Venous hemodynamics in a chronic venous valvular insufficiency model. To develop a large-animal model of chronic venous valve incompetence, 13 greyhound dogs underwent unilateral hindlimb venous valve lysis with a valve cutter apparatus pulled retrograde through the iliac, femoral, and lateral saphenous veins. Bilateral venous pressures in the lateral saphenous vein were recorded before valve lysis, immediately after valve lysis, and at intervals from 1 to 14 weeks after valve lysis, with the dogs in the supine position and elevated 80 degrees semierect, as well as after stimulated hindlimb muscle contraction to empty the hindlimb veins. Passive venous filling time with elevation and 90% venous refilling time after muscle contraction were calculated. From immediately after through 14 weeks after valve lysis, a shortened venous filling time and 90% venous refilling time as well as an elevated poststimulation venous pressure were noted. This valve lysis method successfully produced a hemodynamically verified model of venous valvular insufficiency. 