Prof. V Pitruzella
Prof. Salvatore Novo,
Patients with PAD should be treated not only for the local problems - claudicatio intermittens, pain at rest and/or ulcers-, but also for the prevention of future vascular events. Prevention of future vascular events entails aggressive treatment of all risk factors as well as secondary prevention. To achieve this goal, we can now count on three pharmacological classes that seem truly effective : antiplatelet drugs, ACE-I as demonstrated in the HOPE study, and statins, especially.
a) Definition and risk factors
Peripheral arterial disease (PAD) of the lower limbs is the third topographic location of atherosclerosis (ATS) for frequency and severity of disability. Risk Factors (RF) are similar to those of coronary heart disease, but PAD is strongly related to cigarette smoking, diabetes, as well as with impaired glucose tolerance.
Other important risk factors are hypertension, hypercholesterolemia and low levels of HDL-cholesterol, high levels of triglycerides, apolipoprotein B, lipoprotein (a), hyperhomocysteinemia, hyperfibrinogenemia and blood hyperviscosity (1).
b) Incidence and prevalence
The incidence is approximately 2 to 1 for men over women. Women in most cases are affected by an almost asymptomatic form - if you exclude women with diabetes (1). The prevalence increases with age: 1% of men between ages 45 and 50, 3-3,5% of those over 50, more than 5% of men and 2.5% of women over 60 years are symptomatic for claudication intermittens (1).
The prevalence of PAD is higher if we consider asymptomatic patients with ABI < 0.90 as demonstrated by Hirsh et al. in the PARTNERS study, reaching 29% in those aged > 70 years or in adults aged 50-59 with important risk factors such as smoking or diabetes (2).
Functionally the disease is characterised by hypoperfusion of the lower limbs caused by arterial steno-occlusion in the iliac-femoral-popliteal district and, consequently, it will result in an altered relationship between oxygen demand and supply and metabolites in tissues (1).
This hypoperfusion induces a variety of clinical situations, ranging from asymptomatic disease, to the appearance of pain and ischemic muscle strain in claudication intermittens and critical lower limbs ischemia (CLI) with the presence of pain at rest, necrosis and gangrene (1). The appearance of symptoms is conditioned not only by the vascular steno-occlusion, but also by the development of collateral circles and the lifestyle of the patient. The progression of symptoms of PAD is relatively slow over time.
After 5 years of follow-up,
However, despite the fact that PAD prognosis is relatively benign for the affected limb, claudication intermittens must be always considered as a possible marker of multifocal atherosclerosis. It is very important to stress that patients suffering from PAD have an increased risk of developing coronary heart disease and cerebrovascular disease (1).
a) The ABI index
Because of the high risk of fatal and non-fatal cardiovascular events, patients with PAD should be subjected to a careful examination of the cardiovascular system in its entirety and to an aggressive correction of risk factors. An independent and significant indicator of mortality is the ankle-brachial index (ABI).
Generally, the lower the value of ABI, the higher the incidence of ischemic coronary and cerebral events and the lower survival is, as evidenced by the group of Diehm et al. (3) in the getABI Study, in which were followed for 5 years 6880 elderly subjects, aged > 65 years, with average age of 72.5 years, without PAD (79.2%), or with asymptomatic PAD and ABI < 0.90 (12.1%) and with symptomatic PAD (8.7% of the population). The mortality at 5 years was respectively 9,5%, 19.2% and 24.1% in the three groups. These results confirm the importance of symptomatic or asymptomatic PAD in increasing the cardiovascular risk in 10 years above 20% and therefore placing these subjects in a very high risk category (3).
b) Medical treatment and therapy
The goal of the treatment of PAD is to
Therapy is based on changes in lifestyle (cessation of smoking, regular physical exercise, a mediterranean diet) and on the control of RF;
Pharmacological treatment can offer
Antiplatelet drugs and statins
There are well-defined potential benefits of cardiovascular drugs in patients with PAD as recently demonstrated in a cohort, prospective, observational study involving 2420 patients with median age of 64 years (72% males) with PAD and ABI = or < 0.9 (4). 18% of the patients also suffered from diabetes, 24% had hypercholesterolemia, 35% were smokers, 48% suffered from hypertension, 44% from coronary heart disease and 9% had a history of heart failure. The average ABI was 0.58 (4). During an average follow-up of 8 years, 44% of patients died. After adjustment for RF, certain classes of drugs were associated with a reduced risk of mortality: statins, hazard ratio (HR) = 0.46; beta-blockers, HR = 0, 68; Aspirin, HR = 0.72; ACE-I, HR = 0.80 (4).
The 4S study (Scandinavian Simvastatin Survival Study) showed, for the first time, that in patients with coronary artery disease and hypercholesterolemia, followed with a follow-up of 5.4 years, treatment with simvastatin vs placebo, reduced 38% of the incidence of new cases of claudication intermittens and about 48% of cases of carotid atherosclerosis (7).
The SISOPAD study evaluated the effects of treatment with simvastatin in 283 patients of average age of 61 years at the second stage Leriche-Fontaine. After 1 year of treatment, the patients treated with simvastatin showed an improvement of ABI values versus the baseline values, a reduction in blood total cholesterol, an increase in HDL cholesterol, a significant reduction in blood plasma fibrinogen and a significant improvement in plasma viscosity (p < 0.01). The authors thought that treatment with simvastatin probably reduced the femoral-popliteal atherosclerosis with improving of the endothelial function (8).
A recent study published by Mondillo et al. (9) showed that treatment with simvastatin improves the performance of patients with PAD thanks to its effect on plaque stabilisation and on the improvement of the endothelial function. Eighty-six patients with intermittent claudication, and total cholesterol levels > 220 mg/dL were enrolled in a randomised, placebo-controlled, double-blind study. Forty-three patients were assigned to simvastatin (40 mg/d); the remaining 43 patients were assigned to placebo treatment. All patients underwent an exercise test and clinical examination, and completed a self-assessment questionnaire at 0, 3, and 6 months. At 6 months, the mean pain-free walking distance increased by 90 meters (95% confidence interval [CI]: 64 to 116 meters; P <0.005), in the simvastatin group versus the placebo group.
Aronow and coworkers, (10) in elderly patients (mean age 75 years) with PAD and ABI of 0.63 has shown that simvastatin, in comparison with placebo, increased walking time after 6 months of treatment. Specifically, in this study the authors have shown an increase of walking time at the treadmill of 54 sec. (+ 24%, p <. 0001) after 6 months and 95 sec. (+ 42%, p <. 0001) after one year.
Another study, conducted at Northwestern University Feinberg School of Medicine in Chicago, examined if the use of statins was associated with a smaller decline in the functioning of the lower limbs in patients with and without PAD, during a three year follow-up.
The study involved 332 men and women with ABI < 0.90 and 212 subjects with ABI between 0.90 and 1.50. After adjusting for various factors, patients with PAD who used statins had a lower annual decline in walking speed to normal step, in speed walking at fast pace, and in the process of testing than 6 minutes those who did not use statins. Data from the study showed that patients with PAD taking a statin may present a minor decline in the performance of the lower extremities (11).
The HPS study, which included 20,536 patients at high risk, has demonstrated the protective effect of chronic administration of simvastatin (40 mg/day) for 5 years in the subgroup of patients with PAD (n = 6748), with (n = 4042 ) or without (n = 2706) concomitant coronary artery disease, with a reduction major cardiovascular events of 22.3% (p < 0.00001) (12).
Researchers from the Vienna General Hospital have assessed the relationship between the use of statins, inflammation and outcome in patients with atherosclerosis at an advanced stage. 515 patients with severe PAD were studied in a prospective study. Patients were 70 years old on average, and 57% were male. The observation period was on average 21 months. There were 19 reported cases of myocardial infarction and 65 patients died. Patients (n=269, 52%) treated with statins had a lower level of inflammation, and improved survival compared with patients who have not taken drugs. However, patients with reduced inflammatory activity do not have any benefit from statin therapy, while patients with high levels of CPR (C-reactive protein) experienced a significant reduction in the risk of mortality (adjusted hazard ratio, HR: 0,58) and the composite risk of myocardial infarction and death (adjusted HR: 0.46). According to this study, treatment with statins is associated with a substantial improvement in medium-term survival in patients with severe PAD and high inflammatory activity (13).
Aronow & Ahn studied the frequency of new coronary events in 660 elderly patients with PAD (mean age 80 ± 9) and serum levels of LDL-C > 125 mg%, treated or not treated with lipid lowering drugs and followed for a period of 39 months. Within the two groups, the following events were recorded: sudden death 19% vs 31%, IMA fatal 16% vs. 25%, IMA non-fatal 13% vs 18%, all new coronary events 48% vs. 73% (p < 0.0001) (14). Consequently, long-term administration of statins in patients with PAD is extremely useful in reducing the incidence of fatal and non-fatal cardiovascular and cerebrovascular events during follow-up.
c) Recommendations of different guidelines in the use of statins in patients with PAD
The National Cholesterol Education Programme-Adult Treatment Panel III (NCEP-ATP III) Guidelines consider patients with PAD as a high-risk group. The report identifies
- an optimal level of LDL-cholesterol <100 mg / dl and lays down a level of HDL-cholesterol <40 mg / dl in men and < 50 mg / dl in women. - beyond the level of LDL-C, a treatment for all those subjects with a triglyceride level > 200 mg / dl (15) is recommended.
The guidelines on the prevention of cardiovascular diseases of the European Society of Cardiology (ESC) recommend
- in patients with a manifest ATS a target level of LDL-C < 100 mg% - in those patients with multifocal ATS with previous CAD, PAD and diabetes or multiple risk factor : a desirable target of 80 mg% s (16).
The Recommendation n. 2 of the TASC II document on the control of lipids patients with PAD suggests that patients with PAD and an LDL-C > 125 mg/dl, because of the risk of having another concomitant location of atherosclerosis and a risk of mortality like the patients with known ischemic heart disease, should do
- secondary prevention, in first instance - diet changes lifestyle followed by - administration of statins in order to reduce LDL-C <100 mg% in both asymptomatic or symptomatic patients and < 70 mg in patients with previous AMI or diabetes or multiple RF because considered at very high risk (1)
Despite the fact that several studies have shown that patients with PAD present a high risk of cardiovascular mortality, the disease still receives little attention. In fact, the correction of cardiovascular risk factors and secondary prevention measures are implemented effectively and less widespread than currently ago against ischemic heart disease, as shown by the data of the PARTNERS study (2).
The study demonstrated the lack of awareness of the disease both in patients and in medical care physicians. 83% of subjects diagnosed with PAD were aware of their condition and only 49% of their doctors were aware of the diagnosis of PAD. Moreover, in patients with PAD, the major cardiovascular risk factors were corrected less effectively compared with ischemic heart: high blood pressure was treated in 88% vs 95%, dyslipidemia in 56% vs. 73% and platelet antiplatelet therapy was prescribed in 54 % vs 71% of cases. This study shows that PAD is underestimated by the physician in general medicine can be a barrier to effective prevention of cardiovascular complications (2).
PAD is independently associated with an increase in the rate of mortality; it is not a rare clinical condition and simple questionnaires are able to facilitate its identification (WHO/or Questionnaire of Rose-Edinburgh), although probably the most sensitive test remains ABI (2, 3).
The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.
PAD should be properly included in the assessment of cardiovascular risk and in screening program of patients at risk. Patients with PAD actually represent a very high-risk category of fatal and non-fatal cerebrovascular and cardiovascular events. Novo S, Pitruzzella V, Novo GChair of Cardiovascular Disease, post-graduate School of Cardiology, Master of Vascular Diseases, Center for the Diagnosis of Preclinical Atherosclerosis and Secondary Prevention, Division of Cardiology, University Hospital “P. Giaccone” of the University of Palermo, Italy
1) Inter-Society Consensus for the Management of Peripheral Arterial Disease TASC II. Norgren L, Hiatt WR, Dormandy JA, Nehler MR, Harris KA, Fowkes FG and TASC II Working Group; Bell K, Caporusso J, Durand-Zaleski I, Komori K, Lammer J, Liapis C, Novo S, Razavi M, Robbs J, Schaper N, Shigematsu H, Sapoval M, White C, White J. Int Angiol 2007; 26: 81-157
2) PARTNERS Study - Peripheral Arterial Disease Detection, Awareness, and Treatment in Primary Care. Hirsh AT, Hiatt WR et al., JAMA 2001; 286: 1317-24
3) Association of low ankle brachial index with high mortality in primary care.Diehm C, Lange S, Darius H, Pittrow D, von Stritzky B, Tepohl G, Haberl RL, Allenberg JR, Dasch B, Trampisch HJ. Eur Heart J. 2006; 27:1743-9
4) Feringa HH, van Waning VH, Bax JJ, Elhendy A, Boersma E, Schouten O, Galal W, Vidakovic RV, Tangelder MJ, Poldermans D. Cardioprotective medication is associated with improved survival in patients with peripheral arterial disease. J Am Coll Cardiol 2006; 47: 1182-7
5) Ridker PM, Rifai N, Pfeffer MA et al. Inflammation, Pravastatin, and the risk of coronary events after myocardial infarction in patients with average cholesterol levels. Cholesterol and Recurrent Events (CARE) Investigators. Circulation 1998; 98: 839–44.
6) Wierzbicki A. S., Poston R, Ferro A. The lipid and non-lipid effects of statins. Pharmacology & Therapeutics. 2003; 99: 95–112.
7) Pedersen TR, Kjekshus J, Pyorala K, Olsson AG, Cook TJ, Musliner TA, et al. Effect of simvastatin on ischemic signs and symptoms in the Scandinavian Simvastatin Survival Study (4S). Am J Cardiol 1998; 81: 333-6.
8) Novo S, Strano A. Lipid lowering drugs in the treatment of peripheral arterial disease of the lower limbs: results of the SISOPAD (Simvastatin Italian Study on Peripheral Arterial Disease). Proceedings of the 7th Annual Meeting of the Mediterranean League of Angiology and Vascular Surgery, March 22-25 1996, Limassol, Cyprus, N.S. Angelides Ed. Ariston Philis Printers. 1996; p. 73-4.
9) Mondillo S, Ballo P, Barbati R, Guerrini F, Ammaturo T, Agricola E et al. Effects of simvastatin on walking performance and symptoms of intermittent claudication in hypercholesterolemic patient with peripheral vascular disease. Am J Med 2003;114; 359-64.
10) Aronow WS, Nayak D,Woodworth S, Ahn C. Effect of simvastatin versus placebo on treadmill exercise time until the onset of intermittent claudication in older patients with peripheral arterial disease at six months and at one year after treatment. Am J Cardiol 2003; 92: 711-2.
11) Statin use and functional decline in patients with and without peripheral arterial disease.Giri J, McDermott MM, Greenland P, Guralnik JM, Criqui MH, Liu K, Ferrucci L, Green D, Schneider JR, Tian L. J Am Coll Cardiol 2006; 47: 998-1004
12) Heart Protection Study (HPS) Collaborative Study. Randomized trial of the effects of cholesterol-lowering with simvastatin on peripheral vascular and other major vascular outcomes in 20,536 people with peripheral arterial diseases and other high risk patients. J Vasc Surg 2007; 45: 645-54.
13) Schillinger M, Exner M, Mlekusch W et al. Statin therapy improves cardiovascular outcome of patients with peripheral artery disease. Eur Heart J. 2004; 25: 742–748.
14) Aronow WS, Ahn C. Frequency of new coronary events in older persons with PAD and serum LDL-C >125 mg/dl treated with statins versus no lipid-lowering drug. Am J Cardiol 2002; 90: 789-79.
15) Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III guidelines.Grundy SM, Cleeman JI, Merz CN, Brewer HB Jr, Clark LT, Hunninghake DB, Pasternak RC, Smith SC Jr, Stone NJ; National Heart, Lung, and Blood Institute; American College of Cardiology Foundation; American Heart Association. Circulation. 2004; 110: 227-39. Review.
16) European guidelines on cardiovascular disease prevention in clinical practice: executive summary. Fourth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (Constituted by representatives of nine societies and by invited experts), Graham I, Atar D, Borch-Johnsen K, Boysen G, Burell G, Cifkova R, Dallongeville J, De Backer G, Ebrahim S, Gjelsvik B, Herrmann-Lingen C, Hoes A, Humphries S, Knapton M, Perk J, Priori SG, Pyorala K, Reiner Z, Ruilope L, Sans-Menendez S, Scholte op Reimer W, Weissberg P, Wood D, Yarnell J, Zamorano JL; Other experts who contributed to parts of the guidelines:, Walma E, Fitzgerald T, Cooney MT, Dudina A; European Society of Cardiology (ESC) Committee for Practice Guidelines (CPG), Vahanian A, Camm J, De Caterina R, Dean V, Dickstein K, Funck-Brentano C, Filippatos G, Hellemans I, Kristensen SD, McGregor K, Sechtem U, Silber S, Tendera M, Widimsky P, Zamorano JL, Hellemans I, Altiner A, Bonora E, Durrington PN, Fagard R, Giampaoli S, Hemingway H, Hakansson J, Kjeldsen SE, Larsen ML, Mancia G, Manolis AJ, Orth-Gomer K, Pedersen T, Rayner M, Ryden L, Sammut M, Schneiderman N, Stalenhoef AF, Tokgözoglu L, Wiklund O, Zampelas A. Eur Heart J 2007; 28: 2375-414
17) Impact of ramipril in patients with evidence of clinical or subclinical peripheral arterial disease.Ostergren J, Sleight P, Dagenais G, Danisa K, Bosch J, Qilong Y, Yusuf S; HOPE study investigators. Eur Heart J 2004; 25, 17-24
Vol 6 N°32
Prof. Novo S, Prof V. Pitruzella, Prof. G. Novo
Chair of Cardiovascular Disease, post-graduate School of Cardiology, Master of Vascular Diseases, Center for the Diagnosis of Preclinical Atherosclerosis and Secondary Prevention, Division of Cardiology, University Hospital “P. Giaccone” of the University of Palermo, Italy.
*Nucleus member of the working group on peripheral circulation
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