Pulmonary arteriovenous malformations in children: outcomes of transcatheter embolotherapy

OBJECTIVE

To describe outcomes of transcatheter embolotherapy (TCE) in children with pulmonary arteriovenous malformations (PAVMs).

STUDY DESIGN

Chart and imaging review of all children (age </=18 years) treated for PAVMs by TCE at three hereditary hemorrhagic telangiectasia centers.

RESULTS

All 42 treated patients were included, with a mean age of 12 years (range, 4 to 18). Cyanosis was present in 25 of 42 patients (60%). Hemoptysis had occurred in 3 of 42 patients (7%) and neurologic complications (stroke, cerebral abscess) occurred in 8 patients (19%) before assessment. PAVMs were focal in 30 of 42 (71%) and diffuse in 12 of 42 (29%) patients. TCE was performed for 172 PAVMs and 35 diffuse regions (regional TCE). Follow-up was obtained in 38 of 42 (90%) patients (mean, 7 years). After TCE in patients with focal PAVMs, oxygenation improved significantly, with no further complications from the PAVMs. Reperfusion was noted in 23 of 153 (15%) PAVMs. Eighteen of 23 (78 %) of these were retreated, with documented aneurysmal involution in 10 of 13 (77%) patients. TCE complications included pleuritic chest pain (24% of sessions) and deployment complications (device paradoxical embolization or device misplacement) (3% of sessions, 1% of PAVMs), with no long-term complications.

CONCLUSIONS

PAVMs cause life-threatening complications in children; treatment with TCE is safe, with complication rates comparable to adult rates.

Micronester—A New Pushable Fibered Microcoil for Embolotherapy

A prototype 0.018 pushable fibered microcoil with an extended length of 14 cm was developed and used successfully for the first time to treat a patient with bilateral varicocele. This new coil provides immediate cross-sectional occlusion when "nested" into a densely packed coil mass. Potential uses of this new microcoil are discussed.

Angiography of hepatic vascular malformations associated with hereditary hemorrhagic telangiectasia

PURPOSE

To describe the angiographic features of hepatic involvement in hereditary hemorrhagic telangiectasia (HHT), particularly the presence of portovenous shunts.

METHODS

We reviewed the angiographic findings of seven patients with HHT. The patients comprised three women and four men with a mean age of 51 years.

RESULTS

Intrahepatic telangiectasias were found in all seven patients and shunts between three vascular channels were found in six of seven patients. In the four patients who had portovenous shunts combined with arterioportal shunts, the portovenous shunts were large. Three patients had no portovenous shunts. Two of these patients had arteriovenous shunts, and one had no shunt. The mean age (69 years) of the patients with portovenous shunts was older than those without portovenous shunts (26 years).

CONCLUSIONS

Hepatic vascular lesions in HHT are varied, ranging from telangiectasias to large shunts between three vascular channels. In an advanced stage of involvement, large portovenous shunts are present.

Diagnosis and management of gastrointestinal bleeding in patients with hereditary hemorrhagic telangiectasia

OBJECTIVE

Our aim was to report our experience with treating GI bleeding in patients with hereditary hemorrhagic telangiectasia (HHT).

METHODS

Consecutive patients with GI bleeding referred to the Yale University Vascular Malformation Center underwent clinical evaluation and endoscopy. Hb and blood transfusion requirements for 1 yr before and after evaluation were documented. Patients with a mean Hb <or= 8 mg/dl or blood transfusion requirements >or= 12 units packed red blood cells (PRBC)/yr were defined as patients with significant bleeding. Drug therapies, including ethinyl estradiol/norethindrone, danazol, and aminocaproic acid, were prescribed on an individual patient basis.

RESULTS

The study included 43 HHT patients with a mean age of 57 yr. Endoscopy revealed telangiectases in the esophagus (1/41), stomach (33/41), duodenum (33/41), jejunum (5/9), and colon (10/32). Patients with > 20 telangiectases visualized on esophagogastroduodenoscopy had a significantly lower mean Hb of 7.9, compared with 9.4 (p = 0.007), and a trend toward higher blood transfusion requirements. Non-HHT-related causes of GI bleeding were diagnosed in four patients. During a mean follow up of 18.9 months, the group of 40 patients with HHT-related bleeding had improvements in their mean Hb and blood transfusion requirements.

CONCLUSIONS

Some HHT patients with GI bleeding improve on drug therapies, but others fail. Transfusion-dependent GI bleeding is difficult to manage, and optimal management may include both medical and endoscopic treatments.

Vein of Galen technique for occluding the aneurysmal sac of pulmonary arteriovenous malformations

In seven of 255 consecutive patients (2.7%) who underwent pulmonary arteriovenous malformation (PAVM) embolization at our center between July 1, 1996, and July 1, 2000, the feeding artery was considered too short for safe occlusion with use of standard stainless-steel coils or detachable balloons. These patients were successfully treated with use of a modified vein of Galen technique similar to the one used for managing intracranial vein of Galen aneurysms. In this article, the authors report their experience with this technique in safely occluding the aneurysmal sacs of PAVMs in patients with short (<2 cm) feeding pulmonary arteries.

The 1st balloon valvuloplasty: an historical note

Balloon valvuloplasty (BV) is currently the treatment of choice for pulmonic stenosis in humans and dogs. Before permission was obtained to attempt the 1st BV in a child in 1982, the safety and efficacy of the procedure were tested in 1980 in an English Bulldog with spontaneous pulmonic stenosis. A fatal outcome would have caused indefinite postponement of BV in human patients, a procedure that currently benefits over 25,000 patients a year worldwide. This article describes the initial test procedure and its fortunate outcome in spite of unrecognized coronary anomalies in the bulldog. A small balloon was used in the test procedure, and fatal disruption of the anomalous left coronary artery (CA) did not occur as it has in several bulldogs since that time.

The use of cyanoacrylate adhesives in peripheral embolization

Although liquid adhesives or glue have been used as embolic agents for nearly three decades, experience with them outside of neurointerventional indications is generally limited. Cyanoacrylates are the main liquid adhesives used in the vascular system and have an important role in managing vascular abnormalities, especially arteriovenous malformations. Vascular occlusion results as these agents polymerize on exposure to the ions in blood. A description of the properties, biologic interactions, techniques of use, and indications for acrylic embolization in the peripheral circulation is especially pertinent at this time because of the recent approval of n-butyl cyanoacrylate by the United States Food and Drug Administration.

Transcatheter embolotherapy of maternal pulmonary arteriovenous malformations during pregnancy

STUDY OBJECTIVES

To determine if transcatheter embolotherapy is safe and effective for the treatment of pulmonary arteriovenous malformations during pregnancy.

DESIGN

Prospective study.

SETTING

Specialized hereditary hemorrhagic telangiectasia centers at Yale University School of Medicine and St. Michael's Hospital, University of Toronto.

PATIENTS

Seven pregnant women (age range, 24 to 34 years; gestational age range, 16 to 36 weeks) undergoing transcatheter embolotherapy.

INTERVENTIONS

Transcatheter embolotherapy in all patients.

MEASUREMENTS AND RESULTS

Thirteen pulmonary arteriovenous malformations in seven patients were embolized with detachable silicone balloons and/or stainless steel coils without incident. The estimated fetal radiation dose ranged from < 50 to 220 mrad. No complications of pulmonary arteriovenous malformations occurred in any of the patients after transcatheter embolotherapy. The mothers went on to deliver healthy babies in all cases.

CONCLUSIONS

Transcatheter embolotherapy of maternal pulmonary arteriovenous malformations performed by an experienced radiologist appears to be safe and effective after 16 weeks of gestational age.

Long-term outcome of embolotherapy and surgery for high-flow extremity arteriovenous malformations

PURPOSE

To assess the long-term efficacy of embolotherapy in combination with surgery for management of symptomatic high-flow arteriovenous malformations (HFAVMs) of the lower and upper extremities.

MATERIALS AND METHODS

Twenty consecutive patients with symptomatic high-flow lower extremity AVMs (LE-AVMs; n = 9) and upper extremity AVMs (UE-AVMs; n = 11) were treated from 1982 to 1999. All nine patients with LE-AVM had pain and seven had ulceration of the skin. All 11 patients with UE-AVM had debilitating pain, seven had weakness of the affected hand, and two had bony erosion. Embolization of the nidus beneath the site of maximum pain or ulceration was performed percutaneously from the femoral artery through coaxially placed microcatheters (n = 18) or surgical cutdown (n = 2). Cyanoacrylate (isobutyl or n-butyl) diluted with iophendylate or ethiodized oil was used in 19 of 20 patients.

RESULTS

Follow-up was completed in eight of nine patients with LE-AVM (mean, 8.6 y) and nine of 11 patients with UE-AVM (mean, 7.4 y) after treatment. One patient with localized LE-AVM was functioning well 13 years after embolotherapy and another was functioning well 16 years after undergoing three embolotherapy procedures and two skin grafts. Five of nine patients with LE-AVM required below-the-knee (n = 4) or above-the-knee (n = 1) amputation 1-6 years after technically and clinically successful embolotherapy. All three trifurcation arteries were diffusely involved in HFAVM in patients requiring amputation. Healing of the two amputation sites, involved by AVM at the knee, was excellent after preoperative geniculate artery embolotherapy. All 11 patients with UE-AVM experienced marked symptomatic improvement; seven after embolotherapy alone and the other four after resection of AVM. One complication of digital spasm was reversed by administration of nerve blocks.

CONCLUSIONS

LE-AVM with diffuse involvement of all three trifurcation arteries ultimately required amputation because of recurrence of symptoms after technically and clinically successful embolotherapy. Cyanoacrylate embolotherapy alone or in combination with surgical resection of the AVM provided excellent long-term palliation in patients with UE-AVM.

Pulmonary arteriovenous malformations: cerebral ischemia and neurologic manifestations

BACKGROUND

There is an increasingly recognized association between pulmonary arteriovenous malformations (PAVM) and cerebral ischemia, frequently attributed to paradoxical embolization. PAVM occur in 20 to 30% of the hereditary hemorrhagic telangiectasia (HHT) population.

OBJECTIVE

To evaluate the risk determinants for cerebral ischemia and neurologic manifestations in patients with PAVM.

METHODS

A retrospective cross-sectional study was performed on consecutive patients admitted between 1988 and 1992 for treatment of PAVM. The number of PAVM, feeding artery (FA) diameters, and aneurysmal sizes were determined by pulmonary angiography. Patients were categorized as having single or multiple PAVM with an FA diameter of > or = 3 mm. History, examination, and cerebral imaging studies were used to determine the prevalence of neurologic manifestations. Patients were defined as having cerebral paradoxical embolization if there was radiologic evidence of cortical infarction.

RESULTS

There were 75 cases: 26 single PAVM and 49 multiple PAVM. Cortical infarction was present in 14% of patients with single PAVM. Patients with multiple PAVM had a greater prevalence of any infarction (OR 3.2; 95% CI, 1.2 to 9.44, p = 0.030), cortical infarctions (OR 2.3; 95% CI, 0.58 to 9.2, p = 0.230), subcortical infarctions (OR 2.1; 95% CI, 0.58 to 7.95, p = 0.249), abscesses (OR 2.3; 95% CI, 0.46 to 11.94; p = 0.295), and seizures (OR 6.4, 95% CI 0.77 to 53.2, p = 0.054). Patients with multiple PAVM had markedly greater odds of having any clinical or radiologic evidence of cerebral ischemic involvement (OR 4.5; 95% CI, 1.47 to 14; p = 0.008).

CONCLUSION

There is a strong association between single PAVM and various neurologic manifestations. The prevalence is greater for patients with multiple PAVM, suggesting increased predisposition for paradoxical embolization with a greater number of malformations.

Liver disease in patients with hereditary hemorrhagic telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia, or Rendu-Osler-Weber disease, is an autosomal dominant disorder characterized by angiodysplastic lesions (telangiectases and arteriovenous malformations) that affect many organs. Liver involvement in patients with this disease has not been fully characterized.

METHODS

We studied the clinical findings and results of hemodynamic, angiographic, and imaging studies in 19 patients with hereditary hemorrhagic telangiectasia and symptomatic liver involvement.

RESULTS

We evaluated 14 women and 5 men who ranged in age from 34 to 74 years. All but one of the patients had a hyperdynamic circulation (cardiac index, 4.2 to 7.3 liters per minute per square meter of body-surface area). In eight patients, the clinical findings were consistent with the presence of high-output heart failure. The cardiac index and pulmonary-capillary wedge pressure were elevated in the six patients in whom these measurements were performed. After a median period of 24 months, the condition of three of the eight patients had improved, four were in stable condition with medical therapy, and one had died. Six patients had manifestations of portal hypertension such as ascites or variceal bleeding. The hepatic sinusoidal pressure was elevated in the four patients in whom it was measured. After a median period of 19 months, the condition of two of the six patients had improved, and the other four had died. Five patients had manifestations of biliary disease, such as an elevated alkaline phosphatase level and abnormalities on bile duct imaging. After a median period of 30 months, the condition of two of the five had improved, the condition of one was unchanged, heart failure had developed in one, and one had died after an unsuccessful attempt at liver transplantation.

CONCLUSIONS

In patients with hereditary hemorrhagic telangiectasia and symptomatic liver-involvement, the typical clinical presentations include high-output heart failure, portal hypertension, and biliary disease.

Embolotherapy in the bronchial and pulmonary circulations

This two-part article first discusses the role of bronchial artery transcatheter embolotherapy in the management of patients with hemoptysis. Following this discussion, the authors review pulmonary arteriovenous malformations, their embolization, follow-up protocols, and outcome criteria as currently practiced at the authors' Vascular Malformation Center.

Diffuse pulmonary arteriovenous malformations: characteristics and prognosis

OBJECTIVE

To study the clinical characteristics and prognosis of patients with diffuse pulmonary arteriovenous malformations (AVMs).

DESIGN

Retrospective chart review of all patients (n = 16) with diffuse pulmonary AVMs seen at Yale New Haven Hospital, Johns Hopkins Hospital, and St. Michael's Hospital. Up-to-date follow-up information was obtained in all living patients.

RESULTS

All patients were severely hypoxic. Neurologic complications (stroke or brain abscess) had occurred in 70% of patients by the time of diagnosis. During the follow-up period (mean, 6 years), three patients died and two others developed new neurologic complications. One of the deaths occurred perioperatively during lung transplantation. All patients underwent transcatheter embolotherapy of any large pulmonary AVMs. A selected group underwent pulmonary flow redistribution, a novel technique. Oxygenation did not improve significantly with embolotherapy of the larger AVMs, but there was a small significant improvement in those patients who underwent pulmonary flow redistribution. The majority (85%) of the living patients are currently working or studying full-time.

CONCLUSIONS

Patients with diffuse pulmonary AVMs are at increased risk of neurologic complications. Transcatheter embolotherapy does not significantly improve the profound hypoxia, but it may reduce the risk of neurologic complications. Antibiotic prophylaxis is recommended for bacteremic procedures to prevent brain abscess. These patients can live for many years and lead productive lives. We do not recommend lung transplantation because survival with disease is difficult to predict and we have observed a perioperative transplant death.

Identification of hereditary hemorrhagic telangiectasia type 1 in newborns by protein expression and mutation analysis of endoglin

Hereditary hemorrhagic telangiectasia (HHT) is a dominantly inherited vascular disorder that is heterogeneous in terms of age of onset and clinical manifestations. Endoglin is the gene mutated in HHT1, which is associated with a higher prevalence of pulmonary arteriovenous malformations than HHT2, where ALK-1 is the mutated gene. Endoglin is constitutively expressed on endothelial cells and inducible on peripheral blood activated monocytes so that protein levels can be measured by metabolic labeling and immunoprecipitation. We report the analysis of umbilical vein endothelial cells in 28 newborns from 24 families with a clinical diagnosis of HHT. Reduced levels of endoglin were observed in umbilical vein endothelial cells in 15/28 subjects and in activated monocytes of all clinically affected relatives tested, suggesting that these individuals had HHT1. No mutant protein was expressed at the cell surface in any of these cases, and a transient intracellular species was seen in samples of only two families, supporting a haploinsufficiency model. Quantitative multiplex PCR fragment analysis was established for the endoglin gene and revealed six mutations that were confirmed by automated DNA sequencing. An additional 10 mutations were identified in newborns by sequencing all exons. Of the 16 mutations, 10 were novel, three had been independently identified in related families, and three were previously known. Our data confirm that endoglin levels correlate with the presence or absence of mutation in HHT1 families, allowing the early identification of affected newborns that should be screened clinically to avoid serious complications of this disorder, such as cerebral arteriovenous malformations.

Embolotherapy of pulmonary arteriovenous malformations with detachable balloons: long-term durability and efficacy

PURPOSE

To determine long-term durability and efficacy of pulmonary arteriovenous malformation (PAVM) embolotherapy using detachable gold valve latex (GVB) and silicone balloons (DSB).

MATERIALS AND METHODS

Eighty-two patients were treated with either GVBs or DSBs between 1991 and 1996. Complete follow-up, consisting of chest radiography or high-resolution chest computed tomography, was obtained in each patient between 1996 and 1998. The PAVM was considered cured if the aneurysmal portion was involuted with or without a small residual scar.

RESULTS

Eighty-two of the 85 DSBs (96%) were inflated 2-4 years later, and none of the 56 GVBs remained inflated 1-3 years after placement. Despite early deflation of the GVB (91% at 1 month), only one PAVM persisted in both groups (DSB and GVB). Clinical and radiographic involution of the PAVMs was complete in all patients except one, who was easily re-treated. No migration of DSBs or GVBs to the systemic circulation occurred.

CONCLUSIONS

DSBs and GVBs provide immediate cross-sectional occlusion of PAVM and are equally effective in "curing" the PAVM. The DSBs remain inflated 2-4 years after placement provided isoosmotic contrast material is used to inflate them and volume recommendations are adhered to. No early or late migration of the DSB or GVB occurs, provided they are securely placed.