BMN Blog

Over 10 million people in the Unites States and over 200 million worldwide have peripheral arterial disease (PAD).¹ Critical limb ischemia (CLI), defined as ischemic rest pain or tissue loss resulting from arterial insufficiency, affects approximately 1% of the adult population, or 10% of patients with PAD.² Further increasing the impact of CLI is the poor prognosis it carries. Major amputation occurs in 33-67% of patients with ischemic tissue loss at 4 years.^3,4 Mortality at 2 years in CLI patients is as high as 40%, and appears to be even higher in those with tissue loss. The vast majority of these deaths are due to cardiac events, cardiovascular disease, and cancer, rather than PAD.^4,5

Most patients with CLI who see a vascular interventionist are primarily concerned about limb loss.⁶ Until recently, the metrics used to evaluate the durability of revascularization procedures has reflected patients who survived to the end of the analysis: amputation free survival (AFS) and freedom from amputation (FFA).⁷ Though these statistics are certainly useful, they do not accurately answer CLI patients’ most common question: “Will I ever lose my leg?” AFS excludes patients who do not survive to the study endpoint, and patients who die during a research trial are censored from the calculation of FFA.

To address the need for a statistical tool to account for patients who never undergo amputation prior to passing away, Dr. Katie Shean and other researchers in Boston and Washington DC developed a new measurement: Lifelong Limb Preservation (LLP). Published in the Journal of Vascular Surgery in May 2017, their study shows that 7 years after revascularization, CLI patients had AFS of 14%, FFA of 78%, and LLP of 86%. Among patients without tissue loss, the LLP was 92%. The researchers also found that minimally invasive endovascular procedures were equivalent to open surgical reconstructions in terms of LLP.

I believe this measurement will fit into our overall understanding of PAD and the way we counsel our patients. We as interventionists need to understand its meaning and limitations. It’s very important for patients with PAD to recognize the associated cardiovascular risks, and any discussion of prognosis in CLI must include the issue of mortality. However, when preparing a patient for a vascular intervention, LLP can be cited in assuring the CLI patient that their procedure will be durable and has a very high probability of preventing amputation. As technology and knowledge of vascular disease and treatment continues to improve by leaps and bounds, all physicians will be better equipped to care for this challenging and important patient population.

For questions and information about the services we offer, please contact Alabama PVD Center at 205-209-3584, or via email at pvdsupport@alpvd.com.

References

1. Fowkes FG, Rudan D, Rudan I, et al. Comparison of global estimates of prevalence and risk factors for peripheral artery disease in 2000 and 2010: a systematic review and analysis. Lancet. 2013;382(9901): 1329– 1340.
2. Norgren L, Hiatt WR, Dormandy JA, et al. Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II). Eur J Vasc Endovasc Surg. 2007;33(suppl 1): S1– S75.
3. Nehler MR, Duval S, Diao L, et al. Epidemiology of peripheral arterial disease and critical limb ischemia in an insured national population. J Vasc Surg. 2014;60(3): 686– 695. e682.
4. Farber A, Eberhardt R. The current state of critical limb ischemia: a systematic review. JAMA Surgery. 2016;151(11): 1070-1077.
5. Rothwell P, Coull A, Silver L, et al. Population-based study of event-rate, incidence, case fatality, and mortality for all acute vascular events in all arterial territories (Oxford Vascular Study). Lancet. 2005;366(9499): 1773– 1783.
6. Crosby FE, Ventura MR, et al. Well-being and concerns of patients with peripheral arterial occlusive disease. J Vasc Nursing. 1993;11(1): 5-11.
7. American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. 2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease. J Am Coll Cardiology. 2017;69(11): e71-e126.
8. Shean KE, Soden PA, Schermerhorn ML, et al. Lifelong limb preservation: A patient-centered description of lower extremity arterial reconstruction outcomes. J Vasc Surg. 2017;66(4): 1117-1122.