PREOPERATIVE DUPLEX VENOUS MAPPING - A COMPARISON OF POSITIONAL TECHNIQUES IN PATIENTS WITH AND WITHOUT ATHEROSCLEROSIS

Purpose: Preoperative duplex venous mapping is the preferred modality to measure the diameter of the greater saphenous vein and its suitabil ity as an arterial conduit for infrainguinal bypass. We wanted to dete rmine the optimal mapping technique and maximal venous diameter in pat ients with and without atherosclerosis. Methods: Three groups of patie nts were prospectively studied: younger control subjects (n = 20), pre operative atherosclerotic patients (n = 10), and older control subject s (n = 10). Ah patients underwent greater saphenous vein duplex mappin g in a standardized manner. Maximal internal vein diameters were measu red with the subjects in the supine position in bed, in the 20 degree reversed Trendelenburg position, sitting on the edge of the bed, stand ing, and in the supine position with a high-thigh, low-pressure tourni quet. Measurements were taken just beyond the saphenofemoral junction, in the distal thigh, below the knee, at midcalf, and superior to the medial malleolus. Results: In younger control subjects an increasingly more erect position resulted in progressively larger measured vein di ameters at all levels along the length of the leg. Both patients with atherosclerosis and older control subjects had no such increase in ven ous diameter with any positional change from the supine position to st anding. Patients with atherosclerosis also had significantly smaller m easured veins than either younger or older control subjects. A high-th igh tourniquet significantly increased vein diameters in the atheroscl erotic group to the size of vein diameters in the older control group, although the absolute size differences were not large. Conclusions: T he optimal position for venous mapping is with the patient in a supine position. If the internal vein diameter is below an acceptable minimu m size, a high-thigh tourniquet will maximally distend the vein in pat ients with atherosclerosis. Vein diameter decreases with age and is le ss distended in patients with atherosclerosis compared with older pati ents without atherosclerosis.