Adjunctive Utilization of Intravascular Ultrasound in Peripheral Arterial Disease Treatment

BACKGROUND

The utility and benefit of intravascular ultrasound (IVUS) has been well established in coronary interventions, however widespread adoption for peripheral interventions has lagged. The objectives of this review article were to discuss the technical components of IVUS, describe key learning pearls for IVUS utilization, and review the literature describing the clinical outcomes of endovascular peripheral arterial interventions using IVUS.

METHODS

A scoping review of the current literature utilizing Pubmed. Terms used to search the literature included "intravascular ultrasound (IVUS)" in conjunction with "peripheral arterial disease (PAD)," "endovascular interventions," "chronic limb threatening ischemia," "balloon angioplasty" "stenting," "percutaneous coronary intervention," and "outcomes." All types of articles were reviewed including review articles, retrospective reviews, meta-analyses, and prospective observational and randomized studies.

RESULTS

Published literature regarding IVUS use in peripheral arterial interventions is heterogeneous and limited to mainly retrospective studies, registry analyses and metanalyses. Outcomes are generally favorable with the adjunct of IVUS compared to traditional angiography-driven peripheral interventions. The addition of IVUS improves stent expansion, stent patency, and reduces reintervention rates, particularly in infrainguinal arterial lesions. Long-term costs may also be lower with IVUS-guided procedures.

CONCLUSIONS

Expert consensus largely supports the implementation of IVUS in endovascular interventions for peripheral arterial disease. However, more robust high-quality data evaluating the efficacy, durability, and cost of IVUS in peripheral arterial disease are still needed.

Intravascular Ultrasound-Guided Versus Angiography-Guided Endovascular Therapy for Femoropopliteal Artery Disease: A Scoping Review

OBJECTIVE

The objective of this study was to summarize whether the application of additional intravascular ultrasound (IVUS) can change the outcomes of endovascular treatment in femoropopliteal atherosclerotic lesions compared with conventional angiography alone based on the existing study and evidence.

METHODS

Studies published until September 2022 were searched from PubMed, Embase, and Cochrane databases using the methods of combination of Medical Subject Headings and free text words. The outcomes included in these studies were primary patency rate or restenosis rate and freedom from clinically driven target lesion revascularization (cdTLR) rate, and most studies were concerned about the 12-month results. Two independent authors conducted the process of study selection. And the pooled analysis was attempted.

RESULTS

Finally, the inclusion criteria were met by 4 studies (1 randomized controlled trial and 3 retrospective studies) involving 1160 patients. IVUS played its role in measuring lesions and/or guiding wiring passage. Most of the included studies showed that IVUS could achieve a higher 12-month primary patency rate (from 70% to 90%) and higher 12-month freedom from cdTLR rate (from 83.9% to 94.7%) than angiography. The tentative pooled analysis also showed that IVUS significantly improved the 12-month primary patency rate (OR: 2.21, 95%CI: [1.38-3.55], p=0.001) and the 12-month freedom from cdTLR rate (OR: 1.70, 95%CI [1.04-2.78], p=0.03) compared with angiography alone.

CONCLUSIONS

Intravascular ultrasound-guided endovascular treatment of femoropopliteal artery lesions may have its own advantages such as higher primary patency rate and freedom from cdTLR rate at 12 months. As a novel technology, IVUS is expected to become another beneficial option to guide clinicians performing endovascular therapy in addition to angiography and may achieve better clinical outcomes. More prospective and high-quality studies are needed in the future to investigate the role of IVUS in the process of femoropopliteal artery lesions endovascular treatment.

CLINICAL IMPACT

This review summarized a few available studies to promote understanding of IVUS and reveal its potential. This novel technology shows the possibility of achieving better clinical outcomes than angiography in femoropopliteal artery lesions endovascular therapy such as higher 12-month primary patency rate shown in some studies. Currently, it is important to consider suitable technologies applied to individualized treatment. IVUS seems to provide clinicians additional option in clinical practice and benefit patients well in the future. And it needs us to conduct more high-quality studies to explore its roles and advantages in endovascular treatment.

Predictors of recurrence based on intravascular ultrasound findings after Eluvia placement in symptomatic peripheral arterial disease: A retrospective study

Background and Aims

Polymer-coated drug-eluting stents (Eluvia) have shown favorable clinical outcomes in real-world registries. There are no reports on recurrent predictors after Eluvia placement based on intravascular ultrasound (IVUS) findings.

Methods

We analyzed clinical data from the ASIGARU PAD registry, a retrospective, multicenter, observational study that enrolled patients who underwent endovascular therapy for superficial femoral and proximal popliteal arteries lesions using Eluvia or drug-coated balloon. The primary outcome was the identification of recurrent predictors, including IVUS parameters at 12 months. The rate of target lesion recurrence was also assessed.

Results

IVUS images were obtained in 54 of 65 cases. Seven recurrent cases (13.0%) were observed within 12 months. The random survival forest method presented eight predictive variables of recurrence: Clinical Frailty Scale (CFS), distal stent edge area, distal plaque burden, age, sex, distal external elastic membrane (EEM) area, minimum stent area (MSA), and distal lumen area. Furthermore, the partial dependence plot showed that frailty (CFS ≥ 6), smaller distal stent edge area, higher and lower distal plaque burden, older and younger age, female sex, smaller distal EEM area, smaller MSA, and smaller and larger distal lumen area predicted recurrence after Eluvia placement within 12 months.

Conclusion

CFS, distal stent edge area, distal plaque burden, age, sex, distal EEM area, MSA, and distal lumen area were significant recurrent predictors after Eluvia placement.

Intravascular ultrasound guidance for lower extremity arterial and venous interventions

This review details the utility of intravascular ultrasound (IVUS) for the management of peripheral artery and venous disease. The purpose of this document is to provide an update in the use of IVUS in peripheral arterial and venous pathology and demonstrate the use of IVUS as a practical diagnostic imaging procedure to evaluate and treat peripheral vascular disorders. IVUS, a diagnostic tool that relies on sound waves to produce precise images of the vessel being evaluated, was originally introduced to the medical community for the purposes of peripheral artery imaging, though it was quickly adapted for coronary interventions with positive outcomes. The utility of IVUS includes vessel measurement, pre- and post-procedural planning, treatment optimisation, and detection of thrombus, dissection or calcium severity. While angiography remains the standard imaging approach during peripheral intervention, multiple observational studies and small prospective trials have shown that in comparison, IVUS provides more accurate imaging detail, which may improve procedural outcomes. IVUS can also address limitations of angiography, including the need to administer contrast medium and eliminate the ambiguity associated with other forms of imaging. This review provides contemporary examples of where IVUS is being used during peripheral intervention as well as representative imaging to serve as a resource for the practising clinician.

The safety and efficacy of different endovascular treatments for in-stent restenosis of the femoropopliteal artery: A network meta-analysis

Purpose: Femoropopliteal artery in-stent restenosis (ISR) remains a challenging treatment. We performed a network meta-analysis (NWM) for femoropopliteal artery ISR to explore the safety and efficacy of endovascular therapeutic strategies. Methods: The MEDLINE, Embase, Web of Science, and Cochrane databases were used as data sources. The network meta-analysis (NWM) approach used random-effects models based on the frequentist framework. We compared technical success rate, primary patency, target lesion revascularization (TLR), and major amputation at the 12-month follow-up for femoropopliteal artery ISR. Results: In total, 14 eligible studies (10 prospective and four retrospective; 1348 patients; and eight treatment modalities - standard balloon angioplasty (SBA), drug-coated balloon (DCB), peripheral cutting balloon angioplasty (PCBA), Viabahn endoprosthesis (VBE), directional atherectomy (DA), excimer laser atherectomy (ELA), and combinations - were included. The primary patency rates (at 6 months) were significantly higher for DCB and ELA+DCB than for SBA and ELA+SBA. ELA+DCB had higher primary patency rates (at 12 months) than ELA+SBA and SBA. The technical success rates were significantly lower for DCB and SBA than for VBE. The major amputation rates were significantly lower for ELA+DCB than for DCB. Based on the surface values under the cumulative ranking curve (SUCRA), ELA+DCB was considered the best treatment in terms of primary patency at 6 months (SUCRA = 91.1), primary patency at 12 months (SUCRA = 82.3), and TLR (SUCRA = 83.4). Conclusion: ELA+DCB showed positive encouraging results in primary patency (6, 12 months), TLR, and major amputation in femoropopliteal ISR. The efficacy and safety of ELA+DCB are worthy of further investigation. (PROSPERO Registration No.: CRD42021246674).

Predictability and usefulness of intravascular ultrasound-guided angioplasty in patients with femoropopliteal lesions: a systematic review and meta-analysis

INTRODUCTION

To assess whether intravascular ultrasound (IVUS)-guided angioplasty in femoropopliteal lesions would improve clinical outcomes and predict restenosis.

EVIDENCE ACQUISITION

Studies in which IVUS-guided angioplasty was used for femoropopliteal lesions were searched from the MEDLINE, Embase, Web of Science, and Cochrane databases; articles with the full text were included. The primary endpoint of this study was primary patency at 12 months, while the secondary endpoints were primary patency at 24 months, freedom from target lesion revascularization (TLR) at 12 months, and correlation of restenosis with the distal external elastic membrane (EEM) area, post-intervention minimum lumen area, lesion length, dissection, and calcification.

EVIDENCE SYNTHESIS

Altogether, 11 observational studies involving 1521 patients (1703 lesions) were analyzed. The quality of the evidence for 7 main outcomes was assessed as "very low" by The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) classification. The mean follow-up period was 1.5 years. The pooled rates were: 78% for 12-month primary patency (95% confidence interval [CI], 0.72-0.83), 74.3% for 24-month primary patency (95% CI, 0.71-0.78), and 80% for 12-month freedom from TLR (95% CI, 0.74-0.86). The 12-month primary patency of IVUS use (relative risk [RR], 2.01; 95% CI, 1.48-2.74) was higher compared to non-IVUS use. The minimum lumen (stent) area (standard mean difference (SMD) = -0.30; 95% CI, -0.46 to -0.15) and dissection (OR 1.58; 95% CI, 1.01-2.49, P = 0.047), were associated with midterm patency in terms of restenosis.

CONCLUSIONS

In IVUS-guided angioplasty in patients with femoropopliteal lesions, the minimum lumen (stent) area and dissection were associated with restenosis. Nevertheless, there is limited and heterogeneous evidence regarding the usefulness and Predictability of IVUS in patients with peripheral arterial disease in the femoropopliteal artery, especially in long-term patency and as a predictor of declining patency. The optimal role of IVUS in such patients should be elucidated in the future.

Advances in Revascularization for Peripheral Artery Disease: Revascularization in PAD

Effective revascularization of the patient with peripheral artery disease is about more than the procedure. The approach to the patient with symptom-limiting intermittent claudication or limb-threatening ischemia begins with understanding the population at risk and variation in clinical presentation. The urgency of revascularization varies significantly by presentation; from patients with intermittent claudication who should undergo structured exercise rehabilitation before revascularization (if needed) to those with acute limb ischemia, a medical emergency, who require revascularization within hours. Recent years have seen the rapid development of new tools including wires, catheters, drug-eluting technology, specialized balloons, and biomimetic stents. Open surgical bypass remains an important option for those with advanced disease. The strategy and techniques employed vary by clinical presentation, lesion location, and lesion severity. There is limited level 1 evidence to guide practice, but factors that determine technical success and anatomic durability are largely understood and incorporated into decision-making. Following revascularization, medical therapy to reduce adverse limb outcomes and a surveillance plan should be put in place. There are many hurdles to overcome to improve the efficacy of lower extremity revascularization, such as restenosis, calcification, microvascular disease, silent embolization, and tools for perfusion assessment. This review highlights the current state of revascularization in peripheral artery disease with an eye toward technologies at the cusp, which may significantly impact current practice.

Usefulness of ultrasound-guided intraluminal approach for long occlusive femoropopliteal lesion

To investigate the usefulness of ultrasound-guided (USG) intraluminal approach for femoropopliteal (FP) lesion. 64 patients (73 limbs) with de novo long occlusive (> 15 cm) FP lesions underwent USG intralumial approach from April 2012 to October 2016. Periprocedural intravascular ultrasound findings were collected. Clinical outcome and predictors of restenosis after USG intraluminal approach for de novo long occlusive FP lesion were investigated. Among the study participants, 34% were female, 50% had diabetes mellitus, and 10% received hemodialysis. Lesion and chronic total occlusion (CTO) lengths were 222 ± 55 mm and 201 ± 55 mm, respectively. Procedural success was achieved in 72 lesions (99%). Distal puncture was performed in 7 limbs (10%). The proportion of within-CTO intraplaque, subintimal, and medial routes were 87 ± 21%, 9 ± 15%, and 4 ± 11%, respectively. Primary patency was 71% and 69% at 1 and 2 years. Multivariate analysis revealed that within-CTO intraplaque route proportion [hazard ratio (HR) 0.81; 95% confidence interval (CI) 0.67-0.98, p = 0.0339] and lesion length (HR 1.11; CI 1.00-1.22; p = 0.0447) were independent predictors of restenosis.USG intraluminal approach facilitated acquisition of within-CTO intraplaque route in long occlusive FP lesions and could improve clinical outcome.

Intravascular Ultrasound Imaging During Aortoiliac Stenting: No Impact on Outcomes at 1 Year

PURPOSE

To investigate the effect of intravascular ultrasound (IVUS) imaging use on clinical outcomes after aortoiliac stenting in patients with peripheral artery disease (PAD).

MATERIALS AND METHODS

Subjects for this retrospective analysis were derived from the OMOTENASHI registry database, which contained 803 symptomatic PAD patients (Rutherford categories 2-4) who were treated with self-expanding stent implantation for aortoiliac atherosclerotic lesions at 61 centers in Japan between January 2014 and April 2016. Of the 803 patients, 545 (67.9%) patients (mean age 73±9 years; 453 men) underwent IVUS-supported stent implantation and were compared with the 258 patients (mean age 73±8 years; 217 men) treated without IVUS. A propensity score analysis of 138 matched pairs was conducted to compare treatment strategies and clinical outcomes between patients having IVUS-supported endovascular therapy and those treated without IVUS.

RESULTS

Endovascular strategies and postoperative medications were not significantly different between the IVUS and no-IVUS groups. A procedure time under 1 hour was less frequent in the IVUS group, which had a longer fluoroscopy time. The 12-month restenosis rate was not significantly different between the 2 groups [10.2% (95% CI 6.9 to 14.9%) vs 10.3% (95% CI 5.4 to 18.6%), p=0.99]. There was no interaction between baseline characteristics and the association of IVUS use with restenosis risk.

CONCLUSION

Propensity score matching analysis revealed that duration and fluoroscopy time during IVUS-supported procedures were significantly longer than in cases without IVUS use, whereas the 12-month restenosis rate was not significantly different between the groups. IVUS use in aortoiliac lesions may be unnecessary.

Differences in Intravascular Ultrasound Measurement Values Between Treatment Modalities for Restenosis in Femoropopliteal Lesions

BACKGROUND

The risk of restenosis after intervention is higher in femoropopliteal than in aortoiliac lesions. However, the appropriate endovascular therapy (EVT) for preventing restenosis after intervention for femoropopliteal lesions remains unknown. This study aimed to elucidate the relationship between lesion characteristics and patency after EVT using intravascular ultrasound (IVUS) measurement and to determine the predictors of restenosis on IVUS.Methods and Results:This prospective observational study was performed at 18 Japanese centers. We evaluated the lesion characteristics before and after EVT for femoropopliteal lesion using IVUS. Angiographic or duplex ultrasound follow-up was performed at 1 year after EVT. A total of 263 lesions underwent EVT between December 2016 and December 2017. In total, 20 lesions (8 cases of isolated common femoral artery lesion and 12 cases of restenosis lesion) were excluded, and 243 lesions were enrolled in this study. A total of 181 lesions were treated with stent placement, and 62 lesions were treated only with balloon angioplasty. In the case of stent use, a larger distal plaque burden was associated with restenosis, while a lower calcification angle was associated with higher patency in the case of balloon angioplasty alone.

CONCLUSIONS

The factors related to patency differed depending on the treating modality. The findings suggest that IVUS is a useful tool for predicting patency because it can provide a more accurate evaluation after EVT for femoropopliteal lesions.

IVUS-Guided Wiring Improves the Clinical Outcomes of Angioplasty for Long Femoropopliteal CTO Compared with the Conventional Intraluminal Approach

AIMS

This study aimed to assess the clinical efficacy of intravascular ultrasound (IVUS)-guided intraplaque wiring for femoropopliteal (FP) chronic total occlusion (CTO).

METHODS

This single-center, retrospective, observational study was performed at the Japanese Red Cross Kyoto Daini Hospital. From March 2013 to June 2017, a total of 75 consecutive patients (mean age: 75.4±8.5 years; 59 males), who underwent endovascular treatment (EVT), having 82 de novo FP-CTO lesions, were enrolled in this study. Eleven of the lesions that met the exclusion criteria were excluded, and the remaining 71 lesions were divided into the IVUS-guided wiring group (n=34) and non-IVUS-guided wiring group (n=37). Primary patency, defined as a peak systolic velocity ratio of ＜2.4 on duplex ultrasonography, and freedom from clinically driven target lesion revascularization (CD-TLR) at 12 months were the primary outcomes.

RESULTS

The mean lesion length was 21.6±8.9 cm. The frequencies of primary patency and freedom from CD-TLR were significantly higher in the IVUS-guided wiring group than in the non-IVUS-guided wiring group (70.0% vs. 52.2%, p=0.045; 83.9% vs. 62.8%, p=0.036, respectively). The complete clinically true lumen angioplasty rate was also higher in the IVUS-guided wiring group than in the non-IVUS-guided wiring group (91.1% vs. 51.3%, p＜0.001, respectively). The clinically true and false wire passage rates were respectively 97.3% and 2.7% in the IVUS-guided wiring group.

CONCLUSION

IVUS-guided wiring improves the clinical outcomes of EVT for FP-CTO by achieving a high clinically true lumen wire passage rate.

Combination therapy of heparin-bonded covered stent and bare-nitinol stent assessed by intravascular ultrasound

To examine clinical outcomes for combination therapy of heparin-bonded covered stent [VIABAHN™ stent (VIA)] and bare-nitinol stent (BNS), and to determine independent predictors of restenosis after VIA implantation assessed by intravascular ultrasound (IVUS). A retrospective analysis was conducted on VIA use in the femoropopliteal artery of 71 patients (81 lesions) treated between June 2012 and November 2018. We divided the treated lesions into two groups; that is, whether BNS was added at the proximal site of the VIA or not (combination of VIA and BNS group [COM; n = 21] vs. VIA group [n = 60]). The median follow-up duration was 21.6 months (interquartile range, 13.2-28.8 months). Restenosis at 2 years was observed in 5 lesions (33%) in COM group and 17 lesions (38%) in VIA group (log-rank, P = 0.74). In VIA group, 14 lesions developed restenosis within 12 months. Multivariate logistic regression analysis of VIA group revealed that the proximal plaque burden was an independent predictor of restenosis within 12 months after VIA implantation (odds ratio 1.15, 95% confidence interval 1.01-1.30, P = 0.01), with the optimal cutoff value of 43% (area under the receiver operator characteristic curve 0.79, sensitivity 91%, specificity 69%). A remaining plaque of > 43% at the proximal reference segment was an independent predictor of restenosis after VIA implantation. When residual stenosis is observed at the proximal site of SFA after VIA implantation, combination therapy of VIA and BNS would be an optimal management.

A post-market, multi-vessel evaluation of the imaging of peripheral arteries for diagnostic purposeS comparing optical Coherence tomogrApy and iNtravascular ultrasound imaging (SCAN)

Background

Intravascular imaging plays an important part in diagnosis of vascular conditions and providing insight for treatment strategy. Two main imaging modalities are intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The objective of this study was to prove non-inferiority of OCT imaging to IVUS images in matched segments of peripheral vessels in patients with suspected peripheral vascular disease.

Methods

The SCAN study was a prospective, non-inferiority clinical study of matched IVUS and OCT images collected along defined segments of peripheral vessels from twelve subjects (mean age 68 ± 10.3 years; 10 men) displaying symptoms of vascular disease. Luminal diameters were measured by both imaging systems at the distal, middle, and proximal points of the defined segments. Three blinded interventional radiologists evaluated the quality of both imaging modalities in identifying layered structures (3-point grading), plaque (5-point grading), calcification (5-point grading), stent structure (3-point grading), and artifacts (3-point grading) from 240 randomly ordered images. Mean grading scores and luminal diameters were calculated and analyzed with Student’s t-Test and Mann-Whitney-Wilcoxon testing. Intrareader reproducibility was calculated by intraclass correlation (ICC) analysis.

Results

The mean scoring of plaque, calcification, and vascular stent struts by the three readers was significant better in terms of image quality for OCT than IVUS (p < 0.001, p = 0.001, p = 0.004, respectively). The mean scores of vessel wall component visibility and artifacts generated by the two imaging systems were not significantly different (p = 0.19, p = 0.07, respectively). Mean vessel luminal diameter and area at three specific locations within the vessels were not significantly different between the two imaging modalities. No patient injury, adverse effect or device malfunction were noted during the study.

Conclusions

Imaging by OCT provides the physician with better visualization of some vessel and plaque chacteristics, but both IVUS and OCT imaging are safe and effective methods of examining peripheral vessels in order to perform diagnostic assessment of peripheral vessels and provide information necessary for the treatment strategy of peripheral artery disease.

Trial registration

NCT03480685 registered on 29 March 2018.

Lumen Gain After Endovascular Therapy in Calcified Superficial Femoral Artery Occlusive Disease Assessed by Intravascular Ultrasound (CODE Study)

Purpose: To assess calcium patterns in superficial femoral artery (SFA) disease before and after balloon angioplasty ± stent implantation using fluoroscopy, angiography, and intravascular ultrasound (IVUS) imaging and then correlate calcification severity and midterm clinical outcomes. Materials and Methods: A multicenter investigation was carried out to retrospectively review 130 symptomatic patients (mean age 73.2±8.4 years; 86 men) with de novo SFA lesions who had successfully undergone endovascular therapy (EVT) at 7 centers between January and October 2015. The primary outcome was lumen gain measured as minimum lumen area (MLA) in post-EVT IVUS images according to calcification severity. The secondary outcomes included rates of stent malapposition, restenosis, and clinically-driven target lesion revascularization (TLR). Results: A total of 102 (78.5%) cases had calcification in the lesions over a mean length of 64.3±72.8 mm. Of these, 70 cases were classified as having bilateral calcification according to fluoroscopy and angiography; 50 (49%) lesions had ≥180° calcification according to IVUS. The lumen gain in calcified lesions was significantly smaller than in the 28 noncalcified lesions (14.1±4.4 vs 17.8±5.2 mm2, p<0.001). IVUS-evaluated circumferential distribution of calcium (<180° or ≥180°) was independently associated with lumen gain after EVT (p<0.001). Among the calcification characteristics, a calcification angle ≥180° showed the strongest correlation to postprocedure MLA. Moreover, the restenosis rate was significantly higher in the severe (≥180°) calcification group (p<0.018). The severity of calcification was also associated with the risk of stent malapposition (p=0.022 for trend) but not TLR (p=0.57). Conclusion: IVUS evaluation of calcification in SFA lesions predicted lumen gain after EVT. Severe calcification in a ≥180° arc prevented successful dilation of the lesion with either plain balloon angioplasty or a nitinol stent. Accurate assessment of calcification patterns by IVUS is useful in maximizing the efficacy of endovascular therapy.

Intravascular ultrasound guided directional atherectomy versus directional atherectomy guided by angiography for the treatment of femoropopliteal in-stent restenosis

BACKGROUND

The aim of this study was to compare 1-year outcomes for patients with femoropopliteal in-stent restenosis using directional atherectomy guided by intravascular ultrasound (IVUS) versus directional atherectomy guided by angiography.

METHODS AND RESULTS

This was a retrospective analysis for patients with femoropopliteal in-stent restenosis treated with IVUS-guided directional atherectomy versus directional atherectomy guided by angiography from a single center between March 2012 and February 2016. Clinically driven target lesion revascularization was the primary endpoint and was evaluated through medical chart review as well as phone call follow up.

CONCLUSIONS

Directional atherectomy guided by IVUS reduces clinically driven target lesion revascularization for patients with femoropopliteal in-stent restenosis.

Percutaneous Therapies for Peripheral Artery Disease

Percutaneous therapies for peripheral artery disease continue to evolve with new techniques and devices. Although guidelines-recommended therapies have impacted cardiovascular morbidity and mortality, endovascular interventions have been shown to reduce limb pain, improve quality of life, and prolong walking distance for those with claudication and to reduce amputation rates among those with critical limb ischemia. Novel devices such as drug-eluting stents and drug-coated balloons have improved patency for moderate-length lesions, whereas others allow treatment of heavily calcified and tortuous segments. New adjunctive devices to cross lesions and reduce or modify associated plaque have also been developed, although level 1 data regarding their efficacy are sparse. There has also been a better mechanistic understanding of lower extremity endovascular treatment using tools such as intravascular ultrasound. This information has highlighted the need for better stent size selection for the femoropopliteal arterial segments and larger balloon diameters for the tibial arteries. Moreover, a wound perfusion approach with direct in-line flow, the so-called angiosome approach, and reconstruction of the pedal loop have been advocated for improved wound healing. Technical advances such as the tibiopedal access and reentry methods have allowed crossing of lesions that were considered no option for the endovascular approach in the past. Collectively, there has been increased awareness, interest, and commitment by various specialty societies and organizations to advance the treatment of peripheral artery disease and critical limb ischemia. This is also evident by the recent coalition of 7 professional societies and organizations that represented >150 000 allied health professionals and millions of patients with peripheral artery disease at the 2015 Centers for Medicaid and Medicare Services Medicare Evidence Development and Coverage Analysis Committee meeting. The percutaneous therapies for peripheral artery disease continue to evolve with longer follow-up with randomized data and larger prospective registries. In the future, it is hopeful that we will treat the lower extremity arteries according to segments, taking into account plaque morphology, luminal versus subintimal crossing, location, and stenotic versus occlusive disease. Until then, we must identify the most cost-effective, efficacious, and safe treatment for each patient. The goal of this article is to aid the practicing vascular specialist consider the optimal choices for the management of patients with vascular disease.

Penetration rate of the placement of a drug-eluting stent for the treatment of superficial femoral artery lesions in Japan

Stent placement for treating superficial femoral artery (SFA) lesions has been approved. The Zilver PTX stent, a drug-eluting stent (DES) for treating SFA lesions, has been available in Japan since 2012. However, the penetration rate of this DES has not yet been reported. This prospective multicenter registry study enrolled 314 patients (354 limbs) to be treated by stent placement in 2014 (UMIN000011551). The primary endpoint was the measurement of the penetration rate of the DES. The secondary endpoints were measuring the freedom from restenosis, freedom from target lesion revascularization (TLR), freedom from major adverse limb event (MALE), and the survival rate at 12 months postoperatively. Female patients comprised 28% participants. The mean age was 73.1 ± 9.2 years. A total of 56% patients had diabetes mellitus (DM), 36% patients were receiving hemodialysis, and 30% used cilostazol at baseline. The mean lesion length was 156 ± 101 mm, and the percentage of TASC II C/D lesions was 58%. Critical limb ischemia (CLI) was observed in 32% limbs. The penetration rates of the Zilver PTX stent were only 8%. The primary patency rate was similar between DES and bare-metal stents (BMS) at 12 months postoperatively (77 vs. 84%, p = 0.52). In this study, the rates of freedom from restenosis, freedom from TLR, freedom from MALE, and the survival rate at 12 months postoperatively were 83, 86, 85, and 89%, respectively. The penetration rate of a first-generation DES placement for treating SFA lesions is low in Japan. On the other hand, BMS is well utilized and its primary patency is acceptable.

FD-OCT and IVUS intravascular imaging modalities in peripheral vasculature

Intra-Vascular Ultra-Sound (IVUS) and Frequency Domain-Optical Coherence Tomography (FD-OCT), in vivo, intra-vascular, imaging modalities, widely used in the field of coronary disease, have been recently implemented in peripheral endovascular procedures, for procedural assessment, plaque characterization and determination of predictors of treatment outcomes. Their unique characteristics have also been used in order to provide additional features and improve the performance of re-entry devices and atherotomes. Areas covered: Present review focuses on available literature regarding these two promising imaging technologies in the peripheral vasculature, highlighting the added value produced by their use in endovascular therapy, their limitations and their utilization in new endovascular devices. Authors also provide their future perspective and the possible benefits in understanding vascular behavior and lesion characterization in peripheral endovascular interventions. Expert commentary: By providing both quantitative but also qualitative data on vessel and lesion morphology, intravascular imaging modalities offer a valid solution for endovascular treatment evaluation and outcome presentation homogeneity.

Clinical Outcomes of the Intraluminal Approach for Long Occlusive Femoropopliteal Lesions Assessed by Intravascular Ultrasound

Aim: To investigate the relationship between intravascular ultrasound (IVUS) findings and restenosis after stent implantation for long occlusive femoropopliteal (FP) lesions using the intraluminal approach.

Methods: This was a single-center retrospective study of 45 patients (49 lesions) with de novo long occlusive FP lesions treated with bare metal stents implanted using the intraluminal approach under IVUS guidance from April 2007 to December 2014. All patients were followed up at least 12 months. The preprocedural and postprocedural IVUS findings were compared for patients with and without restenosis, which was defined as a peak systolic velocity ratio of > 2.4 on duplex ultrasonography or > 50% diameter stenosis on angiography.

Results: Within 12 months, 13 patients (14 lesions) developed restenosis, whereas 32 patients (35 lesions) did not (restenosis rate = 29%). The male:female ratio and the prevalence of diabetes mellitus, hemodialysis, and critical limb ischemia were similar between the two groups. No significant differences were observed in lesion length, chronic total occlusion (CTO) length, and the percentage of involving popliteal lesion between the two groups. A whole intraplaque route was gained in 15 lesions (31%). Multivariate analysis revealed that the within-CTO intramedial route proportion and the distal lumen cross-sectional area (CSA) were independent predictors of restenosis. Receiver operating characteristic analysis showed that the best cutoff values of these parameters were 14.4% and 17.7 mm², respectively.

Conclusions: In patients with long occlusive FP lesions undergoing stent placement using the intraluminal approach, a whole intraplaque route was gained in 31%. Restenosis is more likely if IVUS shows a within-CTO intramedial route proportion of > 14.4% or distal lumen CSA of < 17.7 mm².

Ability of Fractional Flow Reserve to Predict Restenosis After Superficial Femoral Artery Stenting

PURPOSE

To evaluate the clinical efficacy of poststenting fractional flow reserve (FFR) in terms of predicting restenosis in superficial femoral artery (SFA) disease.

METHODS

This prospective, single-center, nonrandomized study enrolled 48 patients (mean age 76±9 years; 38 men) with 51 SFA lesions from July 2013 to June 2014. Mean FFR (distal mean pressure/proximal mean pressure) and systolic FFR (distal systolic pressure/proximal systolic pressure) were calculated, and the relationship between these FFR values and restenosis at 12 months was investigated using receiver operating characteristic (ROC) curve analysis.

RESULTS

Poststenting FFR was significantly lower in the restenosis group (poststenting mean FFR 0.85±0.07 vs 0.93±0.05, p=0.001; poststenting systolic FFR 0.76±0.14 vs 0.87±0.08, p=0.015). The area under the ROC curve for restenosis in poststenting mean FFR was higher, but not statistically significant, than that in poststenting systolic FFR (0.84 vs 0.74, p=0.08). The best poststenting mean FFR cutoff value for predicting restenosis was 0.92 (sensitivity 0.64, specificity 0.91). The 4.5% restenosis rate at 12 months in the high (>0.92) poststenting mean FFR group was significantly lower (35.7%, p=0.008) than in the low (≤0.92) poststenting mean FFR group.

CONCLUSION

Poststenting mean FFR is useful for predicting restenosis in SFA disease.

Treatment of the femoropopliteal artery with the bioresorbable REMEDY stent

OBJECTIVE

Bioresorbable stents are an emerging technology in the endovascular treatment of femoropopliteal lesions. They address the issue of leaving permanent stents in the treated arterial segment that are only temporarily needed to treat dissection or recoil. The REMEDY stent (Kyoto Medical Planning Co, Kyoto, Japan) was the first commercially available biodegradable scaffold for peripheral use. We evaluated its performance and safety in the treatment of short femoropopliteal stenosis or occlusion.

METHODS

A prospective, multicenter, observational registry was set up of patients in Rutherford-Becker categories 2 to 5 with femoropopliteal lesions that could be treated with one REMEDY stent. Clinical examination and duplex ultrasound imaging were performed at 1, 6, and 12 months. The primary end point was absence of clinically driven target lesion revascularization at 12 months. Secondary end points were technical and clinical success, primary and secondary patency rate, clinically driven target vessel revascularization, major complications, and Rutherford-Becker classification at 6 and 12 months.

RESULTS

The registry enrolled 99 patients between January 2011 and July 2013 in 12 centers in Belgium. Most lesions were determined as TransAtlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) A (n = 80) and located in the superficial femoral artery (n = 91). There were 19 total occlusions (mean length, 41.3 mm) and 80 stenoses (mean length, 37.5 mm). Technical success was achieved in 96 patients, and clinical success was obtained in 95. Target lesion revascularization, which equalled target vessel revascularization, was 19% at 6 months and rose to 33% at 12 months. Primary patency was 68% at 6 months and 58% at 12 months. Secondary patency was 85% at 6 months and 86% at 12 months. After 12 months, two patients had undergone an amputation.

CONCLUSIONS

The 1-year follow-up results of the REMEDY stent do not meet current standards set by nitinol stents. Given the significant issues concerning bioresorbable stents in femoropopliteal arteries, their use outside clinical trials should be withheld until improvements are made and better data are available.