Mechanisms of angioplasty in hemodialysis fistula stenoses evaluated by intravascular ultrasound

Abstract

Mechanisms of angioplasty in hemodialysis fistula stenoses evaluated by travascular ultrasound. Quantification of luminal dimensions and the mechanisms by which angioplasty (PTA) corrects non-atheroma venous stula stenoses have been poorly studied. In 38 consecutive percutaeous balloon angioplasties of hemodialysis fistula stenoses, catheterbased, mechanically-rotated intravascular ultrasound (IVUS) images were obtained along with cineangiography. Images from 24 brachial vein, 11 central vein, 2 graft anastomoses, and 1 brachial artery were quantitatively and qualitatively evaluated. Semiautomated quantitative angiographic stenosis was 64 ± 13% pre-PTA and reduced to 36 ± 19% post-PTA (P < 0.001). Post-PTA IVUS minimal lesion diameter and cross sectional area were 5.7 ± 1.5 mm and 2.9 ± 1.5 mm2, respectively. With IVUS, mechanisms observed were: vessel dissection in 16 42%), arterial stretch (defined as vessel diameter : balloon diameter raotio = 0.75 to 1.0) in 19 (50%), and elastic recoil (defined as vessel diameter : balloon diameter ratio < 0.75) in 19 (50%). Compared to angiography, morphologic information provided by IVUS were plaque composition (hard 11%, soft 89%), plaque topography (eccentric 94%, concentric 6%), thrombus (IVUS: N = 6 vs. angio: N = 1), dissection IVUS: N = 16 vs. angio: N = 1). Thus, IVUS can evaluate lesion morphology and define luminal dimensions after angioplasty. Mechamisms of successful angioplasty of hemodialysis fistula stenosis occur primarily by vessel stretching and dissection, and significant post-PTA narrowing is due to elastic recoil.