Congenital arteriovenous communications. A report on three cases of systemic extravisceral fistulae (author's transl)]

Arteriovenous fistulae are rarely seen in children and are usually the result of malformations. Three cases are reported which were unusual because of their location and the manner in which they evolved. A simplified classification of these lesions is described and 582 cases from the published literature are reviewed.     

Therapeutic embolization of facial arteriovenous fistulae.

Two cases of percutaneous transfemoral embolization of facial hemangiomas and arteriovenous (AV) malformations are reported. In both cases, Ivalon shavings were injected through a percutaneously placed catheter to permanently occlude peripheral feeders of the AV malformation. In one case, because of the size of the large venous sacs associated with the malformation, a steel coil was introduced to form a baffle, over which several additional strands of surgical silk were introduced to obliterate these sacs. These cases emphasize the need for embolization of small feeding arteries to prevent recurrence by collateral channels. To achieve this, specific-sized emboli are necessary; Ivalon is a suitable embolic material.     

Phase-contrast MR angiography of intracranial dural arteriovenous fistulae

MRI and phase-contrast MR angiography (PC MRA) were obtained in 13 patients with angiographically confirmed intracranial dural arteriovenous fistulae (DAVF). Three- and two-dimensional PC MRA was obtained with low (6–20 cm/s) and high (> 40 cm/s) velocity encoding along the three main body axes. MRI showed focal or diffuse signal abnormalities in the brain parenchyma in six patients, dilated cortical veins in seven, venous pouches in four with type IV DAVF and enlargement of the superior ophthalmic vein in three patients with DAVF of the cavernous sinus. However, it showed none of the fistula sites and did not allow reliable identification of feeding arteries. 3D PC MRA enabled identification of the fistula and enlarged feeding arteries in six cases each. Stenosis or occlusion of the dural sinuses was detected in six of eight cases on 3D PC MRA with low velocity encoding. In six patients with type II DAVF phase reconstruction of 2D PC MRA demonstrated flow reversal in the dural sinuses or superior ophthalmic vein. Received: 14 May 1998 Accepted: 15 December 1998     

Embolisation of spinal dural arteriovenous fistulae with Onyx

Surgery is currently the standard treatment for spinal dural arteriovenous fistulae (DAVF). Endovascular embolisation of these lesions using N-butyl cyanoacrylate (NBCA) has a high success rate. Onyx is a new liquid embolic agent whose viscosity makes it suitable for treatment of spinal DAVF where penetration into the proximal radicular vein is required. It is delivered with greater control than NBCA without the necessity for rapid withdrawal of the catheter and may therefore overcome some of the drawbacks of NBCA. We report two patients who underwent Onyx embolisation of spinal DAVF; to our knowledge this is the first such report.     

Doppler echo in evaluating arteriovenous fistulae for dialysis

US-Doppler has recently gained attention as a noninvasive method for the functional evaluation of arteriovenous fistulas (FAV). Twenty patients with well-functioning FAV were studied, and the results compared with those from a control group of 10 healthy subjects. Time average velocity (TAV) was calculated as hemodialysis parameter, together with telesystolic (Vts) and telediastolic (Vtd) velocities, absolute (F) and normalized (FN) fluxes to the area unit (cm2 1) and resistance index (IR). All of them proved to be statistically significant indexes of FAV functionality. Doppler has thus proved to be a valuable means both to calculate FAV capacity in a patient and to establish FAV functionality. Four parameters are recommended: FN greater than 2000 ml/min/cm2; IR less than 0.05; TAV greater than 50 cm/s: and Vtd greater than 35 cm/s.     

Chronic traumatic arteriovenous fistulae (author's transl)]

In two patients with femoral arterio-venous fistulae angiography could show arterial and venous collaterals with differing circulation phases. When angiography shows retrograde flow in the artery distal to the fistula, the volume of arterial collateral circulation is unrelated to the peripheral blood-supply. Venous collateral circulation has to be included in the fistular circulation. Angiography permits distinguishing a venous by-pass circulation for the return of blood from the periphery. In one patient a large aneurysm of the iliac vein was found. Special features of angiography, particularly after surgical closure of the fistula, are mentioned.     

血管内栓塞治疗硬脊膜动静脉瘘临床结果

目的：报道血管内栓塞治疗硬脊膜动静脉瘘(SDAVF)的临床和影像学结果。方法回顾性分析青岛大学附属医院介入医学科治疗的7例SDAVF患者流行病学、脊髓MRI及脊髓DSA、治疗方法及术后随访资料。结果7例患者脊髓MRI均有异常发现,DSA明确诊断后均行血管内栓塞治疗。术后随访6个月,7例患者症状得到不同程度改善,其中经NBCA胶栓塞治疗4例无复发,经Onyx胶栓塞治疗3例中1例复发。结论血管内栓塞是治疗SDAVF有效、安全的方法,但还需进一步探索。     

N-butyl 2-cyanoacrylate embolization of spinal dural arteriovenous fistulae

BACKGROUND AND PURPOSE: Because they are not well established, we investigated the technical success and recurrence rates of n-butyl 2-cyanoacrylate (NBCA) embolization of spinal dural arteriovenous fistulae (SDAVF), and assessed clinical outcomes. METHODS: We retrospectively studied all patients with SDAVF treated by NBCA embolization at our institution over an 8-year period. Gait and micturition disabilities were analyzed. Follow-up periods averaged 3.1 years (range, 1 month to 8.9 years). RESULTS: NBCA embolization was feasible in 74% (20/27) of patients. Of 20 patients who underwent embolization, initial embolization failure occurred in two (10%) and fistula occurrence in three (15%). All five patients in whom NBCA embolization failed underwent surgery. All patients who underwent embolization had either improved (55%) or unchanged (45%) gait disability at last follow-up. Seventeen (85%) patients had improved (40%) or unchanged (45%) micturition disability, but three (15%) had worsened. Mean Aminoff gait disability grade significantly decreased at last follow-up (2.4 [1.4] average [SD] vs 3.2 [1.4] [P = .0008]). Mean micturition disability grade decreased, but not significantly (1.4 [1.0] vs 1.7 [1.1] [P = .28]). CONCLUSION: NBCA embolization of SDAVF was technically feasible in 75% of patients. Initial apparent successful embolization was achieved in 90%; the fistula recurrence rate (failure to occlude the draining vein) for NBCA was 15%. Comparing favorably to surgical series, NBCA embolization of SDAVF appears efficacious, significantly improving mean gait disability by almost one grade at last follow-up. Close clinical and angiographic surveillance is mandatory. Longer and more uniform follow-up is needed to determine if clinical improvement and stabilization after NBCA embolization are sustained.     

Endovascular therapy of arteriovenous fistulae with electrolytically detachable coils

We report our experience in using Guglielmi electrolytically detachable coils (GDC) alone or in combination with other materials in the treatment of intracranial or cervical high-flow fistulae. We treated 14 patients with arteriovenous fistulae on brain-supplying vessels – three involving the external carotid or the vertebral artery, five the cavernous sinus and six the dural sinuses – by endovascular occlusion using electrolytically detachable platinum coils. The fistula was caused by trauma in six cases. In one case Ehlers-Danlos syndrome was the underlying disease, and in the remaining seven cases no aetiology could be found. Fistulae of the external carotid and vertebral arteries and caroticocavernous fistulae were reached via the transarterial route, while in all dural fistulae a combined transarterial-transvenous approach was chosen. All fistulae were treated using electrolytically detachable coils. While small fistulae could be occluded with electrolytically detachable coils alone, large fistulae were treated by using coils to build a stable basket for other types of coil or balloons. In 11 of the 14 patients, endovascular treatment resulted in complete occlusion of the fistula; in the remaining three occlusion was subtotal. Symptoms and signs were completely abolished by this treatment in 12 patients and reduced in 2. On clinical and neuroradiological follow-up (mean 16 months) no reappearance of symptoms was recorded. Received: 17 March 1999 Accepted: 27 April 1999     

Congenital arteriovenous malformations: tailored embolotherapy

Congenital arteriovenous malformations (AVMs) involving the pelvis or an extremity were occluded in 16 symptomatic patients, who subsequently underwent tailored embolotherapy. An additional 11 patients did not undergo embolization due to unfavorable vascular anatomy or lack of significant symptoms. Permanent occlusive agents including isobutyl cyanoacrylate, particles of polyvinyl alcohol foam, and coils were used to embolize the multiple feeding vessels and, when possible, the nidus of the AVM. All patients experienced dramatic reduction in pain and resolution of ulceration and bleeding, with a mean follow-up period of 41 months. Symptoms recurred in four patients but again resolved with repeat embolization. The authors conclude that selective and repetitive embolization is highly effective in palliation of symptomatic congenital AVMs.     

Determination of blood flow through arteriovenous fistulae and shunts.

A videodensitometric method for estimating relative flow was employed in a patient with a bovine arteriovenous fistula. Analogous arteriovenous communications of different sizes were created in two dogs for comparison. Local and general hemodynamic parameters were measured. The videodensitometric method proved to be highly accurate compared to electromagnetic flow readings and is the method of choice in estimating shunt flow in connection with routine angiography.