Disparities in the Care of Patients with Peripheral Artery Disease and Critical Limb Ischemia

Despite improvements in technology, interventional therapies, medications, and awareness, there remain disparities in the care of patients with peripheral artery disease (PAD). The Department of Health and Human Services has made the elimination of such healthcare disparities a goal of paramount importance. In a presentation entitled "Underdiagnosis and Undertreatment of PAD" at the 2015 Medicare Evidence Development and Coverage Advisory Committee (MEDCAC), Joshua Beckman, MD proclaimed "PAD is the disparity" by illustrating to a room of clinicians, regulators, and payers how the evidence for under-diagnosis and under-treatment of PAD continues to grow. To fully understand disparities in the care of patients with PAD requires a basic understanding of the trends and treatment variation that occurs commonly in the care of these patients. As our population ages, the incidence of PAD and critical limb ischemia is becoming increasingly more prevalent. This can be attributed, at least in part, to the escalating percentage of our population over the age of 65 and the increased prevalence of diabetes mellitus and obesity. Major lower extremity amputation rates have declined over the past decade, while the rates of revascularization procedures (particularly endovascular procedures) have skyrocketed. Yet, guidelines regarding medical therapy are very similar to those created over one decade ago, and adherence rates to optimal medical therapy remain very low.

In addition to the proclamation that "PAD is the disparity," two factors have repeatedly been associated with differences or disparities in the care of patients with PAD: sex and race. The remainder of this article will focus on these two factors and what is needed to mitigate or eliminate these disparities and improve the care of all patients with this chronic disease.

Sex-related Disparities

Sex-related differences in treatment strategies and outcomes have been observed in many different cardiovascular disease processes. For example, despite tremendous progress in the care of patients with ST-segment elevation myocardial infarction (STEMI), women have a significantly higher unadjusted and adjusted risk of in-hospital mortality after STEMI when compared with men. In patients with vascular disease, women have a higher rate of rupture with abdominal aortic aneurysms (AAA) at equivalent diameters when compared with men. Furthermore, their perioperative mortality after open abdominal aortic aneurysm repair is higher as well. In a landmark study for the treatment of symptomatic carotid artery disease, female sex was associated with a reduced benefit compared to their male counterparts following carotid endarterectomy for symptomatic disease. The etiology of these differences are debatable and are most likely multifactorial, encompassing age at presentation, hormonal differences, social factors, and anatomical differences.

The disparities based on sex with regard to critical limb ischemia remain a focus for cardiologists, vascular medicine clinicians, and surgeons. A recent meta-analysis exploring the effect of sex on outcomes following lower extremity revascularization demonstrated that women had significantly higher risk of 30-day mortality and major amputation following both endovascular and/or open surgical revascularization. Furthermore, the study concluded that women had worse outcomes with regard to early graft thrombosis, vascular access complications, cardiac and pulmonary events, and stoke following revascularization. Furthermore, these differences in perioperative mortality and outcomes were maintained when stratified based on surgical approach, endovascular versus open. However, when studying the long-term outcomes of this meta-analysis, these sex differences did not persist.

In the largest longitudinal study of CLI disparities from the Healthcare Utilization Project Nationwide Inpatient Sample (NIS) from 2002 to 2011, women maintained a higher ratio of above-knee amputations to below-knee amputations when compared with men. This difference in amputation level often leads to reduced mobility, poorer functional status, and ultimately higher morbidity and mortality. These findings were corroborated in a separate study from the NIS data from 1998 to 2002 showing that women with limb ischemia were found to be more likely to undergo a major amputation when compared with men. While other studies have refuted this data, higher quality, prospective studies are needed to understand which factors are important regarding sex-related disparities.

Disparities Associated with Race

Epidemiologic studies have demonstrated that PAD is significantly more prevalent in the African-American population as compared to the Hispanic and non-Hispanic white population across all age groups. This fact mirrors the disproportionate rates of cardiovascular disease and cardiovascular events (myocardial infarction, stroke, and heart failure) seen in African-American patients. While African-Americans are more likely to have CLI on initial presentation, the fact that rates of major amputation are significantly higher in African-American patients is cause for alarm. Rates of limb-salvage open revascularization and endovascular revascularization procedures are also disproportionately low. These patterns of African-American patients being significantly less likely to receive aggressive limb salvage procedures and significantly higher amputations is not a recent phenomenon and has not changed dramatically over the last two decades.

Regrettably, even outcomes following surgical or endovascular revascularization are worse for African-American patients when compared with non-Hispanic white patients. For example, following endovascular interventions for PAD, African-Americans and Hispanics had an increased risk of major amputation within 30 days of intervention and a lower amputation-free survival at 1 year compared to non-Hispanic whites. Additionally, a recent analysis of more than 16,000 patients who underwent open infrainguinal bypass found a higher rate of early graft failure in African-Americans despite no difference in the use of autogenous conduit across groups.

Some have suggested that these racial disparities regarding revascularization are due to lack of access; however, more recent studies identified these same broad disparities at centers with robust revascularization capabilities, demonstrating that access is not the only factor that contributes to these disparities. Biologic differences among patients of different races and ethnicities have also been proposed as a potential etiology given the higher prevalence of diabetes and metabolic syndrome within the African-American population. However, comparisons of non-diabetic cohorts of both African -American and white PAD patients demonstrated that non-diabetic African-American had a higher likelihood of undergoing major amputation compared to non-diabetic whites. Furthermore, previous studies that controlled for diabetes still found that blacks were less likely to receive limb salvage revascularization.

Approach to Mitigating Disparities

There is no question that the PAD community needs to perform high-quality, real world studies of patients with critical limb ischemia. These studies, along with recognition of disparities of care, have the chance to improve the overall care of patients with advanced forms of vascular disease.

Within the Duke University Health System, we have adopted a widely-described approach to the treatment of patients with PAD/CLI that involves multifaceted, collaborative, multidisciplinary care teams that rely on three basic concepts. First, we believe that improving disease awareness in the local/regional community and facilitating access across the full patient spectrum will reduce the potential barriers to seeking care at a medical facility with vascular specialists that have expertise in limb salvage. Second, skilled and timely interventions with a keen eye and ear open to patient preferences and addressing critical questions about risk/benefit/alternatives are essential. Intervention on patients with ischemic rest pain/ulceration (i.e., mild to moderate end of the disease spectrum) followed by preventative measures (medical therapy, behavior/diet modification, risk profile enhancement, smoking cessation, etc.) can mitigate disease progression and ultimately improve clinical outcomes. Finally, interdisciplinary collaboration and continuity of care are indispensable. The popularized "toe and flow" model demonstrates the benefits of a collaborative team approach in dealing with arterial insufficiency in the setting of lower extremity tissue loss. The use of a multispecialty team ensures that all intervention options are identified and available. Furthermore, the diversity of medical expertise provides a comprehensive knowledge base and ability to deliver creative and effective cutting edge treatment. This collaborative approach also allows for continuous care that is delivered in hospitalized patients, patients undergoing revascularization in outpatient or office-based clinics, and patients seeking preventative and/or follow up care in the clinic setting.

References

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  2. Hirsch AT, Allison MA, Gomes AS, et al. A call to action: women and peripheral artery disease: a scientific statement from the American Heart Association. Circulation 2012;125:1449-72.
  3. Rogers LC, Andros G, Caporusso J, Harkless LB, Mills JL Sr, Armstrong DG. Toe and flow: essential components and structure of the amputation prevention team. J Vasc Surg 2010;52:23S-7S.
  4. Wang J, He Y, Shu C, Zhao J, Dubois L. The effect of gender on outcomes after lower extremity revascularization. J Vasc Surg 2017;65:889-906.
  5. Lefebvre KM, Chevan J. The persistence of gender and racial disparities in vascular lower extremity amputation: an examination of HCUP-NIS data (2002-2011). Vasc Med 2015;20:51-9.
  6. Selvarajah S, Balck JH 3rd, Haider AH, Abularrage CJ. Racial disparity in early graft failure after infrainguinal bypass. J Surg Res 2014;190:335-43.
  7. Hughes K, Boyd C, Oyetunji T, et al. Racial/ethnic disparities in revascularization for limb salvage: an analysis of the National Surgical Quality Improvement Program database. Vasc Endovasc Surg 2014;48:402-5.
  8. Holman KH, Henke PK, Dimik JB, Birkmeyer JD. Racial disparities in the use of revascularization before leg amputation in Medicare patients. J Vasc Surg 2011;54:420-6.
  9. Loja MN, Brunson A, Li CS, et al. Racial disparities in outcomes of endovascular procedures for peripheral arterial disease: an evaluation of California hospitals, 2005-2009. Ann Vasc Surg 2015;29:950-9.
  10. Durazzo TS, Frencher S, Gusberg R. Influence of race on the management of lower extremity ischemia: revascularization vs amputation. JAMA Surg 2013;148:617-23.

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