Mechanical aspiration thrombectomy for the treatment of pulmonary embolism: A systematic review and meta-analysis.

INTRODUCTION: There are no randomized trials studying the outcomes of mechanical aspiration thrombectomy (MAT) for management of pulmonary embolism (PE). METHODS: We performed a systematic review and meta-analysis of existing literature to evaluate the safety and efficacy of MAT in the setting of PE. Inclusion criteria were as follows: studies reporting more than five patients, study involved MAT, and reported clinical outcomes and pulmonary artery pressures. Studies were excluded if they failed to separate thrombectomy data from catheter-directed thrombolysis data. Databases searched include PubMed, EMBASE, Web of Science until April, 2021. RESULTS: Fourteen case series were identified, consisting of 516 total patients (mean age 58.4 ± 13.6 years). Three studies had only high-risk PE, two studies had only intermediate-risk PE, and the remaining nine studies had a combination of both high-risk and intermediate-risk PE. Six studies used the Inari FlowTriever device, five studies used the Indigo Aspiration system, and the remaining three studies used the Rotarex or Aspirex suction thrombectomy system. Four total studies employed thrombolytics in a patient-specific manner, with seven receiving local lysis and 17 receiving systemic lysis, and 40 receiving both. A random-effects meta-analyses of proportions of in-hospital mortality, major bleeding, technical success, and clinical success were calculated, which yielded estimate pooled percentages [95% CI] of 3.6% [0.7%, 7.9%], 0.5% [0.0%, 1.8%], 97.1% [94.8%, 98.4%], and 90.7% [85.5%, 94.3%]. CONCLUSION: There is significant heterogeneity in clinical, physiologic, and angiographic data in the currently available data on MAT. RCTs with consistent parameters and outcomes measures are still needed.

Animal Models of Hepatocellular Carcinoma for Local-Regional Intraarterial Therapies.

Animal models play a crucial role in developing and testing new therapies for hepatocellular carcinoma (HCC), providing preclinical evidence prior to exploring human safety and efficacy outcomes. The interventional radiologist must weigh the advantages and disadvantages of various animal models available when testing a new local-regional therapy. This review highlights the currently available animal models for testing local-regional therapies for HCC and details the importance of considering animal genetics, tumor biology, and molecular mechanisms when ultimately choosing an animal model. Keywords: Animal Studies, Interventional-Vascular, Molecular Imaging-Clinical Translation, Molecular Imaging-Cancer, Chemoembolization, Liver © RSNA, 2022.

Surgical and endovascular repair for type B aortic dissections with mesenteric malperfusion syndrome: A systematic review of in-hospital mortality.

Objectives: Mesenteric malperfusion is a feared complication of aortic dissection, with high mortality. The purpose of this study was to systematically review in-hospital mortality (IHM) of endovascular and surgical management of acute and chronic Stanford type B aortic dissections (TBAD) complicated by mesenteric malperfusion (MesMP). Methods: A systematic search of English language articles was conducted in relevant databases. Data on patient demographics, procedure details, and survival outcomes were collected. Reports were classified by type of intervention performed. Studies that failed to report patient-level outcomes based on specific intervention performed or IHM were excluded. Retrospective chart review of previously published data from a single institution was also performed to further identify cases of TBAD that were managed endovascularly. The Fisher exact test was performed to determine statistical significance. Results: In total, 37 articles were suitable for inclusion in this systematic review, which yielded 149 patients with a median age 55.0 years (interquartile range, 46.5-65 years) and 79% being male. Overall, in-hospital mortality was 12.8% (19/149) and was similar between endovascular and open surgical interventions (13% vs 11%, P = .99). Among endovascular strategies, IHM was greater, although not statistically significant in the thoracic endovascular aortic repair group compared with the fenestration/stenting without thoracic endovascular aortic repair group (24% vs 11%, P = .15). Conclusions: Multiple strategies exist for the management of TBAD with MesMP; however, a majority of cases were managed endovascularly. Despite advances in therapies, mortality remains high at 13%.

Preoperative embolization of renal cell carcinoma prior to partial nephrectomy: A systematic review and meta-analysis.

PURPOSE: To evaluate the safety and efficacy of preoperative renal artery embolization of renal cell carcinoma in reducing intraoperative blood loss during subsequent partial nephrectomy through a systematic review and meta-analysis of current literature. MATERIALS AND METHODS: The PubMed database was searched for articles published from 1970 to 2018 describing patients with renal cell carcinoma who underwent partial nephrectomy with and without preoperative embolization of the tumor. Demographic data, procedural techniques, and surgical outcomes were obtained when available. A random-effects meta-analysis was performed to determine estimated blood loss in both groups of patients. RESULTS: The literature search identified 14 relevant articles for systematic review, of which 4 articles provided sufficient data to be included in the meta-analysis. 270 patients (173 males, 97 females) underwent partial nephrectomy for RCC, of whom 222 received pre-operative embolization. There were 48 patients in our cohort that underwent partial nephrectomy for RCC without preoperative embolization. Random-effects meta-analysis demonstrated a significant difference between EBL in patients undergoing RAE prior to partial nephrectomy vs partial nephrectomy without preoperative embolization, with EBL of 154.0 ± 22.6 mL (n = 222) and 353.4 ± 69.6 mL (n = 478), respectively (p < 0.0001). Major complications occurred in 4.9% of patients undergoing pre-operative embolization followed by partial nephrectomy, whereas major complications occurred in 10.9% of patients undergoing partial nephrectomy without embolization (p = 0.01). Minor complications occurred in 5.8% of patients undergoing embolization and partial nephrectomy and in 19.0% of patients undergoing partial nephrectomy without embolization (p < 0.0001). CONCLUSION: Renal artery embolization prior to surgical resection of renal cell carcinoma is safe and significantly reduces intraoperative blood loss in patients undergoing partial nephrectomy.

Perioperative blood loss after embolization of hypervascular musculoskeletal tumors outside of the spine: A single-center ten year experience and systematic review of the literature.

PURPOSE: To evaluate outcomes following trans-arterial embolization of hypervascular appendicular bony tumors in patients undergoing orthopedic resection by performing a systematic review including data from the authors' institution. MATERIALS AND METHODS: From April 2008 to August 2018, 73 patients (59 males, mean age 58.1 years) with musculoskeletal tumors presented for embolization for preoperative devascularization prior to orthopedic surgery. A retrospective chart review was performed to identify demographic, procedural and surgical data. A systematic review of the Pubmed, Medline, and Web of Science databases was performed to identify studies in which pre-operative embolization was performed of appendicular MSK tumors, and with measurements of estimated blood loss. All the variables listed above were recorded. A patient level analysis was performed to determine average estimated blood loss. RESULTS: 58 patients (47 men, 11 women, range 21-84 years) were included in our institutional analysis. The median EBL was 500 mL (range 100-3000). There was no difference in EBL between RCC (719.6 ± 626.1) and non-RCC groups (855.6 ± 657.5); p = 0.44. The median intra-operative transfusion requirement was 1.0 unit (range 0-8 ± 2.06). From 1984 to 2015, 9 studies were identified that provided data for a total of 118 patients (46 males, 42 females, range 10-82 years). The mean and median post-surgical EBL across all patients was 976.9 ± 78.5 (SE) and 725 mL (range 10-7000), respectively. There were no complications related to non-target embolization. CONCLUSION: Preoperative trans-arterial embolization of hypervascular MSK neoplasms appears to be safe and effective in minimizing peri- and post-operative bleeding while keeping transfusion requirements low.

Safety and Efficacy of Endovascular Treatment of Portal Vein Stenosis in Liver Transplant Recipients: A Systematic Review.

PURPOSE: To evaluate the efficacy of Angioplasty and Stent Placement for the treatment of Portal Vein Stenosis in Liver Transplant Recipients by performing a systematic review. MATERIALS AND METHODS: The PubMed Database was extensively searched for articles describing Portal Vein Stenosis (PVS) as a complication in Liver Transplant (LT) patients. The initial database search yielded 488 unique records published in the PubMed Database, 19 of which were deemed to meet the inclusion criteria. Outcomes were separated into 2 groups (Group A included patients with primary angioplasty, Group B included patients with primary stent placement), and further subdivided into Adult and Pediatric populations. RESULTS: Group A included a total of 282 LT patients with portal vein stenosis. The population was predominantly pediatric (n = 243). Group B included a total of 111 LT patients with portal vein stenosis. This population was predominantly adult (n = 66). Technical success was significantly higher in both Group B pediatric (100%) and adults (97%) compared to Group A (69.5%) and (66.7%) respectively. Re-stenosis rates were significantly lower in Group B pediatric group compared to Group A (2.3% vs 29.7%, χ2 = 13.9; p < 0.001). Overall major (3.1%) and minor complications rates (1.5%) were low. CONCLUSION: Primary stent placement appears to have higher technical success in both populations and lower re-stenosis rates for treatment of PVS in pediatric populations.

Expedited TR Band Removal for Transradial Approach for Noncoronary Visceral Procedures: Initial Experience.

PURPOSE: For transradial interventions, most published studies report an initial Terumo Radial (TR) band placement time of 60 minutes, with gradual deflation over 30 to 90 minutes. We aimed to determine, retrospectively, whether TR band removal time could be expedited to 45 to 60 minutes, without adverse effects via an expedited single-step deflation protocol. METHODS: A total of 115 consecutive noncoronary visceral interventions that utilized TR band from September 2017 till February 2019 were retrospectively reviewed. Alternative single-step deflation protocol was utilized where the nursing staff was instructed to deflate the TR band in 1 step between 45 and 60 minutes; 79 patients (43 men, 36 women, mean age of 55.3 ± 13.6 years) underwent 115 transradial interventions. Mean procedure time was 49.8 ± 22.1 minutes, and mean fluoroscopy time was 18.5 ± 10.6 minutes. Data collected included patient demographics, procedure details, and nursing notes on complications including bleeding and reinflation of the TR band. Univariate and Multivariate analyses of independent variables were performed using a binary logistic regression model. All patients were followed up postoperatively before discharge and in clinic upon follow-up. RESULTS: The TR band was deflated at 51.3 ± 14.5 minutes, with successful removal achieved on the first attempt in 103 cases (90.3% primary technical success rate). In 12 cases, bleeding was noted upon initial deflation, secondary technical success was achieved when the band was reinflated for an additional mean time of 37.0 ± 19.1 minutes. There was 1 incidence of radial artery occlusion (0.8%) and 1 incidence of a grade 1 hematoma (0.8%). The only variable predictive of technical outcome upon initial band deflation on univariate binomial logistic regression was initial TR band removal time (P = .019). CONCLUSIONS: A single-step deflation protocol for TR band placement may be safe for nonocclusive patent hemostasis and may translate to even further shorten postprocedural hospital times for patients and cost savings for hospitals.

Endovascular Management of Hemarthrosis in Patients with Bleeding Diatheses: Systematic Review.

PURPOSE: In this systematic review, we report the safety and efficacy of embolization for treating hemarthrosis in patients with bleeding diatheses with or without a history of prior arthroplasty. MATERIALS AND METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. A structured search was performed in PubMed, Web of Science, MEDLINE, and SCOPUS databases of patients undergoing embolization for hemarthrosis. Demographic data, clinical history, angiographic findings, interventions, and outcomes were extracted and tabulated. RESULTS: The search identified 97 unique titles of which 15 were deemed relevant comprising 78 patients with coagulopathies undergoing 93 embolization procedures. Mean follow-up time was 29 months (range 3-116.5). In the 29 patients who underwent arthroplasty prior to embolization for hemarthrosis, there were 11 bleeding recurrences (37.9%). Of these patients who experienced recurrences, 10 underwent repeat embolization as coagulation factor replacement was not sufficient to address the re-bleeding. In the 49 patients with bleeding diatheses who underwent embolization for hemarthrosis with no history of prior arthroplasty, there were 11 recurrences (22.4%) and 4 of these patients underwent repeat embolization with favorable results. There were four major procedure-related complications. CONCLUSION: Transarterial embolization is safe and effective in addressing recurrent hemarthrosis in patients with bleeding diatheses with or without a history of arthroplasty of the affected joint.

Safety and Efficacy of Sacroplasty for Sacral Fractures: A Systematic Review and Meta-Analysis.

PURPOSE: To evaluate the safety and efficacy of sacroplasty for the treatment of osteoporotic and malignant sacral fractures by performing a systematic review and meta-analysis of existing literature. MATERIALS AND METHODS: PubMed, Web of Science, and SCOPUS databases were searched from their inception until February 2018 for articles describing sacroplasty. Inclusion criteria were as follows: studies reporting > 5 patients, and pain assessment before and after the procedure recorded with visual analog scale (VAS). Demographic data, procedural details, technical success rates, VAS scores before and after the procedure, and procedural complications were recorded. A random-effects meta-analyses of the VAS pain score before the procedure, at 24-48 hours, at 6 months, and at 12 months were calculated. RESULTS: Nineteen studies (18 case series and 1 cohort study) were identified consisting of 861 total patients (682 women and 167 men; mean age 73.89 ± 9.73 years). Patients underwent sacroplasty for the following indications: sacral insufficiency fractures secondary to osteoporosis (n = 664), malignancy (n = 167), and nonspecified sacral insufficiency fractures (n = 30). Technical and clinical successes were achieved in 98.9% (852/861) and 95.7% (623/651) of patients undergoing sacroplasty, respectively. The pooled major complication rate was 0.3%, with 3 patients requiring surgical decompression for cement leakage. Random-effects meta-analyses demonstrated statistically significant differences in the VAS pain level at preprocedure, 24-48 hours, 6 months, and 12 months, with cumulative pain scores of 8.32 ± 0.01, 3.55 ± 0.01, 1.48 ± 0.01, and 0.923 ± 0.01, respectively. CONCLUSIONS: Sacroplasty appears safe and effective for pain relief in patients with osteoporotic or malignant sacral fractures, with statistically significant sustained improvement in VAS pain scores up to 12 months.

Single-molecule analysis reveals multi-state folding of a guanine riboswitch.

Guanine-responsive riboswitches undergo ligand-dependent structural rearrangements to control gene expression by transcription termination. While the molecular basis for ligand recognition is well established, the associated structural rearrangements and the kinetics involved in the formation of the aptamer domain are less well understood. Using high-resolution optical tweezers, we followed the folding trajectories of a single molecule of the xpt-pbuX guanine aptamer from Bacillus subtilis. We report a rapid six-state conformational rearrangement, in which three of the states are guanine dependent, during the transition from the linear to the native receptor conformation. The folding completes in <1 s. The force-dependent equilibrium kinetics and the mutational data indicated that the flexible J2-J3 junction undergoes a ligand-dependent conformational switching, which triggers the formation of the long-range tertiary interactions and the P1 helix. In the absence of the right ligand, the junction failed to initiate the series of conformational rearrangements required for the riboswitch activities.

Distinguishing ventricular arrhythmia originating from the right coronary cusp, peripulmonic valve area, and the right ventricular outflow tract: utility of lead I.

INTRODUCTION: Outflow tract ventricular arrhythmia (OTVA) can be complicated to target for ablation when originating from either the periaortic or pulmonary valve (PV) region. Both sites may present with a small R wave in lead V1. However, the utility of lead I in distinguishing these arrhythmia locations is unknown. METHODS AND RESULTS: Thirty-six consecutive patients (mean age 41 ± 14 years, 13 male) underwent catheter ablation for OTVA. OTVA origin was determined from intracardiac electrogram tracings and electroanatomic maps. Observers blinded to results measured QRS waveform amplitude and duration from standard 12-lead ECG tracings. Measurements with highest diagnostic performance were modeled into an algorithm. Sites of successful ablation were anterior right ventricular outflow tract (RVOT; n = 6), posterior RVOT (n = 4), PV (n = 18), and right coronary cusp (RCC; n = 8). Highest performing surface ECG discriminators were from lead I to V1 vectors: RCC, lead I R wave ≥ 1.5 mV, and V1 R wave ≥2.0 mV (sensitivity 87%, specificity 93%); PV, V1 R wave > 0 mV, and lead I R/(R+S) ≤ 0.75 (sensitivity 78%, specificity 72%); anterior RVOT, V1 R wave = 0 mV, and lead I R/(R+S) <0.4 (sensitivity 67%, specificity 97%); posterior RVOT, V1 R wave > 0 mV, and lead I R/(R+S) > 0.75 (sensitivity 75%, specificity 84%). Sequential algorithmic application of these criteria resulted in an overall accuracy of 72% in predicting site of OTVA origin. CONCLUSIONS: A relatively large R wave in lead I is seen with RCC origin but not PV origin. A sequential algorithm has limited but potentially significant value beyond assessment of lead I in approaching OTVA.

Implanted endocardial lead characteristics and risk of stroke or transient ischemic attack.

INTRODUCTION: Patent foramen ovale (PFO) has been recently implicated as a strong predictor of stroke or transient ischemic attack (TIA) in patients with implanted pacemaker or defibrillation leads. Leads in the right heart can form thrombi that embolize to the pulmonary circulation and raise pulmonary pressure. This increases right-to-left shunting through PFO or intrapulmonary shunts and can result in paradoxical embolism. We sought to determine whether certain lead characteristics confer a higher thrombogenic risk resulting in stroke/TIAs in patients either with or without a PFO. METHODS: We retrospectively analyzed 5,646 patients (mean age 67.3 ± 16.3 years, 64 % male) who had endocardial device leads implanted in 2000-2010. We performed univariate and multivariate-adjusted proportional hazards models to determine association of lead characteristics with stroke/TIA during follow-up. RESULTS: On univariate analysis, passively fixated tined leads were associated with more stroke/TIAs (HR 1.77, 95 % CI 1.27, 2.47; p<0.001), whereas presence of defibrillation coil was associated with fewer stroke/TIAs (HR 0.59, 95 % CI 0.42-0.84; p=0.003). Number of leads per patient, presence of atrial lead, maximum lead size, tip shape, and type of insulating material were not associated with stoke/TIA. On multivariate analyses adjusting for age, sex, diagnosis of PFO, and prior history of stroke/TIA, the presence of tined leads was associated with stroke/TIA (HR 1.41, 95 % CI 1.00-1.97; p=0.049). Defibrillation coils were no longer associated with lower stroke/TIA on multivariate analysis. CONCLUSIONS: Most physical characteristics of contemporary leads do not impact rate of stroke/TIA among patients receiving implantable devices. The presence of a PFO is a major risk factor for stroke/TIA in patients with endovascular leads.