Peripheral arterial disease (PAD) is a burdensome condition that affects 10% of the
population and increases to 15-20% among those ≥70 years. In PAD, the underlying
pathophysiologic process, atherosclerosis, presents itself as blockages in patients' leg
arteries that prevent adequate blood flow and can result in burning calf (or buttock)
pain while walking and that is relieved upon rest ('intermittent claudication'). In
extreme cases, PAD can progress to critical limb ischemia, characterized by ulceration,
gangrene, and threatened limb viability. Patients with PAD have significant
atherosclerotic risk factors and impaired health status - thus creating 2 therapeutic
goals, prevention of cardiovascular events and improved symptom control and quality of
life. While the onset of PAD tends not to be as abrupt as for other cardiovascular
conditions, such as stroke or myocardial infarction, leg symptoms can severely affect
patients' health status (their symptoms, functional status, and quality of life). In
addition, patients' risk of having a cardiovascular event is disproportionately high, as
compared with other cardiovascular diseases. One-year cardiovascular event rates -
including cardiovascular death, myocardial infarction, or stroke, or other
hospitalizations for atherothrombotic events - are estimated to be over 21% in patients
with PAD, as compared with 15% for coronary artery disease and stroke.9 Mortality rates
are 15-30% 5 years after diagnosis. Part of these disproportionate event rates may be
explained by under recognition and under treatment of PAD and its underlying
atherosclerotic process. Finally, PAD not only impacts patients' individual lives and
their families; it also has a tremendous impact on society at large. It is estimated that
annual costs associated with vascular-related hospitalizations in PAD patients in the US
exceeds $21 billion.
The primary treatment goals for PAD are symptom relief, quality of life improvement, and
cardiovascular risk reduction. Several treatment options are available for PAD, ranging
from invasive revascularization procedures, including peripheral percutaneous
intervention (PPI) and surgical revascularization to non-invasive options, including
supervised and home-based exercise therapy, PAD-specific medications, and cardiovascular
risk management. While there is no "gold-standard" treatment for PAD, less invasive
options are recommended as a first-choice treatment. Despite these recommendations,
invasive procedures are often first offered to patients, with no alternative options
being discussed. In treatment scenarios with a lot of clinical equipoise (i.e.
uncertainty about what treatment would be best) and a rapidly growing market for
newly-introduced technologies, including medical devices for invasive PAD procedures
(e.g. stents for endovascular treatment), with limited performance measurement and
accountability criteria, there is a high risk of unwanted variation in treatment
practices, misallocation of treatments, and unnecessary costs.
Given this context, some of the current challenges in current PAD care include: 1)
limited access to the evidence-base in routine clinical care for patients and providers;
2) the potential mismatch of PAD treatments to patient preferences and profiles; and 3)
patients not being informed or engaged in medical decision making. These challenges may
leave patients uninformed about treatment risks and benefits, increase the risk of
misallocating treatments to patients, and may unnecessarily increase costs. A very
promising strategy to overcome these challenges is the use of evidence-based, decision
support tools. Importantly, it is currently unknown whether patient-centered PAD
decision-tools can be designed to improve the alignment of patients' values with respect
to their treatment choice and whether these tools can improve patients' knowledge and
access to the evidence-base related to PAD treatment and outcomes. The critical next
step, therefore, is to create such tools and pilot their implementation as a foundation
for broader integration of precision medicine and shared decision-making in clinical
care.
Shared decision-making takes into account the latest evidence about all available
treatment options and their outcomes, as well as patients' values and preferences with
regards to treatment and potential outcomes that matter to them. Shared decision-making
is extremely useful in treatment situations where there is clinical equipoise and where
the choice of treatment should be greatly influenced by patients' preferences. Decision
aids that facilitate this process of shared decision-making, have been consistently
associated with better knowledge about the disease and treatments, less decisional
conflict, and potential cost savings due to less invasive options being preferred by
patients.