Correlation between angiographic runoff and intraoperative hydraulic impedance with regard to graft patency

The aim of this study was to evaluate the correlation between peripheral runoff estimated by the SVS/ISCVS scoring system and intraoperatively measured outflow. Sixty-six patients received 27 femoropopliteal and 39 femorocrural ePTFE grafts. During the operation, peripheral resistance and hydraulic impedance were measured by means of the extracorporeal-bypass-flow method. Angiographic runoff was estimated according to the revised SVS/ISCVS system. Patients were entered in a graft surveillance program and patency was calculated after 3 years. The relation between the angiographic runoff score and graft patency as well as correlations between hemodynamic data, peripheral resistance, and hydraulic impedance were calculated. Primary and secondary patency rates for femoropopliteal grafts were 44% and 60% and those for femorocrural bypasses were 35% and 45%. Mean angiographic vessel diameters for above-knee and below-knee popliteal arteries were 0.51 +/- 0.02 mm and 0.47 +/- 0.04 mm. Diameters of crural arteries were 0.34 +/- 0.03 mm (posterior tibial artery), 0.27 +/- 0.02 mm (anterior tibial artery) and 0.26 +/- 0.21 mm (peroneal artery). The differences in diameter between popliteal and crural grafts were statistically significant (p < 0.01). Calculated correlations between the pre-operative score and hemodynamic, resistance, and impedance values or patency rates were generally poor and statistically not significant. A statistical significant correlation was found only between SVS/ISCVS score and recipient vessel diameters. The angiographic runoff did not correlate with peripheral resistance, impedance, or patency rates. Patients with angiographically poor outflow should additionally be evaluated with duplex sonography or magnetic resonance angiography and should not be denied peripheral reconstructions.