Selective arterial embolization of symptomatic and asymptomatic renal angiomyolipomas: a retrospective study of safety, outcomes and tumor size reduction

Abstract

Background: Angiomyolipoma (AML) is the most common renal benign tumor. Treatment should be considered for symptomatic patients or for those at risk for complications, especially retroperitoneal bleeding which is correlated to tumor size, grade of the angiogenic component and to the presence of tuberous sclerosis complex (TSC). This study reports our single-center experience with the use of selective arterial embolization (SAE) in the management of symptomatic and asymptomatic renal AMLs. Methods:In this retrospective mono-centric study, all demographic and imaging data, medical records, angiographic features, outpatient charts and follow-up visits of patients who underwent prophylactic or emergency SAE for AMLs between January 2005 and July 2016 were reviewed. Tumor size and treatment outcomes were assessed at baseline and after the procedure during follow-up. Computed tomography (CT), magnetic resonance imaging (MRI) or ultrasonography was used to evaluate AML shrinkage. Renal function was measured pre-and post-procedure.Results: Twenty-three patients (18 females, 5 males; median age, 45 years; range, 19-85 years) who underwent SAE either to treat bleeding AML (n=6) or as a prophylactic treatment (n=17) were included.Overall, 34 AMLs were embolized. TSC status was confirmed for 6 patients. Immediate technical success rate was 96% and 4 patients benefitted from an additional procedure. Major complications occurred in 3 patients and minor post-embolization syndrome (PES) in 14 patients. The mean AML size reduction rate was 26.2% after a mean follow-up was 20.5 months (range, 0.5-56 months), and only non-TSC status was significantly associated with better shrinkage of tumor (P=0.022). Intralesional aneurysms were significantly more frequent in patients with hemorrhagic presentation (P=0.008). There was no change in mean creatinine level after SAE.Conclusions: SAE is a safe and effective technique to manage renal AMLs as a preventive treatment as well as in emergency setting, with significant reduction in tumor size during follow-up. A multidisciplinary approach remains fundamental, especially for TSC patients. In addition to size, the presence of intralesional aneurysms should be considered in any prophylactic treatment decision.

Selective Arterial Embolization of Giant Renal Angiomyolipoma Associated with Tuberous Sclerosis Complex Using Particular and Liquid Embolic Agents

“…In experienced hands, glue provides a very fast and effective distal embolization with a high dilution of lipiodol (glue:lipiodol ratio, 1:3-1:6). Glue is a very effective embolic agent for the management of acute hemorrhages, aneurysms, arteriovenous malformations, and fistulas [5,12]. In the present case, initially non-calibrated 355-to 500-mm PVA particles were used to occlude the distal vascular bed.…”

“…Particular embolization was commonly performed with a combination of 350-to 500-mm PVA particles to occlude the distal vascular bed followed by coils to block the arterial inflow and prevent the retrograde filling of the aneurysm and abnormal tumor vessels reference [7]. Coils should be avoided because they only provide proximal vessel occlusion, which may form collaterals around or at the distal level of occlusion, further making embolization difficult or impossible [3][4][5][6].…”

“…Because glue is a permanent embolic agent, its use in embolization needs a high level of experience. Accidental embolization or reflux of glue into non-targeted arteries may result in catastrophic complications [5].…”

“…The freedom from surgery at 5-year follow-up was 94% for SAE [3]. Bardin et al [5] have recently reported 23 symptomatic patients with AML treated by SAE using various embolization agents including particles, coils, and liquid agents; six of these patients were treated because of acute retroperitoneal hemorrhage and the remaining 17 patients were treated prophylactically. Major complications occurred in three patients (renal abscess in two and femoral psodoaneurysms in one) and minor complications in 14 patients as a post-embolization syndrome.…”

“…Because AMLs are usually asymptomatic, tumors of >4-cm diameter are usually symptomatic and present with retroperitoneal and/or urinary bleeding, which can be life threatening [1,3,4]. The standard treatment option in symptomatic patients with AML is nephron-sparing surgery [1,2,5]. However, in the past two decades, selective arterial embolization (SAE) has been used as the first-line treatment option in patients presenting with acute bleeding as well as prophylactically to prevent future bleeding complications [3,6].…”