Transluminal dilatation of experimental hydronephrosis in dogs: acute and chronic effects, haemodynamic changes, and histological findings.

In the present study the feasibility and effectiveness of transureteral dilatation with a double-lumen balloon-tipped dilatation catheter was investigated. In 6 dogs with experimentally induced unilateral fibrotic stenosis and hydronephrosis a total of 13 dilatations were performed through a cutaneous ureteroneostomy. The stenosis diameter could markedly be distended from 1.7 +/- 0.9 to 4.8 +/- 1.6 mm (p less than 0.001). The pyelon size changed not significantly during the intervention. Follow-up urographies 1 week after dilatation revealed partial or total restenosis in all but 2 dogs. The stenosis diameter had decreased by 2.6 +/- 1.5 mm (p less than 0.01). The mean pyelon size changed only slightly (28.2 +/- 14.7 vs. 26.1 +/- 6.2 cm2). In the 2 dogs with persistent distension of the stenosis a reduction in pyelon size was achieved. Blood pressure during acute ureteral ligation showed no change. Follow-up studies after 1 week revealed a significant fall of the mean arterial pressure from 100 +/- 22 to 83 +/- 19 mm Hg (p less than 0.005), which was also seen at the long-term follow-up in 5 dogs 13 +/- 8 weeks after ureteral ligation. Histological analysis showed mild to severe inflammation and distension of the collecting system and mild to moderate inflammation, atrophy, and glomerular cysts in the renal parenchyma. Interestingly, the 2 dogs with a successful result of dilatation showed no relevant inflammation in the dilated stenotic segment. In conclusion, transureteral dilatation of experimental ureteral stenosis with a balloon catheter proved to have an impressive acute effect.(ABSTRACT TRUNCATED AT 250 WORDS)