Importance of Flow Waveform and Flow Volume as Prognostic Indicators for the Patency of Infra-Inguinal Autologous Vein Bypass

Abstract

To investigate the association of the intraoperative flow waveform and the flow volume with the graft prognosis of infrainguinal vein bypass. Retrospective study. Intraoperative flowmetry was performed for infrainguinal autologous vein bypass between 2011 and 2020. Flow waveforms were classified into type 0-IV according to the Kyushu University (KU) classification. The patients (n=340) were divided into three groups based on the flow waveform predicting the graft patency: type 0/I (long patency), type II (no early occlusion but late occlusion possible) and type III/IV (early occlusion). The graft occlusion rates of popliteal artery bypass (PAB) and infrapopliteal artery bypass (IPAB) within 30 days after surgery were compared between type 0/I+II and type III/IV groups, while the mid-term graft patency rates were compared between type 0/I and type II groups. Additionally, a multivariate analysis was performed to identify independent risk factors for early and late graft occlusion. The early graft occlusion rates of type 0/I+II and type III/IV groups were 3.9 % and 0%, respectively, (p=1.00) for PAB and 5.3 % and 46.2% respectively, (p<.001) for IPAB. The 2 years' primary patency rates of type 0/I and type II groups were 91% and 75%, respectively, (p= .030) for PAB and 58% and 63%, respectively, (p= .72) for IPAB. An independent risk factor for early occlusion was none in PAB and flow waveform (type IV) in IPAB. An independent risk factor in PAB was flow waveform (type II), end-stage renal disease, and dual antiplatelet use and those in IPAB were older age, female sex, lower flow volume, and iterative bypass for primary patency loss. Intraoperative flowmetry is useful for predicting the graft prognosis in infrainguinal vein bypass and its significance depends on the distal target artery.