This article is a collaboration between MedPage Today® and:
Renal artery stenting appears to improve the outlook for patients with renal artery stenosis and hypertension that's difficult to manage, the single-arm HERCULES trial showed.
The procedure resulted in a significant drop in blood pressure accompanied by low rates of in-stent restenosis and other complications, according to Michael Jaff, DO, of Massachusetts General Hospital in Boston, and colleagues.
The average systolic blood pressure at baseline was 162 mm Hg among patients taking an average of 3.4 antihypertensives, and within 1 month of stenting it had declined to 145 mm Hg, an effect sustained through 9 months (P<0.0001), the researchers reported online in Catheterization and Cardiovascular Interventions.
The study, which was initially reported at the Society for Cardiovascular Angiography and Interventions meeting last year, "highlights that when appropriate patients are selected for renal artery stenting, impressive reductions in blood pressure may be anticipated," the authors wrote.
HERCULES was a multicenter, single-arm trial that evaluated use of the RX Herculink Elite Renal Stent System by Abbott Vascular -- which sponsored the study -- in patients with atherosclerotic renal artery stenosis and uncontrolled hypertension. Patients were enrolled between 2007 and 2009.
It included 202 patients with 241 total lesions, including 78 bilateral lesions. The patients had a systolic blood pressure of 140 mm Hg or higher or a diastolic pressure of 90 mm Hg or high despite using maximal doses of at least two antihypertensives; about 70% of patients were taking three or more medications.
The patients also had renal artery stenosis remaining after a suboptimal revascularization result from percutaneous transluminal angioplasty using a standard balloon dilatation catheter.
At baseline, average serum creatinine was 1.2 mg/dL and 61.5% of patients had an estimated glomerular filtration rate less than 60 mL/min/1.73 m2.
The in-stent restenosis rate determined by duplex ultrasound, angiography, or both at 9 months after the procedure -- the primary outcome -- was 10.5%. The upper limit of the confidence interval was 14.7%, indicating a successful outcome because it was lower than the performance goal of 28.6%.
There was a significant drop in blood pressure during follow-up, with the greatest reductions seen in patients with the highest readings at baseline. Medication use and renal function did not change.
The researchers also measured brain natriuretic peptide as a possible predictor for response to stenting. Levels of the biomarkers decreased during the study, but neither baseline level nor the change in levels was related to the observed blood pressure response.
"Further studies for predictors of clinical response following percutaneous renal revascularization are needed," the authors noted.
One patient died and two had renal atheromatous embolization resulting in kidney damage within 30 days. When additionally considering the target lesion revascularization rate at 9 months, the major adverse event-free rate was 94.8%.
The major limitation of HERCULES, according to Jaff and colleagues, was the lack of a control arm. Also, the majority of patients were Caucasian, so the ﬁndings may not be applicable to other ethnic and racial groups.
In an accompanying editorial, William Hillegass, MD, MPH, of the University of Alabama at Birmingham, pointed out that two randomized trials -- ASTRAL and STAR -- failed to show a benefit for renal artery stenting.
He noted, however, that ASTRAL enrolled patients with relatively mild hypertension and modest stenosis. STAR included patients with renal insufficiency and well-controlled blood pressure on medical therapy.
"Rather than testing the efficacy of renal artery stenting in patients expected to benefit, both ASTRAL and STAR should be viewed as trials largely assessing extension of [the] therapy to off-target patient groups of unknown benefit," Hillegass wrote.
"Until a practical and ethical randomized strategy tests renal artery stenting in on-target patients with high a priori likelihood of benefit, observational data such as the HERCULES trial...should not be totally discounted in assessing the efficacy of [the treatment]," he said.
From the American Heart Association:
- SCAI: Renal Artery Stenting Works, but Biomarker Fails
- 2011 ACCF/AHA/SCAI Guidelines for Percutaneous Coronary Intervention
HERCULES was sponsored by Abbott Vascular.
Jaff reported relationships with Abbott Vascular, Cordis Corporation, Covidien/eV3, and VIVA Physicians, a 501 c 3 not-for-profit education and research organization. His co-authors reported relationships with Nexeon MedSystems, CeloNova BioSciences, and Abbott Vascular. Three of the authors are full-time employees of Abbott Vascular and shareholders of Abbott Laboratories.
Hillegass declared no significant conflict of interest. He did report making less than 1% of his income from performing renal artery procedures.
- Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner
Catheterization and Cardiovascular InterventionsSource Reference: Jaff M, et al "Significant reduction in systolic blood pressure following renal artery stenting in patients with uncontrolled hypertension: results from the HERCULES trial" Catheter Cardiovasc Interv 2012.
Catheterization and Cardiovascular InterventionsSource Reference: Hillegass W, et al "Benefit of renal artery stenting: is on-target therapy the observational bias?" Catheter Cardiovasc Interv 2012.