Percutaneous renal artery angioplasty: Indications, surgical technique, and long-term outcomes

Abstract

Aim: The purpose of the study was 1) to investigate the incidence of significant renal artery stenosis in patients undergoing coronary angiography, 2) to assess the significance of renal artery stenosis by angiography and intravascular ultrasound (IVUS), 3) to evaluate the plaque composition by virtual histology (VH) and 4) to analyze predictors of renal angioplasty success or failure. Methods: Patients with significant renal artery stenosis by angiography (stenosis diameter ≥ 70%) underwent intravascular ultrasound assessment and plaque characterization by virtual histology. Renal blood flow was assessed by renal frame count and renal blush grade. Renal angioplasty and stenting (PTRA) was performed using the coronary technique with direct stenting. All patients were on follow-up by a nephrologist for one year. Results: The incidence of significant renal artery stenosis was 0.9% in the population of cardiology patients. Thirty five consecutive patients at high cardiovascular risk (18 males, 17 females, age 68 ± 7.9 years) and 41 renal artery stenoses underwent renal artery stenting. The stenosis diameter was 61.2 ± 9.3% by quantitative angiography (QCA) and 63.9 ± 7.8% by IVUS and the area of stenosis was 78.5 ± 9.8% by QCA and 79.3 ± 9.1% by IVUS (r = 0.43, p < 0.01). The plaque composition by VH was fibrous (57.7 ± 11.3%), fibro-fatty (27.8 ± 15.3%), deep calcium (4.5 ± 5.8%) and diffuse necrotic (10.1 ± 7.6%) but without presence of thin intimal cap fibroatheroma. The technical success rate of PTRA was 100% without any major adverse cardiovascular events or reinterventions during hospitalization. At follow-up (12.9 ± 4.6 months), there was a significant decrease in systolic blood pressure (BP) from 166.4 ± 21.0 mmHg to 148.5 ± 23.8 mmHg (p = 0.01) and diastolic BP from 83.5 ± 11.4 mmHg to 78.6 ± 7.6 mmHg (p = 0,05). Creatinine decreased from 132.7 ± 52.11 μmol/l to 130.6 ± 74.3 μmol/l (p = 0.05). Clinical success of PTRA was achieved in 28 out of 35 patients (80%), while in 7 patients (20%) there was no response. Neither baseline demographic factors nor current symptoms, renal flow, stenosis severity or creatinine were predictors of PTRA success or failure. Conclusions: The incidence of significant renal artery stenosis is 1% in cardiology patients. The plaque is composed of fibrous tissue with a deep calcium and low vulnerability index. Renal artery stenosis assessment by angiography correlates with IVUS measurements. PTRA is a feasible and safe procedure with a technical success rate close to 100% and clinical success rate in 80% patients. There are no predictors of PTRA success or failure.