Adopting An Integrated Practice Model of Care for Critical Limb Ischemia & Limb Preservation in the Outpatient Wound Clinic

In the last 20-plus years we’ve witnessed the evolution of wound care as a specialty and, along with it, the development of an interdisciplinary team approach to the management of wounds.  While the etiology of nonhealing wounds seems at times limitless, the management of wounds for patients experiencing underlying arterial and venous peripheral artery disease (PAD) has paralleled the epidemic of diabetes as well as the emergence of wound management centers. The emergence of endovascular intervention by cardiologists, radiologists, and vascular surgeons has allowed for the integration of wound healing and vascular medicine into the subspecialty of “limb salvage” along with the first wave of limb-preservation centers. Limited randomized, controlled trials involving wound care products has partly been responsible for a Wild West mentality within the wound care community. While attempts have been made to provide levels of evidence to support treatment recommendations (offloading of the diabetic foot,¹ for example), the practice of wound care is still steeped in subjective factors that are often based on the opinions and experience of the individual practitioner. Moving beyond the realm of wound care, the same statements apply to the management of vascular disease, namely PAD and its most extreme form — critical limb ischemia (CLI).

As our population ages and the number of those living with diabetes increases, wound care providers and vascular specialists have been drawn together in practice settings that are the natural progression in treating limb-threatening wounds. The “toe and flow” model,² the often-cited five-year mortality rates for nonhealing diabetic foot ulcers (DFUs) and PAD,³ and the bleak outlook for amputees⁴ should be familiar to most wound care providers by now. The advent of amputation-prevention or limb-preservation centers has begun to further address this area of need. Now more than ever, validation of our efforts is critical considering the scrutiny we as providers are under in caring for a population that is viewed as a significant economic burden by our critics. To better understand the mutual issues shared by the wound care and vascular disease communities, CLI is examined as a medical condition, the focus of a practice model in a dedicated center setting, and as an example of the future of our healthcare system. This article will offer an overview of CLI and its impact on healthcare, and present an integrated model of care approach to facilitating prevention of advanced vascular disease and coordinated treatments. 

CLI: The Disease State 

PAD is the natural extension of coronary artery disease. Even though they are technically different diseases, both are clinical manifestations of atherosclerosis. PAD affects an estimated 200 million people worldwide and the risk of acute myocardial infarction, stroke, or cardiovascular death among patients exceeds that of patients living with established cerebrovascular disease.⁵

CLI represents advanced PAD and is characterized by chronic ischemic pain while the individual is “at rest,” ulcers or gangrene in one or both legs, and objectively proven arterial occlusive disease.⁶ Tissue loss or ulcers associated with CLI are typically exquisitely painful, even in cases where patients are afflicted with sensory loss due to peripheral neuropathy. The Rutherford-Becker Categorization of PAD specifies the extent of symptoms from asymptomatic to those seen in CLI (Rutherford-Becker categories 4-6). Rutherford-Becker Categories include: 0 – asymptomatic; 1 – mild; 2 – moderate; 3 – severe; 4 - ischemic rest pain; 5 - minor tissue loss, such as a nonhealing ulcer or focal gangrene; and 6 - major tissue loss above the transmetatarsal level.⁷ 

CLI: Economic Drain

Mary L. Yost, president of the SAGE Group, a company based in Atlanta that focuses on research and the economics of peripheral vascular disease, has long been an advocate for lower extremity preservation versus amputation. At the opening session of the 4th annual Amputation Prevention Symposium in Chicago last year, Yost delivered a lecture titled “Cost of Amputation in 2014.” According to Yost, “approximately 65,000-75,000 major amputations (above the knee and below the knee) are performed annually for CLI.  Within five years, approximately 70% of CLI patients die. These cost $11 billion with Medicare and Medicaid paying almost 80% of the bill. In addition to major amputation (MA), 134,000 minor amputations (eg, toe, foot, and partial foot) are performed annually for CLI. These add another $13.6 billion to the bill.” Furthermore, “frequent re-amputation is one of the reasons the costs are so high. Annual re-amputation rates for foot (28%) and toe (24%) amputations exceed those of major amputations,” she said, adding, “CLI amputees experience a high rate of hospitalizations and mortality, especially due to underlying cardiovascular disease. Amazingly, minor amputees experience these adverse events at the same rates as major amputees. For example, three-year cardiovascular mortality is about 20% while all-cause mortality is 29% for both major and minor amputations.” Additionally, according to Yost, $25 billion understates the cost of CLI amputations, as this figure represents direct costs only and does not include patient costs or the economic costs of lost productivity and mortality to society. Patient costs are significant, reflecting lost wages of the patient and family caregiver, copayments, and deductibles as well as modifications for disabled living, such as handrails, wheelchair ramps, and wheelchair accessible transportation.⁸ CLI in the United States has been characterized as a “pathway to amputation” by Allie et al, who found amputation as the first procedure in 67% of Medicare patients who underwent MA.⁹ A 2012 study of 20,464 Medicare patients living with CLI who underwent MA found strikingly similar results: 71% had either no revascularization or only one diagnostic procedure in the year immediately preceding an MA.¹⁰

CLI: Management & Prevention

Despite the alarming amputation statistics, intuitively the progression of PAD to CLI seems largely preventable. Even with the myriad literature describing the basic problem of PAD, the public and majority of primary care physicians play a limited role in screening and early identification of the disease. The lack of comprehension and disconnect regarding PAD and CLI among these two groups at opposite ends of the medical spectrum is a stark contrast to groups such as women’s health, which are more involved in active recognition, screening, and proactive practice patterns. Why patients afflicted with PAD should deteriorate into ones with CLI is analogous to witnessing forms of treatable cancer going unrecognized or disregarded until only palliative measures can be offered. A practice model of podiatrists working closely with interventional cardiologists, radiologists, and vascular surgeons has become increasingly accepted for lower extremity preservation. Likewise, we know the team approach to wound care and limb preservation has been proven to be necessary, efficacious, and efficient. Zayed et al reported results of a retrospective analysis of 312 patients living with diabetes and CLI and demonstrated a reduction in amputation rate in a multidisciplinary setting. The team was composed of a vascular and podiatric surgeon, diabetologist, tissue-viability nurse, interventional radiologist, and a radiology coordinator.¹¹ Driver et al found implementation of the team approach to manage DFUs within a given region or healthcare system has been reported to reduce long-term amputation rates from 82% to 62% and limb-salvage efforts may include aggressive therapy, such as revascularization procedures and advanced wound healing modalities.¹²

Unfortunately, recognition of PAD often comes in the later stages when the disease has transitioned to a far more difficult entity to successfully treat. CLI teams are needed to appropriately treat limb-threatening arterial disease, as this group of patients often represents the most challenging subset of wound care patients. Typical medical practices and wound centers alike have utilized the traditional procedure-driven fee-for-service model of reimbursement. This system is being phased out in favor of performance-based reimbursement. Porter and Lee proposed a model for value-based care¹³ focusing on six key components (see Figure 1). The first step in their proposal is the creation of integrated practice units (IPUs), which are suggested to organize around the customer/patient and the need. This requires a shift from “siloed” organization by specialty departments and discrete service to organizing around the patient’s medical condition. For example, most of today’s wound clinics may function in a capacity that sees specialists, though technically practicing under one roof, not interacting with each other. Although they may be treating patients at the local wound center, providers tend to manage patient care individually, even if following established, universal facility protocols. What has been missing is the concept of the dedicated team comprised of clinical and nonclinical personnel providing the full care cycle for the patient’s condition. 

Concepts Of The IPU

IPUs treat a disease and related conditions, complications, and circumstances that commonly occur, such as kidney and eye disorders for patients living with diabetes. Clinicians not only provide the treatment, they also assume responsibility for engaging patients and families in care — for instance, providing education and counseling, encouraging adherence to treatment and prevention protocols, and supporting needed behavioral changes such as smoking cessation and/or weight loss. In an IPU, personnel works together regularly as a team toward a common goal: maximizing the patient’s overall outcomes as efficiently as possible. Consider: 

• Staff members are experts in the conditions they’re treating, know and trust one another, and coordinate easily to minimize wasted time and resources.
• Staff members meet frequently (formally and informally) and review data on their own performance. 
• Armed with data, staff works to improve care by establishing new protocols and devising better or more efficient ways to engage patients, including group visits and virtual interactions.
• Ideally, IPU members are co-located to facilitate communication, collaboration, and efficiency for patients, but they work as a team even if they’re based at different locations.
• Organizing into IPUs makes proper measurement of outcomes and costs easier.
• Organizations that progress rapidly in adopting the value agenda will reap huge benefits, even if regulatory change is slow.
• Measuring outcomes is likely to be the first step in focusing everyone’s attention on what matters most.
• Better measurement of outcomes and costs makes bundled payments easier to set and agree upon.
• With bundled prices in place, IPUs have stronger incentives to work as teams and to improve the value of care.¹³

Based on this overview of one aspect of the six outlined by Porter and Lee in their proposed value-based care model, an opportunity exists for the creation of integrated wound care and limb-preservation centers, with the caveat that true integration means alignment of skill sets and patient-centered engagement among providers being essential.¹³ Existing wound centers must look at their current business model and objectively assess the present effectiveness of their interdisciplinary team and the communication, or lack thereof, between specialists. For example, regular dialogue and discussion of cases must occur between interventionists, wound care providers, vascular technicians, and wound center administrators, among others. Such communication cannot be unilateral between administration and individual providers. As mentioned earlier, wound care among providers reveals treatment and protocol variations that when compared to management of any form of cancer, would likely be open to question. This statement is based on the fact that levels of evidence and robust clinical trials in wound care with recognized clinical practice guidelines, for whatever the reasons, are not on par with those found in cancer management. The eye-opening, five-year mortality rates comparing nonhealing DFUs and PAD with various forms of cancer may in part be a reflection not of the disease states, but more so the lack of homogeneity in their treatment. There is a similar lack of cohesiveness among vascular and endovascular interventionists that can be said to exist regarding wound care providers. Despite the emergence of technology that has created a paradigm shift in the way limb preservation and wound care is perceived and practiced, lack of clearly agreed-upon endpoints that define successful intervention have yet to be attained.

Final Thoughts

The burden of diabetes-related complications to the healthcare system is unprecedented. CLI is enigmatic in that in its earlier form as PAD, whether symptomatic or not, it’s often overlooked. It is not until it becomes life- and limb-threatening that it receives appropriate attention. Yet, this later stage is the focus of development of new limb-saving technologies and where many resources are expended. Synergy between wound care providers and vascular/endovascular specialists has the potential to optimize patient outcomes amidst increasing scrutiny. Organizing limb-preservation teams into IPUs has the potential to make measurement of outcomes and costs easier while delivering quality and value to patients: It is the most efficient model for which lower extremity limb preservation is concerned. Those wound care clinicians who successfully adopt the IPU model into their wound care/limb-preservation centers will be rewarded as reimbursement shifts to pay for performance and the value-based agenda.¹³ 

Desmond Bell is on staff at First Coast Cardiovascular Institute P.A., Jacksonville, FL, and is president and founder of The Save A Leg, Save A Life Foundation.

References 

1. Snyder, RJ, Frykberg RG, Rogers LC, et al. The management of diabetic foot ulcers through optimal offloading. J Am Podiatr Med Assoc. 2014;104(6): 555-67. 

2. 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(3 Suppl):23S–27S. 

3. Armstrong DG, Wrobel J, Robbins JM. Guest editorial: are diabetes-related wounds and amputations worse than cancer? Int Wound J. 2007;4(4):286-7.

4. Bertoni AG, Krop JS, Anderson GF, Brancati FL. Diabetes-related morbidity and mortality in a national sample of U.S. elders. Diabetes Care. 2002;25(3):471-5. 

5. Jancin B. AHA: New Spotlight on Peripheral Arterial Disease. Cardiology News Digital Network. 2015. Accessed online: www.ecardiologynews.com/specialty-focus/cad-atherosclerosis/single-article-page/aha-new-spotlight-on-peripheral-artery-disease/084c592e363be7928eda0a9ab13ee243.html

6. Novo S, Coppola G, Milio G. Critical limb ischemia: definition and natural history. Curr Drug Targets Cardiovasc Haematol Disord. 2004;4(3):219-25.

7. Bell D. Peripheral arterial disease overview: update. Pod Manage. 2013;January:175-82.

8. The SAGE Group Estimates the Economic cost of Critical Limb Ischemia Costs at $25 Billion. The SAGE Group. Accessed online: www.businesswire.com/news/home/20140815005003/en/correcting-replacing-sage-group-estimates-economic-cost

9. Allie DE, Hebert CJ, Lirtzman MD, et al. Critical limb ischemia: a global epidemic. A critical analysis of current treatment unmasks the clinical and economic costs of CLI. EuroIntervention. 2005;1(1):75-84.

10. Goodney PP, Travis LL, Nallamothu BK, et al. Variation in the use of lower extremity vascular procedures for critical limb ischemia. Circ Cardiovasc Qual Outcomes. 2012;5(1):94-102.

11. Zayed H, Halawa M, Maillardet L, Sidhu PS, Edmonds M, Rashid H. Improving limb salvage rate in diabetic patients with critical leg ischemia using a multidisciplinary approach. Int J Clin Pract. 2009;63(6):855–8.

12. Driver VR, Fabbi M, Lavery LA, Gibbons G. The costs of diabetic foot: the economic case for the limb salvage team. J Vasc Surg. 2010;52(3 Suppl):17S-22S.

13 Porter ME, Lee TH. The Strategy That Will Fix Health Care. Harvard Business Review. 2013. Accessed online: https://hbr.org/2013/10/the-strategy-that-will-fix-health-care