Treatment of infrapopliteal post-PTA dissection with tack implants: 12-month results from the TOBA-BTK study

Comparative Analysis of Mortality and Amputation Rates in Patients Undergoing Atherectomy for Infra-Popliteal Peripheral Arterial Disease: Insight From the VQI

INTRODUCTION

Infra-popliteal peripheral arterial disease (IPPAD) poses challenges due to high restenosis and occlusion rates. The BASIL-2 trial demonstrated the superiority of endovascular treatment compared with surgical bypass in patients with IPPAD. However, the association between different endovascular modalities and clinical outcomes has not been conclusive.

HYPOTHESIS

Combining plain old balloon angioplasty (POBA) with atherectomy is associated with improved clinical outcomes compared with POBA alone.

METHODS

Patients who underwent POBA vs POBA+atherectomy for IPPAD from the Vascular Quality Initiative database were identified. To mitigate potential selection bias, we employed propensity score matching (PSM) to balance the distribution of confounding variables for mortality identified on multivariable logistic regression. Subsequently, we compared patient characteristics and long-term outcomes between the 2 treatment groups.

RESULTS

Among patients who underwent endovascular intervention for IPPAD, 19 979 individuals (80.8%) were treated with POBA alone, while 4747 (19.2%) were treated with both POBA+atherectomy after PSM. Propensity score matching ensured minimal differences in baseline characteristics, such as indication for lower extremity revascularization (LER) and history of LER. After PSM, patients receiving POBA+atherectomy experienced higher rates of technical success and lower perioperative complications, such as renal complications and hematoma, compared with POBA alone. During long-term follow-up, patients who underwent atherectomy had lower rates of major amputation and major adverse limb events (MALE) but slightly lower freedom from reintervention. Nonetheless, there were no differences in mortality.

CONCLUSION

Combining POBA with atherectomy appears to be a safe approach in patients with IPPAD, with lower rates of long-term amputation and MALE at the cost of a higher risk of reintervention.

CLINICAL IMPACT

The use of adjunctive atherectomy is associated with improved long-term outcomes in patients with infra-popliteal disease.

Below-the-Knee Stents and Scaffolds: A Comprehensive Review

Below-the-knee intervention of chronic limb-threatening ischemia is an area of increasing interest. Due to lower morbidity and possibly better clinical outcomes, endovascular techniques have become increasingly important in this patient population many of who have limited surgical options. This article serves as a review of existing stent and scaffolding devices utilized for infrapopliteal disease. The authors will additionally discuss current indications and review studies that are investigating novel materials used in treating infrapopliteal arterial disease.

Twenty-Four Month Results of Tack-Optimized Balloon Angioplasty Using the Tack Endovascular System in Below-the-Knee Arteries

PURPOSE

To report 24 month safety and efficacy of the Tack Endovascular System for treatment of post-percutaneous transluminal angioplasty (PTA) infrapopliteal dissections in patients with critical limb-threatening ischemia (CLTI).

MATERIALS AND METHODS

The Tack-Optimized Balloon Angioplasty (TOBA) II below-the-knee (BTK) study was a prospective, multicenter, single-arm evaluation of the Tack Endovascular system for post-PTA infrapopliteal dissection repair. Patients with Rutherford Clinical Category (RC) 3 to 5 and a post-PTA dissection(s) of the BTK arteries were enrolled. The 30 day primary safety endpoint was a composite of major adverse limb events (MALE) and all-cause perioperative death (POD). The primary effectiveness endpoint was a composite of MALE at 6 months and 30 day POD. Outcomes were assessed as observational endpoints at 24 months.

RESULTS

Tack-Optimized Balloon Angioplasty II BTK enrolled 233 patients; all patients had a post-PTA dissection(s) and received ≥1 Tack implant (range, 1-16). Mean age was 74.4±10.0 years and 67.4% were men. Most patients had CLTI (RC 3: 16.3%; RC 4/5: 83.7%). Mean target lesion length was 80±49 mm. Moderate to severe calcium was present in 89 (35.8%) lesions and total occlusions were present in 118 (47.6%) lesions. Kaplan-Meier freedom from MALE at 24 months + POD at 30 days was 92.2% and 24 month freedom from clinically-driven target lesions revascularization was 73.6%. Kaplan-Meier target limb salvage was 95.7% and amputation-free survival was 75.4%. Improvements in functional status and quality of life were observed through 24 months.

CONCLUSION

The TOBA II BTK study demonstrated sustained safety and efficacy through 24 months in patients treated for post-PTA dissection(s) of BTK lesions.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02942966.

Device profile of the tack endovascular system® for the treatment of peripheral arterial disease: overview of safety and efficacy

Introduction: The 6 F Tack Endovascular System® is approved by the United States Food and Drug Administration (FDA) for post-percutaneous transluminal angioplasty (PTA) dissection repair in the superficial femoral and proximal popliteal arteries, and the 4 F System for post-PTA dissection repair in the mid/distal popliteal, peroneal and tibial arteries. The latter is the first FDA approval for an infra-popliteal implantable device.Areas covered: An evaluation of the Tack Endovascular System® design and a summary of the current safety and efficacy data.Expert opinion: Endovascular intervention for the treatment of symptomatic peripheral arterial disease (PAD) in the lower extremities is complicated by long-lesion length, extensive calcification and, below the knee, narrow vessel diameter. PTA is a foundational element for the treatment of these lesions and works by causing a controlled dissection and vessel expansion of the target lesion. Occasionally, dissections can extend beyond the target lesion and/or become hemodynamically significant due to lumen impingement necessitating additional intervention. Historically these dissections were treated with the use of stents, prolonged balloon inflation time or went untreated. The Tack Endovascular System® was designed to provide operators a safe and effective device which could repair post-PTA dissections while preserving future treatment options.

Six-month pivotal results of tack optimized balloon angioplasty using the Tack Endovascular System in below-the-knee arteries

OBJECTIVE

No vascular implant is commercially available in the United States to treat post-angioplasty dissections in below-the-knee (BTK) arteries. The Tack Endovascular System (Intact Vascular, Wayne, Pa) is purpose-built to repair postpercutaneous transluminal angioplasty (PTA) BTK dissections. A trial was conducted to investigate the safety and efficacy of the first-of-a-kind implantable BTK device to treat post-PTA dissections in the setting of critical limb ischemia.

METHODS

The present prospective, single-arm, multicenter study evaluated the Tack Endovascular System for treating post-PTA dissections in the mid/distal popliteal, tibial, and peroneal arteries. The primary safety endpoint was major adverse limb events (MALE) plus perioperative death (POD), assessed at 30 days after the index procedure. The primary efficacy endpoint was a composite of MALE at 6 months and POD. The unpowered secondary endpoint was primary patency at 6 months. With no available on-label comparator, the primary endpoints of the present trial were determined using objective performance goals from a systematic literature search. The secondary endpoints included Tacked segment patency and target limb salvage at 6 months. The 6-month results are reported.

RESULTS

Of the 233 patients enrolled, 117 (50.2%) had Rutherford class 5 and 78 (33.5%) had Rutherford class 4. A total of 341 post-PTA dissections were treated. Each patient received at least one Tack implant, and 100% of the dissections resolved according to the angiographic core laboratory findings. The primary safety and efficacy endpoints were both met. The rate of MALE plus POD at 30 days was 1.3% (3 of 228) and freedom from MALE at 6 months plus POD at 30 days was 95.6% (196 of 205). The 6-month Tacked segment patency was 82.1% (247 of 301) and target limb salvage was 98.5% (202 of 205). The Kaplan-Meier freedom from clinically driven target lesion revascularization and amputation-free survival at 6 months was 92.0% and 95.7%, respectively. Rutherford improvement was reported in 79.4% (158 of 199). Most (90 of 122; 73.8%) preexisting wounds had healed or were improving.

CONCLUSIONS

The Tack Endovascular System is safe and effective for treating post-PTA BTK dissections through 6 months, with favorable rates of MALE plus POD, patency, clinically driven target lesion revascularization, limb salvage, and wound healing.

Twelve-Month Results of Tack-Optimized Balloon Angioplasty Using the Tack Endovascular System in Below-the-Knee Arteries (TOBA II BTK)

Purpose: To report the 12-month safety and efficacy outcomes of the investigational device exemption trial evaluating an implantable below-the-knee (BTK) dissection repair device. Materials and Methods: The prospective, multicenter, single-arm Tack-Optimized Balloon Angioplasty (TOBA) II BTK study (ClinicalTrials.gov identifier NCT02942966) evaluated the Tack Endovascular System in the BTK arteries vs objective performance goals derived from a systematic review of BTK angioplasty literature. Patients presenting with Rutherford category 3-5 ischemia were eligible and were enrolled during the procedure if angioplasty resulted in dissection(s) of the BTK arteries. Between February 2017 and December 2018, the study enrolled 233 patients (mean age 74.4±10.0 years; 157 men). Most lesions (93.8%) were de novo; almost half (118/248, 47.6%) were total occlusions. Mean target lesion length was 80±49 mm. Moderate to severe calcium was present in 89 (35.8%) lesions. The 30-day primary safety endpoint was a composite of major adverse limb events (MALE) and all-cause perioperative death (POD). The primary efficacy endpoint was a composite of MALE at 6 months and 30-day POD. These safety and efficacy endpoints were assessed at 12 months as observational endpoints along with amputation-free survival (AFS), freedom from clinically-driven target lesion revascularization (CD-TLR), vessel patency, and changes from baseline in clinical and quality of life measures. Results: All patients had post-PTA dissection and received at least 1 Tack implant (range 1 to 16). The angiographic core laboratory noted successful resolution of 100% of the 341 treated dissections. At 12 months, 93.4% (170/182) of patients remained free of the composite endpoint of MALE + POD. Tacked segment patency was 81.3% and limb salvage was 96.8% at 12 months; freedom from CD-TLR and AFS were 83.1% and 89.3%, respectively. Sustained Rutherford category improvement was reported in 82.4% of evaluated patients, with 62.4% improving ≥3 categories (p<0.001). Ninety of 124 index wounds (72.5%) healed or improved. Conclusion: The Tack Endovascular System is safe and effective in the treatment of post-angioplasty BTK dissections. Twelve-month outcome data from the TOBA II BTK study demonstrate high rates of patency, limb salvage, and wound healing.

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.

New Innovations and Devices in the Management of Chronic Limb-Threatening Ischemia

As the number of patients afflicted by chronic limb-threatening ischemia (CLTI) continues to grow, new solutions are necessary to provide effective, durable treatment options that will lead to improved outcomes. The diagnosis of CLTI remains mostly clinical, and endovascular revascularization remains mostly balloon-based. Multiple innovative techniques and technologies are in development or in early usage that may provide new solutions. This review categorizes areas of advancement, highlights recent developments in the management of CLTI and looks forward to novel devices that are currently under investigation.

Optimal Vessel Sizing and Understanding Dissections in Infrapopliteal Interventions: Data From the iDissection Below the Knee Study

Purpose:

To investigate if imaging with intravascular ultrasound (IVUS) yields a more accurate estimate of vessel diameter and the presence of dissections than angiography after intervention in the infrapopliteal arteries.

Materials and Methods:

A prospective, single-center study enrolled 20 consecutive patients (mean age 74.1±12.4 years; 12 women) with infrapopliteal disease who were treated with percutaneous transluminal angioplasty (PTA; n=10) or orbital atherectomy (OA) followed by PTA (n=10). The majority of patients were hypertensive and half were diabetic. The overall lesion length was 7.3±6.3 cm, and the diameter stenosis was 80.3%±22.1%. The baseline characteristics did not differ between the groups. Vessel diameters were measured using IVUS from the internal elastic lamina (IEL) to the IEL. IVUS was performed at baseline, post PTA or OA, and post OA+PTA. Quantitative vascular angiography (QVA) and IVUS were analyzed by a core laboratory. Dissections on cine images were categorized based on the National Heart Lung and Blood Institute (NHLBI) classification, while the arc and depth were used to characterize dissections on IVUS images.

Results:

Mean vessel diameter by QVA was 2.9±0.6 vs 4.0±1.0 mm by IVUS according to the core laboratory (mean difference 1.1±0.9, p<0.001). On angiography, there were 7 dissections after PTA (6 C, 1 D), 1 dissection after OA (1 B), and 2 dissections after OA+PTA (1 A, 1 B; p=0.028 vs post PTA). IVUS uncovered 3.8 times more dissections than seen on angiography. There were 23 dissections after PTA (18 intima, 3 media, 2 adventitia), 12 dissections after OA (8 intima, 1 media, 3 adventitia), and 11 dissections following OA+PTA (7 intima, 1 media, 3 adventitia; p=0.425 vs PTA). Bailout stenting (all due to angiographic dissections ≥C) was necessary in 6 of the PTA cohort and none of the OA+PTA group.

Conclusion:

In addition to underestimating the infrapopliteal vessel diameter by ~25%, angiography underappreciated the presence and severity of post-intervention dissections vs IVUS, particularly in the OA+PTA group.

High-pressure, non compliant balloon angioplasty for long and calcified infrapopliteal and inframalleolar lesions is feasible

BACKGROUND

To evaluate the safety, feasibility and effectiveness of high-pressure, noncompliant balloon angioplasty in the management of long infrapopliteal calcified lesions.

METHODS

Consecutive patients, presenting with chronic limb-threatening ischemia (CLTI) and long (>100 mm) calcified infrapopliteal lesions who were treated with a high pressure, noncompliant balloon (JADE, OrbusNeich, Hong Kong) between January 2016 and July 2016 were retrospectively analyzed. Angioplasty was performed by inflating the balloon to a pressure of 22 to 24 atm for 90 seconds. Primary outcome was technical success. Secondary outcomes were procedure-related complications, limb salvage, amputation-free survival (AFS), wound healing, overall survival, freedom from clinically driven target lesion reintervention (CD-TLR), and resolution of CLTI at 2 and 3 years.

RESULTS

Overall, 23 lesions in 21 limbs of 20 patients were treated. All patients had tissue loss (Rutherford 5 or 6). The mean lesion length was 374.8 mm. Of all lesions, 56.5% were occlusions, 91.3% were classified as TransAtlantic Inter-Society Consensus (TASC) C and D lesions, and 78.3% had severe calcification classification. Of all lesions, 52.2% extended into the below-the-ankle arteries. Technical success was achieved in 22 lesions (95.7%). There were no procedure-related complications. No bailout stenting was required. At 2 and 3 years, limb salvage was 84.7% and 78.7%, AFS was 71.4% and 56.1%, wound healing was 81.0% and 85.7%, overall survival was 75.0% and 64.3% and freedom from CD-TLR was 77.6% and 63.5%, respectively. Resolution of CLTI without TLR was 81.0% at 2 and 3 years.

CONCLUSIONS

This study is the first to analyze safety and feasibility of a high-pressure, noncompliant balloon for long, calcified infrapopliteal and inframalleolar lesions.

Current developments in endovascular therapy of peripheral vascular disease

More than 200 million people worldwide have peripheral artery disease (PAD) or its most severe manifestation, critical limb ischemia (CLI). While endovascular treatment has become first line therapy in most cases, a number of challenges remain for optimal treatment of femoropopliteal (FP) or infrapopliteal (IP) disease, especially when these lesions are severely calcified, chronic total occlusions (CTOs) or in-stent restenosis (ISR). Continued evolution of technologies has significantly improved the outcomes for endovascular treatment. A number of new devices are in the pipeline right now, including new paclitaxel eluting stents and balloons, intravascular lithotripsy to treat severely calcified lesions, adventitial delivery of anti-restenotic agents to limit restenosis rates, and percutaneous femoro-popliteal bypass.

Practical Applications of Tack Implants for Infrainguinal Dissection Repair: A Single-Center Experience

Purpose: To assess the practical application and acute outcomes of the Tack Endovascular System for infrainguinal dissection repair in a real-world setting. Materials and Methods: Fifty-one consecutive patients who underwent endovascular revascularization for symptomatic peripheral artery disease and experienced 63 dissections requiring treatment were included in the prospective, single-center, single-arm study between January and June 2019. Thirty-nine (76.5%) lesions were ≥10 cm in length, 33 (64.7%) were totally occluded, and 13 (25.5%) were severely calcified. Fifty-six (88.9%) dissections were classified as severe. Dissections were treated either by means of the 6-F above-the-knee (ATK) or the 4-F below-the-knee (BTK) Tack Endovascular System. Observational outcomes were conditions and scopes of application. Clinical outcomes were acute technical and procedural success as well as safety. Results: Lesions were revascularized with 2.3±0.8 attempts such as standard balloon angioplasty, drug-coated balloon angioplasty, atherectomy, and/or lithotripsy. The Endovascular System was applied in 60 (95.2%) of 63 dissections. All dissections of the femoral artery were treated with the ATK system, and all infrapopliteal dissections with the BTK system. Both systems were successfully applied in popliteal artery dissections. Dissection length predicted the number of Tack implants deployed. Technical success was achieved in 98.3% (59 of 60 dissections). No major adverse event or device-related complication occurred during the procedure. Conclusion: Acute results in effectiveness and safety of the Tack Endovascular System for infrainguinal dissection repair in a real-world setting are promising.

Newly approved devices for endovascular treatment of femoropopliteal disease: a review of clinical evidence

Introduction: Femoropopliteal lesions account for a significant proportion of endovascular interventions for peripheral artery disease. In this manuscript, we review the literature on the application of newly approved devices in the treatment of atherosclerotic lesions at this segment.Areas covered: New drug-coating technologies provide sustained drug-eluting over time and better scaffolds are more resistant to the increased biomechanical stress at the femoropopliteal segment. Thus, the newer drug-eluting stents (i.e. Eluvia®), nitinol interwoven stents (i.e. Supera®), and drug-coated balloons (i.e. Stellarex®) are associated with improved pharmacokinetic profiles and promising primary patency rates. A major predictor of technical failure and restenosis is the calcification of the target vessel. Recently, intravascular lithotripsy of calcified lesions at the femoropopliteal segment with the Shockwave® balloon was introduced as a feasible treatment option for these complex lesions. Finally, we also describe the Tack Endovascular System®, the first-of-its-type, for the repair of post-angioplasty dissections.Expert opinion: The use of innovative stent designs and novel drug-coating, the application of adjunctive intravascular lithotripsy, and the combined use of new devices treating complications might improve the overall outcomes of angioplasty, thereby promising favorable outcomes even for more complex 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.

Treatment of infrapopliteal post-PTA dissection with tack implants: 12-month results from the TOBA-BTK study

OBJECTIVES

The Tack implant is designed for focal, minimal metal management of dissections. This study evaluated Tacks for treating postpercutaneous transluminal angioplasty (PTA) dissection in patients with below-the-knee (BTK) arterial occlusive disease.

BACKGROUND

PTA is the most commonly used endovascular treatment for patients with occlusive disease of the BTK vessels. Post-PTA dissection is a significant clinical problem that results in poor outcomes, but currently there are limited treatment options for managing dissections.

METHODS

This prospective, single-arm study evaluated patients with CLI and BTK lesions; 11.4% were Rutherford category (RC) 4 and 88.6% were RC 5. BTK occlusive disease was treated with standard PTA and post-PTA dissections were treated with Tack placement. The primary safety endpoint was a composite of major adverse limb events (MALE) and perioperative death (POD) at 30 days. Other endpoints included: device success; procedure success (vessel patency in the absence of MALE); freedom from clinically driven target lesion revascularization (CD-TLR); primary patency; and changes in RC. Data through 12 months are presented.

RESULTS

Thirty-two of 35 (91.4%) patients had post-PTA dissection and successful deployment of Tacks. Procedural success was achieved in 34/35 (97.1%) patients with no MALEs at 30 days. The 12-month patency rate was 78.4% by vessel, 77.4% by patient, and freedom from CD-TLR was 93.5%. Significant (P < .0001) improvement from baseline was observed in RC (75% of patients improved 4 or 5 steps).

CONCLUSION

Tack implant treatment of post-PTA dissection was safe and effective for treatment of BTK dissections and resulted in reasonable 12-month patency and low rates of CD-TLR.