Carlos P. Cruz

Vein diameter measurements using B-mode Doppler ultrasound (US) are used to assess the greater saphenous vein (GSV) for bypass operations; a 2.5–3.0 mm diameter is suggested as a minimum. Preoperative measurements are made while the vein is in the low-pressure venous system. This may not reflect the distended diameter of a vein after placement in the arterial system. This study compares preoperative and postoperative GSV diameters to identify the degree of dilatation and the minimal size adequate for use in arterial bypass operations. The GSV of 11 patients undergoing an infrainguinal arterial bypass were assessed by utilizing Doppler US. Measurements were taken every 10 cm, for 70 cm, along the course of the GSV before and 4 weeks after operation. All segments showed a percent increase in diameter from the preoperative to postoperative time points; 10 cm, 38%; 20 cm, 31%; 30 cm, 16%; 40 cm, 26%; 50 cm, 23%; 60 cm, 28%; and 70 cm, 22%. A Bonferroni post hoc analysis between the 2 time point means showed a significant increase in means for the 2 time points of 9.49 units (Bonf p value 4.1 mm. All showed a significant increase over time. Preoperative diameter measurements of the vein may not reflect the final distended diameter after bypass. Preoperative vein diameters =3.0 mm showed a significant increase of 33% to nearly 4.0 mm. This was the largest increase observed in any segment measured. A potential 16–33% increase in vein diameter should be considered in vein mapping. The rejection of small veins (=3.0 mm) in preoperative vein-mapping studies may not be warranted given the potential for a substantial increase in size when placed in the arterial system.