Evaluating the outcome of percutaneous transluminal angioplasty in renal graft artery stenosis using the areas under the time curve of glomerular filtration rate and blood pressure

The benefit of percutaneous transluminal angioplasty (PTA) of transplant renal artery stenosis for ischemic nephropathy may be adversely affected by rejection or other complications. As a result, assessment of the effect of PTA on renal function or blood pressure is often difficult. In this paper, we evaluated the effect of PTA using the method of integrated glomerular filtration rate (GFR) based upon the area under the curve over a follow-up period (AUC0-1), to express the level of GFR in a simple manner despite its significant fluctuations. A similar procedure was used to evaluate mean arterial pressure (MAP). The method was employed to assess the outcome in 20 individuals before PTA, and 1, 3, 6, 9 and 12 months after PTA. In eight cases, rejection was detected while there was one case of glomerulonephritis in the graft during the follow-up period. Evaluation (AUCCcr)0-12 related to the integrated pre-PTA value of Ccr [(Ccr)0 x 12] revealed a rise in GFR by more than 20 % in 65 % of cases. No improvement was observed in seven individuals with post-PTA complications. When assessing the integrated value of MAP, success of PTA (a reduction by at least 10 %) was found in 85 % of cases. No significant correlation was found between the relative changes of integrated GFR and MAP. Our data suggest that evaluation of the integrated value of GFR or MAP on the basis of AUC0-t allows to characterize, in a simple manner, the level of graft function and MAP throughout the follow-up period in individual cases. Furthermore, it may provide additional information on the average values obtained at different time intervals after the therapeutic procedure.