Factors Affecting Patency of In Situ Saphenous Vein Bypass: Two Year Results from LIMBSAVE (Treatment of critical Limb Ischaemia with infragenicular Bypass adopting in situ SAphenous VEin technique) Registry

Objective: The aim was to demonstrate contemporary outcomes of in situ saphenous vein bypass using a valvulotome.Methods: Analysis of two year outcomes of a multicentre registry based on the treatment of critical Limb Ischaemia with infragenicular Bypass adopting in situ SAphenous VEin technique (LIMBSAVE). Between January 2018 and December 2019, 541 patients in 43 centres were enrolled. In all patients an innovative valvulotome was used. Early outcomes were assessed. Two year outcomes according to KaplaneMeier curves in terms of patency and limb salvage were evaluated. Associations between patient and procedure variables were analysed with univariable and multivariable analyses.Results: In all cases, a valvulotome was able to lyse the valves. Vein injury due to the in situ technique was 3.5%. Thirty day mortality and major amputation rates were 3% and 0.9%, respectively. Mean follow up was 12.1 months. Two year estimated primary patency, primary assisted patency, secondary patency, and limb salvage were 69.1%, 81.4%, 86.5%, and 94.5%, respectively. Multivariable analysis showed an association between pre-operative vein diameter < 3 mm and lower primary patency (hazard ration [HR] 14.3, p <.001), primary assisted patency (HR 9.4, p = .002), secondary patency (HR 7.2, p =. 07), and limb salvage (HR 7.8, p = .005) rates. Distal anastomosis to a tibial or foot vessel was also associated with lower primary patency (HR 4.8, p = .033), and primary assisted patency (HR 6, p = .011) rates. Use of a suprafascial tributary collateral as a graft was associated with lower primary patency (HR 6.7, p = .013), and primary assisted patency (HR 4.2, p = .042) rates.Conclusion: Vein diameter < 3 mm, distal anastomosis on a tibial or foot vessel, and use of a suprafascial tributary collateral as a graft were significantly associated with loss of patency and limb loss during follow up.