Impact of Renal Stenting on Blood Pressure Studied

April 28, 2011—The Society for Vascular Surgery (SVS) announced that J. Gregory Modrall, MD, published a retrospective study examining clinical and kidney morphologic features that predict a favorable blood pressure (BP) response to renal artery stenting (RAS) in the Journal of Vascular Surgery (2011;53:1282–1290).

According to SVS, the investigators at the University of Texas Southwestern Medical Center and its affiliated hospitals performed RAS in 149 patients (185 arteries, 36 bilateral) between January 1, 2000 and July 1, 2008. The median age of the cohort was 68 years, and median follow-up was 19 months. Patients were categorized as “responders” based on modified American Heart Association guidelines: BP < 160/90 mm Hg if on fewer antihypertensive medications than before stenting or a reduction of an average diastolic BP < 90 mm Hg on the same medications. All other patients were deemed “nonresponders.”


During a multivariate analysis, the investigators found that three preoperative clinical variables (four or more blood pressure medications, diastolic BP ≥ 90 mm Hg, and clonidine use) may be useful predictors of BP response to RAS, whereas patients with none of these predictors present before RAS are highly unlikely to respond to stenting with improved BP (response rate of 1.5%).



 As detailed by SVS, a favorable BP response to RAS was observed in 50 of 149 patients. After RAS, the 50 responders had a median decrease in systolic BP of 33 mm Hg and a median decrease in diastolic BP of 15 mm Hg. The BP response rate varied significantly based on the number of predictors present per patient. With one predictor, the BP response rate rose to 45%; those with two or more predictors had at least a 76% probability of response. 



Renal volume was estimated as kidney length X width X depth/2 based on preoperative computed tomography or magnetic resonance scans. During the study, 86 of the 149 patients had preoperative contrast enhanced computer tomography or magnetic resonance scans to measure parameters of kidney morphology.



“Kidney volume may help in discriminating responders from nonresponders among patient subsets who are marginal candidates for stenting,” commented Dr. Modrall. He noted that among those patients with three-drug hypertension, a larger ipsilateral kidney (volume ≥ 150 cm³) increased the BP response rate more than threefold compared with patients with smaller kidneys (63% vs 18% BP response rate).


Dr. Modrall advised that being cognizant of these predictors of BP response may assist clinicians in patient selection and provide more concrete data with which to counsel patients on the likely outcomes for RAS.