Ching M. Cheung

Measurement of single kidney function using dynamic contrast-enhanced MRI: comparison of two models in human subjects.

To compare two methods for assessing the single kidney glomerular filtration rate (SK‐GFR) in humans using dynamic contrast‐enhanced (DCE)‐MRI.

The Effects of Statins on the Progression of Atherosclerotic Renovascular Disease

Background/Aims: The aim was to examine the influence of statin therapy on the natural history of atherosclerotic renal artery stenosis (RAS). Methods: Our hospital atherosclerotic renovascular disease (ARVD) database was analysed for patients who underwent repeat renal angiography during clinical follow-up. Patients with ≧1 RAS lesion and ≧4 months between baseline and repeat renal angiography were analysed. 79 patients were included. Baseline renal arterial anatomy was classified as normal, ≤50% RAS, >50% RAS or renal artery occlusion. Results: Mean follow-up time between angiograms was 27.8 ± 22.3 (4.0–101.9) months. Progression of RAS occurred in 28 (23%) vessels, regression in 14 (12%) and no significant change in 79 (65%). Multivariate regression analysis showed that baseline proteinuria >0.6 g/day increased the risk of progressive disease (relative risk, RR, 3.8; 95% confidence interval, CI, 1.2–12.1), treatment with statin reduced the risk of progression (RR 0.28; 95% CI 0.10–0.77). 14 renal arteries from 12 patients showed RAS regression with a greater proportion on statin [statin treatment 10 (83%) versus no statin treatment 2 (17%), p = 0.001]. Change in estimated glomerular filtration rate (eGFR) per year was not different between statin- and no-statin-treated groups. Conclusions: Progression or development of RAS was significantly less likely to occur with statin therapy. ΔeGFR did not correlate with progression of RAS, reflecting the importance of intrarenal injury in the aetiology of renal dysfunction. Our results suggest statin therapy can alter the natural history of ARVD.

Dispelling the myth: the use of renin–angiotensin blockade in atheromatous renovascular disease

BACKGROUND Many physicians retain reservations regarding the routine prescription of renin-angiotensin blockade (RAB) in patients with atheromatous renovascular disease (ARVD). Conversely, these patients are in most need of the cardio- and renal protection offered by RAB. This reservation is mostly because of fear of precipitating acute renal deterioration. We aimed to study whether RAB can be used safely in ARVD patients and whether it altered their outcome. METHODS Prospective observational study of all ARVD patients presenting to our tertiary referral centre from 1999-2009. Data capture included usage and tolerability of RAB, and correlation with endpoints of cardiovascular events, dialysis or death. RESULTS Six hundred and twenty-one subjects were available for analysis. Mean age (SD) of the cohort was 71.3 (8.8) years, median (interquartile range) follow-up 3.1 (2.1, 4.8), range 0.2-10.61 years. Seventy-four patients had an intolerance to RAB at study entry. When utilized prospectively, RAB was tolerated in 357 of 378 patients (92%), and this was even seen in 54/69 (78.3%) patients with bilateral>60% renal artery stenosis (RAS) or occlusion. Patients (4/21) who were intolerant of RAB during follow-up (and 12 retrospectively intolerant), underwent renal revascularization which facilitated safe use of these medications post-procedure. On multivariate time-adjusted analysis, patients receiving RAB were significantly less likely to die (P=0.02). CONCLUSION RAB is well tolerated even in patients with bilateral severe RAS and reduced mortality in a large group of ARVD patients. We recommend all ARVD patients be considered for RAB therapy unless an absolute contra-indication exists. Intolerance of these agents due to renal dysfunction should be considered an emerging indication for renal revascularization to facilitate their re-introduction.

The benefit of renal artery stenting in patients with atheromatous renovascular disease and advanced chronic kidney disease

Background: Around 16% of all patients who present with atheromatous renovascular disease (ARVD) in the United States undergo revascularization. Historically, patients with advanced chronic kidney disease (CKD) have been considered least likely to show improvement in renal functional terms, or survival. We aimed to investigate whether differences in outcomes after revascularization compared to medical management might be observed in ARVD patients if stratified by their CKD classes. Methods: Two prospective cohorts, a UK center with a traditionally conservative approach, and a German center who undertook a proactive revascularization approach, were compared. An improvement in renal function was defined as > 20% renal improvement at one years follow‐up. To improve validity and comparability, revascularized patients in the UK center were also used within analyses, Results: 347 (UK conservative group), 89 (UK revascularized group), and 472 (German center) patients were included in the analysis. When subdivided by CKD stage, patient ages between the two centers were comparable. Improvements in renal function were observed in twice as many patients who underwent revascularization as compared to medical treatment, particularly in the latter CKD stages, 15.2 (German revascularization) vs. 0% in CKD 1–2, 12.2 (UK), and 32.8 (German) revascularization vs. 14.1% in CKD3, and 53.1 and 53.8 vs. 28.3 in patients with CKD 4–5. The improvements in eGFR were 10.2 (16) and 8.1 (12.5) ml/min/year in the German and UK revascularized groups, respectively, vs. −0.05 (6.8) ml/min/year in the medical cohort in CKD 4–5. Improvements in blood pressure control were noted at 1 year overall and within each CKD category. Multivariate analysis revealed that revascularization independently reduced the risk of death by 45% in all patients combined (RR 0.55, P = 0.013). Conclusions: Although this study has significant methodological limitations, it does shows that percutaneous renal revascularization can improve renal function in advanced CKD (stages 4–5), and that this can provide a survival advantage in prospective analysis.

The management of renovascular disease: ASTRAL and beyond

Purpose of reviewThis review concentrates on the new findings published in the atheromatous renovascular disease (ARVD) literature since the beginning of 2009, a period in which the results of two randomized control trials have been released. Recent findingsThe key advances have arisen with respect to the epidemiology of ARVD, the effects of revascularization as demonstrated by the results of randomized controlled trials, an understanding of the pathophysiology of the ischaemic kidney, and also there have been further insights regarding the selection of patients for revascularization utilizing structural and functional imaging. SummaryOptimal medical management (and not revascularization therapy) is the established cornerstone for all patients with ARVD. Future studies should be directed to identifying individuals who will significantly benefit from renal revascularization.