Injury potential to venous valves from the Amplatz thrombectomy device

PURPOSE: To evaluate the acute effects of the Amplatz thrombectomy device ( ATD) on peripheral venous valves in a canine model. MATERIALS AND METHODS: ATD thrombectomy was performed in 17 veins, and cont rol experiments with use of an 8-F sheath-dilator were performed in four ve ins. Prethrombectomy ascending venography was performed, followed by device passage across the vein segment. Post-thrombectomy ascending venography wa s then performed, followed by heparinization and euthanasia. The treated ve ins were carefully explanted and stored in formaldehyde for histopathologic examination. Severity of valve injury was graded on a scale of 0 to 4. RESULTS: In ATD-treated veins: 10 veins sustained no injury [grade 0] (diam eter, 6.7 mm +/- 1.7; antegrade/retrograde approach, 5/5), five veins susta ined mild injury [grade 1-2] (diameter, 5.2 mm +/- 0.8; antegrade/retrograd e, 3/2), while the remaining two veins sustained moderate-to-severe injury [grade 3-4] (diameter, 5 and 6 mm; antegrade/retrograde, 1/1), In sheath-di lator treated veins: no injury [grade 0] in any of the four treated veins ( mean diameter, 5.5 mm +/- 0.6; all retrograde). In ATD-treated veins, valve injury (of any grade) was significantly more frequent in veins 6 mm or les s in diameter than in veins at least 7 mm in diameter (seven of 12 vs zero of five; P <.03), There was no significant association between thrombectomy approach and injury grade. CONCLUSION: Veins 7 mm or greater in diameter were associated with no signi ficant valve injury during ATD thrombectomy, However, long-term and short-t erm effects on valvular function will need to be assessed.