Stenting and medical therapy for atherosclerotic renal-artery stenosis

Abstract

Background: Atherosclerotic renal-artery stenosis is a common problem in the elderly. Despite two randomized trials that did not show a benefit of renal-artery stenting with respect to kidney function, the usefulness of stenting for the prevention of major adverse renal and cardiovascular events is uncertain.

Methods: We randomly assigned 947 participants who had atherosclerotic renal-artery stenosis and either systolic hypertension while taking two or more antihypertensive drugs or chronic kidney disease to medical therapy plus renal-artery stenting or medical therapy alone. Participants were followed for the occurrence of adverse cardiovascular and renal events (a composite end point of death from cardiovascular or renal causes, myocardial infarction, stroke, hospitalization for congestive heart failure, progressive renal insufficiency, or the need for renal-replacement therapy).

Results: Over a median follow-up period of 43 months (interquartile range, 31 to 55), the rate of the primary composite end point did not differ significantly between participants who underwent stenting in addition to receiving medical therapy and those who received medical therapy alone (35.1% and 35.8%, respectively; hazard ratio with stenting, 0.94; 95% confidence interval [CI], 0.76 to 1.17; P=0.58). There were also no significant differences between the treatment groups in the rates of the individual components of the primary end point or in all-cause mortality. During follow-up, there was a consistent modest difference in systolic blood pressure favoring the stent group (-2.3 mm Hg; 95% CI, -4.4 to -0.2; P=0.03).

Conclusions: Renal-artery stenting did not confer a significant benefit with respect to the prevention of clinical events when added to comprehensive, multifactorial medical therapy in people with atherosclerotic renal-artery stenosis and hypertension or chronic kidney disease. (Funded by the National Heart, Lung and Blood Institute and others; ClinicalTrials.gov number, NCT00081731.).

Figure 1. Screening, Randomization, and Follow-up

All the participants who underwent randomization were included in the primary analysis, with the exception of the 16 participants (8 in each group) enrolled at a single site at which concerns regarding scientific integrity related to informed consent and eligibility of enrolled participants were raised during monitoring. The 19 patients who crossed over from medical therapy alone to stent plus medical therapy were included in the intention-to-treat analysis in the medical therapy–alone group.

Figure 2. Kaplan–Meier Curves for the Primary Outcome

Survival curves are truncated at 5 years owing to instability of the curves because few participants remained in the study after 5 years.

Figure 3. Forest Plot of Treatment Effects within Subgroups

Hazard ratios for stenting plus medical therapy versus medical therapy alone include all available follow-up data for the primary composite end point. None of the tests for treatment and subgroup interaction were significant (P>0.05). To convert the values for creati-nine to micromoles per liter, multiply by 88.4. The estimated glomerular filtration rate (GFR) was calculated with the use of the modified Modification of Diet in Renal Disease formula. Global ischemia was defined as stenosis of 60% or more of the diameter of all arteries supplying both kidneys or stenosis of 60% or more of the diameter of all arteries supplying a single functioning kidney. For the subgroup of blacks versus others, the analysis was limited to U.S. sites. SBP denotes systolic blood pressure.