Roentgen findings in aorto-enteric fistulae.

Six cases of aorto-enteric fistulas are discussed. In three patients the aorta ruptured into the duodenum and in three there was rupture into the esophagus. Aorto-enteric fistula is usually caused by atherosclerosis, but may also be due to syphilis or tuberculosis. Following insertion of an aortic graft, fistula is usually the result of breakdown of the anastomosis. Gastrointestinal bleeding usually heralds the problem. The roentgen signs of rupture are pressure on the esophagus or intestine, bleeding into the wall or lumen, and demonstration of the fistula. The abnormal connection may not be demonstrable by aortography. These signs permit early diagnosis and subsequent possible life saving surgical correction.     

Aorto-enteric fistulae: the role of radiology

Four patients with aorto-enteric fistulae are reported and a fifth case of jejunal ulceration is included, which is thought to be the early state of fistula formation. The clinical presentation and radiological investigation of these patients is described and discussed. The most important presenting symptom is of bleeding from the upper gastrointestinal tract. Analysis of the pre-operative investigations showed that barium studies were diagnostic in each of the cases. The important role of the radiologist, in making the diagnosis of an aortoenteric fistula in patients who have had aortic reconstructive surgery, is emphasised.     

Computed tomography vs barium studies in the acutely symptomatic patient with Crohn disease

Gastrointestinal contrast studies and CT performed on 43 patients with known Crohn disease with acute symptoms were retrospectively reviewed to assess the ability of each study to define the location and extent of disease. In 39 of 43 (91%) patients the contrast studies and CT agreed on the location of active disease. However, in 15 of 43 (35%) patients, contrast studies demonstrated additional areas of mucosal disease remote from the major area of activity that were not suggested by CT. In addition to demonstrating more extensive mucosal disease, contrast studies proved superior in demonstrating enteroenteric fistulae, sinus tracts, strictures, postsurgical anatomy, and relation of recurrence to anastomosis. Computed tomography proved superior in demonstrating mesenteric inflammation, abscesses, enterovesical and enterocutaneous fistulae, fistula to iliopsoas muscle and to sacrum. We conclude that in the patient with suspected abscess, enterovesical or enterocutaneous fistula, CT is the study of choice. In other clinical circumstances both CT and contrast studies should be performed since they are complementary.     

Endovascular repair of an aortopulmonary artery fistula with use of controlled-release coils

Aortopulmonary artery fistula is traditionally treated surgically. The present case report describes endovascular repair of an aortopulmonary artery fistula in a patient in whom two thoracotomies had been performed. The fistula occurred at the site of a pseudoaneurysm from the proximal anastomosis of a graft placed to treat a type B aortic dissection. Two controlled-release endovascular coils were positioned across the fistula, resulting in immediate closure. The fistula remains closed with resolution of the pseudoaneurysm after more than 3 years of follow-up.     

Temporary endovascular control of a bleeding aortoenteric fistula by transcatheter coil embolization

A 67-year-old man presented with gastrointestinal bleeding resulting from a fistula between the aortic stump and the fourth part of the duodenum 14 months after an axillobifemoral bypass, graft excision, and aortic stump closure for aortic graft infection. The patient initially refused any attempt at definitive surgical treatment so coil embolization of the aortic stump was performed via a brachial approach. Coil embolization may be a useful adjunct in the management of such difficult problems. This approach may buy time and allow careful planning of a definitive treatment or may serve as a palliative procedure in inoperable patients.     

CT findings of secondary aorto-enteric fistulae

PURPOSE: The aim of our study was to review CT findings concerning secondary aorto-enteric fistulae (AEF). In particular, we aimed to evaluate signs of contrast medium extravasation from the aortic graft into the bowel (active bleeding), in correlation with clinical and surgical reports. MATERIALS AND METHODS: Clinical and CT findings were retrospectively evaluated in 13 surgically proven cases of AEF. All patients underwent spiral CT examination with biphasic contrast technique, before and 30 and 80 seconds after intravenous injection of 120-150 ml of contrast medium (Ultravist 370; flow rate 2.5-3 ml/sec). Late scans (240 seconds) were also acquired on surgical anastomoses. We used 3 mm (arterial phase) and 5 mm (venous phase) slices. RESULTS: At surgery, all 13 patients presented a communication between the bowel and the aortic graft. At CT examination, all 13 patients presented one or more CT signs indicating AEF (perigraft soft tissue, perigraft fluid, ectopic air or bowel wall thickening). Moreover, in 6 out of 13 patients, contrast medium extravasation from the aortic graft into the small bowel (active bleeding) was detected with CT. Detection of active bleeding was possible because CT examinations were performed without oral administration of contrast medium. CONCLUSIONS: CT is easily and readily available and provides an accurate evaluation of the aorta and surrounding retroperitoneal tissues. In our study we were able to identify the CT sign of active bleeding in more than a half of the patients with acute gastrointestinal bleeding (66%). Hence, we suggest that patients undergo CT examination without oral contrast medium administration in order to better appreciate the presence of active bleeding.     

Gastrointestinal complications of aortic bypass surgery.

Gastrointestinal bleeding following abdominal aortic bypass surgery is not uncommon, as approximately 20% of patients with abdominal aortic aneurysms have peptic ulcer disease. We have recently seen three patients who presented with gastrointestinal bleeding secondary to the complications of their surgery. The cause of the bleeding was aortoduodenal fistula, graft erosion into the sigmoid colon and ischaemic colitis respectively. The correct diagnosis was only considered in one patient, although in retrospect it should have been suggested in all three. Our experiences with these complications and their clinical and radiological presentation form the basis for this paper.     

Secondary aortoenteric fistula: active bleeding detected with multi-detector-row CT

We report a case of active bleeding of a secondary aortoenteric fistula (SAEF), in which CT angiography with multi-detector-row CT (MDCT) was finally diagnostic after negative catheter angiography and unsatisfactory endoscopy. The MDCT angiography clearly demonstrated the fistulous tract between the abdominal aortic graft and the duodenum. The dynamic process of bleeding was confirmed as a net increase of contrast agent accumulation in the duodenum through different phases. The MDCT angiography with its excellent 3D image quality is therefore a valuable method in the assessment of active SAEF bleeding.     

The red connection: a review of aortic and arterial fistulae with an emphasis on CT findings

Fistulae between the aorta and adjacent structures are a rare, emergent, and potentially life-threatening process. Most commonly, aortic fistulae arise secondarily as a complication of prior aortic surgery with fistulization to adjacent structures. Rarely, a primary fistula may arise from the aorta in the setting of a pre-existing aneurysm or from a mass, inflammation, or infection. Although the incidence of aortic fistulae remains low, the frequency continues to increase as aortic surgical interventions and post-surgical follow-up with imaging become more common. Computed tomography (CT) is the modality of choice in evaluating the patient with suspected aortic fistula because of its accessibility and short scan time. In addition, CT allows for more clear depiction of para-aortic or intra-aortic gas than ultrasound or magnetic resonance (MR). This gas may be the first clue of a fistula. Given the high mortality associated with aortic fistulae, familiarity with the imaging findings of the spectrum of aortic fistulae is essential knowledge in the emergency setting. This review will discuss the imaging appearance of aortic and arterial fistulae to the bronchi, esophagus, gastrointestinal tract, ureters, and veins on CT.     

An unusual presentation of thoracic aortic aneurysm rupturing into the esophagus: an autopsy case report

Ruptured aortic aneurysms often present with sudden death, and have varied signs and symptoms depending on the site of rupture and hemorrhage. We report a case of an aortic aneurysm with an aorto-esophageal fistula, which showed slow gastrointestinal bleeding for days before death. A 79-year-old male was brought to a hospital emergency unit, with a history of melena for about 3 days, and recent hematemesis. He collapsed immediately after endoscopy and died. A forensic autopsy which was performed due to possible medical malpractice demonstrated a large saccular aneurysm of the descending thoracic aorta with a fistula into the esophagus. A significant finding was a lid or valve shaped thrombus covering the aortic orifice of the fistula, which may have partly contributed to slow bleeding, and which may have been dislodged by endoscopy. This case suggests that very careful management of aorto-esophageal fistula is needed in patients with clinical signs of possible thoracic aortic aneurysm with slow hemorrhage.     

Adjuvant use of e-aminocaproic acid (Amicar) in the endovascular treatment of cranial arteriovenous fistulae

We report our experience with the use of the antifibrinolytic agent ɛ -aminocaproic acid (EACA), Amicar, as an adjuvant to endovascular treatment of cranial arteriovenous fistulae. We also review applications of antifibrinolytic agents to neurovascular disorders and discuss the mechanism of action, dosing strategy, contraindications, and possible complications associated with the use of EACA. We identified 13 patients with cranial arteriovenous fistulae (five direct carotid cavernous fistulae [CCF], seven dural arteriovenous fistulae [DAVF], and one vein of Galen malformation) who received EACA as an adjunct to endovascular treatment. In all cases embolic coils were the primary embolic agent. We reviewed the modes of initial endovascular therapy and angiographic findings immediately thereafter and the response to EACA. Two direct CCF and two DAVF were completely thrombosed on follow-up angiography, and two DAVF demonstrated diminished flow after EACA therapy. Seven fistulae did not respond to EACA. Four of eight tightly coiled fistulae thrombosed, while none of five loosely coiled fistulae thrombosed. None of four cases with a residual fistula separate from the coil mass underwent thrombosis with EACA, while four of nine cases without a separate fistula thrombosed. There was no morbidity related to EACA therapy. EACA may thus be useful as an adjunct to endovascular treatment of cranial arteriovenous fistulae. Loose or incomplete coil packing of the fistula predicts a poor response to EACA therapy. Received: 18 March 1999 Accepted: 11 August 1999     

医源性肠外瘘的分型和CT表现

目的:探讨医源性肠外瘘的分型和CT表现.方法:对754例医源性肠外瘘实施了CT检查.参照临床分型,将肠外瘘分为管状瘘、唇状瘘和断端瘘三个类型,并分析其CT征象.结果:管状瘘所占比例最高(占68.70%),表现为内、外口之间不均匀的管道形成;唇状瘘(占31.30%)的CT征象特点是较大的外口,呈唇状改变,无瘘管形成.管状瘘的腹腔和腹膜后脓肿发生率明显高于唇状瘘(P＜0.01),而唇状瘘的肠壁炎性改变发生率较高(P＜0.01).结论:CT检查能够显示医源性肠外瘘的临床分型,对治疗具有指导性作用.     

创伤性动脉瘤和动静脉瘘

目的：为了进一步探讨创伤性动脉瘤和动静脉瘘的手术方法，我院血管外科分析了１９６３年６月～１９９５年１２月，经手术治疗的创伤性动脉瘤和动静脉瘘９６例。其中创伤性动脉瘤５５例，含６３个动脉瘤，动静脉瘘４１例，含４３个动静脉瘘。方法：根据血管造影和手术发现，将创伤性动脉瘤和动静脉瘘各分为四个类型。手术方法包括直接修补、单纯或四头结扎、瘤或瘘切除然后行对端吻合或大隐静脉或人造血管移植。结果：除１例左颈总动脉根部动脉瘤伴左颈总动脉—无名静脉瘘术后１９小时死于弥漫性血管内凝血外，其余无死亡。动脉瘤和动静脉瘘得到随访的分别为７９．６％和７８．０％。远期随访效果较佳。结论：不同类型的创伤性动脉瘤和动静脉瘘，应采用不同的手术方法。     

Venous covered stent: successful occlusion of a symptomatic internal iliac arteriovenous fistula

We report the placement of a covered stent within the internal iliac vein (IIV) to occlude a symptomatic iatrogenic internal iliac arteriovenous fistula following an abdominal aortic graft. Angiography revealed a direct communication between an internal iliac graft to artery anastomosis and the right IIV with rapid shunting into the inferior vena cava and a small associated pseudoaneurysm. Femoral, brachial or axillary arterial access was precluded. The fistula was successfully occluded by a stent-graft placed in the IIV. Arteriovenous fistula can be treated in a number of ways including covered stent placement on the arterial side. To the best of our knowledge this is the first time placement in a vein has been described. Where access is difficult or the procedure carries a high risk of complication, a venous covered stent may offer an alternative.     

Effectiveness of Collateral Vein Embolization for Salvage of Immature Native Arteriovenous Fistulas

PurposeTo investigate the value of collateral vein embolization (CVE) as a salvage treatment for nonmaturing native arteriovenous fistulae (AVFs) in patients requiring hemodialysis.Materials and MethodsA total of 49 patients undergoing CVE (N = 65) for immature native AVFs at a single institution were reviewed. The study included 42 patients treated by 56 embolizations. Average fistula age at time of intervention was 18.2 weeks. Each patient underwent angiographic evaluation for fistula immaturity, with clinical success defined by initiation of single-session hemodialysis through the native fistula.ResultsFistula maturity was achieved in 32 of 42 patients (76.2%). No major complications occurred. Average time from CVE to fistula maturity was 38.4 days. Angioplasty done with CVE was found in a statistically higher percentage of patients with fistula success versus failure (31.3% vs 8.3%; P = .039). Radiocephalic fistulae were seen in a higher percentage of fistula failures compared with successes, but the results were not statistically significant (83.3% vs 59.4%; P = .054). Thirty-four patients underwent CVE without angioplasty, which resulted in successful fistula maturation in 22 cases (64.7%). Radiocephalic fistulae were again seen in a higher percentage of fistula failures compared with successes, but the findings did not meet statistical significance (81.8% vs 54.5%; P = .052).ConclusionsCoil embolization of competing collateral vessels as a salvage treatment for nonfunctioning autologous AVFs is a viable treatment option in the majority of patients. Patients with radiocephalic fistulae may be at higher risk for primary fistula failure, but the present data are inconclusive.     

Imaging features of colovesical fistulae on MRI

Objectives MRI is routinely used in the investigation of colovesical fistulae at our institute. Several papers have alluded to its usefulness in achieving the diagnosis; however, there is a paucity of literature on its imaging findings. Our objective was to quantify the MRI characteristics of these fistulae. Methods We selected all cases over a 4-year period with a final clinical diagnosis of colovesical fistula which had been investigated with MRI. The MRI scans were reviewed in a consensus fashion by two consultant uroradiologists. Their MRI features were quantified. Results There were 40 cases of colovesical fistulae. On MRI, the fistula morphology consistently fell into three patterns. The most common pattern (71%) demonstrated an intervening abscess between the bowel wall and bladder wall. The second pattern (15%) had a visible track between the affected bowel and bladder. The third pattern (13%) was a complete loss of fat plane between the affected bladder and bowel wall. MRI correctly determined the underlying aetiology in 63% of cases. Conclusions MRI is a useful imaging modality in the diagnosis of colovesical fistulae. The fistulae appear to have three characteristic morphological patterns that may aid future diagnoses of colovesical fistulae. To the authors' knowledge, this is the first publication of the MRI findings in colovesical fistulae.     

Image-guided surgery for anal fistula in a 0.5T interventional MRI unit

PURPOSE: To determine whether MR-guided anorectal surgery is feasible, and to develop techniques for MR-guided anal fistula surgery. MATERIALS AND METHODS: Six patients with pilonidal sinus (PNS), and 21 with suspected anal fistulae were operated on in the GE Signa SPIO 0.5T interventional MRI unit. Procedures were performed with magnet-safe Lockhart-Mummery fistula probes. Preprocedural and intra-operative MRI (IOMRI) techniques were used to identify the extent of the fistula tracts and septic foci, and to ensure the adequacy of the surgical procedure. RESULTS: IOMRI demonstrated the PNS lesions and the adequacy of excision. Imaging failed to demonstrate a fistula in two patients, as confirmed by surgical examination. No images were obtained in one patient due to his size (weight in excess of 100 kg). In 18 patients a fistula tract or abscess was demonstrated and IOMRI was used to assess the adequacy of the surgical procedure. In three patients this demonstrated incomplete drainage of septic foci, which was not obvious on inspection of the surgical field. We believe that in these patients IOMRI prevented an incomplete procedure and the potential requirement for a second operation. Further surgery was performed to rectify this situation. The fistula tract was laid open in 13 patients, and a Seton drain was inserted in five. CONCLUSION: MRI-guided surgery for anal fistula is feasible. IOMRI demonstrates the exact anatomy of the tracts and abscesses, and confirms that all have been adequately treated. We believe it may become particularly useful in surgery for recurrent and complex anal fistulae, and may lead to fewer recurrences.     

Detection of prosthetic vascular complications: comparison of CT and angiography

The value of CT and angiography to detect complications of prosthetic arterial grafting was compared in 24 patients. There was a total of 27 grafts including 18 aortic or aortofemoral, five femoral-popliteal, two femoral-femoral, and two axillary-femoral reconstructions. Nineteen grafts were uninfected; eight were infected. In the absence of infection, the complications and the percentages detected by the two procedures were as follows: five graft occlusions (CT 80%, angiography 100%), six pseudoaneurysms (CT 100%, angiography 83%), three with perigraft fluid (CT 100%, angiography 0%), and one with pseudointimal hyperplasia (CT 100%, angiography 0%). Seven grafts were normal and without abnormalities on both CT and angiography. In the presence of infection the results were as follows: eight with perigraft fluid (CT 100%, angiography 0%), four with perigraft or intragraft gas (CT 100%, angiography 0%), three pseudoaneurysms (CT 100%, angiography 100%), two open groin wounds (CT 100%, angiography 0%), and two graft occlusions (CT 100%, angiography 100%). In addition, three patients with infected grafts had graft enteric fistulae. All three had fluid around the proximal anastomosis and two had gas around the graft as well. The data show that angiography is sufficient for patients with graft occlusion if there is no suspicion of infection, postoperative hemorrhage, or anastomotic pseudoaneurysm. In these cases CT has an ancillary role in detecting hemorrhage and defining pseudoaneurysms. CT is superior to angiography in patients with graft infection.     

Thermal Resistance Anastomosis Device for the Percutaneous Creation of Arteriovenous Fistulae for Hemodialysis

Purpose

To evaluate the safety and efficacy of arteriovenous fistula (AVF) creation with a thermal resistance anastomosis device (TRAD).

Case report: MRI evaluation of congenital coronary artery fistulae

Congenital coronary artery fistula is a rare disease and MRI is a promising technique that may be useful to demonstrate the coronary artery tree. We report three patients who underwent cardiac MRI to investigate right coronary artery fistulae. On clinical examination, a continuous murmur was heard along the left sternal border, and chest X-ray showed moderate cardiomegaly with enlargement of right chambers in all patients. Transthoracic Doppler echocardiography showed fistulae in two cases; the third case was not demonstrated by transthoracic or transoesophageal echocardiography. MRI demonstrated the course of the fistulous vessels in all patients. All patients underwent surgical closure of their coronary artery fistulae. MRI may show detailed anatomy of congenital coronary artery fistulae and may be useful as an additional non-invasive method in their investigation.