Relationship between hemodynamic parameters of renal artery stenosis and the changes of kidney function after renal artery stenting in patients with hypertension and preserved renal function.

ABSTRACT

INTRODUCTION: The role of physiological assessment of renal artery stenosis (RAS) using renal fractional flow reserve (rFFR) and resting translesional pressures ratio (Pd/Pa ratio) in the prediction of benefit from revascularization is still unknown. OBJECTIVES: The aim of the study was to assess the relationship between hemodynamic data and the change in kidney function after renal artery stenting in secondary hypertension. PATIENTS AND METHODS: 34 hypertensive patients (50% males, median age 65 years) with at least 60% RAS, underwent stenting and were followed up for 6 months. Pd/Pa ratio (ratio of mean distal to lesion to proximal pressure) and hyperemic rFFR (after papaverine) were measured before the procedure. At baseline and after 6 months, the glomerular filtration rate (eGFR), serum cystatin C and albuminuria were determined. In receiver operating characteristic curves, two previously established cut-off values with the highest accuracy of identifying severe RAS were used 0.93 for the Pd/Pa ratio and 0.8 for the rFFR. RESULTS: No significant difference in eGFR was found between patients with decreased and normal Pd/Pa ratio (1.4 vs 7.9 ml/min, p = ns). Similarly, minor changes in eGFR were observed in patients with decreased vs normal rFFR (2.4 vs 4.1 ml/min, p = ns). In patients with decreased Pd/Pa ratio, albuminuria remained stable (change 1.4 mg/24 h) compared with an increase of 12.6 mg/24 h in the subgroup with Pd/Pa ≥ 0.93(p < 0.05). However, after exclusion of two outliers with significant baseline proteinuria (425 and 1095 mg/24 h, respectively), the difference in albuminuria change according to the baseline Pd/Pa ratio was no longer maintained. CONCLUSIONS: Hemodynamic parameters of RAS do not distinguish the patients who may benefit from renal artery stenting in terms of kidney function improvement in short-term follow-up.