First use of Micro Vascular Plugs in Australia: Endovascular treatment of pulmonary arteriovenous malformation

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.

Embolization of vascular abnormalities in children with congenital heart diseases using medtronic micro vascular plugs

This study aimed at evaluating our experience with Micro Vascular Plug (MVP) for embolization of vascular abnormalities in children with congenital heart diseases (CHDs). MVP is one of the most recent additions to the armamentarium for peripheral embolization. Data on its use in congenital cardiology are scarce. Medical records of children with CHDs who had embolizations with MVPs between April 2015 and September 2020 were reviewed. Immediate and follow-up data were assessed. A total of 153 patients underwent 172 procedures during which 240 embolizations using 259 MVPs were attempted. Median age and weight were 34.9 months (IQR, 4-75 months) and 12.5 kg (IQR, 4.8-19.4 kg), respectively. Targets were abnormal systemic arteries (n = 163), patent arterial ducts (n = 26), venous (n = 45), and coronary-cameral fistulas (n = 6). Median vessel diameter was 3.3 mm (IQR, 2.5-4 mm). Veins were larger than arteries (2.3 mm > 2.1 mm, p < 0.01). MVPs were implanted in narrower diameters compared to manufacturer's recommendations. Compared to veins, solitary implanted MVPs in arteries were additionally oversized at 12.4%, 5.1%, and 7.9% for MVP-3Q, 5Q, and 7Q, respectively. Additional occlusion material (16.7%) and 2 MVPs (5.8%) were needed at the same site for complete closure. Implantation and procedure success rates were 99.2% and 96.7%, respectively. Five complications were treated percutaneously (n = 4) and surgically (n = 1). Efficacy of vascular embolization using MVPs was demonstrated in the largest cohort of children with CHDs and a variety of clinical settings. Immediate and stable closure is obtained with a single device in most cases. Detailed device selection chart according to vessel type and diameter is proposed to achieve intended outcomes.

Embolization with MVP (Micro Vascular Plug®): experience on 104 patients in emergent and elective scenarios

AIM

To describe a 3 years experience of peripheral arterial embolization with Micro Vascular Plug (MVP) (Medtronic, USA).

MATERIALS AND METHODS

The following parameters were investigated: type of vascular injury, anticoagulation therapy at time of procedure, anatomical district, caliper of the target artery, course of the landing zone, additional embolics, technical and clinical success, device related clinical complications. Technical success was defined as complete embolization without deployment of additional embolics after MVP release. Primary clinical success was considered as hemodynamic stability in emergency setting and resolution of the underlying vascular pathology in elective cases; secondary clinical success was considered clinical success after a second embolization session.

RESULTS

116 MVP have been released in 104 patients (67 males and 37 females; mean age 61.3 years). The pullback release technique was adopted in each case. 85 patients were treated in emergent settings while in 19 patients the procedure was scheduled. The overall technical success was 75%. Primary clinical success was 96.1%, secondary clinical success 3% and clinical failure 0.9%. No statistical differences in terms of effectiveness were observed among patients assuming anticoagulation (p-value = 0.6). A straight and longer landing zone were statistically associated with higher technical success compared to curved and shorter ones, (p-values < 0.001 and = 0.048 respectively). MVP-3 and MVP-5 were the most frequently adopted models in this sample, in 29.8% and 49% of the patients respectively. No clinically adverse events directly related to MVP occurred; in 3 cases device migration was registered without clinical complications.

CONCLUSION

MVP is a safe and effective embolic agent. While eventual concomitant anticoagulation therapy did not influence the technical outcome, straight course and length of the landing zone are essential parameters to evaluate before deployment.

MVP (Micro Vascular Plug®) embolization of severe renal hemorrhages after nephrostomic tube placement

Background

We report our experience in managing iatrogenic renal bleedings after nephrostomic procedures by transarterial embolization using Micro Vascular Plug (MVP) (Medtronic, USA) as single or complementary embolization device with parenchimal sparing.

Materials and methods

Five patients have been treated in a single center with transarterial embolization because of renal hemorrhages occurring after positioning of nephrostomic drainages.

All patients presented with back pain, severe hematuria and/or bright red blood into the nephrostomic bag, with fall in hemoglobin value.

After contrast enhanced CT scan confirming arterial active bleeding, rescue embolization was performed using MVP.

The renal parenchimal loss was estimated on final postembolization DSA. Creatinine values were monitored before and after the procedure.

Results

Technical and clinical successes were obtained in all patients.

Two patients presented with extraluminal blush, one with multiple pseudoaneurysms, one with pseudoaneurysm with arterovenous fistula, one with extraluminal blush with arterovenous fistula.

MVP models were choosen oversized because of vasospasm that would underestimate the effective caliber of target vessel; MVP 3Q and MVP 7Q were adopted in one patient each, while MVP 5Q was released in three cases.

MVP was the sole embolizing agent in four patients; in one patient, MVP was employed after microcoils failed to obtain complete embolization.

The percentage of renal parenchimal lost was lower than 20%; no increase in Creatinine values was detected at dismission.

Conclusions

According to proposed data, MVP seems to be a safe, effective and fast embolizing device that interventionalists could consider when facing renal bleedings, even as sole agent.

Pulmonary arteriovenous malformations: what the interventional radiologist needs to know

Pulmonary arteriovenous malformations (PAVMs) or fistulas are rare direct pathological connections between pulmonary arterial and venous circulation. Most of PAVMs are congenital and closely associated with hereditary hemorrhagic telangiectasia, but acquired PAVMs have also been described in the literature. Diagnosis of PAVMs is a priority for clinicians, in order to prevent potentially fatal events such as cerebrovascular stroke, systemic septic embolization, hemoptysis and hemothorax. In this scenario, the radiologist plays a key role in both diagnostic and therapeutic workups of PAVMs: Chest X-ray, computed tomography and magnetic resonance are effective tools for PAVMs identification and confirmation of the suspected diagnosis. Furthermore, imaging modalities provide most of the elements for PAVMs classification according to their angioarchitecture (simple and complex) and help the clinicians in establishing which lesion requires prompt treatment and which one will benefit of imaging follow-up alone. Endovascular management of PAVMs has grown up as the first-line treatment in respect of surgery during last decades, showing lower risk of intra- and post-procedural complications and offering a wide number of treatment options and materials, ensuring effective management in virtually any clinical situation; interventional treatment aims to exclude PAVMs from pulmonary circulation, and specific technique and embolic agents should be selected according to pre-treatment imaging, in order to obtain the best procedural outcome. This paper proposes a review of the clinical and radiological features that a radiologist needs to know for PAVMs diagnosis and proper management, also showing an overview of the most common endovascular treatment strategies and embolization materials.

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.