Predictive value of renal resistive index in percutaneous renal interventions for atherosclerotic renal artery stenosis

Background: The clinical benefit of percutaneous interventional therapies for atherosclerotic renal artery stenosis (ARAS) is still obscure. Randomized trials conducted on general patient populations provided unsatisfactory results in justifying the interventional treatment. In this study, the predictive value of renal resistive index (RRI) was retrospectively analyzed in identifying the patients who may benefit from renal angioplasty and stenting. Methods: The records of patients who underwent percutaneous intervention for ARAS were analyzed between 2006 and 2010; we compared the clinical outcomes with preprocedural RRI values. Seventy-three patients were included in the analysis. RRI is calculated as follows: RRI ≤ 1-(Vmin/Vmax). Patients with RRI ≤0.75 were grouped as low RRI (group I) and compared with high RRI patients (RRI >0.75, group II).The comparison was in follow-up systolic and diastolic blood pressures, blood creatinine levels, estimated glomerular filtration rate (eGFR) and need for anti-hypertensive therapy. Data were collected by a customized online database created using Research Electronic Data Capture (REDCap) application. Results: The mean follow-up was 12.4 (9-14) months and 11.1 (5-14) months for groups I and II, respectively (P≤NS). After follow-up, group I patients significantly improved compared to baseline in their blood creatinine levels (2.0 ± 1.2 mg/dL vs 1.5 ± 0.60 mg/dL; P<.05), eGFR (45.2 ± 26.2 mL/min vs 51.6 ± 23.8 mL/min; P<.05), systolic blood pressure (143.6 ± 31.0 mm Hg vs 129.6 ± 18.4 mm Hg; P<.05), diastolic blood pressure (73.6 ± 13.4 mm Hg vs 69.5 ± 9.5 mm Hg; P<.05), and need for anti-hypertensive drugs (2.2 ± 0.9 vs 2.0 ± 0.9; P<.05). However, in group II, follow-up blood creatinine levels (1.8 ± 0.7 mg/dL vs 2.1 ± 1.0 mg/dL; P<.05) increased and eGFR (39.99 ± 22.53 mL/min vs 36.3 ± 23.2 mL/min; P<.05) decreased, indicating continuing clinical deterioration despite the intervention. Conclusion: RRI ≤0.75 may predict better clinical outcomes after renal angioplasty and stenting. Preprocedural RRI can be considered a useful parameter in defining patients who may benefit from interventional procedures.