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

A Laser Atherectomy-Thrombectomy System for Primary Management of Acute Limb Ischemia

PURPOSE

To evaluate the primary use of a laser atherectomy-thrombectomy system in patients with acute limb ischemia (ALI).

MATERIALS AND METHODS

A single-center retrospective review of patients presenting with ALI (≤14 days) from August 2021 to February 2024 treated primarily with a laser atherectomy-thrombectomy system (Auryon; AngioDynamics, Queensbury, New York) was performed. Technical success was defined by resolution of the acute occlusion with adequate inflow and outflow with pedal signals detectable by handheld Doppler ultrasound (US). The primary clinical endpoints were resolution of symptoms without readmission or reintervention in the immediate postprocedural period and at 30 days with follow-up duplex US documenting patency of the treated limb. Twenty-four procedures in 21 patients were included (mean age, 60 years; males:females, 12:9). Seventy-five percent (18/24) of patients presented with Rutherford 1, 12.5% (3/24) presented with Rutherford 2A, and 12.5% (3/24) presented with Rutherford 2B, with a mean symptom duration of 4 days.

RESULTS

Technical success was 92% (22/24) in a single session. Two technical failures required overnight adjuvant thrombolysis. All patients met the immediate postprocedural endpoint, and 92% met the 30-day endpoint. There were no major device-related adverse events or deaths within 30 days, with a major amputation rate of 5%. Distal embolization occurred in 7 (29%) of cases, most of which were focal tibial emboli occurring after adjunctive plain balloon clot maceration and resolved with balloon maceration and/or additional passes of the laser atherectomy-thrombectomy system.

CONCLUSIONS

The use of a laser atherectomy-thrombectomy system is a feasible option as a primary treatment modality for ALI.

An In Vitro Study of 355-nm Laser Ablation of Atherosclerotic Lesions Model

A study of 355 nm laser with high pulse energy across various types of atherosclerotic lesion models is presented. The 355 nm laser pulses (10 ns) are delivered via a single fiber (600 μm diameter), and the ablation of calcified tissue, lipid tissue, and thrombus-like tissue are studied under varied laser fluence (40-70 mJ/mm2) and repetition rate (5-30 Hz). The contact and noncontact ablation processes of chicken tibia samples (calcified tissue) are compared at 60 mJ/mm2 and 30 Hz, and the size of ablation particles is in the range of 0.1-1 μm. At the same repetition rate, the advancement rate of tricalcium phosphate samples reaches 150 μm/s at 70 mJ/mm2. Calcified and lipid models demonstrate predictable increases in ablation with higher laser fluence and repetition rate. The fresh porcine blood clot samples exhibit high-quality ablation with good channel effect at 50 mJ/mm2 and 30 Hz.

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.

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.

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.

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.

JetStream Atherectomy for the Treatment of In-Stent Restenosis of the Femoropopliteal Segment: One-Year Results of the JET-ISR Study

PURPOSE

To report the results of a study evaluating JetStream atherectomy for the treatment of in-stent restenosis (ISR).

MATERIALS AND METHODS

The JetStream XC atherectomy device, a rotational cutter with aspiration capacity, was evaluated in a prospective, multicenter study (JET-ISR) of 60 patients (mean age 70.2±10.8 years; 40 men) with femoropopliteal ISR (ClinicalTrials.gov identifier NCT02730234). Lesion length was 19.9±13.5 cm; 33 (55%) were chronic total occlusions and 26 (45%) were TransAtlantic Inter-Society Consensus class D. No drug-bearing device was allowed, and stenting was performed only for bailout. Lesion characteristics and stent integrity were evaluated by an independent core laboratory. The primary endpoint was target lesion revascularization (TLR) at 6 months with bailout stenting considered as TLR. Secondary endpoints included TLR (without bailout stenting) and clinical patency (no restenosis or TLR) at 1 year. The Kaplan-Meier method was employed to evaluate time-to-event endpoints; estimates are given with 95% confidence interval (CI).

RESULTS

Bailout stenting was required in 6 of 60 limbs (10%). There were no stent fractures or deformities after atherectomy + adjunctive angioplasty reported by the core laboratory. Kaplan-Meier estimates of freedom from TLR at 6 months and 1 year were 79.3% (95% CI 68.9% to 89.8%) and 60.7% (95% CI 47.8% to 73.6%), respectively. When bailout stenting at the index procedure was not considered a TLR event, freedom from TLR estimates at 6 months and 1 year were 89.3% (95% CI 81.2% to 97.4%) and 66.8% (95% CI 54.3% to 74.2%), respectively. Clinical patency rates at 6 months and 1 year were 77.5% (31/40) and 51.7% (15/29), respectively.

CONCLUSION

JetStream atherectomy using the XC device and no drug-eluting devices is feasible, with good clinical patency and 1-year freedom from TLR.

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.