Diagnosis and treatment of pulmonary arteriovenous fistulas

Pulmonary arteriovenous fistulas are rare malformations often associated with Rendu-Osler-Weber (ROW) disease. Morbidity and mortality are significant and arise from hemorrhagic and neurological complications.We report the cases of two patients, mother and son, with earlier diagnoses of ROW disease, who suffered, respectively, a stroke and a brain abscess with massive pulmonary thromboembolism. Helicoid computed axial tomographic scans demonstrated pulmonary arteriovenous fistulas in both. Given these findings, we performed embolotherapy.     

Diagnosis and therapy of arteriovenous lung fistulas]

On the basis of 6 own cases, 5 of which were observed during one year, the clinical picture, the diagnostics and the therapy of the arteriovenous pulmonary fistula are described. Of decisive diagnostic importance is the angiography of the pulmonary artery which should always be used for the clarification of unclear pulmonary foci as well as clinically unclear cyanosis. For the removal of this shunt connection in the lesser circulatory system therapeutically only the operation comes into question. On account of the threatening complications and the inclination to the dilation of the fistula with growing age it is indicated also in cases with only slight haemodynamic effect. Dependent on the anatomical position of the fistula the ligature of the afferent artery is recommended.     

Duplex ultrasound determination of shunt volume in iatrogenic arteriovenous fistulas after heart catheterization

AIM: To determine the shunt volume of iatrogenic arteriovenous fistula (AVF) following arterial puncture of the groin and to evaluate its impact on natural history and clinical outcome. METHOD: Over a period of 12 months, 22 patients (p) with a newly acquired AVF were followed up. The arteriovenous shunt volume was determined by means of colored duplex- and doppler sonography immediately after diagnosis of AVF. RESULTS: Spontaneous closure of AVF was seen in 10 p (46%) during follow-up examination, whereas 12 p (54%) showed a persistence of their AVF. The median (I50) shunt volume of closed AVF was 310 (250-350) ml/min and 350 (160-510) ml/min for persistent fistulae (p = ns). A shunt volume of > or = 400 ml/min was determined as a significant (p < or = 0.05) cut-off point for prolonged persistence of AVF. CONCLUSION: Because spontaneous closure of AVF was 46% in the course of the first year, conservative management with regular duplex control seems to be justified at least for this duration. Patients with a shunt volume of > or = 400 ml/min have an increased risk of prolonged AVF persistence and therefore should be included in long-term follow-up with special attention to development of hemodynamic relevance.     

硬脑膜动静脉瘘的全面认识与正确治疗

随着介入神经放射学的发展，对硬脑膜动静脉瘘（DAVF）的认识不断深入，临床上对DAVF的正确诊断率越来越高。近几年来，学者们对该病的影像学表现和血管构筑有了较深入的认识。随着介入栓塞材料的发展，介入栓塞的治愈率明显提高，其他治疗方法也取得了良好疗效。但对该病的真正病因、发病机制和瘘口位置的认识尚不充分，目前所采用的分类方法尚不完善，治疗原则和治疗方式的选择仍不统一，需要脑血管疾病研究者予以足够的重视。     

Incidence and clinical outcome of iatrogenic femoral arteriovenous fistulas: implications for risk stratification and treatment

OBJECTIVES: We sought to determine the incidence of arteriovenous fistulas (AVF), identify risk factors for AVF, and follow up the clinical outcome of femoral AVF. BACKGROUND: Arteriovenous fistulas are a potential harmful complication of cardiac catheterization. Incidence and clinical outcome of iatrogenic AVF are unknown so far, although important for risk stratification and treatment. METHODS: A total of 10,271 consecutive patients undergoing cardiac catheterization were followed up prospectively over a period of three years. Diagnosis of AVF was performed by duplex sonography. RESULTS: The incidence of AVF was 0.86% (n = 88). The following significant and independent risk factors for AVF were identified: high heparin dosage (odds ratio [OR]) = 2.88), coumadin therapy (OR = 2.34), puncture of the left groin (OR = 2.21), arterial hypertension (OR = 1.86), and female gender (OR = 1.84). Within 12 months 38% of all AVF closed spontaneously. No signs of cardiac volume overload or limb damage were observed in patients with persisting AVF. None of the risk factors for AVF influenced the incidence or the rate of AVF closure. Only intensified anticoagulation showed a tendency to extend AVF persistence. CONCLUSIONS: Almost 1% of patients undergoing cardiac catheterization acquire femoral AVF, for which patient- and procedure-related risk factors could be identified. One-third of iatrogenic AVF close spontaneously within one year. Cardiac volume overload and limb damage are highly unlikely with AVF persistence. Thus, a conservative management for at least one year seems to be justified.     

Diagnosis and surgical management of recurrent tracheoesophageal fistulas

Recurrent tracheoesophageal fistula (TEF) is difficult to diagnose and even more difficult to repair. The key to the diagnosis is an adequate contrast study and bronchoscopy. The key to the repair is complete separation of the esophagus from the trachea, with the placement of viable tissue between the two suture lines. I have presented a personal experience with 38 consecutive repairs of recurrent TEFs. The original series of 26 patients had three recurrences, all of which were re‐repaired successfully. My more recent experience with the last 12 patients, who were far more complex, was also successful in ultimately repairing the recurrent TEFs.     

Angiographic management of massive hemobilia due to iatrogenic trauma

Ten patients with massive hemobilia in shock or preshock status were treated with angiography. The hemobilia had been induced by iatrogenic trauma: biliary drainage in seven patients, and surgery, liver biopsy, and angiography in one patient each. Angiography was performed on all patients. Embolization was performed in nine, and in the one remaining patient, spasm of the right anterior hepatic artery and catheter manipulation injured the intima and obliterated the artery. In seven patients with hepatic artery pseudoaneurysm, gelfoam particles were injected in five, however, extravasation could not be prevented in four of these patients. Permanent embolic materials were added and complete hemostatis was obtained. Hemobilia never recurred in any patient. Emergency embolization should be considered as the initial treatment of choice for hemobilia and when pseudoaneurysms are discovered, they should be obliterated by permanent embolic materials. Moreover, tumor thrombus in the portal vein is not a contraindication for this procedure.     

肺动静脉瘘的诊断与治疗

目的归纳肺动静脉瘘（ＰＡＶＦ）的发病原因、临床表现特征及合并症，分析各种诊断方法的优缺点，以提高对ＰＡＶＦ的认识，从而提高诊断水平和治疗效果。方法回顾分析２２例临床病例，结合文献资料总结经验、教训，提高认识。结果２２例中１２例行肺部手术，其中９例术后症状完全消失；１例多发ＰＡＶＦ行左下肺动脉结扎，术后症状明显改善；另１例行左全肺切除，术后早期症状改善，半年后失访。１例弥漫性ＰＡＶＦ行全肺切除，术后１年死亡；另外１０例弥漫性ＰＡＶＦ中５例行非肺部手术，患者能够耐受手术，但ＰＡＶＦ症状改善不明显；５例未行任何特殊治疗，失访。结论超声心动声学造影是确定ＰＡＶＦ的最简单、有效、创伤小的检查方法；肺动脉造影可确定ＰＡＶＦ部位、大小及范围；手术治疗效果肯定，但必须恰当选择适应证。     

软脑膜动静脉瘘的研究进展

软脑膜动静脉瘘在临床上较为罕见,是一种不同于颅内动静脉畸形的血管病变,需要积极干预治疗,然而目前我们对该类病变的认识仍有限。该疾病在国内外研究报道中多为个案,综述及大宗病例报道相对较少。作者通过对相关文献进行综述并结合单中心的临床经验进行总结,从发病机制、自然史、血管构筑、临床表现、治疗方式和并发症等各方面进行阐述,以提高对该类疾病的深层认识。     

Diagnosis and management of acute traumatic arteriovenous fistula

Acute arterial injuries are often complicated by the development of an arteriovenous fistula (AVF). In the acute setting, an AVF may present at the same time as the arterial injury. A case of traumatic AVF in the thigh that presented with normal neurovascular examination findings is reported. AVF was diagnosed by duplex scan and managed promptly. The authors suggest that duplex imaging together with arteriography, where appropriate, should be performed routinely when penetrating wounds are in close proximity to major vessels despite a normal clinical neurovascular examination.     

Prevention of thrombosis in arteriovenous fistulas

To prevent thrombosis in arteriovenous fistulas it is necessary to obtain the knowledgeable cooperation not only of the whole health care team, but also of the patient. The first step is preservation of forearm veins by avoiding unnecessary venipunctures in patients with chronic renal failure. Fistulas should be constructed well in advance of need and use natural rather than prosthetic veins whenever possible. Major surgery elsewhere is a potential cause of fistula thrombosis. Fistula construction is often best delayed till major surgery is over and until the veins have recovered from the effects of systemic steroid therapy. Avoidance of premature fistula cannulation and correct needling techniques help to prevent vein wall damage. Alertness to the presence of high venous pressures on dialysis and observation of inefficient dialysis due to recirculation should lead to detection of narrowed segments which can be surgically corrected before thrombosis occurs. Antiplatelet drugs are of proven value in the prevention of recurrent thrombotic episodes.     

Traumatic aneurysms and arteriovenous fistulas in Nigeria

Traumatic aneurysms and arteriovenous fistulas may be as common in the developing and less industrialized countries as they are in the developed countries. In a 4 year period 12 cases of traumatic aneurysms and arteriovenous fistulas were seen at the University of Nigeria Teaching Hospital (UNTH), Enugu, Nigeria. Nine of these resulted from civilian injuries while 3 were due to military activities. The femoral vessels were involved in 7 cases while the extracranial carotid arteries were injured in 2 cases. Gunshots accounted for 6 lesions. Metal fragments and knife stabs were responsible for 2 cases respectively. All the 3 arteriovenous fistulas involved the femoral vessels--2 superficial and one deep. The vascular lesions were assessed by arteriography in 9 cases. All but one case were treated by excision, the vessels being reconstructed in 7 cases. There was one death due to septicemia.     

Multiple pulmonary arteriovenous fistulas in childhood

Three cases of multiple pulmonary arteriovenous fistulas are described in children who presented at five months, two and nine years of age. Mass spectrometry was used to measure pulmonary blood flow and, in two cases, the intrapulmonary right-to-left shunt. The shunt fractions were 51% and 35%, with no significant change on breathing 100% oxygen. In one case, effective pulmonary blood flow was measured during cardiac catheterisation by the argon-freon rebreathing method and agreed closely with that found from the Fick, principle with measured oxygen consumption. Treatment consisted of surgical ligation of a lower lobe pulmonary artery in the youngest child, balloon embolisation in the second, and initial surgical oversewing of a single large fistula followed twenty months later by steel coil embolisation in the third. The last and oldest child is well and no longer cyanosed. The first two children died seven months after treatment with evidence of progression of their pulmonary arteriovenous fistulas. The first of these, who also had an atrial septal defect and discordant thoraco-abdominal arrangement, died of heart failure. Autopsies on both children confirmed extensive involvement of both lungs by arteriovenous fistulas. In one case who had a diffuse, telangiectatic form of pulmonary arteriovenous fistulas, microscopic serial reconstructions of lung tissue revealed that anastomoses occurred between arteries accompanying terminal bronchioles and intra-acinar arteries and adjacent veins. Occlusion of the pulmonary arteries supplying the fistulas led to extensive fibrosis within them, and was associated with enlargement of the corresponding bronchial arterial circulation.