Revascularization of swine renal artery stenosis improves renal function but not the changes in vascular structure

Renal revascularization by percutaneous transluminal angioplasty improves blood pressure and stenotic kidney function in selected groups of patients, but the reversibility of intrarenal and microvascular remodeling remains unknown. Here, we tested the hypothesis that renal angioplasty improves the function and structure of renal microcirculation in experimental chronic renal artery stenosis. Stenotic kidney function, hemodynamics, and endothelial function were assessed in vivo in pigs after 10 weeks of unilateral renal artery stenosis. Renal microvascular remodeling, angiogenic pathways, and fibrosis were measured ex vivo. Angioplasty and stenting carried out 4 weeks before measurement decreased blood pressure, improved glomerular filtration rate, and improved microvascular endothelial function. It also promoted the expression of angiogenic factors and decreased renal apoptosis due to stenosis, compared with a sham intervention. The spatial density of renal microvessels, however, was partially improved after angioplasty. Renal blood flow was incompletely restored compared with the kidneys of sham-treated animals, as was interstitial fibrosis. Renal microvascular media-to-lumen ratio remained unchanged by angioplasty. Thus, our study shows that revascularization of a stenotic renal artery restores the glomerular filtration rate and renal endothelial function 4 weeks later. Renal hemodynamics and structure, however, are incompletely resolved.