Increased blood loss with in situ bypass.

This study uses perioperative hematocrit determinations to quantitatively evaluate blood loss in patients undergoing either in situ (n = 37) or reverse vein technique (n = 44) for femorodistal popliteal or proximal tibial/peroneal reconstruction. The median drop in hematocrit was significantly greater on the fourth postoperative day in the in situ group as compared with the reverse vein group. The median drop in hematocrit was 8.8 +/- 4.2 per cent in the in situ group as compared with 4.8 +/- 4.1 per cent in the reverse vein group (P less than 0.0005). Blood transfusions were required in 11 of 37 patients (30%) in the in situ group as compared with five of 44 patients (11%) in the reverse vein group (P less than 0.05). Despite limitations of a retrospective study, our data indicate that there is greater blood loss with in situ technique as compared with reverse vein technique for femoropopliteal and crural reconstruction.