The intent of endovascular therapy for symptomatic atherosclerotic renal artery stenosis (ARAS) is to preserve parenchyma and avoid renal-related morbidity.
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) x renal width (cm) x renal depth (cm)x0.5. The normal renal volume was calculated as 2 x body weight (kg) in cm3. Failure of preservation was considered to be a persistent 5% 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
592 renal artery interventions were performed. 188 kidneys suffered parenchymal loss (>5%) with an actuarial parenchymal loss rate of 29±1% at 5 years respectively. There were no significant differences in age, gender, starting renal volume or kidney size (Table 1). However, patients with parenchymal loss had lower eGFR, higher resistive index and worse glomerulosclerosis grade then those not suffering parenchymal loss (Table 1). Parenchymal loss was associated with significantly worse survival and freedom from renal-related morbidity with increased numbers progressing to dialysis.
Parenchymal loss occurs in 31% of patients and is associated with markers of impaired parenchymal perfusion (RI and GSG) 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. Monitoring parenchymal loss will identify high-risk patients after renal intervention.
Methodist Debakey Heart and Vascular Center, Houston, TX
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