Could prior endovascular interventions affect the results of lower extremity below the knee autologous vein bypasses?

Background: Performing a non-selective primary endovascular approach involves risk of performing ineffective procedures and could compromise future treatments. The objective of this research is to determine if previous failed endovascular intervention could affect bypass results. Methods: Retrospective cohort study including 77 below the knee (BTK) bypasses with great saphenous vein (GSV) in patients with critical limb ischemia, carried out between 2008-2018. Primary bypasses (P-BP) were compared with bypasses with history of previous failed endovascular intervention (Secondary bypasses [S BP]). Primary outcomes included: primary, primary-assisted, and secondary patency, and major amputation free survival (AFS). The quality of GSV used was evaluated as a potential confounding factor. Results: Forty-six procedures were P-BP (59.7%) and 31 S-BP (40.3%). The mean follow-up was 35.4 (SD: 31) and 28 (DS: 30) months respectively. Univariate results showed an increased risk of loss of primary patency (HR=2.7), primary-assisted patency (HR=3.1) and secondary patency (HR=3.26) in S-BP (P<0.05). This group also presented a trend towards an increased risk of major amputation (HR=1.6; P>0.05). Suboptimal GSV was used in 29% of S-BP and 15% of P-BP. This factor was identified as confounding partially, as it decreased the influence assumed by the history of prior endovascular intervention in the analyzed variables. Conclusions: Secondary bypasses show inferior results to primary bypasses in our series. Although the cause could be a prior failed endovascular intervention, the frequent use of suboptimal GSV in this type of patients may also contribute to this effect.