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

Prospective, Multi-center, Single-Arm Study of the Auryon Laser System for Treatment of Below-the-Knee Arteries in Patients With Chronic Limb-Threatening Ischemia: 30-Day Results of the Auryon BTK

The 355 nm Auryon laser (AngioDynamics, Inc., Latham, New York) has been shown to be effective and safe in treating various morphology lesions in the femoropopliteal arteries. There are limited data on the Auryon laser in treating below-the-knee (BTK) arteries in patients with chronic limb-threatening ischemia. We present the 30-day efficacy and safety findings from the ongoing Auryon BTK study. Patients with chronic limb-threatening ischemia were prospectively enrolled in the Auryon BTK study between March 2022 and February 2023 in 4 US centers after obtaining written informed consent. The primary safety end point included major adverse limb events + postoperative death at 30 days, defined as a composite of all-cause death, major amputation, and target vessel revascularization. Demographic, procedural, angiographic, and outcome data were collected. A total of 60 patients (61 lesions) were treated. The mean age was 74.6 ± 10.3 years, with 65.0% men, 58.3% with diabetes, 43.3% Rutherford Becker (RB) IV, and 56.7% RB V. Of the 61 lesions, 59% had severe calcification, 31.1% were chronic total occlusions, and 90.2% were de novo disease. The baseline diameter stenosis was 80.2 ± 16.4%, after laser 57.4 ± 21.7%, and after final treatment 24.0 ± 23.1% (p <0.0050). The primary performance end point showed a procedure success rate of 37 of 68 (63.8%). Bailout stenting occurred in 1 of 61 lesions (1.6%). The RB category was 100% RB IV or higher at baseline versus 35.3% at 30 days. At 30 days, there was no target vessel revascularization and the patency was 88.9% (Peak Systolic Velocity Ratio (PSVR) ≤2.4). In conclusion, the Auryon laser is safe and relatively effective in treating BTK lesions with minimal complications.

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.

Trends in outcomes associated with the use of Auryon atherectomy system in a real-world setting

BACKGROUND

While endovascular approaches are considered first line treatment for stenosis or occlusion of the lower limb arteries, major dissections and embolic events remain procedural risks. Newer technologies are needed which limit these complications while achieving desired clinical outcomes.

METHODS

The Auryon atherectomy system (AngioDynamics) consists of a 355-nm wavelength solid-state Nd:YAG short pulse laser combined with dedicated optical catheters. This single-center, retrospective chart review assessed the safety and efficacy of this device in patients with PAD treated at our center between March and December 2020.

RESULTS

A total of 55 patients were included. Mean age was 73.7 ± 9.3 years with 63.6 % of patients being males. Lesions were above the knee only for 16.4 % of patients, below the knee only for 3.6 %, and both above and below the knee for 80.0 % of patients. One patient had in-stent restenosis. Chronic total occlusions and critical limb ischemia were present for 43.6 % of patients respectively. Procedural success, defined as <30 % residual stenosis without any complications, was achieved in 85.5 % of patients. Stenosis/re-occlusion occurred in 25.5 % of patients at a mean of 168.9 ± 73.4 days with resultant target lesion revascularization (TLR) at 218.3 ± 92.4 days. Four patients underwent minor amputations. No patients experienced procedure-related complications. One patient died unrelated to the procedure.

CONCLUSION

The Auryon laser system was shown to be safe and effective in this real-world patient population with no procedural adverse events or deaths and improvements in patient outcomes.

Ablation of porcine subcutaneous fat and porcine aorta tissues by a burst-mode nanosecond-pulsed laser at 355 nm

High-energy laser pulses used in laser angioplasty are challenging the laser cost, delivery system damage, efficiency, and laser catheter operating time. 355 nm nanosecond-pulsed laser in burst mode has shown potentials in reducing the system complexity and selective ablation of tissues. In this paper, burst mode laser ablation of porcine subcutaneous fat and porcine aorta is investigated. A histopathological analysis demonstrates that porcine subcutaneous fat can be ablated at a rate of greater than 0.2 mm/s when the number of pulses per burst is 1500 (corresponding to a fluence of 0.12 mJ/mm² per pulse and 180 mJ/mm² per burst), and the temperature of tissue during lasing is lower than 45°C. The porcine aorta remains nearly unaffected at the same laser parameter, and the tissue temperature during lasing is lower than 35°C. It shows the feasibility of using a burst-mode laser for selective ablation of tissue.

State-of-the-Art Endovascular Therapies for the Femoropopliteal Segment: Are We There Yet?

Peripheral arterial disease is an increasingly prevalent condition with significant associated morbidity, mortality, and health care expenditure. Endovascular interventions are appropriate for most patients with either ongoing symptoms of intermittent claudication despite lifestyle and medical optimization or chronic limb-threatening ischemia. The femoropopliteal segment is the most common arterial culprit responsible for claudication and the most commonly revascularized segment. Endovascular approaches to revascularization of the femoropopliteal segment are advancing with an evolving landscape of techniques for arterial access, device-based therapies, vessel preparation, and intraprocedural imaging. These advances have been marked by debate and controversy, notably related to the safety of paclitaxel-based devices and necessity of atherectomy. In this review, we provide a critical overview of the current evidence, practice patterns, emerging evidence, and technological advances for endovascular intervention of the femoropopliteal arterial segment.

Atherectomy vs Other Modalities for Treatment During Peripheral Vascular Intervention

PURPOSE OF THE REVIEW

Calcified atheroma is frequently encountered in peripheral vascular intervention. Standard treatment with balloon and/or stenting alone does poorly in these cases due to vessel recoil, suboptimal luminal gain, and inadequate stent expansion. In light of the above challenges with angioplasty and stenting for PAD, endovascular atherectomy has emerged as a novel technology for atheroma treatment and removal, offering the benefits of surgical endarterectomy in a minimally invasive percutaneous approach. This review outlines the endovascular atherectomy devices available in clinical practice to date, compares and contrasts their mode of action, summarizes the relevant published data on indication and role of atherectomy over other treatment modalities for PAD, and discusses the future prospective on this emerging technology.

RECENT FINDINGS

Currently, there are host of peripheral atherectomy devices available with unique mechanism of action and relative advantages and disadvantages. Despite these recent technological advancements, there remains a paucity of data from well-designed studies regarding the superiority of atherectomy as an adjunctive treatment versus standard treatment with balloon and stenting. Emerging data have supported its use to improve patency rates in conjunction with drug-coated balloons. Although associated risks, including distal embolization and perforation, are often marginal, the cost of these devices to the healthcare system necessitates further investment in to establishing level 1 data to support their use. Peripheral atherectomy has the potential to improve limb-related outcomes, potentially through reduced need for bail-out scaffolds and improved drug uptake. Nonetheless, further investment in the evidence foundation supporting these devices versus standard practices is required.

How Much Debulking with Atherectomy is Enough When Treating Infrainguinal Arterial Interventions? The Balance Between Residual Stenosis and Adventitial Injury

Atherectomy is an effective vessel prepping device but not all atherectomy devices are equal. The depth of vessel injury and residual narrowing vary considerably among atherectomy devices with significant implications on outcome. Precision imaging is critical to optimize outcome using atherectomy as a vessel prepping technique. Prospective trials need to test the hypothesis that precision imaging has a significant impact on how operators approach the treatment of infrainguinal arterial disease.

National trends and variability of atherectomy use for peripheral vascular interventions from 2010 to 2019

OBJECTIVES

Small, older studies suggest atherectomy devices have become common in peripheral vascular interventions (PVI) despite the paucity of strong clinical guidelines. We analyzed the 10-year trends in the use of atherectomy for PVI across the United States and identified main predictors of atherectomy use.

METHODS

Using the Vascular Quality Initiative Registry, we identified all patients who had endovascular PVI for occlusive lower-extremity arterial disease from 2010 to 2019. Procedures in which an atherectomy device was recorded as the primary or secondary device were classified as the atherectomy group. We calculated frequency of atherectomy use over time and across geographic regions. Using regression modeling, we identified factors that were independently associated with atherectomy use.

RESULTS

There were 205,377 procedures on 152,693 unique patients. Over 10 years, 16.6% of PVI procedures used atherectomy, increasing from 8.5% in 2010 to 19.7% in 2019, P_trend <0.0001. Across 17 geographic regions, there was a significant difference in the prevalence of atherectomy use, ranging from 8.2% to 29%. The strongest predictor of atherectomy use was the procedure being done in an office setting (OR 10.08, 95% CI 9.17-11.09) or ambulatory center (OR 4.0, 95% CI 3.65-4.39) vs hospital setting. The presence of severe (OR 2.6, 95% CI 2.4-2.85) or moderate (OR 1.5, 95% CI 1.4-1.69) lesion calcification was also predictive of atherectomy use. Other predictors included elective status, insurance provider, lesion length, prior PVI, claudication symptoms, and diabetes mellitus.

CONCLUSIONS

Atherectomy use in PVI significantly increased between 2010 and 2019. There is wide regional variability in the use of atherectomy that seems to be driven more strongly by non-clinical factors.

Review on Laser Technology in Intravascular Imaging and Treatment

Blood vessels are one of the most essential organs, which nourish all tissues in our body. Once there are intravascular plaques or vascular occlusion, other organs and circulatory systems will not work properly. Therefore, it is necessary to detect abnormal blood vessels by intravascular imaging technologies for subsequent vascular treatment. The emergence of lasers and fiber optics promotes the development of intravascular imaging and treatment. Laser imaging techniques can obtain deep vascular images owing to light scattering and absorption properties. Moreover, photothermal and photomechanical effects of laser make it possible to treat vascular diseases accurately. In this review, we present the research progress and applications of laser techniques in intravascular imaging and treatment. Firstly, we introduce intravascular optical coherent tomography and intravascular photoacoustic imaging, which can obtain various information of plaques. Multimodal intravascular imaging techniques provide more information about intravascular plaques, which have an essential influence on intravascular imaging. Secondly, two laser techniques including laser angioplasty and endovenous laser ablation are discussed for the treatment of arterial and venous diseases, respectively. Finally, the outlook of laser techniques in blood vessels, as well as the integration of laser imaging and treatment are prospected in the section of discussions.

Patient-Reported Outcome Measures in Symptomatic, Non-Limb-Threatening Peripheral Artery Disease: A State-of-the-Art Review

Patient-reported outcome measures (PROMs) are health outcomes directly reported by the patient that can be used to measure the effect of disease and treatments on patient perceived well-being. This review summarizes current evidence regarding the validation of PROMs in people with symptomatic, nonlimb-threatening peripheral artery disease. A literature search was conducted to identify studies of symptomatic peripheral artery disease without limb-threatening ischemia that included PROMs and had sample sizes ≥25. PROMs were summarized along a continuum of validation using classical test theory framework and according to whether they fulfilled defined criteria for (1) content validity; (2) psychometric validation; and (3) further validation evidence base expansion. Of 2198 articles identified, 157 (7.1%) met inclusion criteria. Twenty-four PROMs in patients with symptomatic peripheral artery disease were reviewed. Among disease-specific PROMs, 8 of 15 had excellent reliability as measured by a Cronbach alpha ≥0.80. Based on established criteria for PROM responsiveness, 6 of 15 disease-specific PROMs demonstrated excellent sensitivity to change. Of these, the disease-specific peripheral artery questionnaire, vascular quality of life questionnaire, and walking impairment questionnaire met criteria for validation at each stage of the continuum. For generic (nondisease specific) PROMs, the European Quality of Life 5-Dimension and SF-36 had the most extensive evidence of validation. Evidence from this review can inform selection of PROMs aligned with scientific and clinical goals, given the variable degree of validation and potential complementary nature of the measures.

Endovascular treatment of high-risk peripheral vascular occlusive lesions: a review of current evidence and emerging applications of intravascular lithotripsy, atherectomy, and paclitaxel-coated devices

Endovascular treatment of peripheral arterial disease has evolved and expanded rapidly over the last 20 years. New technologies have increased the diversity of devices available and have made it possible to approach even the most challenging and high-risk lesions using endovascular techniques. In this review, we examine the clinical evidence available for several categories of endovascular devices available to treat peripheral arterial disease, including intravascular lithotripsy, atherectomy, and drug-coated devices. The best application for some technologies, such as intravascular lithotripsy and atherectomies, have yet to be identified. In contrast, drug-coated devices have an established role in patients at high risk for long-term failure, but have been the subject of much controversy, given recent concerns about possible adverse effects of paclitaxel. Future investigation should further assess these technologies in patients with complex disease using updated staging systems and outcomes with direct clinical relevance, such as functional improvement, wound healing, and freedom from recurrent symptoms.

United States Investigational Device Exemption study of the Revolution™ Peripheral Atherectomy System

OBJECTIVE

Atherectomy has become commonplace as an adjunct to interventional treatments for peripheral arterial disease, but the procedures have been complicated by risks including distal embolization and arterial perforation. This study aimed to examine the safety and effectiveness of a novel atherectomy system to treat femoropopliteal and below-knee peripheral arterial disease.

METHODS

The Revolution Peripheral Atherectomy System (Rex Medical LP, Conshohocken, Pa) was studied in 121 patients with 148 femoropopliteal and below-knee lesions, enrolled at 17 United States institutions. Technical success was defined when the post-atherectomy angiographic stenosis was ≤50%, as assessed by an independent core laboratory. Major adverse events were adjudicated by an independent Clinical Events Committee.

RESULTS

Among 148 site-identified target lesions in 121 patients, 21.4% were in the superficial femoral artery, 13.7% involved the popliteal artery, and 67.9% were in tibial arteries; 3.1% involved more than one segment. Technical success was 90.2%, with stenoses decreasing from 73% ± 19% at baseline to 42% ± 14% after atherectomy. Adjunctive treatment after atherectomy included angioplasty with uncoated balloons in 91%, drug-coated balloons in 11%, bare stent deployment in 8%, and drug-eluting stent placement in 3%. Procedural success (<30% residual stenosis) was achieved in 93.7% of target lesions. Complications during the procedure included one target vessel perforation and two distal embolizations; each of which were adjudicated by the Clinical Events Committee as unrelated to the device and were not visualized angiographically by the core laboratory. Freedom from major adverse events was 97.3% through 30 days. The Kaplan-Meier estimates of primary, assisted primary, and secondary patency were 81.6%, 87.7%, and 91.6% at 6 months, respectively.

CONCLUSIONS

The use of the Revolution Peripheral Atherectomy System was associated with few procedural complications and a high rate of success at the index procedure and through 6 months.

Intravascular Ultrasound Assessment and Correlation With Angiographic Findings of Arterial Dissections Following Auryon Laser Atherectomy and Adjunctive Balloon Angioplasty: Results of the iDissection Auryon Laser Study

BACKGROUND

Femoropopliteal arterial angiographic dissections with the use of the Auryon laser atherectomy system (previously the B-laser) have been infrequent and non-flow limiting. However, the pattern of these dissections (depth and arc) using intravascular ultrasound remains unknown.

MATERIALS AND METHODS

We prospectively enrolled 29 patients in the iDissection Auryon study. The primary objective was to define the occurrence of new adventitial injury with intravascular ultrasound (IVUS). Secondary objectives included distal embolization and bailout stenting as judged by the operator because of 30% or more residual narrowing and/or NHLBI (National Heart, Lung, and Blood Institute) angiographic dissection C and higher. Core laboratory analysis was carried on all cases except for 1 patient (that crossed over to Jetstream atherectomy). Dissections were classified according to the iDissection classification as involving the intima (A), media (B), and adventitia (C) and ≤ 180-° arc (1) or >180-° arc (2). Overall, 22 of 29 patients had an embolic filter (per protocol).

RESULTS

Median lesion and treated lengths were 100.0 and 150.0 mm, respectively. Vessel diameter by IVUS was 6.5 ± 1.5 mm. Chronic total occlusion (CTO) was present in 24.1% of cases. The arc of calcium was: no calcium in 27.6%, <90° in 13.8%, 90° to 180° in 20.7%, and >180° in 34.4%. Lesion severity was reduced to a median of 14% post laser and adjunctive percutaneous transluminal angioplasty (PTA) from a baseline of 76%. Bailout stenting occurred in 6 of 28 (21.4%) patients (3 for dissections, 2 for residual >30%, and 1 for both) and primary stenting in 1 of 28 (3.6%). By IVUS, there were 9 new dissections post laser (1 adventitial; 3≥180°) and 21 new dissections post laser and PTA (3 adventitial; 1≥180°). No distal embolization requiring treatment was seen and no macrodebris ≥2 mm was recovered in the filters.

CONCLUSION

The Auryon laser atherectomy system had minimal rate of adventitial injury despite complex disease with relatively low bailout stent rate and no clinically significant macrodebris.

Tissue post-classification using the measured acoustic signals during 355 nm laser atherectomy procedures

The current laser atherectomy technologies to treat patients with challenging (to-cross) total chronic occlusions with a step-by-step (SBS) approach (without leading guide wire), are lacking real-time signal monitoring of the ablated tissues, and carry the risk for vessel perforation. We present first time post-classification of ablated tissues using acoustic signals recorded by a microphone placed nearby during five atherectomy procedures using 355 nm solid-state Auryon laser device performed with an SBS approach, some with highly severe calcification. Using our machine-learning algorithm, the classification results of these ablation signals recordings from five patients showed 93.7% classification accuracy with arterial vs nonarterial wall material. While still very preliminary and requiring a larger study and thereafter as commercial device, the results of these first acoustic post-classification in SBS cases are very promising. This study implies, as a general statement, that online recording of the acoustic signals using a noncontact microphone, may potentially serve for an online classification of the ablated tissue in SBS cases. This technology could be used to confirm correct positioning in the vasculature, and by this, to potentially further reduce the risk of perforation using 355 nm laser atherectomy in such procedures.

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.