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Friday, May 15, 2020

Impact of Renal Function Trajectory on Renal Replacement Therapy and Mortality Risk after Renal Artery Revascularization


Clinical question
What is the impact of renal function trajectory, defined as the change in renal function over time before and after renal artery stent placement, on long-term risk for renal replacement therapy (RRT) and mortality?

Take-away point
Post intervention eGFR trajectory improvement approaching 40 mL/min/1.73 m2 was associated with decreased RRT and mortality risk, indicating that patients with advanced CKD and renal artery stenosis may benefit from revascularization.

Reference
Takahashi, Edwin A. et al. Impact of Renal Function Trajectory on Renal Replacement Therapy and Mortality Risk after Renal Artery Revascularization. Journal of Vascular and Interventional Radiology, Volume 31, Issue 4, 592 – 597.

Click here for abstract

Study design
Retrospective review

Funding source
Self-funded or unfunded

Setting
Single institution







Figure 1. Kaplan–Meier estimates for freedom from the need for RRT after renal artery stent placement. Fourteen patients were started on RRT, 16 died, and 9 were lost to follow-up within 1 year of intervention, resulting in an initial number at risk of 359 patients.


Summary


Evidence in support of aggressive diagnosis and revascularization of renal artery stenosis is evolving. Data on renal function trajectory is lacking. The authors of this study evaluated the effect of renal artery stenting on renal replacement therapy (RRT)-including hemodialysis and transplantation-in addition to all-cause mortality based on renal function change from 6-12 months before intervention to the time of intervention and from the time to intervention to 6-12 months after intervention.

Retrospective review of 398 patients who underwent renal artery stenting was performed. Renal artery stent placement was performed if Doppler US showed a main renal artery peak systolic velocity >180 cm/s or a renal-to-aortic radio >3.5. Angiographically, stenoses greater than or equal to 50% were treated with angioplasty followed by balloon-expandable bare-metal stent placement without distal embolic protection. Bilateral renal artery stenosis was treated in 162 patients (41%). Primary outcome was impact of estimated glomerular filtration rate (eGFR) on the incidence of RRT and mortality. Potential contributing factors to RRT such as medications, 24-hour proteinuria, presence of CKD, coronary artery disease, diabetes, and smoking were analyzed.

Of the 398 patients, 14 started RRT, 16 died, and 9 were lost to follow-up within 1 year of the procedure. The RRT-free survival rate at 5 years was 92.1% (95% CI, 88.0%–96.1%). 248 patients died after 6–12-month post-intervention (5 year mortality risk of 60.3%). Mean pre-interventional, time-of-intervention, and post-interventional eGFR measurements were 48.3 mL/min/1.73m2±18.7, 42.5 mL/min/1.73 m2±17.8, and 45.5 mL/min/1.73 m2±20.1, respectively. The eGFR trajectory from 6–12 months before intervention to the time of intervention was not significantly associated with risk for RRT or all-cause mortality (P=.47 and P=.45, respectively). However, the eGFR trajectory from intervention to 6–12 months after intervention was significantly associated with freedom from RRT (P=.02). This change was not associated with freedom from all-cause mortality (P=.21). Among patients with a post-interventional eGF<40 mL/min/1.73 m2, for a 1-unit eGFR increase up to 40 mL/min/1.73 m2, there was a significant decrease in RRT risk (HR, 0.87; 95% CI, 0.83–0.91; P<.001) as well as all-cause mortality risk (HR,0.95; 95% CI, 0.94–0.97; P<.001). However, patients with an eGFR>40 mL/min/1.73 m2 at 6–12 months after intervention did not experience lower incidences of RRT or death. Higher rates of RRT were seen with diabetes at the time of intervention, increased baseline proteinuria, and stage 4/5 CKD. On univariate analysis, higher mortality rates were seen in patients with diabetes, increased baseline proteinuria, and stage 4 CKD. On multivariate analysis, higher mortality was seen with diabetes was the only comorbidity associated with increased mortality.

Commentary


Following the CORAL trial, it is encouraging to see data which may support a greater role for renal artery stenting for renovascular hypertension. The main finding of this study is that eGFR less than or equal to 40 mL/min/1.73 m2 after intervention has a beneficial effect on RRT and mortality. However, this study does have limitations in that the criteria for and severity of hypertension and renal dysfunction were not described and that hemodynamic significance of renal artery lesions were determined by a threshold of 50% or more stenosis on angiography, without pressure measurements. Dr. Sos discusses these limitations and others in a thorough commentary. More work on renal artery stenting in the form of large, prospective, randomized trials are necessary.

Post Author
Zagum Bhatti, MD
Assistant Professor
Department of Radiology, Interventional Radiology Division
University of Texas Health Science Center at Houston, Houston, TX
@ZagumBhatti

Monday, May 11, 2020

Efficacy and Safety of Ultrasound-Guided Supraclavicular Brachial Plexus Block during Angioplasty of Dysfunctional Arteriovenous Access: A Prospective, Randomized Single-Center Clinical Trial


Clinical question

Is ultrasound-guided supraclavicular brachial plexus block (BPB) helpful in reducing pain prior to angioplasty of dysfunctional arteriovenous (AV) access?

Take-away point
Patients randomized to supraclavicular BPB prior to intervention on their AV access showed lower average pain scores with better patient satisfaction compared to the control group with no major immediate or delayed complications.

Reference
Heo, S., Won, J. H., Kim, J., Kim, J. Y. & Joe, H. B. Efficacy and Safety of Ultrasound-Guided Supraclavicular Brachial Plexus Block during Angioplasty of Dysfunctional Arteriovenous Access: A Prospective, Randomized Single-Center Clinical Trial. J. Vasc. Interv. Radiol. 31, 236–241 (2020).

Click here for abstract

Study design
Single-center prospective clinical trial of 80 participants between November 2016 and February 2018 randomized to either ultrasound-guided supraclavicular BPB or no regional anesthesia. Primary endpoints included pain assessment and patient satisfaction evaluation. Secondary endpoints included AV access patency at 6-month follow up as well as short- and long-term complications.

Funding source
N/A

Setting
Departments of Radiology and Anesthesiology and Pain Medicine at Ajou University School of Medicine, Suwon, Korea




Figure 2. Ultrasound-guided BPB procedure. The 23-gauge needle is first advanced to the inferior border of the brachial plexus (a), and 15 ml of anesthetic mixture is injected, resulting in superficially floating plexus bundle (b). The needle is then directed to the superior border of the brachial plexus, injecting another 15 ml of mixture (c). The procedure results in complete encasement of the brachial plexus by the injected mixture (d). M = medial; L = lateral.

Summary


Percutaneous balloon angioplasty of AV access is often painful. While moderate sedation can help alleviate pain during intervention, these medications can be associated with respiratory depression in an otherwise high-risk patient population. This study was developed to evaluate the anesthetic effect and safety of ultrasound-guided supraclavicular BPB for pain control during angioplasty of dysfunctional dialysis access—a method frequently utilized during upper extremity surgery.

Eighty participants with either insufficient flow or no flow in their upper extremity AV fistula or graft were randomized to supraclavicular BPB prior to angioplasty versus a control group. All procedures including BPB and dialysis access angioplasty were performed by the same two interventional radiologists who were not involved in the randomization process. There was no significant difference between groups regarding the reason for dialysis access dysfunction (P= .29) or the type/location of access (P=.82).

A mixture of 10 cc 0.75% ropivacaine, 10 cc of 2% lidocaine and 10 cc of normal saline was utilized for the purposes of supraclavicular BPB administered via the “double injection” technique at both the inferior and superior aspects of the plexus under ultrasound guidance. Procedure success was determined by motor and sensory changes to 0. Time to full block as well as time to recovery from motor and sensory deficit was recorded. Pain in the control group was managed with intravenous administration of 50 mg Tramadol and 5-10 cc of 2% lidocaine subcutaneous injection at the puncture site.

Procedure-related pain was evaluated by the Visual Analogue Scale from 0 (no pain) to 10 (unbearable pain) in both groups. Patient satisfaction was evaluated by a grade from 1 (not satisfied) to 3 (satisfied). Six-month follow up was performed either in outpatient clinic or over the phone.

All BPB procedures were technically successful with an average time to complete neurologic deficit of 10.7 +/- 5.1 minutes. The average neurologic recovery time from BPB was 7 hours and 56 minutes. The visual analogue pain scale was significantly lower (P < .001) and participant satisfaction was significantly higher (P < .001) in the BPB group compared to the control. Six-month patency of the AV access was not significantly different in the two groups (P = .59). There were no major complications.

Commentary


This is the first prospective randomized trial to evaluate the safety and efficacy of supraclavicular BPB prior to angioplasty of dysfunctional dialysis access elucidating the benefits for pain management during intervention. The authors successfully demonstrated reduction in pain score and improvement in patient satisfaction with supraclavicular BPB without short- or long-term complications.

In this study protocol, supraclavicular BPB was consistently performed by the same highly experienced interventional radiologists prior to angioplasty. Similar protocols may be difficult to simulate in institutions where nerve blocks are traditionally performed by anesthesiologists who may not be readily available for assistance in the immediate periprocedural period with potential for delay of intervention. Conversely, supraclavicular BPB performed by less experienced interventional radiologists may prolong total intraprocedural time.

The primary method of intraprocedural pain management in the control group was intravenous tramadol. Since many institutions continue to utilize moderate sedation with intravenous fentanyl and versed during dialysis access interventions, direct comparison of the authors’ protocol for supraclavicular BPB and moderate sedation may be beneficial in future studies.

The authors describe potential limitations including use of a single mixture/concentration of anesthetic in the BPB group as well as potential bias resulting in prolonged recovery from motor and sensory deficit. As demonstrated by the authors, diligent patient education and monitoring must be maintained in the post-procedural period to prevent injury from nerve deficit if supraclavicular BPB is utilized.

Post Author
Teodora Bochnakova MD
Assistant Professor
Department of Interventional Radiology
Oregon Health and Science University, Portland, OR
@T_bochnakova

Friday, May 8, 2020

Factors Affecting Recurrent Deep Vein Thrombosis after Pharmacomechanical Thrombolysis and Left Iliac Vein Stent Placement in Patients with Iliac Vein Compression Syndrome


Clinical question

Are there factors associated contralateral and ipsilateral recurrent deep vein thrombosis (DVT) after thrombolysis and stent placement in patients with iliac vein compression syndrome (IVCS)? Is overextension of the stent associated with contralateral or ipsilateral recurrent DVT?

Take-away point
Extension of iliac vein stent to the inferior vena cava (IVC) and in-stent thrombosis are associated with contralateral DVT. Thrombophilia, remaining IVC filter, and in-stent thrombosis are associated with ipsilateral DVT.

Reference
Factors Affecting Recurrent Deep Vein Thrombosis after Pharmacomechanical Thrombolysis and Left Iliac Vein Stent Placement in Patients with Iliac Vein Compression Syndrome. Kim, K.Y., Hwang, H.P., Han, Y. Journal of Journal of Vascular and Interventional Radiology (JVIR), Volume 31, Issue 4, 635-643. 

Click here for abstract

Study design
Single arm, retrospective, single-center study of 130 patients with left lower extremity thrombosis who underwent thrombolysis and stent placement with a median follow-up of 14 months and standardized 6-month anticoagulation followed by lifelong antiplatelet therapy.

Funding source
No reported funding

Setting
Academic hospital, Jeonbuk National University Medical School and Hospital, South Korea.




Figure 1. Categorization of stent position: (a) 100% coverage from the confluence to the contralateral wall of the inferior vena cava; (b) 50%–100% coverage; and (c) less than 50% coverage. (d) A diagram illustrating the three categories, respectively.

Summary


Left iliac stent placement after pharmaceutical thrombolysis in patients with iliac vein compression syndrome (IVCS) is safe and effective. However, precise placement remains challenging. Overly caudal placement may lead to stent collapse with caudal migration. Overly cranial placement may lead to overextension into the inferior vena cava (IVC) with implications of contralateral deep vein thrombosis (DVT). Analyses with a multi-factorial approach remain scarce regarding potential contributing factors to contralateral and ipsilateral recurrent DVT.

The authors performed a retrospective single-center study of 130 patients who underwent pharmaceutical thrombolysis and iliac vein stent placement for IVCS, categorized into 3 groups based on the left iliac stent’s IVC extension (Figure 1). Patients lost to follow-up within 3 months were excluded. Hypercoagulable work up was performed in 105 patients. IVC filter was placed in 111 patients. All filters were removed within 2 months after placement. Mechanical thrombectomy was performed in mixed-stage cases. Pre-stent balloon angioplasty was followed by stent placement oversized 10-20%. All patients were prescribed anticoagulation for 6 months followed by lifelong antiplatelet therapy. Median follow-up was 14 months. Univariate and multivariate analysis were performed between clinically relevant factors and development of contralateral and/or ipsilateral DVT.

7 and 11 patients developed contralateral and ipsilateral DVT, respectively. Contralateral DVT tend to occur later compared to ipsilateral DVT (median of 26 and 1 month, respectively). 2/7 and 5/7 contralateral DVT occurred before and during the 6-month anticoagulation period, respectively. 7/11 and 4/11 ipsilateral DVT occurred before and during the 6-month anticoagulation period, respectively. In-stent thrombosis and stent location (100% overextension into IVC) were associated with contralateral DVT. Thrombophilia, remaining IVC filter, and in-stent thrombosis during follow-up were associated with ipsilateral DVT.

Commentary


The authors in this paper examined a focused group of IVCS patients undergoing pharmaceutical thrombolysis and left iliac vein stent placement with relatively standardized workup and management. Results demonstrated in-stent thrombosis was associated with contralateral and ipsilateral DVT; overextension associated with contralateral DVT; and thrombophilia and remaining IVC filter associated with ipsilateral DVT. These results suggested that overextension into the IVC should be restrained to decrease risks of contralateral DVT. In addition, earlier IVC filter retrieval may be considered to decrease risks of ipsilateral DVT. Lastly, patients with thrombotic disease may warrant more frequent follow-ups to ensure stent patency. Although limited by its retrospective nature, variety of stents and IVC filters used, and small number of recurrent DVTs, this study has provided important information on iliac stent placement location and management of patients with IVCS.

Post AuthorNingcheng (Peter) Li, MD, MS
Integrated Interventional Radiology Resident, PGY-3
Department of Interventional Radiology
Oregon Health and Science University, Dotter Interventional Institute
@NingchengLi

Monday, May 4, 2020

Minimally Invasive Image-Guided Ablation, Osteoplasty, Reinforcement, and Internal Fixation (AORIF) for Osteolytic Lesions in the Pelvis and Periarticular Regions of Weight-Bearing Bones


Clinical question

Is AORIF a safe and effective surgical alternative to treat lytic metastases in periarticular load-bearing bones?

Take-away point
AORIF is a safe and effective treatment for symptomatic osteolytic metastases in load-bearing bones.

Reference
Lee FY, Latich I, Toombs C, et al. Minimally Invasive Image-Guided Ablation, Osteoplasty, Reinforcement, and Internal Fixation (AORIF) for Osteolytic Lesions in the Pelvis and Periarticular Regions of Weight-Bearing Bones. J Vasc Interv Radiol. 2020;31(4):649–658.e1. doi:10.1016/j.jvir.2019.11.029

Click here for abstract

Study design
Single-center, prospective clinical cohort

Funding source
Research support from the National Cancer Institute and National Institute of Arthritis and Musculoskeletal and Skin Diseases

Setting
Academic hospital, Yale School of Medicine, United States.




Figure 1. Illustrated details of the AORIF procedure.

Summary


Image guided ablation, osteoplasty, reinforcement, and internal fixation (AORIF) is a technique for treating and stabilizing osteolytic bone metastases. The procedure incorporates radiofrequency ablation for cancer treatment with PMMA cement and internal screw fixation for stabilization. This minimally invasive percutaneous approach aims to provide therapy, pain relief, and stability, while avoiding the risk associated with radiation and open surgery.

This study included 23 patients with 26 consecutive symptomatic osteolytic metastases who were treated with AORIF. Three patients had more than one treatment location. Lesions were located in the pelvis, proximal femur, proximal tibia, and calcaneus. AORIF was performed using cone beam CT guidance for 21 lesions and fluoroscopic guidance for 6 lesions. Post procedural pain and function, follow up imaging, and complications were evaluated.

No complications were described with the initial wire placement, screw placement, or ablation. Two balloons ruptured, which were retrieved without further complication. There was one instance of PMMA extravasation without further related complication. No intra or post procedural blood transfusion was required. No infection, wound complication, fracture or hardware complication was reported at 30 day follow up. No patient required a secondary or revision procedure during the follow-up period (1-18 months). All patients reported improved pain and function at 2 weeks post procedure.

Commentary


The authors evaluated 23 patients treated with AORIF for symptomatic lytic bone metastases. The results are impressive with all subjects experiencing improved pain and function, as well as zero postoperative complications, and no required secondary procedures during the follow-up period. While the cases of intraoperative balloon rupture and PMMA extravasation were inconsequential, they raise awareness for potential adverse events of the AORIF procedure. The study is limited by the small cohort, single center, and lack of control arm for comparison. Despite the limitations, the study demonstrates remarkable outcomes. The study highlights various benefits of AORIF including a spectrum of different anatomic applications and approaches. AORIF offers a low risk, minimally invasive surgical alternative for the management of lytic bone metastases. This study opens the door for future studies to further validate the AORIF procedure.

Post author
Maxwell R. Cretcher, DO
Resident Physician, Integrated Interventional Radiology
Dotter Department of Interventional Radiology
Oregon Health & Science University

Friday, May 1, 2020

Safety of Therapeutic Anticoagulation with Low-Molecular-Weight Heparin or Unfractionated Heparin Infusion during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism


Clinical question
Is there a significant difference in complication profile in use of therapeutic dosed low-molecular-weight heparin versus unfractionated heparin infusion during catheter directed thrombolysis?

Take-away point
No significant difference was found in complication rates between use of therapeutic dosed low-molecular-weight heparin and heparin infusion during catheter directed thrombolysis for acute pulmonary embolism

Reference
Assaf Graif et al. Safety of Therapeutic Anticoagulation with Low-Molecular-Weight Heparin or Unfractionated Heparin Infusion during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism. Journal of Vascular and Interventional Radiology. April, 2020: 31; 4, 537-543.

Click here for abstract

Study design
Retrospective Review

Funding source
Self-funded or unfunded

Setting
Single-center


Figure 3. Complications

Summary


Anticoagulation dosing during catheter directed thrombolysis for pulmonary embolism (PE) remains controversial with no clear consensus between cessation of systemic anticoagulation versus therapeutic dosing versus subtherapeutic dosing. Similarly, there is no clear data to differentiate use of low-molecular-weight heparin (LMWH) versus unfractionated heparin. This study aimed to evaluate safety of therapeutic-dose anticoagulation. With a focus on hemorrhagic complications, during catheter directed thrombolysis for acute pulmonary embolism.

156 patients were identified who underwent catheter directed thrombolysis for submassive of massive acute pulmonary embolism. All patients were treated with therapeutic anticoagulation, either unfractionated heparin infusion (ptt every 6 hours with target range of 50-80 seconds) or LMWH (weight based, BID 1 mg/kg) based on physician preference. Primary endpoints were hemorrhagic complications and all complications. No significant difference in hemorrhagic complication or all complications was found between heparin infusion and LMWH groups.

Commentary


Based on this study, there does not appear to be a significant difference in complication rate between therapeutic LMWH and heparin infusion during catheter directed thrombolysis for acute pulmonary embolism. The authors compared their complication rates to those of other studies using sub-therapeutic anticoagulation without major differences. While this may suggest no increased complication rate with use of therapeutic dosing, it does not prove any benefit either.

As is often the difficulty in retrospective reviews, there is significant heterogeneity in treatments performed. While the paper focused on heparin infusion versus LMWH, there was also significant variability in the catheter directed thrombolysis procedures (unilateral versus bilateral, infusion catheter choice, clot fragmentation, thrombectomy, plasty). Additionally, 5% of patients received systemic tPA prior to thrombolysis.

Further research is necessary in this realm, specifically comparing therapeutic dosing to subtherapeutic dosing of anticoagulation while minimizing heterogeneity between treatments.

Post Author
David M Mauro, MD
Assistant Professor
Department of Radiology, Vascular and Interventional Radiology
University of North Carolina

@DavidMauroMD

Friday, April 24, 2020

Cystic Duct Embolization with Chemical Gallbladder Ablation for the Treatment of Acute Calculous Cholecystitis in High-Risk Patients: A Prospective Single-Center Study


Clinical question

Can cystic duct embolization followed by chemical gallbladder ablation provide an alternative to permanent external drainage for non-surgical patients with calculous cholecystitis?

Take-away point
In non-surgical patients with calculous cholecystitis treated with permanent external drainage, coil cystic duct embolization followed by chemical ablation with a sclerosing agent can facilitate eventual catheter removal.

Reference

Atar E, Khasminsky V, Friehmann T, Choen A, Bachar GN. Cystic Duct Embolization with Chemical Gallbladder Ablation for the Treatment of Acute Calculous Cholecystitis in High-Risk Patients: A Prospective Single-Center Study. J Vasc Interv Radiology. 2020; 31:644-648

Click here for abstract

Study design
Single Arm, Prospective Cohort study

Funding
No reported Funding

Setting
Single Center, Academic Hospital. Rabin Medical Center, Tel Aviv University, Israel






Figure. An 80-year-old man with acute calculous cholecystitis who was ineligible for surgery because of severe comorbidities. (a) Cholangiography via the gallbladder drain demonstrates gallstones in the gallbladder but not in the common bile duct (arrow). (b) The cystic duct is blocked by means of Nester coils (arrow). (c) Gallbladder ablation is performed via the gallbladder drainage tube tract (arrow). (d) On fuoroscopy performed after 1 month, the gallbladder is still shrunken (arrow), and the drain is removed. (e) On ultrasound performed after 3 months, the gallbladder is shrunken and filled with stones (arrow).

Summary


Standard treatment for calculous cholecystitis is surgical cholecystectomy, however in elderly patients with high risk comorbidities there is increased morbidity and mortality after cholecystectomy. Percutaneous cholecystostomy provides a bridge or definitive therapy, however, eventual tube removal is associated with recurrent cholecystitis and prolonged percutaneous drainage requires follow-up maintenance procedures and is associated with decreased quality of life.

In this study, the authors demonstrate that following percutaneous cholecystostomy tube placement, cystic duct embolization followed by chemical gallbladder ablation is a viable alternative to definitive external drainage. 10 non-surgical patients were enrolled and underwent urgent cholecystostomy tube placement for acute cholecystitis. Nine (9) of the patients proceeded to have cholangiography via the external drain with any biliary duct stones successfully pushed into duodenum. A 10-Fr multipurpose drainage catheter was left in place, bridging the cystic duct to the duodenum to avoid future cannulation of cystic duct. After an asymptomatic interval period of 2-3 weeks, patients were considered for cystic duct coil embolization. A capped external drain was left in gallbladder with the option of drainage for symptomatic patients. After an additional asymptomatic interval of 3 weeks, cystic duct occlusion was confirmed with cholangiography followed by chemical gallbladder ablation with 3% aethoxysklerol. Interval sonography 3 weeks following this was performed to confirm gallbladder collapse (<25mm) and pericholecystic fluid absence. External drains were removed if asymptomatic. If gallbladder was >25mm, patient kept external drain for another 3 weeks with periodic sonography.

9 of 10 patients successfully proceeded with the full series of drainage, embolization, and ablation. After coil embolization, cholangiography on patient 1 demonstrated contrast spillage along the drain with transcolonic passage of contrast. This patient was initially planned for subsequent ablation, however the gallbladder remained non-dilated and the patient asymptomatic so no additional intervention was performed. Patient 2 experienced coil migration (4mm-5mm diameter) into the common bile duct. The coil was snared and replaced with a larger-caliber coil (8 mm). Patient 3 had undergone prior cystic duct embolization and gallbladder ablation, that resulted with subcutaneous leaks at previous the access site. Repeat cholangiography demonstrated intact cystic duct embolization and the patient requested repeat chemical ablation, which was successful. Patient 8 had continuous gallbladder secretions despite multiple ablations. A drain was left in place until secretions ceased and the drain was eventually removed. The patient was asymptomatic for 9 months.

Sonography was performed at 1 month after external drain removal for all patients. Patients were followed by their own surgeons or family physicians with return to Vascular Radiology only if needed. 3 of the 10 patients were reported as deceased during the follow up period due to unrelated causes with minimum follow up time of 7 months.

Commentary


Non-surgical patients with cholecystotomy tubes in place have decreased quality of life and require, at minimum, interval procedures for routine catheter maintenance. This paper introduces the concept of a “percutaneous cholecystectomy” via cystic duct embolization followed by chemical gallbladder ablation. None of the patients experienced short or long-term complications; however, several patients had persistent external bilious drainage up to 14 months after the procedure. So while technically feasible, the procedure requires further refinement and comparison to other methods of ablation. 

Post authors
Lucas Fass, BS - Rush Medical College 2021 MD Candidate
Lucas_fass@rush.edu

Joshua Okero, BS - Rush Medical College 2023 MD Candidate 

David M Tabriz
Assistant Professor
Department of Vascular & Interventional Radiology
Rush University Medical Center, Chicago, IL
@DrDaveTabriz

Friday, April 17, 2020

Radiofrequency Ablation of Facial Venolymphatic Malformations: Assessment of Efficacy and Safety and the Role of Injectable Electrodes


Clinical questions

Is ultrasound-guided radiofrequency ablation safe and effective in treating facial microcystic lymphatic and venolymphatic malformations; and how does safety and efficacy compare when using a newer injectable electrode with induced-paralysis technique versus a standard noninjectable electrode?

Take-away point
US-guided RF ablation is effective and safe in the treatment of facial microcystic lymphatic and venolymphatic malformations. The induced-paralysis technique with an injectable electrode demonstrated noninferior safety and efficacy compared to noninjectable alternatives.


Reference
Cho, Se Jin. et al. Radiofrequency Ablation of Facial Venolymphatic Malformations: Assessment of Efficacy and Safety and the Role of Injectable Electrodes. Journal of Vascular and Interventional Radiology, Volume 31, Issue 4, 544 - 550.

Click here for abstract

Study design
Retrospective chart review

Funding source
Self-funded or unfunded 

Setting
Single-center



























Figure 2. Images from a 19-year-old woman with a mixed VLM. (a,b) Coronal contrast-enhanced CT (a) and fat-suppressed T2-weighted MR (b) images demonstrate a mixed VLM at the right sublingual and submandibular spaces. Note that the lesion is located close to the lower edge of the mandibular body, which is the location of the marginal mandibular branch of the facial nerve. (c) US image during RF ablation depicts the lesion (arrows) with an injectable electrode positioned at the center. (d) Coronal fat-suppressed T2-weighted image shows that the lesion is markedly decreased (volume reduction ratio, 79%) 11 months after a single-session ablation, without any complications.

Summary


Facial venolympathic malformations (VLMs) located in the head and neck can cause significant cosmetic disfigurement. Treatment has classically been accomplished with surgery, which can lead to scarring and neurovascular injury, ultimately leading to unsatisfying resolution. Ablation with sclerosing agent, however, has risen as an alternative therapy with investigations showing favorable efficacy. There is inadequate evidence of its utility in the treatment of microcystic lymphatic malformations (mLMs) and mixed VLMs, however, as sclerosing agent has not been shown to reduce mLM volume. RF ablation has been studied in mLM treatment with efficacy and safety, but the potential risk of thermal damage to functional nerve structures (e.g. cranial nerve branches) still exists. The authors proposed a novel technique for RF ablation for facial mLMs called “induced paralysis.” Using a novel electrode with multiple side holes at the non-insulated tip, the proceduralist can identify small motor and/or sensory nerves by injecting local anesthetic to the area around the tip prior to RF ablation, preventing inadvertent nerve damage.

In this retrospective chart review, 15 patients who had undergone RF ablation of a symptomatic facial VLM with ultrasound guidance within a 3-year period were identified. The group consisted of 3 males and a median age of 29 years. 6 patients were treated with the injectable electrode, while the remaining 9 were treated with the standard non-injectable electrode. The median number of treatments per patient was 1 (1-2 treatments). Median follow-up was 10 months (1-44 months). All patients underwent an initial cosmetic grading score (CGS) assessment as well as ultrasound and contrast-enhanced CT or MR imaging for initial volume assessment. Follow-up metrics included volume at 1 and 3 months with ultrasound and 6-month volume with CT or MRI. CGS and complications were also collected. Complete improvement was defined with a change of CGS from 4 to 1, whereas partial improvement was defined as a CGS of 4 to 2-4. Immediate and delayed procedure-related complications, including burns, bleeding, infection, necrosis, or sensory/motor nerve symptoms, parotid duct injury, and vascular damage were assessed with ultrasound.

Median CGS at final follow-up was 1 in all patients. This was not significantly different between injectable and noninjectable groups. 2 of 9 patients (22%) treated with the non-injectable probe experienced partial improvement versus 5 of 6 patients (83.3%) in the injectable probe group. Median volume decrease was 81% in the 13 patients with follow-up volume data. There was no significant difference between outcomes between non-injectable and injectable electrode groups despite similar incidence of a functional structure near the lesion on pre-procedure imaging (p<0.05). There was, however, a significant difference in outcomes between patients who had a nearby functional structure on imaging versus those without (p<0.05).

Two cases of nerve injury with partial improvement occurred in patients treated with the noninjectable electrode (22%). Specifically, 1 case of facial palsy with mild reduction of function (House-Brackmann grade II) and 1 case of hypoesthesia secondary to submental nerve injury were reported. Both of these patients experienced partial improvement of nerve injury symptoms. 1 case of intermittent sharp pain near the ablation zone was reported in a patient treated with the injectable probe (16.7%) which subsided after 1 month.

Commentary


This study confirms previous findings demonstrating the efficacy of US-guided RF ablation of facial VLMs and mLMs. It also suggests non-inferiority of the induced-paralysis technique with an injectable RF ablation probe to avoid nerve injury. RF ablation therapy has shown significant potential as a safe and effective alternative to surgical therapy for facial vascular lesions, and is specifically associated with lesion volume reduction of mLMs while chemical ablation is not. The study is limited by its small sample size, discrepancy in lesion volumes between groups, retrospective design, and selection bias. These make the results inconclusive on their own. Future studies will be needed with larger patient groups in order to reduce heterogeneity of the study population and confirm the true potential of these modalities.

Post Author
Jared Edwards
4th Year Medical Student
Oregon Health & Science University School of Medicine, Portland, OR