Renal artery stent placement for restoration of renal function in hemodialysis recipients with renal artery stenosis

Atherosclerotic renovascular disease: a clinical practice document by the European Renal Best Practice (ERBP) board of the European Renal Association (ERA) and the Working Group Hypertension and the Kidney of the European Society of Hypertension (ESH)

Atherosclerotic renovascular disease (ARVD) is the most common type of renal artery stenosis. It represents a common health problem with clinical presentations relevant to many medical specialties and carries a high risk for future cardiovascular and renal events, as well as overall mortality. The available evidence regarding the management of ARVD is conflicting. Randomized controlled trials failed to demonstrate superiority of percutaneous transluminal renal artery angioplasty (PTRA) with or without stenting in addition to standard medical therapy compared with medical therapy alone in lowering blood pressure levels or preventing adverse renal and cardiovascular outcomes in patients with ARVD, but they carried several limitations and met important criticism. Observational studies showed that PTRA is associated with future cardiorenal benefits in patients presenting with high-risk ARVD phenotypes (i.e. flash pulmonary oedema, resistant hypertension or rapid loss of kidney function). This clinical practice document, prepared by experts from the European Renal Best Practice (ERBP) board of the European Renal Association (ERA) and from the Working Group on Hypertension and the Kidney of the European Society of Hypertension (ESH), summarizes current knowledge in epidemiology, pathophysiology and diagnostic assessment of ARVD and presents, following a systematic literature review, key evidence relevant to treatment, with an aim to support clinicians in decision making and everyday management of patients with this condition.

How should we define appropriate patients for percutaneous transluminal renal angioplasty treatment?

Renovascular hypertension (RVH) is one of the most common causes of secondary hypertension and can result in resistant hypertension. RVH is associated with an increased risk for progressive decline in renal function, cardiac destabilization syndromes including "flash" pulmonary edema, recurrent congestive heart failure, and cerebrocardiovascular disease. The most common cause of renal artery stenosis (RAS) is atherosclerotic lesions, followed by fibromuscular dysplasia. The endovascular technique of percutaneous transluminal renal angioplasty (PTRA) with or without stenting is one of the standard treatments for RAS. Randomized controlled trials comparing medical therapy with PTRA to medical therapy alone have failed to show a benefit of PTRA; however, the subjects of these randomized clinical trials were limited to atherosclerotic RAS patients, and patients with the most severe RAS, who would be more likely to benefit from PTRA, might not have been enrolled in these trials. This review compares international guidelines related to PTRA, reevaluates the effects of PTRA treatment on blood pressure and renal and cardiac function, discusses strategies for the management of RVH patients, and identifies factors that may predict which patients are most likely to benefit from PTRA.

Impact of Renal Function Trajectory on Renal Replacement Therapy and Mortality Risk after Renal Artery Revascularization

PURPOSE

To determine the impact of renal function trajectory, defined as the change in renal function over time before and after renal artery stent placement, on long-term risk for renal replacement therapy (RRT) and mortality.

MATERIALS AND METHODS

Estimated glomerular filtration rates (eGFRs) 6-12 months before renal artery stent placement, at the time of intervention, and 6-12 months after intervention were determined in 398 patients. The effect of eGFR change before and after renal artery stent placement was calculated. Cox proportional-hazards ratio was used to determine the risks for RRT and all-cause mortality.

RESULTS

The risk for RRT was significantly influenced by eGFR change from the time of intervention to follow-up at 6-12 month after treatment (P = .02). In addition, among patients with a postintervention eGFR ≤ 40 mL/min/1.73 m², for every 1 unit of eGFR increase, there was a significant decrease in RRT and all-cause mortality (P < .001 and P < .001, respectively). Secondary parameters that increased RRT risk included diabetes at the time of intervention (P = .03), increased baseline proteinuria (P < .001), and stage 4 or 5 chronic kidney disease (CKD; P = .01 and P = .003, respectively). Multivariate analysis demonstrated higher all-cause mortality rates among patients with diabetes at the time of intervention (P = .009).

CONCLUSIONS

Postintervention eGFR trajectory improvement approaching 40 mL/min/1.73 m² was associated with decreased RRT and mortality risk. These findings suggest that patients with advanced CKD and renal artery stenosis may benefit from revascularization regardless of their preinterventional renal function measurement.

Renal Artery Stenosis: When to Revascularize in 2017

Atherosclerotic renal artery stenosis is the leading cause of secondary hypertension; it can also cause progressive renal insufficiency and cardiovascular complications such as refractory heart failure and flash pulmonary edema. Medical therapy including risk factor modification, renin-angiotensin-aldosterone system antagonists, lipid lowering agents, and antiplatelet therapy is the first line of treatment in all patients. Patients with uncontrolled renovascular hypertension despite optimal medical therapy, ischemic nephropathy, and cardiac destabilization syndromes who have severe renal artery stenosis are likely to benefit from renal artery revascularization. Screening for renal artery stenosis can be done with Doppler ultrasonography, computed tomographic angiography and magnetic resonance angiography. Invasive physiologic measurements are useful to confirm the severity of renal hypoperfusion and therefore improve the selection patients likely to respond to renal artery revascularization. Primary patency exceeds 80% at 5 years and surveillance for in-stent restenosis can be done with periodic clinical, laboratory, and imaging follow-up.

Approach to atherosclerotic renovascular disease: 2016

The management of atherosclerotic renal artery stenosis in patients with hypertension or impaired renal function remains a clinical dilemma. The current general consensus, supported by the results of the Angioplasty and Stenting for Renal Atherosclerotic Lesions and Cardiovascular Outcomes for Renal Artery Lesions trials, argues strongly against endovascular intervention in favor of optimal medical management. We discuss the limitations and implications of the contemporary clinical trials and present our approach and formulate clear recommendations to help with the management of patients with atherosclerotic narrowing of the renal artery.

Mortality and Renal Replacement Therapy after Renal Artery Stent Placement for Atherosclerotic Renovascular Disease

PURPOSE

To identify risk factors for progression to renal replacement therapy (RRT) and all-cause mortality in patients who underwent renal artery (RA) stent placement for atherosclerotic renal artery stenosis (RAS).

MATERIALS AND METHODS

A retrospective study from June 1996 to June 2009 identified 1,052 patients who underwent RA stent placement. Glomerular filtration rate at time of RA stent placement was estimated from serum creatinine level and divided into chronic kidney disease (CKD) stages 1-5. Univariate and multivariable Cox proportional hazards models were used to determine which factors were associated with each endpoint.

RESULTS

Times to progression to all-cause mortality and RRT were similar for CKD stages 1/2/3A and served as the reference group. In multivariable analysis, high-grade proteinuria (P < .001) and higher CKD stage (5 vs 1/2/3A [P < .001], 4 vs 1/2/3A [P < .001], 3B vs 1/2/3A [P = .02]) remained independently associated with increased risk of progression to RRT. Angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) use was associated with decreased risk of progression to RRT (P = .03). Higher CKD stage (5 vs 1/2/3A [P < .001], 4 vs 1/2/3A [P = .004]), carotid artery disease (P < .001), diabetes mellitus (P = .002), and high-grade proteinuria (P < .001) remained independently associated with all-cause mortality. Statin use was associated with decreased risk of all-cause mortality (P < .001).

CONCLUSIONS

Patients with atherosclerotic RAS who undergo RA stent placement and have high-grade proteinuria and CKD stage 3B/4/5 have increased risk of progression to RRT. Patients with high-grade proteinuria, CKD stage 3B/4/5, carotid artery disease, or diabetes have increased risk for all-cause mortality after renal artery stent placement. Patients receiving ACEI/ARBs have a decreased risk of progression to RRT, and patients receiving statins have a decreased risk of all-cause mortality.

Percutaneous revascularization for ischemic nephropathy: the past, present, and future

Occlusion of the renal arteries can threaten the viability of the kidney when severe, in addition to accelerating hypertension and circulatory congestion. Renal artery stenting procedures have evolved from a treatment mainly for renovascular hypertension to a maneuver capable of recovering threatened renal function in patients with “ischemic nephropathy” and improving management of congestive heart failure. Improved catheter design and techniques have reduced, but not eliminated hazards associated with renovascular stenting. Expanded use of endovascular stent grafts to treat abdominal aortic aneurysms has introduced a new indication for renal artery stenting to protect the renal circulation when grafts cross the origins of the renal arteries. Although controversial, prospective randomized trials to evaluate the added benefit of revascularization to current medical therapy for atherosclerotic renal artery stenosis until now have failed to identify major benefits regarding either renal function or blood pressure control. These studies have been limited by selection bias and have been harshly criticized. While studies of tissue oxygenation using blood oxygen level dependent (BOLD) MR establish that kidneys can adapt to reduced blood flow to some degree, more severe occlusive disease leads to cortical hypoxia associated with microvascular rarefication, inflammatory injury and fibrosis. Current research is directed toward identifying pathways of irreversible kidney injury due to vascular occlusion and to increase the potential for renal repair after restoring renal artery patency. The role of nephrologists likely will focus upon recognizing the limits of renal adaptation to vascular disease and identifying kidneys truly at risk for ischemic injury at a time point when renal revascularization can still be of benefit to recovering kidney function.

Endovascular intervention for renal artery stenosis

Renovascular diseases are common conditions with important implications on cardiovascular morbidity and mortality. Renal artery stenosis (RAS) is present in 1-5% of patients with hypertension (HTN) in the US with the vast majority of caused by atherosclerosis. Atherosclerotic RAS is related not only to uncontrolled HTN, but also to renal dysfunction. Atherosclerotic RAS in the USA has been reported to account for approximately 14-16% of new patients requiring dialysis each year. Hence a concerted effort was made in the last decade to treat renovascular stenosis using newly developed endovascular therapies to improve cardiovascular morbidity and renal function. A review on new advances in the endovascular management of renal artery stenosis with low profile stents, embolic protection devices, and drug eluting stents is presented.