Effects of PCSK9 Inhibitor on Favorable Limb Outcomes in Patients with Chronic Limb-Threatening Ischemia

Aim: The aim of this study was to examine the effects of evolocumab on favorable limb events in patients with chronic limb-threatening ischemia (CLTI). Methods: A single-center, prospective observational study was performed on 30 patients with CLTI. The subjects were divided into 2 groups based on evolocumab administration: evolocumab-treated (E) group ( n=14) and evolocumab non-treated (non-E) group (n=16). The primary outcome was 12-month freedom from major amputation. The secondary outcomes were 12-month amputation-free survival (AFS), overall survival (OS), and wound-free limb salvage. The mean follow-up period was 18±11 months. Results: No significant difference was detected between the two groups for the 12-month freedom from major amputation (log-rank p=0.15), while the 12-month AFS rate was significantly higher in the E group than that in the non-E group (log-rank p=0.02). The 12-month OS rate in the E group was shown a tendency for improvement, as compared with that in the non-E group (log-rank p=0.056). Evolocumab administration was not associated with a significant change in freedom from major amputation (HR, 0.23, 95% CI, 0.03-2.07, p=0.19). However, evolocumab administration was related to a tendency for improvement of AFS and OS (HR, 0.13, 95% CI, 0.02-1.06, p=0.056; HR, 0.16, 95% CI, 0.02-1.37, p=0.09, respectively). Moreover, The E group had a higher proportion of wound-free limb salvage at 12 months (92% vs. 42%, p=0.03). Conclusion: Evolocumab administration was associated with a better AFS outcome in patients with CLTI. Long-term administration of evolocumab over 12 months contributed to improving proportion of wound-free limb salvage.