Therapeutic embolization with long-term occluding agents and their effects on embolized tissues

Hylan gel composition for percutaneous embolization

Viscoelastic, pseudoplastic, radiopaque injectable hylan gel for percutaneous embolization was developed and evaluated by in vitro and in vivo tests. The embolization gel is composed of cross-linked hylan (hyaluronan, hyaluronate), tantalum, microcrystalline cellulose, hexamethonium chloride, and thrombin. Upon delivery through small-lumen catheters to the appropriate vascular site, the gel induces formation of a solid blood/gel coagulum. Results from animal studies (rat aorta, rabbit auricular artery) demonstrate that formation of complete and long-lasting arterial blockage is readily achievable without complications due to blood flow, partial vessel obstruction, uncontrolled polymerization, or movement of the gel or its components (specifically thrombin and hexamethonium chloride) into the circulation. Microscopic evaluation indicates that arterial occlusion initially occurs as a result of the injected gel and formed fibrin; at 7 weeks and beyond, arteries are occluded by injected gel, inflammatory cells and fibrosis (scar tissue).

Interventional neurovascular treatment of a giant intracranial aneurysm using platinum microcoils

A 70-year-old woman presented with symptoms of progressive cerebellar dysfunction due to mass effect from a giant, expanding, posterior fossa aneurysm arising from the distal vertebral artery. The aneurysm contained thrombus and had a broad-based neck. From a transfemoral approach, with the patient under local anesthesia, a 2.2 French microcatheter was guided through the vertebral artery and placed directly into the aneurysm. Six 5 x 15-mm platinum microcoils were deposited into the residual lumen of the aneurysm, resulting in complete thrombosis with obliteration of the aneurysm and preservation of the parent artery. Endovascular coil embolization therapy by interventional neurovascular techniques may provide a therapeutic alternative in the management of surgically difficult symptomatic intracranial aneurysms.

Balloon embolization of latrogenic aortocoronary arteriovenous fistula

A detachable latex balloon was used to occlude an iatrogenic aortocoronary arterio-venous fistula. The aim of providing retrograde myocardial perfusion was not achieved to any significant degree because of rapid recruitment of collateral venous routes to the coronary sinus. This may have implications for the effectiveness of deliberate grafting of the coronary venous system with proximal venous ligation, as has been recommended when the coronary arterial system is small and diffusely diseased.

Balloon dilation catheters

Catheter therapy has gained an important role in the treatment of congenital heart disease. The cumulative experience with vascular and valvular balloon dilations has demonstrated low mortality and morbidity with short-term results similar to surgery. Currently, balloon dilation is an accepted treatment for valvular pulmonary stenosis, distal pulmonary artery stenosis, recurrent coarctation, rheumatic mitral stenosis, congenital valvular aortic stenosis, and intra-atrial baffle obstruction. Except for patients at high surgical risk, balloon dilation of native coarctation is considered investigational at most institutions but accepted at others. No conclusive evaluation is yet possible for dilation of bioprosthetic valves and membranous subaortic stenosis. Individual pulmonary veins appear undilatable. Various devices are available for closure of extra- and intracardiac communications. Transcatheter closure of aortopulmonary collaterals and arteriovenous malformations is now well established at some centers. In selected patients, therapeutic embolization of surgical shunts can replace surgery. Transcatheter closure of the patent ductus arteriosus has become routine at some centers. Nonsurgical closure of atrial and ventricular septal defects has entered clinical trials, and preliminary results appear very promising. Blade atrioseptostomy and foreign body retrieval are well established. Improvement of existing procedures and implementation of new concepts will consolidate the role of catheter therapy in congenital and acquired heart disease.

Recanalization of spinal arteriovenous malformations following embolization

Recently, therapeutic embolization has been advocated as the treatment of choice for arteriovenous malformations (AVM's) of the spine. However, no study has established lasting benefit from this procedure or determined the incidence of recanalization, as occurs with cerebral AVM's. In this study, six patients were followed periodically after complete obliteration of their AVM's by particulate embolization was shown by immediate arteriography. The study group included three men (aged 59 to 72 years) with spinal dural arteriovenous (AV) fistulas and three women (aged 27 to 38 years) with intramedullary glomus-type spinal cord AVM's. The patients were treated by embolization with 100- to 1000-microns diameter polyvinyl alcohol particles. Clinical improvement, most commonly manifesting as increased lower-extremity strength, occurred in all patients after embolization. However, recurrent symptoms, including weakness, numbness, and urinary incontinence, occurred within 2 and 8 months in two of the three patients with dural AV fistulas and within 2 months in two of the three patients with glomus AVM's, prompting radiological reevaluation. Spinal arteriography revealed recanalization of the AV fistulas and spinal AVM's in five patients. Magnetic resonance (MR) imaging demonstrated a signal-void area caused by intramedullary AVM's. This area disappeared after embolic occlusion, but recurred after delayed recanalization, indicating restored flow through the AVM. Embolization provides only temporary treatment for many spinal AVM's. After embolic occlusion, delayed reassessment with arteriography and/or MR imaging is indicated, particularly if the symptoms persist or recur. Surgical excision of spinal AVM's provides the only therapeutic means to eliminate flow through the AVM permanently in most patients, and should be considered the treatment of choice when feasible.

Anaesthesia for closed embolisation of cerebral arteriovenous malformations

Cerebral arteriovenous malformation embolisation is a therapeutic, neuroradiological procedure involving injection of bucrylate glue into the nidus of the AV malformation to obliterate the abnormal vascular network. These procedures may involve significant risks, are often long and thereby necessitate the need for some form of sedation and for adequate monitoring of the cerebral, cardiovascular and respiratory systems. The anaesthetic management of a series of twenty patients undergoing embolisation of a cerebral arteriovenous malformation is outlined, seven general and nineteen neurolept anaesthetics being administered. Neurolept anaesthesia is the preferred technique as neurological assessment during the procedure is possible and complications may be diagnosed immediately. Systemic arterial hypotension may facilitate the embolisation process and various agents, including glyceryl trinitrate and sodium nitroprusside, have been employed for this purpose.

Longterm histopathologic follow-up of bronchial arteries after therapeutic embolization with polyvinyl alcohol (Ivalon) in patients with cystic fibrosis

We used light microscopy to examine, at autopsy, bronchial arteries in three patients with cystic fibrosis who died, respectively, 10, 16, and 28 months after bronchial artery embolization with barium sulfate-impregnated polyvinyl alcohol (PVA) to control hemoptysis. PVA was not identified beyond the midsegmental bronchus in any patient. Persistent focal fibrovascular occlusion was noted in two patients, and recanalized and/or partially obstructed vessels were associated with PVA in all. The histologic reaction to PVA included fibrosis, mild chronic inflammation, localized foreign body reaction, and, in two patients, focal calcification of PVA spicules. Within the inflammatory milieu were numerous macrophages containing BaSO4. Extensive vascular mural destruction and fibrosis associated with PVA were also observed. Both PVA and BaSO4 were also frequently present in the perivascular connective tissue. These findings indicate that, although longterm occlusion persists after therapeutic arterial embolization with PVA, focal recanalization also occurs. The extent of vascular mural injury following PVA embolization in humans has been previously underestimated by animal experiments. Finally, perivascular deposition of PVA represents a common reaction to diverse foreign body emboli in both systemic and pulmonary arteries.

The pathology of encephalic arteriovenous malformations treated by prior embolotherapy

A pathologic study was undertaken of seven encephalic arteriovenous malformations, including five resected from one to seven days after balloon embolization, one resected 10 days after embolization with polyvinyl alcohol foam (PVA), and a large mesencephalic AVM in a patient who died eight weeks after a series of embolization procedures with PVA and silicone spheres. AVM's resected 6-7 days following balloon embolization showed focal mural and adventitial inflammatory infiltrates and parenchymal (i.e. non-vascular) necrosis of a large portion of one AVM. The AVM examined 7 days post-balloon embolization showed an intraluminal thrombus containing refractile particles surrounded by foreign body giant cells (FBGC's). The AVM removed 10 days after PVA embolotherapy showed mural and perivascular necrosis with infiltration by polymorphonuclear leukocytes. The single autopsy case showed FBGC's surrounding residual PVA, refractile particles deep within vascular walls, and marked mural thickening of AVM channel walls, changes that may represent a response to previous angionecrosis and inflammation at the time of embolization. These findings, the pathogenesis of which is discussed in detail, may help to explain some of the rare complications of iatrogenic embolotherapy with these materials, as well as providing evidence for the basis of their efficacy.

Occlusion of experimental artery aneurysms by intrasaccular injection of fibrin sealant

Aneurysms were produced by grafting a vein pouch onto the cervical carotid artery of rabbits following the removal of an elliptical piece of the arterial wall. The diameter of the opening was 3-4 mm and the maximum height 8 mm. Through direct puncture of the aneurysm a clot of the fibrin sealant Tissucol was injected into the aneurysm. The sequential morphological changes were studied by light microscopy. One case was examined after 3 weeks by scanning electron microscopy. Complete resorption of the fibrin sealant was observed. The aneurysm cavity was filled with a dense connective tissue covered by a layer of newly formed endothelial cells.

Experimental aneurysms in the rabbit: occlusion by intrasaccular injection of fibrin sealant

Experimental aneurysms of the carotid artery were produced using the microsurgical technique of grafting a venous sack onto the artery in the neck of rabbits after the removal of an elliptical piece of arterial wall. Twenty-five aneurysms were occluded with the fibrin sealant Tissucol. Microscopic examination showed complete resorption of the fibrin clot and the formation of dense granulation tissue within the aneurysm, which was covered with a layer of endothelial cells after 2 weeks. The results are only tentative and require further experimental studies.

Failure of Ivalon to provide permanent hepatic arterial occlusion

Ivalon (polyvinyl alcohol) is a commonly used embolic agent, generally considered to be permanent. In a patient with the carcinoid syndrome, embolization of hepatic metastases with Ivalon failed to produce permanent occlusion, and recurrent tumor was supplied by many of the same small arteries identified on the original arteriogram. Occasionally, Ivalon may have only a temporary occlusive effect. A possible explanation for this phenomenon is proposed.

Arterial embolization for control of bleeding in advanced head and neck carcinoma

There are a number of patients with unresectable recurrent carcinoma of the head and neck who continue to lead a relatively functional life despite advanced local disease. For these patients bleeding from tumor represents a devastating complication that can abruptly terminate the course of an otherwise chronic disease, albeit a uniformly fatal one. The technique we describe renders a relatively safe and effective treatment that seems to control this problem. We report on our experience with three patients whose tumor bleeding was controlled by permanent intra-arterial embolization with Ivalon, a polyvinyl alcohol-based foam. The technique, indications, and complications are discussed.

Small particle polyvinyl alcohol embolization of cranial lesions with minimal arteriolar-capillary barriers

Polyvinyl alcohol foam, prepared as small particles measuring 70-150 micron when injected in intracerebral arteries of the rat, adhere to the vascular endothelium, allowing the particles to be captured without necessarily wedging intraluminally. Based on this observation, small particle microembolization was performed in a series of patients who had hypervascular cranial lesions, whose matrices angiographically appeared to have at best minimal arteriolar-capillary barriers. Each case was associated with intracranial dural sinus or cerebral venous drainage. In addition, several lesions had either venous ectasia or venous aneurysms. Symptomatic improvement occurred in all cases without apparent neurologic or pulmonary complications. These examples demonstrate the ability of very small polyvinyl alcohol foam particles to remain within the interstices of vascular lesions that display evidence of only minimal arteriolar-capillary barriers.

Cystadenoma with mesenchymal stroma (CMS) in the liver and bile ducts. A clinicopathologic study of 17 cases, 4 with malignant change

This study of 17 cases describes a homogeneous clinicopathologic group of tumors previously subsumed under the general term, hepatobiliary cystadenoma. This unique group of neoplasms that the authors have termed "cystadenoma with mesenchymal stroma" (CMS), occurred exclusively in women and showed two essential tumor components: a cyst lining of columnar to cuboidal, mucin secreting epithelium; and a moderately to densely cellular stroma composed of spindle (rarely oval) cells. The stromal element appeared similar to primitive mesenchyme, both on light and electron microscopic study, showing variable differentiation toward fibroblasts, smooth muscle, adipose tissue and capillaries. Cases of hepatobiliary "cystadenoma" in the literature with histology similar to CMS had similar sex and age incidences, while histologically dissimilar cases, lacking the mesenchymal stroma, had significantly different parameters. Four cases of CMS in this series showed malignant change that was manifested as papillary adenocarcinoma, suggesting the need for complete surgical removal of these premalignant neoplasms.

Morphological studies of human arteriovenous malformations. Effects of isobutyl 2-cyanoacrylate embolization

Ten patients with symptomatic arteriovenous malformations (AVM's) underwent embolization with isobutyl 2-cyanoacrylate (Bucrylate) delivered via a mini-balloon catheter according to the protocol of George and Pevsner. These patients underwent surgical removal of their embolized AVM, and surgical specimens were evaluated by light and scanning electron microscopy. Ten other patients with AVM's underwent surgical resection without prior embolization, and these surgical specimens were evaluated in a similar manner. Results from this study indicate that Bucrylate incites an inflammatory response characterized by foreign-body giant cells. This reaction was present as early as 3 weeks after embolization and persisted in specimens resected almost 1 year after the last embolization. No such reaction was observed in unembolized AVM's. Both light and scanning electron microscopy demonstrated a lattice structure of the Bucrylate embolus within the AVM vessels. These studies also demonstrated micro-channels within the Bucrylate embolus and the presence of what appears to be normal red blood cells within the latticework of the embolus. Vascular endothelium not in direct contact with the Bucrylate embolus retains a normal morphology as revealed by scanning electron microscopy.

The histotoxicity of cyanoacrylates. A selective review

Cyanoacrylates, a group of rapidly polymerizing adhesives, have found widespread uses in oral and general surgery as well as surgical subspecialties, for example as hemostatic and anastomotic agents. They have been utilized most recently as materials for embolotherapy of complex cerebral and extra-cerebral vascular anomalies. The histopathology that results from their deposition in human tissues is thus an important consideration, and the subject of this review. Particular attention is given to the fate of cyanoacrylates in cerebral lesions after iatrogenic embolization procedures. The apparent toxicity of these plastics on blood vessel walls is discussed in relation to experimental observations. It is imperative that clinicians who use this group of substances evaluate their potential functions in the light of the pathologic findings.

Renal arteriovenous fistula following nephrectomy

Three cases of postnephrectomy renal arteriovenous fistula are described. A review of the literature shows the rarity of this complication since only 62 cases (including the author's cases) are known. Reported cases have been recognized after intervals up to forty years. The major complication is cardiac failure. Surgical treatment gives satisfactory results, but nonsurgical closure has now become possible. Early diagnosis is easy by auscultation of the loin which constantly reveals a continuous bruit.

Embolotherapy in the treatment of congenital arteriovenous malformations of the hand: a case report

This article describes the treatment of a painful ulcerating congenital arteriovenous malformation in the hand of a 39-year-old woman. Preoperative transcatheter embolotherapy was used to diminish vascularity and engorgement. Operative treatment consisted of a resection of angiomatous material and coverage with a pedicle flap. Preoperative transcatheter embolization of small feeder vessels may offer some advantage over the operative approach alone in treating congenital arteriovenous malformations of the hand.

Intraarterial ethanol as a long-term occlusive agent in renal, hepatic, and gastrosplenic arteries of pigs

The renal, hepatic, or gastrosplenic arteries of eleven juvenile pigs were selectively injected intraarterially with 95% ethanol to evaluate its efficacy as an agent for use in permanent occlusion and infarction of the vascular bed supplied by the injected artery. A dose of 2.2 cc/5 kg (1 cc/5 lb) of 95% ethanol was injected over 30-45 sec. The animals were then killed at 1 to 91 days and all pigs demonstrated tissue infarction and vascular occlusion. Our results confirm that ethanol is an effective agent for the infarction of organs and that complications can result if catheter placement is not precise and normal tissue is inadvertently perfused.

Obliteration of experimental aneurysms in dogs with isobutyl-cyanoacrylate

Experimental cervical carotid aneurysms in dogs are obliterated with isobutyl-cyanoacrylate ( IBCA ) injected under direct vision into the aneurysm. Reflux of IBCA into the artery was prevented by inflating either a latex or a Silastic balloon in the carotid artery at the level of the neck of the aneurysm. This balloon was introduced through a catheter advanced into the common carotid artery by femoral catheterization. The Silastic balloon was found to be much more effective than the latex balloon in preventing spillage of IBCA into the lumen.

New occlusive agent for therapeutic embolization tested in dogs

A new occlusive agent, Vilan 500, was used to embolize the arterial bed of the kidney in 12 dogs. This polyvinyl acetate, alcohol-soluble agent becomes gelantinous on contact with an aqueous environment and its low viscosity makes this material well suited for application through small-caliber catheters. Complete arterial occlusion of the embolized kidneys was observed in all animals. On histologic examination of tissue 4-6 weeks after the procedure, changes were seen such as shrinkage through fibrosis, diffuse necrosis and atrophic parenchyma. No signs of recanalization of the embolized artery or functional collateral circulation were noted in any dog.

Transcatheter arterial embolization--major complications and their prevention

A thorough account is given of the complications of embolization techniques in nonneurovascular areas, including hepatic infarction, renal and splenic abscess formation. Infarction of the urinary bladder, gallbladder, stomach, and bowel are discussed. Suggestions are offered to prevent complications from embolization where possible. Specific agents for embolization are detailed and their relative merits are compared; ethyl alcohol has recently gained popularity for treating esophageal varices and infarcting renal tumors. Care is advocated when using alcohol in the renal arteries; employing this agent is currently contraindicated in the celiac and mesenteric arteries. Coils and balloon systems are also described along with their potential complications.

Embolization with "Ethibloc" of vascular tumors and arteriovenous malformations in the head and neck

"Ethibloc" has been used almost exclusively until now for embolization of tumors and bleeding vessels in the liver and kidney. Unlike with Gelfoam-particles, there is no recanalization. The resorption occurs so slowly that there is no interference with the necrosis of the embolized tumor. Due to its low viscosity, it passes catheters with thin lumina and fills the capillary bed of the tumor without danger danger of reaching the venous vessels. In this paper we describe a new technic of percutaneous catheter-embolization with Ethibloc using a coaxial catheter which we believe enhances safety and effectiveness. It has been successfully used in five patients. In the meantime two more patients have been treated successfully.

Embolization of cerebral arteriovenous malformations with bucrylate

Forty-six patients with cerebral arteriovenous malformations (AVM's) were selected for embolization with bucrylate. These patients were assigned to three different groups. Group I consisted of 22 patients with nonresectable AVM's who were selected for embolization with a Silastic calibrated-leak ballon. In 16 or these patients, embolization was achieved, with partial obliteration of the AVM in 14 and complete obliteration in two. Five patients had subarachnoid hemorrhage caused by the balloon bursting and concomitant dissection of the feeding vessel. Four of these patients recovered completely and one died of a brain-stem hemorrhage. A permanent field defect was noted in five cases, and two patients had a transient mild neurological deficit. Group II consisted of 13 patients treated by intraoperative embolization. Complete obliteration by embolization was obtained in four cases, and complete surgical resection after embolization in five. Partial embolization with no surgical resection was achieved in five cases. Three of these patients had a permanent mild neurological deficit and two had transient deficits. There was no mortality in this group. Group III consisted of 11 patients treated by embolization with bucrylate using a new latex calibrated-leak balloon. This balloon has a higher malleability, and takes on the exact configuration of the feeder, with no risk of dissection. This balloon also permits delivery of the faster and larger injection of bucrylate to the arterial feeders of the AVM. Two AVM's were completely obliterated, and embolization was only partially successful in the other cases. Neurological complications consisted of incomplete field defects in two cases, slight memory loss in one case, and transient clumsiness of the arm and face in one case. Two patients have a catheter permanently glued in the malformation, with no neurological complication. There was no mortality in this group.

Homologous controlled-viscosity fibrin for endovascular embolization. Part II: catheterization technique, animal experiments

Part I of the present paper described the development of a substance for endovascular embolization from homologous fibrinogen, aprotinin, thrombin, metrizamide and CaCl2. Part II deals with the applicability of a controlled-viscosity fibrin mixture via different types of arterial catheters. In a flow-dynamic model the embolizing medium injected via a double syringe was shown to block a blood flow corresponding approximately to the flow encountered in cerebral angioma vessels. In the course of animal experiments the embolization of mesenteric arteries of rabbits showed the distribution of the embolizing medium to be dependent on its viscosity; the action of an embolizing medium applied by means of a double syringe was studied in the femoral arteries of rabbits. Scintigraphy was used to study the distribution of the substance in the body of the experimental animal after intravenous (i.v.) application; long-term studies of embolized auricular arteries in rabbits revealed parchment-like necroses after 5 to 10 days and the presence of radiopaque substances in the ear stumps after 6 weeks.

Transcatheter hemostasis in the genitourinary tract

Transcatheter hemostasis is applicable in a large variety of causes of genitourinary hemorrhage. The method is particularly useful in the management of trauma since temporary occlusion of the bleeding vessel usually produces cessation of hemorrhage without significant sacrifice of additional parenchyma. Control of arteriovenous fistulas requires an assessment of flow characteristics and careful tailoring of catheter and embolization technique; large emboli or glue is frequently required for occlusion of large fistulas, whereas small ones can be treated with Ivalon. Hemorrhage from renal or pelvic neoplasm is also effectively managed by transcatheter therapy.

Pathology of arteriovenous malformations embolized with isobutyl-2-cyanoacrylate (bucrylate). Report of two cases

There is controversy as to the possible toxic effects of isobutyl-2-cyanoacrylate (bucrylate) when this substance is used for purposes of therapeutic embolization. Two cases are presented in which cerebral arteriovenous malformations were resected, one 42 days and the other a year after bucrylate embolization. In both, pathological examination revealed a brisk intimal foreign-body giant-cell reaction wherever bucrylate was present in a vessel, along with chronic inflammation in the vessel walls and adjacent brain parenchyma. The findings are discussed in the light of other observations on the histotoxicity of bucrylate.

Massive hemoptysis: control by transcatheter bronchial artery embolization

Massive hemoptysis (600 ml in 48 hours) has an ominous prognosis with a mortality of 50 to 100% in medically treated patients and up to 35% in patients undergoing operation. Surgical resection has been the procedure of choice in patients with massive hemoptysis. Those with a contraindication to operation present a particularly frustrating problem. We have treated 7 such patients with massive hemoptysis by transcatheter bronchial artery embolization. In all 7, the bleeding was arrested. Two patients died of recurrent hemoptysis, 1 ten days and the other 2 months following embolization, and 5 are well 1 month to one year later. Transcatheter bronchial artery embolization is a valuable therapeutic modality in patients with massive hemoptysis. However, the procedure is palliative, and, therefore, elective resection must be considered as definitive treatment in those patients who have no contraindication to operation.

Studies of GI bleeding with scintigraphy and the influence of vasopressin

The management of patients with gastrointestinal (GI) bleeding depends on accurate localization of the site of hemorrhage. Endoscopy and arteriography, although successful in achieving this goal in the majority of patients, are invasive and have other shortcomings. The introduction of the 99mTc-sulfur colloid technique has greatly simplified the evaluation and management of these patients. This test is useful in detecting and localizing the bleeding site in the lower GI tract. Scintigraphy is now used as the initial study of choice in patients with rectal bleeding. Advances made in angiography and nuclear medicine techniques also have resulted in improved management of patients. Conservative approaches succeed in controlling hemorrhage in most patients. Vasopressin is the most widely tested agent and has been adopted by many as the preferred preparation for this purpose. Before the introduction of the 99mTc-sulfur colloid technique, angiography was used to monitor the effectiveness of this drug, whether administered intravenously or intraarterially. With the use of scintigraphy and intravenous administration of vasopressin, these patients now can be managed noninvasively. Only when the intravenous Pitressin infusion fails to stop hemorrhage, is the intraarterial approach considered. Surgery is used as a last resort when these measures fail to stop the bleeding.

Transcatheter vessel occlusion: selection of methods and materials

Transcatheter vessel occlusion (TCVO) is increasingly used for control of hemorrhage, palliative and preoperative tumor embolization, organ function ablation, and obliteration of arteriovenous fistulae and malformations. Methods for TCVO include transcatheter electrocoagulation, "staining" with contrast, the use of balloon-tipped catheters, and embolization. The choice of method and material depends on whether proximal occlusion of feeding vessels or arteriocapillary occlusion is desired, the vascular anatomy of the lesion, the safety with which the lesion can be embolized, and the type of lesion being treated. Embolization is the most frequently employed modality. Available materials include autologous tissue, absorbable hemostatics, synthetic particulates, and liquid polymers. Each material has advantages and disadvantages that make it desirable in certain situations and less useful in others. Complications of TCVO may be disastrous, but can be avoided with careful attention to detail. The specific features of the lesion determine the choice of materials and techniques.

Therapeutic embolization with detachable balloons

In our first 18 months' clinical experience with embolization in the chest and abdomen using detachable balloons, successful results were obtained in 34 of 38 patients. One and 2-mm detachable silicone balloons, which can occlude vessels 4--8 mm in diameter, were employed. Prolonged balloon inflation was routinely achieved using iso-osmotic iodipamide meglumine as the filler and limiting inflation volumes to experimentally determined maximums. Improvements in introducer catheter design simplified delivery of the balloon into a variety of circulations. Detachable balloons are not suitable for all embolization purposes, and they are frequently used in conjunction with other agents. When used properly, balloons produce a permanent occlusion that is extremely selective and potentially reversible up to a certain point in the procedure. The balloon technique enables the angiographer to occlude vessels at distances of 2--10 mm beyond the introducer catheter, thus avoiding the need for subselective catheterization and minimizing the dangers of inadvertent embolization.

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.

Treatment of traumatic renal arteriovenous fistulas by detachable silicone balloon embolization

A new technique of detachable balloon arterial embolization allowed non-operative occlusion of 2 patients with post-traumatic arteriovenous fistulas in the kidney. This approach was successful in controlling hemorrhage with minimal loss of renal tissue.

Meyenburg complexes of the liver and bile cysts as a consequence of hepatic ischemia

Meyenburg complexes and simple bile cysts are described in a patient having polyarteritis nodosa with involvement of the intrahepatic arterial tree. Similar lesions are found in the liver of monkeys subjected to experimental occlusion of the peripheral hepatic arterial tree. It is proposed that a pathogenetic mechanism conducive to the formation of Meyenburg complexes may be hepatic ischemia.