Management of isolated femoropopliteal in-stent restenosis

Surveillance After Surgical and Endovascular Treatment for Peripheral Artery Disease: a Dutch Survey

OBJECTIVE

At present, there is no clear, optimal approach to surveillance after invasive treatment of peripheral artery disease (PAD) in terms of modality, duration, clinical benefit, and cost effectiveness. The ongoing debate on the clinical benefit and cost effectiveness of standard surveillance creates a clear knowledge gap and may result in overtreatment or undertreatment. In this study, a survey was conducted among vascular surgeons in the Netherlands to assess the currently applied surveillance programmes.

METHODS

All vascular surgeons from the Dutch Society for Vascular Surgery received an online survey on follow up after open and endovascular revascularisation in patients with PAD. Surveillance was defined as at least one follow up visit after intervention with or without additional imaging or ankle brachial index (ABI) measurement. Ten types of PAD intervention were surveyed.

RESULTS

Surveys were returned by 97 (46.2%) of 210 vascular surgeons, and 76% reported using a routine follow up protocol after an invasive intervention. Clinical follow up only is most commonly performed after femoral endarterectomy (53%). After peripheral bypass surgery, clinical follow up only is applied rarely (4 - 8%). In six of the 10 interventions surveyed, duplex ultrasound (DUS) was the most used imaging modality for follow up. After bypass surgery, 76 - 86% of vascular surgeons perform DUS with or without ABI measurement. After endovascular interventions, 21 - 60% performed DUS surveillance. Lifelong surveillance is most often applied after aortobifemoral bypass (57%). Surveillance frequency and duration vary greatly within the same intervention. Frequencies range from every three or six months to annually. Duration ranges from one time surveillance to lifelong follow up.

CONCLUSION

There is significant practice variation in surveillance after surgical and endovascular treatment of patients with PAD in the Netherlands. Prospective studies to evaluate treatment outcomes and to define the clinical need and cost effectiveness of standardised surveillance programmes for patients with PAD are recommended.

Perioperative complications of minor and major reinterventions for peripheral arterial disease

INTRODUCTION

Patients with peripheral arterial disease (PAD) frequently require reinterventions after lower-extremity revascularization (LER) to maintain perfusion. Current Society for Vascular Surgery guidelines define reinterventions as major or minor based on the magnitude of the procedure. While prior studies have compared primary LER procedures of different magnitudes, similar studies for reinterventions have not been performed. The objective of this study is to compare perioperative outcomes associated with major and minor reinterventions.

METHODS

Patients undergoing LER for PAD at a tertiary care center from 2013 to 2017 were included. A retrospective review of electronic medical records was performed, and reinterventions were categorized as major or minor based on the procedure magnitude. Minor reinterventions included endovascular procedures and open revision with patch angioplasty, while major reinterventions were characterized by open surgical or endovascular LER with catheter-directed thrombolysis (CDT). Perioperative outcomes following LER were captured and compared for major and minor reinterventions. An additional subgroup analysis was performed comparing outcomes associated with major reinterventions stratified into open major surgical reinterventions and CDT.

RESULTS

This study included 713 patients over a mean follow-up of 2.5 years. A total of 291 patients underwent 696 ipsilateral reinterventions (range = 1-12 reinterventions). Most reinterventions were minor (72.1%, N = 502) and 27.9% (N = 194) were major. Patients receiving reinterventions had an average age of 67.2 ± 11.5 and most were white (73.5%) males (60.1%) initially treated for claudication (58.2%) and CLTI (41.8%). There was significantly higher post-operative bleeding (9.8% vs 3.4%, p = .001), arterial thrombosis (3.1% vs 1.0%, p = .047), and acute renal failure (6.2% vs 2.4%, p = .014) after major reinterventions than minor. Additionally, major reinterventions had significantly higher return to the OR (17.0% vs 11.3%, p = .046) and longer hospital stays (7.5 vs 4.3 days, p = <.0001). Overall, major reinterventions were associated with significantly increased perioperative morbidity (37.6% vs 19.7%, p ≤ .001) with no difference in perioperative mortality. In the subgroup analysis, open reinterventions resulted in significantly longer hospital stays (8.6 days vs 5.5 days, p ≤ .001) and more wound infections than CDT (11.0% vs 0%, p = .017). However, there was no other significant difference in morbidity or mortality following treatment with open surgical reinterventions or CDT.

CONCLUSIONS

In this study, major reinterventions after LER were associated with greater perioperative morbidity than minor reinterventions, with no difference in mortality. Major reinterventions performed via open surgery and CDT had similar morbidity and mortality.

Mechanical, structural, and physiologic differences between above and below-knee human arteries

Peripheral Artery Disease (PAD) affects the lower extremities and frequently results in poor clinical outcomes, especially in the vessels below the knee. Understanding the biomechanical and structural characteristics of these arteries is important for improving treatment efficacy, but mechanical and structural data on tibial vessels remain limited. We compared the superficial femoral (SFA) and popliteal (PA) arteries that comprise the above-knee femoropopliteal (FPA) segment to the infrapopliteal (IPA) anterior tibial (AT), posterior tibial (PT), and fibular (FA) arteries from the same 15 human subjects (average age 52, range 42-67 years, 87 % male). Vessels were imaged using μCT, evaluated with biaxial mechanical testing and constitutive modeling, and assessed for elastin, collagen, smooth muscle cells (SMCs), and glycosaminoglycans (GAGs). IPAs were more often diseased or calcified compared to the FPAs. They were also twice smaller, 53 % thinner, and significantly stiffer than the FPA longitudinally, but not circumferentially. IPAs experienced 48 % higher physiologic longitudinal stresses (62 kPa) but 27 % lower circumferential stresses (24 kPa) and similar cardiac cycle stretch of <1.02 compared to the FPA. IPAs had lower longitudinal pre-stretch (1.12) than the FPAs (1.29), but there were no differences in the stored elastic energy during pulsation. The physiologic circumferential stiffness was similar in the above and below-knee arteries (718 kPa vs 754 kPa). Structurally, IPAs had less elastin, collagen, and GAGs than the FPA, but maintained similar SMC content. Our findings contribute to a better understanding of segment-specific human lower extremity artery biomechanics and may inform the development of better medical devices for PAD treatment. STATEMENT OF SIGNIFICANCE: Peripheral Artery Disease (PAD) in the lower extremity arteries exhibits distinct characteristics and results in different clinical outcomes when treating arteries above and below the knee. However, their mechanical, structural, and physiologic differences are poorly understood. Our study compared above- and below-knee arteries from the same middle-aged human subjects and demonstrated distinct differences in size, structure, and mechanical properties, leading to variations in their physiological behavior. These insights could pave the way for creating location-specific medical devices and treatments for PAD, offering a more effective approach to its management. Our findings provide new, important perspectives for clinicians, researchers, and medical device developers interested in treating PAD in both above- and below-knee locations.

Impact of routine surveillance duplex ultrasound and subsequent reintervention after superficial femoral artery stenting

OBJECTIVE

Superficial femoral artery (SFA) stenting is a common treatment for peripheral artery disease. It is effective in the short term; however, in-stent restenosis (ISR) limits long-term success. Surveillance with duplex ultrasound (DUS) can identify patients who develop ISR leading to early reintervention, but data to support this practice is sparce. The purpose of this study was to evaluate whether surveillance and subsequent reintervention improves outcomes in patients with SFA stents.

METHODS

A single-center, retrospective study was performed with patients undergoing SFA stenting between 2005 and 2020 who had a follow-up with DUS. Five groups were identified based on the presence of ISR on DUS (ISR vs no ISR [NISR]), recurrence of symptoms (symptomatic [SX] vs asymptomatic [ASX]), and if any reintervention was performed (reintervention [R] vs no reintervention [NR]): (1) ISR+SX+R; (2) ISR+SX+NR; (3) ISR+ASX+R; (4) ISR+ASX+NR; and (5) NISR+NR. The primary endpoint was amputation-free survival, and the secondary endpoint was patency. Predictors of mortality and surveillance were identified by multivariable logistic regressions and Cox multivariate regression models. Survival curves were presented as Kaplan-Meier plots using log-rank test for subgroup comparison.

RESULTS

Two hundred fifty-seven patients were included in the analysis. The indication for intervention was claudication in 28% and chronic limb-threatening ischemia in 72%. A total of 161 patients (63%) underwent reintervention for ISR. Of patients who had restenosis on DUS, those who were symptomatic and did not undergo reintervention (ISR+SX+NR) did the worst, with 50% amputation rate. In contrast, those who were asymptomatic but did undergo reintervention (ISR+ASX+R) had the lowest amputation rate of 13%. Active smoking was a predictor of both loss of patency and amputation (1.72; 95% confidence interval [CI], 1.00-2.98; P = .050; 3.55; 95% CI, 1.53-8.25; P = .003). Post procedure dual antiplatelet therapy had a positive association with limb salvage (hazard ratio [HR], 0.23; 95% CI, 0.09-0.58; P = .001), whereas diabetes (HR, 2.61; 95% CI, 1.21-6.01; P = .019), stent occlusion (HR, 17.0; 95% CI, 5.93-63.1; P < .001), and chronic limb-threatening ischemia presentations (HR, 4.31; 95% CI, 1.86-11.7; P=.002) were negatively associated with limb salvage.

CONCLUSIONS

Routine surveillance DUS and subsequent reintervention on ISR after SFA stenting is associated with improved patency and amputation-free survival. Surveillance DUS should be routine for patients after stenting, with reintervention strongly considered if ISR is identified for both symptomatic and asymptomatic.

Superficial Femoral Artery in-Stent Restenosis Treated with Paclitaxel-Coated Balloon Angioplasty - Results of Three-Year Follow-Up

BACKGROUND

In-stent restenosis remains a common and important complication after endovascular treatment of superficial femoral artery peripheral artery disease. It occurs in 14 to 35% of cases in 1 year and there is still no efficient treatment for this condition. Paclitaxel-coated balloons have shown promising results.

OBJECTIVE

Investigate the 3 year results of superficial femoral artery in-stent restenosis treated with paclitaxel-coated balloon angioplasty, using the Lutonix™ 035 device.

METHODS

We conducted a retrospective observational study with patients with symptomatic (Rutherford 2 to 5) superficial femoral artery in-stent restenosis, that were treated with paclitaxel-coated balloon angioplasty using the Lutonix™ 035 device, in a single center from January 2016 to December 2020. Duplex scan was used to follow the patients. Primary patency was obtained through Kaplan-Meier analysis. Mortality, and amputation rates were also evaluated.

RESULTS

105 patients were included. Two patients had technical failure and required an additional stent, and were thus excluded. 103 patients were analyzed. Primary patency was 91.26, 80.47, and 67.71%, respectively, in the first, second, and third year after the procedure. There were no deaths 30 days after the procedure. There were no major amputations during the 3 year follow-up.

CONCLUSION

Paclitaxel-coated balloon angioplasty with the Lutonix™ 035 device was a safe and effective treatment to superficial femoral artery in-stent restenoses. The results were maintained along the 3 year follow-up.

Mulberry extract upregulates cholesterol efflux and inhibits p38 MAPK-NLRP3-mediated inflammation in foam cells

The accumulation of foam cells in arterial intima and the accompanied chronic inflammation are considered major causes of neoatherosclerosis and restenosis. However, both the underlying mechanism and effective treatment for the disease are yet to be uncovered. In this study, we combined transcriptome profiling of restenosis artery tissue and bioinformatic analysis to reveal that NLRP3 inflammasome is markedly upregulated in restenosis and that several restenosis-related DEGs are also targets of mulberry extract, a natural dietary supplement used in traditional Chinese medicine. We demonstrated that mulberry extract suppresses the formation of ox-LDL-induced foam cells, possibly by upregulating the cholesterol efflux genes ABCA1 and ABCG1 to inhibit intracellular lipid accumulation. In addition, mulberry extract dampens NLRP3 inflammasome activation by stressing the MAPK signaling pathway. These findings unveil the therapeutic value of mulberry extract in neoatherosclerosis and restenosis treatment by regulating lipid metabolism and inflammatory response of foam cells.

A method of assessing peripheral stent abrasiveness under cyclic deformations experienced during limb movement

Poor outcomes of peripheral arterial disease stenting are often attributed to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our goals were to develop a method of assessing the abrasiveness of peripheral nitinol stents and apply it to several commercial devices. Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera stents were deployed inside electrospun nanofibrillar tubes with femoropopliteal artery-mimicking mechanical properties and subjected to cyclic axial compression (25%), bending (90°), and torsion (26°/cm) equivalent to five life-years of severe limb flexions. Abrasion was assessed using an abrasion damage score (ADS, range 1-7) for each deformation mode. Misago produced the least abrasion and no stent fractures (ADS 3). Innova caused small abrasion under compression and torsion but large damage under bending (ADS 7). Supera performed well under bending and compression but caused damage under torsion (ADS 8). AbsolutePro produced significant abrasion under bending and compression but less damage under torsion (ADS 12). Zilver fractured under all three deformations and severely abraded the tube under bending and compression (ADS 15). SmartControl and SmartFlex fractured under all three deformations and produced significant abrasion due to strut penetration (ADS 20 and 21). ADS strongly correlated with clinical 12-month primary patency and target lesion revascularization rates, and the described method of assessing peripheral stent abrasiveness can guide device selection and development. STATEMENT OF SIGNIFICANCE: Poor outcomes of peripheral arterial disease stenting are related to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our study presents the first attempt at assessing peripheral stent abrasiveness, and the proposed method is applied to compare the abrasion damage caused by Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera peripheral stents using artery-mimicking synthetic tubes and cyclic deformations equivalent to five life-years of severe limb flexions. The abrasion damage caused by stents strongly correlates with their clinical 12-month primary patency and target lesion revascularization rates, and the described methodology can be used as a cost-effective and controlled way of assessing stent performance, which can guide device selection and development.

Bailout stenting in femoropopliteal arterial segment

Background: Disabling peripheral arterial disease (PAD) of femoropopliteal segment is usually treated with percutaneous balloon dilatation, and when this is not successful, stent is placed. Long-term patency of stent is often compromised due to in-stent restenosis (ISR). We aimed to identify factors associated with bailout stenting, and to recognise risk factors for ISR in procedures without paclitaxel application. Patients and methods: We analysed 592 consecutive successful femoropopliteal interventions performed in patients with either disabling intermittent claudication or chronic critical limb ischemia (CLI). In patients with stent implantation, clinical and ultrasound (US) examination were performed one year after the intervention to establish the presence of ISR, defined as >50% stenosis on US imaging. Results: Bailout stenting was required in 133 (22.5%) procedures. Patients with stent placement were younger (70±10 vs 72±11 years, p=0.007) and less often presented with CLI (29.3% vs 40.5%, p=0.019). They more often reported smoking (63.2% vs 49.2%, p=0.005), less often had diabetes mellitus (35.3% vs 47.5%, p=0.013) and arterial hypertension (82.0% vs 90.8%; p=0.004). Stenting was also dependent on lesion complexity (TASC II C>B>A; p<0.001). Subgroup analysis of 110 procedures with bare metal stent (BMS) placement performed in 107 patients revealed ISR in 46.4% of stents, in half of cases it was symptomatic. Neither clinical nor lesion characteristics proved to differ between the group of procedures with ISR and group of procedures without ISR. Conclusions: Factors associated with bailout stenting were age, diabetes mellitus, arterial hypertension, smoking, clinical picture of PAD and complexity of treated lesions. We did not find any risk factors influencing development of ISR in BMS.

Comparison of morphometric, structural, mechanical, and physiologic characteristics of human superficial femoral and popliteal arteries

Peripheral arterial disease differentially affects the superficial femoral (SFA) and the popliteal (PA) arteries, but their morphometric, structural, mechanical, and physiologic differences are poorly understood. SFAs and PAs from 125 human subjects (age 13-92, average 52±17 years) were compared in terms of radii, wall thickness, and opening angles. Structure and vascular disease were quantified using histology, mechanical properties were determined with planar biaxial extension, and constitutive modeling was used to calculate the physiologic stress-stretch state, elastic energy, and the circumferential physiologic stiffness. SFAs had larger radii than PAs, and both segments widened with age. Young SFAs were 5% thicker, but in old subjects the PAs were thicker. Circumferential (SFA: 96→193°, PA: 105→139°) and longitudinal (SFA: 139→306°, PA: 133→320°) opening angles increased with age in both segments. PAs were more diseased than SFAs and had 11% thicker intima. With age, intimal thickness increased 8.5-fold, but medial thickness remained unchanged (620μm) in both arteries. SFAs had 30% more elastin than the PAs, and its density decreased ~50% with age. SFAs were more compliant than PAs circumferentially, but there was no difference longitudinally. Physiologic circumferential stress and stiffness were 21% and 11% higher in the SFA than in the PA across all ages. The stored elastic energy decreased with age (SFA: 1.4→0.4kPa, PA: 2.5→0.3kPa). While the SFA and PA demonstrate appreciable differences, most of them are due to vascular disease. When pathology is the same, so are the mechanical properties, but not the physiologic characteristics that remain distinct due to geometrical differences.

Enhancing biocompatibility and corrosion resistance of biodegradable Mg-Zn-Y-Nd alloy by preparing PDA/HA coating for potential application of cardiovascular biomaterials

In this paper the poly-dopamine (PDA)/hyaluronic acid (HA) coatings with different HA molecular weight (MW, 4 × 10³, 1 × 10⁵, 5 × 10⁵ and 1 × 10⁶ Da) were prepared onto the NaOH passivated Mg-Zn-Y-Nd alloy aiming at potential application of cardiovascular implants. The characterization of weight loss, polarization curves and surface morphology indicated that the coatings with HA MW of 1 × 10⁵ (PDA/HA-2) and 1 × 10⁶ Da (PDA/HA-4) significantly enhanced the corrosion resistance of Mg-Zn-Y-Nd. In vitro biological test also suggested better hemocompatibility, pro-endothelialization, anti-hyperplasia and anti-inflammation functions of the PDA/HA-2- and PDA/HA-4-coated Mg-Zn-Y-Nd alloy. Nevertheless, the in vivo implantation of SD rats' celiac artery demonstrated that the PDA/HA-2 had preferable corrosion resistance and biocompatibility.

Mechanical damage characterization in human femoropopliteal arteries of different ages

Endovascular treatment of Peripheral Arterial Disease (PAD) is notorious for high failure rates, and interaction between the arterial wall and the repair devices plays a significant role. Computational modeling can help improve clinical outcomes of these interventions, but it requires accurate inputs of elastic and damage characteristics of the femoropopliteal artery (FPA) which are currently not available. Fresh human FPAs from n = 104 tissue donors 14-80 years old were tested using planar biaxial extension to capture elastic and damage characteristics. Damage initiation stretches and stresses were determined for both longitudinal and circumferential directions, and their correlations with age and risk factors were assessed. Two and four-fiber-family invariant-based constitutive models augmented with damage functions were used to describe stress softening with accumulating damage. In FPAs younger than 50 years, damage began accumulating after 1.51 ± 0.13 and 1.49 ± 0.11 stretch, or 196 ± 110 kPa and 239 ± 79 kPa Cauchy stress in the longitudinal and circumferential directions, respectively. In FPAs older than 50 years, damage initiation stretches and stresses decreased to 1.27 ± 0.09 (106 ± 52 kPa) and 1.26 ± 0.09 (104 ± 59 kPa), respectively. Damage manifested primarily as tears at the internal and external elastic laminae and within the tunica media layer. Higher body mass index and presence of diabetes were associated with lower damage initiation stretches and higher stresses. The selected constitutive models were able to accurately portray the FPA behavior in both elastic and inelastic domains, and properties were derived for six age groups. Presented data can help improve fidelity of computational models simulating endovascular PAD repairs that involve arterial damage. STATEMENT OF SIGNIFICANCE: This manuscript describes inelastic, i.e. damage, behavior of human femoropopliteal arteries, and provides values for three constitutive models simulating this behavior computationally. Using a set of 104 human FPAs 14-80 years old, we have investigated stress and stretch levels corresponding to damage initiation, and have studied how these damage characteristics change across different age groups. Presented inelastic arterial characteristics are important for computational simulations modeling balloon angioplasty and stenting of peripheral arterial disease lesions.

Noninvasive Arterial Testing: What and When to Use

Peripheral arterial disease (PAD) represents a growing public health issue that continues to be underdiagnosed. In its most severe form, critical limb ischemia, it contributes to expanding morbidity with minor and major limb amputations. PAD is strongly associated with increased mortality, as it is known to be concomitant with coronary and cerebrovascular disease. Diagnosis of PAD relies on noninvasive arterial testing, a class of tests that can provide physiologic or morphologic information. Physiologic tests such as ankle-brachial index, toe-brachial index, pulse volume recordings, and arterial duplex evaluation are the mainstay of gateway evaluation and surveillance. Morphologic exams such as computer tomographic angiography and magnetic resonance angiography are appropriate for preprocedural anatomic evaluation in patients with established vascular disease. This review focuses on physiologic exams.