Solid state, pulsed-wave 355 nm UV laser atherectomy debulking in the treatment of infrainguinal peripheral arterial disease: The Pathfinder Registry.

BACKGROUND: Atherectomy is an important option for debulking atherosclerotic plaque from diseased arteries in patients with infrainguinal arterial disease. Laser atherectomy uses a high-powered laser to remove the plaque from the arteries to restore blood flow. AIMS: The Pathfinder multicenter registry was initiated to evaluate the safety and efficacy of the 355 nm laser atherectomy system in a real-world setting for the treatment of de novo, re-stenotic and in-stent restenosis (ISR) lesions in infrainguinal arteries of patients with peripheral artery disease (PAD). METHODS: The study was a prospective, single-arm, multicenter, open-label registry study for patients treated with the 355 nm laser system. Clinical and lesion characteristics, procedural safety and efficacy data, and baseline, 6-, and 12-month outcomes data, including Ankle Brachial Index (ABI), Rutherford class, and Walking Impairment Questionnaires (WIQ), were collected. The primary efficacy endpoint was the achievement of ≤30% final residual stenosis at the index lesion postatherectomy and adjunctive therapy evaluated by an angiographic Core Lab. The primary safety endpoint was the percentage of subjects who did not experience periprocedural major adverse events (PPMAEs) before discharge. RESULTS: One hundred and two subjects with 121 lesions treated with the 355 nm laser device at 10 centers were included in the analysis. Mean age was 68.4 ± 10.21 years, 61.8% of subjects were male, 44.6% had critical limb ischemia (CLI), and 47.3% had tibial lesions. The mean residual stenosis at the end of the procedure was 24.4 ± 15.5 with 69 lesions (69.0%) achieving technical procedural success (<30% stenosis); similar rates were observed for subjects with ISR (25.5 ± 14.9), chronic total occlusion (CTO) (28.1 ± 17.0), and severe calcification (36.5 ± 21.6) lesions. Mean ABI, Rutherford, and WIQ scores were improved at both 6 and 12 months. Ninety-seven of 102 subjects (95.1%) met the primary safety endpoint of not experiencing a PPMAE before discharge. CONCLUSIONS: The initial data from the Pathfinder Registry demonstrates the 355 nm laser system is safe and effective in a real-world setting for performing atherectomy in patients with infrainguinal PAD.

PACE: randomized, controlled, multicentre, multinational, phase III study of PLX-PAD for critical limb ischaemia in patients unsuitable for revascularization: randomized clinical trial.

BACKGROUND: Revascularization is the primary treatment modality for chronic limb-threatening ischaemia (CLTI), but is not feasible in all patients. PLX-PAD is an off-the-shelf, placental-derived, mesenchymal stromal cell-like cell therapy. This study aimed to evaluate whether PLX-PAD would increase amputation-free survival in people with CLTI who were not candidates for revascularization. METHODS: People with CLTI and minor tissue loss (Rutherford 5) who were unsuitable for revascularization were entered into a randomized, parallel-group, placebo-controlled, multinational, blinded, trial, in which PLX-PAD was compared with placebo (2 : 1 randomization), with 30 intramuscular injections (0.5 ml each) into the index leg on days 0 and 60. Planned follow-up was 12-36 months, and included vital status, amputations, lesion size, pain and quality-of-life assessments, haemodynamic parameters, and adverse events. RESULTS: Of 213 patients enrolled, 143 were randomized to PLX-PAD and 70 to placebo. Demographics and baseline characteristics were balanced. Most patients were Caucasian (96.2%), male (76.1%), and ambulatory (85.9%). Most patients (76.6%) reported at least one adverse event, which were mostly expected events in CLTI, such as skin ulcer or gangrene. The probability of major amputation or death was similar for placebo and PLX-PAD (33 and 28.6% respectively; HR 0.93, 95% c.i. 0.53 to 1.63; P = 0.788). Revascularization and complete wound healing rates were similar in the two groups. A post hoc analysis of a subpopulation of 121 patients with a baseline haemoglobin A1c level below 6.5% showed improved 12-month amputation-free survival (HR 0.46, 0.21 to 0.99; P = 0.048). CONCLUSION: Although there was no evidence that PLX-PAD reduced amputation-free survival in the entire study population, benefit was observed in patients without diabetes mellitus or whose diabetes was well controlled; this requires confirmation in further studies. Trial registration: NCT03006770 (http://www.clinicaltrials.gov); 2015-005532-18 (EudraCT Clinical Trials register - Search for 2015-005532-18).

Drug-Eluting Resorbable Scaffold versus Angioplasty for Infrapopliteal Artery Disease.

BACKGROUND: Among patients with chronic limb-threatening ischemia (CLTI) and infrapopliteal artery disease, angioplasty has been associated with frequent reintervention and adverse limb outcomes from restenosis. The effect of the use of drug-eluting resorbable scaffolds on these outcomes remains unknown. METHODS: In this multicenter, randomized, controlled trial, 261 patients with CLTI and infrapopliteal artery disease were randomly assigned in a 2:1 ratio to receive treatment with an everolimus-eluting resorbable scaffold or angioplasty. The primary efficacy end point was freedom from the following events at 1 year: amputation above the ankle of the target limb, occlusion of the target vessel, clinically driven revascularization of the target lesion, and binary restenosis of the target lesion. The primary safety end point was freedom from major adverse limb events at 6 months and from perioperative death. RESULTS: The primary efficacy end point was observed (i.e., no events occurred) in 135 of 173 patients in the scaffold group and 48 of 88 patients in the angioplasty group (Kaplan-Meier estimate, 74% vs. 44%; absolute difference, 30 percentage points; 95% confidence interval [CI], 15 to 46; one-sided P<0.001 for superiority). The primary safety end point was observed in 165 of 170 patients in the scaffold group and 90 of 90 patients in the angioplasty group (absolute difference, -3 percentage points; 95% CI, -6 to 0; one-sided P<0.001 for noninferiority). Serious adverse events related to the index procedure occurred in 2% of the patients in the scaffold group and 3% of those in the angioplasty group. CONCLUSIONS: Among patients with CLTI due to infrapopliteal artery disease, the use of an everolimus-eluting resorbable scaffold was superior to angioplasty with respect to the primary efficacy end point. (Funded by Abbott; LIFE-BTK ClinicalTrials.gov number, NCT04227899.).

Percutaneous Deep Venous Arterialization in Patients with No-Option Critical Limb Ischemia Performed in an Office-Based Laboratory Setting.

PURPOSE: To evaluate the feasibility and safety of percutaneous deep venous arterialization (pDVA) performed in an office-based laboratory (OBL) for patients with no-option critical limb ischemia (CLI). MATERIALS AND METHODS: A retrospective chart review was performed of all patients who underwent pDVA using commercially available devices from January 2018 to November 2021 in a single OBL. In total, 22 patients (10 males and 12 females; Rutherford 4, 5, and 6: n = 1, 8, and 13, respectively) were identified with a median follow-up of 140 days. Amputation-free survival, wound healing, pDVA patency, and overall survival were evaluated at 30 days, 6 months, and throughout the remaining follow-up period. RESULTS: All patients had undergone failed previous attempts at endovascular arterial reconstruction. At 6 months after procedure, 6.4% of arteriovenous conduits remained patent; 83.3% (10/12) of patients experienced complete or partial wound healing. In addition, 78.6% of patients avoided an above-ankle amputation, and overall survival was 83.6%. Nine patients underwent endovascular reinterventions at 6 months. One mild adverse event and 4 moderate adverse events occurred after procedure, and 1 cardiac death occurred 5 days after procedure. CONCLUSIONS: pDVA is safe and feasible in the OBL for patients with no-option CLI. Many patients avoided an above-ankle amputation during the study period despite low overall pDVA patency.

Randomized controlled trial of mechanical thrombectomy vs catheter-directed thrombolysis for acute hemodynamically stable pulmonary embolism: Rationale and design of the PEERLESS study.

BACKGROUND: The identification of hemodynamically stable pulmonary embolism (PE) patients who may benefit from advanced treatment beyond anticoagulation is unclear. However, when intervention is deemed necessary by the PE patient's care team, data to select the most advantageous interventional treatment option are lacking. Limiting factors include major bleeding risks with systemic and locally delivered thrombolytics and the overall lack of randomized controlled trial (RCT) data for interventional treatment strategies. Considering the expansion of the pulmonary embolism response team (PERT) model, corresponding rise in interventional treatment, and number of thrombolytic and nonthrombolytic catheter-directed devices coming to market, robust evidence is needed to identify the safest and most effective interventional option for patients. METHODS: The PEERLESS study (ClinicalTrials.gov identifier: NCT05111613) is a currently enrolling multinational RCT comparing large-bore mechanical thrombectomy (MT) with the FlowTriever System (Inari Medical, Irvine, CA) vs catheter-directed thrombolysis (CDT). A total of 550 hemodynamically stable PE patients with right ventricular (RV) dysfunction and additional clinical risk factors will undergo 1:1 randomization. Up to 150 additional patients with absolute thrombolytic contraindications may be enrolled into a nonrandomized MT cohort for separate analysis. The primary end point will be assessed at hospital discharge or 7 days post procedure, whichever is sooner, and is a composite of the following clinical outcomes constructed as a hierarchal win ratio: (1) all-cause mortality, (2) intracranial hemorrhage, (3) major bleeding, (4) clinical deterioration and/or escalation to bailout, and (5) intensive care unit admission and length of stay. The first 4 components of the win ratio will be adjudicated by a Clinical Events Committee, and all components will be assessed individually as secondary end points. Other key secondary end points include all-cause mortality and readmission within 30 days of procedure and device- and drug-related serious adverse events through the 30-day visit. IMPLICATIONS: PEERLESS is the first RCT to compare 2 different interventional treatment strategies for hemodynamically stable PE and results will inform strategy selection after the physician or PERT determines advanced therapy is warranted.

Treatment effect of medial arterial calcification in below-knee after Auryon laser atherectomy using micro-CT and histologic evaluation.

PURPOSE: To determine the frequency of medial arterial calcification (MAC) fracture following Auryon laser atherectomy using micro-CT and histologic evaluation in an atherosclerotic human cadaveric limb model. METHODS: Two below-the-knee calcified arterial segments from human cadaver limbs underwent treatment with the Auryon laser system with or without plain old balloon angioplasty (POBA). Micro-CT and angiography were performed before and after treatment followed by histological evaluation of regions showing calcium disruption. RESULTS: All treatment zones were successfully treated with the Auryon laser (n = 9). Six of 9 treatment zones showed calcium fracture on micro-CT. Each treatment zone was further subdivided using micro-CT analysis (36 evaluated sections) of which 18 sections revealed calcium fracture. Sections with calcium fracture had significantly more confluent and uninterrupted circumferential calcification than sections without calcium fracture (arc of calcification 360.0 [323.7-360.0] vs 312.8 [247.4-314.2] degree, p = 0.007), whereas there were no differences in size of calcium burden (3.4 [2.8-3.9] vs 2.8 [1.3-4.6] mm2, p = 0.46). No arterial dissection or rupture was seen. CONCLUSIONS: Auryon laser atherectomy produced fractures of medial arterial calcification in this cadaveric human atherosclerotic peripheral artery model. This effect was observed in arterial segments with a pattern of circumferential uninterrupted calcification (i.e. larger arc of calcification) regardless of calcium burden. Our pilot data suggests Auryon laser may be a promising therapy for calcified lesions.

Deep Venous Arterialization: Background, Patient Selection, Technique, Outcomes and Follow-up, and Future Implementation.

Critical limb-threatening ischemia (CLTI) is a severe manifestation of peripheral arterial disease with a highly increased risk for morbidity and mortality that has limited and suboptimal opportunities for treatment, ultimately resulting in major amputation for patients. Deep venous arterialization (DVA) provides a suitable limb salvage option for "no-option" patients facing amputation by introducing an artificial anastomosis between a site of proximal arterial inflow and retrograde venous outflow to deliver tissue perfusion to lower extremity wounds. Because DVAs are employed as a last-resort effort in CLTI patients, it is important to provide updated information on indications for usage, strategies in creating DVA conduits, and discussion of outcomes and expectations for patients undergoing this procedure. Additionally, variations in method, including use of various techniques and devices, are explored. The authors provide an up-to-date review of the literature and discuss pertinent procedural and technical considerations for utilizing DVAs in CLTI patients.

Balloon Angioplasty of Infrapopliteal Arteries: A Systematic Review and Proposed Algorithm for Optimal Endovascular Therapy.

Endovascular revascularization has been increasingly utilized to treat patients with chronic limb-threatening ischemia (CLTI), particularly atherosclerotic disease in the infrapopliteal arteries. Lesions of the infrapopliteal arteries are the result of 2 different etiologies: medial calcification and intimal atheromatous plaque. Although several devices are available for endovascular treatment of infrapopliteal lesions, balloon angioplasty still comprises the mainstay of therapy due to a lack of purpose-built devices. The mechanism of balloon angioplasty consists of adventitial stretching, medial necrosis, and dissection or plaque fracture. In many cases, the diffuse nature of infrapopliteal disease and plaque complexity may lead to dissection, recoil, and early restenosis. Optimal balloon angioplasty requires careful attention to assessment of vessel calcification, appropriate vessel sizing, and the use of long balloons with prolonged inflation times, as outlined in a treatment algorithm based on this systematic review. Further development of specific devices for this arterial segment are warranted, including devices for preventing recoil (eg, dedicated atherectomy devices), treating dissections (eg, tacks, stents), and preventing neointimal hyperplasia (eg, novel drug delivery techniques and drug-eluting stents). Further understanding of infrapopliteal disease, along with the development of new technologies, will help optimize the durability of endovascular interventions and ultimately improve the limb-related outcomes of patients with CLTI.

Stromal Cell-Derived Factor-1 Plasmid Treatment for Patients With Peripheral Artery Disease (STOP-PAD) Trial: Six-Month Results.

Purpose: To present the 6-month results of the Stromal Cell-Derived Factor-1 Plasmid Treatment for Patients with Peripheral Artery Disease (STOP-PAD) trial. The trial was an attempt to alter the course of chronic limb-threatening ischemia (CLTI) with a biological agent vs placebo after successful arterial revascularization at or below the knee. Materials and Methods: The multicenter, randomized, double-blinded, placebo-controlled, phase 2B STOP-PAD trial (ClinicalTrials.gov identifier NCT02544204) randomized 109 patients (mean age 71 years; 68 men) with Rutherford category 5 or 6 CLTI and evidence of persistent impaired forefoot perfusion following recent successful revascularization to 8- (n=34) or 16-mg (n=36) intramuscular injections of a non-viral DNA plasmid-based treatment vs placebo (n=34). The primary efficacy outcome was the 6-month wound healing score evaluated by an independent wound core laboratory; the primary safety endpoint was major adverse limb events (MALE), a composite of major amputation plus clinically-driven target lesion revascularization at 6 months. Results: Only one-third of the patients had complete wound healing at 6 months in the placebo (31%), 8-mg injection (33%), and 16-mg injection (33%) groups. In addition, the observed increase in the toe-brachial index from baseline to 6 months was statistically significant in each group; however, this did not result in lower rates of MALE at 6 months (24% in the placebo, 29% in the 8-mg injection, and 11% in the 16-mg injection groups). During the 6-month period, 6 patients (6%) died, and 24 patients (23%) had an amputation [only 4 (4%) major]. Conclusion: Combining revascularization and biological therapy failed to improve outcomes in CLTI at 6 months. STOP-PAD has provided insights for future trials to evaluate biological therapy.

Acute and 30-Day Safety and Effectiveness Evaluation of Eximo Medical's B-Laser™, a Novel Atherectomy Device, in Subjects Affected With Infrainguinal Peripheral Arterial Disease: Results of the EX-PAD-03 Trial.

BACKGROUND: B-Laser™ is a novel atherectomy device that uses a solid-state third harmonic pulsed Nd:YAG laser with an output of 355 nm. Early data showed that the B-Laser™ is safe in treating a broad range of infrainguinal arterial lesions. We present the results of the EX-PAD-03 U.S. pivotal trial of the EXIMO B-Laser™. METHODS: EX-PAD-03 is a prospective, single-arm, multi-center, international, open-label, clinical study. The study enrolled patients in the United States and Europe. The primary efficacy endpoint was the average reduction in residual diameter stenosis of >20% from baseline prior to any adjunctive therapy achieved by the B-Laser™ catheter alone. The primary safety endpoint was freedom from major adverse events (MAEs) defined as: unplanned target limb amputation above the ankle, clinically driven target lesion revascularization (CD-TLR) and cardiovascular related death. RESULTS: A total of 97 subjects (107 lesions) were enrolled. Mean age was 70.5 years and 51% were males. Diabetes mellitus was present in 42.3%. Mean lesion length was 53.96 ±â€¯43.18 mm and 26.2% had severe calcification. Lesions were de novo (79.4%), followed by in-stent restenosis (ISR) (15.9%) and non in-stent restenosis (4.7%). The mean percent stenosis at the target lesion as assessed by the Core lab was 85.7% ±â€¯12.2 (femoro-popliteal 85.6 ±â€¯12.8%; tibials 86.0 ±â€¯9.6%). Post B-Laser™ and prior to adjunctive therapy, the mean percent stenosis at the target lesion was 52.1%. This resulted in a mean reduction from baseline to post B-Laser™ of 33.6% ±â€¯14.2% meeting the primary efficacy endpoint goal. The freedom from MAE through the 30-day follow-up period after intervention was 98.9%. Per Core lab, there was no device-related distal embolization, dissections that required additional therapy, perforation, or pseudoaneurysm. Bailout stenting was 0.9%. A significant improvement from baseline in ABI (0.24 ±â€¯0.18), Rutherford category (-1.79 ±â€¯1.22) and WIQ (0.26 ±â€¯0.28) were noted at 1 month. There was no target lesion revascularization and the patency was 96.8% by duplex ultrasound criteria at 30-day follow up. CONCLUSION: The Eximo B-Laser™ is effective and safe in ablating atherosclerotic and restenotic tissue for both above and below the knee obstructive arterial disease. The device has a high safety profile including a low risk of distal embolization.

Novel laser-based catheter for peripheral atherectomy: 6-month results from the Eximo Medical B-Laser™ IDE study.

BACKGROUND: The B-Laser™ atherectomy system (Eximo Medical, Israel) is a 355 nm solid-state Nd:YAG short pulse laser for de-novo and restenotic infrainguinal PAD with enhanced affinity for atheroma and calcified plaque. METHODS: The study was a prospective, single-arm, multi-center, international, open-label study assessing the B-Laser™ in symptomatic (Rutherford 2 to 4) infrainguinal peripheral artery disease. Primary core lab efficacy was mean reduction in diameter stenosis >20% by the B-Laser™ catheter alone. Cardiovascular death, major amputation, target lesion revascularization, WIQ, ABI and Rutherford class were obtained at baseline and out to 6 months. Duplex ultrasound patency (PSVR <2.5), was evaluated by Core Lab. RESULTS: 97 (77 in USA) PAD subjects (51 male, mean 70.5 years [range 46-86]) with 107 lesions were treated with B-Laser™ (average length 5.4 cm [range 1-24], 29.0% infrapopliteal. 77.6% calcification [26.2% severe], 21.5% chronic total occlusions, 20.6% re-stenotic). Average reduction in residual stenosis post B-Laser™ alone was 33.6 ± 14.2%. Baseline and final stenosis (post laser and adjunctive therapy) were 85.7 ± 12.2% and 17.7 ± 11.0%, respectively. Duplex patency was 96.8% at 30-days and 85.6% at 6 months (95.7% 6-month patency with severe calcification), and did not differ between POBA vs. DCB sub-groups. ABI, Rutherford category and WIQ all improved. There was one MAE and three TLRs out of 101 lesions. No procedural distal embolization was noted and there were no major device-related dissections. CONCLUSIONS: Experience with the B-Laser™ atherectomy system in infrainguinal PAD procedures demonstrates a high level of safety and efficacy for denovo and restenotic infrainguinal arterial lesions.

Dissections After Infrainguinal Percutaneous Transluminal Angioplasty: A Systematic Review and Current State of Clinical Evidence.

Purpose: To systematically review the literature and extract information on the definitions, prevalence, implications, and treatment of dissections after infrainguinal balloon angioplasty, with a goal of summarizing current data and identifying gaps in knowledge to help direct future research. Materials and Methods: A systematic review was performed according to the PRISMA guidelines. Medline (PubMed), Scopus, and Cochrane CENTRAL databases were reviewed for prospective and retrospective studies reporting dissection identification, characterization, incidence, severity, and/or outcomes after infrainguinal balloon angioplasty up to January 30, 2019. The electronic search resulted in 288 studies. From these, 153 full-text articles were assessed, and 51 published from 1964 to 2018 were selected as relevant to this systematic review. Because of the significant between-study differences in lesion characteristics, reporting methods, and lack of core laboratory adjudication, the findings were summarized from each study, but the results were not pooled. Results: The mechanism of percutaneous transluminal angioplasty (PTA) consists of adventitial stretching, medial necrosis, and controlled dissection or plaque fracture. PTA-induced dissections can precipitate pathological high and low shear hemodynamic defects and have been implicated as a contributing factor in procedural complications as well as restenosis at the treatment site. The development of significant dissection after PTA often leads to the use of adjunctive therapies, including stent placement. Despite the ubiquitous nature of dissection after balloon angioplasty (incidence 7.4% to 84%), limited data are available to categorize dissections in the peripheral arteries and direct subsequent treatments to improve vessel patency. With the increased utilization of drug-coated balloon angioplasty, understanding the outcomes of postangioplasty dissection has become increasingly important, as the decision to treat dissections with additional strategies has therapeutic and economic implications. Conclusion: All post-PTA dissections in the femoropopliteal arteries may benefit from a treatment approach that ensures optimal hemodynamics with long-term durability in treated lesions. Further understanding the importance of postangioplasty dissections, along with the development of new technologies, will help optimize the patency of endovascular interventions.

A Percutaneous Crossing Algorithm for Femoropopliteal and Tibial Artery Chronic Total Occlusions (PCTO Algorithm).

Peripheral artery chronic total occlusions (PCTOs) are frequently encountered during endovascular treatment of peripheral artery disease. Failure to successfully cross PCTOs accounts for the majority of unsuccessful endovascular procedures and associated complications. This review outlines a contemporary ultrasound-based approach to crossing femoropopliteal (FP) PCTOs based on a review of prospectively collected case report surveys, published evidence, and expert opinion compiled by the writing group members. The authors describe optimal imaging of PCTO lesions as well as key angiographic and ultrasound imaging features for determining the choice of antegrade, retrograde, or hybrid techniques, initial guidewire selection, guidewire escalation, and dissection re-entry approaches. These concepts are illustrated using clearly defined hierarchical steps and case examples. The writing group members recognize that while the algorithm provided may not encompass all clinical situations, it will serve as a foundation for establishing a systematic procedural strategy for crossing PCTOs to maximize crossing efficiency, treatment success, and patient safety.

SDF-1 plasmid treatment for patients with peripheral artery disease (STOP-PAD): Randomized, double-blind, placebo-controlled clinical trial.

The efficacy of biologic therapies in critical limb ischemia (CLI) remains elusive, in part, due to limitations in trial design and patient selection. Using a novel design, we examined the impact of complementing revascularization therapy with intramuscular JVS-100 - a non-viral gene therapy that activates endogenous regenerative repair pathways. In this double-blind, placebo-controlled, Phase 2B trial, we randomized 109 patients with CLI (Rutherford class V or VI) to 8 mg or 16 mg intramuscular injections of placebo versus JVS-100. Patients were eligible if they persistently had reduced forefoot perfusion, by toe-brachial index (TBI) or skin perfusion pressure (SPP), following successful revascularization with angiographic demonstration of tibial arterial flow to the ankle. The primary efficacy end point was a 3-month wound healing score assessed by an independent wound core laboratory. The primary safety end point was major adverse limb events (MALE). Patients' mean age was 71 years, 33% were women, 79% had diabetes, and 8% had end-stage renal disease. TBI after revascularization was 0.26, 0.27, and 0.26 among the three groups (placebo, 8 mg, and 16 mg injections, respectively). Only 26% of wounds completely healed at 3 months, without any differences between the three groups (26.5%, 26.5%, and 25%, respectively). Similarly, there were no significant changes in TBI at 3 months. Three (2.8%) patients died and two (1.8%) had major amputations. Rates of MALE at 3 months were 8.8%, 20%, and 8.3%, respectively. While safe, JVS-100 failed to improve wound healing or hemodynamic measures at 3 months. Only one-quarter of CLI wounds healed at 3 months despite successful revascularization, highlighting the need for additional research in therapies that can improve microcirculation in these patients. ClinicalTrials.gov Identifier: NCT02544204.

Visceral Artery Aneurysms: Diagnosis, Surveillance, and Treatment.

Visceral artery aneurysms (VAAs) are a rare, but serious clinical entity as rupture confers a high rate of mortality. Data regarding the prevalence, treatment, and prognosis of VAAs is largely from case series, as true randomized trials are lacking. The incidence of VAAs has risen over the decades with advances in imaging technology, availability, and utilization. Even in the presence of symptoms, the prompt diagnosis of VAAs may be challenging as symptoms are often nonspecific and varied. Although there are no definitive treatment guidelines, asymptomatic VAAs require treatment in the following scenarios: when the aneurysm diameter is greater than 2 cm, when identified during pregnancy, when multiple aneurysms are present, and in the case of hepatic transplant. Similar to therapeutic trends in other vascular beds, advances in endovascular devices and techniques have driven an "endovascular first" approach for the treatment of VAAs. However, although the success rates of endovascular repair are impressive, surgical intervention is still necessary in treating centers. This paper reviews the pathophysiology, clinical features, anatomic characteristics, and management strategies required for the effective diagnosis and treatment of VAAs.

Design Strategies for Global Clinical Trials of Endovascular Devices for Critical Limb Ischemia (CLI)　- A Joint USA-Japanese Perspective.

For more than 10 years, the Harmonization by Doing (HBD) program, a joint effort by members from academia, industry and regulators from the United States of America (USA) and Japan, has been working to increase timely regulatory approval for cardiovascular devices through the development of practical global clinical trial paradigms. Consistent with this mission and in recognition of the increasing global public health effects of critical limb ischemia (CLI), academic and government experts from the USA and Japan have developed a basic framework of global clinical trials for endovascular devices for CLI. Despite differences in medical and regulatory environments and complex patient populations in both countries, we developed a pathway for the effective design and conduct of global CLI device studies by utilizing common study design elements such as patients' characteristics and study endpoints, and minimizing the effect of important clinical differences. Some of the key recommendations for conducting global CLI device studies are: including patients on dialysis; using a composite primary endpoint for effectiveness that includes 6-month post-procedure therapeutic success and target vessel patency; and using a 30-day primary safety endpoint of perioperative death and major adverse limb events. The proposed approach will be uniquely beneficial in facilitating both the initiation and interpretation of CLI studies and accelerating worldwide CLI device development and innovation.