Three Decades of Atherosclerotic Reno-vascular Disease Management - Changing Outcomes in an Observational Study

Design of a clinical risk calculator for major clinical outcomes in patients with atherosclerotic renovascular disease

BACKGROUND

Risk stratification in atherosclerotic renovascular disease (ARVD) can influence treatment decisions and facilitate patient selection for revascularization. In this study, we aim to use variables with the best predictive value to design a risk calculator that can assist clinicians with risk stratification and outcome prediction.

METHODS

Patients with a radiological diagnosis of ARVD referred to our tertiary renal centre were recruited into this prospective cohort study between 1986 and 2014. Primary clinical endpoints included: death, progression to end-stage kidney disease and cardiovascular events (CVE). A stepwise regression model was used to select variables with the most significant hazard ratio for each clinical endpoint. The risk calculator was designed using Hypertext Markup Language. Survival and CVE-free survival were estimated at 1, 5 and 10 years.

RESULTS

In total, 872 patients were recruited into the Salford ARVD study with a median follow-up period of 54.9 months (interquartile range 20.2-96.0). Only models predicting death and CVE showed good performance (C-index >0.80). Survival probabilities obtained from the risk calculator show that most patients with ARVD have reduced long-term survival. Revascularization improved outcomes in patients with higher baseline estimated glomerular filtration rate and lower proteinuria but not in those with co-existing comorbidities and higher levels of baseline proteinuria.

CONCLUSIONS

Although this risk calculator requires further independent validation in other ARVD cohorts, this study shows that a small number of easily obtained variables can help predict clinical outcomes and encourage a patient-specific therapeutic approach.

Association of novel biomarkers with major clinical outcomes in a cohort of patients with atherosclerotic renovascular disease

Introduction

In this study, we investigate whether the addition of biomarkers to a model based on traditional risk factors improves risk prediction and patient selection for revascularization in atherosclerotic renovascular disease.

Methods

Patients in the Salford Renovascular Study who had the following biomarkers analysed on a baseline sample were included in this study: FGF-23, Cystatin C, kidney injury molecule-1, myeloperoxidase, neutrophil gelatinase-associated lipocalin, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), high-sensitivity Troponin T and anti-apolipoprotein A1 IgG. Cox proportional hazards models and net reclassification index were used to study the effects of either individual or a panel of biomarkers on predicting death, end-stage kidney disease and cardiovascular events.

Results

A total of 112 patients were followed up for a median 59.9 months (IQR 33.6–86.9). In total, 75 patients died, 21 reached end-stage kidney disease and 36 suffered a cardiovascular event. Only NT-proBNP maintained a statistically significant association with all end-points (death: HR 1.62 [95% CI 1.26–2.10], P < 0.0005; end-stage kidney disease: HR 1.51 [95% 1.19–1.91], P = 0.001; cardiovascular event: HR 1.56 [95% CI 1.23–1.97], P < 0.0005). Risk reclassification improved with addition of all biomarkers as a panel to the base model. Only patients with NT-proBNP concentrations above 300 ng/L gained benefit from revascularization with regard to all adverse end-points compared with medically managed patients.

Conclusions

NT-proBNP is independently associated with increased risk for all adverse events in atherosclerotic renovascular disease. Novel biomarkers may have an incremental risk predictive value when used in combination with traditional risk factors, and NT-proBNP may have value in patient selection for revascularization. Given the small size of this study, larger multicentre studies are required to validate these findings.

Atherosclerotic Renal Artery Stenosis: Should we Intervene Earlier?

Purpose of Review

Randomized trials have failed to show clinical benefit in patients with atherosclerotic renal artery stenosis who were treated with angioplasty with or without stenting. However, these studies were done in patients with a high-grade stenosis. This paper examines whether there are arguments to consider patients with low-grade stenosis for angioplasty.

Recent Findings

Patients with low-grade (< 50%) atherosclerotic renal artery stenosis have an excess risk for cardiovascular and renal complications. This could be related to inflammatory factors being generated by the stenotic kidney. Moreover, even a kidney with low-grade stenosis clears less or produces more of the natural nitric oxide inhibitor ADMA.

Summary

Patients with low-grade atherosclerotic renal artery stenosis have an increased risk for a variety of complications. In addition, the abnormality is progressive. There is a case for setting up a prospective trial to examine whether angioplasty confers benefit in patients with low-grade renal artery stenosis.

Long-Term Renal and Cardiac Outcomes after Stenting in Patients with Resistant Hypertension and Atherosclerotic Renal Artery Stenosis

BACKGROUND/AIMS

Atherosclerotic renal artery stenosis (ARAS) is frequently detected in patients with resistant hypertension (RHTN), but the evidence supporting the utility of renal revascularization in these patients is limited. This prospective, observational study investigates the outcomes of renal stenting in patients with RHTN and hemodynamically significant ARAS.

METHODS

Fifty-four patients with RHTN were selected because of angiographic evidence of ARAS >70% and were followed for 4 years after renal stenting. Renal function and echocardiographic variables were assessed at baseline and during follow-up.

RESULTS

Blood pressure decreased rapidly after renal stenting and was normalized in 67% of patients at six months, with significant reduction in the number of antihypertensive drugs. Creatinine clearance increased in 39% of patients, decreased in 52%, and remained stable in the remaining 9%, with an average value that had a nonsignificant decrease during follow-up. Urinary albumin excretion did not change throughout the study. After 4 years, left ventricular (LV) wall thickness and concentric geometry decreased significantly and variables of LV diastolic function improved.

CONCLUSION

In patients with RHTN, stenting of hemodynamically significant ARAS decreases blood pressure, preserves renal function in a substantial proportion of patients, and improves LV structure and function, suggesting the opportunity for timely identification of ARAS in these patients.