Embolotherapy for pulmonary arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

PURPOSE

To evaluate the clinical results of embolization of pulmonary arteriovenous malformations (PAVMs) in patients with hereditary hemorrhagic telangiectasia (HHT), the Rendu-Osler-Weber syndrome.

MATERIAL AND METHODS

Twelve patients in the county of Fyn, Denmark, were treated with transcatheter embolization of 20 PAVMs using 12 detachable silicone balloons and 26 steel coils.

RESULTS

All PAVMs were completely occluded and we observed a significant rise in PaO2 after treatment and a significant decrease in right-to-left shunt estimated by contrast echocardiography. All patients experienced an improved functional level. One patient experienced severe pleurisy and another a rise in temperature following treatment, but otherwise no symptomatic complications were observed.

CONCLUSION

Embolotherapy is a definitive treatment for PAVMs: it is very effective with a high success rate and few complications. Patients with HHT are at risk of PAVM and should be screened and treated for PAVMs when these reach a size that is associated with complications. In the detection of PAVMs, contrast echocardiography is a very sensitive method, and follow-up of these patients can be done with contrast echocardiography.

MR of hereditary hemorrhagic telangiectasia: prevalence and spectrum of cerebrovascular malformations

PURPOSE

Our goal was to describe the prevalence and types of cerebral vascular malformations (CVMs) seen with MR imaging in patients with hereditary hemorrhagic telangiectasia (HHT).

METHODS

We reviewed retrospectively the brain MR images of 184 consecutive patients with HHT. Catheter angiography was performed in 17 patients with CVMs detected on MR images.

RESULTS

MR imaging revealed 63 CVMs in 42 patients. Classic arteriovenous malformations (n = 10) had a conspicuous network of vessels with flow voids and enlarged adjacent pial vessels. Apparent venous malformations (n = 5) were best seen after administration of contrast material as a prominent vessel coursing through normal brain parenchyma. Indeterminate vascular malformations (n = 48) had a spectrum of appearances characterized by variable combinations of heterogeneous signal intensity, enhancement, or hemosiderin. Angiography in 17 patients revealed 47 CVMs. Forty-six were arteriovenous malformations (AVMs), including 25 CVMs not seen with MR imaging and 21 CVMs that by MR criteria included 8 AVMs and 13 indeterminate vascular malformations. Angiography confirmed 1 venous malformation seen with MR imaging but failed to detect 3 indeterminate lesions revealed by MR imaging.

CONCLUSION

MR imaging of a large cohort of consecutive patients with HHT revealed a CVM prevalence of 23% (42/184). Most CVMs (48/63) have an atypical appearance for vascular malformations on MR images. Angiographic correlation suggests that MR imaging underestimates the prevalence of CVMs and that the majority of indeterminate CVMs, despite their variable MR appearance, are AVMs.

Mutant endoglin in hereditary hemorrhagic telangiectasia type 1 is transiently expressed intracellularly and is not a dominant negative

Endoglin (CD105), a component of the TGF-beta 1 receptor complex, is the target gene for the dominantly inherited vascular disorder hereditary hemorrhagic telangiectasia type 1 (HHT1). We have identified a novel endoglin splice site mutation, leading to an in-frame deletion of exon 3, in a new-born from a family with HHT. Expression of normal and mutant endoglin proteins was analyzed in umbilical vein endothelial cells from this baby and in activated monocytes from the affected father. In both samples, only normal dimeric endoglin (160 kD) was observed at the cell surface, at 50% of control levels. Despite an intact transmembrane region, mutant protein was only detectable by metabolic labeling, as an intracellular homodimer of 130 kD. In monocytes from three clinically affected HHT1 patients, with known mutations creating premature stop codons in exons 8 and 10, surface endoglin was also reduced by half and no mutant was detected. Overexpression into COS-1 cells of endoglin cDNA truncated in exons 7 and 11, revealed their intracellular expression, inability to be secreted and to form heterodimers at the cell surface. These results indicate that mutated forms of endoglin are transiently expressed intracellularly and not likely to act as dominant negative proteins, as proposed previously. A reduction in the level of functional endoglin is thus involved in the generation of HHT1, and associated arteriovenous malformations.

Embolotherapy of large pulmonary arteriovenous malformations: long-term results

BACKGROUND

The purpose of this study was to document the long-term results of transcatheter embolotherapy of large pulmonary arteriovenous malformations (PAVMs).

METHODS

From a data base of 221 consecutive patients with PAVMs treated by embolotherapy between 1978 and 1995, 45 patients with 52 PAVMs, supplied by feeding arteries 8 mm in diameter or larger, were selected for a retrospective investigation.

RESULTS

Of 45 patients with 52 large PAVMs, 38 patients (84%) with 44 PAVMs (85%) were cured by the first embolotherapy (mean follow-up, 4.7 years). Acute periprocedural complications included self-limited pleurisy (31%), angina secondary to air embolus (2%), and paradoxical embolization of a device during deployment (4%). None of these events led to short- or long-term sequelae. Seven patients (16%) had persistence of the PAVM attributable to either recanalization (n = 4) or interim accessory artery growth (n = 3). Two of these patients presented with ischemic stroke several years after the initial treatment. Persistent PAVMs (n = 8) were retreated successfully by a second procedure (n = 7), or a third procedure (n = 1) (mean follow-up, 5.9 and 5.3 years, respectively).

CONCLUSIONS

Embolotherapy of large PAVMs results in permanent occlusion in an overwhelming majority of patients. Continued patency due to recanalization or accessory artery growth is easily detected and treated.

Pulmonary arteriovenous malformations: diagnosis and transcatheter embolotherapy

The recent long-term studies from England, France, and the Netherlands, as well as our own, indicate that transcatheter embolotherapy is definitive treatment for PAVM. More recently, Puskas et al have questioned transcatheter embolotherapy as a primary treatment for patients with PAVM (4,56). Their opinion was based on two recurrences among five patients treated with transcatheter embolotherapy. It is not clear why one of the late recurrences in the series by Puskas et al happened, and the other recurrence could have been dut to early deflation of the balloon. Nevertheless, we believe that the collective experience in the larger series reporting on transcatheter embolotherapy of PAVM supports the use of embolotherapy as a primary modality of treatment. Because many patients have bilateral pulmonary malformations and many pulmonary malformations will grow with time, repeated surgical intervention is not ideal therapy. The recurrence rate of 8% reported by Remy et al using coils, and 2% reported by Pollak et al using balloons and coils supports our contention that transcatheter embolotherapy is durable and should be the initial treatment. Also, recurrences are easily retreated by transcatheter embolotherapy with durable results (54). We favor detachable balloons over coils for occluding PAVMs because immediate cross-sectional occlusion of the segmental artery is obtained in a position that preserves the most normal branches. The necessity for repeated introduction of coils, when using the coil method, contributes to longer procedure times with an increased risk of air introduction and, in our experience, a greater risk of postprocedure pleurisy. At the same time, we appreciate that approximately 70% of PAVMs can be occluded equally well with balloons or coils. We also believe that coils have unique advantages over balloons in specific anatomic situations including oversized arteries (where coils are the only option) and for occlusion of the aneurysm of a PAVM. As with all forms of embolotherapy, the interventionalist is best served by having more than one option of treatment, which for PAVM includes both balloons and coils. In summary, PAVMs are effectively managed by means of transcatheter embolotherapy. This therapy has been demonstrated to be safe and durable. Careful technique with modifications depending on the angioarchitecture of the PAVM is required. Patients with PAVMs require follow-up at 1 month and 1 year. While observations documenting serial growth of small PAVMs are somewhat limited, there is published evidence to support their growth with time (35,36). Because of these reports and our unpublished observations, we believe that patients with treated PAVM need long-term follow-up every 5 years to detect growth of small PAVMs that will ultimately reach a size where they may cause paradoxical embolization and stroke (1).

Exceptional multiplicity of cerebral arteriovenous malformations associated with hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)

PURPOSE

To describe the clinical and imaging features of seven patients with hereditary hemorrhagic telangiectasia and an exceptional number of cerebral arteriovenous malformations (AVMs).

METHODS

One hundred thirty-six patients from a dedicated hereditary hemorrhagic telangiectasia clinic were screened systematically for cerebral AVMs by means of MR imaging. Thirty-one were found to have abnormalities suggestive of a vascular malformation. Eighteen of these 31 patients subsequently underwent diagnostic cerebral angiography.

RESULTS

Of the 18 patients who had cerebral angiography, all were found to have at least one AVM and seven were found to have three or more AVMs. The number of cerebral AVMs detected ranged from three to nine. At angiography, the AVMs varied in size from 3 to 25 mm in maximal dimension and consisted of a poorly defined plexiform nidus that typically had a single arterial feeding pedicle and a single draining vein. The two largest AVMs (20- and 25-mm nidus, respectively) contained intranidal aneurysms. Treatment included embolization, surgical excision, or follow-up management.

CONCLUSIONS

Multiple cerebral AVMs are associated with hereditary hemorrhagic telangiectasia and further highlight the uniqueness of central nervous system involvement by this systemic angiodysplasia. MR imaging can underestimate the number and size of cerebral AVMs; therefore, catheter angiography is necessary to establish the extent of central nervous system involvement in this disorder.

Management of large high-flow arteriovenous malformations of the shoulder and upper extremity with transcatheter embolotherapy

PURPOSE

To evaluate the efficacy of transcatheter embolization of arteriovenous malformations (AVMs) of the shoulder and upper extremity.

PATIENTS AND METHODS

Four men with large AVMs of the shoulder and upper extremity were treated with transcatheter arterial embolization. Symptoms included high cardiac output, pain, paresthesias, and disfigurement. Each patient underwent multiple sessions of embolotherapy.

RESULTS

In two patients there was no decrease in cardiac output. In three patients, no permanent decrease in AVM size or resolution of pain was achieved. Two patients experienced postembolization skin necrosis, and one experienced permanent radial neuropathy.

CONCLUSIONS

Large, high-flow AVMs in the shoulder and upper extremity may be relatively refractory to intravascular treatment because of the diffuse involvement of the soft tissues by the AVM and the lack of a well-defined nidus. Transcatheter embolotherapy in these lesions should be reserved for patients undergoing resection to help decrease intraoperative bleeding.

Osier Weber Rendu Syndrome: A Systemic Angiodysptasia

Educational objectives: To screen patients with epistaxis for life-threatening brain and pulmonary complications associated with Osier Weber Rendu syndrome and to have further knowledge of genetics and family history necessary to advise and treat these patients.

Life-threatening pulmonary hemorrhage with pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia

The occurrence of significant pulmonary hemorrhage associated with pulmonary arteriovenous malformations (PAVMs) and hereditary hemorrhagic telangiectasia (HHT) and the incidence of PAVMs in family members of patients with PAVMs and HHT are poorly defined. We reviewed our experience in 143 patients with PAVMs and HHT. Eleven (8 percent) of the 143 patients with HHT and PAVMs had a history of either massive hemoptysis or of hemothorax which required hospitalization. One patient died directly related to the pulmonary hemorrhage. There were four men and seven women. Three of the seven women experienced pulmonary hemorrhage during pregnancy. Seven of the 11 families participated in screening for PAVMs. Thirty-six (80 percent) of the 45 screened family members were found to have HHT. Thirteen (36 percent) of the 36 family members with HHT were proven to have PAVMs by pulmonary angiography. Pulmonary hemorrhage due to spontaneous rupture of the PAVM is a potentially life-threatening complication that should be treated aggressively with transcatheter embolotherapy. It occurs more frequently than previously recognized in patients with PAVMs and HHT. In addition, because of the increased incidence of PAVMs in family members of patients with HHT and PAVM, screening of family members with HHT is recommended especially in women of childbearing age.

Staging of mediastinal non-small cell lung cancer with FDG PET, CT, and fusion images: preliminary prospective evaluation

PURPOSE

To evaluate use of positron emission tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) in detection of mediastinal lymph node metastases from non-small cell lung cancer.

MATERIALS AND METHODS

A prospective trial to compare FDG PET and computed tomography (CT) of the thorax was performed in 23 patients with newly diagnosed or suspected non-small cell lung cancer. Blinded interpretations of CT alone, PET alone, CT and PET together, and fusion images were performed, and the results were compared with pathologic results.

RESULTS

Nineteen of 23 patients had non-small cell lung cancer. Prevalence of mediastinal involvement was 41%. In staging disease in the mediastinum, CT alone was 64% sensitive, 44% specific, and 52% accurate, whereas PET alone and fusion images were 82% sensitive, 81% specific, and 81% accurate (P < .05).

CONCLUSIONS

FDG PET was more accurate than CT in staging disease in the mediastinum in patients with lung cancer and appears to be the preferred imaging method in this clinical setting.

Clinical results of transvenous systemic embolotherapy with a neuroradiologic detachable balloon

PURPOSE

To evaluate the efficacy of transvenous systemic embolotherapy with a neuroradiologic detachable balloon.

MATERIALS AND METHODS

As part of a clinical trial, a detachable silicone balloon was used to occlude pulmonary arteriovenous malformations (PAVMs) in 35 patients and varicocele in 14 patients. In patients with PAVM, the indications for embolotherapy were prophylaxis against paradoxic embolization (n = 35) and dyspnea, fatigue, or both (n = 26); in patients with varicocele, they were pain or a discomforting lesion (n = 8) or infertility (n = 6).

RESULTS

Balloon embolotherapy was successful in 79 (98%) of the 81 lesions in which it was attempted; 29 (37%) of these 79 balloons were used in conjunction with coils. Ninety-six (97%) of 99 balloons were successfully placed; the three technical failures had no substantial clinical sequelae, and in all three, occlusion was eventually achieved with either detachable balloons or coils. Of six late deflations, five occurred in balloons placed adjacent to coils; only one, which occurred between 1 day and 21 days after placement, resulted in recanalization.

CONCLUSION

Transvenous embolization with this detachable balloon was relatively simple and provided cross-sectional occlusion of PAVMs and varicocele.

Percutaneous varicocele occlusion: long-term follow-up

PURPOSE

The authors summarize their 11-year experience with percutaneous varicocele occlusion at the Johns Hopkins Hospital.

PATIENTS AND METHODS

Data were obtained from the patients' medical records and from a mailed questionnaire. Most of the data analysis is based on the 182 patients who responded to the questionnaire.

RESULTS

Most of the occlusions were performed for infertility. The mean length of time couples had been attempting to conceive was approximately 44 months. Occlusion was technically successful in 95.7% of cases. Patients were followed up for a mean period of 59 months. Success is difficult to define because many patients and/or their wives received additional infertility treatment. Fifty-seven percent of all couples and 60% of a subgroup of couples who received no other treatment eventually conceived.

CONCLUSION

Percutaneous occlusion is a well-established treatment for varicoceles. Pregnancy rates and recurrence rates are comparable to those following surgical varicocelectomy. It is unlikely that resultant pregnancies occur from random chance alone.

Percutaneous embolotherapy of adolescent varicocele: results and long-term follow-up

PURPOSE

The authors evaluated the technical success and immediate and long-term results of percutaneous varicocele embolotherapy in the adolescent population.

PATIENTS AND METHODS

Fifty-nine adolescent patients were referred for outpatient spermatic venography and possible varicocele embolotherapy. Embolization was attempted with use of detachable balloons, coils, "sandwiched" dextrose, or a combination of these techniques. Data regarding follow-up were obtained through telephone interviews or mailed questionnaires.

RESULTS

The technical success rate for spermatic vein occlusion was 90%. Follow-up, obtained in 79% of the patients, ranged from 6 months to 8.75 years (mean, 4 years). Thirty-nine of 42 patients (93%) reported disappearance (n = 31) or only a slight, asymptomatic residual varicocele (n = 8). Three patients reported a recurrence of their varicocele. Complications occurred in three of 59 cases (5%), none had any long-term sequelae. In six cases, embolization was not feasible because of multiple collateral vessels or venous spasm.

CONCLUSIONS

Given the convenience of performing the procedure on an outpatient basis, the rapid recovery time, and long-term success and complication rates comparable to those with surgical ligation, we believe spermatic venography and percutaneous embolization is the treatment modality of choice for adolescent varicocele.

Comparison of the mechanical properties of detachable balloons for embolotherapy

PURPOSE

The forces of detachment and the durability of inflation of three different embolization balloons were compared: the Mini-balloon, the detachable silicone balloon, and the gold-valve balloon.

MATERIALS AND METHODS

Balloons were considered small (4-6 mm), medium (6-8 mm), or large (8-11 mm), depending on fully inflated diameters. Four Mini-balloons were used in each size category to compare detachment force and inflation duration against three detachable silicone balloons and three gold-valve balloons.

RESULTS

All small balloons detached with the same force, while the medium gold-valve balloon and large Mini-balloon detached with less force than their counterparts. The detachable silicone balloons had the shortest release times and a favorable detachment force profile. All balloons remained fully inflated for 11 weeks.

CONCLUSION

Most or all vessels should be adequately blocked with any of these devices.

In vivo evaluation of iophendylate-cyanoacrylate mixtures

Cyanoacrylate glue is a rapidly polymerizing agent used for vascular embolization. Polymerization occurs when the glue comes into contact with ions in the blood or on the vascular endothelium. Mixing iophendylate with cyanoacrylate causes slowing of polymerization, allowing flow-directed embolization into the nidus of an arteriovenous malformation (AVM) or the central neovascularity of a tumor or hemangioma. The authors attempted to define the relationship between the iophendylate-glue ratio and polymerization time with an in vivo swine model. In this model, glue setup occurred much more rapidly than predicted on the basis of in vitro studies. This appeared to be due to glue polymerizing on the endothelium at vessel bifurcations and at areas of acute angulation or marked vessel narrowing. On the basis of these data, the authors substantially increased the iophendylate-glue ratio in their most recent AVM embolization procedures and achieved nidus occlusion in each case. With use of the authors' guidelines, it is possible to achieve optimal distal flow-directed embolization with cyanoacrylate.