Renal function, complications, and outcomes of a reduction in tumor size after transarterial embolization for renal angiomyolipomas: a meta-analysis

Clinical practice recommendations for kidney involvement in tuberous sclerosis complex: a consensus statement by the ERKNet Working Group for Autosomal Dominant Structural Kidney Disorders and the ERA Genes & Kidney Working Group

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the presence of proliferative lesions throughout the body. Management of TSC is challenging because patients have a multifaceted systemic illness with prominent neurological and developmental impact as well as potentially severe kidney, heart and lung phenotypes; however, every organ system can be involved. Adequate care for patients with TSC requires a coordinated effort involving a multidisciplinary team of clinicians and support staff. This clinical practice recommendation was developed by nephrologists, urologists, paediatric radiologists, interventional radiologists, geneticists, pathologists, and patient and family group representatives, with a focus on TSC-associated kidney manifestations. Careful monitoring of kidney function and assessment of kidney structural lesions by imaging enable early interventions that can preserve kidney function through targeted approaches. Here, we summarize the current evidence and present recommendations for the multidisciplinary management of kidney involvement in TSC.

The radiomics-clinical nomogram for predicting the response to initial superselective arterial embolization in renal angiomyolipoma, a preliminary study

Purpose

The aim of this study was to explore a radiomics-clinical model for predicting the response to initial superselective arterial embolization (SAE) in renal angiomyolipoma (RAML).

Materials and methods

A total of 78 patients with RAML were retrospectively enrolled. Clinical data were recorded and evaluated. Radiomic features were extracted from preoperative contrast-enhanced CT (CECT). Least absolute shrinkage and selection operator (LASSO) and intra- and inter-class correlation coefficients (ICCs) were used in feature selection. Logistic regression analysis was performed to develop the radiomics, clinical, and combined models where the fivefold cross-validation method was used. The predictive performance and calibration were evaluated by the receiver operating characteristic (ROC) curve and calibration curve. Decision curve analysis (DCA) was used to measure clinical usefulness.

Results

The tumor shrinkage rate was 29.7% in total, and both fat and angiomyogenic components were significantly reduced. In the radiomics model, 12 significant features were selected. In the clinical model, maximum diameter (p = 0.001), angiomyogenic tissue ratio (p = 0.032), aneurysms (p = 0.048), and post-SAE time (p = 0.002) were significantly associated with greater volume reduction after SAE. Because of the severe linear dependence between radiomics signature and some clinical parameters, the combined model eventually included Rad-score, aneurysm, and post-SAE time. The radiomics-clinical model showed better discrimination (mean AUC = 0.83) than the radiomics model (mean AUC = 0.60) and the clinical model (mean AUC = 0.82). Calibration curve and DCA showed the goodness of fit and clinical usefulness of the radiomics-clinical model.

Conclusions

The radiomics-clinical model incorporating radiomics features and clinical parameters can potentially predict the positive response to initial SAE in RAML and provide support for clinical treatment decisions.

Serum lactate dehydrogenase concentration after transcatheter renal artery embolization correlates with reduction in renal angiomyolipoma volume

BACKGROUND

The extent of renal angiomyolipoma (AML) volume reduction after renal transcatheter arterial embolization (TAE) varies between patients, with no predictive measure available.

PURPOSE

To determine whether the serum lactate dehydrogenase (LDH) concentration shortly after TAE correlates with the extent of tumor shrinkage.

MATERIAL AND METHODS

In a cohort of 36 patients undergoing prophylactic renal TAE for unruptured renal AML, we retrospectively acquired data from patient medical records, including serum LDH before and within 7 days after TAE and the tumor volume before and 12-36 months after TAE. The relationship between the serum level of LDH and reduction in tumor volume was evaluated using Spearman correlation analysis.

RESULTS

The median LDH concentration was significantly higher after TAE than before (909.0 U/L vs. 186.5 U/L). This early post-TAE serum LDH level and LDH index (post-TAE LDH / pre-TAE LDH) correlated significantly and positively with the absolute decrease in tumor volume (both P < 0.0001). We observed no significant correlation between the relative tumor volume reduction and serum LDH level or LDH index.

CONCLUSION

Serum LDH elevation occurs shortly after TAE and correlates with the extent of absolute decrease in AML volume at 12-36 months after TAE. Further large-scale studies are warranted to confirm the predictive role of post-TAE serum LDH level and LDH index in tumor shrinkage in patients with unruptured renal AML.

Safety, Efficacy and Mid-Term Outcome for Transarterial Embolization (TAE) of Renal Angiomyolipoma (AML) Using Ethylene Vinyl Alcohol Copolymer Liquid Embolic Agent (EVOH)

Transarterial embolization (TAE) of renal angiomyolipoma (AML) is effective in treating and preventing hemorrhage. We report our experience using EVOH with a single-center retrospective study of all AML embolized with EVOH between June 2013 and March 2022 at the Montpellier University Hospital. A total of 29 embolizations were carried out in 24 consecutive patients (mean age: 53.86 years; 21 women and 3 men) with 25 AMLs for severe bleeding, symptomatic AML, tumor size > 4 cm, or presence of aneurysm(s) > 5 mm. Data collected included imaging and clinical outcomes, tuberous sclerosis complex status, change in AML volume, rebleeding, renal function, volume and concentration of EVOH used, and complications. Out of 29 embolizations performed for 25 AMLs, four were performed in an emergency. Technical success was achieved for 24/25 AMLs. Mean AML volume reduction was 53.59% after a mean follow-up time of 446 days using MRI or CT scan. Aneurysms on angiogram and the symptomatological nature of AML, as well as secondary TAE and multiple arterial pedicles, were statistically associated (p < 0.05). Two patients (8%) underwent nephrectomy after TAE. Four patients had a second embolization. Minor and major complication rates were 12% and 8%, respectively. Neither rebleeding nor renal function impairment was noticed. TAE of AML using EVOH is, thus, highly effective and safe.

Renal Functional Outcomes in Patients With Angiomyolipomas: Surveillance vs Embolization vs Nephrectomy

OBJECTIVE

To investigate renal functional outcomes of surveillance, embolization, and surgery for angiomyolipomas (AML).

METHODS

Longitudinal data regarding patients with AML were analyzed retrospectively in this 2-center study. Demographic, radiographic, and functional data were tabulated according to treatment type. Primary outcome was change in renal function from diagnosis to within 6 months postdiagnosis (interim) and to latest glomerular filtration rate (GFR) assessment.

RESULTS

318 patients were diagnosed with AMLs; mean follow-up was 6.2 years. 184 patients (57.9%) were managed with surveillance, 30 (9.4%) underwent embolization, and 103 (32.4%) underwent surgery (91 partial nephrectomy; 12 radical nephrectomy). Baseline characteristics, including tumor size, age, and race differed between the 3 groups (P<.05). Surveilled AMLs were smaller (P<.001) than the intervention groups: 1.9 cm vs 5.4 cm (embolization) and 4.9 cm (surgery). Greater interim decreases in GFR were observed following intervention with embolization (-14.0%) or surgery (-11.8%), when compared with surveillance (-4.1%); however, this was not statistically significant (P=.19). Latest GFR was also reduced more (P=.02) with embolization (-14.1%) and surgery (-14.7%) when compared to surveillance (-6.0%). At latest determination, chronic kidney disease progression by at least one stage occurred in 37.8% overall, including 33.7% of surveilled patients, and was not statistically different across the three cohorts (P=.074).

CONCLUSION

Within the study limitations, surveillance appears to be appropriate for most AML patients; embolization and surgical intervention should be reserved for selected patients with large and/or symptomatic AML. Renal functional deterioration is common in patients with AML, whether managed with surveillance, embolization, or surgery. Long-term monitoring of renal function should be obligatory for all AML patients.

Safety, Efficacy, and Predictors for Late Reintervention After Embolization of Renal Angiomyolipomas – Embolization renal angiomyolipoma

Purpose To retrospectively analyze the procedural and long-term clinical outcome of the selective embolization of renal angiomyolipoma. In addition, potential predictive factors for higher risk of late re-intervention were analyzed.

Methods Retrospective monocentric study, including 34 consecutive patients, analyzing the safety, efficiency, and long-term clinical outcome of catheter-directed embolization of renal AML. Additionally, the difference in postembolization renal function between patients embolized in the acute and in the elective setting was analyzed. Secondly, we also evaluated whether volume/diameter of the AML and presence of intralesional aneurysms are risk factors for late re-intervention.

Results Embolization of renal AML was performed to control volume (n = 21; 62 %) or to stop spontaneous hemorrhage (n = 13; 38 %) with angiographic success in all cases but was associated with renal abscess (n = 1) and pulmonary embolism (n = 1) without a significant difference in renal function before and after embolization (P = 0.513). Volume/diameter (P = 0.276/P = 0.21) and presence of aneurysms before embolization (P = 0.37) are not predictive for a higher risk of late re-intervention.

Conclusion Catheter-directed embolization is a safe and effective treatment modality for asymptomatic and bleeding renal AML, without a negative impact on renal function. Initial mass volume/diameter or presence/absence of intralesional aneurysms does not seem to be predictive for late re-intervention.

Key Points:

Citation Format

Transarterial Embolization for Sporadic Renal Angiomyolipoma: Patient Selection and Technical Considerations for Optimal Therapeutic Outcomes

Although renal angiomyolipoma (AML) is a benign tumor, treatment may be necessary occasionally because it can cause potentially life-threatening retroperitoneal hemorrhage. Transarterial embolization (TAE) is a safe and effective treatment option to prevent the hemorrhagic rupture of AMLs and relieve the symptoms caused by enlarged lesions or active bleeding. However, there is no clear consensus regarding the indications for prophylactic TAE in patients with sporadic renal AMLs. In urgent TAE for bleeding AMLs, there is a likelihood of incomplete embolization when the focus is on stabilizing the clinical symptoms. This pictorial essay discusses the patient selection and technical considerations to achieve optimal therapeutic effects as well as the follow-up findings after TAE.

A Report of 61 Cases of Retroperitoneal Laparoscopic Nephron-Sparing Surgery and Factors Affecting Postoperative Renal Function

Objective

To explore the situation of 61 patients with renal tumors who underwent retroperitoneal laparoscopic nephron-sparing surgery (RLNSS) and the factors affecting postoperative renal function.

Methods

A total of 61 patients with renal tumors who underwent RLNSS in our hospital from January 2018 to January 2021 were included in this study. All patients were treated with RLNSS. The clinical data of patients were recorded. Before operation and 3 months after operation, the change value of glomerular filtration rate (ΔGFR) was measured by the Gates method. Multivariate linear regression was used to analyze the related factors affecting postoperative renal function.

Results

All 61 patients successfully completed the operation. The mean operative time was 60–150 min‚ average (98.75 ± 14.38) min. The estimated intraoperative blood loss was 20–310 ml‚ average (107.93 ± 68.55) ml. Intraoperative warm ischemia time (WIT) was 0–39 min, with an average of (21.16 ± 6.47) min. All patients' pathological margins were negative after operation. In all patients, there were 5 postoperative complications, including 2 cases of renal wound bleeding (3.28%), 1 case of hematuria (1.64%), 1 case of urinary fistula (1.64%), and 1 case of subcutaneous emphysema (1.64%). There were significant differences in tumor diameter, preoperative GFR, operation time and WIT (P < 0.05). Multivariate analysis showed that tumor diameter, preoperative GFR, and WIT were all factors affecting the postoperative renal function of patients with RLNSS (P < 0.05).

Conclusion

RLNSS has a good curative effect on patients with renal tumor, and tumor diameter, preoperative GFR, and WIT were all factors affecting the postoperative renal function of patients with RLNSS.

Selective Arterial Embolization of Renal Angiomyolipomas with a N-Butyl Cyanoacrylate-Lipiodol Mixture: Efficacy, Safety, Short- and Mid-Term Outcomes

Selective arterial embolization (SAE) for renal angiomyolipoma (rAML) is effective to treat or prevent bleeding. We report our experience using a cyanoacrylate–Lipiodol mixture. We performed a single-center retrospective review of all rAMLs embolized with cyanoacrylate glue between July 2014 and June 2020. Demographics, tuberous sclerosis complex (TSC) status, clinical presentation, angiography features, and follow-up data were recorded. Pre- and post-procedure rAML sizes and volumes were estimated from computed tomography (CT) or magnetic resonance imaging (MRI) studies. Kidney function was assessed before and after the procedure. We identified 24 patients (22 females and 2 males, mean age 51 years) treated for 27 AMLs, either prophylactically (n = 20) or as an emergency (n = 4). Technical success was achieved for 25/27 AMLs; two patients, each with a single AML, required nephrectomy and repeated embolization, respectively. Major complications occurred in three patients and minor complications such as postembolization syndrome in 15 patients. AML volume reduction after embolization was 55.1% after a mean follow-up of 15 months (range, 1–72 months). Factors associated with greater volume reduction were a smaller percentage of fat (p = 0.001), larger initial rAML volume (p = 0.014), and longer follow-up (p = 0.0001). The mean creatinine level did not change after SAE. Embolization of rAMLs with a mixture of cyanoacrylate and Lipiodol is feasible, safe, and effective in significantly decreasing tumor volume.

Urgent Transcatheter Arterial Embolization for Wunderlich Syndrome With Hypovolemic Shock Secondary to Ruptured Renal Angiomyolipoma

Purpose: Wunderlich syndrome (WS) with hypovolemic shock secondary to ruptured renal angiomyolipoma (rAML) represents an urgent condition. Hence, we reported our experience with transcatheter arterial embolization (TAE) using different embolic materials under this condition.

Methods: This retrospective study consisted of 22 patients. Embolic materials including particles, microcoils, and liquid embolic agents were selectively used based on the decisions of interventional radiologists. Technical success was defined as the complete occlusion of bleeding vessels on the final renal angiogram. Clinical success was defined as the absence of re-hemorrhage needed for repeat endovascular or surgery treatment after TAE.

Results: The articulated materials were used when WS presented without aneurysms; a combination of particulate materials and microcoils or Glubran 2 alone were used for WS with aneurysms. The technical success based on 24 episodes of TAEs in 22 patients was 100% (24 of 24). Repeat TAE was achieved in two patients with hemorrhages re-occurring two days after the initial embolization with microcoils alone. The clinical success was 90.9% (20 of 22). No nontarget embolization or embolization-related complications occurred during the TAE procedure. Of the patients, 27.3% (6 of 22) experienced minor complications of post-embolization syndrome (PES). During a median follow-up time of 34 months, no recurrent hemorrhage that required repeat endovascular or surgical treatment for hemostasis occurred.

Conclusion: Urgent TAE with the selective use of different embolic materials is an effective alternative to control WS with hypovolemic shock secondary to ruptured rAML. The condition of presenting with or without aneurysms may determine the embolic materials employed.

[Tuberous sclerosis system: A review]

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects different organs and caused by loss-of-function mutations in one of two genes: TSC1 or TSC2. TSC1 or TSC2 gene mutation lead to dysfunction of hamartin or tuberin, respectively. Hamartin and tuberin form a protein complex that helps regulate cellular proliferation. These proteins form a complex that constitutively inhibits the mammalian target of rapamycin (mTOR) signaling pathway, leading to permanent activation of mTOR signaling within all TSC-associated lesions. Major features of TSC include tumors of the brain, skin, heart, lungs and kidneys, seizures and TSC-associated neuropsychiatric disorders, which can include autism spectrum disorder and cognitive disability. These disorders are usually diagnosed in children and adults. Specific guidelines for diagnosis, surveillance, and management have been proposed by the International Tuberous Sclerosis Complex Consensus Group. Several randomized controlled trials led to regulatory approval of the use of mTOR inhibitors for the treatment of renal angiomyolipomas, brain subependymal giant cell astrocytomas, refractory epilepsy and pulmonary lymphangioleiomyomatosis.

Angiomyolipoma rupture: does size always matter?

Angiomyolipoma (AML) is the most common benign renal neoplasm. Although asymptomatic lesions rarely lead to clinical dilemma, the management of ruptured tumours can become challenging. The size of the tumour has been widely accepted as a prognostic factor for intervention but there exists some evidence against considering the size as the only prognostic factor for intervention in AML. In our study, we described three recent cases of ruptured AML which were treated with different approaches – in two cases radical nephrectomy was performed, and in one patient a minimally invasive approach was adopted.

A new management strategy for renal angiomyolipomas: superselective arterial embolization in combination with radiofrequency ablation

Background

The present study analyzed the safety and efficacy of superselective arterial embolization (SAE) combined with radiofrequency ablation (RFA) to treat renal angiomyolipoma (RAML).

Methods

This retrospective study included the clinical data of 6 patients with RAML treated between March 2016 and October 2017. All patients underwent RFA treatment immediately after SAE guided by angio-computed tomography (angio-CT). The tumor size, renal function and complications, and time to recurrence were compared before and after treatment.

Results

The success rate of the SAE + RFA technique was 100%, and no serious complications were found during or after surgery. After treatment, the patients' symptoms, including low back pain and hematuria, were relieved. The pre-treatment creatinine level (55.6±11.0 µmol/L) did not differ significantly from the post-treatment creatinine level (68.2±13.7 µmol/L), which was measured 1 day after surgery (t=1.75, P=0.109). The mean follow-up time was 29.5±6.1 months. By the end of the follow-up period, the maximum diameter of the tumor was 3.1±0.6 cm, which was significantly smaller than the pre-treatment diameter of 5.9±1.01 cm (t=5.83, P<0.001). At 3 months after surgery, the maximum diameter of the tumor was reduced by 22-38% in all 6 patients. At the last follow-up examination, the maximum diameter of the tumor was reduced by 36-61%. Contrast-enhanced CT or magnetic resonance imaging scans showed that the enhanced part of the original lesion had disappeared, the renal parenchyma was full of even fat signals, and only one patient had new enhanced lesions at the site of the original lesions.

Conclusions

SAE combined with RFA is a safe and effective treatment for RAML, and its strengths qualify it to become a new treatment strategy for RAML.