Cardiovascular medicine has always been focused on estimation of the risk of developing life-threatening complications. Remarkably, in this connection, peripheral vascular disease has largely been forgotten or underestimated. Peripheral venous disease frequently results in being more appealing because it causes more symptoms and has more visible aspects (for example skin changes). By contrast, the arterial part of the circulation in the limbs has been forgotten for many years; this is surprising in view of the fact that diagnosis of peripheral arterial disease (PAD) in many cases is rather easy on the basis of simple clinical tools and non-invasive technology.
Why did PAD escape the attention of physicians?
There are a number of reasons which may explain this lack of interest: many patients with PAD have no or atypical symptoms or signs; as a consequence, the clinician’s attention was not focused on detecting arterial disease, and thus the risk linked to PAD was underestimated. The first twenty years of the present millennium have seen fundamental changes in this respect. We shall highlight a number of these old and new aspects in several articles in the e-journal in the coming weeks and months. We shall focus essentially on arterial disease in the lower extremities (LEAD) at the chronic phase of its evolution.
Examples of topics to come are: the risk of coronary and cerebral accidents in patients with PAD, the means of preventing such accidents by early diagnosis and preventing thrombus formation in the limbs and elsewhere in the body, the surprisingly positive effects of physical training on symptoms, the new means for interventional treatment such as balloon/stenting and clot-removing techniques; all of this without forgetting the accent on early diagnosis that can arise from simple clinical examination in every cardiac patient with the aid, if necessary, of simple non-invasive tests. Moreover, other components of the vascular system have proven their important role, e.g., the retinal circulation, and the cutaneous circulation in the fingers and toes.
What is the prevalence of PAD in the population?
PAD is by no means an infrequent clinical condition. According to the old Rose questionnaire, the prevalence in men below 50 years of age is 1.5%, between 50 and 70 it increases to 5-10% and over 70 it reaches up to 70% . New clinical population studies should be carried out in this respect, but the prevalence can be expected to be higher using current clinical tools .
Physicians often postulated that PAD is the unpleasant prerogative of men at older age; however, reality has taught us that it is certainly also seen in female patients, albeit at a lower prevalence below the age of 70 years, but at almost the same prevalence above that age . Also, at the higher age, the clinical presentation in women is not only atypical but often more severe.
Causes and risk of PAD
Atherosclerosis is by far the main cause of PAD. It is also an important marker for the presence of atherosclerosis in general. Indeed, symptoms could come from peripheral ischaemia but often they are the result of atherosclerosis elsewhere in the body, such as in the coronary or cerebral territories. This has given PAD a quite different clinical importance as, besides symptoms coming from local ischaemia, the whole picture in many patients is dominated by events in the coronary and/or cerebral areas. Finding PAD should compel the clinician to investigate the coronary and cerebral arteries. This was the main message of the CoCaLIS document presented for the first time at the world meeting of the International Union of Angiology .
As for any atherosclerotic disease, risk factors play a dominant role both as causes of the disease and as targets in its management. As a rule, an increase of all major risk factors is present in PAD patients. Already mentioned above is the relationship between age, gender and PAD. Hypertension, especially systolic hypertension, is associated with a twofold to threefold increase in the risk of intermittent claudication . Diabetes mellitus is highly prevalent in PAD, especially in the more advanced cases presenting with cutaneous ischaemia. Smoking and hyperlipidaemia are highly prevalent; clinicians are well aware that there is a clear relationship between the level of nicotine abuse and the severity of intermittent claudication. Regularly novel risk factors have been described and the role of inflammatory parameters is clearly increasing .
Control of risk factors plays a dominant role in the medical management of PAD patients; such treatment is not essentially different to the control of any other atherosclerotic disease. Unfortunately, this area of treatment is very often neglected in many PAD patients. This message needs to be underlined as an essential first step in the management of PAD patients .
Diagnosis of PAD in the lower extremities (LEAD)
In the forthcoming papers in the e-journal, the value of the many currently available tools to diagnose LEAD will be discussed in detail. Even with the many technical tools and innovations developed in recent years, clinical examination is, as previously mentioned, very informative as a first step in diagnosis. Careful palpation of arterial pulses and auscultation of arterial bruits can be the first means of detecting the presence of LEAD and in the evaluation of the severity of arterial stenosis or occlusion. The teaching and training of medical students should be focused more towards this aspect in order to get a better level of expertise in this area. Clinical examination can be strengthened significantly by measuring ankle brachial index (ABI). Again, this will be further explained in one of the upcoming papers. It is worth mentioning that there is a significant relationship between the ABI index and the cardiovascular event rate.
Clinical classification of PAD in the lower extremities (LEAD)
There are two major classifications of LEAD: the older one, developed by Fontaine a number of years ago, is still used routinely in Europe; in the USA a more detailed and recent classification was described by Rutherford .
Stage I comprises all patients with no or atypical symptoms. In most parts of the world this is the largest group.
Stage II represents patients with intermittent claudication. Fontaine divides this group into “non-disabling” claudication (class IIa) and disabling claudication (class IIb); Rutherford divides this group into three groups, namely “mild, moderate and severe claudication”.
Stage III indicates patients with ischaemic rest pain.
Stage IV indicates patients with ulceration or gangrene. In the Rutherford classification this class is subdivided into patients with minor tissue loss and those with major loss. These patients regularly experience the consequences of highly pronounced ischaemia at the distal parts of the extremities which is frequently associated with diabetes.
It should be mentioned that symptoms can vary considerably from patient to patient. In addition, in every patient there can be substantial variation in symptoms from day to day, and during and after treatment. Many other factors such as the patient’s general condition, blood pressure level, and nicotine abuse interfere significantly in the clinical presentation.
Conclusions and take-home messages
Patients with peripheral arterial disease (PAD), especially when localised in the lower extremities (LEAD), have a total cardiovascular risk that is largely not detected and underestimated. In many patients, even though the risk is present, symptoms are atypical or even absent. In all cardiac patients therefore, for early detection of PAD, pulses in lower extremities should be palpated as a matter of routine.
Measuring ankle brachial pressure index is very helpful both for diagnosis and for follow-up.
In all patients, whatever the clinical presentation, careful sustained attention should be given to correcting the elevated total cardiovascular risk.