Flow Waveform Analysis of Autologous Saphenous Vein Grafts for Reconstruction of Lower Extremity

Abstract

On the basis of the author's previous reports that the outcome of the recon structed lower extremity artery was closely associated with the electromagneti cally determined flow waveform pattern at operation and was an essential factor in determining the patency, the values of T variation—the integral of time differen tial of wall shear stress in one cardiac cycle for 35 consecutive femoropopliteal autologous saphenous vein grafts were reviewed by flow waveform analysis. For grafts with the Type O or I flow waveform pattern, the cumulative patency rate, calculated by the life-table method, was 94% at one and three years and 57% at five years. In contrast, for grafts with the Type II flow waveform pattern, the patency rate was 70% at one year, 43% at three and five years (p < 0.05, at one and three years). To assess the correlation between T variation values, and outcome of the grafts, 35 grafts were grouped into three, according to the value of T variation: grafts with T variation lower than 30 dyne/cm² , those with T variation ranging from 30 to 70 dyne/cm², and those with T variations higher than 70 dyne/cm ² . The grafts with T variation higher than 70 dyne/cm² showed the most favorable long-term patency and the grafts with T variation lower than 30 dyne/cm² showed poor results; the results were intermediate in grafts with a T variation ranging from 30 to 70 dyne/cm². Thus, flow waveform analysis is useful for predicting the outcome of femoropopliteal saphenous vein grafts. In particular, the T variation is a reliable indicator of the outcome of these grafts.