The role of pararenal collaterals in assessing renal artery stenosis before and after percutaneous transluminal angioplasty.

For the past several years, observation of flow direction in non-parenchymal renal artery branches, particularly during pharmacoangiography, has proved to be extremely reliable in the preoperative evaluation of the hemodynamic significance of renal artery stenoses. The advent of percutaneous transluminal angioplasty (PTA) has expanded the applications for these methods. Their value in PTA is demonstrated through five illustrative cases. In four stenoses shown to be significant before PTA, clinical responses were favorable. In one case undergoing PTA of an anatomically severe, but hemodynamically insignificant stenosis, blood pressure was unchanged after PTA. After PTA, observation of orthograde flow in the pararenal arteries confirms the adequacy of the procedure, and predicates a favorable clinical response.