Is peripheral artery disease uncommon in women?

Background

It is surprising how much peripheral artery disease (PAD) has been neglected by physicians over the years, even by cardiologists; the concept that arteries located remotely from the heart could play an important role in hemodynamics and physiopathology did not attract very much their attention. Intermittent claudication, the typical manifestation of PAD, was considered to be a rather innocent symptom that only affects quality of life without causing any other problems. However, we have been overwhelmed by several convincing data published in the last decade, that PAD is largely caused by atherosclerosis and that, as such, could be seen as a marker of atherosclerosis. Consequently, as atherosclerosis elsewhere in the body, it can lead to strongly increased morbidity and mortality (2). In the REACH study (3), it was clearly seen that the cumulative end point of death, myocardial infarction and hospitalisation is surprisingly higher in PAD patients than in coronary patients. In women, the situation often gets worse as physicians do not expect to find PAD in them and thus, often fail to recognise the condition. Such lack of recognition explains, at least partly, why women receive poorer management and, as a consequence, are less protected against the life threatening complications of atherosclerosis (4).
Indeed, physicians believe that PAD in general is rare in female patients and epidemiology informs us that the prevalence of PAD is lower in women under 50 years of age than in men, although it is, by far, not negligible. However, between 50 and 70 years of age, prevalence severely increases and is at least as high, if not higher, in women than in men. This is automatically accompanied by increased morbidity and mortality; moreover, such bad prognosis is further accentuated by the fact that even for the same disease state, event rates may be higher for women, especially when the ankle brachial index (ABI) is low. All these findings, including those in the recent scientific statement from the American Heart Association describing the epidemiological burden of PAD in women (1), clarify that prognosis of PAD in women, especially at a higher age, is not good and that PAD should be detected as soon as possible to get adequate protective treatment. 

Clinical aspects

It is generally accepted that intermittent claudication is the most typical symptom; still, it has become clear from several recent papers (4) that many PAD patients do not get intermittent claudication but rather present with atypical symptoms or even no symptoms; again, this also is the case in women. Some studies suggest that atypical symptoms or signs are even more common in women than in men and are accompanied by greater functional impairment. Thus, there is a need to identify women with PAD in order to prevent systemic complications of atherosclerosis (for example at the coronary and cerebral circulation level) and local complications that lead to loss of functional capacity and risk of amputation. This again points to the importance of a good clinical examination including palpation of all arteries in the limbs and auscultation of bruits in the area of the femoral artery. The concept still is that a clearly decreased pulse amplitude associated to a sharp bruit, points toward a clinically significant stenosis (70% or more). This approach is easy for physicians with some training in this domain and does not elicit any particular costs. 

Management 

The value of clinical examination can be further improved by measurement of the ankle-brachial index (ABI ) which should be done in all patients suspected of having peripheral artery disease (table 1).  This easy, noninvasive and cheap technique yields excellent results: sensitivity is 79% and specificity 96%; a value of 0.90 or lower has a positive predictive value of 95% or more; a value of 1.10 or more has a negative predictive value of 99%  (4), which is a remarkable figure knowing how easy the technique is! (2) The only problem is hardening of the arterial wall, that especially when calcified, can lead to incompressibility of the artery and cause erroneous readings; this often is the case in diabetic patients. The only solution in that condition is measuring the toe pressure, most often using photoplethysmography. Walking distance can best be quantified by exercising on the treadmill;  however, the test can be negative when there are no symptoms which, as indicated above, often is the case in men as in women. Symptoms of walking incapacity can be treated with drugs such as cilostazol (not available in several European countries) and naftidrofuryl; however, better results are obtained by exercise programs, preferably supervised with regular assessments on the treadmill. Another very helpful piece of advice to patients is to stop smoking, which is particularly important in women as almost all women with PAD are heavy smokers. There are no arguments for a gender difference in respect to efficacy of treatment; still, in line with the lower care observed in female patients, the majority of patients following exercise therapy are men; women seem to follow exercise programs much less. As for more severe PAD, interventional treatment is necessary. Antiplatelet drugs (aspirine, clopidogrel) are, of course, indicated for all. One should not forget that the underlying disease is atherosclerosis and that all other risk factors such as hypertension (2), should be controlled with the greatest care. 

Awareness 

Whereas, accurate PAD-specific health information for women especially would likely improve both their own health and that of society at large through their role as coordinator of care within the family, awareness of PAD both in women and men is remarkably low compared to knowledge of other cardiovascular diseases. Furthermore, signs and symptoms of PAD continue to be ignored and ABI is by far, not measured often enough. Peripheral artery disease, as a very strong risk factor for cardiovascular disease is poorly controlled; the authors of several recent reviews (1-4) insist that nationwide programs should be organised to inform the population of PAD and its complications. Especially for women all physicians  (GPs, internists, cardiologists, gynecologists) seeing patients above 50 years should be aware of the problem and set the first step to detect the disease. 
Table 1. Recommendations for measuring the ankle-brachial index (5)

ABI should be measured in:

All patients who have exertional leg symptoms
All patients between the ages of 50-69 and have a cardiovascular risk factor (in particular diabetes or smoking)
All patients older than 70 years regardless of risk factor status
All patients with a risk score between 10 and 20%

Conclusion

Peripheral artery disease is one of the most neglected areas in cardiovascular medicine. However, its prevalence is high and this is the case in both in men and women. Moreover, answering the question posed in the title of this paper, prevalence of PAD is similar or even higher in women than in men after age 50. The magnitude of the problem is amplified by the fact that symptoms are often absent or atypical. All physicians, and especially primary care providers and gynecologists, should identify women with PAD, or those at risk of PAD and should perform a good clinical examination focused at PAD and measure the ankle brachial index. Risk factors should be carefully examined and controlled. Authorities should be informed of the risk of PAD in general, but especially in women, to help establish programs to detect the disease and inform the population of means for prevention and treatment.