A systematic review of the accuracy of prognostic tests and scoring systems for use in the Global Vascular Guidelines' PLAN concept for the treatment of chronic limb threatening ischaemia

Introduction: The 2019 Global Vascular Guidelines recommend risk assessment for evidence based revascularization based on the acronym PLAN; Patient risk, Limb severity and ANatomical complexity of disease. This meta-analysis compares a multitude of prognostic tests within these categories.

Methods: A systematic review and meta-analysis of tests that estimated 1 year major event (amputation free survival and major adverse limb events) probability. Individual patient data were reconstructed from survival estimate curves. With presence or absence of major events; sensitivity, specificity and area-under-receiver operating characteristics curves (AUC) were computed. Tests with an AUC ≥70%, or that correlated with revascularization feasibility were included. Practical application of tests was assessed to make a recommendation on PLAN implementation.

Results: Ninety-six studies describing 77 unique predictive techniques were included, of which thirteen were sufficient. These 13 tests were divided in 4 Patient risk (5 studies), 3 Limb severity (3 studies) and 6 Anatomical complexity of disease (9 studies).

Patient risk: Three tests were included; Biochemical assessment of calprotectin and CRP, radiological measurement of sarcopenia and predictive score with the GermanVasc CLTI score. These tests scored AUCs of 82.0%, 72.7% and 71.8% respectively, of which the GermanVasc CLTI score was deemed most applicable in clinical practice.

Limb severity: The adjusted Wound Ischemia foot Infection score resulted as best predictive score (AUC 78.8%), but due to the lack of external validation, the original Wound, Ischemia, foot Infection score was deemed best applicable.

Anatomical complexity of disease: No test surpassed 70% AUC for 1-year event estimation, and was correlated with feasibility of revascularization, the latter only being served by the Global Limb Anatomic Staging System (GLASS).

Conclusion: In evidence based revascularization in patients with CLTI according to the PLAN concept, we recommend to use GermanVasc, Wound Ischemia and Foot Infection, and the Global Limb Anatomic Staging System.