Morphological features of blood access stenosis and results of noninvasive angioplasty. We investigated a connection between the results of noninvasive angioplasty for the blood access stenosis and its morphological features in 37 dialysis cases. In 3 cases presenting stenosis in the original artery, the area could not be dilated by noninvasive techniques. In 4 cases with stenosis in the arterialized vein downstream of the needle insertion points for extracorporeal circulation, 3 showed long-term dilatation by the procedures. In 30 cases having stenosis upstream of the points, 16 showed long-term dilatation. In the unsuccessful cases, the angle formed between the axes of the stenosed portion and the normal vessel was over 39 degrees, and the distance between the anastomosis and the stenosed portion was less than 11 mm. 