The effects of risk factors on Ankle-Brachial Index (ABI)

Cardio-vascular Diseases (CVDs) have many shared risk factors that are based primarily on the main mechanism of a specific disease’s pathophysiology. Atherosclerosis is one such mechanism which is quite prominent as it underpins, amongst others, Coronary Heart Disease (CAD), the leading cause of mortality worldwide, and Peripheral Arterial Disease (PAD).

Atherosclerosis, like PAD itself, is often and for a considerable amount of time asymptomatic and only becomes apparent when it’s already at an advanced stage and the affected person has a cardiac event or a stroke. There are diagnostic methods that can reliably and accurately ascertain the presence of atherosclerosis, but these are rarely used for the large-scale screening of potential patients due to their complexity or prohibitive cost. Still, there are ways to evaluate a patient’s state of cardiovascular health on the basis of the presence and severity of CVDs that are not immediately fatal. This applies specifically to PAD, as its presence has been recognised as an important predictor of overall cardiovascular health and the related risk of premature mortality [1].

Who is at risk for Peripheral Arterial Disease (PAD)?

The risk factors for PAD are similar to those for atherosclerosis, with the most prominent being smoking as the biggest risk factor for PAD. At the same time it is a major preventable cause of PAD and other diseases, especially CVDs. Smoking rates are fortunately declining or have levelled off, but only in the developed world: the situation is exactly the opposite in the developing world. The best prevention would of course be total abstinence, but timely cessation of smoking also has many benefits and greatly (but gradually) decreases the negative effects of many smoking-related diseases [2, 3, 4, 5, 6]. At the same time it should be noted that this effect is not as pronounced when it comes to PAD as even former smokers are at an increased risk long after they stop smoking [7].

Diabetes is another important risk factor for PAD, not only because of its overall negative effect on CVD-related mortality, but because of the possibility of mistaking the symptoms of PAD for the side effects of diabetes (by either the patient and clinician) [8]. The association between diabetes and intermittent claudication (most typical outward symptom of PAD) remains particularly strong. It is 3.5 times more prevalent in diabetic males and 8.6 times more prevalent in diabetic females (in comparison with the non-diabetic populations for each gender) [9].

There are other important (modifiable and non-modifiable) risk factors besides diabetes, such as age and family history. PAD is uncommon in younger individuals, but risk rises considerably with age – studies have shown that the risk of PAD increases approximately two to three times for every 10-year increase in age after the age of 40 [10]. Risk is also higher in individuals with a family history of PAD with studies indicating a two-fold increase in risk for those with a family history of the disease in comparison with those without [11]. Lastly, weight is an important risk factor as both under and overweight individuals are at an increased risk of PAD [12, 13].

Patients that fall in these categories should be examined for possible PAD on the basis of an ABI (Ankle-brachial Index) measurement, which is the fastest and most convenient method for screening large numbers of potential patients.

Ankle-Brachial Index (ABI) measurement, simple solution for diagnosis PAD.