First results with "immunologic bypass" strategy in no-option chronic limb-threatening ischemia: a case series.

Introduction: Revascularization interventions are the gold-standard treatment to obtain limb salvage in chronic limb-threatening ischemia (CLTI). Unfortunately, almost 15% of patients are not eligible. Recent studies stressed the possible role of peripheral-blood mononuclear cells (PB-MNCs) promoting postnatal vasculogenesis in no-option CLTI patients through monocytes, reducing mortality and limb loss. In this case series, we present our first results with this clinical approach. Presentation of cases: We treated 18 no-option CLTI patients (with diabetes or vasculitis) with autologous cellular therapy using PB-MNCs in the last 6 years in our center. Eighty-nine percent of patients presented with foot lesions. The mean age of our patients was 72 years (43-90 years). Mean follow-up was 21.8 (2-48) months, and the median follow-up was 15 months. During the follow-up, we registered one major amputation at 1 month and another major amputation at 25 months. Two patients died, respectively, at 2nd and 3rd month follow-up (12th month death rate of 11%), and a third one died at 13 months follow-up (long-term death rate of 6%). All deaths were for causes not related to sepsis. Discussion: Our results are promising: at 12-month follow-up, only one patient had a major amputation intervention (5.6%), and two patients died (11%). These results are better than recent evidence in literature, even though the 2019 European Society for Vascular Surgery guidelines consider this therapy investigational. Conclusion: In our experience, use of PB-MNCs in no-option CLTI patients appears safe and effective. Larger, controlled studies are needed, in particular with non-diabetic CLTI patients, to confirm these results.