Early detection of stenosis of femoro-distal grafts. A surveillance study using colour-duplex scanning.

The development of stenoses following femoro-distal bypass procedures may jeopardise graft function. In a prospective study serial assessment of femoro-distal grafts in 77 patients was performed over a period of 13 months. Forty-eight of the bypasses were in situ, 18 were reversed veingrafts and 11 were modified sheep collagen grafts. Colour coded duplex scanning of all grafts was performed in addition to physical examination, ankle systolic pressure measurements and pulse volume recordings. Stenotic areas were detected in the graft in 16 cases and at the site of the proximal anastomosis in one case. In one graft a residual valve leaflet was found. In addition eleven arterio-venous communications were observed in in situ veingrafts and one aneurysmal degeneration in a collagen graft was noted. All stenoses were detected by colour duplex scanning and confirmed by arteriography or operative exploration. Only 38% of the stenoses over 50% was associated with recurrent symptoms or could be detected by diminished palpable pulses. Ankle blood-pressure measurements and pulse volume recordings indicated the presence of a stenosis over 50% in only 46% of the cases. Twelve of 13 patients with graft stenosis over 50% were revised by vein patch plasty with a good result in all cases. The primary and secondary two year cumulative patency rates of all in situ bypasses were 63% and 79% respectively. Close surveillance of femoro-distal grafts appears justified by this study. Colour duplex scanning was superior to systolic ankle pressure measurements and pulse volume recording in detecting the development of graft stenosis.