In situ saphenous vein bypass (ISSV) techniques are preferable when the "ta
rget vessel" for arterial reconstruction is below the knee. There is no min
imally acceptable vein; however, it must be large enough to generate a phys
iologic increase in ankle pressure following bypass. This retrospective cha
rt review sought to determine success rates for limb salvage and long-term
graft patency in individuals with "less than optimal" saphenous veins. Over
a 24-month period, 76 below-the-knee ISSV bypasses were performed and 17 v
eins were described as "suboptimal." Of those, three had evidence of prior
thrombophlebitis, one had severe varicose changes throughout the graft leng
th, and two were too small to be used for reconstruction. Of the 11 small s
aphenous veins used, the smallest diameter measured after establishment of
arterial flow ranged from 0.9 to 1.6 mm (mean=1.2). Target vessels included
the below-the-knee popliteal artery (n=one), posterior tibial artery (n=tw
o), peroneal artery (n=four), anterior tibial artery (n=two), and the dorsa
lis pedis artery (n=two). Following arterial anastomosis, a 15% or greater
increase in ankle-brachial index was achieved in all cases. Limb salvage wa
s achieved in eight of 10 limbs. However, amputation was required in three
patients and one died secondary to chronic renal failure. Follow-up ranged
from 3 to 24 months (mean=13). Four bypasses thrombosed despite aggressive
surveillance, two had multisegmental graft stenoses requiring revision, and
five remained patent (mean follow-up: 9.6 months). Short-term patency was
satisfactory and immediate limb salvage was achieved. However, long-term li
mb salvage was not improved. On the basis of these results, the authors wou
ld not recommend the use of saphenous veins less than 2 mm minimum diameter
for ISSV bypass.