Graft stenosis: justification for 1-year surveillance. In all, 412 femorodistal grafts (femoropopliteal and femorocrural), performed between 1984 and 1988, have been prospectively studied at 6 weeks and 3, 6, 9 and 12 months after operation and at intervals of 6 months thereafter by duplex scanning and intravenous digital subtraction angiography. The overall incidence of stenoses was 16 per cent (femorocrural 20 per cent, femoropopliteal 15 per cent). All stenoses were detected in the first year after operation and none occurred after this. Twenty-four non-haemodynamically significant stenoses were not treated but were followed at intervals of 3 months. Forty-two haemodynamically significant stenoses were detected and secondary procedures were performed in 30 grafts at a mean of 8 months after surgery. Thirteen had percutaneous balloon dilatation and six (46 per cent) remain patent at a mean follow-up of 22 months. Two grafts which occluded within 30 days and three which restenosed at a mean of 8 months had tertiary procedures. Seventeen grafts were surgically revised, nine with patch grafts and eight with bypass grafts. Eleven of these remain patent at a mean follow-up of 30 months. One occluded immediately and three occluded late. Two grafts which restenosed at a mean of 19 months had successful tertiary procedures. In total, seven grafts had tertiary procedures (two had balloon dilatation and five had surgery) and six of these remain patent at a mean follow-up of 13.5 months. In conclusion, 37 procedures have been performed on 30 grafts, of which 23 (77 per cent) remain patent at a mean follow-up of 12 months. Approximately one-quarter of femorodistal grafts will develop graft-related stenoses and graft surveillance is worthwhile, but only for the first year after operation. 