Arterial Embolization for the Treatment of Renal Masses and Traumatic Renal Injuries

Renal embolization for trauma: a narrative review

Renal injuries commonly occur in association with blunt trauma, especially in the setting of motor vehicle accidents. Contrast-enhanced computed tomography is considered the gold-standard imaging modality to assess patients for renal injuries in the setting of blunt and penetrating trauma, and to help classify injuries based on the American Association for the Surgery of Trauma injury scoring scale. The management of renal trauma has evolved in the past several decades, with a notable shift towards a more conservative, nonoperative approach. Advancements in imaging and interventional radiological techniques have enabled diagnostic angiography with angiographic catheter-directed embolization to become a viable option, making it possible to avoid surgical interventions that pose an increased risk of nephrectomy. This review describes the current management of renal trauma, with an emphasis on renal artery embolization techniques.

Embolisation Using Microvascular Plugs for Peripheral Applications: Technical Results and Mid-Term Outcomes

The Micro Vascular Plug® (MVP, Medtronic) is a mechanical embolic agent available in small sizes that allows for distal embolisation. The objective of this retrospective observational single-centre study was to assess MVP embolisation procedures performed at a university hospital. The 33 patients who underwent MVP embolisation in 2021 were included (mean age, 64; 24 males and 9 females). The primary endpoint was technical success, which was defined as a full first-attempt occlusion with one or more MVPs, as documented on the end-of-procedure angiogram. In all patients, 51 MVPs were used overall, with other embolic agents in 23 of the 33 cases (usually coils and/or glue); 22 of the 33 procedures were emergent for bleeding and 11 were planned for other indications. Of the three technical failures, two were due to an angled target artery configuration precluding microcatheterisation and one to failure of the device to release from its wire. The technical success rate was thus 90.9%. No patient experienced MVP migration or other major complications. Five patients had recurrent clinical symptoms; in four cases, the cause was collateral development, and in one case, the cause was incomplete initial embolisation. No instances of recanalisation were documented during the short follow-up of 12 months, for a 100% secondary clinical success rate. At our tertiary-level centre, the MVP was both effective and safe for peripheral applications. Interventional radiologists should be conversant with the techniques and indications of MVP embolisation.

Efficacy and safety analysis of TACE + sunitinib vs. sunitinib in the treatment of unresectable advanced renal cell carcinoma: a retrospective study

BACKGROUND

Since renal cell carcinoma(RCC) is insensitive to conventional chemoradiotherapy, molecularly targeted drugs are commonly used treatments for unresectable advanced RCC. The aim of this study was to explore the efficacy and safety of TACE + sunitinib vs. sunitinib in the treatment of unresectable advanced RCC.

METHODS

This study included 98 patients with unresectable advanced RCC who were treated in Union Hospital from January 2015 to December 2018, and they met the criteria. They were divided into two groups: TACE + Sunitinib group (N = 47) and Sunitinib group (N = 51). We conducted a retrospective study to analyze the efficacy and safety of the two groups of patients.

RESULTS

(1)TACE + Sunitinib group: 4 patients (8.5%) achieved CR, 27 patients (57.5%) achieved PR, 9 patients (19.1%) achieved SD, and 7 patients (14.9%) achieved PD. Sunitinib group, 0 patients (0%) achieved CR, 20 patients (39.2%) achieved PR, 14 patients (27.5%) achieved SD, and 17 patients (33.3%) achieved PD. (P = 0.017) (2)ORR: TACE + sunitinib group, 66.0%; sunitinib group, 39.2%. (P = 0.009) (3)DCR: TACE + sunitinib group, 85.1%; sunitinib group, 66.7%. (P = 0.038) (4) In the TACE + sunitinib group, mPFS was 15.6 months, mOS was 35.0 months; in the sunitinib group, the mPFS was 10.9 months, mOS was 25.7 months. (P < 0.001) (5) The incidence of abdominal pain, fever, and vomiting was higher in the TACE + sunitinib group than in the sunitinib group (abdominal pain: 55.3% vs. 13.7%; fever: 61.7% vs. 7.8%; vomiting: 40.4% vs. 19.6%; P < 0.05). The technical success rate of TACE in TACE + Sunitinib group is 100%.

CONCLUSIONS

The TACE + sunitinib group had higher ORR and DCR, longer OS and PFS than the sunitinib alone group. TACE combined with sunitinib can play a complementary role and is a safe and effective treatment for advanced RCC.

The Role of Renal Artery Embolisation in the Management of Blunt Renal Injuries: A Review

Renal injuries are the most common urinary tract injury secondary to external abdominal trauma. They are caused by blunt, penetrating and iatrogenic mechanisms. Despite the high number of blunt renal injuries, little evidence is available to guide management, especially with the evolution of embolisation as a minimally invasive treatment. Consequently, clinical practice is driven by results of observational studies and anecdote. We have reviewed the current trends in practice when using renal artery embolisation in the management of blunt renal injuries. Three key principles are highlighted. First, high-grade blunt renal injuries can be successfully managed with embolisation. Second, embolisation should be considered when there is radiological evidence of active contrast extravasation, pseudoaneurysm or arteriovenous fistula. Third, embolisation can be used to manage blunt renal injuries in haemodynamically unstable patients. Beyond this, evidence regarding optimal technique, CT indications, clinical status, comorbidities and complications are inconclusive. We discuss the implications for clinical practice and how these findings should define the agenda for future clinical research.

Renal Arteries Revisited: Anatomy, Pathologic Entities, and Implications for Endovascular Management

The renal arteries (RAs) are important vessels that usually arise from the abdominal aorta and supply the kidneys; thus, these arteries play a vital role in physiologic functions such as hemofiltration and blood pressure regulation. An understanding of the basis for embryologic development and the frequently variable anatomy of the RAs is necessary to fully appreciate the range of diseases and the implications for procedural planning. Hemorrhage from an RA is relatively common and is typically traumatic or spontaneous, with the latter form often seen in association with underlying tumors or arteriopathy. Accurate diagnostic evaluation of RA disease due to conditions such as atherosclerosis, fibromuscular dysplasia, vasculitis, aneurysm, arteriovenous shunt, embolic disease, and dissection is dependent on the use of multimodality imaging and is essential for selecting appropriate clinical management, with endovascular therapy having a key role in treatment. Surgical considerations include extra-anatomic renal bypass, which remains an important treatment option even in this era of endovascular therapy, and RA embolization as an adjunct to tumor surgery. A novel area of research interest is the potential role of RA denervation in the management of refractory hypertension. ^©RSNA, 2021.

Interventional Radiology in Renal Trauma

Traumatic injuries to the kidney and collecting system can range widely from small lacerations to significant bleeding and its sequelae. Urinary obstruction can occur in the renal pelvis, ureters, or urethra. Interventional radiology plays a significant role in treatment and management, in many cases requiring emergent action. Endovascular embolization is frequently the first-line approach to treating hemorrhage. Percutaneous interventions for urinary obstruction include nephrostomy and suprapubic catheter placement. In this article, we outline the clinical approach and interventional methods used in the evaluation and treatment of renal trauma. Several case presentations demonstrate the role of interventional radiology in renal trauma.

Endovascular Interventional Radiology of the Urogenital Tract

Interventional radiology of the male urogenital system includes percutaneous and endovascular procedures, and these last consist mostly of transcatheter arterial embolizations. At the kidney level, arterial embolizations are performed mainly for palliative treatment of parenchymal tumors, for renal traumas and, less frequently, for arteriovenous fistulas and renal aneurysms and pseudoaneurysms. These latter may often require emergency intervention as they can cause renal or peri-renal hematomas or significant hematuria. Transcatheter arterial embolization is also an effective therapy for intractable severe bladder hematuria secondary to a number of neoplastic and inflammatory conditions in the pelvis, including unresectable bladder cancer and radiation-induced or cyclophosphamide-induced hemorrhagic cystitis. Endovascular interventional procedures for the penis are indicated for the treatment of post-traumatic priapism. In this article, we review the main endovascular radiological interventions of the male urogenital system, describing the technical aspects, results, and complications of each procedure at the various anatomical districts.

Interventional radiology in the management of renal vascular injury: A prospective study

Introduction

Endovascular and percutaneous interventions are promising alternatives to surgical management of traumatic renal injuries and often avert the need for nephrectomies. In this study, we aimed to evaluate the role of interventional radiology and angiographic interventions in the management of renal vascular injury.

Materials and Methods

Our prospective study was performed over a period of 6 months. Twenty-five patients who presented with either persistent hematuria or hemodynamic instability after traumatic or iatrogenic renal injuries were selected. Angiographic embolization using varying combinations of coils, glue, and Gelfoam^® was performed to address the vascular injuries, either directly in hemodynamically unstable patients or after preprocedural imaging in hemodynamically stable patients. Patients were then followed up till discharge from hospital 48 h later and at 2 weeks and 4 weeks postprocedure for any recurrence of hematuria or hemodynamic instability. Technical and clinical success rates were calculated using descriptive statistics.

Results

Pseudoaneurysms were the most common form of arterial injury (22 cases), followed by arteriovenous fistula (8) and active extravasation (5). Segmental arteries are the most commonly involved (12 cases), followed by interlobar (9) and arcuate (3) arteries. Gelfoam^® was used in five patients with active contrast extravasation and was 100% effective in arresting active bleeding. Coiling alone had a 79.16% technical success rate in management, while additional use of glue in four failed cases led to a 95.83% technical success rate in the first attempt. The ultimate technical and clinical success rate of interventional radiology in renal trauma management (after the second attempt in one failed case) was 100%.

Conclusion

Endovascular management is an effective and safe alternative to surgical management of both iatrogenic and accidental renal vascular injuries.

Amplatzer vascular plug in renal artery embolization: case report and review of the literature

Background

Arterial embolization constitutes a safe and effective therapeutic possibility in the treatment of numerous renal pathologies in election and in urgency. Over the years, numerous embolizing materials have been proposed: fibrin (temporary occlusion), glues, coils, and microspheres. The use of St. Jude Amplatzer vascular plug (AVP) constitutes a more recent and less widespread therapeutic choice, and its use in the renal district is not yet widespread although potentially very valid.

Case presentation

We present 3 renal arterial embolizations performed with AVP performed between January 2019 and February 2020: two patients had a very bulky renal heteroplastic lesion and were candidates for nephrectomy, and a third patient instead was affected by a high-flow FAV post-biopsy. In our experience, the use of AVP for the treatment of renal arteriovenous fistula and neoplastic masses has given excellent results without any complications during and after the treatment. In all cases, a single plug was used which perfectly adapted to the target artery resulting in complete occlusion of the vessel in a short time.

Conclusion

Renal artery embolization performed with AVP has growing potential and numerous advantages in terms of the time of the procedure, speed of embolization, and precision of occlusion, but with a relative increase in costs.

Update on Transradial Access for Percutaneous Transcatheter Visceral Artery Embolization

Transfemoral access (TFA) is a widely used first-line approach for most peripheral vascular interventions. Since its introduction in cardiologic and neurointerventional procedures, several advantages of transradial access (TRA) over TFA have been demonstrated, such as patient preference, lower complication rates, early ambulation, and shorter hospital stay. However, studies reporting the safety and efficacy of this approach for peripheral vascular interventions performed by interventional radiologists are relatively few. This review aimed to summarize the technique and clinical applications of TRA in percutaneous transcatheter visceral artery embolization and the management of complications.

Percutaneous image-guided ablation: From techniques to treatments

Image-guided ablation is performed by percutaneously introducing ablation probes to deliver energy into a tumor to destroy it in a controlled and localized fashion. Ablation modalities can be broadly classified as thermal or non-thermal based on the mechanism of tumor destruction and are performed using different types of image guidance for planning, delivering and follow-up of the treatment. Ablation is performed in a minimally invasive fashion, providing greater residual organ preservation with minimal morbidity to the patient. Image-guided ablation is being used in the clinic for the treatment of primary and metastatic tumors, and this article reviews state of the art for the treatment of malignancies in the liver, lung, kidney and musculoskeletal tissue.

Our experience in emergency treatment of renal haemorrhage

INTRODUCTION

Renal haemorrhage is a potentially life-threatening event requiring emergency surgery. Endovascular therapy is currently the first-line treatment option.

OBJECTIVES

Review patients with renal haemorrhage who required emergency endovascular therapy at our center. Evaluate the causes of the bleeding, the treatment performed and the clinical outcomes.

MATERIAL AND METHODS

We performed a retrospective analysis of consecutive patients with renal bleeding who underwent endovascular therapy from June 2012 to June 2017 at Hospital Universitari Joan XXIII (Tarragona, Spain). Demographic data (age, gender and comorbidity) and other related variables were collected (mechanism of injury, haemodynamic stability and anticoagulant therapy). We also studied the CT angiography findings, time from diagnosis to surgery, endovascular technique and materials used, extent of tissue embolised and outcomes.

RESULTS

Twenty-two (22) patients were included with a mean age of 63 (range 19-85). The aetiology of injuries included: renal biopsy (n=7, 31.8%), bleeding from malignant kidney tumour (n=5, 22.7%), trauma (n=4, 18.2%), angiomyolipoma (n=2, 9.1%), spontaneous bleeding (n=2, 9.1%) and surgical complications (n=2, 9.1%). The endovascular therapy technique was embolisation in all cases. The following materials were used: spheres (9.1%); coils (63.6%); spheres + coils (18.2%); and spheres + plug (9.1%). In 17 cases (77.3%), selective embolisation was performed and in five cases (22.7%), embolisation of the whole kidney. Clinical and technical success rates of 100% were recorded. The 30-day mortality rate was 9.1%.

CONCLUSION

We believe that endovascular therapy is an effective modality for the management of renal bleeding which, in many cases, enables a large part of the renal tissue to be preserved.

Can we predict the existence of extrarenal feeders to renal angiomyolipomas?

OBJECTIVES

To identify factors predicting the presence of extrarenal feeders to renal angiomyolipomas (AMLs) METHODS: This is a retrospective study of 44 patients with 58 renal AMLs embolized in our department. Arteriography obtained during embolization and CT angiography obtained before and after embolization were reviewed to characterize AMLs with and without extrarenal feeders. Tumor characteristics were compared between the two groups. Simple logistic regression and ROC curve analysis were performed. P < 0.05 was considered to be statistically significant.

RESULTS

Of the 58 AMLs reviewed, 29% had extrarenal arteries and 71% did not. AMLs with extrarenal feeders were significantly larger than those without, in terms of volume (median, 368 mL versus 109 mL, p < 0.0002) and the largest diameter (mean, 12.0 cm versus 7.7 cm, p < 0.0001). Patient age, presence of tuberous sclerosis complex or sporadic lymphangioleiomyomatosis, and tumor location did not differ between the groups. The largest diameter and volume had similar predictive values for the presence of extrarenal feeders (AUC, 0.83 versus 0.82, p = 0.673). Extrarenal feeders were present in 0%, 21%, and 79% of the AMLs ≤ 6.5 cm, AMLs 6.6-10.5 cm, and AMLs > 10.5 cm, respectively.

CONCLUSIONS

AML size correlates with the presence of extrarenal feeders, with the largest diameter and volume being significant predictors. AMLs > 10.5 cm had a high chance of extrarenal feeders, making it mandatory to search for feeders to them in order to avoid incomplete embolization; AMLs ≤ 6.5 cm did not have extrarenal feeders, making a search for them unnecessary in these cases.

KEY POINTS

• The presence of extrarenal feeders to renal angiomyolipoma is associated with tumor size, but not with patient age, concomitant disease, or tumor location. • The largest diameter and volume predict the presence of extrarenal feeders to AML, with similar predictive values. • AMLs > 10.5 cm have a high chance (79%) of extrarenal feeders, making it mandatory to search for feeders to them in order to avoid incomplete embolization; AMLs ≤ 6.5 cm do not have extrarenal feeders, making a search for them unnecessary in these cases.

Renal Arteries Embolization in Unresectable Clear Cell Renal Carcinoma: First Time Experience at Haji Adam Malik Hospital

OBJECTIVE

To report a case of renal arterial embolisation (RAE) in unresectable renal tumour before nephrectomy.

CASE REPORT

On presentation, the clinical features of this patient, including medical history, signs and symptoms, imaging examinations were recorded. After diagnosis and initial treatment, the result and histopathological examination were performed and discussed. We performed RAE in the unresectable renal tumour in the 28-year-old male that was complaining a palpable pain right flank mass and intermittent hematuria that had been observed five months earlier. A month after RAE, the tumour shrinks and become resectable. The parameter used was tumour volume, propulsion and component, with subjective value VAS, hematuria symptom and Quality Of Life Score EORTC-QLQ C30. The next step we performed nephrectomy with histopathology results in Clear Cell Renal Carcinoma (CCRC).

CONCLUSION

RAE is an effective therapeutic and adjuvant tool because it facilitates the dissection of unresectable large renal tumours and tumours with extensive involvement around the renal hilum; it leading to lower overall morbidity. However, the lack of randomised prospective studies is the primary reason that RAE is not used often before surgery.

Effect of renal embolization in patients with synchronous metastatic renal cell carcinoma: a retrospective comparison of cytoreductive nephrectomy and systemic medical therapy

Objective

To compare survival outcomes for renal embolization (RE) to cytoreductive nephrectomy (CN) and no primary renal treatment (NT) among patients with synchronous metastatic renal cell carcinoma (mRCC) treated using either targeted therapy (TT) or immunotherapy (IT).

Results

The median follow-up duration was 81.3 months, with a duration of first-line treatment of 3.5 months. Among the 211 patients, the median PFS and OS were 4.4 and 10.6 months. Specifically for patients receiving TT (124 patients), the PFS and OS were 5.5 and 12.0 months. An intervention effect was identified only for OS, with a median OS of 20.1, 8.8 and 9.3 months for CN, RE and NT, respectively. After stratification by risk classification, CN provided a significant benefit on OS, compared to RE and NT, for patients with an intermediate risk (MSKCC). For those with a poor risk (Heng criteria), NT provided better survival than PFS (p=0.003), and a comparable survival to RE (p > 0.05).

Materials and Methods

Retrospective analysis of 211 patients, 87 treated with IT and 124 with TT, retrieved from our RCC database. Patients' risk factors for survival was evaluated using the Heng and MSKCC criteria, with only patients with an intermediate or poor survival risk included in the analysis. Between-group comparisons were evaluated with respect to progression-free survival (PFS) and overall survival (OS).

Conclusions

The differential effect of CN and RE on OS appears to be modulated by risk classification. In patients with a poor risk, RE should be implemented after careful consideration of comorbidities and life expectancy.

Endovascular management of arterial injuries after blunt or iatrogenic renal trauma

The kidney is the third most common abdominal organ to be injured in trauma, following the spleen and liver, respectively. The most commonly used classification scheme is the American Association for the Surgery of Trauma (AAST) classification of blunt renal injuries, which grades renal injury according to the size of laceration and its proximity to the renal hilum. Arteriovenous fistula and pseudoaneurysm are the most common iatrogenic biopsy-related or surgery-related vascular injuries in native kidneys. The approach to renal artery injuries has changed over time from more aggressive intervention to more conservative observational or endovascular management, including selective transcatheter arterial embolization (TAE) and the placement of stents/stent grafts. In this article, we describe the role and technical aspects of endovascular interventions in the management of arterial injuries after blunt or iatrogenic renal trauma.