Renal Artery Stenting Did Not Affect Stenosis Severity, Systolic Blood Pressure Elevation

In patients with a history of hypertension, renal artery stenting (RAS) plus medical therapy failed to improve stenosis severity, systolic blood pressure (BP) elevation, or translesion pressure gradient when compared with medical therapy alone, according to an exploratory analysis of the CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) trial. 

For this analysis, researchers of CORAL, which is the largest randomized trial examining RAS, aimed to determine whether extreme pressure gradients, stenosis severity, and baseline BP impact RAS outcomes in patients with a history of hypertension—a question that is currently being debated.

The primary end point was defined as event-free survival, with the event encompassing a composite endpoint of myocardial infarction, stroke, hospitalization for congestive heart failure, progressive renal insufficiency or end-stage renal disease, and cardiovascular or renal-related death. 

Overall, the intention-to-treat population included 931 patients, of whom 459 were randomized to receive RAS plus medical therapy and 472 to receive medical therapy alone.

Using either quartiles or clinically significant thresholds, the researchers found no consistent treatment effect with RAS compared with medical therapy for each of the variables, including rate of stenosis (both investigator reported and core lab measured), systolic BP, peak systolic pressure gradient, and mean systolic pressure gradient. 

“These variables have previously been felt to be important, but a positive treatment effect of stenting in these subgroups was not observed,” the researchers wrote. “Specifically, the CORAL study data does not support a benefit of stenting based on degree of stenosis, hemodynamic significance of the lesion, or higher pretreatment blood pressure.”

In addition, each component of the primary end point was evaluated for relationships with these variables, but the results were also negative. 

The researchers noted, however, that despite eligibility criteria in CORAL including high-risk patients, it is impossible to exclude selection bias among physicians referring patients for entry into an intervention trial.

“But because the CORAL study’s population was similar in terms of risk to those in uncontrolled studies that reported a benefit of stent placement, that potential criticism is suspect,” they wrote. “There were patients that were intentionally excluded in CORAL, such as those with advanced chronic kidney disease, a population that was under represented in the CORAL study generally and for whom inferences from these data are not appropriate.”

Reference

1. Murphy TP, Cooper CJ, Matsumoto AH, et al. Renal artery stent outcomes: Effect of baseline blood pressure, stenosis severity, and translesion pressure gradient. J Am Coll Cardiol. 2015;66(22):2487-2494; doi:10.1016/j.jacc.2015.09.073.