Recent studies of renal artery stenosis (RAS) failed to demonstrate greater benefit from angioplasty in terms of blood pressure (BP) lowering than medical treatment. Not all RAS are haemodynamically significant and identification of patients likely to benefit from angioplasty remains essential.
We examined whether performing renal venous renin studies under stringent conditions might predict BP improvement. Patients with at least 60% RAS who underwent renal venous renin measurements in 2008–2013 were identified. Renal venous renin lateralization ratios (RVRRs) were calculated by dividing venous renin from the stenotic kidney with contralateral levels before and after stimulation with enalaprilat or captopril. Benefit was defined as BP less than 140/90 mmHg without medication, 10% decreased mean BP without increased daily defined doses (DDDs) or decreased DDD without a significant increase of mean BP.
Twenty-eight patients were treated medically and 42 with angioplasty (median age 60.1 years, 41% male, 29% chronic kidney disease, 50% resistant hypertension). At 11.4 ± 3.3 months, 69% of patients treated with angioplasty had BP benefit compared with 25% with medical treatment (P < 0.001). Logistic regression identified resistant hypertension [odds ratio (OR) 0.18, 95% confidence interval (95% CI) 0.04–0.82, P = 0.03] and baseline DDD (OR 0.69, 95% CI 0.48–0.98, P = 0.04) as being negatively associated, and positive stimulated RVRR (OR 21.6, 95% CI 3.50–133.3, P = 0.001) positively associated with benefit from angioplasty. On multivariate logistic regression, only stimulated RVRR positivity predicted BP benefit (OR 20.5, 95% CI 2.9–145.0, P = 0.003).
: These findings suggest that a positive stimulated RVRR measured under optimal conditions may help to identify patients with RAS likely to improve from angioplasty.
aEndocrine Hypertension Research Centre, University of Queensland School of Medicine, Greenslopes and Princess Alexandra Hospitals, Brisbane, Queensland, Australia
bHôpital du Sacré-Coeur de Montréal, University of Montreal, Montreal, Quebec, Canada
Correspondence to Michael Stowasser, Endocrine Hypertension Research Centre, University of Queensland School of Medicine, Princess Alexandra Hospital, Woolloongabba, Brisbane, QLD 4102, Australia Tel: +61 7 31762694; fax: +61 7 31762969; e-mail: firstname.lastname@example.org
Abbreviations: AUC, area under the curve; BNP, brain natriuretic peptide; BOLD_MRI, blood oxygen level dependent MRI; BP, blood pressure; CI, confidence intervals; CKD, chronic kidney disease; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration equation; CLSR, contralateral suppression ratios; DDD, daily defined doses of antihypertensive medications; eGFR, estimated glomerular filtration rate; OR, odds ratio; RAS, renal artery stenosis; RCT, randomized controlled trials; ROC, receiver-operating characteristics; RVRR, renal venous renin lateralization ratio; RVRs, renal venous renin studies
Received 2 February, 2015
Revised 16 April, 2015
Accepted 16 April, 2015