The importance of graft blood flow and peripheral outflow resistance for early patency in infrainguinal arterial reconstructions

Background: At present, the importance of functional parameters as determin ants for graft patency is under debate. Therefore, in our institution a pro spective study was undertaken to evaluate the influence of graft blood flow as well as the currently applied methods for outflow resistance measuremen t on early (less than or equal to 30 days) graft outcome. Patient and methods: 101 arterial revascularisations with infrageniculate g raft insertion were entered into this study. After having verified the morp hological integrity of the reconstruction, during temperature inflow occlus ion total outflow resistance (TOR) was determined as a pressure/flow relati onship by perfusion of the graft with saline (flow rates 25, 50, 100, 150 m l/min before and after papaverine) while simultaneously recording pressure generated at the distal anastomosis. In addition, after restoration of bloo d flow, flow index (FI) was calculated in an analogous way from the TBF thr ough the graft and the respective mean distal anastomotic pressure. Graft p atency at 30 days was determined by Duplex ultrasound. Results: Functional parameters were found to be unable to differentiate bet ween patent and failed reconstructions during the 30 day period: The mean T ORaveraged values amounted to 722.5 (SD = 310) in patent and 735.9 (SD = 22 8,1) mPRU in occluded by-passes (T-value = 0.1681; n.s.). The corresponding figures were 176.8 (SD = 91.2) and 196.4 (SD = 93.6) ml/min for TBF (T-val ue = 0.7342; n.s.) and were 0.53 (SD = 0.34) and 0.45 (SD = 0.25) PRU for F I (T-value = 0.8905; n.s.). Using multiple logistic regression analysis fun ctional parameters showed no influence oil graft patency while graft length and the necessity for intraoperative graft modification emerged to he sign ificant determinants of early graft outcome (R-2 adjusted = 0.46; p = 0006) . Conclusion: The results of our study suggest that neither blood flow nor th e presently used methods to assess outflow resistance are relevant prognost ic factors for early (less than or equal to 30 days) graft performance.