Intraluminal obliteration of the renal arteries in kidney tumors

New biocompatible highly purified collagen gel for therapeutic renal artery embolization

OBJECTIVES

To evaluate the effectiveness and safety of a new purified collagen gel with specific properties for renal artery embolization in an experimental model in dogs.

METHODS

The new gel was prepared from type I bovine tendon collagen, highly purified to eliminate immunogenicity, and reconstituted through extensive dialysis in distilled water without the addition of glutaraldehyde. The study was conducted on 16 mongrel dogs that underwent random embolization of the renal artery. The dogs were divided into two groups: group 1 was killed after 2 days and group 2 after 21 days. The abdominal organs, lungs, and muscles of the posterior limbs were studied in detail and samples were taken for an anatomic-pathologic analysis.

RESULTS

After embolization, uniform parenchymatosus ischemia and loose perirenal adhesions without significant volumetric changes were observed in group 1. A microscopic study revealed acidophilus amorphous and birefringent emboli filling the lumen of the renal artery and extending into the arterioles. The glomeruli and tubules showed early signs of diffused necrosis. In group 2, microscopic examination revealed endothelial proliferation around the emboli that had closely adhered to the arterial wall, with signs of fibroblastic proliferation within the emboli. In both groups, the abdominal organs, lungs, and muscles of the posterior limbs did not show signs of collagen migration.

CONCLUSIONS

Purified collagen gel effectively embolized the renal artery. The absence of collagen migration to other organs and posterior limbs suggests that this material can be safely used for organ embolization.

Renal Embolization: Feasibility of Magnetic Resonance-Guidance Using Active Catheter Tracking and Intraarterial Magnetic Resonance Angiography

RATIONALE AND OBJECTIVES

Magnetic resonance (MR)-guidance of endovascular interventions offers various advantages, including the absence of ionizing radiation, excellent soft tissue contrast, and multiplanar and functional imaging capabilities. The objective of this study was to assess the feasibility of MR-guided renal embolization using active catheter tracking with automatic slice positioning and intraarterial contrast-enhanced MR angiography (MRA).

MATERIALS AND METHODS

MR-guided embolization of 16 kidneys was attempted in 15 pigs using real-time tracking of active 5-Fr. catheters. Embolization was monitored by selective intraarterial projection MRA. Intraarterial three-dimensional (3D) MRA was used for the assessment of embolization results. Additional pathologic correlation was available in 2 animals. The image quality of intraarterial 3D contrast-enhanced-MRA was rated by an independent radiologist who was not involved in the animal experiments.

RESULTS

Active catheter tracking with automatic slice positioning allowed reliable catheter guidance and catheterization of the renal artery in all animals. Embolization was successful in all kidneys (11 left, 5 right), as verified by intraarterial 3D contrast-enhanced MRA (ce-MRA) and/or pathology. The image quality of intraarterial 3D ce-MRA was rated excellent in 10 animals, moderate in 4 animals, and poor in 1 animal.

CONCLUSION

Renal embolization using active catheter tracking and intraarterial ce-MRA is feasible. Selective intraarterial ce-MRA allows the assessment of blood supply and organ perfusion before, during, and after therapeutic interventions, thereby complementing MR-guided endovascular interventions.

Prolonged survival following palliative renal tumor embolization by capillary occlusion

Nine patients with renal cell carcinoma and severe hematuria were palliatively treated with a new type of angioocclusion: the concept of capillary embolization. The so-called occlusion gel Ethibloc was used as embolizing agent. Each patient was followed up until death or for at least 4 years. All patients had a stage T3 or T4 tumor, 3 patients had metastases to multiple organs, 3 had lung metastases, and 3 were free of metastatic disease. In all cases, very high volumes (14-40 ml) of the embolizing agent were necessary to achieve total occlusion of the entire arterial compartment. Patients without metastatic disease had a mean survival time of 6 years and 4 months, all of them without signs of malignant disease. Patients with metastases had a mean survival time of 3 years. Compared with the natural history of renal cell carcinoma treated otherwise, this represents a substantial prolongation of survival time. Contrary to other angioocclusive treatment modalities, the concept of capillary occlusion with Ethibloc seems to achieve total tumor destruction.

Morphology of regressive changes in the kidney following experimental ischaemia

Total or partial renal ischaemia was studied in rats and pigs in a series of experiments, after total devascularization (ligature of renal vessels and ureter); ligature of isolated renal artery; experimental embolization of renal artery by non-resorbable material; devascularization of a specific renal segment by deep, strangulating sutures. Morphological studies showed that the resulting necrotization is represented most frequently by coagulation necrosis, less frequently by colliquating necrosis. Occlusion of the renal artery by embolization or ligature leads only to partial necrotization or atrophy. Total devascularization of the renal hilus or total devascularization of a specific renal segment by strangulating sutures leads to total destruction of the devascularized (devitalized) tissues. Within 8-12 weeks, the whole organ changes into a small residue of connective tissue. The possibility of the use of the devascularization technique in the treatment of tumours is discussed.

Combined transcatheter arterial embolization and regional chemotherapy for locally advanced carcinoma of the breast. A preliminary investigation

Seventeen patients with carcinoma of the breast received a combination of transcatheter arterial embolization and regional chemotherapy before surgery. A gelatin powder mixed with an anticancer agent and blood clotting factors (own technique) was selectively injected into the internal mammary artery, the lateral thoracic artery, and the thoracodorsal artery. Marked regression of both primary tumor and metastatic regional lymph nodes was observed. The potential of this method as presurgical treatment is discussed.

Renal disease in the geriatric patient

Although there are physiologic and anatomic changes of the kidney that occur almost universally with aging, no specific kidney disease that is totally confined to the geriatric population has been identified. Kidney diseases that predominate in the elderly include vascular and atheroembolic diseases, obstructive nephropathies, nephropathies secondary to certain systemic diseases, and intrinsic kidney disease. An understanding of the age-related changes of renal architecture and function is necessary to distinguish them from actual diseases that affect the aged kidney. These changes and their probable consequences for the geriatric patient are reviewed. We then discuss particular aspects of renal diseases that occur more commonly or have unique age-related manifestations in the elderly.

Hypertension with renal carcinoma. An effect of arterial embolization

A patient presented with mediastinal metastases from renal adenocarcinoma. Palliative therapy included Gelfoam and steel coil embolization of the right renal artery. Six weeks later he was found to have developed severe hypertension. Arteriogram revealed collateral vessels which supplied the tumor; the renal vein renin activity was four times higher on the right than on the left. We suspect that infarction of the kidney was not complete because of collateral arterial supply, and renin-dependent hypertension was the result. Thus, it may be hazardous to embolize large hypernephromas without subsequent nephrectomy.

Preoperative embolization of renal tumours using balloon catheters

Preoperative embolization was used in a series of 13 patients for reducing the bleeding during operation of even very large renal carcinomas. During and after embolization pain occurred which necessitated treatment. Balloon catheter embolization was used which excludes the risk of reflux of embolizing material to the aorta. It caused none or only minor injury to the renal arterial wall. No serious complication occurred.

Usefulness of preoperative transcatheter embolization in kidney tumors

In recent years preoperative transcatheter embolization has been used widely in the management of kidney tumors. However, the effective clinical usefulness of this method has not yet been proved. Forty cases of kidney tumors treated by preoperative embolization and radical nephrectomy are reviewed and compared with a homogeneous group of patients who did not undergo preoperative embolization. Intraoperative blood loss, postoperative complication, and survival rate were statistically evaluated according to tumor stage. Advantages and disadvantages of preoperative transcatheter embolization of kidney tumors are reviewed.

New indications for renal infarction

Two patients with stage D transitional cell carcinoma of the kidney presented with recurrent massive hematuria. Both had prompt cessation of bleeding following renal infarction. Another patient had malignant hypercalcemia related to metastatic renal cell carcinoma and became normocalcemic after renal infarction. Angiographic renal infarction offers a rational alternative to conventional therapy in the management of these 2 problems.

Transcatheter arterial chemoembolization of renal cell carcinoma with microencapsulated mitomycin C

Ethylcellulose microcapsules of mitomycin C were prepared for intra-arterial use in an attempt to enhance the antineoplastic effects of mechanical arterial embolization. The potential therapeutic effects of intra-arterial mitomycin C microcapsules were considered to be a function of microembolization and prolonged drug action, that is chemoembolization. A total of 33 patients with renal cell carcinoma was subjected to transcatheter arterial chemoembolization with mitomycin C microcapsules supplemented with gelatin sponge, and 10 patients were subjected to chemoembolization with non-encapsulated mitomycin C and gelatin sponge. Comparative studies on objective tumor decrease, angiographical findings and histological effects between the 2 treated groups indicated that mitomycin C microcapsules definitely enhanced the therapeutic responses to gelatin sponge embolization. Bioassay of the peripheral blood revealed that intra-arterial mitomycin C microcapsules reduced markedly mitomycin C levels in the blood compared to non-encapsulated mitomycin C, leading to a decrease in hematological toxicity. The results may prove that chemoembolization with mitomycin C microcapsules is effective as a preoperative and palliative measure in the treatment of renal cell carcinoma.

Complications of the Gianturco coil in preoperative infarction of renal cell carcinoma

Percutaneous artery occlusion has been described for a multitude of clinical problems, including preoperative infarction of the kidney for renal cell carcinoma. The Gianturco wool coil provides a relatively new method for occlusion. Few complications with this device have been reported. We describe our experience with complications in 3 patients and discuss methods of their prevention.

Embolization for genitourinary disorders

Fourteen patients with various genitourinary disorders underwent arterial embolization. The procedure was useful in facilitating surgical removal of hypernephromas, in decreasing tumor-induced hypercalcemia, and in diminishing proteinuria secondary to renal failure. Patients with priapism due to excessive arterial inflow responded well. Results of embolization performed because of bleeding varied. When bleeding was localized to a single vessel or to an area supplied by such a vessel, embolization was successful. However, when hemorrhage was diffuse or due to multiple vessel inflow, arterial embolization was not entirely effective.

Renal metastasis of adenocarcinoma of the lung: massive hematuria managed by therapeutic embolization

The rare complication of massive hematuria secondary to metastatic infiltrating adenocarcinoma of the lung to the kidney was managed with steel coil therapeutic embolization. The angiographic and pathologic picture as well as the advantages of this therapeutic modality in this clinical setting are discussed.

Preoperative renal embolization as adjunct to radical nephrectomy

Radical nephrectomy preceded by preoperative renal artery embolization using Gianturco-Anderson-Wallace steel coils has objective value as determined by comparing records of 15 patients who had adjunctive embolization with 15 patients who did not. Embolization of the major renal artery facilitated surgery allowing initial renal vein ligation resulting in reduction of blood loss and operative time. The described experience and current literature review support adjunctive embolization and document minimal risk to the patient.

Transcatheter arterial embolization in urological tumors: the use of isobutyl-2-cyanoacrylate

Transcatheter arterial embolization is a useful technique to manage urological tumors. Herein we describe a new embolic material (isobutyl-2-cyanoacrylate) in 5 cases of renal cancer embolization and in 1 case of bilateral hypogastric embolization for bladder cancer hemorrhage. Isobutyl-2-cyanoacrylate provides a complete, distal and irreversible embolization, making it suitable material in cancer embolization.

Preoperative angiographic embolization for large hemorrhagic Wilms' tumor

Preoperative angiographic embolization of the renal artery is a surgical adjunct not necessary for the majority of Wilms' tumors. However, on the basis of early experience, we would recommend this technique for those large vascular tumors with preoperative hemorrhage in which the risk of embolization is likely to outweight the risk of intraoperative disruption and hemorrhage.

Angiographic infarction of a large hypernephroma with a tissue adhesive for control of hematuria

A case of a large inoperable hypernephroma in a 69-year-old man is presented. Recurrent life-threatening hematuria was controlled successfully by transcatheter embolization and infarction of the tumor using a tissue adhesive called isobutyl 2-cyanoacrylate. The patient remained without hematuria for 18 months until death from extensive metastatic diseases. The advantages and disadvantages of tissue adhesive as an embolization material are discussed.