Renal parenchymal preservation after percutaneous renal angioplasty and stenting

Background

The intent of endovascular therapy for symptomatic atherosclerotic renal artery stenosis (ARAS) is to preserve parenchyma and avoid renal-related morbidity. The aim of this study is to examine the impact of renal artery intervention on parenchymal preservation.

Methods

We performed a retrospective analysis of records from patients who underwent endovascular intervention for ARAS and were followed by duplex ultrasound between 1990 and 2008. Renal volume (in cm³) was estimated in all patients as renal length (cm) × renal width (cm) × renal depth (cm) × 0.5. The normal renal volume was calculated as 2 × body weight (kg) in cm³. Failure of preservation was considered to be a persistent 10% decrease in volume. Clinical benefit defined as freedom from renal-related morbidity (increase in persistent creatinine >20% of baseline, progression to hemodialysis, death from renal-related causes) was calculated.

Results

Five hundred ninety-two renal artery interventions were performed. One hundred eighty-six kidneys suffered parenchymal loss (>5%) with an actuarial parenchymal loss rate of 29% ± 1% at five years respectively. There were no significant differences in age, gender, starting renal volume, or kidney size. However, patients with parenchymal loss had lower eGFR (45 ± 24 vs 53 ± 24 mL/min/1.73 m²; Loss vs noLoss, P = .0002, Mean ± SD) higher resistive index (0.75 ± 0.9 vs 0.73 ± 0.10; P = .0001) and worse nephrosclerosis grade (1.43 ± 0.55 vs 1.30 ± 0.49; P = .006) then those not suffering parenchymal loss. Parenchymal loss was associated with significantly worse five-year survival (26% ± 4% vs 48% ± 2%; Loss vs noLoss; P < .001) and freedom from renal-related morbidity (70% ± 5% vs 82% ± 2%; P < .05) with increased numbers progressing to dialysis (17% vs 7%; P < .006).

Conclusion

While parenchymal preservation occurs in most patients, parenchymal loss occurs in 31% of patients and is associated with markers of impaired parenchymal perfusion (resistive index and nephrosclerosis grade) at the time of intervention. Pre-existing renal size or volumes were not predictive of parenchymal loss. Parenchymal loss is associated with a significant decrease in survival and a marked increased renal related morbidity and progression to hemodialysis.