Prophylactic selective arterial embolization for renal angiomyolipomas: efficacy and evaluation of predictive factors of significant shrinkage

To evaluate the efficacy of prophylactic selective arterial embolization (SAE) of angiomyolipomas (AMLs) and to find out predictive factors of significant shrinkage of AMLs after SAE.

Patients receiving prophylactic SAE for renal AMLs with complete medical records were included. The changes of the size, urine erythrocyte counts, and serum creatinine of all patients pre- and post-embolization were assessed. Demographic data, symptoms, the background of tuberous sclerosis complex (TSC), aneurysms, enhancement features, initial tumor sizes, and serum creatinine pre-embolization were estimated as predictive factors of significant shrinkage in size.

Forty-five patients receiving prophylactic SAE for AMLs successfully in our center were included with median follow-up of 14.0 months (interquartile range 6.5–40.5). Mean size of AMLs decreased from 10.7 ± 6.2 to 8.3 ± 5.9 cm by 23.4% ± 20.6% at the latest follow-up (P < 0.001). Urine erythrocytes decreased significantly after SAE (11.1 [interquartile range 5.7–23.2] vs. 6.4 [interquartile range 2.7–13.4], P < 0.001). In addition, there was no significant change between the serum creatinine before and after embolization (81.8 ± 14.9 mmol/L vs. 83.6 ± 17.1 mmol/L, P = 0.224). Of the variables mentioned above, only the enhanced area of AMLs before SAE was statistically significant between the groups with and without significant shrinkage (P < 0.001). In multiv-ariate analysis, enhanced area < 25% (AOR = 0.015, 95% CI 0.001–0.367) and having the background of TSC (AOR = 0.056, 95% CI 0.004–0.799) were identified as predictive factors of significant shrinkage of the tumors.

Prophylactic SAE is effective in reducing the size of renal AMLs and decreasing urine erythrocytes with preservation of renal function. Significant shrinkage of AMLs after SAE is modulated by the enhanced area and the background of TSC.