Follow-up of valves in saphenous vein bypass grafts with duplex ultrasonography

Abstract

Purpose: The objectives of this study were to describe the venous valves and determine their fate over time in reversed saphenous vein (RSV) and in situ saphenous vein (ISV) bypass grafts with duplex ultrasonography. Methods: Sixty-four patients contributed 50 RSV and 19 ISV infrainguinal vein grafts. Forty-two of the RSVs and 17 of the ISVs had valves or valve remnants. The grafts and valves were studied serially with duplex ultrasonography to document the location, characteristics, and changes with time. The valve leaflets visualized by means of ultrasonic duplex scanning were described as moving, frozen, remnant of a cusp, or "functioning." In addition, the presence of a valve sinus and thickening of the wall at the site were documented. Grafts were studied at 1, 2, 3, 4, 6, 9, 12, and 18 months and then annually. Results: In 42 RSV grafts (84%) and 17 ISV grafts (89.5%), 200 valves were identified. Only five of the 200 valves (2.5%) required intervention because of a velocity ratio (VR) of 3.5 or greater. Eight (42.1%) of the 19 ISV grafts needed 15 revisions, and 18 (36%) of the 50 RSV grafts required 30 revisions. The five revisions for a stenotic valve occurred only in RSV grafts. From the 30 revisions in the RSV grafts, only 16.7% (5 of 30) were for a valve-related stenosis. The average follow-up period for a valve from the time of detection was 16.1 ± 9.6 months. Ten of the 17 (58.8%) valve-associated stenoses (VR > 2.5) showed a regression to a VR less than 2.0 within a mean time of 3.1 months (range, 1.5-4.5 months). A progression of the valve-associated lesion from a VR less than 2.0 to a VR higher than 3.5 occurred in only one case within a period of 3.5 months. Conclusion: The described features of valves in saphenous vein grafts are common and can be identified by means of duplex sonography. Only 16.7% of the revisions in RSV grafts were performed because of a valve-related stenosis, and none of the revisions in ISV grafts were performed because of a valve lesion. Lesions associated with a valve may regress in time. No specific valve features could be identified as "high" risk for graft failure.