Arterial reconstructions of the lower extremities were reviewed to assess the usefulness of flow waveform analysis. Six hundred and thirty-four arterial reconstructions were divided into two groups: a former (1965-1973) group of 218 reconstructions not assessed by flow waveform analysis and a recent (1974-1985) group of 416 reconstructions analyzed according to flow waveform. The cumulative patency rates of the former and the recent group at 5 years were as follows: aorto-femoral, 75.2% and 86.7% (P less than 0.05); femoral-distal, 34.6% and 61.5% (P less than 0.001); extra-anatomical, 63.6% and 80.2% (P = 0.06), respectively. Based on the various flow waveforms evidenced intraoperatively, the cumulative patency rate of cases in the recent group with type 0 and I flow waveform was compared to the rate of those with type II flow waveform. The cumulative patency rates at 5 years were as follows: aorto-femoral, 92% and 82.7% (P = 0.15); femoral-distal, 77.7% and 49.3% (P less than 0.001); extra-anatomical, 91.8% and 68.9% (P less than 0.05), respectively. These results indicate that intraoperative flow waveform analysis is a simple and useful indicator for predicting the long-term results of arterial reconstruction.