Atherosclerotic renal artery stenosis and revascularization

Renal artery revascularization using the inferior mesenteric artery as an inflow source with a long-term follow-up

This case describes a 72-year-old woman with a history of chronic kidney disease stage III presented with bilateral renal artery stenosis with a progressively atrophied right kidney. At the time of surgery, the atrophied kidney was nonfunctional. Therefore, the patient underwent unilateral renal artery revascularization via the inferior mesenteric artery as an inflow. A 7-year follow-up revealed improvement in the kidney function and stabilization of blood pressure, which was controlled with less number of antihypertensive medications. In brief, open surgical correction of the renal artery stenosis using the inferior mesenteric artery as an inflow source can retrieve renal function in selected hypertensive patients with ischemic nephropathy.

Systemic biopolymer-delivered vascular endothelial growth factor promotes therapeutic angiogenesis in experimental renovascular disease

We recently developed a therapeutic biopolymer composed of an elastin-like polypeptide (ELP) fused to vascular endothelial growth factor (VEGF) and showed long-term renoprotective effects in experimental renovascular disease after a single intra-renal administration. Here, we sought to determine the specificity, safety, efficacy, and mechanisms of renoprotection of ELP-VEGF after systemic therapy in renovascular disease. We tested whether kidney selectivity of the ELP carrier would reduce off-target binding of VEGF in other organs. In vivo bio-distribution after systemic administration of ELP-VEGF in swine was determined in kidneys, liver, spleen, and heart. Stenotic-kidney renal blood flow and glomerular filtration rate were quantified in vivo using multi-detector computed tomography (CT) after six weeks of renovascular disease, then treated with a single intravenous dose of ELP-VEGF or placebo and observed for four weeks. CT studies were then repeated and the pigs euthanized. Ex vivo studies quantified renal microvascular density (micro-CT) and fibrosis. Kidneys, liver, spleen, and heart were excised to quantify the expression of angiogenic mediators and markers of progenitor cells. ELP-VEGF accumulated predominantly in the kidney and stimulated renal blood flow, glomerular filtration rate, improved cortical microvascular density, and renal fibrosis, and was accompanied by enhanced renal expression of VEGF, downstream mediators of VEGF signaling, and markers of progenitor cells compared to placebo. Expression of angiogenic factors in liver, spleen, and heart were not different compared to placebo-control. Thus, ELP efficiently directs VEGF to the kidney after systemic administration and induces long-term renoprotection without off-target effects, supporting the feasibility and safety of renal therapeutic angiogenesis via systemic administration of a novel kidney-specific bioengineered compound.

[Renovascular disease in children - a rare diagnosis with few symptoms]

BACKGROUND To estimate the prevalence, symptoms, causes and treatment of renovascular disease in children, and also to assess the degree of secondary organ damage to the heart, kidneys and eyes (end organ damage).MATERIAL AND METHOD Retrospective review of data for all children (0 - 16 years) who were examined for resistant hypertension in the period 1998 - 2013 at Oslo University Hospital Rikshospitalet.RESULTS A total of 21 children/adolescents (median age 8.5 years, 11 girls) were assessed and treated for resistant hypertension in the study period. Altogether had 38 % no symptoms at the time of diagnosis and 19 % had classical symptoms of hypertension. Fifteen patients received invasive treatment in the form of percutaneous transluminal renal angioplasty (PTRA) (n = 5), nephrectomy (n = 6), coiling (n = 1), autotransplantation (n = 1) or a combination of these (n = 2). Blood pressure improved following treatment in 10 of 14 patients for whom outcomes were recorded in the medical records. End organ damage to the heart and retina was observed in 60 % and 50 % of patients, respectively.INTERPRETATION Children with severely elevated blood pressure as a result of renovascular disease often have unspecific or no symptoms. Blood pressure improved following invasive treatment in 10 of 14 children and few complications were recorded. Invasive treatment may be considered in children and adolescents when standard treatment for hypertension is insufficient.

Multimarker assessment for the prediction of renal function improvement after percutaneous revascularization for renal artery stenosis

BACKGROUND

Identifying patients likely to have improved renal function after percutaneous transluminal renal angioplasty and stenting (PTRA) for renal artery stenosis (RAS) is challenging. The purpose of this study was to use a comprehensive multimarker assessment to identify those patients who would benefit most from correction of RAS.

METHODS

In 127 patients with RAS and decreased renal function and/or hypertension referred for PTRA, quantification of hemodynamic cardiac stress using B-type natriuretic peptide (BNP), renal function using estimated glomerular filtration rate (eGFR), parenchymal renal damage using resistance index (RI), and systemic inflammation using C-reactive protein (CRP) were performed before intervention.

RESULTS

Predefined renal function improvement (increase in eGFR ≥10%) at 6 months occurred in 37% of patients. Prognostic accuracy as quantified by the area under the receiver-operating characteristics curve for the ability of BNP, eGFR, RI and CRP to predict renal function improvement were 0.59 (95% CI, 0.48-0.70), 0.71 (95% CI, 0.61-0.81), 0.52 (95% CI, 0.41-0.65), and 0.56 (95% CI, 0.44-0.68), respectively. None of the possible combinations increased the accuracy provided by eGFR (lower eGFR indicated a higher likelihood for eGFR improvement after PTRA, P=ns for all). In the subgroup of 56 patients with pre-interventional eGFR <60 mL/min/1.73 m(2), similar findings were obtained.

CONCLUSIONS

Quantification of renal function, but not any other pathophysiologic signal, provides at least moderate accuracy in the identification of patients with RAS in whom PTRA will improve renal function.