Interventional radiology in the treatment of high-flow renal arteriovenous fistulas. Report of two cases

PURPOSE: To describe the morphological and haemodynamic characteristics of high-flow idiopathic renal arteriovenous fistulas and the radiological treatment techniques. MATERIALS AND METHODS: Two cases of idiopathic renal arteriovenous fistula were treated with transcatheter embolization. In the first case, the anomalous arteriovenous communication was embolized with acrylic glue through the afferent artery while the efferent vein was temporarily occluded with a balloon catheter using the "stop flow" technique. In the second case, the fistula was occluded from the arterial side using Gianturco coils and the "free flow" technique. RESULTS: In both cases post-procedural angiography demonstrated occlusion of the fistula. A color-Doppler US examination 6 months later showed the regularization of flow parameters in the renal artery and vein. Angiographic follow-up showed occlusion of the arteriovenous fistula, regularization of the renal artery calibre and normal renal parenchymal flow. CONCLUSIONS: Embolization is the best treatment for rare, high-flow, renal arteriovenous fistulas. The "stop flow" technique with acrylic glue is fast and economical. The "free flow" technique with coils is more expensive and complex, but just as effective.     

Percutaneous Transcatheter Embolization of a Large Pulmonary Arteriovenous Fistula with an Amplatzer Vascular Plug

Percutaneous transcatheter embolization has become the treatment of choice for pulmonary arteriovenous fistulas (PAVFs), in most cases replacing surgical intervention. However, while "classic" devices, such as intravascular coils and detachable balloons, have proved to be successful for interventional occlusions of small or medium-sized PAVFs, they are not ideal in larger fistulas because of the risk for embolization to the systemic circulation. We describe the case of a 61-year-old woman with a symptomatic huge solitary pulmonary arteriovenous fistula (4.5 cm in diameter), occupying part of the lung in the lower right lobe with two feeding arteries (10 and 4 mm in diameter, respectively), who underwent successful transcatheter closure with an Amplatzer Vascular Plug, a new device designed for the occlusion of vascular abnormalities.     

Pseudoaneurysm and renal arteriovenous fistula after nephrectomy: two cases treated by transcatheter coil embolization

Pseudoaneurysms and arteriovenous fistulas of renal arteries are rare clinical lesions. Invasive renal procedures may lead to pseudoaneurysm or arteriovenous fistulas (AVFs). We report two pseudoaneurysms and arteriovenous fistula cases that were treated by transcatheter embolization with metallic coils. The first case is left main renal artery pseudoaneurysm after nephrectomy in a patient with a solid renal tumor. The second case is right main renal artery AVF with giant pseudoaneurysm after both gunshot injury and nephrectomy. On the basis of color Doppler sonography and computed tomography (CT) findings, cases were diagnosed as pseudoaneurysm after nefrectomy. Contrast-enhanced CT scans showed a hyperdense area within the hematoma consistent with pseudoaneurysm. Endovascular treatment with coil embolization succeeds to total occlusion in renal artery pseudoaneurysm. Delayed hemorrhage related to postnephrectomy may be life-threatening conditions because of diagnostic difficulties. AVF and pseudoaneurysm can be treated safely and successfully by transcatheter arterial embolization.     

Arteriovenous fistulas complicating biopsy of renal allografts: treatment of bleeding with superselective embolization

The use of superselective embolization was assessed as a treatment for bleeding from postbiopsy arteriovenous fistulas (AVFs) in renal transplants. AVFs commonly occur after biopsy procedures in renal transplants, but severe bleeding is rare. Transcatheter embolization can be used to control bleeding, but unless it is sufficiently selective, the procedure results in loss of significant amounts of renal parenchyma. During a 4-year period, embolization procedures were attempted in seven patients 30-65 years old. All had AVFs shown on arteriography. Five patients underwent embolization; occlusion occurred only in the branch supplying the AVF. In one patient with three large AVFs, two were found to have occluded the day after embolization was attempted. In another, an AVF occluded when superselective catheter position was achieved but before embolization. Catheter manipulation in these cases may have precipitated occlusion. In five cases, coaxial embolization techniques were used. Embolization materials consisted of coils in three cases: 0.038 in. (0.97 mm) in one case, 0.025 in. (0.64 mm) in one case, 0.018 in. (0.46 mm) in one case; 0.038 in. (0.97 mm) coils and gelatin foam particles in one case; and localized contrast extravasation in one case. Serum creatinine level was measured before and after embolization in all patients, and radionuclide studies were undertaken in three cases. In all patients, bleeding was effectively controlled. None of the patients showed an increase in serum creatinine level after embolization, and in four, significant improvement was seen. Nuclear medicine studies showed no loss of renal function and a dramatic improvement in one patient. No complications due to the procedure were seen. Our experience suggests that superselective embolization with coaxial catheter techniques is an effective method of treating bleeding from postbiopsy AVFs in renal transplants with minimal loss of renal parenchyma.     

Management of post-biopsy renal allograft arteriovenous fistulas with selective arterial embolization: immediate and long-term outcomes

AIM: To evaluate the outcomes after transcatheter embolization of percutaneous biopsy-related arteriovenous fistulas in renal allografts. MATERIALS AND METHODS: All post-biopsy renal-transplant vascular injuries referred for embolization between June 1999 and October 2006 were reviewed retrospectively. There were six male and six female patients with a mean age of 49.8 years (range 25-67 years); nine patients were symptomatic, three asymptomatic. Colour Doppler ultrasound (CDUS) and angiography showed one intra-renal arteriovenous fistula in 10 patients and two in two patients, combined with a pseudoaneurysm in six patients. Superselective embolization using a single catheter or coaxial microcatheter was performed with 0.035' coils or 0.018'microcoils, respectively, in all 12 cases. 24-h creatinine clearance values before (the day of biopsy) and after (7-14 days; 3 months) the procedure were compared using the Wilcoxon signed-rank test. Physical examination and CDUS were performed after 1, 6, and 12 months, and yearly thereafter. Mean follow-up was 33.6 months. RESULTS: Complete definitive occlusion of the fistula was achieved consistently with a single procedure. No procedure-related complications occurred. Renal infarction was minor in all patients (0-10% in nine and 10-20% in three). Symptoms resolved completely. Creatinine clearance values obtained before and after embolization were not statistically different (p=0.168;.889 respectively). No late recurrences were reported. CONCLUSION: Transcatheter embolization with coaxial or single-catheter techniques was effective and safe for treating post-biopsy arteriovenous fistulas in renal transplants. The loss of renal parenchyma was minimal and no mid-term deterioration of allograft function was noted. The long-term survival of the renal allograft seemed to be not affected by embolization.     

Successful embolization of a renal arteriovenous fistula; a feared kidney biopsy complication

The authors report a case of a 57-year-old woman who was successfully treated with a percutaneous embolization procedure for a renal arteriovenous fistula that developed as a complication of a kidney biopsy. An acute kidney injury that failed to resolve with medical management prompted further investigation with a renal biopsy. Five hours after the kidney biopsy, the patient became hemodynamically unstable with a blood pressure of 77 of 52 mm Hg. A stat abdominal computed tomography scan without contrast discovered a large left-sided perinephric hematoma that measured up to 11.5 cm with a moderate amount of perinephric blood. An angiogram subsequently demonstrated the presence of an arteriovenous fistula at the inferior pole of the left kidney. Several 2 × 3 mm and 3 × 3 mm coils were deployed into two separate segmental branches of the inferior pole, and the post embolization angiogram confirmed resolution of the previously visualized arteriovenous fistula.     

Transarterial embolization of a direct carotid cavernous fistula with Guglielmi detachable coils.

Four patients underwent transarterial embolization of a carotid-cavernous fistula with Guglielmi detachable coils; in three cases as the initial form of treatment and in one case after treatment via transarterial balloon embolization failed. The fistulas were 2 to 3 mm in diameter on pretreatment angiograms. Complete obliteration was achieved in two patients; in the other two, minimal residual flow remained immediately after embolization but disappeared by follow-up angiography. One to four coils were used to occlude the fistulas. The internal carotid artery remained patent in all patients, and there were no complications.     

Displacement of coils into the lung during embolotherapy: clinical importance and follow-up with helical CT

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the clinical importance and computed tomographic (CT) appearance of coils displaced into the lung during embolotherapy. MATERIALS AND METHODS: The authors retrospectively studied clinical charts and serial chest images from 25 consecutive patients after coil embolization. Chest radiography was performed in all patients, whereas helical chest CT was performed only in patients in whom dislocated coils were visible on chest radiographs. Coils were applied for the treatment of peripheral arteriovenous (AV) malformations and fistulas (n = 9), renal AV malformations or fistulas (n = 8), and primary or secondary tumors (n = 8). Clinical charts were analyzed for short- and long-term symptoms; chest radiographs and CT scans were reviewed for signs indicative of pulmonary infarction. RESULTS: None of the patients had clinical symptoms suggestive of pulmonary infarction. In two of the 25 patients (8%), displaced coils were seen in the pulmonary vasculature at chest radiography; these patients had been treated for renal AV fistula and peripheral AV fistula, respectively. One patient had two coils in the left hemithorax (upper and lower lobe), and the other patient had two coils in the right hemithorax (middle lobe). Neither of the patients had abnormalities suggestive of pulmonary infarction at helical CT. CONCLUSION: Chest radiography can help confirm the presence of coils displaced to the pulmonary vasculature during embolotherapy. Helical CT can also help rule out the presence of coil-associated pulmonary infarction.     

Embolization of Iatrogenic Vascular Injuries of Renal Transplants: Immediate and Follow-Up Results

Purpose: To evaluate the outcome in seven patients in whom iatrogenic vascular complications were treated with catheter embolization. Methods: Angiography showed an arteriovenous fistula in six of the seven patients, a pseudoaneurysm in three patients, and an arteriocaliceal fistula in three patients. Embolization was performed with GAW coils or microcoils in all cases. In three patients enbucrilate, polyvinyl alcohol, or absorbable gelatin powder was administered as an adjunct to the coils. Results: Angiographic success with total occlusion of the vascular injury was achieved in five of the seven patients and clinical success was achieved in four of seven cases. In two cases, nephrectomy after embolization was necessary because of renal artery occlusion or acute hemorrhage at the renal artery anastomosis, respectively. Infarction of 30%–50% of the renal parenchyma was seen in two cases. Conclusion: Angiographically successful embolization is not necessarily associated with clinical success. The complication rate is high.     

Interlocking detachable platinum coils,a controlled embolization device: Early clinical experience

Purpose: To present the early clinical experience of a new mechanically controlled-release embolization device<+>—<+>the interlocking detachable coil (IDC)—in complex embolization outside the head. Methods: IDCs were used only when conventional embolization techniques were considered too risky or unsafe. The coils consist of unfibered coiled platinum (0.012 inch), mechanically connected to a pusher wire and deployed through a Tracker 18 catheter. IDCs come in a range of diameters (2<+>–<+>8 mm) and lengths (1<+>–<+>30 cm). Results: A total of 87 IDCs were used for 27 procedures in 25 patients (mean 14.5 years) to occlude 31 arteries or vascular lesions. Control of the coil and its release were satisfactory and all coils were fully retrievable up to the point of deployment. Two IDC coils embolized inadvertently but were retrieved; there were no other complications. The IDC coils could not be satisfactorily placed in one high-flow arteriovenous (AV) fistula, and in another case there was a small residual fistula. Occlusion was produced in 29 of 31 lesions. Ancillary techniques were needed in 5 patients: temporary balloon occlusion in 2 and 0.038-inch coils in 3. Conclusion: The IDC coil is an effective device that allows controlled embolization to be performed, especially in aneurysms and in high-flow AV fistulas in children.     

Selective Embolization of Large Symptomatic Iatrogenic Renal Transplant Arteriovenous Fistula

We report on the successful treatment of hypertension by occlusion of a large iatrogenic renal transplant arteriovenous fistula using detachable embolization coils with concomitant flow reduction by occlusion balloon in two patients.     

Efficacy and Safety of Transvenous Embolization of Type II Renal Arteriovenous Malformations with Coils

PurposeTo evaluate the efficacy and safety of transvenous coil embolization of the venous sac for type II renal arteriovenous malformation (AVM).Materials and MethodsA retrospective review was conducted of 8 patients (5 women and 3 men; mean age, 57 years; age range, 41–69 years) who underwent transvenous coil embolization for type II congenital renal AVM at 5 different hospitals between 2012 and 2018. Additional intra-arterial ethanol injection was performed if shunt flow persisted after venous sac coiling. Technical success was defined as complete occlusion of shunt flow with coil embolization. Clinical success was defined as no symptom recurrence during the follow-up period. The renal parenchymal infarction rate was measured on computed tomography (CT), and procedure-related complications were reviewed.ResultsNine sessions of embolization were performed for 8 patients. The mean venous sac size was 24 mm (range, 10–39 mm), and a mean of 14 micro and/or micro-detachable coils (range, 3–50) were used. The technical success rate was 88% (7 of 8) using coil embolization. One patient (12%) required additional ethanol injection to complete occlusion of the shunt flow and had a less than 10% parenchymal infarction on follow-up CT. No procedure-related complications or recurrences occurred during a mean clinical follow-up period of 20.8 months (range, 4.7–76.6 months).ConclusionsTransvenous coil embolization of type II renal AVM showed an 88% technical success rate. One patient (12%) showed less than 10% renal parenchymal infarction after additional ethanol injection. No additional complications or recurrences occurred during the follow-up period.     

Embolization of renal vascular lesions: Clinical experience with microcoils and tracker catheters

After biopsy (n=6) and nephrostomy (n=1) of three native and four transplanted kidneys, gross hematuria, hypertension, and deterioration of function necessitated performance of transarterial embolization. Angiography revealed five arteriovenous fistulas (AVFs), one pseudoaneurysm, and one arteriocaliceal fistula. Superselective catheterization was accomplished using 5 Fr standard diagnostic catheters and 3 Fr coaxial Tracker catheters. Four of five AVFs were embolized successfully by inserting unfibered (2 patients) and fibered (2 patients) platinum coils (diameters 2 mm and 4 mm, respectively). For one AVF, additional injection of butylcyanoacrylate was necessary. The pseudoaneurysm was embolized successfully by such injection, and the arteriocaliceal fistula was occluded using one unfibered 2-mm coil. Embolization stopped the bleeding in all patients. One week after treatment, renal function was improved in 5 patients and remained unaffected in 2. Superselective embolization using Tracker catheters and fibered microcoils is an effective, safe treatment of renal vascular lesions.     

Staged endovascular occlusion of giant idiopathic renal arteriovenous fistula with platinum microcoils and silk suture threads

Large symptomatic aneurysmal renal arteriovenous (AV) fistulas usually present with a flank bruit, uncontrolled hypertension, and high-output cardiac failure. Traditionally, these have been treated surgically because of the risk of inadvertent pulmonary embolism with use of embolization techniques. The authors report a case of a giant renal AV fistula successfully treated with staged embolization with use of metallic coils and silk suture. This resulted in a graded reduction in the extreme flow through the fistula, followed by delayed thrombosis and cure of the patient's symptoms.     

Treatment of vertebral arteriovenous fistulas

Twenty patients with vertebral arteriovenous fistulas (eight spontaneous, six traumatic without vertebral artery transection, and six traumatic with vertebral artery transection) were treated by transvascular embolization techniques, resulting in complete fistula closure in all patients. The fistulas were located at C1-C2 in 45%, C2-C3 in 25%, C4-C5 in 15%, C5-C6 in 10%, and C6-C7 in 5%. Trauma was the most common cause: 30% followed knife wounds, 20% followed gunshot injuries, and 10% followed blunt trauma. Eight patients had spontaneous fistulas, two associated with fibromuscular dysplasia. Three patients-all with large, long-standing fistulas-developed neurologic deficits coincident with the abrupt closure of the fistula, which resolved with reestablishment of fistula flow. Two of these patients were treated by staged closure; the other one by gradual closure. In all three cases the result was complete fistula closure without neurologic sequelae. The remaining spontaneous fistulas were all closed by balloon embolization with preservation of the vertebral artery and without deficits. The six patients with traumatic fistulas without transection were cured by balloon embolization, without deficits; in four there was also preservation of vertebral flow. The other six patients had traumatic fistulas with transection and were all cured by balloon embolization with preservation of flow in two. Four patients required bilateral approaches to the fistula to achieve complete fistula closure. The only complication was a mild residual Wallenberg syndrome after occlusion of the posterior inferior cerebellar artery in the treatment of a transection located at C1. In our opinion, transvascular techniques are the treatment of choice for vertebral arteriovenous fistulas.     

Transarterial platinum coil embolization of carotid-cavernous fistulas

Of the 227 embolization procedures performed by our neurointerventional section for symptomatic carotid-cavernous fistulas over the past 10 years, five involved placement of platinum coils in the cavernous sinus from a transarterial route. In four patients, prior transarterial balloon procedures had failed to produce fistula closure. In the fifth patient, with Ehlers-Danlos syndrome, a prior transvenous embolization attempt was unsuccessful. In three patients, complete closure of the carotid-cavernous fistula was achieved with preservation of the parent artery. In one patient, the earliest treated, a portion of a platinum coil projected through the fistula into the parent artery. To eliminate the risk of clot formation and distal embolization, internal carotid occlusion was performed and tolerated without deficits. In the last patient, closure of the anterior drainage was achieved, but complicated by distal migration of the platinum coils with transient aggravation of ocular symptoms. Attempts to occlude the remaining cortical drainage were unsuccessful with platinum coils; therefore, a balloon was used to obliterate the small remaining fistula. Transarterial platinum coil embolization is an alternative treatment for symptomatic carotid-cavernous fistulas that cannot be closed successfully by other embolization techniques. The development of shorter, more thrombogenic, detachable or retrievable coils may make this technique more promising in the future.     

Transarterial treatment of direct carotico-cavernous fistulas with coils and Onyx

Introduction

The purpose of this study was to evaluate the role of combination of liquid embolic agent ethylene vinyl alcohol copolymer (Onyx) and detachable coils in the treatment of direct carotico-cavernous fistulas (CCFs).

Methods

We prospectively collected clinical and radiological data of all patients who underwent embolization of direct CCFs at our institution over a period of 21 months. The clinical parameters, angioarchitecture, presence of cortical venous reflux, volume of Onyx used, number of coils used, extent of embolization and complications were recorded.

Results

A total of 21 consecutive patients (18 men and 3 women, 14 to 48 years) with direct CCF underwent embolization with a combination of coils and Onyx. Embolization was done through the arterial route in all cases. Complete obliteration of the fistula was achieved in 19 of 21 cases. Cast embolization in middle cerebral artery occurred in one patient; however, the cast was completely retrieved with Solitaire device, and the patient did not have any neurological deficit. All completely treated patients reported relief of symptoms at varying intervals. At 6-month follow-up, none of the patients with complete occlusion of the fistula showed any recurrence.

Conclusion

The adjuvant use of Onyx with detachable coils in direct CCF through the arterial route is a safe and effective method for embolization with immediate and complete occlusion of the fistula. To the best of our knowledge, this is the first case series of demonstration of arterial use of Onyx with coils in the treatment of direct CCFs.     

Dural arteriovenous fistulas involving the inferior petrosal sinus: angiographic findings in six patients

We report the angiographic findings from six patients with intracranial dural arteriovenous fistulas of the inferior petrosal sinus and describe the clinical presentation, vascular anatomy, and embolization techniques used in the treatment of this disorder. Dural arteriovenous fistulas at this site are rare; of 105 patients diagnosed with this abnormality, only six had lesions involving the inferior petrosal sinus. The patients included three men and three women, ranging in age from 41 to 75 years. Patients presented with bruit, proptosis, abducens palsy, or loss of vision, and symptoms were present for up to 1 year prior to diagnosis. These presentations were similar to cavernous sinus arteriovenous fistulas. The arterial supply in all cases was from branches of the external carotid artery and in three cases from the meningohypophyseal trunk of the internal carotid artery. Venous drainage in four patients was via the cavernous sinus to the superior ophthalmic vein. The remaining two patients had drainage primarily to the jugular bulb. In four patients treatment was performed by introducing wire coils into the fistula from the transvenous route. This approach could be used even though the inferior petrosal sinus was thrombosed. One patient, treated early in the series, had only transarterial embolization with both liquid adhesives and particulate embolic agents. One patient had an asymptomatic fistula that was not treated. All patients were cured, as evidenced both angiographically and clinically during the follow-up period. Three patients experienced complications from angiography and treatment: two had transverse sinus thrombosis and one had a transient ischemic attack.     

Use of a balloon and N-butyl-2-cyanoacrylate for treatment of arteriovenous fistula

We report a patient who developed a large arteriovenous fistula in right lower extremity after gunshot injury. Because other endovascular methods failed, the patient was successfully treated with concomitant use of detachable latex balloon and N-butyl-2-cyanoacrylate (NBCA). The combination of detachable balloon and NBCA can be effectively used for endovascular treatment of peripheral arteriovenous fistulas in selected cases when effective embolization could not be achieved with other embolizing agents or their various combinations.     

Pulmonary arteriovenous malformations: effect of embolization on right-to-left shunt,hypoxemia, and exercise tolerance in 66 patients

OBJECTIVE: This study assessed the effect and safety of percutaneous transcatheter coil embolization of pulmonary arteriovenous malformations. MATERIALS AND METHODS: In 58 (88%) of 66 patients, all malformations with feeding vessels greater than or equal to 3 mm in diameter were embolized with steel coils. Arterial oxygen saturation at rest and exercise, intrapulmonary right-to-left anatomic shunt fraction ((99m)Tc-macroaggregate injection), maximum exercise capacity (incremental work rate test), and pulmonary function were measured before and after embolization. Complications were analyzed. RESULTS: Three categories of patients were identified. Patients in group 1 (27%) had complete occlusion of all angiographically visible pulmonary arteriovenous malformations; patients in group 2 (61%) had complete occlusion of all malformations with feeding vessels greater than or equal to 3 mm in diameter, but with smaller lesions persisting; and patients in group 3 (12%) had incomplete embolization, with feeding vessels greater than or equal to 3 mm in diameter remaining. The mean right-to-left shunt after embolization was least in group 1 (7%), intermediate in group 2 (10%), and greatest in group 3 (19%). Arterial oxygen saturation and right-to-left shunt fraction returned to normal levels (>96% and <3.5%, respectively) in 33% of patients. A significant improvement occurred after embolization in carbon monoxide diffusing capacity per unit of alveolar volume and in exercise capacity in 16 and 10 patients, respectively. In 93 procedures, 12 complications (13%) occurred. CONCLUSION: Coil embolization of pulmonary arteriovenous malformations is effective in reducing right-to-left anatomic shunt fraction and in improving arterial oxygenation. Coil embolization of pulmonary arteriovenous malformations is well tolerated and has a low complication rate.