Microvascular Plug Research Articles

ELECT: prospective, randomized trial comparing microvascular plug versus platinum-fibered microcoils for embolization of aneurysm sac side branches before endovascular aortic aneurysm repair

BackgroundPreemptive selective embolization of aneurysm sac side branches (ASSBs) has been proposed to prevent type II endoleak after endovascular aortic aneurysm repair (EVAR). This study aimed to explore if an embolization strategy using microvascular plugs (MVP) reduces intervention time and radiation dose compared to platinum-fibered microcoils. Furthermore, the effectiveness of the devices in occluding the treated artery was assessed.MethodsSixty patients scheduled for EVAR underwent percutaneous preemptive embolization of ASSBs using MVPs or coils after a 1:1 randomization. Follow-up imaging was performed during aortic stentgraft implantation.ResultsOverall, 170 ASSBs were successfully occluded (83 arteries by MVPs and 87 by coils) and no acute treatment failure occurred. The mean procedure time was significantly lower in the group treated with MVPs (55 ± 4 min) compared to coil occlusion (67 ± 3 min; p = 0.018), which was paralleled by a numerically lower radiation dose (119 Gy/cm2 vs. 140 Gy/cm2; p = 0.45). No difference was found for contrast agent use (34 ml MVP group vs 35 ml coil group; p = 0.87). At follow-up, reopening of lumbar arteries was seen in nine cases (four after coil embolization; five after MVPs).ConclusionBoth microvascular plugs and coils can be effectively used for preemptive embolization of aneurysm sac side branches before EVAR. Use of plugs offers a benefit in terms of intervention time.Trial registrationClinicalTrials.gov Identifier: NCT03842930 Registered 15 February 2019.Graphical

Complex retrograde transarterial access and embolization of a giant internal iliac artery aneurysm after occlusion failure of Micro vascular plug (MVP) embolization and preceding EVAR in the distal ectatic Aorta and bilateral iliac artery aneurysms

The therapy of pelvic aneurysms is minimally invasive through interventional radiology using various devices and embolic agents: 
 1. By using a covered stent/prosthesis to maintain antegrade flow when a landing zone, i.e., a
 vascular segment angiographically present into which the stent can be placed to bridge the neck of the aneurysm, thereby interrupting aneurysm perfusion. 
 2. Through complete embolization of the aneurysm using embolic agents/coils. 
 3. As performed in our case, by covering the aneurysm (Img 14 A-C) with a covered stent /prosthesis, following prior embolization of the branching vessels using macroembolic agents. In cases where there is insufficient occlusion of the aneurysm with residual perfusion, secondary em- bolization becomes considerably more complex due to the occlusion of the anatomically antegrade access and the altered hemodynamics around the aneurysm causing retrograde collateralization. Through detailed analysis of CT angiography, even in static CT, retrograde circulation could be iden- tified, allowing for a minimally invasive secondary approach to the aneurysm without the need for general anesthesia and/or surgery. By completely eliminating the aneurysm, the risk of rupture in the elderly patient was minimally invasively eliminated. The treatment of this patient exemplifies the possibilities that embolization with a wide array of embolic agents and catheters offers in a hemo- dynamically very complex situation.

Modified Medtronic Microvascular Plug Implantation to Reduce Pulmonary Blood Flow in Patients With a Shunted Single Ventricle

Modified Medtronic Microvascular Plug Implantation to Reduce Pulmonary Blood Flow in Patients With a Shunted Single Ventricle

Transcatheter Pulmonary Artery Banding in High-Risk Neonates: In-Vitro Study Provoked by Initial Clinical Experience.

Very high-risk, ductal-dependent or complex two-ventricle patients with associated comorbidities often require pulmonary blood flow restriction as bridge to a more definitive procedure, but current surgical options may not be well-tolerated. An evolving alternative utilizes a fenestrated Micro Vascular Plug (MVP) as a transcatheter, internal pulmonary artery band. In this study, we report a case series and an in-vitro evaluation of the MVP to elicit understanding of the challenges faced with device implantation. Following single-center, retrospective review of eight patients who underwent device placement, an in-vitro flow study was conducted on MVP devices to assess impact of device and fenestration sizing on pulmonary blood flow. A mathematical model was developed to relate migration risk to vessel size. Results of the engineering analysis were compared to the clinical series for validation. At median follow-up of 8months (range 1-15), survival was 63% (5/8), and 6 (75%) patients underwent subsequent target surgical intervention with relatively low mortality (1/6). Occluder-related challenges included migration (63%) and peri-device flow, which were evaluated in-vitro. The device demonstrated durability over normal and supraphysiologic conditions with minimal change in fenestration size. Smaller vessel size significantly increased pressure gradient due to reduced peri-device flow and smaller effective fenestration size. Device oversizing, with appropriate adjustment to fenestration size, may reduce migration risk and provide a clinically appropriate balance between resulting pressure gradient and Qp:Qs. Our results can guide the interventionalist in appropriately selecting the device and fenestrations based on patient-specific anatomy and desired post-implantation flow characteristics.

Novel Technique for Intentional Occlusion of Directional Branches During Complex Endovascular Aortic Repair Using Microvascular Plugs.

To demonstrate the feasibility and outcomes of using the microvascular plug (MVP) for intentional occlusion of directional branches (DB) during complex endovascular aortic procedures. Two patients were treated with the off-the-shelf four-branched Zenith t-Branch thoracoabdominal stent-graft (Cook Medical, Bloomington, Ind). In both cases, the renal arteries (on one side in patient #1 and on both sides in patient #2, respectively) were occluded at time of index intervention. Preoperative planning included the intentional occlusion of each DB with one 7Q-MVP. Technical success was achieved in all cases and maintained at mid-term follow-up (12months and 36months, respectively). Use of the MVP appears to be feasible and effective for intentional occlusion of DB during complex endovascular aortic repair. This novel and simple technique may present some unique technical advantages, allowing precise placement of the device while avoiding extension using a bridging stent and DB cannulation with larger sheaths.

Transcatheter Closure of a Coronary Artery Fistula in a Neonate with Tetralogy of Fallot.

Coronary artery-to-pulmonary artery fistulae are a not uncommon finding in patients with Tetralogy of Fallot (TOF) and collateral-dependent pulmonary blood flow. Management for these fistulae is often primary surgical ligation or unifocalization at the time of complete repair, dependent on the presence of dual blood flow to the involved areas. We present the case of a 32-week premature boy weighing 1.79kg with TOF, confluent branch pulmonary arteries, major aortopulmonary collaterals, and right coronary artery to main pulmonary artery fistula. The patient demonstrated evidence of coronary steal into the pulmonary vasculature with an elevation in the troponin level without hemodynamic instability, and subsequently underwent successful transcatheter occlusion of the fistula via right common carotid access using a Medtronic 3Q microvascular plug. This case demonstrates the realistic potential for early coronary steal in this physiology and possibility of transcatheter therapy even in a small neonate.

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

Micro-vascular plug (MVP) is one of the most recent addition to the armamentarium for peripheral embolization. Data on its use in congenital cardiology is scarce. We aim to evaluate our experience with MVP for embolization of vascular abnormalities in children with congenital heart diseases (CHDs). 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 comprehensively 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). Targets were abnormal systemic arteries ( n = 163), patent arterial ducts ( n = 26), venous ( n = 45), and coronary-cameral fistulas ( n = 6). The 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 the 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). The safety and efficacy of vascular embolization using MVPs were demonstrated in the largest cohort of children with CHDs and in a variety of clinical settings. Immediate and stable closure is obtained with a single device in most cases. A detailed device selection chart according to vessel type and diameter is proposed to achieve intended outcomes.

Iatrogenic arterio-biliary fistula and peripheral hepatic artery pseudoaneurysm after transjugular liver biopsy: complication management using a microvascular plug

This study aimed to report on complication management in a 58-year-old woman referred for transjugular biopsy for the evaluation of unknown liver disease. After an initial uneventful biopsy procedure, the patient complained of severe upper abdominal pain. Laboratory tests revealed increasing liver enzymes. Imaging studies depicted an iatrogenic pseudoaneurysm associated with an arterio-biliary fistula originating from the right peripheral hepatic artery. Angiography and percutaneous transarterial superselective embolotherapy was performed by means of a microcatheter and microvascular plug. Precise device positioning allowed for successful closure of the bleeding site without compromising the hepatic vasculature.

Intrahepatic flow diversion prior to segmental Yttrium-90 radioembolization for challenging tumor vasculature

BackgroundHepatic tumors with complex vascular supply or poor relative perfusion are prone to decreased rates of objective response. This is compounded in the setting of Yttrium-90 (Y90) transarterial radioembolization (TARE), which is minimally embolic and flow-dependent, relying on high threshold dose for complete response. ObjectiveWe describe our experience with intrahepatic flow diversion (FD) prior to TARE of hepatocellular carcinoma (HCC) with challenging vascular supply. Materials and methodsBetween April 2014 and January 2020, 886 cases of coinciding MAA or TARE and bland embolization or temporary occlusion were identified. Intraprocedural embolizations performed for more routine purposes were excluded. FD was performed by bland embolization or temporary occlusion of vessels supplying non-malignant parenchyma in cases where flow was not preferential to target tumor. Lesion characteristics, vascular supply, treatment approach, angiography, and adverse events (AEs) were reviewed. Radiographic response was assessed using mRECIST criteria. Results22 cases of FD of focal HCC were identified. Embolics included calibrated microspheres (n ​= ​11), microcoils (n ​= ​4), gelfoam (n ​= ​3), temporary balloon occlusion (n ​= ​2) and temporary deployment of a microvascular plug (n ​= ​1). Post-treatment SPECT-CT dosimetry coverage was concordant with target lesions in all cases. Mean follow-up was 16.7 months (1.4–45 ​mos). Tumor-specific response per mRECIST was 41% complete response, 50% objective response, and 59% disease control rate. No major adverse events or grade 3/4 hepatotoxicity were reported. ConclusionOur findings suggest that FD prior to TARE is safe and potentially effective in treating HCC with complex vascular supply or poor tumor perfusion.

Institutional Trend in Device Selection for Transcatheter PDA Closure in Premature Infants

We report our experience with transcatheter patent ductus arteriosus (PDA) closure in premature infants and compare patients grouped by the device used for closure: the Microvascular Plug, “MVP” (Medtronic, Minneapolis, MN); Micro Plug Set, “Micro Plug” (KA Medical, Minneapolis, MN); and Amplatzer Piccolo Occluder, “Piccolo” (Abbot, Santa Clara, CA). We also report trends in device selection over time. Studies examining outcomes according to device selection for PDA closure in premature infants are lacking. We performed a retrospective review of all percutaneous PDA closures in premature infants at a single center (June 2018–May 2021). Patients were grouped by initial device selected for PDA closure (intention to treat). Institutional Review Board approval was obtained. 58 premature infants [MVP (n = 25), Micro Plug (n = 25), and Piccolo (n = 8)] underwent successful transcatheter PDA closure (mean gestational age 27 weeks 2 days; mean weight at procedure 1.4 kg; mean age at procedure 28 days). Pre-procedural demographics, procedural data, and follow-up data were similar between groups. There were no significant procedural adverse events. Three devices (2 MVP, 0 Micro Plug, 1 Piccolo p = 0.27) embolized after the procedure. One other device was removed for concern for aortic obstruction. Device selection evolved with a clear trend toward the Micro Plug device over time. Demographic, procedural, and follow-up data were similar between the MVP, Micro Plug, and Piccolo groups. The Micro Plug did not require exchange for suboptimal fitting or embolize and became our preferred device in most cases.

Use of the Medtronic Microvascular Plug 7Q for transcatheter closure of large patent ductus arteriosus in infants weighing less than 2.5 kg.

BackgroundThe sole Food and Drug Administration‐approved device for transcatheter closure of the patent arterial duct in premature infants is indicated for patent ductus arteriosus (PDAs) ≤ 4 mm in diameter. We report a two‐center experience with transcatheter closure of large PDAs (>4 mm) in infants weighing <2.5 kg using the Microvascular Plug 7Q (MVP‐7Q) device.MethodsThis is a retrospective review of departmental databases and medical charts to define patient cohort and report demographic, procedural, and follow‐up data.ResultsTwenty‐two patients (12 male) with a median gestational age and birthweight of 25.5 weeks (interquartile range [IQR] = 24–28) and 800 g (572–1075), respectively, underwent attempted PDA occlusion with the MVP‐7Q using a transvenous approach. The median age and weight at the time of PDA occlusion was 32 days (IQR = 24–28) and 1100 g (IQR = 960–1700), respectively. The median PDA length was 12 mm (IQR = 11–12.65). The median PDA diameters at the aortic and pulmonary ends were 5.1 (IQR = 4.9–5.5) and 4.8 mm (IQR = 4.6–5.3), respectively. Successful device occlusion was achieved in 20 patients (91%). There were two failed attempts: One due to inappropriate sizing, and the other secondary to left pulmonary artery stenosis. There were no procedural complications and no residual shunting on follow‐up.ConclusionsThe MVP‐7Q is safe and effective for transcatheter closure of large (>4 mm) PDAs in infants <2.5 kg. The lack of retention disks may help with avoiding impingement on surrounding vessels.

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 of153 patients underwent 172 procedures during which 240 embolizations using 259 MVPs were attempted. Median age and weight were 34.9months (IQR, 4-75months) and 12.5kg (IQR, 4.8-19.4kg), 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 3.3mm (IQR, 2.5-4mm). Veins were larger than arteries (2.3mm > 2.1mm, 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.

Successful Use of Neurovascular Plug for Embolization of Scalp Arteriovenous Fistula: A Novel Technique

Purpose: We report a case of a pediatric patient developing a delayed-onset scalp arteriovenous fistula (AVF) and pseudoaneurysm managed with a new technique. Technique: A 10-year-old boy presented to the outpatient clinic complaining of a growing pulsatile mass in the right side of the skull after head trauma 6 months ago. He had no neurological deficits. Imaging studies revealed scalp AVF with pseudoaneurysm. The arterial feeding was from the right temporal artery, while the blood was drained into the superior sagittal sinus and the facial vein. The fistula was occluded successfully by a microvascular plug (MVP). Follow-up angiography 1 year later showed that the AVF was no longer seen with complete embolization of pseudoaneurysm, total occlusion of the abnormal vessels, and the absence of MVP migration. Conclusion: To the best of our knowledge, we report the first case of successfully using MVP to treat scalp AVF. The MVP is a novel technique with its unique ability to achieve rapid, safe, effective, and permanent vascular occlusion through a single device. Besides, the possibility of delayed-onset traumatic vascular injuries should be considered in a patient with head or facial trauma.

Abstract 13315: Feasibility and Effectiveness of Using a Modified Microvascular Plug to Reduce Pulmonary Blood Flow for Various Congenital Heart Diseases

Background: Neonates with certain congenital heart diseases (CHD) experience pulmonary overcirculation requiring a sternotomy for either pulmonary artery banding or neonatal corrective surgery. We present an alternative, percutaneous technique of utilizing custom fenestrated microvascular plug (MVP) as pulmonary flow reducers (PFR) for five different CHDs complicated by pulmonary overcirculation in the newborn. Methods: Fourteen PFRs were implanted percutaneously via a femoral venous only approach under fluoroscopic and echocardiographic guidance in nine neonates for five different CHDs. The success rates, complications, effectiveness and follow-up details are described. Results: All 14 PFRs were successfully implanted in the desired locations in with no procedural failures or complications. Bilateral PFRs were implanted within the branch pulmonary arteries in two patients to balance pulmonary and systemic circulations in single ventricle physiology and in three patients to reduce left-to-right shunt physiology. Single PFRs were placed within the patent ductus arteriosus (PDA) in one patient with a PDA stent who developed pulmonary overcirculation and three patients with large PDAs and pulmonary hypertension. Effectiveness was assessed either by a 10% drop in systemic oxygen saturation, &gt; 35 mmHg Doppler gradient, or weaning off diuretics depending on the indication. On latest follow-up, there were no PFR related mortality or re-interventions. Conclusion: It is feasible to modify and implant the MVP to function as an effective PFR for various congenital heart lesions in neonates. Outcomes following explanation such as, pulmonary artery growth, re-interventions rates are unknown. Once the learning experiences are overcome, longer term comparison studies are necessary to demonstrate benefits over existing therapies.

Medtronic microvascular plug™: A multipotent device for transcatheter occlusions in children with congenital heart disease

To evaluate our experience with the MVP™ Microvascular Plug system for embolizations of vascular abnormalities in children with congenital heart diseases (CHD). The MVP™ is a recent valuable addition to the armamentarium for vascular embolization. Data on its use in pediatric and congenital cardiology is scarce. Medical records and catheterization reports of all children with CHD who had attempted transcatheter embolizations with MVP™ between April 2015 and September 2020 were retrospectively reviewed. Type of lesions, immediate procedural outcomes, and follow-up data were assessed. A total of 153 patients underwent 172 procedures during which 240 vessel embolizations using 259 MVP™ were attempted. Median age and weight were 34.9 months and 12.5 kg, respectively. Two devices were deployed at the same site in 14 cases. Seven devices were removed before release. Procedural success rate was 99.2%. Target vessels anomalies were systemic arteries ( n = 163), patent arterial duct ( n = 26), venous ( n = 45), and coronaro-cameral fistulae ( n = 6). Mean vessel diameter was 3.3 ± 1.1 mm (1.4 to 9 mm). A detailed device selection chart according to vessel type and diameter was presented based on our experience ( Table 1 ). Complete closure rate was 94.4% at the end of the procedure and increased up to 100% across follow-up. Major complications were limited to one device migration requiring surgery and 4 embolizations treated with percutaneous retrieval. Safety and efficacy of abnormal vessel embolization using the MVP™ were demonstrated in the largest cohort of children with CHD and in a variety of applications. The major advantages of the MVP™ are smooth delivery with high procedural flexibility leading to immediate and stable closure with a single device in most cases, potentially reducing duration, radiation exposure, and decreasing the size of the sheath used in small children.

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

AimTo describe a 3 years experience of peripheral arterial embolization with Micro Vascular Plug (MVP) (Medtronic, USA).Materials and methodsThe 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.Results116 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.ConclusionMVP 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.

Endovascular treatment of iatrogenic superior mesenteric arteriovenous fistula resulting in recurrent abdominal ascites

Superior mesenteric arteriovenous fistulas (AVFs) are rare and are usually caused by previous bowel surgery or blunt abdominal trauma. Patients may be asymptomatic, have non-specific symptoms of abdominal pain, nausea and vomiting or present with symptoms of portal hypertension; some patients may present years after initial surgery or trauma. Traditionally, superior mesenteric AVFs are treated by surgical ligation. However, percutaneous endovascular treatment has become increasingly popular in recent years. Different options of endovascular treatment include coil embolisation, covered stent and vascular plugs. There is a risk of coil migration with coil embolisation and covered stents may cause abnormal vessel straightening. Vascular plugs allow the fistula to be treated with fewer devices and have minimal risk of migration. Newer devices such as microvascular plugs have the added advantage of being able to be delivered through microcatheters or diagnostic catheters. The smaller profile of the microvascular plug also allows it to navigate through tortuous vessels. We report a case of a 77-year-old patient presenting with recurrent abdominal ascites three years after small bowel resection. CT and angiogram demonstrated a superior mesenteric AVF, which was successfully treated with a combination of microvascular plug and coil. He remained relatively asymptomatic four months after treatment.

Increasing Yttrium-90 Dose Conformality Using Proximal Radioembolization Enabled by Distal Angiosomal Truncation for the Treatment of Hepatic Malignancy

PurposeTo evaluate safety and feasibility of improving radiation dose conformality via proximal radioembolization enabled by distal angiosomal truncation where selective administration was not practical. Materials and MethodsHepatic malignancies treated via angiosomal truncation between January 2017 and March 2019 were retrospectively evaluated. Thirty-three patients (8 women, 25 men; mean age, 62.2 y; range, 36–78 y) underwent 39 treatments. Of treatments, 74.3% (n = 29) were for hepatocellular carcinomas, 10.2% (n = 4) were for cholangiocarcinomas, and 15.4% (n = 6) were for metastatic tumors (1 colorectal adenocarcinoma, 1 pancreatic adenocarcinoma, 3 melanomas, and 1 endometroid carcinoma). Truncation was achieved using temporary embolic devices including a microvascular plug, detachable coil, gelatin slurry, and balloon microcatheter, after which proximal radioembolization was performed. Range of treatment activity was 0.47–5.75 GBq. Technetium-99m macroaggregated albumin and bremsstrahlung single photon emission computed tomography (CT)/CT threshold analysis was conducted to delineate and compare distribution of activity within the treatment angiosome before and after radioembolization. ResultsDosimetric analysis of 14 patients demonstrated a significant reduction in nontarget liver radiation exposure at 5, 20, and 40% thresholds (P = .002, P = .001, and P = .008, respectively). There were no grade 3 or higher adverse events. There was no significant change in Albumin-Bilirubin grade and Eastern Cooperative Oncology Group Performance Status (P = .09 and P = .74) before and 3 months after the procedure. Truncated arteries were patent on subsequent angiography in 11 cases and on MR angiography or CT angiography in 38 of 39 cases. ConclusionsProximal radioembolization enabled by distal angiosomal truncation is safe and decreases nontarget parenchymal radioembolization dose in cases not amenable to selective administration.

Initial Experience With the Microvascular Plug in Selective Renal Artery Embolization

To evaluate the safety and efficacy of the microvascular plug (MVP) for selective renal artery embolization. Retrospective review was performed on a cohort of 6 patients undergoing renal artery embolization using the MVP between July 2015 and August 2018. Patients' demographics, indication for embolization, technical details of the embolization procedure, and clinical events were gathered from the patients' electronic medical records. The patients underwent selective renal artery embolization with a MVP for iatrogenic vascular injuries (n = 3), traumatic vascular injuries (n = 2), and for elective embolization of an angiomyolipoma (n = 1), in native kidneys (n = 4) or in renal allografts (n = 2). Immediate occlusion of the feeding artery was achieved with 1 MVP device in 4 patients. In 1 patient, a second MVP was needed, and in another patient, additional 0.018-inch microcoils were used to completely occlude the injured artery. Technical success was achieved in all patients. The volume of the resulting renal infarction was estimated less than 5% of the renal volume. No other procedure-related complications occurred. The MVP is a safe and effective device allowing superselective renal artery embolization. Therefore, we recommend the MVP as a valuable embolic in superselective renal artery embolization. Additionally, a single device is sufficient in most cases, potentially reducing the cost, duration, and radiation exposure of the procedure.

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

BackgroundWe 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 methodsFive 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.ResultsTechnical 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.ConclusionsAccording 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.