Intravascular ultrasound imaging before and after angioplasty for stenosis of arteriovenous fistulae in haemodialysis patients

Background. Complications of haemodialysis vascular access have emerged as a major cause of patient morbidity. Intravascular ultrasound imaging is a new technical modality providing visualization of the Vessel lumen and wall structure in a cross-sectional fashion. Percutaneous transluminal angioplasty has long been used in the treatment of stenoses of arteriovenous fistulae. However, there is no detailed quantitative information on the stenotic lesion and the morphological change by angioplasty. Methods; Intravascular ultrasound studies were performed in 40 haemodialysis patients with 63 stenoses in arteriovenous fistulae who had percutaneous transluminal angioplasty. The patients were qualitatively and quantitatively evaluated for echogenic patterns and morphological changes before and after angioplasty. Results. Morphological plaque features in stenotic lesions were classified as 37 soft (58%), five hard (8%), 20 mixed (32%), and one calcified sites. Plaque fractures after angioplasty were detected in 45/63 (71%) instances. The lumen cross-sectional area was found to be dilated approximately threefold (from 3.8 +/- 2.4 to 11.1 +/- 4.5 mm(2)) and the external elastic membrane cross-sectional area was dilated approximately twofold (from 11.1 +/- 5.3 to 19.8 +/- 8.1 mm(2)) after angioplasty. Conclusion. These results indicate that intravascular-ultrasound allows both qualitative and quantitative assessments of arteriovenous fistulae in haemodialysis patients. The results further suggest that the mechanism of expansion of arteriovenous fistulae stenoses by percutaneous transluminal angioplasty involves stretching of the vessel wall as well as plaque fractures.