Peripheral arterial disease (PAD, increasingly also referred to as lower extremity artery disease or LEAD) is considerably less well-known among the public than other cardiovascular diseases (CVDs) that are more often depicted in popular culture, like coronary artery disease (CAD) and stroke. However, PAD’s connection to overall cardiovascular health and a myriad of serious complications caused by it are worthy of attention from both laymen and professionals, although even the latter are often less educated about the most critical aspects of the disease than they should be.
In this blog you will learn:
- Knowledge (or the lack of thereof).
- Accurate & reliable screening & diagnosis.
- The diabetes-PAD connection.
- Treatment of PAD.
- The future of PAD diagnosis & treatment.
What does the general (and professional) public know about PAD?
Even though worldwide prevalence of PAD was estimated to be 236.62 million in individuals over 25 years of age in 2015 and is projected to rise, the general population—even those in risk groups—is largely oblivious, as demonstrated by numerous studies . A cross-sectional, population-based telephone survey encompassing 501 adults ≥50 years of age conducted in Canada found that despite many of them having hypertension (43%), hyperlipidaemia (37%), diabetes (12%) and a history of smoking—nearly half of them smoked at some point in their lives, (all known cardiovascular risk factors), only 36% knew anything about PAD .
A similar study, albeit carried out as face-to-face interviews, was conducted in Ireland among 336 individuals over the age of 40: 98% knew about diabetes, 94% about stroke and 78% about CAD, but only 19% knew about PAD. Those most likely to know had higher (formal) education than those who did not . Education as a factor was also highlighted in a comparable US study .
By virtue of their extensive schooling and training, general practitioners (GPs) are generally well-educated about the natural history of PAD and screening and diagnosis (to a certain extent), yet still likely to misdiagnose potential patients with PAD. In many of those cases, knowledge was less of an issue, in contrast to lack of time (as allocated to each patient) and proper equipment for screening . Quite a few of them also (too) extensively use unreliable screening/diagnostic methods .
How is PAD diagnosed?
There are several established methods for diagnosing PAD with highly variable accuracy, reliability, and cost. The most used are screening based on medical history and physical examination (pulse palpation). However, both fall short either due to an absence of intermittent claudication (the presence/absence of risk factors is an unreliable sign) or the need for extensive training and practical experience to perform them reliably (examination) [6, 7].
Regarding intermittent claudication: only 10% of all patients with PAD have this symptom, 40% are entirely asymptomatic, and the remaining 50% have atypical symptoms that could be attributed to other conditions [8, 9]. Reliable diagnosis can, therefore, be made only by a method not subject to the presence of symptoms or user (in)experience—like an ABI assessment, which is the recommended screening method for use in general practice. The method, or rather the equipment used to perform it, should also be at the disposal of many other healthcare facilities, like those that cater to diabetic patients.
Are diabetics more at risk for PAD?
Together with tobacco smoking, diabetes mellitus (type 1 and 2) is the most prominent risk factor for PAD and associated with significantly worse morbidity and a higher risk of adverse outcomes. It is a significant risk factor for virtually all CVDs as it doubles the risk for any of them in those with diabetes and is associated with greatly increased (cardiovascular) mortality [10, 11]. When it comes to PAD, it is estimated that 20% to 30% of patients with the disease also have diabetes, but this is generally regarded as an underestimation since it postulates only symptomatic disease, grossly neglecting to consider the common asymptomatic manifestation .
Symptomatic PAD (intermittent claudication) as such is 3.5 times more prevalent in diabetic males and 8.6 times more prevalent in females than in non-diabetics of each respective gender . However, there are far worse complications like critical limb ischaemia (CLI). As many as 50% (some estimates go as high as 76%) of patients with CLI also have diabetes, and on average they suffer higher rates and more severe outcomes (lower-extremity amputation, mortality) than non-diabetic patients [14, 15, 16]. Those individuals are prime candidates for revascularisation or other more drastic procedures.
How is PAD treated?
Mild and moderately severe PAD is generally conservative and entails lifestyle modification (reduction of risk factors such as smoking, unhealthy eating, bodyweight with an increase in physical activity, and diligent control of hyperglycaemia) in conjunction with medications for the management of hyperlipidaemia and hypertension [17-23]. More severe cases, when limb viability is threatened, require surgical and endovascular treatment. Bypass surgery is or was the most well-known surgical procedure since there are now newer, less risky alternatives .
What are the new methods of diagnosis and treatment of PAD?
Thanks to advancements in minimally invasive treatment, even patients with the most severe forms of PAD (CLI) have a better chance of saving their limb than ever before. In many cases (if there are not any contraindications), bypass surgery is substituted with angioplasty with stent placement or even an atherectomy . The latter procedure is especially suitable for the treatment of PAD in the infrainguinal space .
Cost-effective and convenient tools for ABI assessment are one of the results of the technological advance that touched PAD. Conventionally, ABI is usually measured using a sphygmomanometer and a Doppler probe (wand), but while accurate and reliable, this approach requires a fair amount of training and experience to mitigate user error and may take up to 30 minutes [27, 28]. A better alternative is an oscillometric-plethysmographic device, which can perform the measurement in a mere one minute, is user-error free, and requires minimal training, making it particularly suitable for use in general practice—the first line of defence against PAD [29, 30].
Healthcare decision-makers should be aware of the dangers of PAD, its association with overall cardiovascular health, and the high associated costs of treatment, particularly when in advanced stages of the disease. Mandatory preventive screening of older patients, even if they are not showing symptoms, is therefore recommended as a crucial tool for timely diagnosis and treatment.