Midterm outcomes of arteriovenous fistula aneurysm repair with simultaneous inflow revision or outflow tract revascularization.

OBJECTIVE: The aim of this study was to investigate the 2-year outcomes of extensive revisions aimed at simultaneously addressing arteriovenous fistula (AVF) aneurysms, outflow stenosis, and/or high flow volumes. METHODS: This was a retrospective cohort study in a tertiary referral center. The study population comprised hemodialysis patients with aneurysmal AVFs requiring revision. Subjects were eligible if they were ≥18 years of age and had aneurysm repair associated with inflow revision or treatment of outflow lesions. Patients were followed-up for a minimum of 2 years, and the primary outcome measure was cumulative patency. RESULTS: Our cohort comprised 93 patients with a mean age of 56 ± 12 years. The most frequent access type was brachiocephalic fistula (61%), and the median access age at the time of revision was 66 months (interquartile range, 46-93 months). The median access flow volume was 2300 ml/min (interquartile range, 1281-2900), and 31 subjects (33%) presented aneurysms associated with both high flow and venous obstruction. Aneurysm repair consisted of aneurysmorraphy in the overwhelming majority (95%). Inflow revision was performed in a total of 49 cases (53%), and outflow tract obstruction was treated in 71 patients (72%), with 27 patients (29%) receiving a simultaneous 3-component revision. At 2 years, the primary, primary assisted, and cumulative patencies were 60% ± 1%, 91% ± 3%, and 94% ± 3%, respectively. The most frequent indication for first-time reinterventions was outflow tract stenosis (24%). Aneurysm recurrence was observed in 13 subjects (14%) during the entire follow-up and was responsible for reinterventions in seven of them (8%), with a 2-year freedom from aneurysm-related reintervention rate of 95% ± 3%. CONCLUSIONS: Extensive AVF revision with simultaneous aneurysm repair, inflow revision, and outflow tract revascularization is feasible, safe, and associated with favorable 2-year patency rates.

Internal mammary artery injury complicating a Surfacer inside-out central venous catheterization.

We report the case of a near fatal arterial injury in a patient undergoing an inside-out catheter placement through an occluded central venous system using the Surfacer device (Bluegrass Vascular). The right internal mammary artery was inadvertently lacerated during the procedure, leading to cardiovascular collapse. The patient was rescued by transfusion, placement of a chest tube, and coil embolization of the right internal mammary artery. Postprocedure analysis of intraoperative cone beam computed tomography revealed that this injury was predictable on imaging, underscoring the need for advanced imaging guidance to enhance the safety of this procedure.

Stem Cell Therapy: A Possible Role in the Treatment of Patients with Chronic Limb-Threatening Ischemia?

Chronic limb-threatening ischemia (CLTI) is a severe form of peripheral arterial disease that portends high morbidity and mortality. Patients may undergo various endovascular or open procedures with the goal of limb salvage. No-option CLTI patients represent a vulnerable population for whom conventional options have been exhausted, or anatomy precludes any attempts at revascularization, often resulting in amputation. Stem cell therapy is under investigation for these no-option CLTI patients. Regardless of revascularization technique, these patients are clinically challenging and require multidisciplinary efforts to achieve the best outcomes. Here we present a patient with unfavorable anatomy who underwent stem cell therapy injection for a nonhealing right first toe wound, and we include points to remember when considering stem cell treatment in patients with CLTI.

Safety of bilateral arm pressure measurements in the diagnostic workup of dialysis-associated steal syndrome.

OBJECTIVE: Although bilateral brachial pressure measurement is routinely included in the diagnostic work-up of upper extremity ischemia, it is generally avoided in the presence of hemodialysis access due to fears of inducing access thrombosis. This study evaluated the safety of bilateral brachial pressure measurement in patients with clinical suspicion of dialysis-associated steal syndrome (DASS). METHODS: Patients undergoing non-invasive testing for steal syndrome between September 2015 and December 2021 were included in this study. The diagnostic workup was performed by certified vascular sonographers in an outpatient vascular lab and consisted of bilateral brachial pressures, photoplethysmography, and duplex ultrasonography of the access. Interarm differential (IAD) was defined as systolic blood pressure (SBP) in the contralateral arm minus SBP in the access arm. The primary endpoint was immediate access thrombosis. RESULTS: The study sample consisted of 331 subjects with a mean age of 61 ± 13 and a median access age of 9 months (3-31 months) with radiocephalic fistulas present in 29%. Many patients (68%) presented with paresthesia and 4% presented with tissue loss. The mean brachial systolic pressure was 152 ± 37 mmHg on the ipsilateral arm versus 143 ± 34 mmHg on the contralateral (p-value <0.001), with an inter-arm differential (IAD) of -8.4 ± 19 mmHg. A total of 16 subjects (5%) presented a differential ⩾20 mmHg. A positive thrill was noted in all the accesses immediately following blood pressure measurement and no occurrence of access thrombosis was noted at 30 days. Proximal arterial revascularization interventions were performed in 11 cases (3%). Subjects who presented an IAD ⩾20 mmHg had lower ipsilateral digital-brachial index (0.39 ± 0.18 vs 0.68 ± 0.26; p = 0.037), a higher tendency of being referred for angiograms (37.5% vs 10.5%, p = 0.006), and more proximal arterial revascularization procedures (25.0% vs 2.2%, p = 0.001). CONCLUSION: Bilateral arm pressure measurement in the context of dialysis access-associated steal syndrome (DASS) appears safe and useful for identifying subjects whose symptoms are due to proximal arterial inflow disease. We therefore recommend this test be considered in the diagnostic algorithms of DASS.

Cadaveric aortic aneurysm creation: A life-like model for training endovascular repair.

The recent decline in RAAA incidence and the fast paced scenario with associated challenges regarding training calls for initiative for a better training environment to maximize learning. This led us to the creation of a pulsatile human cadaveric RAAA model. Fresh frozen cadaver was used to create RAAA with BioTissue in hybrid suite with ability to perform CBCTA for sizing. As a proof of concept, the model was used to perform REVAR with proximal CODA balloon control. The model proved to be feasible and we believe it is a better environment to train and gain adequate proficiency in RAAA management.

Scoping review of atherectomy and intravascular lithotripsy with or without balloon angioplasty in below-the-knee lesions.

Objective: We evaluated how contemporary data on infrapopliteal vessel preparation have been reported to identify knowledge gaps and opportunities for future research. Methods: A literature search was performed on Web of Science, PubMed, and Google Scholar to identify clinical research studies reporting on the outcomes of vessel preparation in below-the-knee lesions between 2006 and 2021. Studies were excluded if they were case reports or case series with a sample size of <10. Results: A total of 15 studies comprising 5450 patients were included in this review, with vessel preparation performed in 2179 cases (40%). Of the 15 studies, 2 were randomized controlled trials, 6 were prospective cohort studies, and 7 were retrospective studies. Only 2 of the 15 studies evaluated intravascular lithotripsy devices, and 6 were noncomparative studies. The mean diameter stenosis treated was 86.7% ± 12.6%, and the lesion length was 71.7 ± 55.3 mm. Large heterogeneity was found in the choice and definitions of end points and lesion characterization. Procedural success ranged between 84% and 90%, and bailout stenting was performed in 0.8% to 15% of cases. Of the five studies comparing procedural success of atherectomy with or without balloon angioplasty to balloon angioplasty alone, only one was in favor of the former (99% vs 90%; P < .001). The remaining studies did not show any statistically significant differences. Similarly, atherectomy had a significantly superior limb salvage rate in only one of seven studies (91% vs 73%; P = .036). In contrast, the seven studies evaluating target lesion revascularization reported conflicting outcomes, with two in favor of atherectomy, two against atherectomy, and three reporting similar outcomes between atherectomy and balloon angioplasty alone. None of the studies evaluating intravascular lithotripsy was comparative. Conclusions: The current body of evidence on vessel preparation in tibial arteries is largely based on observational studies with a large amount of heterogeneity and a number of inconsistencies. Further clinical and experimental studies with more robust study designs are warranted to investigate the comparative efficacy and safety of vessel preparation in calcified tibial arteries.

Cardiovascular collapse during mechanical thrombectomy for acute pulmonary embolism and the role of extracorporeal membrane oxygenation in patient rescue.

BACKGROUND: Driven by the ability to avoid thrombolytics and provide a one stop procedure with immediate hemodynamic improvement, there has been a dramatic increase in the use of mechanical thrombectomy (MT) devices for the treatment of intermediate-to-high risk pulmonary embolism (PE). This study investigated the incidence and outcomes of cardiovascular collapse during MT procedures and demonstrates the role of extracorporeal membrane oxygenation (ECMO) in salvaging patients. METHODS: This single-center retrospective review included patients with PE undergoing MT with the FlowTriever device between 2017 and 2022. Patients presenting periprocedural cardiac arrest were identified and their perioperative characteristics and postoperative outcomes were evaluated. RESULTS: A total of 151 patients with a mean age of 64 ± 14 years who presented with intermediate-to-high risk PE received LBAT procedures during the study period. The simplified PE severity score was ≥1 in 83% of cases and the average RV/LV ratio was 1.6 ± 0.5, with and elevated troponin in 84%. Technical success was achieved in 98.7% and a significant decrease in pulmonary artery systolic pressure (PASP) was observed (37 mm Hg vs 56 mm Hg; P < .0001). Intraoperative cardiac arrest occurred in nine patients (6%). These patients were more likely to present PASP of ≥70 mm Hg (84% vs 14%; P < .001), were more hypotensive upon admission (systolic of 94 ± 14 mm Hg vs 119 ± 23 mm Hg; P = .004), presented lower oxygen saturation levels (87 ± 6% vs 92 ± 6%; P = .023) and were more likely to present with a history of recent surgery (67% vs 18%; P = .004). Four patients were rescued successfully with ECMO and their residual PE was subsequently removed before discharge by surgical embolectomy in two of the four cases and repeat MT in the other two. All five patients (3%) who did not receive ECMO support expired intraoperatively. The overall 30-day mortality was 8% with no death occurring in patients who were salvaged with ECMO. CONCLUSIONS: Large-bore aspiration thrombectomy for acute PE is associated with favorable technical outcomes, but the concern for acute cardiac decompensation is non-negligible in patients presenting with high-risk features and a PASP of ≥70 mm Hg. ECMO can help to salvage some of these patients and should be considered in the treatment algorithms of patients deemed at high risk.

To Cross or Not to Cross: Using MRI-Histology to Characterize Dense Collagenous Plaque in Critical Limb Ischemia.

Peripheral artery disease (PAD) is caused by atherosclerotic buildup in the lower extremities, leading to obstruction and inadequate perfusion to the peripheral vasculature. Impenetrable plaques initially treated with percutaneous vascular intervention (PVI) have led to worse secondary bypass outcomes and amputation in patients. In this case report, we discuss the importance of using magnetic resonance imaging (MRI) histology in PVI planning in a patient with critical limb ischemia. PVI attempts to recanalize the limb failed because of an impenetrable occlusion in the popliteal artery that was not identified on routine preoperative imaging. Subsequent bypass occluded multiple times eventually requiring an above-knee amputation. An MRI-histology protocol-using ultrashort echo time (UTE) and T2-weighted (T2W) sequences-that was performed prior to the index PVI identified the occlusion as a dense collagen plaque. Histology analysis of the amputated specimen confirmed the MRI finding. This imaging modality offers a novel approach to characterize plaque composition and morphology, thereby identifying lesions at greatest risk of PVI failure and potentially playing an important role in selecting the right candidates for an endovascular-first approach.

A Single-Center Experience With Total Percutaneous Implantation of a Low-Profile Thoracic Aortic Stent-Graft.

PURPOSE: To evaluate the safety and effectiveness of total percutaneous implantation of the Zenith Alpha Thoracic (ZTA) endograft in the treatment of diseases of the descending thoracic aorta. MATERIALS AND METHODS: A retrospective cohort study of 56 consecutive patients undergoing total percutaneous ZTA implantation between 2018 and 2020 was performed in a single center. Patients' demographics, clinical characteristics, anatomical parameters, operative details, device features, and postoperative outcomes were assessed. The primary endpoint was ongoing clinical success. A Cox regression model was used to determine the predictive factors of worse postoperative outcomes. RESULTS: Eighty-three ZTA endografts were implanted in 35 men and 21 women with a mean age of 69±11 years for the treatment of 26 degenerative aneurysms, 15 type B dissections, and 8 penetrating ulcers, among others. Primary technical success was 100%, with a 30-day ongoing clinical success rate of 94.6%. The 1-year ongoing clinical success rate was 91.1% (51 patients), and freedoms from all-cause mortality, type 1 and 3 endoleaks, and any unplanned reintervention were, respectively, 95.3%, 91.4%, and 88.2% at 1 year. During follow-up, there was one case of surgical conversion for an aorto-esophageal fistula. On the contrary, neither aneurysmal rupture nor significant aneurysmal expansion was recorded. Repair of ruptured thoracic aorta and a high ratio of sheath outer diameter to external iliac artery diameter were found to be independently associated with worse outcomes, with adjusted odds ratios of 4.4 [1.5-15.3] and 4.9 [1.1-23.9], respectively. CONCLUSION: The outcomes of total percutaneous implantation of ZTA endograft show excellent primary technical success and favorable midterm ongoing clinical success. Factors associated with worse outcomes include the repair of ruptured aorta and a high sheath to access vessel ratio.

Human Cadaveric Model for Vessel Preparation Device Testing in Calcified Tibial Arteries.

To describe an ex vivo model for vessel preparation device testing in tibial arteries. We performed orbital atherectomy (OA), intravascular lithotripsy (IVL), and plain balloon angioplasty (POBA) on human amputated limbs with evidence of concentric tibial artery calcification. The arterial segments were then harvested for ex vivo processing which included imaging with microCT, decalcification, and histology. The model was tested out in 15 limbs and was successful in 14 but had to be aborted in 1/15 case due to inability to achieve wire access. A total of 22 lesions were treated with OA on 3/22 lesions, IVL on 8/22, and POBA without vessel preparation on the remaining 11/22. Luminal gain was assessed with intravascular ultrasound and histology was able to demonstrate plaque disruption, dissections, and cracks within the calcified lesions. A human cadaveric model using amputated limbs is a feasible, high-fidelity option for evaluating the performance of vessel preparation devices in calcified tibial arteries.

From bench to bedside: A narrative review and institutional experience with experimental models for vascular device design and translation.

The past 2 decades have seen a rise in vascular innovations and a rapid evolution in endovascular device technology, with the emergence of atherectomy, intravascular lithotripsy, drug elution technology, thrombectomy devices, and many more. Like all other medical devices, vascular devices undergo a life cycle composed of a concept phase, a planning and design phase, a regulatory process, a launch phase, and a post-market stage. Experimental and preclinical models are required at various stages of the life cycle to aid in the designing, refining, and feasibility testing of novel devices before they are transferred to clinical practice. The experimental testing of these devices relies heavily on the ability to simulate human anatomy and physiology, and to mimic or induce specific disease processes. Computational and benchtop models play very important roles at the early stages of the manufacturing process, and animal and cadaveric models are indispensable for testing the mechanistic performance, safety, and efficacy of novel devices before they are used in clinical trials and regulatory approval is obtained for public use.

Advanced intraoperative imaging guidance for inside-out central venous recanalization using a novel catheter access system.

BACKGROUND: The novel Surfacer Inside-Out recanalization technique facilitates right-sided central venous access in occluded vessels but carries a risk of arterial and pleural injuries. This article demonstrates how an advanced intraoperative imaging protocol can help to avoid these potential complications. METHODS: This retrospective review included patients undergoing the Surfacer Inside-Out central venous recanalization procedure between December 2017 and October 2021. The study sample comprised patients included in the SAVE-US trial at our site as well as patients treated after US Food and Drug Administration approval of the device. All procedures were performed using intraoperative cone-beam computed tomography (CBCT) angiography to map out the trajectory of the device through the mediastinum and supraclavicular space with fusion imaging for guidance. Procedures were aborted if CBCT findings predicted injury to arterial or respiratory structures. The intraoperative coronal and sagittal orientation of the device was compared to preoperatively predicted trajectory. RESULTS: A total of 17 procedures were performed in 16 patients with end-stage renal disease and a mean age of 61 ± 11 years. Most patients presented a type 3 central venous occlusion (9/15). Successful recanalization was achieved in 14 of the 17 cases (82.4%) with no intraoperative complications. The procedure had to be aborted in 3 of the 17 cases based on intraoperative CBCT findings, which projected the device to perforate the right pleural space in one patient, the trachea and right subclavian artery in another, and the innominate artery in the third patient. The total radiation dose per procedure was 753 ± 346 mGy and the mean procedural time was 101.6 ± 29.7 minutes. A median of 2 (range, 1-5) intraoperative CBCT scans were performed per patient and accounted for 70% of the total radiation dose. Statistical analysis showed intraoperative CBCT findings to differ significantly from preoperative predicted values. CONCLUSIONS: The nonsteerable and penetrating nature of the Surfacer device may lead to serious complications when performed under fluoroscopic guidance alone. Intraoperative CBCT with fusion overlay enhances the safety and effective use of this device and inside out crossing technique.

Postoperative Outcomes and Reinterventions Following Fenestrated/Branched Endovascular Aortic Repair in Post-Dissection and Complex Degenerative Abdominal and Thoraco-Abdominal Aortic Aneurysms.

BACKGROUND: The outcome of FBEVAR in post-dissection thoracoabdominal aortic aneurysms has not been well established in the literature. The aim of this study was to compare midterm outcomes following FBEVAR in post-dissection aneurysms to degenerative aneurysms. (2) Methods: This was a retrospective review of all patients undergoing FBEVAR in a single center between 2017 and 2020. The baseline characteristics, intraoperative details, and postoperative outcomes of patients with post-dissection aneurysms were compared to those with degenerative outcomes. The primary end point was unplanned reinterventions. Cox regression analysis was performed to identify the determinants of worse outcomes. RESULTS: A total of 137 subjects with a mean age of 70 ± 10 years were included in the study, out of which 30 presented post-dissection aneurysms (22%). Custom-made devices were employed in 119 patients, off-the-shelf devices in 13 and physician-modified endografts in 5, with incorporation in 505 target vessels. The technical success rate was comparable in both groups (97% vs. 98%, p = 0.21). However, the one-year freedom from unplanned reintervention was lower in the post-dissection group (67% vs. 89%, p = 0.011). CONCLUSION: FBEVAR in post-dissection aneurysms is associated with a favorable technical success rate, but reintervention rates remain high. Long procedural duration and the use of adjunctive techniques are associated with increased risk of reinterventions.

Anatomical analysis of the aortic arch and feasibility study of double and triple branched thoracic endografts in the treatment of isolated arch pathologies.

OBJECTIVES: The aim of this study was to determine the proportion of patients undergoing open arch repair who would be anatomically suitable for multi-branched endovascular arch repair. METHODS: This study was a single-centre review of patients undergoing open arch repair between 2000 and 2020. Anatomical feasibility was determined by comparing arch measurements to the anatomical criteria of the Zenith® double and triple inner branched-arch endografts (Cook Medical) and the Relay® double arch branched device (Terumo-Aortic). RESULTS: Ninety (90) patients were included in this study, with 43/90 presenting degenerative aneurysm. The distance between the sinotubular junction and the brachiocephalic trunk measured 114 ± 30 mm on the outer curvature, and the maximum diameter of the proximal landing zone (PLZ) was 41 ± 11mm. A total of 42/90 patients (47%) were anatomically suitable for at least 1 stent graft and 29/90 patients (32%) were eligible for a triple-branched endograft. The most important determinant factors of anatomical suitability were the PLZ diameter (Cramer's V = 0.743, P < 0.001) and length (Cramer's V = 0.777, P < 0.001). CONCLUSIONS: This study shows that the proportion of patients who may be anatomically suitable for branched-arch repair remains limited. The PLZ dimensions tend to be the most important anatomical limitations and should receive more emphasis in the development of branched-arch devices.

A systematic review of management of superficial venous reflux in the setting of deep venous obstruction.

BACKGROUND: Because of the fear of obliterating the collateral outflow path and thus worsening venous hypertension, many physicians believe that deep venous obstruction (DVO) is a contraindication for the treatment of superficial venous reflux (SVR). In the present review, we have described the available clinical data for this important group of patients. METHODS: A literature search was performed of PubMed, Web of Science, and Google Scholar to identify clinical research studies reported between 1991 and 2021 that had evaluated the concomitant management of SVR and DVO. Studies were excluded if they had included fewer than five patients, had not specified the interventions used to treat SVR, or had no follow-up data available. All the studies included were observational, and their quality was assessed using the Newcastle-Ottawa scale. RESULTS: Ten retrospective cohort studies were included, with a total of 2476 limbs in 2428 patients, with concurrent SVR and DVO or a known history of deep vein thrombosis treated in 944 limbs. Of the 10 studies, 8 were comparative. The level of DVO was suprainguinal, when specified, in most cases. The mean age range was 42 to 65 years, 1432 patients (59%) were women, and advanced chronic venous disease (ie, CEAP [clinical, etiologic, anatomic, pathophysiologic] class 4-6) was present in 614 limbs (70%), with two studies reporting uniquely on C6 patients. Of the 944 limbs treated for concomitant SVR and DVO, a combination of saphenous vein ablative procedures and deep venous stenting was performed in 483 limbs (51.2%), saphenous vein ablative procedures alone in 293 limbs (31%), and deep venous stenting alone in 168 (17.8%). Of the five studies comparing the different treatment strategies to treat concurrent SVR and DVO, four reported better outcomes after a combination of deep venous stenting and saphenous vein ablation compared with ablation alone. Studies comparing the outcomes of saphenous ablation for patients with reflux alone vs patients with concurrent reflux and DVO did not find any significant differences in clinical improvement and postoperative complication rates. CONCLUSIONS: The current evidence is weak owing to the limited number of studies and small sample size but suggests that ablation of SVR is safe for patients with concurrent DVO. Patients with advanced venous disease and iliac vein obstruction had better results when SVR ablation was combined with treatment of iliac vein obstruction. Additional contemporary studies are needed to confirm the safety and specifically investigate the efficacy of SVR ablation in relieving the symptoms of patients with concurrent infrainguinal obstruction.

The "Skewer Technique" for Stentgraft Delivery in the Aortic Arch: Advancing the Dilatator in The Innominate Artery Over a Right Femoro-Brachial Through-And-Through Wire.

BACKGROUND: Thoracic endovascular aortic repair (TEVAR) is the preferred treatment for different aortic pathologies, because it has reduced mortality and morbidity rates. However, TEVAR is not feasible in all cases due to aortic angulations, the hemodynamics of the aortic arch and narrow or tortuous iliofemoral access. Therefore, different adjuvant techniques, such as iliac percutaneous transluminal angioplasty, iliathrough-and-through guidewires and external transapical guidewires have been previously reported. Herein we describe the Skewer Technique for successful TEVAR delivery, through a right-brachial-femoral through-and-through guidewire and advancement of the delivery system into the innominate artery. METHODS: A 38-year-old male presented with a symptomatic 11.5cm thoracic aneurysm with involvement of the left-subclavian artery ostium. The patient underwent left carotid-subclavian bypass and a TEVAR. Due to the huge size of the aneurysm a left-brachial-right femoral artery through-and-through guidewire was established. However, the achievement of a stable position for the deployment of the stentgraft was not possible. Eventually, the exclusion of the aneurysm was done with a right brachio-femoral through-and-through wire, inserting the proximal part of the delivery system into the innominate artery. CONCLUSIONS: The use of adjuvant techniques such as a through-and-through right brachial-femoral guidewire with advancement of the endograft delivery system in the innominate artery (Skewer Technique) represents a useful alternative option in cases where the angulations of the aortic arch impede the deployment of the stent graft using conventional techniques.