: intermittent claudication; CLI: critical limb ischemia Controls IC 15 The 5-, 10-, and 15-year mortality rates for patients with IC are approximately 30%, 50% and 70%, respectively Increase patient awareness of PAD and its consequences. Due to a lack of patient understanding, only approximately 25% of patients with PAD are currently undergoing treatment for this condition Increase the rates of early detection among the asymptomatic population. As most patients with PAD have asymptomatic disease, this aim can be achieved by measuring the patient s ankle brachial index (ABI). A simple and inexpensive form of diagnostic assessment, ABI testing requires only a blood pressure cuff and a Doppler ultrasonic sensor to reliably identify lower-extremity PAD in asymptomatic patients 19

11 Improving the identification of patients with symptomatic PAD. This goal can be attained by ensuring that physicians are well informed about PAD prevention, detection, and management. The updated version of the Inter-Society Consensus (TASC II) guidelines has been developed with this aim in mind. The guidelines have been prepared to provide vascular specialists and physicians alike with an international consensus on the diagnosis and treatment of PAD. For further information on the guidelines please visit the TASC II website: Identify high-risk individuals through the use of a screening program Improve treatment rates among patients who have been diagnosed with symptomatic PAD. A stepwise treatment approach has been shown to provide patients with the most effective care Conclusion With a prevalence of approximately 27 million people in Europe and North America, PAD is a critical public health issue. Due to worldwide demographic changes towards an aging population, the prevalence of PAD is likely to increase dramatically over the next 20 years. The long-term prognosis for patients with PAD is very poor; only 30% of patients are still alive 15 years after being diagnosed with the disease. The day-to-day responsibility of treating patients with PAD rests on the shoulders of physicians. By adopting the recommendations developed by the Trans-Atlantic Inter-Society Consensus (TASC) working group, it is anticipated that physicians will be able to easily diagnose PAD and provide their patients with an effective therapeutic strategy. With a prevalence of approximately 27 million people in Europe and North America, PAD is a critical public health issue 20 21

12 References 1. Ouriel K. Peripheral arterial disease. Lancet 2001; 358(9289): SIGN. Diagnosis and management of peripheral arterial disease. A national clinical guideline Belch JJ, et al. Critical issues in peripheral arterial disease detection and management: a call to action. Arch Intern Med 2003; 163(8): Golomb BA, et al. Peripheral arterial disease: morbidity and mortality implications. Circulation 2006; 114(7): Hirsch AT, et al. ACC/AHA 2005 guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic). J Am Coll Cardiol 2006; 47(6): Norgren L, Hiatt WR, et al. Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II). Available at: Accessed October 2007.* 7. Fowkes FG, et al. Edinburgh Artery Study: prevalence of asymptomatic and symptomatic peripheral arterial disease in the general population. Int J Epidemiol 1991; 20(2): Selvin E, Erlinger TP. Prevalence of and risk factors for peripheral arterial disease in the United States: results from the National Health and Nutrition Examination Survey, Circulation 2004; 110(6): Bhatt DL, et al. International prevalence, recognition, and treatment of cardiovascular risk factors in outpatients with atherothrombosis. JAMA 2006; 295(2): Hirsch AT, et al. Peripheral arterial disease detection, awareness, and treatment in primary care. JAMA 2001; 286(11): Jaccard Y, et al. Influence of secondary infection on amputation in chronic critical limb ischemia. Eur J Vasc Endovasc Surg 2007; 33(5): Dormandy J, et al. Acute limb ischemia. Semin Vasc Surg 1999; 12(2): Regensteiner JG, Hiatt WR. Current medical therapies for patients with peripheral arterial disease: a critical review. Am J Med 2002; 112(1): *Also published as follows: J Vasc Surg 2007; 45(Suppl S): S5 67. Eur J Vasc Endovasc Surg 2007; 33(Suppl 1): S Int Angiol 2007; 26(2):

13 TASC II Inter-Society Consensus for the Management of PAD This pocket guide is one of a series of booklets designed to present the TASC II guidelines in a quick reference format. You can find pocket guides on other topics covered in the TASC II guidelines on the TASC II website: Discovery London and TASC II. All rights reserved.