Chapter I: Definitions, epidemiology, clinical presentation and prognosis

Area of Science:

• Vascular Medicine
• Medical History
• Public Health

Background:

• Chronic critical limb ischemia (CLI) is a severe manifestation of peripheral arterial occlusive disease (PAOD).
• Historical definitions of CLI have varied significantly, complicating comparisons of epidemiological data and clinical studies over time.
• The high prevalence and management costs of CLI present a significant public health challenge.

Purpose of the Study:

• To review the historical evolution of CLI definitions.
• To highlight the impact of changing definitions on research and clinical practice.
• To emphasize the need for standardized diagnostic criteria for CLI.

Main Methods:

• Historical review of CLI classification systems, including Fontaine, Rutherford, and TASC.
• Analysis of diagnostic criteria, focusing on clinical symptoms and hemodynamic measurements (ankle pressure, toe pressure, TcPO(2)).
• Examination of consensus documents and interventional study inclusion criteria.

Main Results:

• Early CLI definitions relied solely on clinical symptoms, while later classifications incorporated objective hemodynamic criteria.
• Subsequent consensus documents (e.g., TASC) introduced less stringent pressure cut-offs, potentially including less severe cases.
• Variations in inclusion criteria across studies hinder the comparison of natural history and treatment outcomes for CLI patients.

Conclusions:

• CLI, when defined by consistent clinical and hemodynamic criteria, remains a severe condition with poor prognosis and high healthcare costs.
• Standardized diagnostic criteria are essential for accurate epidemiological assessment and for evaluating advancements in CLI management.
• Future efforts should focus on applying standardized definitions to improve the comparability of research and optimize patient outcomes.