Iloprost reduces peripheral resistance during femoro-distal reconstruction.

A randomised placebo-controlled trial was conducted to investigate the effect of iloprost, a stable prostacyclin mimetic, on peripheral resistance during femoro-distal bypass. Patients undergoing femoro-distal long saphenous vein bypass for critical ischaemia received 3000 ng of iloprost or placebo infused into the graft via an unligated side branch over 2 min. Graft blood flow and peripheral resistance were measured for 20 min, using an operative Doppler flowmeter (OpDop 130, SciMed, U.K.) and a pressure transducer to record graft pressure. Postoperatively, graft blood flow was assessed by daily duplex ultrasound for 7 days. Iloprost produced an immediate drop in peripheral resistance in all cases (n = 18) by a mean (range) of 40% (4-80%) compared with controls (n = 15) in whom there was a 5.3% (-8 to +36%) increase in resistance (p less than 0.01, Wilcoxon test). Decreased peripheral resistance in iloprost-treated patients persisted to 20 min. The largest decreases in peripheral resistance occurred in patients with the highest initial resistances (r = 0.56, p less than 0.02). Graft flow during the same period increased by 52% (-7 to 294%) compared with controls in whom there was a 6% (-17 to 26%) increase in flow, (p less than 0.01). Flow remained elevated by 53% over baseline values at 1 week post-infusion in the iloprost-treated group but this did not achieve statistical significance compared to controls in whom flow also increased by 13%. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.