Transcatheter arterial renal and adrenal embolization with iohexol-ethanol solutions. Animal experimental study and clinical application

Novel radiopaque ethanol injection: physicochemical properties, animal experiments, and clinical application in vascular malformations

BACKGROUND

Despite the efficacy of absolute ethanol (EtOH), its radiolucency introduces several risks in interventional therapy for treating vascular malformations. This study aims to develop a novel radiopaque ethanol injection (REI) to address this issue.

METHODS

Iopromide is mixed with ethanol to achieve radiopacity and improve the physicochemical properties of the solution. Overall, 82 male New Zealand white rabbits are selected for in vivo radiopacity testing, peripheral vein sclerosis [animals were divided into the following 5 groups (n = 6): negative control (NC, saline, 0.250 ml/kg), positive control (EtOH, 0.250 ml/kg), low-dose REI (L-D REI, 0.125 ml/kg), moderate-dose REI (M-D REI, 0.250 ml/kg), and high-dose REI (H-D REI 0.375 ml/kg)], pharmacokinetic analyses (the blood sample was harvested before injection, 5 min, 10 min, 20 min, 40 min, 1 h, 2 h, 4 h, and 8 h after injection in peripheral vein sclerosis experiment), peripheral artery embolization [animals were divided into the following 5 groups (n = 3): NC (saline, 0.250 ml/kg), positive control (EtOH, 0.250 ml/kg), L-D REI (0.125 ml/kg), M-D REI (0.250 ml/kg), and H-D REI (0.375 ml/kg)], kidney transcatheter arterial embolization [animals were divided into the following 4 groups (n = 3): positive control (EtOH, 0.250 ml/kg), L-D REI (0.125 ml/kg), M-D REI (0.250 ml/kg), and H-D REI (0.375 ml/kg); each healthy kidney was injected with saline as negative control], and biosafety evaluations [animals were divided into the following 5 groups (n = 3): NC (0.250 ml/kg), high-dose EtOH (0.375 ml/kg), L-D REI (0.125 ml/kg), M-D REI (0.250 ml/kg), and H-D REI (0.375 ml/kg)]. Then, a prospective cohort study involving 6 patients with peripheral venous malformations (VMs) is performed to explore the clinical safety and effectiveness of REI. From Jun 1, 2023 to August 31, 2023, 6 patients [age: (33.3 ± 17.2) years] with lingual VMs received sclerotherapy of REI and 2-month follow-up. Adverse events and serious adverse events were evaluated, whereas the efficacy of REI was determined by both the traceability of the REI under DSA throughout the entire injection and the therapeutic effect 2 months after a single injection.

RESULTS

The REI contains 81.4% ethanol (v/v) and 111.3 mg/ml iodine, which can be traced throughout the injection in the animals and patients. The REI also exerts a similar effect as EtOH on peripheral venous sclerosis, peripheral arterial embolization, and renal embolization. Furthermore, the REI can be metabolized at a similar rate compared to EtOH and Ultravist® and did not cause injury to the animals' heart, liver, spleen, lungs, kidneys and brain. No REI-related adverse effects have occurred during sclerotherapy of VMs, and 4/6 patients (66.7%) have achieved complete response at follow-up.

CONCLUSION

In conclusion, REI is safe, exerts therapeutic effects, and compensates for the radiolucency of EtOH in treating VMs.

TRIAL REGISTRATION

The clinical trial was registered as No. ChiCTR2300071751 on May 24 2023.

Imaging-guided percutaneous radiofrequency ablation of adrenal metastases: preliminary results at a single institution with a single device

The aim of this study was to show the feasibility, safety, imaging appearance, and short-term efficacy of image-guided percutaneous radiofrequency ablation (RFA) of adrenal metastases (AM). Seven imaging-guided percutaneous RFA treatments were performed in six patients (two men and four women; mean age, 67.2 years; range, 55-74 years) with six AM who were referred to our institution from 2003 to 2006. One patient was treated twice for recurrence after first treatment. The average diameter of the treated AM was 29 mm (range, 15-40 mm). In all patients, the diagnosis was obtained with CT current protocols in use at our institution and confirmed by pathology with an image-guided biopsy. No major complications occurred. In one patient shortly after initiation of the procedure, severe hypertension was noted; another patient developed post-RFA syndrome. In five of six lesions, there was no residual enhancement of the treated tumor. In one patient CT examination showed areas of residual enhancement of the tumor after treatment. Our preliminary results suggest that imaging-guided percutaneous RFA is effective for local control of AM, without major complications and with a low morbidity rate related to the procedure. Long-term follow-up will need to be performed and appropriate patient selection criteria will need to be determined in future randomized trials.

Image-guided radiofrequency ablation for adrenocortical adenoma with Cushing syndrome: outcomes after mean follow-up of 33 months

OBJECTIVES

To evaluate the feasibility, safety, and therapeutic effects of image-guided radiofrequency (RF) ablation used for the treatment of adrenocortical adenoma with Cushing syndrome.

METHODS

From February 2003 to May 2005, 4 consecutive patients with adrenocortical adenoma and Cushing syndrome received percutaneous RF ablation. All tumors were in the left adrenal gland, with a mean tumor size of 2.7 +/- 0.6 cm (range 2.0 to 3.5). The RF ablation was performed under real-time computed tomography fluoroscopic guidance. Technical success was defined as disappearance of tumor enhancement on contrast-enhanced computed tomography imaging acquired within 1 week after RF ablation. Clinical success was defined as improvement in serum cortisol and adrenocorticotropic hormone values and symptoms at the end of follow-up.

RESULTS

Tumor enhancement disappeared after initial RF ablation in 3 of 4 patients (technical success rate 75%). The fourth patient underwent a repeat RF ablation session 3 years later, resulting in eradication of tumor enhancement. Both the serum cortisol and adrenocorticotropic hormone levels returned to normal and the symptoms related to Cushing syndrome had disappeared at the end of follow-up (range 20 to 46 months, mean 33) for a clinical success rate of 100%. All tumors showed involution (2.2 +/- 0.3 cm) at the end of the study. No major complications occurred related to the procedures except for pneumothorax requiring chest tube placement for 3 days.

CONCLUSIONS

Using RF ablation for adrenocortical adenoma with Cushing syndrome is a feasible, safe, and promising treatment method in selected patients.

Adrenal metastases: CT-guided and MR-thermometry-controlled laser-induced interstitial thermotherapy

The aim of the study was to evaluate the feasibility, safety and effectiveness of CT-guided and MR-thermometry-controlled laser-induced interstitial thermotherapy (LITT) in adrenal metastases. Nine patients (seven male, two female; average age 65.0 years; range 58.7-75.0 years) with nine unilateral adrenal metastases (mean diameter 4.3 cm) from primaries comprising colorectal carcinoma (n = 5), renal cell carcinoma (n = 1), oesophageal carcinoma (n = 1), carcinoid (n = 1), and hepatocellular carcinoma (n = 1) underwent CT-guided, MR-thermometry-controlled LITT using a 0.5 T MR unit. LITT was performed with an internally irrigated power laser application system with an Nd:YAG laser. A thermosensitive, fast low-angle shot 2D sequence was used for real-time monitoring. Follow-up studies were performed at 24 h and 3 months and, thereafter, at 6-month intervals (median 14 months). All patients tolerated the procedure well under local anaesthesia. No complications occurred. Average number of laser applicators per tumour: 1.9 (range 1-4); mean applied laser energy 33 kJ (range 15.3-94.6 kJ), mean diameter of the laser-induced coagulation necrosis 4.5 cm (range 2.5-7.5 cm). Complete ablation was achieved in seven lesions, verified by MR imaging; progression was detected in two lesions in the follow-up. The preliminary results suggest that CT-guided, MR-thermometry-controlled LITT is a safe, minimally invasive and promising procedure for treating adrenal metastases.

Adrenal Neoplasms: CT-guided Radiofrequency Ablation—Preliminary Results

PURPOSE

To evaluate initial experience with radiofrequency (RF) ablation of adrenal neoplasms.

MATERIALS AND METHODS

Thirteen adrenal masses in 12 patients (bilateral metastases in one patient) were treated with computed tomography (CT)-guided percutaneous RF ablation. Eleven adrenal lesions were metastases (five from lung cancer, four from renal cell carcinoma, and two from melanoma); one lesion was a pheochromocytoma and one was an aldosteronoma. There were 10 men and two women (average age, 58 years; range, 40-77 years) in the study; average adrenal mass diameter was 3.9 cm (range, 1-8 cm). Average number of RF applications per adrenal mass was 2.7 (range, 1-5 applications); average time per application was 7.8 minutes (range, 4-13 minutes). An internally cooled single electrode was used in five sessions; an internally cooled cluster electrode was used in eight sessions.

RESULTS

Average follow-up was 11.2 months (range, 1-46 months). Eleven of 13 lesions were treated successfully with RF ablation after one session. Successful treatment was defined as lack of enhancement of the treated region on follow-up CT images and resolution of the biochemical abnormality in two patients. In two patients with large adrenal lesions (4 and 8 cm in diameter), enhancement of residual tissue was observed after one treatment session; this finding was indicative of residual tumor. One patient with thrombocytopenia that resulted from chemotherapy had a small hematoma, but no transfusion was required. No patient developed hypertension during the RF application. No patient with metastases had recurrent tumor at the treated site, and this lack of recurrence indicated effective local control; 11 patients had progression of metastatic disease at extraadrenal sites.

CONCLUSION

Preliminary data suggest that CT-guided RF ablation is an effective technique for local control of adrenal neoplasms.

Aldosteronomas: experience with superselective adrenal arterial embolization in 33 cases

PURPOSE

To evaluate the effectiveness and long-term follow-up results of superselective adrenal arterial embolization (SAAE) of aldosteronomas.

MATERIALS AND METHODS

Thirty-three patients with unilateral aldosteronomas were treated with SAAE. A 0.2-7.0-mL dose of high-concentration ethanol (HCE) was selectively infused into the feeding arterial branches of the aldosteronoma through a microcatheter by using a coaxial technique. Hormone, electrolyte, and blood pressure levels were evaluated after SAAE. The influence of background factors on SAAE success rate and the influence of age on hypertension in the patients in whom SAAE was successful were assessed with the Fisher exact test and a logistic regression model.

RESULTS

SAAE was successful in 27 (82%) of 33 patients. SAAE success rate was not influenced by sex, age, hypertension duration, family history of hypertension, adenoma site, type of ethanol used, or number of embolized arteries. The destructive effects of SAAE continued for the 6-94-month (mean, 45 months) follow-up period in all patients in whom SAAE was successful. In one patient, aldosteronoma recurred 15 months after SAAE and the second SAAE was successful. Blood pressure decreased in all 11 (100%) patients aged 45 years or younger and in eight (50%) of 16 patients older than 45 years (P =.008). Blood pressure decreased within 4 weeks after SAAE in 15 (79%) of these 19 patients. The rate of blood pressure reduction after SAAE decreased with increasing age, and the correlation was significant (P =.022). None of the 33 patients had severe complications.

CONCLUSION

SAAE with HCE is an effective therapy for aldosteronoma.

Application of transarterial embolization of renal artery in rabbits with experimental hydronephrosis

This study was performed to validate the procedure of transarterial embolization of the renal artery (TAE-RA) using iohexol-ethanol solution in rabbits with unilateral experimental hydronephrosis and to evaluate the embolized kidney and contralateral normal kidney using B-mode ultrasonography and color Doppler ultrasonography. Experimental hydronephrosis was induced at 17 days after ligation of unilateral ureter in 13 rabbits. Renal artery embolization was performed using selective catheterization in the hydronephrotic kidney of eight rabbits and electrocardiography, oxygen saturation, body temperature, pulse, and respiratory rate were within normal ranges during procedures. Iohexol-ethanol solution was used as embolic material. Average ethanol dose for renal artery embolization was 1.4 +/- 0.7 ml/kg. There were no rabbits expired after TAE-RA and no side effects associated with regurgitation of iohexol-ethanol solution. In color Doppler ultrasonographic findings, there was no blood flow into the embolized kidneys treated by TAE-RA, however, blood flow signal was found in hydronephrotic kidney not treated by TAE-RA. Ultrasonographically, the mean longitudinal length of the embolized kidney significantly decreased at 2 and 3 months after TAE-RA. No significant difference of resistive index values was found between contralateral normal kidney of rabbits treated by TAE-RA and contralateral normal kidneys of rabbits treated with nephrectomy. We may conclude that TAE-RA with iohexol-ethanol solution is a viable alternative to nephrectomy in rabbits with unilateral hydronephrosis.

Renal artery embolization with diluted hot contrast medium: an experimental study

PURPOSE

To evaluate the safety and efficacy of diluted hot contrast medium to embolize the renal arteries in a canine model.

MATERIALS AND METHODS

Transcatheter embolization was performed in 15 dogs (five dogs in each phase: I, II, and control). The diluted hot contrast medium was heated to 90 degrees C--100 degrees C and 30--60 mL were injected into a renal artery of each dog in phase I (optimization studies) and II (efficacy studies). In the control group, balloon inflation was performed without injection of diluted hot contrast medium. The temperature measurement was performed on one dog in phase I by temperature probe. Follow-up angiography was performed immediately (n = 15), at 1 week (n = 9), at 1 month (n = 9), and after 3 months (n = 5). All dogs were killed and kidneys were removed for histologic examination.

RESULTS

The procedure was performed successfully in all dogs. Follow-up angiography showed complete obstruction of the injected renal arteries in phases I and II. The microscopic findings showed acute full-thickness necrosis of the renal cortex and renal artery in phase I, and complete coagulative necrosis of the cortex, medulla, and intrarenal blood vessels in phase II. There were no histologic changes of renal veins, inferior vena cava (IVC), and aorta. There were nonspecific findings in the control group.

CONCLUSION

This preliminary experimental study suggests that diluted hot contrast medium may be a safe agent for renal ablation without thrombus formation in the renal vein or IVC.