Die Bedeutung des Flußvolumens sowie des peripheren Abflußwiderstandes für die Frühfunktion von infrainguinalen arteriellen Rekonstruktionen

Abstract

Background: At present, the importance of functional parameters as determinants for graft patency is under debate. Therefore, in our institution a prospective study was undertaken to evaluate the influence of graft blood flow as well as the currently applied methods for outflow resistance measurement on early (≤ 30 days) graft outcome. Patient and methods: 101 arterial revascularisations with infrageniculate graft insertion were entered into this study. After having verified the morphological integrity of the reconstruction, during temporary inflow occlusion total outflow resistance (TOR) was determined as a pressure/flow relationship by perfusion of the graft with saline (flow rates 25, 50, 100, 150 ml/min before and after papaverine) while simultaneously recording pressure generated at the distal anastomosis. In addition, after restoration of blood flow, flow index (FI) was calculated in an analogous way from the TBF through the graft and the respective mean distal anastomotic pressure. Graft patency at 30 days was determined by Duplex ultrasound. Results: Functional parameters were found to be unable to differentiate between patent and failed reconstructions during the 30 day period: The mean TORaveraged values amounted to 722.5 (SD = 310) in patent and 735.9 (SD = 228,1 ) mPRU in occluded bypasses (T-value = 0.1681; n.s.). The corresponding figures were 176.8 (SD = 94.2) and 196.4 (SD = 93.6) ml/min for TBF (T-value = 0.7342; n.s.) and were 0.53 (SD = 0.34) and 0.45 (SD = 0.25 ) PRU for FI (T-value = 0.8905; n.s.). Using multiple logistic regression analysis functional parameters showed no influence on graft patency while graft length and the necessity for intraoperative graft modification emerged to be significant determinants of early graft outcome (R2 adjusted = 0.46; p = 0.006). Conclusion: The results of our study suggest that neither blood flow nor the presently used methods to assess outflow resistance are relevant prognostic factors for early (≤ 30 days) graft performance.