The Need for Improved Identification and Treatment of Peripheral Arterial Disease

As implied by the term, peripheral artery disease (PAD) has long been relinquished to the margins of cardiovascular medicine. All too often, the focus of healthcare providers has been concentrated towards diagnoses associated with supposed higher urgency such as acute coronary syndromes. However, the implications of PAD on mortality and quality of life are no less concerning than coronary or cerebrovascular disease. Moreover, PAD exacts a substantial monetary toll on our health care budget and a debilitating cost in our patient’s lives. From an economic standpoint, annualized cost of inpatient therapy for PAD has been estimated at $6.31 billion without consideration of indirect costs associated with productivity, absenteeism, and activity impairment.^1,2 Additional costs of outpatient diagnosis and treatment likely further underestimate the true economic burden. Yet, the most compelling cost of PAD is the impact on our patient’s lives.

The current Scientific Statement from the American Heart Association calls to attention the underappreciated prevalence and clinical relevance of PAD throughout the world. This statement provides a thorough foundation evaluating the current burden and trends related to PAD along with diagnostic modalities and their utility in guiding therapy. Notably, it brings to light the underutilization of evidence-based treatment with respect to risk factor modification and symptom palliation as well as revascularization among patients suffering from PAD. It also serves as a reminder to the medical community that improved diagnosis and appropriate treatment of PAD is needed to save both lives and limbs.

Under recognition of PAD remains the foundational limitation to improving patient care. We feel it is important to properly define PAD as all disorders attributable to a primary vascular pathology anywhere in the body. Disease processes including atherosclerosis, vasculitis, and thrombosis fall under the purview of PAD, and as a result, experts in this field must familiarize themselves with the plethora of alternative presentations and pathologies that ultimately affect our patients. Although the current statement focuses on lower extremity PAD defined as arterial atherosclerotic disease affecting the aortoiliac segment and below, it is important to remember that vascular specialists must be facile with the entire spectrum of vascular medicine in order to deliver optimal care.

PAD symptoms are frequently overlooked or misappropriated to conditions of normal aging such as arthritis. In fact, patients present with a diverse array of symptoms from classical calf cramping to paresthesia to simply increased fatigue. Perhaps the majority of patients lack any of these symptoms and manifest subtle changes in daily activities making PAD very difficult to discern from other disease states. The first point of medical contact for the majority of patients with PAD occurs in the clinics of primary care practitioners (PCP) who have the greatest potential for improving our shortcoming in identifying PAD. Screening starts at the bedside with the history and physical examination. Patients should be evaluated for “below the waist” symptoms paying particular attention to subtle changes in strength, sensation, and endurance due the varying clinical presentation of PAD. The exam must incorporate evaluation of a patient’s entire vascular circulation, especially, the lower extremity, most importantly the feet. Bare of shoes and socks, the feet offer insight into the underlying disease process and should prompt practitioners to perform additional investigations when necessary.

The current screening recommendations for PAD vary among expert organizations and the US Preventative Services Task Force. This AHA statement supports PAD screening in symptomatic patients and high-risk patient without symptoms. However, the use of further liberalized screening protocols amongst elderly patients may be beneficial. The Viborg Vascular trial showed that whole population screening among males aged 65-74 years for abdominal aortic aneurysm, peripheral arterial disease, and hypertension resulted in improved mortality over a 5-year period. Notably, optimization of medical therapy with anti-hypertensive and lipid lowering agents was the most frequent intervention in this trial suggesting a real-world benefit to medical therapy.³ Moreover, the screening was also cost effective.⁴ The ankle brachial index (ABI) is the first line modality for PAD screening and is only reimbursable in the setting of symptomatic PAD. As a result, patients with atypical or absent symptoms do not undergo ABI evaluation and practitioners are frequently discouraged from pursuing additional PAD screening despite data suggesting potential benefit. This must change in order to improve our screening deficit and increase recognition of a treatable disease with significant morbidity and mortality. We advocate for a change in reimbursement policies in order to increase screening and facilitate a change in national practice patterns.

There is a disproportionate prevalence of PAD among vulnerable populations with disparities in relation to income, sex, and race. Data from the National Health and Nutrition Examination Survey revealed that individuals in the lowest income group had a two-fold increased odds of PAD when compared to those in the highest income group. Likewise, other studies have shown that lower education levels, female sex, and African-American race are all associated with increased prevalence of PAD. The unequal burden of disease amongst these susceptible populations poses a moral obligation to the medical community. These disparities offer a unique chance for targeted screening to improve current medical inequities, preventative measures, and gaps in vascular care.

The pathology of PAD spans a spectrum with the potential to affect any arterial vascular bed in the body producing illnesses ranging from vascular dementia to diabetic foot ulcers. Understanding the relevance of PAD as a whole-body disease process that extends beyond limb claudication is important for appreciating its significance and tailoring therapy. Current AHA/ACC PAD guidelines strongly support strategies including smoking cessation, blood pressure and diabetes management, lipid optimization, and anti-platelet therapy. However, the use of these therapies is dismally low in real world practice. The current medical infrastructure incentivizes procedures and interventions over medical optimization and prevention.⁵ Recognizing the value of preventative medicine from a systems level is necessary to improve the chasm between guideline recommendations and clinical reality.

Optimizing medical management and mitigation of risk factors serve as therapeutic foundations in PAD. Supplemental treatment options can best be evaluated by categorizing PAD into macrovascular and microvascular disease. Macrovascular disease refers to PAD that is amenable to surgical or endovascular intervention while microvascular disease refers to network of small arteriolar beds (~100 um in diameter) throughout the body. Traditional symptoms of claudication and chronic limb ischemia can be treated with either surgical or endovascular modalities. Currently, no clear evidence has supported the superiority of one of these therapies over the other. There is a growing amount of criticism regarding the limited number of randomized clinical trials (RCTs) comparing endovascular therapies to surgery that have largely been underpowered as well as sub-optimally designed and executed. We must raise the quality of future RCTs to better understand the optimal circumstance for either macrovascular therapy. Furthermore, the field of endovascular options has grown to include multiple treatment strategies including balloon angioplasty, stenting, atherectomy, and drug delivery systems. With a host of potential options, we need better RCTs to delineate the best treatment option based on lesion location and patient characteristics. On the opposite end of the spectrum, there are currently no proven therapies for microvascular PAD despite microvascular disease being associated with PAD progression and complications.⁶ The dearth of treatment options highlights the desperate need for additional research focusing on potential therapies that embrace contemporary pharmacotherapy and molecular techniques.

The treatment of PAD patients is distributed among multiple stake holders including vascular surgeons, interventional cardiologists, interventional radiologists, general cardiologists, primary care practitioners, podiatrists, wound care specialists, medical subspecialists such as endocrinologists, nephrologists and infectious disease specialists, physical and occupational therapists, nurses, and other medical personnel who are all integral components of optimizing patient care. Currently, the majority of PAD care is provided under isolated surgical or medical practices. The use of a multidisciplinary team-based approach to treating PAD is an innovative concept that has been limited to a few centers throughout the country. This is likely related to traditional separation amongst surgical and medical specialties in regard to institutional referral and practice patterns along with competition for patient populations. Despite these limitations, we believe there is tremendous value in combining the insight of multiple specialties in the care of PAD. The tribalism in the past of single specialty hegemony over the field is anachronistic at best and injurious to patients at worst.

As this scientific statement highlights, PAD patients are often complex with variable clinical presentations and disease severity that are at high risk for a deteriorating clinical course and increased mortality. This underscores the need for additional perspectives to optimize standards of care. Models incorporating multispecialty collaboration in treating cardiovascular diseases have shown success in the areas of heart failure, cardiogenic shock, and structural cardiology resulting in guideline and societal support.^7-9 We believe that PAD is other clinical problem that a multidisciplinary approach has the potential to improve. A collaborative environment between surgical and medical practitioners may help tailor treatment modalities to optimize individual patient care.¹⁰ Furthermore, a close working relationship between surgeons and interventionalists lays the foundation for innovative care and a holistic evaluation that considers the strengths and weaknesses of all therapeutic options. Lastly, a team-based approach brings immensely valuable treatment from social work, occupational therapy, and physical therapy to the forefront and facilitates awareness, access, and treatment for our patients. Combining the expertise, experience, and therapeutic options through the implementation of multi-disciplinary team-based evaluation for PAD has the potential to make a deep and lasting impact in the care of PAD.

The American Heart Association Scientific Statement on Peripheral Arterial Disease is a valuable tool for all medical practitioners treating patients at risk for PAD. The statement offers an in-depth update on PAD and aims to help healthcare professionals improve the current trend in under-recognition and under-treatment. Improving awareness of PAD and education regarding diagnosis and therapy is the initial step towards improving care. Furthermore, the utilization of multi-disciplinary teams for managing PAD may offer additional benefit in improving current shortcomings. This statement provides a tool to overcome current limitations by providing an up-to-date educational reference for all medical professionals to further develop their understanding of PAD and in doing so makes a meaningful step toward improving recognition and treatment of those suffering from PAD.