How to Treat Peripheral Arteriovenous Malformations

Arteriovenous malformations (AVMs) are direct communications between primitive reticular networks of dysplastic vessels that have failed to mature into capillary vessels. Based on angiographic findings, peripheral AVMs can be classified into six types: type I, type IIa, type IIb, type IIc, type IIIa, and type IIIb. Treatment strategies vary with the types. Type I is treated by embolizing the fistula between the artery and the vein with coils. Type II (IIa, IIb, and IIc) AVM is treated as follows: first, reduce the blood flow velocity in the venous segment of the AVM with coils; second, perform ethanol embolotherapy of the residual shunts. Type IIIa is treated by transarterial catheterization of the feeding arteries and injection of diluted ethanol. Type IIIb is treated by transarterial or direct puncture approaches. A high concentration of ethanol is injected through the transarterial catheter or direct puncture needle. When the fistula is large, coil insertion is required to reduce the amount of ethanol. Type I and type II AVMs showed the best clinical results; type IIIb showed a satisfactory response rate. However, type IIIa showed the poorest response rate, either alone or in combination with other types. Clinical success can be achieved by using different treatment strategies for different angiographic AVM types.     

脑动静脉畸形的增强MRA

3D-TOF MRA能明确瘤巢及供血动脉,但由于逐渐饱和效应的影响,小动脉及引流静脉显示不佳。CE MRA不依赖于流动效应。而和 Gd-DTPA导致的 T_1 时间缩短有关。Gd-DTPA能够抵消 3D-TOFMRA的逐渐饱和效应,本文分析了12例AVM增强 3D-TOF MRA表现。并和平扫MRA作了比较,结果表明:增强MRA对瘤巢、供血动脉及引流静脉的显示均有不同程度的提高。     

肺动静脉瘘的放射学诊断

目的 评价Ｘ线平片和心血管造影在肺动静脉瘘（ＰＡＶＭｓ）诊断中的应用及价值。材料与方法 回顾总结３０例肺动脉脉瘘病例,重点分析Ｘ线平片和心血管造影特征表现。结果 囊状肺动静瘘２１例,弥漫型肺小动静脉瘘９例。２１例囊状肺动静脉瘘中１９例具有典型Ｘ线平片征象,弥漫型肺小动静脉瘘均无典型Ｘ线平片征象。现动脉造影均清晰显示肺动静脉瘘部位、大小及范围。结论 Ｘ线平片对囊状ＰＡＶＭｓ诊断具有一定价值,弥漫型肺     

ONYX在脑血管畸形治疗中的应用

目的　报告采用液态栓塞材料 (Onyx)栓塞治疗脑动静脉畸形的初步经验。方法　采用Onyx对 17例脑动静脉畸形进行血管内栓塞治疗 ,其中 1例选择 3支血管栓塞 ,9例选择 2支血管栓塞 ,7例选择 1支血管栓塞 ,注胶时间 10～ 70min。结果　即可影像结果 :10 0 %栓塞 5例 ,70 %以上 5例 ,70 %以下 7例。并发症 :术后出血 2例 ,微导管不能拔除 1例。结论　ONYX栓塞脑动静脉畸形与NBCA相比具有在畸形团内弥散好、注胶时间长、一次栓塞的畸形团多和安全性高等优点 ,但需要进一步积累经验 ,提高疗效。     

脊髓动静脉畸形的MRI表现

本文报道5例脊髓动静脉畸形的MRI表现，畸形血管位于颈段1例，胸段1例，胸腰段3例，4例畸形血管位于脊髓背侧，1例位于脊髓腹侧，背侧及髓内，脊髓动静脉畸形的MRI特征性表现为：髓内或脊髓表面点，条状无信号影，与传统影像学方法相比，MRI在诊断脊髓动静脉畸形上具有无创伤，显示病变更全面，直观，便于随访观察的优点。     

Treatment Outcomes of Embolization for Peripheral Arteriovenous Malformations

PurposeTo evaluate treatment outcomes of embolization for peripheral arteriovenous malformations (AVMs) in a tertiary referral center where ethanol is the primary agent of choice.MethodsA retrospective study was performed of 93 patients (median age, 31 years; range, 2–66 years) with peripheral AVMs treated with embolization (n = 442; median, 2 per patient; range, 1–82) between January 2010 and July 2016. Ethanol was used in most cases (n = 428; 97%). AVMs were classified as type I (n = 3), type II (n = 57), type IIIa (n = 5), type IIIb (n = 15), and type IV (n = 13) according to the Yakes classification system. Effectiveness of embolization was based on AVM devascularization on angiography: 100% (total), 90%–99% (near-total), 70%–90% (substantial), 30%–70% (partial), and 0%–30% (failure). Complications were graded according to the Society of Interventional Radiology classification.ResultsIn 69% of patients, 70%–100% devascularization was achieved. Total and near-total occlusion of the nidus were more often achieved in AVMs of types I and IIIa (both 100%) than in AVMs of types II, IIIb, and IV (56%, 67%, and 39%, respectively; P = .019). A total of 109 complications were identified: 101 minor (22.9%) and 8 major (1.8%). Major complications included wounds (n = 5), false aneurysm (n = 1), finger contracture (n = 1), and severe pain (n = 1) requiring therapy. The patient complication risk was significantly affected by the number of procedures (relative risk = 2.0; P < .001). Age, AVM location, and angioarchitecture type did not significantly affect complication risk.ConclusionsAVM embolization resulted in 70%–100% devascularization in 69% of patients, with few major complications. This study indicates that the type of AVM angioarchitecture affects the number of procedures needed and the achievability of AVM devascularization.     

肺动静脉畸形的临床与比较影像学

肺动静脉畸形(pulmonary arteriovenous mRlformations,PAVM)是肺动脉和肺静脉之间的异常沟通,又称为肺动静脉瘘、肺血管瘤、肺动静脉血管瘤、肺动静脉瘤、肺血管错构瘤等[1].它是罕见的肺部疾病,无潜在恶性.自1897年Churton在尸检中首次发现至今,文献报道共500余例.     

旋转式伽玛刀治疗脑动静脉畸形

目的：评估旋转式伽玛刀对脑动静脉畸形的治疗效果及术后并发症。方法：1996年11月－2000年5月以旋转式伽玛刀治疗脑动静脉畸形。脑动静脉畸形平均直径23mm。脑动静脉畸形周边平均照射剂量19．2Gy(13-25Gy),中心平均照射剂量37．6Gy(32.5-50Gy）。结果：106例病人有完整的随访资料，平均随访18．4个月（5－44个月）。5例病人（4．2％）伽玛刀治疗后5－13个月发生再出血，无死亡。78例病人治疗后行CT或MR检查，19例（22％）出现放射性水肿，多发生在治疗后6－18个月，一般经类固醇激素治疗，数月可消退，无遗留永久并发症。68例病人随访超过1年，其中57例在治疗后1年行脑血管造影复查，24例（42％）畸形血管完全闭塞。27例随访超过2年，其中23例行脑血管造影检查，18例（78％）完全闭塞。结论：旋转式伽玛刀是一种新的可靠的立体定向治疗设备，对脑动静脉畸形具有较高的治愈率，治疗后并并发症少且极少出现永久性并发症。     

经导管血管内栓塞术治疗肺动静脉畸形

目的 评价经皮穿刺经导管栓塞术治疗肺动静脉畸形(PAVMs)的安全性和疗效。资料与方法 对10例PAVMs患者进行了经导管栓塞治疗,男4例,女6例,平均年龄12岁(6个月～28岁),均为先天性。临床表现有紫绀和杵状指／趾7例,劳力性呼吸困难6例,胸部血管杂音4例,咯血2例和心功能不全2例。栓塞时用微型钢丝圈2例,普通钢丝圈8例。结果 PAVMs病灶为多发性7例,单发性3例。10例共做栓塞治疗12次,技术成功率为100％,治疗结束时复查肺动脉造影显示单发病灶完全消失,多发病灶者主要异常血管不再显影。术后血氧饱和度从平均78％增至96％。2例术前存在心功能不全,术后症状消失;胸部血管杂音消失。术后出现轻微胸痛5例,少量胸腔积液3例;1例术后2个月死于栓塞肺叶肺梗死继发化脓性感染。9例随访18个月～9年,一般情况良好,日常生活正常,无神经系统症状和体征,除2例弥漫型动静脉畸形血氧饱和度持续在85％～90％外,其余缺氧症状未再复发。结论 经导管血管内栓塞术是治疗PAVMs的安全、有效方法。     

Diagnostic Yield of Rescreening Adults for Pulmonary Arteriovenous Malformations

PurposeTo determine the yield of rescreening adult hereditary hemorrhagic telangiectasia (HHT) patients with initial negative screening CT for pulmonary arteriovenous malformations (PAVMs).Materials and MethodsPatients with a definite diagnosis of HHT were identified in the University of Toronto, Université de Montréal, and Mayo Clinic HHT databases. Inclusion criteria were: (i) definite diagnosis of HHT; (ii) initial negative PAVM screening based on bubble echocardiography and/or chest CT; and (iii) minimum 2-year imaging follow-up. A positive rescreen was defined as a newly detected PAVM on follow-up CT. Frequency of new PAVMs was calculated at 3 ± 1 years, 5 ± 1 years, 7–9 years, and ≥10 years. The primary endpoint was the rate of new PAVMs at 5 ± 1 years.ResultsOne hundred seventy-two patients (mean age, 49.6 ± 16.7 years; 59% female) were followed for a median of 7 years. Nine patients (5.2%) had newly detected PAVMs. At the 3-, 5-, 7-, and ≥10-year time points, the cumulative rate of newly detected PAVMs was 1.8% (3/166), 5.0% (7/140), 8.8% (8/91), and 13.8% (9/65), respectively. Median feeding artery diameter was 1.3 mm. One patient had a feeding artery larger than 3 mm discovered after 6 years and was treated with embolization. The overall rate of newly detected PAVMs was 0.7%/patient-year.ConclusionsThere is a definite but low rate of newly detected PAVMs in HHT patients with initial negative screening studies. No new treatable PAVMs were identified at the 5-year mark, although 1 treatable case was identified after 6 years. These findings suggest that a longer screening interval may be warranted.     

Hemorrhagic Complications after Endovascular Treatment of Cerebral Arteriovenous Malformations

BACKGROUND AND PURPOSE:Intracranial hemorrhage is the most severe complication of brain arteriovenous malformation treatment. We report our rate of hemorrhagic complications after endovascular treatment and analyze the clinical significance and potential mechanisms, with emphasis on cases of delayed hemorrhage after uneventful embolization.MATERIALS AND METHODS:During a 10-year period, 846 embolization procedures were performed in 408 patients with brain AVMs. Any cases of hemorrhagic complications were identified and divided into those related or unrelated to a periprocedural arterial tear (during catheter navigation or catheter retrieval). We analyzed the following variables: sex, age, hemorrhagic presentation, Spetzler-Martin grade, size of the AVM, number of embolized pedicles, microcatheter used, type and volume of liquid embolic agent injected, and the presence of a premature venous occlusion. Univariate and multivariate multiple regression analyses were performed to identify risk factors for hemorrhagic complications.RESULTS:A hemorrhagic complication occurred in 92 (11%) procedures. Forty-four (48%) complications were related to a periprocedural arterial perforation, and 48 (52%) were not. Hemorrhagic complications unrelated to an arterial perforation were located more commonly in the cerebral parenchyma, caused more neurologic deficits, and were associated with worse prognosis than those in the arterial perforation group. Only premature venous occlusion was identified as an independent predictor of hemorrhagic complication in the nonperforation group. Premature venous occlusion was significantly related to the ratio of Onyx volume to nidus diameter.CONCLUSIONS:Higher injected volume of embolic agent and deposition on the venous outflow before complete occlusion of the AVM may account for severe hemorrhagic complications.

Treatment of cerebral arteriovenous malformation is challenging and requires a multidisciplinary approach involving surgery with AVM removal, endovascular treatment (EVT) with embolization, or radiosurgery. Each technique can be combined and has its own advantages and complications. A conservative approach is an important aspect of the management of AVMs. EVT can be used for presurgical or preradiosurgical treatment of AVMs or as a stand-alone procedure for curative purposes. Onyx (Covidien, Irvine, California) is currently the most commonly used embolic agent; in some instances, cyanoacrylate glue can be used. The most serious complication of AVM embolization is hemorrhage, reported in 4%–15% of patients treated by EVT.^1–3 The group of patients who experience delayed hemorrhage after EVT remains poorly understood, with multiple classifications^4–6 and explanations^7–9 and deserves further study. To investigate the potential mechanisms of hemorrhages following EVT, we report our rate of hemorrhagic complications (HCs) and their clinical significance and focus on those not related to an arterial lesion secondary to navigation or microcatheter retrieval.     

Retrograde Transvenous Ethanol Embolization of High-flow Peripheral Arteriovenous Malformations

Purpose

To report the clinical efficiency and complications in patients treated with retrograde transvenous ethanol embolization of high-flow peripheral arteriovenous malformations (AVMs). Retrograde transvenous ethanol embolization of high-flow AVMs is a technique that can be used to treat AVMs with a dominant outflow vein whenever conventional interventional procedures have proved insufficient.

Methods

This is a retrospective study of the clinical effectiveness and complications of retrograde embolization in five patients who had previously undergone multiple arterial embolization procedures without clinical success.

Results

Clinical outcomes were good in all patients but were achieved at the cost of serious, although transient, complications in three patients.

Conclusion

Retrograde transvenous ethanol embolization is a highly effective therapy for high-flow AVMs. However, because of the high complication rate, it should be reserved as a last resort, to be used after conventional treatment options have failed.