Patterns and mechanisms of in-stent restenosis. A serial intravascular ultrasound study

Endovascular treatment of re-stenotic iliac artery stents with drug-eluting balloons

AIM

To evaluate the results of revascularization of stenotic iliac stents using drug-eluting balloons (DEBs).

MATERIAL AND METHODS

Seventy-four patients with various levels of iliac stent restenosis were enrolled to study. All restenotic stents were treated using paclitaxel-coated balloons.

RESULTS

Through a follow-up median period of 24 months (4-24 months), there were no in-stent re-restenosis in 55 patients (74.3%) and there was one in class 1 (1.4%), four in class 2 (5.4%), and fourteen in class 3 (18.9%).

CONCLUSION

We conclude that; DEBs can be used for restenotic iliac artery stents for some Type C and D lesions, in addition to Types A and B with satisfacting results.

Silencing of PCK1 mitigates the proliferation and migration of vascular smooth muscle cells and vascular intimal hyperplasia by suppressing STAT3/DRP1-mediated mitochondrial fission

The pathological proliferation and migration of vascular smooth muscle cells (VSMCs) are key processes during vascular neointimal hyperplasia (NIH) and restenosis. Phosphoenolpyruvate carboxy kinase 1 (PCK1) is closely related to a variety of malignant proliferative diseases. However, the role of PCK1 in VSMCs has rarely been investigated. This study aims to examine the role of PCK1 in the proliferation and migration of VSMCs and vascular NIH after injury. In vivo, extensive NIH and increased expression of PCK1 within the neointima are observed in injured arteries. Interestingly, the administration of adeno-associated virus-9 (AAV-9) carrying Pck1 short hairpin RNA (sh Pck1) significantly attenuates NIH and stenosis of the vascular lumen. In vitro, Pck1 small interfering RNA (si Pck1)-induced PCK1 silencing inhibits VSMC proliferation and migration. Additionally, silencing of PCK1 leads to reduced expression of dynamin-related protein 1 (DRP1) and attenuated mitochondrial fission. Lentivirus-mediated DRP1 overexpression markedly reverses the inhibitory effects of PCK1 silencing on VSMC proliferation, migration, and mitochondrial fission. Finally, PCK1 inhibition attenuates the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Activation of STAT3 abolishes the suppressive effects of PCK1 silencing on DRP1 expression, mitochondrial fission, proliferation, and migration in VSMCs. In conclusion, PCK1 inhibition attenuates the mitochondrial fission, proliferation, and migration of VSMCs by inhibiting the STAT3/DRP1 axis, thereby suppressing vascular NIH and restenosis.

Emerging Hybrid Intracoronary Imaging Technologies and Their Applications in Clinical Practice and Research

Intravascular ultrasound and optical coherence tomography are used with increasing frequency for the care of coronary patients and in research studies. These imaging tools can identify culprit lesions in acute coronary syndromes, assess coronary stenosis severity, guide percutaneous coronary intervention (PCI), and detect vulnerable plaques and patients. However, they have significant limitations that have stimulated the development of multimodality intracoronary imaging catheters, which provide improvements in assessing vessel wall pathology and guiding PCI. Prototypes combining 2 or even 3 imaging probes with complementary attributes have been developed, and several multimodality systems have already been used in patients, with near-infrared spectroscopy intravascular ultrasound-based studies showing promising results for the identification of high-risk plaques. Moreover, postmortem histology studies have documented that hybrid imaging catheters can enable more accurate characterization of plaque morphology than standalone imaging. This review describes the evolution in the field of hybrid intracoronary imaging; presents the available multimodality catheters; and discusses their potential role in PCI guidance, vulnerable plaque detection, and the assessment of endovascular devices and emerging pharmacotherapies targeting atherosclerosis.

Lipoprotein(a) and Long-term In-stent Restenosis after Percutaneous Coronary Intervention

AIM

Lipoprotein(a) [Lp(a)] has demonstrated its association with atherosclerosis and myocardial infarction. However, its role in the development of in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) is not clearly established. The aim of this study is to investigate the association between Lp(a) and ISR.

METHODS

A retrospective study of adult patients who underwent successful PCI between January 2006 and December 2017 at the three Mayo Clinic sites and had a preprocedural Lp(a) measurement was conducted. Patients were divided into two groups according to the serum Lp(a) concentration (high Lp(a) ≥50 mg/dl and low Lp(a) <50 mg/dl). Univariable and multivariable analyses were performed to compare risk of ISR between patients with high Lp(a) versus those with low Lp(a).

RESULTS

A total of 1209 patients were included, with mean age 65.9 ±11.7 years and 71.8% were male. Median follow-up after baseline PCI was 8.8 (IQR 7.4) years. Restenosis was observed in 162 (13.4%) patients. Median serum levels of Lp(a) were significantly higher in patients affected by ISR versus non-affected cases: 27 (IQR 73.8) vs. 20 (IQR 57.5) mg/dL, p=0.008. The rate of ISR was significantly higher among patients with high Lp(a) versus patients with low Lp(a) values (17.0% vs 11.6%, p=0.010). High Lp(a) values were independently associated with ISR events (HR 1.67, 95%CI 1.18 to 2.37, p=0.004), and this association was more prominent after the first year following the PCI.

CONCLUSION

Lipoprotein(a) is an independent predictor for long-term in-stent restenosis and should be considered in the evaluation of patients undergoing PCI.

Genetically encoded biocompatible anti-coagulant protein-coated coronary artery stents drive endothelialization

In response to the critical demand for advancements in coronary artery stents, this study addresses the challenges associated with arterial recoil and restenosis post-angioplasty and the imperative to encourage rapid re-endothelialization for minimizing thrombosis risks. We employed an innovative approach inspired by mussel adhesion, incorporating placental anticoagulant protein (AnnexinV) on stent design. The introduction of a post-translationally modified catecholic amino acid L-3,4-dihydroxyphenylalanine (L-Dopa), mimicking mussel characteristics, allowed for effective surface modification of Stainless steel stents through genetic code engineering in AnnexinV (AnxDopa). The efficacy of AnxDopa was analyzed through microscale thermophoresis and flow cytometry, confirming AnxDopa's exceptional binding with phosphatidylserine and activated platelets. AnxDopa coated stainless steel demonstrates remarkable bio-, hemo-, and immuno-compatibility, preventing smooth muscle cell proliferation, platelet adhesion, and fibrin formation. It acts as an interface between the stent and biological fluid, which facilitates the anticoagulation and rapid endothelialization. Surface modification of SS verified through XPS analysis and contact angle measurement attests to the efficacy of AnxDopa mediated surface modification. The hydrophilic nature of the AnxDopa-coated surface enhanced the endothelialization through increased protein absorption. This approach represents a significant stride in developing coronary stents with improved biocompatibility and reduced restenosis risks, offering valuable contributions to scientific and clinical realms alike.

Successful healing of aneurysmal false lumen using a second-generation drug-eluting stent in spontaneous coronary artery dissection: a case report

BACKGROUND

According to 2023 ESC Guideline, conservative medical management is generally recommended for the treatment of spontaneous coronary artery dissection (SCAD) except for patients with signs of ongoing myocardial ischemia. However, in some cases, invasive treatment (coronary artery bypass graft surgery or percutaneous coronary intervention (PCI)) is performed because of the progression of aneurysm in SCAD. Although there is no established strategy for the management of coronary aneurysm in SCAD, we report a case of successful healing of aneurysmal false lumen (AFL) using a second-generation drug-eluting stent (DES) in SCAD.

CASE PRESENTATION

A 44-year-old woman without any cardiovascular risk factors was transferred to our hospital due to inferior myocardial infarction. Coronary angiography (CAG) showed multiple SCADs in the coronary artery. We performed PCI to the distal right coronary artery (RCA) because the RCA showed severe stenosis (99%) with bradycardia. Six days after the first PCI, SCAD relapsed in the mid left anterior descending artery (LAD). Furthermore, AFL was observed by intravascular ultrasound imaging. To avoid enlargement of the AFL and progression of the dissection toward the proximal site of the LAD, we performed PCI to the mid LAD to seal the entry tear of the dissection using a second-generation DES. CAG revealed that the AFL in the mid LAD completely diminished at 1 year after PCI.

CONCLUSIONS

The implantation of a second-generation DES might be one of therapeutic options for sealing AFL in SCAD patients.

Cephalic arch stenosis: an analysis of outcome by type of first intervention

BACKGROUND

Cephalic arch stenoses (CAS) occur in near 70% of elbow arteriovenous fistulas. Percutaneous transluminal angioplasty (PTA) remains first-line treatment despite documented stent-grafts (SG) efficacy. The study aim is to report long-term outcomes based on initial treatment of CAS.

METHODS

Retrospective review of 12-year data in single tertiary centre. Outcomes included technical success, rupture rate, primary patency (PP), dialysis performance; categorical variables assessed via χ2 or Fisher's; nonparametric tests used for skewed data. Kaplan-Meier analysis used for PP and cumulative patency. Cox proportional hazard regression model to assess explanatory variables in PP.

RESULTS

One hundred one brachio- and radiocephalic fistulas with CAS were included. SG as first intervention had higher success than PTA (85% vs 61%, p = 0.003). Rupture occurred in 9/85 (10.6%) PTA vs 0% in SG (p = 0.046). In a subgroup with poor urea reduction rate (URR), both PTA and SG improved dialysis performance post-intervention (p = 0.002). SG demonstrated better PP than PTA (79,73,60% patency at 3, 6, 9 months; versus 71,51,47%; p = 0.195) and cumulative patency (73,61,61% at 1, 2, 3 years; versus 60,34,26%; p < 0.001). Of the variables analyzed, technical success of PTA was the only discriminating factor (coeff.-1.01; RR 35%, p = 0.035). Accesses that underwent secondary stenting performed better than primarily stented CAS (p = 0.01).

CONCLUSIONS

SG superiority is confirmed in CAS, particularly when angioplasty is unsuccessful. While PTA has short-lived benefits, it can improve dialysis performance. Other than higher success rate, primary CAS stenting did not have advantages compared to post-PTA stenting in our study. Other factors related to inflow, outflow, conduit characteristics are presumed to be involved in access longevity.

Comparison of Clinical Outcomes Among Various Percutaneous Coronary Intervention Strategies for Small Coronary Artery Disease

It remains unclear which percutaneous coronary intervention (PCI) strategy is the most preferable in patients with small-vessel coronary artery disease (CAD). We sought to evaluate the clinical efficacy of various PCI strategies for patients with small-vessel CAD through a network meta-analysis of randomized controlled trials (RCTs). We searched multiple databases for RCTs investigating the efficacy of the following PCI strategies for small-vessel CAD (<3 mm in diameter): drug-coated balloons (DCB), early-generation paclitaxel-eluting stents and sirolimus-eluting stents (SES), newer-generation drug-eluting stents (DES), bare-metal stents (BMS), cutting balloon angioplasty, and balloon angioplasty (BA). The primary outcome was the trial-defined major adverse cardiovascular events (MACE), mostly defined as a composite of death, myocardial infarction, and revascularization. The secondary outcomes included each component of MACE and angiographic binary restenosis. We performed a sensitivity analysis for RCTs without BMS or first-generation DES. Our search identified 29 eligible RCTs, including 8,074 patients among the 8 PCI strategies. SES significantly reduced MACE compared with BA (hazard ratio 0.23, 95% confidence interval 0.10 to 0.54) with significant heterogeneity (I2 = 55.9%), and the rankogram analysis showed that SES was the best. There were no significant differences between DCB and newer-generation DES in any clinical outcomes, which was consistent in the sensitivity analysis. BMS and BA were ranked as the worst 2 for most clinical outcomes. In conclusion, SES was ranked as the best for reducing MACE. There were no significant differences in clinical outcomes between DCB and newer-generation DES. BMS and BA were regarded as the worst strategies for small-vessel CAD.

Gallic Acid Inhibits Proliferation and Migration of Smooth Muscle Cells in a Pig In-Stent Restenosis Model

In-stent restenosis (ISR) develops primarily due to neointimal hyperplasia. Gallic acid (GA) has anti-inflammatory, antioxidant, and cardioprotective effects. This study sought to investigate the effects of GA on neointimal hyperplasia and proliferation and migration of vascular smooth muscle cells (VSMCs) in a pig ISR model. In vitro proliferation and migration experiments were confirmed, after VSMCs were treated with platelet-derived growth factor (PDGF-BB) and GA (100 µM) using a 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT) assay and a scratch wound assay for 24 hours and 48 hours. A bare metal stent (BMS) was implanted in the pig coronary artery to induce ISR with overdilation (1.1-1.2:1), and GA (10 mg/kg/day) was administered for 4 weeks. At the 4-week follow-up, optical coherence tomography (OCT) and histopathological analyses were performed. GA decreased the proliferation of VSMCs by PDGF-BB for 24 hours (89.24±24.56% vs. 170.04±19.98%, p<0.001) and 48 hours (124.87±7.35% vs. 187.64±4.83%, p<0.001). GA inhibited the migration of VSMCs induced by PDGF-BB for 24 hours (26.73±2.38% vs. 65.38±9.73%, p<0.001) and 48 hours (32.96±3.04% vs. 77.04±10.07%, p<0.001). Using OCT, % neointimal hyperplasia was shown to have significantly decreased in the GA group compared with control vehicle group (28.25±10.07% vs. 37.60±10.84%, p<0.001). GA effectively reduced neointimal hyperplasia by inhibiting the proliferation and migration of VSMCs in a pig ISR model. GA could be a potential treatment strategy for reducing ISR after stent implantation.

Development and Future Trends of Protective Strategies for Magnesium Alloy Vascular Stents

Magnesium alloy stents have been extensively studied in the field of biodegradable metal stents due to their exceptional biocompatibility, biodegradability and excellent biomechanical properties. Nevertheless, the specific in vivo service environment causes magnesium alloy stents to degrade rapidly and fail to provide sufficient support for a certain time. Compared to previous reviews, this paper focuses on presenting an overview of the development history, the key issues, mechanistic analysis, traditional protection strategies and new directions and protection strategies for magnesium alloy stents. Alloying, optimizing stent design and preparing coatings have improved the corrosion resistance of magnesium alloy stents. Based on the corrosion mechanism of magnesium alloy stents, as well as their deformation during use and environmental characteristics, we present some novel strategies aimed at reducing the degradation rate of magnesium alloys and enhancing the comprehensive performance of magnesium alloy stents. These strategies include adapting coatings for the deformation of the stents, preparing rapid endothelialization coatings to enhance the service environment of the stents, and constructing coatings with self-healing functions. It is hoped that this review can help readers understand the development of magnesium alloy cardiovascular stents and solve the problems related to magnesium alloy stents in clinical applications at the early implantation stage.

Efficacy of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitor Treatment for Repeated In-stent Restenosis in a Coronary Artery

A 57-year-old woman experienced chest pain. A coronary angiogram revealed middle left anterior descending artery stenosis. Despite receiving adequate anti-hyperlipidemia treatment and undergoing percutaneous coronary intervention (PCI), she experienced angina and required PCI six more times for in-stent restenosis. As she had high lipoprotein (a) [LP-(a)] levels at the seventh PCI procedure, proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) was administered, and a reduction in the LP-(a) and low-density lipoprotein cholesterol (LDL-C) values was observed. She experienced no recurrence of angina for five years with PCSK9i treatment. PCSK9i can reduce not only LDL-C but also LP-(a) levels, resulting in cardiac event risk reduction.

Advances in Fabrication Technologies for the Development of Next-Generation Cardiovascular Stents

Coronary artery disease is the most prevalent cardiovascular disease, claiming millions of lives annually around the world. The current treatment includes surgically inserting a tubular construct, called a stent, inside arteries to restore blood flow. However, due to lack of patient-specific design, the commercial products cannot be used with different vessel anatomies. In this review, we have summarized the drawbacks in existing commercial metal stents which face problems of restenosis and inflammatory responses, owing to the development of neointimal hyperplasia. Further, we have highlighted the fabrication of stents using biodegradable polymers, which can circumvent most of the existing limitations. In this regard, we elaborated on the utilization of new fabrication methodologies based on additive manufacturing such as three-dimensional printing to design patient-specific stents. Finally, we have discussed the functionalization of these stent surfaces with suitable bioactive molecules which can prove to enhance their properties in preventing thrombosis and better healing of injured blood vessel lining.

Renovisceral artery alterations due to branched endovascular aortic repair and respiratory-induced deformations

OBJECTIVE

This study quantified respiratory-induced dynamics of branch vessels before and after thoracoabdominal aortic aneurysm (TAAA) branched endovascular aneurysm repair (bEVAR).

METHODS

Patients with TAAA were recruited prospectively and treated with bEVAR, predominantly with Zenith t-Branch and BeGraft Peripheral PLUS bridging stents. Using SimVascular software, three-dimensional geometric models of the vessels and implants were constructed from computed tomography angiograms during both inspiratory and expiratory breath-holds, preoperatively and postoperatively. From these models, branch take-off angles, end-stent angles (transition from distal end of stent to native artery), and curvatures were computed. Paired, two-tailed t tests were performed to compare inspiratory vs expiratory geometry and pre- vs postoperative deformations.

RESULTS

We evaluated 52 (12 celiac arteries [CA], 15 superior mesenteric arteries [SMA], and 25 renal arteries [RA]) branched renovisceral vessels with bridging stents in 15 patients. Implantation of bridging stents caused branch take-off angle to shift inferiorly in the SMA (P = .015) and RA (P = .014) and decreased the respiratory-induced branch angle motion in the CA and SMA by approximately 50%. End-stent angle increased from before to after bEVAR for the CA (P = .005), SMA (P = .020), and RA (P < .001); however, respiratory-induced deformation was unchanged. Bridging stents did not experience significant bending owing to respiration.

CONCLUSIONS

The decrease in respiratory-induced deformation of branch take-off angle from before to after bEVAR should decrease the risk of device disengagement and endoleak. The unchanging respiratory-induced end-stent bending, from before to after bEVAR, means that bEVAR maintains native vessel dynamics distal to the bridging stents. This factor minimizes the risk of tissue irritation owing to respiratory cycles, boding well for branch vessel patency. The longer bridging stent paths associated with bEVAR may enable smoother paths subject to less dynamic bending, and potentially lower fatigue risk, compared with fenestrated EVAR.

State-of-art review: intravascular imaging in percutaneous coronary interventions

The history of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) reflects the relentless pursuit of innovation in interventional cardiology. These intravascular imaging technologies have played a pivotal role in our understanding of coronary atherosclerosis, vascular pathology, and the interaction of coronary stents with the vessel wall. Two decades of clinical investigations demonstrating the clinical efficacy and safety of intravascular imaging modalities have established these technologies as staples in the contemporary cardiac catheterization lab's toolbox and earning their place in revascularization clinical practice guidelines. In this comprehensive review, we will delve into the historical evolution, mechanisms, and technical aspects of IVUS and OCT. We will discuss the expanding evidence supporting their use in complex percutaneous coronary interventions, emphasizing their crucial roles in optimizing patient outcomes and ensuring procedural success. Furthermore, we will explore the substantial advances that have propelled these imaging modalities to the forefront of contemporary interventional cardiology. Finally, we will survey the latest developments in the field and explore the promising future directions that have the potential to further revolutionize coronary interventions.

Application of the Willis Covered Stent in the Treatment of Complex Vascular Diseases of the Internal Carotid Artery and Vertebral Artery: A Retrospective Single-Center Experience

Objective

To retrospectively evaluate the efficacy and security of Willis covered stent (WCS) deployment for complex vascular diseases of the internal carotid (ICA) and vertebral (VA) arteries.

Methods

Retrospective analysis was performed on complex vascular disease patients (n=36) treated with WCSs at our center between March 2017 and December 2022, with a 3-36-months follow-up surveillance and digital subtraction angiography (DSA) examination.

Results

The WCSs were successfully deployed in all the patients. The 36 included lesions were carotid-cavernous sinus fistulas (CCFs; n=10) (27.8%), complex saccular aneurysms (n=10) (27.8%), traumatic pseudoaneurysms (n=7) (19.4%), blood blister-like aneurysms (BBAs; n=5) (13.9%), and iatrogenic carotid or vertebral artery ruptures (n=4) (11.1%). The WCS was released at the communicating segment (n=2) (5.6%), the ophthalmic segment (n=3) (8.3%), the clinoid and cavernous segment (n=28) (77.8%), the petrous segment (n=2) (5.6%) of ICA and the V3 segment (n=1) (2.8%) of VA. Postoperative DSA showed complete lesion occlusion in 26 patients (72.2%) who were immediately treated with WCSs, and endoleaks occurred in 3 patients (8.3%) (endoleaks resolved postadjustment in 7 patients (19.4%)). In patients (n=3) (8.3%) treated with double stents at the break of the ICA, the endoleak remained in 1 CCF patient (2.8%) during the 3-month follow-up, and the residual shunt disappeared after the second stent system was placed 3 months later. No aneurysm, bleeding or infarct recurrence reported, and only 1 patient (2.8%) had mild asymptomatic in-stent stenosis. Deaths and procedural complications did not occur during follow-up.

Conclusion

Treatment with a WCS for intracranial complex vascular diseases resulted in satisfactory clinical outcomes and appeared effective and safe. Controlled, multicenter, large sample sizes and longer follow-up periods studies are necessary.

Colchicine efficacy comparison at varying time points in the peri-operative period for coronary artery disease: a systematic review and meta-analysis of randomized controlled trials

Objectives

Over the years, it has been found that colchicine offers substantial benefits in secondary prevention in patients with coronary artery disease (CAD). We studied the effects of colchicine timing because there are no guidelines about when to provide it during the perioperative period for patients with CAD.

Methods

Up to January 1, 2023, seven electronic literature databases were screened (including three English databases and four Chinese databases). Randomized controlled trials included only treatment with colchicine in the perioperative period of CAD. The Cochrane Evaluation Tool was used to judge the risk of bias in research. Statistical analysis was performed by Stata 16.0 software.

Results

We evaluated twelve studies that found colchicine to be effective in decreasing the occurrence of major adverse cardiac events (MACEs) (p < 0.00001), but it also raised the rate of adverse events (p = 0.001). Subgroup analysis showed the same benefit in lowering the incidence of MACE with continuous administration of a total daily dose of 0.5 mg postoperatively while minimizing drug-related side effects in the patients (p = 0.03). When it comes to preventing surgical stroke occurrences, postoperative administration is more effective (p = 0.006). While the effect of simultaneous preoperative and postoperative administration was marginally greater than other periods in reducing postoperative hs-CRP levels (p = 0.02).

Conclusion

Colchicine, a traditional anti-inflammatory drug, also reduces the risk of MACE by reducing inflammation after PCI. Administration at different periods had no significant effect on decreasing the occurrence of MACE, but when administered postoperatively, we advise continuous administration with a total daily dose of 0.5 mg to obtain the same benefit while minimizing the drug's side effects. Postoperative administration is the better measure to prevent postoperative stroke events. Due to the effective anti-inflammatory effect of colchicine, we recommend its use as early as possible in the perioperative period and its continued use at low doses in the postoperative period.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=316751, identifier CRD42022316751.

Angioscopic and histopathological findings of in-stent restenosis in external iliac artery

Little has been reported on the angioscopic and histopathological findings of in-stent restenosis (ISR) in the iliac artery. Here, we report a case of a male patient in his 70s who showed recurrent ISR in the right external iliac artery. We observed the ISR lesions with not only an intravascular ultrasound (IVUS) but also an angioscopy and a biopsy to clarify the mechanism of ISR. These imaging and histopathological findings showed neointimal hyperplasia, and we performed endovascular therapy with covered stent placement to prevent neointimal formation. Not only the IVUS but also the angioscopic and histopathological findings were helpful to clarify the mechanism of ISR and to determine the treatment plan.

Stent failure: the diagnosis and management of intracoronary stent restenosis

INTRODUCTION

Despite advances in stent technology for percutaneous coronary intervention (PCI) in the treatment of coronary disease, these procedures can be complicated by stent failure manifesting as intracoronary stent restenosis (ISR). Even with advances of stent technology and medical therapy this complication is reported to affect around 10% of all percutaneous coronary intervention (PCI) procedures. Depending on stent type (drug-eluting versus bare metal), ISR have subtle differences in mechanism and timing and offer different challenges in diagnosing the etiology and subsequent treatment options.

AREAS COVERED

This review will be visiting the definition, pathophysiology and risk factors of ISR.

EXPERT OPINION

The evidence behind management options has been illustrated with the aid of real life clinical cases and summarized in a proposed management algorithm.

Evaluation of coronary stents: A review of types, materials, processing techniques, design, and problems

In the world, one of the leading causes of death is coronary artery disease (CAD). There are several ways to treat this disease, and stenting is currently the most appropriate way in many cases. Nowadays, the use of stents has rapidly increased, and they have been introduced in various models, with different geometries and materials. To select the most appropriate stent required, it is necessary to have an analysis of the mechanical behavior of various types of stents. The purpose of this article is to provide a complete overview of advanced research in the field of stents and to discuss and conclude important studies on different topics in the field of stents. In this review, we introduce the types of coronary stents, materials, stent processing technique, stent design, classification of stents based on the mechanism of expansion, and problems and complications of stents. In this article, by reviewing the biomechanical studies conducted in this field and collecting and classifying their results, a useful set of information has been presented to continue research in the direction of designing and manufacturing more efficient stents, although the clinical-engineering field still needs to continue research to optimize the design and construction. The optimum design of stents in the future is possible by simulation and using numerical methods and adequate knowledge of stent and artery biomechanics.

Coronary Stenting: Reflections on a 35-Year Journey

Stenting was introduced as a therapy for coronary artery disease 35 years ago, and is currently the most commonly performed minimally invasive procedure globally. Percutaneous coronary revascularization, initially with plain old balloon angioplasty and later with stenting, has dramatically affected the outcomes of acute myocardial infarction and acute coronary syndromes. Coronary stenting is probably the most intensively studied therapy in medicine on the basis of the number of randomized clinical trials for a broad range of indications. Continuous improvements in stent materials, design, and coatings concurrent with procedural innovations have truly been awe-inspiring. The story of stenting is replete with high points and some low points, such as the initial experience with stent thrombosis and restenosis, and the more recent disappointment with bioabsorbable scaffolds. History has shown rapid growth of stent use with expansion of indications followed by contraction of some uses in response to clinical trial evidence in support of bypass surgery or medical therapy. In this review we trace the constantly evolving story of the coronary stent from the earliest experience until the present time. Undoubtedly, future iterations of stent design and materials will continue to move the stent story forward.

The Ongoing Saga of the Evolution of Percutaneous Coronary Intervention: From Balloon Angioplasty to Recent Innovations to Future Prospects

The advances in percutaneous coronary intervention (PCI) have been, above all, dependent on the work of pioneers in surgery, radiology, and interventional cardiology. From Grüntzig's first balloon angioplasty, PCI has expanded through technology development, improved protocols, and dissemination of best-practice techniques. We can nowadays treat more complex lesions in higher-risk patients with favourable results. Guide wires, balloon types and profiles, debulking techniques such as atherectomy or lithotripsy, stents, and scaffolds all represent evolutions that have allowed us to tackle complex lesions such as an unprotected left main coronary artery, complex bifurcations, or chronic total occlusions. Best-practice PCI, including physiology assessment, imaging, and optimal lesion preparation are now the gold standard when performing PCI for sound indications, and new technologies such as intravascular lithotripsy for lesion preparation, or artificial intelligence, are innovations in the steps of 4 decades of pioneers to improve patient care in interventional cardiology. In the present review, major innovations in PCI since the first balloon angioplasty and also uncertainties and obstacles inherent to such medical advances are described.

Hypersensitivity and in-stent restenosis in coronary stent materials

Coronary heart disease (CHD) is a type of cardiovascular disease with the highest mortality rate worldwide. Percutaneous transluminal coronary intervention (PCI) is the most effective method for treating CHD. However, in-stent restenosis (ISR), a long-term complication after PCI, affects the prognosis of patients with CHD. Previous studies have suggested that hypersensitivity reactions induced by metallic components may be one of the reasons of this complication. With the emergence of first- and second-generation drug-eluting stents (DES), the efficacy and prognosis of patients with CHD have greatly improved, and the incidence of ISR has gradually decreased to less than 10%. Nevertheless, DES components have been reported to induce hypersensitivity reactions, either individually or synergistically, and cause local inflammation and neointima formation, leading to long-term adverse cardiovascular events. In this article, we described the relationship between ISR and hypersensitivity from different perspectives, including its possible pathogenesis, and discussed their potential influencing factors and clinical significance.

Coronary In-Stent Restenosis: JACC State-of-the-Art Review

The introduction and subsequent iterations of drug-eluting stent technologies have substantially improved the efficacy and safety of percutaneous coronary interventions. However, the incidence of in-stent restenosis (ISR) and the resultant need for repeated revascularization still occur at a rate of 1%-2% per year. Given that millions of drug-eluting stents are implanted each year around the globe, ISR can be considered as a pathologic entity of public health significance. The mechanisms of ISR are multifactorial. Since the first description of the angiographic patterns of ISR, the advent of intracoronary imaging has further elucidated the mechanisms and patterns of ISR. The armamentarium and treatment strategies of ISR have also evolved over time. Currently, an individualized approach using intracoronary imaging to characterize the underlying substrate of ISR is recommended. In this paper, we comprehensively reviewed the incidence, mechanisms, and imaging characterization of ISR and propose a contemporary treatment algorithm.

Successful implantation of a novel polymer-free everolimus-eluting stent using nitrogen-doped titanium dioxide film with good patency on follow-up angiography: A case report

RATIONALE

Despite technological advances in interventional cardiology during the last decades, many concerns remain regarding the narrowing and occlusion of the in-stent area. Particularly, polymer materials pose several problems, including chronic arterial inflammation, impaired arterial healing, and stent thrombosis. To avoid these complications, we invented the TIGEREVOLUTION stent with a cobalt-chromium alloy-based stent platform deposited with N-TiO2 film, which has demonstrated good biocompatibility. As this stent is not coated with polymer, it is expected to have decreased risk of stent thrombosis.

PATIENT CONCERNS

A 62-year-old Korean man visited our department because of angina. We commenced coronary angiography (CAG).

DIAGNOSIS

CAG revealed critical stenosis in the mid-portion of the right coronary artery, with a minimum lumen area of 1.08mm2 on optical coherence tomography (OCT).

INTERVENTION

Percutaneous coronary intervention was performed with implantation of a novel 3.5 × 26-mm polymer-free everolimus-eluting stent using nitrogen-doped titanium dioxide film (TIGEREVOLUTION® stent). Post-percutaneous coronary intervention OCT showed good stent expansion and apposition, and the patient was discharged successfully and uneventfully.

OUTCOMES

Eight months later, follow-up coronary angiography demonstrated good stent patency with no definitive evidence of in-stent restenosis, with thin stent strut coverage demonstrated on OCT.

LESSONS

We report the first case of TIGEREVOLUTION stent implantation with follow-up OCT at 8 months.

Directional versus orbital atherectomy of femoropopliteal artery lesions: Angiographic and intravascular ultrasound outcomes

OBJECTIVES

The aim of this study was to compare the ability of two different atherectomy modalities, the directional atherectomy system (DAS) and the orbital atherectomy system (OAS), to modify plaque and augment luminal gain as evaluated by angiography and intravascular ultrasound (IVUS) in patients with symptomatic femoro-popliteal peripheral arterial disease (PAD).

BACKGROUND

Atherectomy is frequently utilized in the treatment of complex PAD. To date, there are no head-to-head comparisons of existing devices and their selection is based mostly on operator preference rather than on supportive data.

METHODS

This was a single-center, prospective, randomized trial designed to assess the impact of DAS in comparison to OAS on atherosclerotic plaque. Pre- and postatherectomy lesion characterization was performed by angiography and IVUS. Drug-coated balloon (DCB) angioplasty was performed after atherectomy with similar analysis repeated.

RESULTS

Sixty patients were randomized to undergo either DAS or OAS. Pretreatment angiographic and IVUS characteristics were similar in the DAS and OAS groups. DAS led to a greater reduction in plaque volume throughout the entire lesion (5.9% vs. 1.1%, p = 0.003). This corresponded to a greater increase in total vessel and lumen volume by IVUS (161.5 mm³ vs. 50.2 mm³ , p = 0.001; 178.6 mm³ vs. 47.0 mm³ , p = 0.004, respectively), as well as a reduction in angiographic stenosis (40% vs. 70%, p < 0.001). After DCB, 10 patients required stenting for suboptimal results in the OAS group compared with two in the DAS group (p = 0.021).

CONCLUSIONS

Compared to OAS, DAS demonstrated a greater plaque volume reduction and luminal gain with significantly fewer stents needed post-DCB.

Endovascular Treatment and Outcomes for Femoropopliteal In-Stent Restenosis: Insights from the XLPAD Registry

Background

There is limited "real-world" evidence examining treatment modalities and outcomes in patients with symptomatic peripheral arterial disease undergoing endovascular treatment of femoropopliteal (FP) in-stent restenosis (ISR).

Materials and Methods

We compared outcomes in 2,895 patients from the XLPAD registry (NCT01904851) between 2006 and 2019 treated for FP ISR (n = 347) and non-ISR (n = 2,548) lesions. Primary endpoint included major adverse limb events (MALE) at 1 year, a composite of all-cause death, target limb repeat revascularization, or major amputation.

Results

ISR patients were more frequently on antiplatelet (94.5% vs 89.4%, p=0.007) and statin (68.9% vs 60.3%, p=0.003) therapies. Lesion length was similar (ISR: 145 ± 99 mm vs. non-ISR: 142 ± 99 mm, p=0.55). Fewer treated ISR lesions were chronic total occlusions (47.3% vs. 53.7%, p=0.02) and severely calcified (22.4% vs. 44.7%, p < 0.001). Atherectomy (63.5% vs. 45.0%, p < 0.001) and drug-coated balloons (DCB; 4.7% vs. 1.7%, p < 0.001) were more frequently used in ISR lesions. The distal embolization rate was higher in ISR lesions (2.4% vs. 0.9%, p=0.02). Repeat revascularization (21.5% vs. 16.7%, p=0.04; Figure) was higher and freedom from MALE at 1 year was significantly lower (87% vs. 92.5%, p < 0.001) in the ISR group.

Conclusion

Atherectomy and DCB are more frequently used to treat FP ISR lesions. Patients with FP ISR have more intraprocedural distal embolization, higher repeat revascularization procedures, and lower freedom from MALE at 1 year.

Recent Advances in Stent Technology: Do They Reduce Cardiovascular Events?

PURPOSE OF REVIEW

Drug-eluting stents are used in nearly all cases of percutaneous coronary revascularization and have been shown to be superior to balloon angioplasty or bare metal stents. The designs of these stents are continually evolving to maximize efficacy and safety.

RECENT FINDINGS

This review outlines the important components of a drug-eluting stent and highlights the changes in stent design that have led to the optimization of clinical outcomes. Most stents used in contemporary times are thin strut, durable polymer drug-eluting stents (DES) that elute either everolimus or zotarolimus. Newer DES designs incorporating bioresorbable polymers or ultrathin struts have shown encouraging safety and efficacy profiles. DES are essential for the management of patients with obstructive coronary artery disease and are used in most coronary interventions. Changes in stent designs over the past 30 years reflect the ongoing need to address the limitations of earlier stents aimed to improve patient outcomes.

Double-blind, placebo-controlled evaluation of biorest liposomal alendronate in diabetic patients undergoing PCI: The BLADE-PCI trial

BACKGROUND

Diabetes mellitus (DM) is an important predictor of neointimal hyperplasia (NIH) and adverse clinical outcomes after percutaneous coronary intervention (PCI). LABR-312, a novel intravenous formulation of liposomal alendronate, has been shown in animal models to decrease NIH at vascular injury sites and around stent struts. The aim of the Biorest Liposomal Alendronate Administration for Diabetic Patients Undergoing Drug-Eluting Stent Percutaneous Coronary Intervention trial was to assess the safety, effectiveness, and dose response of LABR-312 administered intravenously at the time of PCI withDES in reducing NIH as measured by optical coherence tomography postprocedure in patients with DM.

METHODS

Patients with DM were randomized to a bolus infusion of LABR-312 vs placebo at the time of PCI. Dose escalation of LABR-312 in the study arm was given: 0.01 mg, 0.03 mg, and 0.08 mg. The primary endpoint was the in-stent %NIH volume at 9 months as measured by optical coherence tomography.

RESULTS

From September 2016 to December 2017, 271 patients with DM undergoing PCI were enrolled; 136 patients were randomized to LABR-312 infusion and 135 patients were randomized to placebo. At 9-month follow-up, no difference was seen in the primary endpoint of %NIH between LABR-312 and placebo (13.3% ± 9.2 vs 14.6% ± 8.5, P = .35). No differences were present with the varying LABR-312 doses. Clinical outcomes at 9 months were similar between groups.

CONCLUSIONS

Among patients with DM undergoing PCI with drug-eluting stents, a bolus of LABR-312 injected systematically at the time of intervention did not result in a lower rate in-stent %NIH volume at 9-month follow-up.

The Predictive Value of the Perivascular Adipose Tissue CT Fat Attenuation Index for Coronary In-stent Restenosis

Objectives

To investigate the association between the perivascular adipose tissue (PVAT) fat attenuation index (FAI) derived from coronary computed tomography angiography (CCTA) and the prevalence of in-stent restenosis (ISR) in patients with coronary stent implantation.

Methods

A total of 117 patients with previous coronary stenting referred for invasive coronary angiography (ICA) were enrolled in this retrospective observational analysis. All patients underwent CCTA between July 2016 and November 2021. The deep learning-based (DL-based) method was used to analyze and measure the peri-stent FAI value. Additionally, the relationship between hematological and biochemical parameters collected from all the patients was also explored. The least absolute shrinkage and selection operator (LASSO) method was applied to the most useful feature selection, and binary logistic regression was used to test the association between the selected features and ISR. The predictive performance for ISR of the identified subgroups was evaluated by calculating the area under the curve (AUC) of receiver operator curves plotted for each model. The Pearson correlation coefficient was used to assess the correlation of peri-stent FAI values with degrees of ISR.

Results

The peri-stent FAI values in the ISR group were significantly higher than those in the non-ISR group (−78.1 ± 6.2 HU vs. −87.2 ± 7.3 HU, p < 0.001). The predictive ISR features based on the LASSO analysis were peri-stent FAI, high-density lipoprotein cholesterol (HDL-C), apolipoprotein A1 (ApoA1), and high-sensitivity c-reactive protein (hs-CRP), with an AUC of 0.849, 0.632, 0.620, and 0.569, respectively. Binary logistic regression analysis determined that peri-stent FAI was uniquely and independently associated with ISR after adjusting for other risk factors (odds ratio [OR] 1.403; 95% CI: 1.211 to 1.625; p < 0.001). In the subgroup analysis, the AUCs of the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCx), and right coronary artery (RCA) stents groups were 0.80, 0.87, and 0.96, respectively. The Pearson's correlation coefficient indicated a term moderately correlation between ISR severity and peri-stent FAI values (r = 0.579, P < 0.001).

Conclusions

The peri-stent FAI can be used as an independently non-invasive biomarker to predict ISR risk and severity after stent implantation.

Finite element simulation and optimization of mechanical performance of the magnesium-alloy biliary stent

A biliary stent is used to expand the bile duct during interventional treatment of biliary stricture. To reduce the complications after stent implantation, it is necessary to understand and improve the comprehensive performance of magnesium alloy biliary stents. In this study, at first, the mechanical performance of magnesium alloy biliary stent in bile ducts with different ellipticitiesis studied, and the influence of the ellipticity of bile duct on the interaction of the stent-bile duct coupling system is better understood. Proposed results show the increment of ellipticity of the bile duct will increase the difficulty of expanding the stent. Second, to improve the mechanical performance and degradation performance of the stent simultaneously, an optimal design method based on a zero-order algorithm is used to reduce the maximum equivalent stress on the stent effectively, to make the stress distribution more uniform, and to expand the bile duct of the lesion more effectively and uniformly. The results of this analysis and optimization are useful to predict the clinical effect of stents and to design and optimize stents for both bile duct and other non-vascular.

Drug-eluting stents for the treatment of coronary artery disease: A review of recent advances

INTRODUCTION

Percutaneous coronary intervention is a widely used procedure for the treatment of coronary artery disease to relieve narrowing or occlusion and improve blood supply. Although only balloon angioplasty was performed in the early period, coronary stents were developed later and coronary drug-eluting stents were introduced to decrease in-stent restenosis, which is related to the proliferation and migration of vascular smooth muscle cells.

AREAS COVERED

The drug-eluting stents are composed of a metallic or polymeric platform, specific drug, and polymers or coating for drug release. In this article, the recent advances in drug-eluting stent technologies for the treatment of coronary artery disease and adjunctive antiplatelet therapy after drug-eluting stent implantation will be reviewed.

EXPERT OPINION

The need for further advances in drug-eluting stents or fully bioresorbable coronary scaffolds still exists to improve patient survival or clinical outcomes. The use for different actions or of combinations of drugs with several actions can be potential. Technological refinement and progress in manufacturing to improve mechanical integrity are needed, particularly for fully bioresorbable scaffolds. For antiplatelet therapy after stenting, clinical bleeding reduction strategies, such as a shortened duration of dual-antiplatelet therapy, are in progress.

Diabetes and restenosis

Restenosis, defined as the re-narrowing of an arterial lumen after revascularization, represents an increasingly important issue in clinical practice. Indeed, as the number of stent placements has risen to an estimate that exceeds 3 million annually worldwide, revascularization procedures have become much more common. Several investigators have demonstrated that vessels in patients with diabetes mellitus have an increased risk restenosis. Here we present a systematic overview of the effects of diabetes on in-stent restenosis. Current classification and updated epidemiology of restenosis are discussed, alongside the main mechanisms underlying the pathophysiology of this event. Then, we summarize the clinical presentation of restenosis, emphasizing the importance of glycemic control in diabetic patients. Indeed, in diabetic patients who underwent revascularization procedures a proper glycemic control remains imperative.

Characterizing the Mechanical Performance of a Bare-Metal Stent with an Auxetic Cell Geometry

This study develops and characterizes the distinctive mechanical features of a stainless-steel metal stent with a tailored structure. A high-precision femtosecond laser was used to micromachine a stent with re-entrant hexagonal (auxetic) cell geometry. We then characterized its mechanical behavior under various mechanical loadings using in vitro experiments and through finite element analysis. The stent properties, such as the higher capability of the stent to bear upon bending, exceptional advantage at elevated levels of twisting angles, and proper buckling, all ensured a preserved opening to maintain the blood flow. The outcomes of this preliminary study present a potential design for a stent with improved physiologically relevant mechanical conditions such as longitudinal contraction, radial strength, and migration of the stent.

Colchicine for symptomatic coronary artery disease after percutaneous coronary intervention

BACKGROUND

Percutaneous coronary intervention (PCI), the preferred coronary reperfusion strategy, induces endothelial trauma which may mount an inflammatory response. This has been shown to increase the likelihood of further major adverse cardiovascular events (MACE). Colchicine, a cheap and widely used anti-inflammatory has shown promise in improving cardiovascular outcomes. We aimed to perform a systematic review and meta-analysis to study the effects of colchicine in patients with symptomatic coronary artery disease (CAD) who have undergone PCI.

METHOD

We systematically reviewed and meta-analysed 7 randomised controlled trials including a total of 6660 patients (colchicine group: 3347, control group: 3313; mean age=60.9±10). Six studies included participants who had a ≤13.5-day history of acute coronary syndrome (ACS). One study included patients with both ACS and chronic coronary syndrome. The follow-up of studies ranged from 3 days to 22.6 months.

RESULTS

The use of colchicine in patients who underwent PCI significantly reduced MACE outcomes (risk ratio 0.73 (95% CI 0.61 to 0.87); p=0.0003) with minimal heterogeneity across the analysis (I²=6%; P for Cochran Q=0.38). These results were driven mainly by the reduction in repeat vessel revascularisation, stroke and stent thrombosis. The number needed to treat to prevent one occurrence of MACE was 41.

CONCLUSION

Colchicine significantly reduced the risk of MACE in patients with CAD who underwent PCI, mostly in the reduction of repeat vessel revascularisation, stroke and stent thrombosis. The efficacy of colchicine should be further studied by distinguishing its use alongside different stent types and dosing regimens.

PROSPERO REGISTRATION NUMBER

CRD42021245699.

Application of drug-coated balloons for intracranial atherosclerosis disease: a systematic review

BACKGROUND

Although percutaneous transluminal angioplasty and stenting (PTAS) was an effective and safe alternative treatment for severe intracranial atherosclerosis disease (ICAD), the high rate of restenosis remained a major issue for this endovascular procedure. Recently, the application of drug-coated balloons (DCB) in ICAD was developed to reduce restenosis. This systematic review aimed to evaluate the efficacy and safety of DCB angioplasty for ICAD.

METHODS

We searched relevant databases for eligible studies enrolling ICAD patients treated with DCB. The event rates of restenosis and periprocedural complications in the follow-up period were pooled with random-/fixed-effect models using Freeman-Tukey double arcsine transformation. Heterogeneity tests and publication bias tests were performed.

RESULTS

Two hundred and twenty-four ICAD patients treated with DCB from 9 eligible studies were included. Rate of stenosis in the DCB arm before treatment was ranged from 62% to 90% and reported median follow-up was ranged from 3 to 10.7 months. The pooled incidence of restenosis were 5.7% (95% confidence interval [CI] 2.6%-9.7%; I² = 0%, p = 0.516) and 5.9% for periprocedural complications (95% CI: 2.5-10.3%; I² = 0%, p = 0.649) in follow-up term.

CONCLUSION

With the limitation of the low quality of the available evidence, angioplasty with DCB appears to be effective and safe in severe ICAD. Further larger randomized trials are needed to provide more definitive evidence and to address the ideal clinical context for their application.

A First-in-Man Clinical Evaluation of Sirolimus and Ascorbic Acid-Eluting Stent Systems: a Multicenter, Subject-Blinded, Randomized Study

This prospective, multi-center, randomized, comparative, and pivotal clinical study in patients with coronary artery occlusive disease was conducted to evaluate the safety and efficacy of D+Storm™ drug-eluting stent (DES), a sirolimus-eluting stent coated with polylactic acid and ascorbic acid. Our results showed that in-segment late lumen loss of D+Storm™ DES group was non-inferior to BioMatrix Flex™ DES group and the total procedural success rate of D+Storm™ DES group was 100%. In addition, the safety of the D+Storm™ DES group at 36 weeks was also demonstrated in this study.

Background and Objectives

This clinical trial was conducted to evaluate the safety and efficacy of D+Storm™ drug-eluting stent (DES) and BioMatrix Flex™ DES.

Methods

This study was a multicenter, subject-single-blind, randomized, and confirmed comparative clinical trial. According to the inclusion criteria, those diagnosed with stable angina, unstable angina, silent ischemia, or non-ST-segment myocardial infarction were selected among patients with coronary artery stenosis as subjects. Among the subjects with 50% stenosis on coronary angiography, the experiment was performed on those who had a lesion with reference vessel 2.5–4.0 mm in diameter and ≤40 mm in length. The primary endpoint was an in-segment late loss and the secondary endpoints were in-stent late lumen loss, stent malapposition, the incidence of mortality, myocardial infarction, reoperation, and stent thrombosis at 36 weeks.

Results

57 patients in the D+Storm™ DES group and 55 patients in the BioMatrix Flex™ DES group were enrolled in the study. Fifty-seven patients in the D+Storm™ DES group and Fifty-five patients in the BioMatrix Flex™ DES group were enrolled in the study. An average of in-segment late lumen loss was 0.08±0.13 mm in the D+Storm™ DES group and 0.14±0.32 mm in the BioMatrix Flex™ DES group with no significant difference between the 2 groups (p=0.879). In addition, there was no significant difference in adverse events between D+Storm™ DES and BioMatrix Flex™ DES.

Conclusions

This study demonstrated the clinical effectiveness and safety of D+Storm™ DES implantation in patients with coronary artery disease over a 36-week follow-up period.

The Clinical Efficacy Analysis of Treatment With a Willis Covered Stent in Traumatic Pseudoaneurysm of the Internal Carotid Artery

Objective: To investigate the safety and efficacy of Willis covered stents (WCS) in the treatment of traumatic pseudoaneurysm of the cranial internal carotid artery (CICA).

Methods: Fifteen patients with traumatic pseudoaneurysm of the intracranial segment of the ICA treated with the WCS system at our institution from 2013 to 2019 were analyzed retrospectively. Follow-up observation and digital subtraction angiography (DSA) examination were conducted ~6 months after the treatment.

Results: DSA performed immediately after stent deployment revealed that complete occlusion of the lesion was achieved in 13 patients and that endoleak occurred in two patients. In 12 patients, postoperative DSA examination indicated that the lesions were completely occluded. In two patients who had a second stent implantation at the break of the ICA, traumatic ICA rupture was essentially completely obstructed in 1 patient. The endoleak remained in one patient with carotid cavernous sinus fistula because the placement of the second stent system was difficult with his ICA tortuosity. No recurrence of aneurysms, hemorrhage, or other lesions was observed, and the patients' parent arteries were patent without stenosis. No procedure-related complications or ischemic strokes occurred during the follow-up period of ~6 months.

Conclusions: For treatment of traumatic pseudoaneurysm of the CICA, Willis covered stent implantation in some appropriate cases, is safe and effective. However, large-sample controlled studies and multicenter studies are needed for further confirmation.

Microneedle-mediated therapy for cardiovascular diseases

Cardiovascular diseases remain a leading cause of global disease burden. To date, the limited drug delivery efficacy confines the therapeutic effect in most conventional approaches, such as intramyocardial injections and vascular devices, due to short-term drug release and low retention within the disease sites. As a typical transdermal medical device with a minimally invasive manner and controlled/sustained drug release pattern, microneedles have gained momentum in the field of cardiovascular therapy, from which several cardiovascular diseases have been benefited to the ultimate therapeutic effects. In this concise review, strategies based on the microneedles for the treatments of cardiovascular diseases are introduced, mainly focus on hypertension, atherosclerosis, thrombus, and myocardial diseases. The limitations at the present stage and perspectives of the next-generation microneedles for cardiovascular therapy are also discussed.

Impact of chronic kidney disease on long-term outcomes for coronary in-stent restenosis after drug-coated balloon angioplasty

BACKGROUND

Patients with chronic kidney disease (CKD) and coronary instent restenosis (ISR) treated with drug-coated balloon (DCB) angioplasty have been excluded from randomized controlled trials. We aimed to investigate the clinical impact of CKD stratified by severity, on clinical outcomes for patients with ISR treated with DCB angioplasty.

METHODS

This cohort study enrolled 1,376 patients treated with DCB angioplasty; 639 CKD patients defined as having an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 and 737 patients with preserved renal function were identified. Risks of target vessel failure (TVF), all-cause mortality, and any repeated revascularization were analyzed.

RESULTS

The CKD group had a significantly higher risk of TVF [adjusted hazard ratio (HR): 1.337; 95% confidence interval (CI): 1.125-1.590; p = 0.0010], all-cause mortality (adjusted HR: 2.553; 95% CI: 1.494-4.361; p = 0.0006), and any repeated revascularization (adjusted HR: 1.447; 95% CI: 1.087-1.927; p = 0.0114) compared with the non-CKD group. After multivariable adjustment, patients with severe CKD (eGFR = 15-29 mL/min/1.73 m2) and end-stage renal disease (ESRD) (eGFR <15 mL/min/1.73 m2) had a significantly higher risk of adverse events comparable to that in patients with preserved renal function.

CONCLUSIONS

In this cohort study, patients with CKD and ISR undergoing DCB angioplasty had a significantly higher risk of adverse events compared with patients with preserved renal function, whereas subgroups with mild to moderate CKD did not display this difference. Different revascularization strategies may be considered for patients with severe CKD or ESRD with ISR.

Numerical Analysis for Non-Uniformity of Balloon-Expandable Stent Deployment Driven by Dogboning and Foreshortening

PURPOSE

Stenting is the most common intervention for arteriosclerosis treatment; however, the success of the treatment depends on the incidence of in-stent restenosis (ISR). Stent deployment characteristics are major influencers of ISR and can be measured in terms of dogboning, asymmetry, and foreshortening. This study aimed to analyse the implications of balloon and stent-catheter assembly parameters on the stent deployment characteristics.

METHODS

Experimental approach to analyse the impact of the balloon and stent-catheter assembly parameters on stent deployment characteristics is a time-consuming and complex task, whereas numerical methods prove to be quick, efficient, and reliable. In this study, eleven finite element models were employed to analyse non-uniform balloon stent expansion pattern, comprised of variation in, stent axial position on balloon, balloon length, balloon folding pattern, and balloon wall thickness.

RESULTS

Obtained results suggest that the axially noncentral position of the stent on balloon and variable balloon thickness lead to non-uniform stent deployment pattern. Also, it was proved that variation in balloon length and balloon folding pattern influence deployment process.

CONCLUSION

Improved positional accuracies, uniform balloon wall thickness, and selection of the appropriate length of a balloon for selected stent configuration will help to minimize dogboning, asymmetry, and foreshortening during non-uniform stent expansion, thereby reducing the risk of restenosis. The stated numerical approach will be helpful to optimize stent catheter assembly parameters thus minimizing in-vitro tests and product development time.

New antithrombotic strategies and coronary stent technologies for patients at high bleeding risk undergoing percutaneous coronary intervention

Patients at high bleeding risk (HBR) are a sizable part of the population undergoing percutaneous coronary intervention (PCI) and stent implantation. This population historically lacks standardized definition, thus limiting trial design, data generalizability, and clinical decision-making. To overcome this limitation the Academic Research Consortium (ARC) has recently released comprehensive guidelines defining HBR criteria for study design purpose and daily clinical practice. Furthermore, several risk scores have been developed aiming to discriminate HBR patients and support physicians for clinical decision making when faced with this complex subset of patients. Accordingly, the first part of this review article will explore guideline-recommended risk scoring as well as ARC-HBR criteria and their relative application for daily clinical practice. The second part of this review article will explore the complex interplay between risk of bleeding, and coronary thrombotic events in patients deemed at HBR. Indeed, several features that identify these patients, are also independent predictors of recurrent ischemic events, thus challenging revascularization strategies and optimal antithrombotic therapy. Accordingly, several clinical trials have been conducted to evaluate the safety and efficacy of the new generation of coronary platforms and different antithrombotic strategies for HBR patients to minimize both ischemic and bleeding events. Accordingly, in this part we discuss current guidelines, trials and observational data evaluating antithrombotic strategies and stent technologies for patients at HBR.

Usefulness of black-blood magnetic resonance angiography generated from vessel wall imaging after the stent-assisted treatment of intracranial arterial diseases

PURPOSE

After stent-assisted treatment for intracranial diseases, three-dimensional time-of-flight magnetic resonance angiography is a noninvasive follow-up method, but susceptibility artifacts prevent accurate evaluations of stented arteries. Sampling perfection with application-optimized contrast using different flip angle evolution (SPACE) sequence often used for vessel wall imaging is less susceptible to susceptibility artifacts, since it is a spin-echo sequence. Hence, we evaluated the feasibility of black-blood magnetic resonance angiography generated from vessel wall imaging data obtained using the SPACE sequence in the depiction of stented arteries by comparing with three-dimensional time-of-flight magnetic resonance angiography and digital subtraction angiography.

METHODS

Our study group comprised 11 consecutive patients. For both three-dimensional time-of-flight magnetic resonance angiography and black-blood magnetic resonance angiography, the contrast ratio obtained from the stented artery and the normal artery proximal to the stent were calculated. And the depiction of stented arteries was visually evaluated. Additionally, the relative diameter index obtained from the stented artery and the normal artery proximal to the stent were calculated for three-dimensional time-of-flight magnetic resonance angiography, black-blood magnetic resonance angiography and digital subtraction angiography.

RESULTS

The contrast ratio of the stented artery was significantly lower than that of the normal artery on three-dimensional time-of-flight magnetic resonance angiography, but no significant difference was seen using black-blood magnetic resonance angiography. Regarding both the diameter index and the visual assessment score, black-blood magnetic resonance angiography was significantly better than three-dimensional time-of-flight magnetic resonance angiography. On black-blood magnetic resonance angiography, the diameter index was equal to that of digital subtraction angiography, and the flow signal was homogeneous and continuous in most the cases.

Durable endothelium-mimicking coating for surface bioengineering cardiovascular stents

Mimicking the nitric oxide (NO)-release and glycocalyx functions of native vascular endothelium on cardiovascular stent surfaces has been demonstrated to reduce in-stent restenosis (ISR) effectively. However, the practical performance of such an endothelium-mimicking surfaces is strictly limited by the durability of both NO release and bioactivity of the glycocalyx component. Herein, we present a mussel-inspired amine-bearing adhesive coating able to firmly tether the NO-generating species (e.g., Cu-DOTA coordination complex) and glycocalyx-like component (e.g., heparin) to create a durable endothelium-mimicking surface. The stent surface was firstly coated with polydopamine (pDA), followed by a surface chemical cross-link with polyamine (pAM) to form a durable pAMDA coating. Using a stepwise grafting strategy, Cu-DOTA and heparin were covalently grafted on the pAMDA-coated stent based on carbodiimide chemistry. Owing to both the high chemical stability of the pAMDA coating and covalent immobilization manner of the molecules, this proposed strategy could provide 62.4% bioactivity retention ratio of heparin, meanwhile persistently generate NO at physiological level from 5.9 ± 0.3 to 4.8 ± 0.4 × 10⁻¹⁰ mol cm⁻² min⁻¹ in 1 month. As a result, the functionalized vascular stent showed long-term endothelium-mimicking physiological effects on inhibition of thrombosis, inflammation, and intimal hyperplasia, enhanced re-endothelialization, and hence efficiently reduced ISR.

•

A durable endothelium-mimicking coating was developed for surface bioengineering of cardiovascular stents.

•

The durable endothelium-mimicking surface was realized by stepwise grafting of Cu-DOTA and heparin on a robust coating.

•

The durable endothelium-mimicking coating endows the vascular stents with ability to dramatically reduce restenosis.

Carotid Artery Atherosclerotic Profile as Risk Predictor for Restenosis After Coronary Stenting

BACKGROUND

The incidence of restenosis of the coronary artery after a bare-metal stent implant has been lower than in simple balloon angioplasty; however, it still shows relatively high rates.

OBJECTIVE

The aim of this study was to find new risk indicators for in-stent restenosis using carotid ultrasonography, that, in addition to the already existing indicators, would help in decision-making for stent selection.

METHODS

We carried out a cross-sectional prospective study including 121 consecutive patients with chronic coronary artery disease who had undergone percutaneous coronary intervention with repeat angiography in the previous 12 months. After all cases of in-stent restenosis were identified, patients underwent carotid ultrasonography to evaluate carotid intima-media thickness and atherosclerosis plaques. The data were analyzed by Cox multiple regression. The significance level was set a p<0.05.

RESULTS

Median age of patients was 60 years (1st quartile = 55, 3rd quartile = 68), and 64.5% of patients were male. Coronary angiography showed that 57 patients (47.1%) presented in-stent restenosis. Fifty-five patients (45.5%) had echolucent atherosclerotic plaques in carotid arteries and 54.5% had echogenic plaques or no plaques. Of patients with who had echolucent plaques, 90.9% presented coronary in-stent restenosis. Of those who had echogenic plaques or no plaques, 10.6% presented in-stent restenosis. The presence of echolucent plaques in carotid arteries increased the risk of coronary in-stent restenosis by 8.21 times (RR=8.21; 95%CI: 3.58-18.82; p<0.001).

CONCLUSIONS

The presence of echolucent atherosclerotic plaques in carotid artery constitutes a risk predictor of coronary instent restenosis and should be considered in the selection of the type of stent to be used in coronary angioplasty.

Investigating the material modelling of a polymeric bioresorbable scaffold via in-silico and in-vitro testing

The accurate material modelling of poly-l-lactic acid (PLLA) is vital in conducting finite element analysis of polymeric bioresorbable scaffolds (BRS) to investigate their mechanical performance and seek improved scaffold designs. To date, a large variety of material models have been utilised, ranging from simple elasto-plastic models to high fidelity parallel network models. However, no clear consensus has been reached on the appropriateness of these different models and whether simple, less computationally expensive models can serve as acceptable approximations. Therefore, we present a study which explored the use of different isotropic and anisotropic elasto-plastic models in simulating the balloon expansion and radial crushing of the thin-strut (sub-100 μm) ArterioSorb^TM BRS using the Abaqus/Explicit (DS SIMULIA) solution method. Stress-strain data was obtained via tensile tests at two different displacement rates. The use of isotropic and transversely isotropic elastic theories was explored, as well as the implementation of stress relaxation in the plastic regime of the material. The scaffold performance was quantified via its post-expansion diameter, percentage recoil and radial strength. The in-silico results were validated via comparison with in-vitro data of an analogous bench test. Accurately predicting both the post-expansion scaffold shape and radial strength was found to be challenging using the in-built Abaqus models. Therefore, a novel user-defined material model was developed via the VUMAT subroutine which improved functionality by facilitating a variable yield ratio, dependent upon the plastic strain as well as stress relaxation in overly strained elements. This achieved prediction of the radial strength within 1.1% of the in-vitro results and the scaffold's post-expansion diameter within 6.7%. A realistic multi-balloon simulation strategy was also used which confirmed that a mechanism exists in the PLLA which facilitates the extremely low percentage recoil behaviour observed in the ArterioSorb^TM BRS. This could not be captured by the aforementioned material property models.

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.