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Diagnosis, treatment of CLI remain challenging
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HOLLYWOOD, Fla. — A lack of standardization in nomenclature, definition and staging complicates the diagnosis and treatment of critical limb ischemia, according to a speaker at the International Symposium on Endovascular Therapy.
During his presentation, Alik Farber, MD, of Boston University School of Medicine, said chronic ischemia, chronic CLI, critical ischemia and severe limb ischemia have all been used to describe a broad spectrum of patients, but the question of which term best characterizes the disease has gone unanswered.
Similarly, the definition of CLI has undergone several iterations. For example, some previous definitions excluded hemodynamic criteria. The most recently revised definition is outlined in the 2016 American Heart Association/American College of Cardiology guidelines.
Staging systems for CLI are also flawed because they only consider hemodynamic compromise and not other factors that may affect outcomes, Farber said. For instance, infection and degree of tissue injury are important factors that predict amputation risk and the success of revascularization and, therefore, cannot be ignored when evaluating patients with CLI.
Recently, the Society for Vascular Surgery convened a group of experts and developed a new staging system for CLI — the WIFI Index — based on wounds, ischemia and foot infection that may have some promise, according to Farber. The system is based on available data and is designed to be analogous to the TNM staging system for cancer. It employs a four-point scale to describe wounds, ischemia and the degree of foot infection. A group of experts classified each vascular presentation based on one to four classes of stages using two considerations: 1-year risk for amputation and likelihood that the patient would benefit from revascularization.
There is also significant variation in CLI treatment. Many physicians may treat CLI with endovascular therapy first, followed by bypass surgery if the treatment fails, but evidence supporting this strategy is lacking, according to Farber.
To answer these questions, Farber and colleagues are conducting the NIH-funded BEST-CLI trial. The prospective, randomized, multicenter, multispecialty, open-label superiority trial aims to enroll 2,100 patients at 160 clinical sites in North America and is designed to assess outcomes, quality of life and cost-effectiveness of treatments for CLI. The researchers are also using a novel endpoint — major adverse limb event-free survival — that may be better for assessment of outcomes than endpoints commonly used in other studies, such as death, amputation and major reinterventions, he noted.
“Current management of CLI is marred by geographic variability, treatment variability and undertreatment, and BEST will provide a treasure trove of invaluable data on CLI and its management,” Farber said. – by Melissa Foster
Reference:
Farber A. Opening Session: Town hall: Managing the epidemic of critical limb ischemia. Presented at: International Symposium on Endovascular Therapy; Feb. 4-8, 2017; Hollywood, Fla.
Disclosure: Farber is co-chair of the BEST-CLI trial sponsored by the NHLBI.