Embolization of pulmonary arteriovenous malformations with amplatzer vascular plugs: safety and midterm effectiveness

Transarterial Embolization of Simple Pulmonary Arteriovenous Malformations: Long-Term Outcomes of 0.018-Inch Coils versus Vascular Plugs

PURPOSE

To compare the safety, effectiveness, and persistence rates of 0.018-inch coils with those of Amplatzer vascular plugs (AVPs; Abbott Vascular, Abbott Park, Illinois) for the treatment of pulmonary arteriovenous malformations (PAVMs) in response to a growing concern that 0.018-inch coil embolization would increase the long-term persistence rate.

MATERIALS AND METHODS

This is a retrospective, single-center study of a database (2002-2020) of 633 PAVM embolizations. Complex PAVMs and those not embolized with 0.018-inch coils or plugs were excluded. PAVM embolization material was classified into 4 groups: (a) 0.018-inch nonfibered coils (NFCs), (b) 0.018-inch fibered coils (FCs), (c) NFCs and FCs, or (d) plugs. Persistence was defined as flow through the PAVM on digital subtraction angiography (DSA) or as <30% diameter reduction of the aneurysmal sac on unenhanced computed tomography (CT). Kaplan-Meier analysis and Cox regression were used to assess PAVM's persistence-free survival.

RESULTS

A total of 312 PAVM embolizations with NFCs (43 PAVMs), FCs (127 PAVMs), NFCs and FCs (12 PAVMs), or plugs (130 PAVMs) in 109 patients (28% men; mean age = 49 years) were included. All PAVM embolizations were technically successful without any major adverse events. PAVM persistence-free survival rates at 10 years' follow-up were 40.8% versus 44.7% in the NFC and FC groups (P = .22) and 47.3% versus 81.0% in the 0.018-inch coil (NFC or FC) and plug groups (P < .0001), respectively. There were 0.43 (79/182) and 0.08 (10/130) re-embolization procedures per PAVM in the 0.018-inch coil and plug groups, respectively (P < .001).

CONCLUSIONS

PAVM embolization with 0.018-inch coils was safe, but persistence rate with PAVM embolization was significantly higher than that with plugs, with no significant differences between FCs and NFCs.

Retrospective single-arm cohort study of video-assisted thoracic surgery for treatment of idiopathic peripherally located simple type pulmonary arteriovenous malformation in 23 consecutive patients

BACKGROUND

Although case reports of video-assisted thoracic surgery (VATS) for pulmonary arteriovenous malformation (PAVM) have been published, studies analyzing more than 10 cases were limited. A retrospective single-arm cohort study was performed to investigate the efficacy of VATS in 23 consecutive patients with idiopathic peripherally located simple type PAVM.

METHODS

VATS was performed for wedge resection of 24 PAVMs in 23 patients, which included 4 males and 19 females with an age range of 25 to 80 years (mean: 59.6 ± 13.0). Two patients underwent simultaneous resection of lung carcinoma, one by wedge resection and another by lobectomy. Each medical record was analyzed according to the resected specimen, bleeding volume, postsurgical hospital stay length, duration of chest tube placement, and VATS time. The distance between pleural surface/fissure and PAVM was measured on CT, and the influence of this distance on identification of PAVM was investigated.

RESULTS

In all 23 patients, VATS was successfully performed, and the venous sac was included in each resected specimen. Bleeding volume was less than 10mL in all but one with 1900 mL bleeding volume due to simultaneous lobectomy for carcinoma, not wedge resection of PAVM. Postsurgical hospital stay length, duration of chest tube placement, and VATS time were 5.0 ± 1.4 days, 2.7 ± 0.7 days, and 49.3 ± 39.9 min, respectively. In 21 PAVMs with a distance of 1 mm or less, purple vessel or pleural bulge of PAVM was identified soon after insertion of a thoracoscope. In the remaining 3 PAVMs with a distance of 2.5 mm or more, additional efforts were needed for identification.

CONCLUSION

VATS was found to be a safe and effective to treatment for idiopathic peripherally located simple type PAVM. When the distance between pleural surface/fissure and PAVM was 2.5 mm or more, a plan and strategy for identification of PAVM should be prepared before VATS.

An Update on Embolization for Pulmonary Arteriovenous Malformations

Pulmonary arteriovenous malformations are abnormal connections between a pulmonary artery and a pulmonary vein that can lead to ischemic stroke and brain abscess due to right-to-left shunting of blood. Embolization is currently considered the first treatment option for pulmonary arteriovenous malformations owing to its minimal invasiveness. This review updates the indications and techniques for the embolization of pulmonary arteriovenous malformations and determines the persistence of pulmonary arteriovenous malformations following embolization based on the most recent literature.

Update on pulmonary arteriovenous malformations

This review aimed to provide an overview of pulmonary arteriovenous malformations, including the major clinical and radiological presentations, investigation, and treatment algorithm of the condition. The primary etiology of pulmonary arteriovenous malformations is hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome, with mutations in the ENG gene on chromosome 9 (HHT type 1) or in the ACVRL1/ALK1 complex (HHT type 2). Epistaxis should always be evaluated when repeated, when associated with anemia, and in some cases of hypoxemia. In the investigation, contrast echocardiography and chest CT are essential for evaluating this condition. Embolization is the best treatment choice, especially for correction in cases of hypoxemia or to avoid systemic infections. Finally, disease management was addressed in special conditions such as pregnancy. CT follow-up should be performed every 3-5 years, depending on the size of the afferent and efferent vessels, and antibiotic prophylactic care should always be oriented. Ultimately, knowledge of the disease by health professionals is a crucial point for the early diagnosis of these patients in clinical practice, which can potentially modify the natural course of the disease.

Postembolization Persistence of Pulmonary Arteriovenous Malformations: A Retrospective Comparison of Coils and Amplatzer and Micro Vascular Plugs Using Propensity Score Weighting

BACKGROUND. Endovascular embolization of pulmonary arteriovenous malformations (PAVMs) was historically performed with embolic coils. The Amplatzer Vascular Plug device (AVP) was introduced for this purpose in 2007 and the Micro Vascular Plug device (MVP) in 2013. OBJECTIVE. The purpose of this study was to compare coils, AVPs, and MVPs in terms of risk of persistence after PAVM embolization by use of propensity score weighting to account for biases in device selection. METHODS. This retrospective study included 112 patients (78 women and girls, 34 men and boys; mean age, 45 years) who underwent embolization of 393 PAVMs with a single device type (coil, MVP, or AVP) from January 2003 to January 2020. Persistence was defined as less than 70% reduction in PAVM sac size or contrast enhancement of the sac on follow-up pulmonary CTA. A Cox proportional hazards regression model was used to assess associations between embolic device selection and PAVM persistence. Inverse propensity score weighting was used to account for differences in embolic device selection based on patient and PAVM characteristics. RESULTS. The median postembolization follow-up period was 1.5 years (IQR, 0.3-5.6 years). Persistence was found in 10% (41/393) of PAVMs, including 16% (34/207) of those treated with coils, 8% (7/88) of those treated with AVPs, and 0% (0/98) of those treated with MVPs. Variables associated with embolization device (p < .25) were age, sex, pediatric versus adult status, smoking status, PAVM complexity, PAVM laterality, number of feeding arteries, and feeding artery diameter. The Cox regression model incorporated inverse propensity score weighting to account for the differences between treatment groups in these variables and incorporated feeding artery diameter because of imbalance remaining after weighting. With coils as the referent, MVPs had a hazard ratio for persistence of less than 0.01 (95% CI, < 0.01 to < 0.01; p < .001), and AVPs had a hazard ratio of 0.37 (95% CI, 0.16-0.90; p = .03). CONCLUSION. The risk of persistence after PAVM embolization was significantly lower for MVPs alone than for coils or AVPs alone. In addition, the risk of persistence was lower for AVPs than for coils. CLINICAL IMPACT. The findings support the clinical use of MVPs as the preferred device for PAVM embolization over coils and polytetrafluoroethylene-covered plugs.

Pulmonary Arteriovenous Malformations: What the Interventional Radiologist Should Know

Pulmonary arteriovenous malformations (PAVMs) are abnormal connections between the pulmonary artery and pulmonary vein bypassing the normal capillary bed causing a right-to-left shunt. The majority (80-90%) of PAVMs are associated with hereditary hemorrhagic telangiectasia (HHT). PAVMs may be asymptomatic or present with symptoms of hypoxia, shortness of breath, migraines, sequelae of paradoxical embolization, or rupture. Transcatheter embolization has become the standard of care. This article will review the clinical presentation, workup, genetics, imaging findings, embolization, complications, and follow-up for patients with PAVMs.

Venous Sac and Feeding Artery Embolization versus Feeding Artery Embolization Alone for Treating Pulmonary Arteriovenous Malformations: Draining Vein Size Outcomes

PURPOSE

To investigate and compare venous sac and feeding artery embolization (VFE) with feeding artery embolization (FAE) alone for treatment of pulmonary arteriovenous malformations (PAVMs), based on difference in outcomes in decrease of the size of the draining vein.

MATERIALS AND METHODS

Twenty-six patients (7 male and 19 female; median age [interquartile range], 58 years [46-65 years]) with 42 simple PAVMs treated with coil embolization between August 2005 and December 2018 were retrospectively evaluated. Twenty PAVMs were treated with FAE early in the study period and compared with 22 PAVMs treated with VFE later in the study period. Follow-up computed tomography images obtained 8-20 months after embolotherapy were used for outcome analysis. Data related to patient demographics; follow-up period; baseline diameters of the feeding artery, venous sac, and draining vein; draining vein diameter after treatment; and decrease in the size of the draining vein, including the number reaching a threshold of 70% decrease, were compared between the 2 groups.

RESULTS

The draining vein decreased in size by a median of 46.4% in the FAE group and 66.3% in the VFE group, and the difference between the 2 groups was statistically significant (P = .009). There were no significant differences in the other parameters.

CONCLUSIONS

VFE leads to a greater decrease in the size of the draining vein than FAE, suggesting that VFE results in more complete occlusion than FAE for treatment of PAVMs.

Safety of Catheter Embolization of Pulmonary Arteriovenous Malformations-Evaluation of Possible Cerebrovascular Embolism after Catheter Embolization of Pulmonary Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia/Osler Disease by Pre- and Post-Interventional DWI

Background. This paper aimed to prospectively evaluate the safety of embolization therapy of pulmonary arteriovenous malformations (PAVMs) for the detection of cerebral infarctions by pre- and post-interventional MRI. Method One hundred and five patients (male/female = 44/61; mean age 48.6+/−15.8; range 5–86) with pre-diagnosed PAVMs on contrast-enhanced MRA underwent embolization therapy. The number of PAVMs treated in each patient ranged from 1–8 PAVMs. Depending on the size and localization of the feeding arteries, either Nester-Coils or Amplatzer vascular plugs were used for embolization therapy. cMRI was performed immediately before, and at the 4 h and 3-month post-embolization therapy. Detection of peri-interventional cerebral emboli was performed via T2w and DWI sequences using three different b-values, with calculation of ADC maps. Results Embolization did not show any post-/peri-interventional, newly developed ischemic lesions in the brain. Only one patient who underwent re-embolization and was previously treated with tungsten coils that corroded over time showed newly developed, small, diffuse emboli in the post-interventional DWI sequence. This patient already had several episodes of brain emboli before re-treatment due to the corroded coils, and during treatment, when passing the corroded coils, experienced additional small, clinically inconspicuous brain emboli. However, this complication was anticipated but accepted, since the vessel had to be occluded distally. Conclusion Catheter-based embolization of PAVMs is a safe method for treatment and does not result in clinically inconspicuous cerebral ischemia, which was not demonstrated previously.

Pulmonary arteriovenous malformation (PAVM) embolization: prediction of angiographically-confirmed recanalization according to PAVM Diameter changes on CT

Background

To assess pulmonary arteriovenous malformation (PAVM) recanalization after embolization based on PAVM diameter changes on computed tomography (CT), with pulmonary angiography used as a gold standard.

Methods

A retrospective review was done of patients from 2008 to 2019 with a PAVM treated with endovascular embolization. The treatment outcome was determined by conventional angiography. Follow-up pulmonary angiography was performed when recanalization was suspected on CT, or embolization of all lesions in multiple PAVM patients could not be completed in a single session. Patients who had no preprocedural or follow-up CT were excluded. Draining vein, feeding artery, and venous sac diameter were measured on CT, and diameter reduction rates were compared with the widely-used, binary 70 % criteria.

Results

Forty-one patients with 114 PAVMs were treated during the study period. Eight patients with 50 PAVMs met the inclusion criteria. Mean vein, artery, and venous sac diameter reduction rates were as follows: 59.2 ± 9.3 %, 47.5 ± 10.6 %, and 62.6 ± 13.2 %, respectively, in the occluded group and 5.4 ± 19.5 %, 11.3 ± 17.7 %, and 26.8 ± 14.2 %, respectively, in the recanalized group. The area under the receiver operating characteristic curves for PAVM recanalization for the draining vein was 1.00, showing a better result than the artery (0.97) and sac (0.99). Patients showed > 42 % draining vein diameter reduction in the occluded group and < 32 % in the recanalized group. The widely-used 70 % criteria showed low specificity for predicting recanalization (draining vein, 7.3 %; venous sac, 41.7 %) but 100 % sensitivity for both the draining vein and venous sac.

Conclusions

The widely-used 70 % binary criteria showed limited performance in predicting outcomes in this angiographically-confirmed case series. Further investigations are warranted to establish a strategy for detecting recanalization after PAVM embolization.

Location of embolization affects patency after coil embolization for pulmonary arteriovenous malformations: importance of time-resolved magnetic resonance angiography for diagnosis of patency

OBJECTIVES

This study aimed to assess the diagnostic accuracy of computed tomography (CT) and time-resolved magnetic resonance angiography (TR-MRA) for patency after coil embolization of pulmonary arteriovenous malformations (PAVMs) and identify factors affecting patency.

METHODS

Data from the records of 205 patients with 378 untreated PAVMs were retrospectively analyzed. Differences in proportional reduction of the sac or draining vein on CT between occluded and patent PAVMs were examined, and receiver operating characteristic analysis was performed to assess the accuracy of CT using digital subtraction angiography (DSA) as the definitive diagnostic modality. The accuracy of TR-MRA was also assessed in comparison to DSA. Potential factors affecting patency, including sex, age, number of PAVMs, location of PAVMs, type of PAVM, and location of embolization, were evaluated.

RESULTS

The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT were 82%, 81%, 77%, 85%, and 82%, respectively, when the reduction rate threshold was set to 55%, which led to the highest diagnostic accuracy. The sensitivity, specificity, PPV, NPV, and accuracy of TR-MRA were 89%, 95%, 89%, 95%, and 93%, respectively. On both univariable and multivariable analyses, embolization of the distal position to the last normal branch of the pulmonary artery was a factor that significantly affected the prevention of patency.

CONCLUSIONS

TR-MRA appears to be an appropriate method for follow-up examinations due to its high accuracy for the diagnosis of patency after coil embolization of PAVMs. The location of embolization is a factor affecting patency.

KEY POINTS

• Diagnosis of patency after coil embolization for pulmonary arteriovenous malformations (PAVMs) is important because a patent PAVM can lead to neurologic complications. • The diagnostic accuracies of CT with a cutoff value of 55% and TR-MRA were 82% and 93%, respectively. • The positioning of the coils relative to the sac and the last normal branch of the artery was significant for preventing PAVM patency.

Comparison of Contrast Enhanced Magnetic Resonance Angiography to Computed Tomography in Detecting Pulmonary Arteriovenous Malformations

Background: Computed tomography (CT) is considered the imaging modality of choice to diagnose pulmonary arteriovenous malformations PAVMs. The drawback of this technique is that it requires ionizing radiation. Magnetic resonance (MR) imaging does not have the limitation, but little is known about the performance of MR compared to CT for the detection of PAVMs. The aim of this study is to investigate the sensitivity of contrast-enhanced MR angiography (CE-MRA) in the detection of PAVMs with feeding artery diameters (FAD) > 2 mm. Methods: Patients with a grade 2 or 3 shunt on screening transthoracic contrast echocardiography (TTCE) were asked to participate. Included patients underwent chest CT and CE-MRA. CT was considered the reference standard. CT and CE-MRA scans were anonymized and assessed for the presence of PAVMs with FAD > 2 mm by one and two readers respectively. Data analysis was performed on per patient and per PAVM basis. Results: Fifty-three patients were included. 105 PAVMs were detected on CT, 45 with a FAD ≥ 2 mm. In per patient analysis, sensitivity and specificity of CE-MRA were 92% and 97% respectively for reader 1 and 92% and 62% for reader 2. Negative and positive predictive value (NPV/PPV) were 93% and 96% for R1 and 90% and 67% for R2. In per PAVM analysis, sensitivity, specificity, NPV and PPV were 96%, 99%, 100% and 86% for R1 and 93%, 96%, 100% and 56% for R2, respectively. Conclusions: CE-MRA has excellent sensitivity and NPV for detection of PAVMs with FAD ≥ 2 mm and can therefore be used to detect these PAVMs. We are hopeful that future advancements in CE-MRA technology will reduce false positive rates and allow for more broad use of CE-MRA in PAVM diagnosis and management.

Approach to Pulmonary Arteriovenous Malformations: A Comprehensive Update

Pulmonary arteriovenous malformations (PAVMs) are abnormal direct vascular communications between pulmonary arteries and veins which create high-flow right-to-left shunts. They are most frequently congenital, usually in the setting of hereditary hemorrhagic telangiectasia (HHT). PAVMs may be asymptomatic or present with a wide variety of clinical manifestations such as dyspnea, hypoxemia, or chest pain. Even when asymptomatic, presence of PAVMs increases patients' risk of serious, potentially preventable complications including stroke or brain abscess. Transcatheter embolotherapy is considered the gold standard for treatment of PAVMs. Though previous guidelines have been published regarding the management of PAVMs, several aspects of PAVM screening and management remain debated among the experts, suggesting the need for thorough reexamination of the current literature. The authors of this review present an updated approach to the diagnostic workup and management of PAVMs, with an emphasis on areas of controversy, based on the latest literature and our institutional experience.

Successful occlusion of a large pulmonary arterio-venous fistula with Amplatzer septal occluder in a 16-year-old cyanotic boy

Pulmonary arterio-venous fistula is an uncommon cause of cyanosis and should be suspected when normal cardiac examination is associated without evidence of intra-cardiac shunt. Diagnosis of extra-cardiac shunt can be suspected by contrast echocardiography using agitated saline and confirmation of pulmonary arterio-venous fistula can be made by computed tomography pulmonary angiography with information regarding the size feeding vessels necessary for the planning of intervention. With the advancement of trans-catheter devices, fistula can be occluded successfully by embolotherapy. Coils, duct occluders, and vascular plugs are some of the commonly used trans-catheter devices among the armamentarium. Each device has its own inherent advantages and limitations. However, operators' familiarity and expertise is an important parameter to choose the device to be employed in closure of fistula. The experience of Amplatzer family of devices in closure of pulmonary arterio-venous fistula is limited in the literature. We report a case of large pulmonary arterio-venous fistula successfully closed with a 20 mm Amplatzer septal occluder device in a 16-year-old cyanotic boy. Post-procedure contrast echocardiography confirmed absence of right to left shunt and computed tomography pulmonary angiography confirmed the device in situ closing the feeding vessel. Over a follow-up of six months reversal of clubbing and cyanosis was noted. <Learning objective: Patients with cyanosis with normal cardiac examination without evident intra-cardiac shunt in echocardiography should be evaluated for pulmonary arterio-venous fistula. Computed tomography Pulmonary angiography is gold standard but contrast echocardiography can be valuable. Percutaneous trans-catheter closure using coils, duct occluders, or vascular plugs can be an alternative to surgery. Choice of device depends on size and tortuosity of the feeding vessel as well as operator's familiarity with the device.>.

Treatment of pulmonary arteriovenous malformations: clinical experience using different embolization strategies

PURPOSE

To evaluate embolization efficacy of pulmonary arteriovenous malformations (PAVM) using Amplatzer vascular plugs (AVP) and coils.

MATERIALS AND METHODS

Eighty-eight embolized simple PAVMs in 38 patients were retrospectively analyzed by follow-up CT. Mean age was 50.2 ± 15.6 years and 22 (57.9%) patients were females. Mean follow-up interval was 38.2 ± 28.4 months (median 29.9 months). Embolization devices included AVP I, AVP II, AVP 4, and coils. Technical success was defined as no visualization of an early draining vein at angiography after embolization. Treatment success was defined as complete disappearance or decrease in size of the venous aneurysm ≥ 70% at follow-up CT.

RESULTS

Technical success rate was 100% and treatment success rate evaluated by CT for the various embolization strategies was 100% for AVP I (n = 6), 100% for AVP I + coils (n = 5), 83.3% for AVP II (n = 6), 40.0% for AVP II + coils (n = 5), 87.5% for AVP 4 (n = 8), 50.0% for AVP 4 + coils (n = 8), and 78.0% for coils alone (n = 50). No statistically significant difference in embolization efficacy was seen between different devices (P = 0.083). Although not statistically significant, combination use of coils with AVPs demonstrated lower rates of clinical embolization success (P = 0.053).

CONCLUSION

Embolization of PAVMs demonstrated high technical and treatment success rates with available embolic devices. No significant statistical differences were demonstrated between AVPs. However, the need for both coils and AVPs may suggest a more complicated underlying lesion at risk for recurrence.

Embolisation of pulmonary arteriovenous malformations using high-frequency jet ventilation: benefits of minimising respiratory motion

Background

To evaluate patient radiation dose and procedural duration recorded during pulmonary arteriovenous malformation (PAVM) embolisation performed using high-frequency jet ventilation (HFJV) as compared with conventional intermittent positive pressure ventilation (IPPV)

Methods

Patients undergoing PAVM embolisation with HFJV assistance after April 2017 were retrospectively identified as group A, and those treated with IPPV before April 2017 as group B. Primary outcomes were patient radiation dose and procedural duration between groups A and B. Secondary outcomes were difference in diaphragmatic excursion between groups A and B, in group A with/without HFJ assistance, technical/clinical success, and complications.

Results

Twelve PAVMs were embolised in 5 patients from group A, and 15 PAVMs in 10 patients from group B. Mean patient radiation was significantly lower in group A than in group B (54,307 ± 33,823 mGy cm² [mean ± standard deviation] versus 100,704 ± 43,930 mGy cm²; p = 0.022). Procedural duration was 33.4 ± 16.1 min in group A versus 57.4 ± 14.9 min in group B (p = 0.062). Diaphragmatic excursion was significantly lower in group A (1.3 ± 0.4 mm) than in group B (19.7 ± 5.2 mm; p < 0.001) and lower with near statistical significance in group A with HFJV than without HFJV (1.3 ± 0.4 mm versus 10.9 ± 3.1 mm; p = 0.062). Technical and clinical success was 100% in both groups, without relevant complications.

Conclusion

HFJV-assisted PAVM embolisation is a safe, feasible technique resulting in reduced patient radiation doses and procedural time.

Retrospective Comparison of Pulmonary Arteriovenous Malformation Embolization with the Polytetrafluoroethylene-Covered Nitinol Microvascular Plug, AMPLATZER Plug, and Coils in Patients with Hereditary Hemorrhagic Telangiectasia

PURPOSE

To evaluate effectiveness of the polytetrafluoroethylene-covered nitinol mesh microvascular plug (MVP) and compare it with other devices in pulmonary arteriovenous malformation (PAVM) embolization in patients with hereditary hemorrhagic telangiectasia (HHT).

MATERIALS AND METHODS

Twenty-five patients (average age 35 y; range, 15-56 y) with hereditary hemorrhagic telangiectasia (HHT) and de novo PAVM embolization with at least 1 MVP between November 2015 and May 2017 were retrospectively evaluated. Retrospective data were also obtained from prior embolization procedures in the same patient population with other embolic devices dating back to 2008. Technical success, complications, PAVM persistence rates, and category of persistence were analyzed.

RESULTS

In 25 patients, 157 PAVMs were treated: 92 with MVP, 35 with AMPLATZER vascular plug (AVP), 6 with AVP plus coils, and 24 with coils. The per-PAVM technical success rates were 100% with MVP; 97%, AVP; 100%, AVP plus coils; and 100%, coils. PAVM persistence rates and median follow-up were as follows: MVP, 2% (1/92) (510 d); AVP, 15% (3/20) (1,447 d); AVP plus coils, 20% (1/5) (1,141 d); coils, 46.7% (7/15) (1,141 d). Persistence owing to recanalization for MVP, AVP, AVP plus coils, and coils was 2%, 15%, 0%, and 33%. No difference was found between persistence rates of MVP vs AVP (P = .098). Embolization with a vascular plug (MVP or AVP) with or without coils had a statistically significant lower persistence rate (5.4%) than embolization with coils alone (46.7%) (P = .022).

CONCLUSIONS

PAVM embolization with MVP had a high technical success rate and a low persistence rate comparable to AVP and lower than coil embolization alone.

Patients with in-situ metallic coils and Amplatzer vascular plugs used to treat pulmonary arteriovenous malformations since 1984 can safely undergo magnetic resonance imaging

Objective:

To examine the MRI safety of metallic coils and Amplatzer vascular plugs. Currently, concern regarding MR safety of devices used to treat pulmonary arteriovenous malformations (PAVMs) causes delays in performing emergency MRI in patients presenting with acute neurological symptoms.

Methods:

A retrospective audit was performed on all patients who underwent PAVM embolization at Hammersmith Hospital, London UK between 1984 and 2017. Outcomes of all MRI studies performed at our institution were recorded. In addition, known outcomes of all known MRI studies performed on patients treated with the earliest steel coils (1984–1995) were recorded.

Results:

At our institution, 20 patients underwent 1.5 T MRI after the insertion of 100 steel coils (15.5 – 28.6, median 22 years later), 140 coils designated MR-conditional (0.42 – 12.7, median 9.3 years later), and 54 MRI-conditional Amplatzer vascular plugs (0.17 – 8.0, median 0.75 years later), many in combination. The majority of scans were for cerebral indications, but other body regions scanned included spinal, thoracic, and pelvic regions. No adverse events were reported. Similarly, there were no adverse events in any MR scan known to have been performed in other institutions in seven further patients treated with the earliest steel coils (1984–1995). Again, the majority of scans were for cerebral indications.

Conclusion:

The findings demonstrate MR safety at 1.5 T of all PAVM embolization devices inserted in a main UK centre since inception in 1984.

Advances in knowledge:

MRI of patients who have had PAVMs treated by embolization can be implemented without contacting specialist pulmonary arteriovenous malformation treatment centres for approval.

Efficacy and Safety of AMPLATZER Vascular Plug Type IV for Embolization of Pulmonary Arteriovenous Malformations

PURPOSE

To assess the efficacy and safety of the AMPLATZER Vascular Plug type IV for pulmonary arteriovenous malformation (PAVM) treatment.

MATERIALS AND METHODS

Between June 2013 and January 2018, 13 patients with 26 PAVMs were treated with the type IV AVP. Patients without follow-up computed tomography (CT) were excluded. Technical success was defined as flow occlusion on angiography. Plug-to-sac distance was measured on angiographic images. Feeding artery and venous sac diameter changes were measured on preprocedural and follow-up CT. Successful embolization was defined as > 70% sac size regression. Procedure time, device migration, and complications were evaluated.

RESULTS

Nine female patients (mean age, 49 y; range, 40-71 y) with 19 PAVMs were enrolled. Four patients with 7 PAVMs were lost to follow-up. Nineteen PAVMs were treated in 11 sessions, and the mean procedure time was 29 min. The technical success rate was 100%. Mean feeding artery diameter was 3.1 mm ± 0.7 (range, 2.1-4.9 mm). Mean plug-to-sac distance was 5.4 mm ± 4.9 (range, 0-13.3 mm). The mean CT follow-up period was 14 months ± 7 (range, 6-30 mo). Sixteen of 19 PAVMs (84%) were successfully embolized. Minor complications (tachycardia and chest discomfort) arose in 2 of 11 sessions. No device migrations or major complications occurred.

CONCLUSIONS

The type IV AVP showed an 84% treatment success rate based on 70% sac size regression criteria in small PAVMs. There were no device migrations or major complications.

MVP™ Micro Vascular Plug Systems for the Treatment of Pulmonary Arteriovenous Malformations

PURPOSE

To describe our institutional experience with MVP™ micro vascular plug systems for the treatment of pulmonary arteriovenous malformations (PAVMs).

MATERIALS AND METHODS

We performed a retrospective medical record review of 52 patients with 119 PAVMs treated exclusively with MVP™ systems (69 procedures/153 MVP™ systems) between July 2014 and July 2018. All patients had PAVMs with feeding artery diameters ≥ 2 mm. MVP™ systems were deployed according to physician preference. We collected patient demographic information; procedural data (including size of feeding artery, size and number of embolics used per PAVM, fluoroscopy time, contrast administration), technical success rates, complications, and persistence. Persistence was assessed using computed tomography angiography (CTA) performed 1-3 months and 3-5 years after embolization per clinical protocol.

RESULTS

All procedures were technically successful without major complications. Mean feeding artery diameter was 3.3 ± 1.2 mm. Mean fluoroscopy time per procedure and contrast volume administered per procedure were 35 ± 16 min and 217 ± 101 mL, respectively. A mean of 1.3 ± 0.8 MVP™ systems was used per PAVM. There were no instances of persistence during a mean follow-up time of 328 ± 258 days (range 26 to 914 days).

CONCLUSIONS

For PAVMs with feeding artery diameters of 2 to 7.9 mm (mean 3.3 ± 1.2 mm), MVP™ systems are safe and effective given their high technical success rates and lack of persistence. Further prospective work will be required to elucidate the advantages and disadvantages of these MVP™ systems for PAVM embolization.

LEVEL OF EVIDENCE

Level III.

Where is the Origin of the Last Normal Branch from Feeding Artery of Pulmonary Arteriovenous Malformations?

Purpose

Reperfusion via pulmonary-to-pulmonary arterial anastomoses is known as one type of recurrence of pulmonary arteriovenous malformations (PAVMs) after embolization. It is important to occlude the fistulous portion beyond the origin of the last normal branch from feeding artery of PAVMs to prevent recurrence. In this study, we evaluate the origin of the last normal branch by CT as well as its visibility on pulmonary arteriography (PAG).

Materials and Methods

We reviewed forty patients with 77 PAVMs who underwent coil embolization between October 2007 and December 2017. All patients underwent MDCT before embolization. Axial and MPR CT lung images were reviewed with special interests in the origin of the last normal branch from feeding artery of PAVMs. The origin was classified into three portions, including sac, junction (portion just proximal to the sac) and proximal feeder (more than 5 mm proximal to the sac). We also evaluated whether PAG can depict the normal branches detected by MDCT.

Results

MDCT showed that the last normal branch originated from sac in 30 PAVMs (39.0%), junction in 39 (50.6%), and proximal feeder in 8 (10.4%).On selective PAG, the last normal branch could be visualized in 30 PAVMs (39.0%), although it could not be visualized due to high-flow shunt in the other 47 PAVMs.

Conclusions

Selective PAG frequently fails to demonstrate the last normal branch from feeding artery of PAVMs, which often originates from the sac. Pretherapeutic evaluation of CT images of the last normal branch is important to prevent reperfusion of PAVMs.

Level of Evidence

Level 3, local non-random sample.

Successful treatment of multiple pulmonary arteriovenous fistulae with thoracoscopy

Congenital pulmonary arteriovenous fistulae occur as a result of abnormal blood vessel development in the lungs. Blood takes a short pass from the pulmonary artery to veins. Multiple pulmonary arteriovenous fistulae are a rare occurrence, especially when involving both lungs. Fistulae located at the edge are prone to rupture and bleeding. We discuss a case of a 15‐year‐old overweight male with multiple pulmonary arteriovenous fistulae successfully treated with wedge‐shape excision via video‐assisted thoracoscopic surgery.

Hemoglobin Is a Vital Determinant of Arterial Oxygen Content in Hypoxemic Patients with Pulmonary Arteriovenous Malformations

RATIONALE

Pa_O2 and Sa_O2 are commonly measured in respiratory practice, but arterial oxygen content (Ca_O2) refers to the volume of oxygen delivered to the tissues per unit blood volume. Ca_O2 is calculated from Sa_O2 and the hemoglobin concentration in blood, recognizing that each gram of hemoglobin can transport approximately 1.34 ml of oxygen when fully saturated.

OBJECTIVES

To prospectively evaluate serial changes in Ca_O2 in humans, incorporating and excluding dynamic changes to oxygenation and hemoglobin parameters that may occur during life.

METHODS

A cohort of 497 consecutive patients at risk of both hypoxemia and anemia were recruited. The patients had radiologically proven pulmonary arteriovenous malformations (PAVMs), which result in hypoxemia due to right-to-left shunting, and concurrent hereditary hemorrhagic telangiectasia, which placed them at risk of iron deficiency anemia due to recurrent hemorrhagic iron losses. Presentation Sa_O2 (breathing room air, by pulse oximetry), hemoglobin, red cell and iron indices were measured, and Ca_O2 calculated as Sa_O2 × hemoglobin × 1.34 ml/g. Serial measurements were evaluated in 100 cases spanning up to 32.1 (median, 10.5) years.

RESULTS

Presentation Ca_O2 ranged from 7.6 to 27.5 (median, 17.6) ml/dl. Ca_O2 did not change appreciably across the Sa_O2 quartiles. In contrast, hemoglobin ranged from 5.9 to 21.8 g/dl (median, 14.1 g/dl), with a linear increase in Ca_O2 across hemoglobin quartiles. After PAVM embolization and an immediate increase in Sa_O2, hemoglobin fell and Ca_O2 was unchanged 1.6-12 (median, 4) months later. When hemoglobin fell because of iron deficiency, there was no change in Sa_O2. Similarly, when hemoglobin rose after iron treatment, there was no change in Sa_O2, and the expected Ca_O2 increment was observed. These relationships were not evident during pregnancy when hemoglobin fell, and PAVMs usually deteriorated: in pregnancy Sa_O2 commonly increased, and serial Ca_O2 values (incorporating hemodilution/anemia) more accurately reflected deteriorating PAVM status. An apparent fall in Ca_O2 with age in females was attributable to the development of iron deficiency. There was an unexplained increase in Ca_O2 with age in follow-up of males after embolization.

CONCLUSIONS

Hemoglobin/Ca_O2 should be further incorporated into oxygenation considerations. More attention should be given to modest changes in hemoglobin that substantially modify Ca_O2.

Usefulness of Hydrogel-Coated Coils in Embolization of Pulmonary Arteriovenous Malformations

Purpose

To evaluate the usefulness of hydrogel-coated coils for preventing recanalization after coil embolization of pulmonary arteriovenous malformations (PAVMs).

Materials and Methods

Thirty-seven consecutive patients with 57 untreated PAVMs underwent coil embolization with hydrogel-coated coils between January 2013 and Jun 2017. The mean age was 49 years (range 9–83 years), and there were seven male patients and 30 female patients. The median size of the feeding artery was 3.7 mm (range 1.5–6.1 mm), and the median size of the venous sac was 9.3 mm (range 2.6–36.6 mm). For all PAVM, embolization was attempted using 0.018-in. hydrogel-coated coils with or without other coils (0.0135–0.018-in. bare platinum coils and fibered platinum coils). Technical success rate, recanalization rate, and complications were evaluated. Technical success was defined as completion of embolization using hydrogel-coated coils. Recanalization was evaluated with time-resolved magnetic resonance angiography and/or pulmonary angiography.

Results

In 56 of 57 PAVMs, embolization was successfully performed with hydrogel-coated coils. Therefore, the technical success rate was 98% (56/57). The number of PAVMs at risk was 56, 42, 18, and 12 at 0, 12, 24, and 36 months, respectively. There was no recanalization with a mean follow-up period of 19 months (range 2–47 months) in 56 PAVMs embolized with hydrogel-coated coils. There were no major complications. As a minor complication, local pain was observed in 8 of 43 sessions (19%) after embolization.

Conclusions

Hydrogel-coated coils may be useful for preventing recanalization after the embolization of PAVMs.

Long-term outcomes of patients with pulmonary arteriovenous malformations considered for lung transplantation, compared with similarly hypoxaemic cohorts

INTRODUCTION

Pulmonary arteriovenous malformations (PAVMs) may not be amenable to treatment by embolisation or surgical resection, and many patients are left with significant hypoxaemia. Lung transplantation has been undertaken. There is no guidance on selection criteria.

METHODS

To guide transplantation listing assessments, the outcomes of the six patients who had been considered for transplantation were compared with a similarly hypoxaemic patient group recruited prospectively between 2005 and 2016 at the same UK institution.

RESULTS

Six patients had been formally considered for lung transplantation purely for PAVMs. One underwent a single lung transplantation for diffuse PAVMs and died within 4 weeks of surgery. The other five were not transplanted, in four cases at the patients' request. Their current survival ranges from 16 to 27 (median 21) years post-transplant assessment. Of 444 consecutive patients with PAVMs recruited between 2005 and 2016, 42 were similarly hypoxaemic to the 'transplant-considered' cohort (SaO2 <86.5%). Hypoxaemic cohorts maintained arterial oxygen content (CaO2) through secondary erythrocytosis and higher haemoglobin. The 'transplant-considered' cohort had similar CaO2 to the hypoxaemic comparator group, but higher Medical Research Council (MRC) dyspnoea scores (p=0.023), higher rates of cerebral abscesses (p=0.0043) and higher rates of venous thromboemboli (p=0.0009) that were evident before and after the decision to list for transplantation.

CONCLUSIONS

The non-transplanted patients demonstrated marked longevity. Symptoms and comorbidities were better predictors of health than oxygen measurements. While a case-by-case decision, weighing survival estimates and quality of life will help patients in their decision making, the data suggest a very strong case must be made before lung transplantation is considered.

Pulmonary arteriovenous malformations in hereditary haemorrhagic telangiectasia: Correlations between computed tomography findings and cerebral complications

OBJECTIVES

Computed tomography (CT) is the modality of choice to characterise pulmonary arteriovenous malformations (PAVMs) in patients with hereditary haemorrhagic telangiectasia (HHT). Our objective was to determine if CT findings were associated with frequency of brain abscess and ischaemic stroke.

METHODS

This retrospective study included patients with HHT-related PAVMs. CT results, i.e. PAVM presentation (unique, multiple, disseminated or diffuse), the number of PAVMs and the largest feeding artery size, were correlated to prevalence of ischaemic stroke and brain abscess. All CTs were reviewed in consensus by two radiologists.

RESULTS

Of 170 patients, 73 patients had unique (42.9 %), 49 multiple (28.8 %), 36 disseminated (21.2 %) and 12 diffuse (7.1 %) PAVMs. Fifteen patients presented with brain abscess; 26 patients presented with ischaemic stroke. The number of PAVMs was significantly correlated with brain abscess (11.5 vs. 6.2, respectively; p=0.025). The mean diameter of the largest feeding artery was significantly correlated with ischaemic stroke frequency (4.9 vs. 3.2 mm, respectively; p=0.0098).

CONCLUSIONS

The number of PAVMs correlated significantly with risk of brain abscess, and a larger feeding artery significantly with more ischaemic strokes. These findings can lead to a better recognition and management of the PAVMs at risk of cerebral complications.

KEY POINTS

• Chest CT helps clinicians to facilitate appropriate PAVM management strategies. • Pulmonary arteriovenous malformation CT findings are correlated with risk of cerebral complications. • Risk of brain abscess is significantly correlated with number of PAVMs. • Risk of ischaemic stroke is significantly correlated with large feeding artery PAVMs. • Prevalence of observed of brain abscess and ischaemic stroke is 26 %.

Does the type and size of Amplatzer vascular plug affect the occlusion time of pulmonary arteriovenous malformations?

PURPOSE

Occlusion time (OT) is an important factor in the treatment of pulmonary arteriovenous malformations (PAVMs) since it can lead to serious complications. The purpose of our study is to calculate the OT of Amplatzer vascular plug (AVP, St Jude Medical), and correlate it to the type of the device used (AVP or AVP 2) and the percent of device oversizing. Technical success rates and complications were also recorded.

METHODS

We retrospectively studied a total of 19 patients with 47 PAVMs who received percutaneous transcatheter embolization therapy using either AVP or AVP 2. We recorded the location, type, feeding artery diameter, AVP device used, and OT of each PAVM. We correlated the percent of device oversizing and the type of AVP with the OT. We also studied the rate of persistence of PAVM for both devices.

RESULTS

Forty-six (98%) of the PAVMs were simple. Device diameters ranged from 4.0-16.0 mm with device oversizing ranging between 14% and 120%. There was a statistically significant difference in the OT of AVP and AVP 2 (3 min 54 s vs. 5 min 30 s, P = 0.030). There was a weak positive correlation between OT and device oversizing for AVP (r=0.246, P = 0.324) and AVP 2 (r=0.261, P = 0.240). No major complications were identified. Immediate technical success rate was 100%.

CONCLUSION

The use of AVP 2, and increase in device oversizing were not associated with reduction in the OT of PAVMs. There was no reported difference in safety between the two devices, and no major complications were noted.

Persistence of pulmonary arteriovenous malformations after successful embolotherapy with Amplatzer vascular plug: long-term results

PURPOSE

We aimed to evaluate the frequency of persistence and complication rates of pulmonary arteriovenous malformations (PAVMs) treated with Amplatzer vascular plug (AVP) or Amplatzer vascular plug type 2 (AVP2).

METHODS

We retrospectively reviewed a total of 22 patients with 54 PAVMs between June 2004 and June 2014. We included 12 patients with 35 PAVMs who received percutaneous embolization using AVP or AVP2 only without the use of any other embolic devices. The mean follow-up was 54±24.3 months (range, 31-97 months). The primary end-points of the study were the efficacy of embolotherapy, the increase in oxygen saturation, and the persistence of PAVM on follow-up. Secondary end point was the incidence of complications.

RESULTS

The study included 10 female and two male patients with a mean age of 50.2±13.7 years (range, 21-66 years). All PAVMs had a simple angioarchitecture. The technical success of the procedure for PAVM occlusion was 100%. There was a significant increase in the oxygen saturation following embolotherapy (P < 0.0001). Follow-up computed tomography angiography revealed successful treatment in 34 PAVMs (97%) and failed treatment in one PAVM (3%). Twenty-three aneurysmal sacs (67%) showed complete disappearance. The failed treatment was due to persistence of PAVM caused by subsequent development of systemic reperfusion, which did not require further intervention. There were two minor complications but no major complications were encountered.

CONCLUSION

Embolotherapy of PAVMs using AVP or AVP2 devices is safe and effective, with high technical success rate, low persistence and complication rates, and with excellent long-term results.

Pulmonary Arteriovenous Malformation Causing Systemic Hypoxemia in Early Infancy

Pulmonary arteriovenous malformation (AVM) is not routinely appreciated during the standard echocardiogram to assess for structural abnormalities or pulmonary hypertension. The distal pulmonary AVM is suspected only if an injection of agitated saline is performed and late entry of particles is appreciated in the left heart structures. A large or complex pulmonary AVM can result in significant right-to-left shunting and consequential systemic hypoxemia in the presence or absence of pulmonary hypertension. For direct visualization of the pulmonary AVM, computerized tomography (CT) scan is the procedure of choice. Here, we present two young infants with systemic hypoxemia who underwent standard medical management including mechanical ventilation and one patient was placed on extracorporeal membrane oxygenation (ECMO) before the diagnosis of pulmonary AVM was established. Subsequently, both patients have done well into mid-term follow-up after being treated successfully using transcatheter occlusion techniques in the cardiac catheterization laboratory during early infancy. We aim to emphasize the importance of a high index of suspicion for pulmonary AVM in infants with refractory systemic hypoxemia of unclear etiology.

Comparison of Vascular Plugs and Pushable Coils for Variceal Embolization After TIPS

OBJECTIVE

Transjugular intrahepatic portosystemic shunt (TIPS) with variceal embolization is routinely performed to treat variceal bleeding. Embolization using vascular plugs is reported, but outcomes are not known. Outcomes and material costs of embolization using vascular plugs and coils are compared.

MATERIALS AND METHODS

A single center's medical records of TIPS procedures (May 2003-December 2014) with variceal embolization were reviewed. Twenty patients with vascular plug embolization (age [± SD], 50 ± 10 years; seven men and 13 women; median Model for End-Stage Liver Disease [MELD], 20; interquartile range [IQR], 14-23) were compared with an age-, sex-, and MELD-matched cohort who underwent coil embolization (age, 50 ± 9 years; seven men and 13 women; median MELD, 17; IQR, 15-19; p = 0.52). Procedure details, primary outcome (rebleeding), secondary outcome (mortality), and costs were compared.

RESULTS

Vascular plug use was associated with a lower fluoroscopy time (49.05 minutes [IQR, 36-62] vs 68 minutes [IQR, 49-76]; p = 0.006) and total procedure time (255 minutes [IQR, 205-290] for vascular plugs vs 275 minutes [IQR, 230-330]; p = 0.05). Total volume of contrast agent used was similar (180 mL [IQR, 155-234] for vascular plugs vs 210 mL [IQR, 185-261]; p = 0.14). In patients with at least a 30-day follow-up, rebleeding rates (2/17 [12%] for vascular plugs vs 4/15 [27%]; p = 0.40) and mortality (2/17 [12%] for vascular plugs vs 4/15 [27%]; p = 0.66) were similar. Per procedure, vascular plugs cost significantly more than coils ($1292 ± $676 vs $228 ± $292, p < 0.0001).

CONCLUSION

The use of vascular plugs or coils has similar outcomes for variceal embolization after TIPS. The advantages of vascular plug use (i.e., reduced fluoroscopy or procedure time) may be offset by increased material cost, a trade-off that merits further study given current cost concerns in health care.

Preliminary Experience with Vascular Plugs for Parent Artery Occlusion of the Carotid or Vertebral Arteries

OBJECTIVE

The purpose of this study was to report the authors' preliminary experience using the Amplatzer Vascular Plug (AVP) (St. Jude Medical, Plymouth, MN, USA) for parent artery occlusion of the internal carotid artery (ICA) or vertebral artery (VA).

MATERIALS AND METHODS

Between September 2008 and December 2015, we performed 52 therapeutic parent artery occlusions (PAOs) by an endovascular technique. Among them, 10 patients underwent PAO of the carotid or vertebral arteries using AVPs. Clinical and radiographic data of these patients were retrospectively reviewed.

RESULTS

The devices were used for VA dissection that presented with subarachnoid hemorrhage (SAH) in five patients, traumatic arteriovenous fistula (AVF) in two patients, spontaneous AVF in one patient, recurrence of carotid-cavernous fistula (CCF) in one patient, and symptomatic unruptured giant ICA aneurysm in one patient. The devices were used in conjunction with detachable and/or pushable coils and in the extracranial segments of the ICA or VA. Complete occlusion of the parent artery was achieved in all patients. There was one intra-procedural rupture of the VA dissection during coiling prior to using the device.

CONCLUSION

Results from the current series suggest that the AVP might be used for therapeutic PAO in the extracranial segments of the ICA or VA.

Pulmonary Arteriovenous Malformations Embolized Using a Micro Vascular Plug System: Technical Note on a Preliminary Experience

AIM

To report our preliminary experience using a Micro Vascular Plug (MVP) deployed through a 2.8Fr micro-catheter for the treatment of pulmonary arteriovenous malformations (PAVMs) in a cohort of patients affected by Hereditary Haemorrhagic Telangiectasia (HHT).

MATERIALS AND METHODS

Four consecutive female patients (mean age 38.0 years; range 25-55 years) with PAVMs diagnosed on echocardiogram/bubble test and contrast-enhanced CT (CECT) underwent MVP embolization. One patient was symptomatic with recent transient ischaemic attack. Follow-up was undertaken at 1-month post-procedure with CECT to assess PAVMs permeability and MVP positioning and at 1-, 6-, and 12-month post-procedure, with echocardiography/bubble test and standard neurological history, to confirm absence of right-to-left shunts and recurrent symptoms.

RESULTS

Eight PAVMs were treated in 4 patients over 5 interventional sessions (mean 1.6 PAVMs per session). All PAVMs were simple, with mean feeding artery diameter of 4.25 mm. Eight 6.5 mm MVPs were deployed in total (one per lesion). Technical success was 100%. Mean procedural time and patient dose per session were 70 min (range 40-70 min) and 53418 mGy.cm² (range 6113-101628 mGy.cm²), respectively. No signs of reperfusion neither of MPV migration were noted at 1-month CECT follow-up. At early follow-up (mean 3.75 months; range 1-12 months), clinical success was 100% with no evidence of recurrent right-to-left shunt, and no neurological symptoms. No immediate or late complications were observed.

CONCLUSIONS

MVP embolization of PAVMs appears technically feasible, safe, and effective at early follow-up. Further prospective studies are required to confirm long-term safety and efficacy of this promising technique.

Idiopathic pulmonary malformation: A case report

Background:

Pulmonary arteriovenous malformations have been associated with clinical situations that put life at risk or cause physical disability. When the clinical picture is evident, percutaneous occlusion is recommended.

Methods:

We describe the use of an Amplatzer vascular plug in a female patient for the treatment of an idiopathic pulmonary arteriovenous malformation associated with syncope and transient ischemic attacks.

Results:

The patient was successfully treated via percutaneous intervention without complications. At 6 months follow-up, there was an absence of the pulmonary arteriovenous malformation confirmed via angiotomography and a full reintegration into her daily activities with no-clinical eventualities.

Conclusion:

The use of an Amplatzer vascular plug should be considered for the treatment of idiopathic pulmonary arteriovenous malformation. In experienced centers the procedure can be done safely with excellent clinical outcomes.

The diagnosis and interventional management of pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations (PAVM) describe a broad group of complex vascular malformations, often associated with multi-system diseases and with palliated complex congenital heart disease. They can have major clinical consequences, resulting in strokes, cerebral abscesses, cyanosis and, infrequently, rupture into the pleural space. The best approach to their investigation and interventional treatment is via a multidisciplinary pathway which should be focused in high-volume centres with on-site thoracic and cardiovascular surgical back-up. The availability of computed tomography (CT) and a broad cathlab inventory aid procedural planning and success. The results of interventional treatment are very encouraging and are applicable to an increasingly broad group of patients thanks to improvements in interventional techniques and a significant expansion of the inventory of vascular occlusion devices.

The Amplatzer Vascular Plug: Review of Evolution and Current Applications

The Amplatzer Vascular Plug (AVP) was created for peripheral embolization as a modification of the family of Amplatz septal occluders used in the treatment of congenital heart malformations. The device has evolved over the years and multiple versions have been launched into the market. Each of the versions of the device has some important modifications in terms of the size of the introducer's system, number of layers, and resultant thrombogenicity. It is very important for the operator to become familiar with the unique features of the AVP, and to understand the advantages and limitations of each model in the AVP family to achieve an optimal embolic result. The purpose of this article is to review the evolution and current clinical applications of the AVP in the field of interventional radiology, with emphasis on the advantages and limitations of this device in comparison with other embolization agents.

Imaging features and transcatheter treatment of a giant pulmonary arteriovenous malformation in an elderly patient

Pulmonary arteriovenous malformations (PAVMs) comprise an anomalous communication between the pulmonary arterial and systemic circulation. The drainage is usually into one of the pulmonary veins, although rare instances of direct drainage into the left atrium or inferior vena cava have been reported. The result is a high-flow, low-resistance, right-toleft shunt. Although considered uncommon, PAVMs are being diagnosed with increasing frequency in this era of enhanced cross-sectional imaging with CT for lung screening. There is a strong association between PAVMs and hereditary haemorrhagic telangiectasia (HHT); PAVMs are more commonly found in females, with a female to male ratio of 8:1. These have varying clinical presentation, with most symptomatic PAVMs being diagnosed in the first three decades of life. The most common mode of presentation is dyspnoea on exertion. Other reported symptoms are epistaxis, chest pain, cough and, in the event of rupture, haemoptysis. Endocarditis, stroke and brain abscess formation occur frequently in patients with undiagnosed HHT with PAVMs. A 76-year-old female, with a presumed clinical diagnosis of asthma, presented to the emergency department with worsening shortness of breath. The imaging studies revealed a giant PAVM and a radionuclide scan demonstrated a large right-to-left shunt, likely accounting for her symptoms. She underwent successful transcatheter embolization (TCE) with a vascular plug performed by the interventional radiology team. The aim of this case report is to describe the imaging findings and TCE treatment of a giant PAVM.

Radiological Evaluation and Endovascular Treatment of Hemoptysis

Hemoptysis can be a life-threatening condition that warrants urgent investigation and intervention. Common causes include bronchiectasis, chronic obstructive pulmonary disease, tuberculosis, and malignancy. Computed tomography angiography is an accurate imaging modality for assessment of hemoptysis. The bronchial arteries are the source of bleeding in most cases of hemoptysis, and bronchial artery embolization is the treatment of choice. The aim of this article is to summarize the pathophysiology, causes, initial management, and diagnostic approach of hemoptysis. Endovascular treatment of hemoptysis, technique, embolic materials, outcomes, complications, and follow-up of patients are discussed.

Early experience with the AMPLATZER vascular plug IV for the occlusion of pulmonary arteriovenous malformations

The recent generation of AMPLATZER Vascular Plug (AVP; ie, the AVP IV) was used for the occlusion of eight pulmonary arteriovenous malformations (PAVMs) in five patients. A treatment was considered successful when there was a reduction or disappearance of the aneurysmal sac. At a mean follow-up of 20.1 months, no recanalization of PAVMs was observed on multidetector computed tomographic angiography. This shows the AVP IV to be safe and effective as an embolic device to occlude PAVMs.

Pulmonary arteriovenous malformations

Within the past decade, pulmonary arteriovenous malformations (PAVMs) have evolved from rare curiosities to not uncommon clinical states, with the latest estimates suggesting a prevalence of ~1 in 2,600. PAVMs provide anatomic right-to-left shunts, allowing systemic venous blood to bypass gas exchange and pulmonary capillary bed processing. Hypoxemia and enhanced ventilatory demands result, although both are usually asymptomatic. Paradoxical emboli lead to strokes and cerebral abscesses, and these commonly occur in individuals with previously undiagnosed PAVMs. PAVM hemorrhage is rare but is the main cause of maternal death in pregnancy. PAVM occlusion by embolization is the standard of care to reduce these risks. However, recent data demonstrate that currently recommended management protocols can result in levels of radiation exposure that would be classified as harmful. Recent publications also provide a better appreciation of the hematologic and cardiovascular demands required to maintain arterial oxygen content and oxygen consumption in hypoxemic patients, identify patient subgroups at higher risk of complications, and emphasize the proportion of radiologically visible PAVMs too small to treat by embolization. This review, therefore, outlines medical states that exacerbate the consequences of PAVMs. Chief among these is iron deficiency, which is commonly present due to concurrent hereditary hemorrhagic telangiectasia: iron deficiency impairs hypoxemia compensations by restricting erythropoiesis and increases the risk of ischemic strokes. Management of periodontal disease, dental interventions, pulmonary hypertension, and pregnancy also requires specific consideration in the setting of PAVMs. The review concludes by discussing to what extent previously recommended protocols may benefit from modification or revision.

Venous sac embolization of pulmonary arteriovenous malformation: safety and effectiveness at mid-term follow-up

BACKGROUND

The standard technique for the transcatheter treatment of pulmonary arteriovenous malformations (PAVMs) involves deploying coils into the feeding arteries. We investigated whether venous sac embolization would also be a safe and useful treatment method.

PURPOSE

To evaluate the safety and outcomes of venous sac embolization for PAVMs.

MATERIAL AND METHODS

This study included 15 consecutive patients (1 man, 14 women; mean age, 54 years; range, 22-76 years) with 50 PAVMs who underwent 26 procedures; four had a history of earlier cerebral infarction or exertional dyspnea. We first placed 0.018-inch interlocking detachable and/or 0.018-inch or 0.010-inch Guglielmi detachable coils to prevent systemic migration from the venous sac. We then packed the sac as tightly as possible and embolized the orifice at the proximal feeding artery. We used angiographic, clinical, and computed tomography (CT) studies to evaluate the treatment outcomes and safety of these procedures. The mean follow-up was 16 months (range, 3-63 months) in 12 patients with 43 PAVMs; three patients (7 PAVMs) were lost to follow-up.

RESULTS

Immediate post-embolization angiography confirmed complete primary occlusion in 47 of 50 lesions (94%). Minor complications arose in two of 26 procedures (7.7%); they were abnormal electrocardiograms without symptoms during and pleurisy immediately after the procedure. During follow-up, 40 PAVMs were free of CT evidence of reperfusion. The mean partial arterial oxygen pressure increased from 75.3% ± 13.6 before embolization to 85.4% ± 16.3 after embolization (P < 0.01, t-test). Of the 12 patients who were available for follow-up, none experienced new-onset paradoxical embolization; pre-treatment exertional dyspnea was alleviated in one patient. There were no major complications.

CONCLUSION

Venous sac embolization for PAVMs might be safe and more effective with no reperfusion than the standard pulmonary arterial embolization.

Large pulmonary arteriovenous malformations: long-term results of embolization with AMPLATZER vascular plugs

PURPOSE

To analyze the long-term results of endovascular treatment of large pulmonary arteriovenous malformations (PAVMs) using the AMPLATZER vascular plug (AVP; AGA Medical Corp, Golden Valley, Minnesota).

MATERIALS AND METHODS

Between May 2007 and April 2011, 18 patients with 24 large PAVMs, defined as PAVMs that had a feeding artery with a diameter of ≥ 8 mm, were treated with AVP I or AVP II. A single AVP device was used for each PAVM. Aneurysmal sac diameters, sac perfusion, sac shrinkage, and complete resolution before and after the intervention were analyzed. Complete histories, laboratory values, physical examinations, and multidetector computed tomography images were reviewed. The mean occlusion time for AVP I and AVP II and the mean arterial oxygen saturation (SaO2) before and after the intervention were compared.

RESULTS

The mean diameter of the feeding artery was 11.46 mm ± 2.18 (range, 8-13.3 mm). The mean occlusion time was 7.34 minutes ± 1.23 for AVP I and 6.25 minutes ± 1.12 for AVP II (P = .11). The mean SaO2 before and after the intervention was 63.71% ± 8.10% (range, 51%-76%) and 96.28% ± 0.49% (range, 96%-97%), respectively (P = .045). No major periprocedural complications were observed. The mean follow-up duration was 36.33 months ± 10.63 (range, 28-56 mo). During the follow-up period, there were no persistent sac perfusions, migration of the AVPs, major complications, or recanalizations.

CONCLUSIONS

Treatment of large PAVMs with AVPs is an effective method for obtaining excellent long-term results. Embolization of large feeding arteries can be accomplished with AVPs without major complications.

Ischaemic stroke with intact atrial septum--exclude arteriovenous malformations

A 44-year-old woman was referred to our centre for interventional cardiac catheterisation. The diagnostic work-up after a preceding ischaemic stroke led to the assumption of a patent foramen ovale due to a positive bubble study. Before the planned percutaneous closure of the patent foramen ovale, we performed a second bubble study, which showed an intact atrial septum. However, after two to three heart cycles bubbles could be detected in the left atrium, assuming a right-to-left shunt of an extracardiac origin most likely in the lung. We therefore performed cardiac catheterisation, yielding a pulmonary arteriovenous malformation in the lower lobe of the right lung. This was successfully closed interventionally by placing a Cook coil, as well as several plugs into the malformation and feeding vessels.