Predictors of outcome for renal artery stenting performed for salvage of renal function.

OBJECTIVE: To identify preoperative clinical features that predict a durable improvement in renal function with renal artery stenting (RAS). METHODS: Sixty-one patients with renal insufficiency (serum creatinine ≥ 1.5 mg/dL) underwent RAS for renal salvage. Patients were categorized as "responders" if estimated glomerular filtration rate (eGFR) at last follow-up was improved 20% or more over baseline. Patients with stable or worse renal function after RAS were labeled "non-responders." For the purpose of calculating changes in eGFR, patients on dialysis were represented by an eGFR of 10 ml/min/1.73 m(2). Renal volume was estimated as kidney length × width × depth/2. RESULTS: The median age of the cohort was 66 years (interquartile range [IQR], 60-73 years). Median preoperative serum creatinine was 1.8 mg/dL (IQR, 1.6-2.3), and median estimated glomerular filtration rate (eGFR) was 34 mL/min/1.73 m(2) (IQR, 24-45). With stenting, 17 of 61 patients (27.9%) derived a durable improvement in renal function at a median follow-up of 24 months (IQR, 16-33 months). The largest proportion of stented patients (44.3%) had no improvement in renal function after stenting, while a subset (27.9%) experienced a decline in renal function. Responders enjoyed a 47% improvement in renal function from baseline, while non-responders had a 13% decrement in renal function (P < .0001). Responders had a higher baseline serum creatinine, lower eGFR, and a steeper decline in renal function prior to RAS, compared with non-responders. Kidney length, width, depth, and volume were not significantly different between responders and non-responders. Logistic regression analysis identified the rate of decline of renal function prior to stenting as the only independent preoperative predictor of improved renal function after RAS (odds ratio, 3.4; 95% confidence interval, 1.6 to 7.5; P = .0019). The rate of decline in eGFR per week was more than 20-fold greater for responders than non-responders (2.1% vs 0% decline in eGFR per week; P < .0001). No predictors of renal function deterioration after stenting were identified. CONCLUSIONS: The current study found that a steep decline in preoperative renal function portends a higher likelihood of renal salvage from RAS among patients with renal insufficiency. Incorporating this finding into patient selection may improve outcomes for RAS.

Clinical and kidney morphologic predictors of outcome for renal artery stenting: data to inform patient selection.

BACKGROUND: The purpose of the current study was to identify clinical and kidney morphologic features that predict a favorable blood pressure (BP) response to renal artery stenting (RAS). METHODS: The study cohort consisted of 149 patients who underwent primary RAS over 9 years. Patients were categorized as "responders" based on modified American Heart Association guidelines: BP <160/90 mm Hg on fewer antihypertensive medications or diastolic BP <90 mm Hg on the same medications. All other patients were deemed "nonresponders." Renal volume was estimated as kidney length × width × depth/2 based on preoperative computed tomography or magnetic resonance scans. Median follow-up was 19 months (interquartile range [IQR] 10.0-29.5 months). RESULTS: The median age of the cohort was 68 years (IQR, 60-74 years). A favorable BP response was observed in 50 of 149 patients (34%). Multivariate analysis identified three independent predictors of a positive BP response: (1) requirement for four or more medications (odds ratio, 29.9; P = .0001), (2) preoperative diastolic BP >90 mm Hg (OR, 31.4; P = .0011), and (3) preoperative clonidine use (OR, 7.3; P = .029). The BP response rate varied significantly based on the number of predictors present per patient (P < .0001). Among patients with three-drug hypertension, a larger ipsilateral kidney (volume ≥150 cm(3)) increased the BP response rate more than threefold compared with patients with smaller kidneys (63% vs 18% BP response rate; P = .018). CONCLUSIONS: The current study demonstrated that three clinical predictors (≥4 antihypertensive medications, diastolic BP ≥90 mm Hg, and clonidine use) are preoperative predictors of BP response to RAS. Kidney volume may help in discriminating responders from nonresponders among those patients with three-drug hypertension. These parameters may assist clinicians in patient selection and provide more concrete data with which to counsel patients on the likely outcomes for RAS.