Occlusive vascular stapling in a canine inferior vena cava model

A canine model for inferior vena cava resection was devised to study the biomechanical and clinical applications of the cartridge stapler, which applies a triple staggered staple line. Eighteen mongrel dogs were subjected to subhepatic, suprarenal inferior vena cava occlusion with excision of the excluded segment. At 1 hour, six dogs were killed and inferior vena cava sizes and pressures were measured. All staple lines were intact. The inferior vena cava bursting pressure was 150 to 300 mm Hg. Ten dogs survived to 6 weeks and underwent repeat laparotomy with excision and measurement of the remaining inferior vena cava. Mean diameter was 1.9 cm. No evidence of staple line leakage was found despite chronic pressures to 39 cm H2O: median static bursting pressures were 250 mm Hg. Vein wall thickness of greater than 0.24 mm were all satisfactorily stapled. Histologic examination revealed normal reendothelialization, with improved healing at higher chronic pressures. No evidence of inflammation at the staple line or foreign body reaction was found. We conclude that a triple staple line provides secure, rapid venous occlusion that can withstand supraphysiologic stresses immediately and at 6 weeks.