Predictors of stent thrombosis and their implications for clinical practice

Identification of endothelial protein C receptor as a novel druggable agonistic target for reendothelialization promotion and thrombosis prevention of eluting stent

The commercially available drug-eluting stent with limus (rapamycin, everolimus, etc.) or paclitaxel inhibits smooth muscle cell (SMC), reducing the in-stent restenosis, whereas damages endothelial cell (EC) and delays stent reendothelialization, increasing the risk of stent thrombosis (ST) and sudden cardiac death. Here we present a new strategy for promoting stent reendothelialization and preventing ST by exploring the application of precise molecular targets with EC specificity. Proteomics was used to investigate the molecular mechanism of EC injury caused by rapamycin. Endothelial protein C receptor (EPCR) was screened out as a crucial EC-specific effector. Limus and paclitaxel repressed the EPCR expression, while overexpression of EPCR protected EC from coating (eluting) drug-induced injury. Furthermore, the ligand activated protein C (APC), polypeptide TR47, and compound parmodulin 2, which activated the target EPCR, promoted EC functions and inhibited platelet or neutrophil adhesion, and enhanced rapamycin stent reendothelialization in the simulated stent environment and in vitro. In vivo, the APC/rapamycin-coating promoted reendothelialization rapidly and prevented ST more effectively than rapamycin-coating alone, in both traditional metal stents and biodegradable stents. Additionally, overexpression or activation of the target EPCR did not affect the cellular behavior of SMC or the inhibitory effect of rapamycin on SMC. In conclusion, EPCR is a promising therapeutical agonistic target for pro-reendothelialization and anti-thrombosis of eluting stent. Activation of EPCR protects against coating drugs-induced EC injury, inflammatory cell, or platelet adhesion onto the stent. The novel application formula for APC/rapamycin-combined eluting promotes stent reendothelialization and prevents ST.

Considerations in Antiplatelet Therapy in Women Undergoing Treatment of Acute Coronary Syndrome or Percutaneous Coronary Intervention

Antiplatelet therapy is integral to reduce the risk of future ischemic events following acute coronary syndrome (ACS) or percutaneous coronary intervention (PCI); this aim must be balanced by limiting the risk of bleeding. Women with ACS or undergoing PCI have distinct platelet physiology, vascular anatomy, and clinical profiles that can influence the selection of an appropriate regimen. There are procedural techniques that can enhance safety in women. The poor inclusion of women in ACS and PCI trials limits our understanding of the ideal antiplatelet regimen in women, and future studies must find ways to increase the participation of female patients.

Strategies to optimize initial P2Y12 inhibitor therapy in STEMI patients

INTRODUCTION

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is the standard of care for patients who undergo percutaneous coronary intervention (PCI) for ST elevation myocardial infarction (STEMI). Though this regimen reduces rates of ischemic events in patients with STEMI, the optimal strategy for P2Y12 administration in STEMI patients is still evolving.

PURPOSE

The purpose of this review is to summarize current evidence on optimal use of ticagrelor and prasugrel in the acute phase of STEMI.

SUMMARY

Due to high platelet activity in the acute setting of STEMI and PCI, adequate and rapid platelet inhibition is important. Strategies of increased ticagrelor/prasugrel loading dose or earlier administration in STEMI have not been successful in closing this platelet inhibition gap. Potential strategies for improving ticagrelor/prasugrel use early in STEMI include bridging with intravenous antiplatelet agents or crushed or chewed administration.

CONCLUSION

Oral ticagrelor/prasugrel given before or immediately after STEMI PCI is usually sufficient to prevent thrombotic complications. When faster platelet inhibition is desired, or oral administration is compromised by inability to swallow tablets, crushing/chewing ticagrelor/prasugrel tablets is an alternative to intravenous P2Y12 inhibitor therapy.

NONRATT000538.2 promotes vascular smooth muscle cell phenotypic switch and in-stent restenosis

Vascular smooth muscle cell (VSMC) excessive proliferation and migration are considered the main pathological process in in-stent restenosis (ISR) following vascular intervention. Certain long noncoding RNAs play vital roles in this process. Therefore, this study aimed to explore novel regulators for ISR and further uncover the mechanism. Using a rat abdominal aorta stent implantation model, we observed that NONRATT000538.2 (NR538.2) served as a positive regulator for VSMC proliferation and migration. By manipulating NR538.2 expression via adenoviral overexpression or siRNA knockdown, we noted that NR538.2 promoted VSMC phenotypic switching, thereby inducing proliferation and migration. Significantly, the local delivery of siRNA of NR538.2 via adeno-associated virus vector suppressed balloon injury-induced neointima formation. Our study demonstrated for the first time that NR538.2 positively influenced VSMC proliferation during ISR.

Intravascular imaging-guided versus angiography-guided percutaneous coronary intervention: a systematic review and bayesian network meta-analysis of randomized controlled trials

BACKGROUND

Percutaneous coronary intervention (PCI) has become one of the most commonly performed interventional life-saving procedures worldwide. Intravascular Imaging (intravascular ultrasound (IVUS) and optical coherence tomography (OCT)) have initially evolved to guide PCI compared with angiography. However, this technology is not universally employed in all PCI procedures, and there is ongoing controversy regarding its additional benefits to patient outcomes. We aim to estimate the efficacy and safety of imaging modalities during PCI, allowing pre-, per, and post-intervention assessment of coronary vascularization.

METHODS

A systematic review and Bayesian network meta-analysis of randomized controlled trials (RCTs), which were retrieved from PubMed, WOS, SCOPUS, EMBASE, and CENTRAL through September 2023. We used R, version 4.2.0. Effect sizes will be presented as odds ratios with accompanying 95% credible intervals.

PROSPERO ID

CRD42024507821.

RESULTS

Our study, encompassing 36 RCTs with a total of 17,572 patients, revelead that compared to conventional angiography, IVUS significantly reduced the risk of major adverse cardiovascular events (MACE) (OR: 0.71 [95% CrI: 0.56 to 0.87]) but not OCT (OR: 0.91 [95% CrI: 0.62 to 1.39]), IVUS and OCT significantly reduced the risk of cardiac death (OR: 0.50 [95% CrI: 0.33 to 0.76]) and (OR: 0.55 [95% CrI: 0.31 to 0.98]), respectively, IVUS significantly reduced the risk of target vessel-related revascularization (OR: 0.60 [95% CrI: 0.48 to 0.75]) but not OCT (OR: 0.86 [95% CrI: 0.60 to 1.19]), IVUS and OCT significantly reduced the risk of stent thrombosis (OR: 0.50 [95% CrI: 0.28 to 0.92]) and (OR: 0.48 [95% CrI: 0.22 to 0.98]), respectively, IVUS significantly reduced the risk of re-stenosis (OR: 0.65 [95% CrI: 0.46 to 0.88]) but not OCT (OR: 0.55 [95% CrI: 0.15 to 1.99]), neither IVUS (OR: 0.97 [95% CrI: 0.71 to 1.38]) nor OCT (OR: 0.75 [95% CrI: 0.49 to 1.22]) were associated with statistically significant reductions in all-cause mortality, neither IVUS (OR: 0.70 [95% CrI: 0.45 to 1.32]) nor OCT (OR: 0.81 [95% CrI: 0.47 to 1.59]) were associated with statistically significant reductions in target vessel failure, neither IVUS (OR: 0.88 [95% CrI: 0.43 to 2.44]) nor OCT (OR: 0.81 [95% CrI: 0.37 to 2.04]) were associated with statistically significant reductions in target lesion failure, and neither IVUS (OR: 0.82 [95% CrI: 0.60 to 1.06]) nor OCT (OR: 0.84 [95% CrI: 0.59 to 1.19]) were associated with statistically significant reductions in myocardial infarction.

CONCLUSION

Intravascular imaging-guided, including IVUS and OCT, improved the postinterventional outcomes of PCI, notably suggesting their advantage over traditional angiography with no significant difference between IVUS and OCT.

Lipid profile and risk factors for neoatherosclerosis after drug-eluting stent implantation in acute coronary syndrome

BACKGROUND

Predictors of neoatherosclerosis in patients who received primary percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) remain unclear.

OBJECTIVE

The aim of this study is to investigate the frequency and risk factors of neoatherosclerosis 1-year after the onset of ACS.

METHODS

This study investigated 83 patients who underwent PCI for ACS followed by 1-year follow-up optical coherence tomography. The patients were categorized into the neoatherosclerosis (n = 11) and non-neoatherosclerosis groups (n = 72). Baseline characteristics, PCI procedures, medical therapies, and blood tests at 1-year, including detailed lipid profiles, were compared between the two groups.

RESULTS

Diabetes mellitus was more prominent in the neoatherosclerosis than in the non-neoatherosclerosis group (45% vs. 17 %, respectively, p = 0.03). Total cholesterol (171 ± 37 mg/dL vs. 145 ± 25 mg/dL, respectively, p < 0.01), non-high-density lipoprotein cholesterol (HDL-C) (124 ± 36 mg/dL vs. 94 ± 24 mg/dL, respectively, p < 0.01), low-density lipoprotein cholesterol (94 ± 36 mg/dL vs. 72 ± 19 mg/dL, respectively, p < 0.01), and lipoprotein (a) (Lp[a]) (70 [19-112] mg/dL vs. 10 [3-25] mg/dL, respectively, p = 0.03) at follow-up were significantly higher in the neoatherosclerosis group. Multivariate analysis revealed that neoatherosclerosis was associated with high serum non-HDL-C (odds ratio [OR]: 1.075; 95 % confidence interval [CI]: 1.011-1.144; p < 0.01) and high serum Lp(a) levels (>30 mg/dL) (OR: 11.0; 95 % CI: 1.492-81.02; p = 0.02).

CONCLUSION

Poorly controlled non-HDL-C and Lp(a) would be risk factors of neoatherosclerosis in patients 1-year after ACS.

Influence of stent strut and its associated injury on thrombus formation: A dissipative particle dynamics study

Vascular stent intervention is a pivotal treatment for coronary atherosclerosis, though in-stent thrombosis remains a significant postoperative complication with an unclear underlying mechanism. This study utilized dissipated particle dynamics analysis to investigate the impact of stent and its injury on platelet behavior. The findings suggest that thrombus formation upstream of the stent is mainly initiated by upstream arterial injury, which leads to increased platelet accumulation and activation in that area. While thrombosis downstream of the stent is more directly influenced by the stent itself. The morphology and size of in-stent thrombosis can vary significantly due to the different contributions of the stent and underlying injuries. Additionally, the volume of in-stent thrombosis is affected by the extent of the injury and the viscosity of platelets, showing a notable increase in volume with the lengthening of the injury area and rise in platelet viscosity. This study provides a novel theoretical framework for optimizing stent placement strategies and structural designs by examining the effects of stent struts and associated injuries on thrombus formation.

Innovations in Intracoronary Imaging: Present Clinical Practices and Future Outlooks

Engaging intracoronary imaging (IC) techniques such as intravascular ultrasound or optical coherence tomography enables the precise description of vessel architecture. These imaging modalities have well-established roles in providing guidance and optimizing percutaneous coronary intervention (PCI) outcomes. Furthermore, IC is increasingly recognized for its diagnostic capabilities, as it has the unique capacity to reveal vessel wall characteristics that may not be apparent through angiography alone. This manuscript thoroughly reviews the contemporary landscape of IC in clinical practice. Focused on current methodologies, the review explores the utility and advancements in IC techniques. Emphasizing their role in clarifying coronary pathophysiology, guiding PCI, and optimizing patient outcomes, the manuscript critically evaluates the strengths and limitations of each modality. Additionally, the integration of IC into routine clinical workflows and its impact on decision-making processes are discussed. By synthesizing the latest evidence, this review provides valuable insights for clinicians, researchers, and healthcare professionals involved in the dynamic field of interventional cardiology.

Polymer-free stents for percutaneous coronary intervention in diabetic patients: a systematic review and meta-analysis

Aim: To compare the efficacy of polymer-free drug-eluting stents (PF-DES) versus other stents in diabetic patients with coronary artery disease undergoing percutaneous coronary interventions.Materials & methods: A systematic review and meta-analysis were performed to identify pertinent randomized controlled trials. The primary end point was the occurrence of target lesion failure.Results: Eight randomized controlled trials were included for a total of 4854 subjects. The PF-DES group experienced a trend in favor of a lower rate of target lesion failure (Incidence rate ratio = 0.91; p = 0.11) and a significantly lower rate of cardiac mortality, as compared with the control group (Incidence rate ratio = 0.82; p = 0.04). However, statistical significance was lost if bare-metal stent patients were excluded and a trend in favor of the PF-DES strategy was reported only for cardiac mortality.Conclusion: PF-DES could be a valuable strategy in diabetic patients with coronary artery disease undergoing percutaneous coronary interventions.

How I treat the co-occurrence of venous and arterial thromboembolism: anticoagulation, antiplatelet therapy, or both?

ABSTRACT

Arterial and venous thromboses are classically considered distinct disease states, with arterial thrombosis mediated predominantly by platelets and therefore, treated with antiplatelet therapy, and venous thrombosis mediated by the plasmatic coagulation system and treated with anticoagulation. However, co-occurrence of arterial and venous events is common, and there is increasing evidence of shared risk factors and pathophysiologic overlap. This presents a management challenge: does the patient with venous and arterial thrombosis, require anticoagulation, antiplatelet therapy, or both? Herein, we present a structured approach to the evaluation and management of patients with venous thrombosis who are also at risk for or have a history of an arterial thromboembolic event. We emphasize the importance of defining the indications for antithrombotic therapy, as well as the evaluation of factors that influence both thrombotic and bleeding risk, including disorder-specific and patient-specific factors, as well as the inherent risk balance of antithrombotic therapy regimens. We illustrate this approach in 4 cases, discussing the unique considerations and recent updates in the management of venous thrombosis, acute noncardioembolic ischemic stroke, coronary artery disease and acute myocardial infarction, and peripheral artery disease after revascularization.

Aspirin hypersensitivity: a practical guide for cardiologists

Aspirin has been known for a long time and currently stays as a cornerstone of antithrombotic therapy in cardiovascular disease. In patients with either acute or chronic coronary syndromes undergoing percutaneous coronary intervention aspirin is mandatory in a dual antiplatelet therapy regimen for prevention of stent thrombosis and/or new ischaemic events. Aspirin is also currently a first-option antithrombotic therapy after an aortic prosthetic valve replacement and is occasionally required in addition to oral anticoagulants after implantation of a mechanical valve. Presumed or demonstrated aspirin hypersensitivity is a main clinical problem, limiting the use of a life-saving medication. In the general population, aspirin hypersensitivity has a prevalence of 0.6%-2.5% and has a plethora of clinical presentations, ranging from aspirin-exacerbated respiratory disease to anaphylaxis. Although infrequent, when encountered in clinical practice aspirin hypersensitivity poses for cardiologists a clinical dilemma, which should never be trivialized, avoiding-as much as possible-omission of the drug. We here review the epidemiology of aspirin hypersensitivity, provide an outline of pathophysiological mechanisms and clinical presentations, and review management options, starting from a characterization of true aspirin allergy-in contrast to intolerance-to suggestion of desensitization protocols.

Pharmacologic targeting of coagulation factors XII and XI by monoclonal antibodies reduces thrombosis in nitinol stents under flow

BACKGROUND

Cardiovascular implantable devices, such as vascular stents, are critical for the treatment of cardiovascular diseases. However, their success is dependent on robust and often long-term antithrombotic therapies. Yet, the current standard-of-care therapies often pose significant bleeding risks to patients. Coagulation factor (F)XI and FXII have emerged as potentially safe and efficacious targets to safely reduce pathologic thrombin generation in medical devices.

OBJECTIVES

To study the efficacy of monoclonal antibody-targeting FXII and FXI of the contact pathway in preventing vascular device-related thrombosis.

METHODS

The effects of inhibition of FXII and FXI using function-blocking monoclonal antibodies were examined in a nonhuman primate model of nitinol stent-related thrombosis under arterial and venous flow conditions.

RESULTS

We found that function-blocking antibodies of FXII and FXI reduced markers of stent-induced thrombosis in vitro and ex vivo. However, FXI inhibition resulted in more effective mitigation of thrombosis markers under varied flow conditions.

CONCLUSION

This work provides further support for the translation of contact pathway of coagulation inhibitors for their adjunctive clinical use with cardiovascular devices.

Procedural and one-year outcomes following drug-eluting stent and drug-coated balloon combination for the treatment of de novo diffuse coronary artery disease: the HYPER Study

BACKGROUND

De novo diffuse coronary artery disease (CAD) is a challenging scenario in interventional cardiology with limited treatment option, beside stent implantation. In this context, a hybrid approach, combining the use of drug-eluting stent (DES) and drug-coated balloon (DCB) to treat different segments of the same lesion (e.g. long lesion and/or true bifurcation), might be an interesting and alternative strategy to limit the metal amount. The aim of this study was to evaluate the safety and efficacy of a hybrid approach in addressing percutaneous treatment of de novo diffuse CAD.

METHODS

This was a prospective, multicenter study including patients affected by de novo diffuse CAD treated with a hybrid approach from April 2019 to December 2020. Angiographic and clinical data were collected. The primary endpoint was the one-year device-oriented composite endpoint (DOCE, cardiac death, target vessel myocardial infarction and ischemia-driven target lesion revascularization [ID-TLR]). Periprocedural myocardial infarctions and periprocedural success were included among secondary endpoints.

RESULTS

One hundred six patients were included, mean age was 68.2±10.2 years and 78.3% were male. De novo diffuse CAD consisted of 52.8% long lesions and 47.2% true bifurcation lesions. Significant increase in the final minimal lumen diameters and significant decrease in the final diameter stenosis were observed when compared to the baseline values in both DES- and DCB-target segments. Procedural success was 96.2%. DOCE at one-year was 3.7%, with all the adverse events characterized by ID-TLR.

CONCLUSIONS

Combination of DES and DCB could be a safe and effective treatment option for the treatment of de novo diffuse CAD (NCT03939468).

ShOckwave ballooN or Atherectomy with Rotablation in calcified coronary artery lesions: Design and rationale of the SONAR trial

BACKGROUND

The percutaneous treatment of calcified coronary lesions remains challenging and is associated with worse clinical outcomes. In addition, coronary artery calcification is associated with more frequent peri-procedural myocardial infarction.

STUDY DESIGN AND OBJECTIVES

The ShOckwave ballooN or Atherectomy with Rotablation in calcified coronary artery lesions (SONAR) study is an investigator-initiated, prospective, randomized, international, multicenter, open label trial (NCT05208749) comparing a lesion preparation strategy with either shockwave intravascular lithotripsy (IVL) or rotational atherectomy (RA) before drug-eluting stent implantation in 170 patients with moderate to severe calcified coronary lesions. The primary endpoint is difference in the rate of peri-procedural myocardial infarction. Key secondary endpoints include rate of peri-procedural microvascular dysfunction, peri-procedural myocardial injury, descriptive study of IMR measurements in calcified lesions, technical and procedural success, interaction between OCT calcium score and primary endpoint, 30-day and 1-year major adverse clinical events.

CONCLUSIONS

The SONAR trial is the first randomized controlled trial comparing the incidence of peri-procedural myocardial infarction between 2 contemporary calcium modification strategies (Shockwave IVL and RA) in patients with calcified coronary artery lesions. Furthermore, for the first time, the incidence of peri-procedural microvascular dysfunction after Shockwave IVL and RA will be evaluated and compared.

Surface modification strategies for improved hemocompatibility of polymeric materials: a comprehensive review

Polymeric biomaterials are a widely used class of materials due to their versatile properties. However, as with all other types of materials used for biomaterials, polymers also have to interact with blood. When blood comes into contact with any foreign body, it initiates a cascade which leads to platelet activation and blood coagulation. The implant surface also has to encounter a thromboinflammatory response which makes the implant integrity vulnerable, this leads to blood coagulation on the implant and obstructs it from performing its function. Hence, the surface plays a pivotal role in the design and application of biomaterials. In particular, the surface properties of biomaterials are responsible for biocompatibility with biological systems and hemocompatibility. This review provides a report on recent advances in the field of surface modification approaches for improved hemocompatibility. We focus on the surface properties of polysaccharides, proteins, and synthetic polymers. The blood coagulation cascade has been discussed and blood - material surface interactions have also been explained. The interactions of blood proteins and cells with polymeric material surfaces have been discussed. Moreover, the benefits as well as drawbacks of blood coagulation on the implant surface for wound healing purposes have also been studied. Surface modifications implemented by other researchers to enhance as well as prevent blood coagulation have also been analyzed.

Association of Periprocedural Inflammatory Activation With Increased Risk for Early Coronary Stent Thrombosis

BACKGROUND

Stent thrombosis is a rare but deleterious event. Routine coronary angiography with percutaneous coronary intervention (PCI) is often deferred in the presence of laboratory markers of acute inflammation to prevent complications. The aim of this study was to investigate whether an acute inflammatory state is associated with an increased risk of early stent thrombosis.

METHODS AND RESULTS

Within a prospective single-center registry, the association between preprocedural acute inflammatory activation, defined as C-reactive protein plasma levels >50 mg/L or a leukocyte count >12 g/L, and occurrence of early (≤30 days) stent thrombosis was evaluated. In total, 11 327 patients underwent PCI and of those, 6880 patients had laboratory results available. 49.6% of the study population received PCI for an acute coronary syndrome and 50.4% for stable ischemic heart disease. In patients with signs of acute inflammatory activation (24.9%), PCI was associated with a significantly increased risk for stent thrombosis (hazard ratio, 2.89; P<0.00001), independent of age, sex, kidney function, number and type of stents, presence of multivessel disease, choice of P2Y12 inhibitor, and clinical presentation. Elevated laboratory markers of acute inflammation were associated with the occurrence of stent thrombosis in both patients with acute coronary syndrome (hazard ratio, 2.63; P<0.001) and in patients with stable ischemic heart disease (hazard ratio, 3.57; P<0.001).

CONCLUSIONS

An acute inflammatory state at the time of PCI was associated with a significantly increased risk of early stent thrombosis. Evidence of acute inflammation should result in deferred PCI in elective patients, while future studies are needed for patients with acute coronary syndrome.

Factors associated with early, late, and very late stent thrombosis among patients with acute coronary syndrome undergoing coronary stent placement: analysis from the ATLAS ACS 2-TIMI 51 trial

Background

Stent thrombosis (ST) is an uncommon but serious complication of stent implantation. This study aimed to explore factors associated with early, late, and very late ST to help guide risk assessment and clinical decision-making on ST.

Methods

The analysis included patients who received stent placement for the index acute coronary syndrome (ACS). Cumulative incidence of ST was assessed at 30 days (early ST), 31-360 days (late ST), 361-720 days (very late ST), and up to 720 days. Cox proportional hazards models were used to assess associations between ST and various factors, including patient characteristics [i.e., age, sex, ACS presentation, history of hypertension, smoking, diabetes, prior myocardial infarction (MI), heart failure, prior ischemic stroke, and cancer], laboratory tests [i.e., positive cardiac biomarker, hemoglobin, platelet count, white blood cell (WBC) count], and treatment [i.e., drug-eluting stent (DES) vs. bare-metal stent (BMS) and anticoagulant with rivaroxaban vs. placebo].

Results

Among the 8,741 stented patients, 155 ST events (2.25%) occurred by Day 720. The cumulative incidences of early, late, and very late ST were 0.80%, 0.81%, and 0.77%, respectively. After multivariable adjustment, age ≥ 75 [hazard ratio (HR) = 2.13 (95% confidence interval, CI: 1.26-3.60)], a history of prior MI [HR = 1.81 (95% CI: 1.22-2.68)], low hemoglobin level [HR = 2.34 (95% CI: 1.59-3.44)], and high WBC count [HR = 1.58 (95% CI: 1.02-2.46)] were associated with a greater risk of overall ST, whereas DES [HR = 0.56 (95% CI: 0.38-0.83)] and rivaroxaban therapy [HR = 0.63 (95% CI: 0.44-0.88)] were associated with a lower risk of overall ST up to 720 days. Low hemoglobin level and high WBC count were associated with early ST (low hemoglobin: HR = 2.35 [95% CI: 1.34-4.12]; high WBC count: HR = 2.11 [95% CI: 1.17-3.81]). Low hemoglobin level and prior MI were associated with a greater risk of late ST (low hemoglobin: HR = 2.32 [95% CI: 1.26-4.27]; prior MI: HR = 2.98 [95% CI: 1.67-5.31]), whereas DES was associated with a lower risk of late ST [HR = 0.33 (95% CI: 0.16-0.67)]. Age ≥75 years was associated with very late ST.

Conclusion

The study identified positive and negative associations with early, late, and very late ST. These variables may be useful in constructing risk assessment models for ST.

Clinical Trial Registration

http://www.clinicaltrials.gov, identifier NCT00809965.

Hybrid interpenetrating network of polyester coronary stent with tunable biodegradation and mechanical properties

Poly(l-lactide) (PLLA) is an important candidate raw material of the next-generation biodegradable stent for percutaneous coronary intervention, yet how to make a polyester stent with sufficient mechanical strength and relatively fast biodegradation gets to be a dilemma. Herein, we put forward a hybrid interpenetrating network (H-IPN) strategy to resolve this dilemma. As such, we synthesize a multi-functional biodegradable macromer of star-like poly(d,l-lactide-co-ɛ-caprolactone) with six acrylate end groups, and photoinitiate it, after mixing with linear PLLA homopolymer, to trigger the free radical polymerization. The resultant crosslinked polymer blend is different from the classic semi-interpenetrating network, and partial chemical crosslinking occurs between the linear polymer and the macromer network. Combined with the tube blow molding and the postprocessing laser cutting, we fabricate a semi-crosslinked-polyester biodegradable coronary stent composed of H-IPN, which includes a physical network of polyester spherulites and a chemical crosslinking network of copolyester macromers and a part of homopolymers. Compared with the currently main-stream PLLA stent in research, this H-IPN stent realizes a higher and more appropriate biodegradation rate while maintaining sufficient radial strength. A series of polymer chemistry, polymer physics, polymer processing, and in vitro and in vivo biological assessments of medical devices have been made to examine the H-IPN material. The interventional implanting of the H-IPN stent into aorta abdominalis of rabbits and the follow-ups to 12 months have confirmed the safety and effectiveness.

Early in-hospital discontinuation of aspirin on the first post-procedural day after percutaneous coronary stent implantation in patients on direct oral anticoagulation

Background

Previous trials investigating antithrombotic therapy with a direct oral anticoagulant (DOAC) and a P2Y12 inhibitor after percutaneous coronary intervention (PCI), termed dual therapy, allowed a short period of triple therapy including a DOAC, a P2Y12 inhibitor, and aspirin.

Aims

This study aimed to determine whether discontinuation of aspirin on the first post-procedural day is safe or causes ischemic events.

Methods

Ischemic and bleeding events during hospitalization were investigated retrospectively in all patients treated with dual therapy (DOAC + P2Y12 inhibitor, designated as group 1) or triple therapy (DOAC + P2Y12 inhibitor+aspirin, designated as group 2) from day 1 after PCI at our center.

Results

Of 4,564 consecutive PCI procedures, 1,059 (23.2%) had an indication for OAC. Of these, 322 met the inclusion criteria for group 1 and 62 for group 2. Baseline characteristics, CHA2DS2-VASc and HAS-BLED scores showed no relevant differences between the two groups, and the main indication for DOAC therapy was atrial fibrillation in both groups. Approximately ¼ of patients were treated for acute coronary syndrome. The mean length of post-procedural hospitalization was 2.1 ± 2.5 and 2.2 ± 3.0 days in group 1 and 2, respectively (p = 0.305). One patient per group suffered a TIA (p = 0.297). There were no other ischemic events and no statistically significant differences in bleeding events. A subgroup analysis of cases hospitalized for ≥2 post-procedural days (group 1: 100 cases, mean 4.4 ± 3.4 days vs. group 2: 25 cases, mean 4.0 ± 4.1 days) confirmed these results.

Conclusion

The initiation of dual therapy and thus discontinuation of aspirin on the first postprocedural day appears to be safe with respect to short-term ischemic events in a real-world population. Almost ¼ of patients undergoing PCI have an indication for OAC, highlighting the relevance of this issue.

Engineering Immunomodulatory Stents Using Zinc Ion-Lysozyme Nanoparticle Platform for Vascular Remodeling

Rapid endothelialization of cardiovascular materials can enhance the vascular remodeling performance. In this work, we developed a strategy for amyloid-like protein-assembly-mediated interfacial engineering to functionalize a biomimetic nanoparticle coating (BMC). Various groups (e.g., hydroxyl and carboxyl) on the BMC are responsible for chelating Zn2+ ions at the stent interface, similar to the glutathione peroxidase-like enzymes found in vivo. This design could reproduce the release of therapeutic nitric oxide gas (NO) and an aligned microenvironment nearly identical with that of natural vessels. In a rabbit abdominal aorta model, BMC-coated stents promoted vascular healing through rapid endothelialization and the inhibition of intimal hyperplasia in the placement sites at 4, 12, and 24 weeks. Additionally, better anticoagulant activity and immunomodulation in the BMC stents were also confirmed, and vascular healing was mainly dependent on cell signaling through the cyclic guanosine monophosphate-protein kinase G (cGMP-PKG) cascade. Overall, a metal-polypeptide-coated stent was developed on the basis of its detailed molecular mechanism of action in vascular remodeling.

Effects of exenatide on coronary stent's endothelialization in subjects with type 2 diabetes: a randomized controlled trial. The Rebuild study

BACKGROUND

Subjects with type 2 diabetes (T2D) have a higher risk of in-stent restenosis and stent thrombosis. The activation of the glucagon-like peptide-1 receptor (GLP-1R) has been suggested to induce several effects on the vasculature that may reduce the risk of stent failure following an angioplasty. The aim of this study is to evaluate the effect of the GLP-1R agonist exenatide on endothelialization of a modern drug-eluting stent (DES) in subjects with T2D.

METHODS

38 subjects with T2D who were eligible for revascularization with implantation of DES were randomized to treatment with exenatide (once weekly) plus standard treatment, or to standard treatment alone. After 12 weeks, a new coronary angiography was performed to evaluate the percentage of strut coverage (primary endpoint) and the presence of neo-atherosclerosis by optical coherence tomography. This study was approved by the Stockholm's Ethical Review Board.

RESULTS

The two groups were well balanced regarding baseline clinical characteristics. Strut coverage was 95% (88.7-98.5%) in the exenatide group and 91.4% (88.8-98.5%) in the control group (p = 0.692). There were no significant differences between groups neither in the thickness of neo-intima (0.2 mm in both groups, p = 0.471), nor the maximal in-stent obstruction by neo-intima (15.5% in exenatide group vs 14.7% in control group, p = 0.801). No significant differences were detected in the rate of target lesion revascularization between groups (p = 0.224).

CONCLUSION

Twelve weeks treatment with exenatide did not lead to a significantly better stent coverage in people with T2D. No significant differences in the occurrence of neo-atherosclerosis were detected between groups.

TRIAL REGISTRATION

The study was registered at www.

CLINICALTRIALS

gov (Rebuild Study, NCT02621489).

Subacute saphenous vein graft stent thrombosis due to unusual drug interaction: a case report

Background

Stent thrombosis is a potentially lethal complication of coronary angioplasty and responsible for 20% of all post-angioplasty myocardial infarctions. Unusual causes may be overlooked and difficult to identify.

Case summary

A 70-year-old male with history of triple aortocoronary bypass presented with acute inferolateral ST-segment elevation myocardial infarction (STEMI). Critical stenosis of the vein graft to the right coronary artery was revealed, and with the use of distal embolic protection device, successful angioplasty with stent was performed under double antiplatelet treatment with aspirin and ticagrelor. Two weeks later, he presented again at the emergency department with an acute inferolateral STEMI. Subacute stent thrombosis with complete occlusion of the stented vein graft was evident. Repeated balloon dilatations restored the flow stabilizing the patient; optical coherence tomography showed good stent expansion and apposition. Scrutinizing the patient's history, we discovered comedication with carbamazepine that is a CYP3A4 inducer and reduces ticagrelor's effect. Switching to prasugrel ensured potent antiplatelet treatment, and the patient was discharged 5 days later. The 6-month follow-up was uneventful and free of symptoms.

Discussion

Stent thrombosis has dire consequences, and the precipitating factors should always be investigated. Inadequate platelet inhibition secondary to non-compliance to therapy or resistance and suboptimal stent expansion/apposition are its main causes. Drug interactions are an underrecognized factor that may significantly alter the potency of antiplatelet drugs and also lead to stent thrombosis; thus, treatment is essential to be tailored to each patient comedication.

Surface Engineering of Bioactive Coatings for Improved Stent Hemocompatibility: A Comprehensive Review

Cardiovascular diseases continue to be a major contributor to illness and death on a global scale, and the implementation of stents has given rise to a revolutionary transformation in the field of interventional cardiology. The thrombotic and restenosis complications associated with stent implantation pose ongoing challenges. In recent years, bioactive coatings have emerged as a promising strategy to enhance stent hemocompatibility and reduce thrombogenicity. This review article provides an overview of the surface engineering techniques employed to improve the hemocompatibility of stents and reduce thrombus formation. It explores the mechanisms underlying thrombosis and discusses the factors influencing platelet activation and fibrin formation on stent surfaces. Various bioactive coatings, including anticoagulant agents, antiplatelet agents, and surface modifications, are discussed in detail, highlighting their potential in reducing thrombogenicity. This article also highlights a multitude of surface modification techniques which can be harnessed to enhance stent hemocompatibility including plasma treatment, physical vapor deposition (PVD), chemical vapor deposition (CVD), and electrodeposition. These techniques offer precise control over surface properties such as roughness, charge, and composition. The ultimate goal is to reduce platelet adhesion, tailor wettability, or facilitate the controlled release of bioactive agents. Evaluation methods for assessing hemocompatibility and thrombogenicity are also reviewed, ranging from in vitro assays to animal models. Recent advances in the field, such as nanotechnology-based coatings and bioactive coatings with controlled drug release systems, are highlighted. Surface engineering of bioactive coatings holds great promise for enhancing the long-term outcomes of stent implantation by enhancing hemocompatibility and reducing thrombogenicity. Future research directions and potential clinical applications are discussed, underscoring the need for continued advancements in this field.

A novel noble metal stent coating reduces in vitro platelet activation and acute in vivo thrombosis formation: a blinded study

Inherent to any stenting procedure is the prescription of dual antiplatelet therapy (DAPT) to reduce the platelet response. Clinical guidelines recommend 6-12 months of DAPT, depending on stent type, clinical picture and patient factors. Our hypothesis is that a nanostructured noble metal coating has the potential to reduce protein deposition and platelet activation. These effects would reduce subsequent thrombo-inflammatory reactions, potentially mitigating the need for an extensive DAPT in the acute phase. Here, a noble metal nanostructure coating on stents is investigated. Twelve pigs underwent endovascular implantation of coated and non-coated stents for paired comparisons in a blinded study design. The non-coated control stent was placed at the contralateral corresponding artery. Volumetric analysis of angiographic data, performed by a treatment blinded assessor, demonstrated a significant thrombus reduction for one of the coatings compared to control. This effect was already seen one hour after implantation. This finding was supported by in vitro data showing a significant reduction of coagulation activation in the coated group. This novel coating shows promise as an implant material addition and could potentially decrease the need for DAPT in the early phases of stent implementation.

Potentials of Endothelial Colony-Forming Cells: Applications in Hemostasis and Thrombosis Disorders, from Unveiling Disease Pathophysiology to Cell Therapy

Endothelial colony-forming cells (ECFCs) are endothelial progenitor cells circulating in a limited number in peripheral blood. They can give rise to mature endothelial cells (ECs) and, with intrinsically high proliferative potency, contribute to forming new blood vessels and restoring the damaged endothelium in vivo. ECFCs can be isolated from peripheral blood or umbilical cord and cultured to generate large amounts of autologous ECs in vitro. Upon differentiation in culture, ECFCs are excellent surrogates for mature ECs showing the same phenotypic, genotypic, and functional features. In the last two decades, the ECFCs from various vascular disease patients have been widely used to study the diseases' pathophysiology ex vivo and develop cell-based therapeutic approaches, including vascular regenerative therapy, tissue engineering, and gene therapy. In the current review, we will provide an updated overview of past studies, which have used ECFCs to elucidate the molecular mechanisms underlying the pathogenesis of hemostatic disorders in basic research. Additionally, we summarize preceding studies demonstrating the utility of ECFCs as cellular tools for diagnostic or therapeutic clinical applications in thrombosis and hemostasis.

The Usefulness of Intracoronary Imaging in Patients with ST-Segment Elevation Myocardial Infarction

Intracoronary imaging (ICI) modalities, namely intravascular ultrasound (IVUS) and optical coherence tomography (OCT), have shown to be able to reduce major adverse cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). Nevertheless, patients with ST-segment elevation myocardial infarction (STEMI) have been practically excluded from contemporary large randomized controlled trials. The available data are limited and derive mostly from observational studies. Nevertheless, contemporary studies are in favor of ICI utilization in patients who undergo primary PCI. Regarding technical aspects of PCI, ICI has been associated with the implantation of larger stent diameters, higher balloon inflations and lower residual in-stent stenosis post-PCI. OCT, although used significantly less often than IVUS, is a useful tool in the context of myocardial infarction without obstructive coronary artery disease since, due to its high spatial resolution, it can identify the underlying mechanism of STEMI, and, thus, guide therapy. Stent thrombosis (ST) is a rare, albeit a potential lethal, complication that is expressed clinically as STEMI in the vast majority of cases. Use of ICI is encouraged with current guidelines in order to discriminate the mechanism of ST among stent malapposition, underexpansion, uncovered stent struts, edge dissections, ruptured neoatherosclerotic lesions and coronary evaginations. Finally, ICI has been proposed as a tool to facilitate stent deferring during primary PCI based on culprit lesion characteristics.

A novel biodegradable polymer-coated sirolimus-eluting stent: 1-year results of the HELIOS registry

BACKGROUND

The HELIOS stent is a sirolimus-eluting stent with a biodegradable polymer and titanium oxide film as the tie-layer. The study aimed to evaluate the safety and efficacy of HELIOS stent in a real-world setting.

METHODS

The HELIOS registry is a prospective, multicenter, cohort study conducted at 38 centers across China between November 2018 and December 2019. A total of 3060 consecutive patients were enrolled after application of minimal inclusion and exclusion criteria. The primary endpoint was target lesion failure (TLF), defined as a composite of cardiac death, non-fatal target vessel myocardial infarction (MI), and clinically indicated target lesion revascularization (TLR) at 1-year follow-up. Kaplan-Meier methods were used to estimate the cumulative incidence of clinical events and construct survival curves.

RESULTS

A total of 2998 (98.0%) patients completed the 1-year follow-up. The 1-year incidence of TLF was 3.10% (94/2998, 95% closed interval: 2.54-3.78%). The rates of cardiac death, non-fatal target vessel MI and clinically indicated TLR were 2.33% (70/2998), 0.20% (6/2998), and 0.70% (21/2998), respectively. The rate of stent thrombosis was 0.33% (10/2998). Age ≥60 years, diabetes mellitus, family history of coronary artery disease, acute myocardial infarction at admission, and device success were independent predictors of TLF at 1 year.

CONCLUSION

The 1-year incidence rates of TLF and stent thrombosis were 3.10% and 0.33%, respectively, in patients treated with HELIOS stents. Our results provide clinical evidence for interventional cardiologists and policymakers to evaluate HELIOS stent.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT03916432.

Computational Fluid Dynamics for the Prediction of Endograft Thrombosis in the Superficial Femoral Artery

Purpose:

Contemporary diagnostic modalities, including contrast-enhanced computed tomography (CTA) and duplex ultrasound, have been insufficiently able to predict endograft thrombosis. This study introduces an implementation of image-based computational fluid dynamics (CFD), by exemplification with 4 patients treated with an endograft for occlusive disease of the superficial femoral artery (SFA). The potential of personalized CFD for predicting endograft thrombosis is investigated.

Materials and Methods:

Four patients treated with endografts for an occluded SFA were retrospectively included. CFD simulations, based on CTA and duplex ultrasound, were compared for patients with and without endograft thrombosis to investigate potential flow-related causes of endograft thrombosis. Time-averaged wall shear stress (TAWSS) was computed, which highlights areas of prolonged residence times of coagulation factors in the graft.

Results:

CFD simulations demonstrated normal TAWSS (>0.4 Pa) in the SFA for cases 1 and 2, but low levels of TAWSS (<0.4 Pa) in cases 3 and 4, respectively. Primary patency was achieved in cases 1 and 2 for over 2 year follow-up. Cases 3 and 4 were complicated by recurrent endograft thrombosis.

Conclusion:

The presence of a low TAWSS was associated with recurrent endograft thrombosis in subjects with otherwise normal anatomic and ultrasound assessment and a good distal run-off.

The biology of SCUBE

The SCUBE [Signal peptide-Complement C1r/C1s, Uegf, Bmp1 (CUB)-Epithelial growth factor domain-containing protein] family consists of three proteins in vertebrates, SCUBE1, 2 and 3, which are highly conserved in zebrafish, mice and humans. Each SCUBE gene encodes a polypeptide of approximately 1000 amino acids that is organized into five modular domains: (1) an N-terminal signal peptide sequence, (2) nine tandem epidermal growth factor (EGF)-like repeats, (3) a large spacer region, (4) three cysteine-rich (CR) motifs, and (5) a CUB domain at the C-terminus. Murine Scube genes are expressed individually or in combination during the development of various tissues, including those in the central nervous system and the axial skeleton. The cDNAs of human SCUBE orthologs were originally cloned from vascular endothelial cells, but SCUBE expression has also been found in platelets, mammary ductal epithelium and osteoblasts. Both soluble and membrane-associated SCUBEs have been shown to play important roles in physiology and pathology. For instance, upregulation of SCUBEs has been reported in acute myeloid leukemia, breast cancer and lung cancer. In addition, soluble SCUBE1 is released from activated platelets and can be used as a clinical biomarker for acute coronary syndrome and ischemic stroke. Soluble SCUBE2 enhances distal signaling by facilitating the secretion of dual-lipidated hedgehog from nearby ligand-producing cells in a paracrine manner. Interestingly, the spacer regions and CR motifs can increase or enable SCUBE binding to cell surfaces via electrostatic or glycan-lectin interactions. As such, membrane-associated SCUBEs can function as coreceptors that enhance the signaling activity of various serine/threonine kinase or tyrosine kinase receptors. For example, membrane-associated SCUBE3 functions as a coreceptor that promotes signaling in bone morphogenesis. In humans, SCUBE3 mutations are linked to abnormalities in growth and differentiation of both bones and teeth. In addition to studies on human SCUBE function, experimental results from genetically modified mouse models have yielded important insights in the field of systems biology. In this review, we highlight novel molecular discoveries and critical directions for future research on SCUBE proteins in the context of cancer, skeletal disease and cardiovascular disease.

The contemporary role of protamine in the cardiac catheterization laboratory

Access to the arterial circulation and full anticoagulation carries a risk of serious bleeding during and after percutaneous coronary intervention. Important sources of bleeding include the arterial access site and coronary artery perforation. Prompt and effective management of hemorrhagic complications is an essential interventional skill. Protamine sulfate is well-known as a heparin reversal agent. Despite this, there is heterogeneity in the use of protamine during interventional procedures. While protamine is generally well-tolerated, it is associated with a risk of hypersensitivity reaction, including anaphylaxis, among others. The purpose of this review is to summarize the existing evidence about and experience with the use of protamine sulfate in the setting of percutaneous coronary and structural interventional procedures.

Antiplatelet Strategies Following PCI: A Review of Trials Informing Current and Future Therapies

Dual antiplatelet therapy (DAPT) has been paramount in preventing thrombosis following percutaneous coronary intervention for nearly 3 decades. However, over the years, DAPT has seen significant changes in the agents utilized and duration of therapy as trials have raced to keep up with advancements made in stent technology and our understanding of bleeding and ischemic risk. Recently, there have been a number of trials demonstrating significant reductions in bleeding events with shorter DAPT durations, which are not yet reflected in practice guidelines. Further, there has been a shift toward more individualized antiplatelet regimens to meet patient-specific risk profiles. This review provides a comprehensive summary of the major trials that have informed current DAPT strategies, puts into context recent trials driving a shift toward more tailored antiplatelet regimens, and highlights gaps in knowledge that remain and the ongoing trials designed to address them.

Fifteen-Year Nationwide Trend in Antiplatelet Treatment among Drug-Eluting Stent Recipients in Korea: Many Patients Receive Very Prolonged Dual-Antiplatelet Treatment, and Newer Drugs Are Replacing the Older Ones

Drug-eluting stent (DES) recipients require 6–12 months of dual antiplatelet treatment (DAPT) and long-term aspirin mono-antiplatelet treatment (MAPT). Given the diversity of contemporary antiplatelet agents, antiplatelet treatment (APT) selection is becoming more complicated. We evaluated 15-year APT trends based on nationwide prescription data of 79,654 patients who underwent percutaneous coronary intervention (PCI) using DESs from 2002 to 2018 in Korea. DAPT (80.7%) was the most preferred initial APT post-PCI. Many DES recipients received prolonged DAPT (post-PCI 3 years: 41.0%; 10 years: 27.7%). There was a noticeable delay in DAPT-to-MAPT conversion from the mid to late 2000s (after the late-stent thrombosis concerns of first-generation DESs raised); the conversion after that was similar during the 2010s, occurring most robustly at 12–18 months post-PCI. Clopidogrel had long and increasingly been used for MAPT, surpassing aspirin. The recent increase in newer P2Y12 inhibitor prescriptions was noted. The patients treated with newer P2Y12 inhibitors were more likely younger men and presented with acute myocardial infarction. Real-world APT is evolving, and guideline–practice gaps exist. Further studies exploring the impact of diverse APT strategies on patient outcomes are expected to provide insights into optimal APT that can sophisticatedly balance the ischemic and bleeding risks.

Management of failed stenting of the unprotected left main coronary artery

Percutaneous coronary intervention (PCI) is increasingly accepted as treatment for unprotected left main coronary artery (ULMCA) disease especially in those patients who are unsuitable for cardiac surgery. Treatment of any stent failure is associated with increased complexity and worse clinical outcomes when compared with de novo lesion revascularization. Intracoronary imaging has provided new insight into mechanisms of stent failure and treatment options have developed considerably over the last decade. There is paucity of evidence on the management strategy for stent failure in the specific setting of ULMCA. Treating any left main with PCI requires careful consideration and consequently treatment of failed stents in ULMCA is complex and provides unique challenges. Consequently, we provide an overview of ULMCA stent failure, proposing a tailored algorithm to guide best management and decision in daily clinical practice, with a special focus on intracoronary imaging characterization of causal mechanisms and specific technical and procedural considerations.

A Case of Subacute Stent Thrombosis

A 67-year-old male presenting with an anterior ST-segment elevation myocardial infarction (STEMI) underwent stent placement in the left anterior descending coronary. The patient was discharged on an appropriate medical regimen containing dual antiplatelet therapy (DAPT). Four days later, the patient presented with repeat acute coronary syndrome symptomatology. Electrocardiogram demonstrated ongoing STEMI in the previously treated artery distribution. Emergency angiography revealed restenosis and total thrombotic occlusion. Post-intervention stenosis was 0% after aspiration thrombectomy and balloon angioplasty. Stent thrombosis is a high-mortality and therapeutically challenging condition requiring prepared clinicians who recognize predisposing risk factors and initiate early management.

Stent Thrombosis and Restenosis with Contemporary Drug-Eluting Stents: Predictors and Current Evidence

Iterations in stent technologies, advances in pharmacotherapy, and awareness of the implications of implantation techniques have markedly reduced the risk of stent failure, both in the form of stent thrombosis (ST) and in-stent restenosis (ISR). However, given the number of percutaneous coronary interventions (PCI) performed worldwide every year, ST and ISR, albeit occurring at a fairly low rate, represent a public health problem even with contemporary DES platforms. The understanding of mechanisms and risk factors for these two PCI complications has been of fundamental importance for the parallel evolution of stent technologies. Risk factors associated with ST and ISR are usually divided into patient-, lesion-, device- and procedure-related. A number of studies have shown how certain risk factors are related to early (1 month) versus late/very late ST (between 1 month and 1 year and >1 year, respectively). However, more research is required to conclusively show the role of time-dependence of risk factors also in the incidence of ISR (early [1 year] or late [>1 year]). A thorough risk assessment is required due to the complex etiology of ST and ISR. The most effective strategy to treat ST and ISR is still to prevent them; hence, it is crucial to identify patient-, lesion-, device- and procedure-related predictors.

Caplacizumab for treating subacute intra-stent thrombus occurring despite efficacious double anti-platelet treatment and anticoagulation: a case report

Background

Acute and subacute stent thromboses are a rare complication associated with high mortality and morbidity occurring in ∼1.5% of patients treated with primary percutaneous intervention for ST-elevation myocardial infarction (STEMI). Recent publications describe a potential role of the von Willebrand factor (VWF) in thrombus formation at sites of critical coronary stenosis in STEMI.

Case summary

We describe a 58-year-old woman with STEMI at initial presentation, who suffered subacute stent thrombosis despite good stent expansion, efficacious dual antiplatelet therapy, and therapeutic anticoagulation. Because of very high VWF values, we administered N-acetylcysteine in order to depolymerize VWF, but the drug was not well tolerated. Since the patient was still symptomatic, we used caplacizumab in order to prevent VWF from interacting with platelets. Under this treatment, the clinical and angiographic course was favourable.

Discussion

Considering a modern view of intracoronary thrombus pathophysiology, we describe an innovative treatment approach, which eventually ended in a favourable outcome.

Early vascular healing after neXt-generation drug-eluting stent implantation in Patients with non-ST Elevation acute Coronary syndrome based on optical coherence Tomography guidance and evaluation (EXPECT): study protocol for a randomized controlled trial

Background

There is limited evidence about vessel wall healing response following implantation of next-generation drug-eluting stents (DES) in patients admitted with a non-ST elevation acute coronary syndrome (NSTE-ACS). Cumulative data indicate that optical coherence tomography (OCT) imaging can optimize percutaneous coronary intervention results and expedite stent endothelialization in the general population but there is lack of data in NSTE-ACS patients.

Methods

The EXPECT study is an investigator-initiated, prospective, randomized trial to assess early vascular healing response following next-generation DES implantation in patients admitted with NSTE-ACS based on OCT guidance and evaluation. Sixty patients are randomized at 1:1:1 ratio to OCT-guided percutaneous coronary intervention (PCI) with 3-month follow-up OCT imaging (O3 group, n = 20), to angiography-guided PCI with 3-month follow-up OCT imaging (A3 group, n = 20) and to angiography-guided PCI with 6-month follow-up OCT imaging (A6 group, n = 20). The primary endpoint of the study is stent strut coverage rate at 3- or 6- month follow-up in the studied groups. The secondary endpoints of the study include OCT imaging endpoints, clinical endpoints, and molecular biology endpoints at the different time points. The clinical endpoints comprised of major cardiovascular adverse events and individual components. The molecular biology endpoints comprised of lipid levels and the levels of inflammatory indicators.

Discussion

The findings of the EXPECT study are anticipated to provide novel insights into vessel wall healing in NSTE-ACS population following implantation of next-generation DES, underscore the value of OCT imaging in expediting strut coverage in this setting, and explore the potential of an early discontinuation of dual antiplatelet therapy (DAPT) in this population.

Clinical Trial Registration

ClinicalTrials.gov, NCT04375319.

A non-linear relationship between lesion length and risk of recurrent cerebral ischemia after stenting for symptomatic intracranial stenosis with hemodynamic impairment

Background

Stent placement can be an effective treatment for patients with symptomatic intracranial stenosis (sICAS) and hemodynamic impairment (HI). However, the association between lesion length and the risk of recurrent cerebral ischemia (RCI) after stenting remains controversial. Exploring this association can help predict patients at higher risk for RCI and develop individualized follow-up schedules.

Method

In this study, we provided a post-hoc analysis of a prospective, multicenter registry study on stenting for sICAS with HI in China. Demographics, vascular risk factors, clinical variables, lesions, and procedure-specific variables were recorded. RCI includes ischemic stroke and transient ischemic attack (TIA), from month 1 after stenting to the end of the follow-up period. Smoothing curve fitting and segmented Cox regression analysis were used to analyze the threshold effect between lesion length and RCI in the overall group and subgroups of the stent type.

Results

The non-linear relationship between lesion length and RCI was observed in the overall population and subgroups; however, the non-linear relationship differed by subgroup of stent type. In the balloon-expandable stent (BES) subgroup, the risk of RCI increased 2.17-fold and 3.17-fold for each 1-mm increase in the lesion length when the lesion length was <7.70 mm and >9.00 mm, respectively. In the self-expanding stent (SES) subgroup, the risk of RCI increased 1.83-fold for each 1-mm increase in the lesion length when the length was <9.00 mm. Nevertheless, the risk of RCI did not increase with the length when the lesion length was >9.00mm.

Conclusion

A non-linear relationship exists between lesion length and RCI after stenting for sICAS with HI. The lesion length increases the overall risk of RCI for BES and for SES when the length was <9.00 mm, while no significant relationship was found when the length was >9.00 mm for SES.

Resistance on the Latest Oral and Intravenous P2Y12 ADP Receptor Blockers in Patients with Acute Coronary Syndromes: Fact or Myth?

Novel P2Y12 ADP receptor blockers (ADPRB) should be preferred in dual-antiplatelet therapy in patients with acute coronary syndrome. Nevertheless, there are still patients who do not respond optimally to novel ADP receptor blocker therapy, and this nonoptimal response (so-called "high on-treatment platelet reactivity" or "resistance") could be connected with increased risk of adverse ischemic events, such as myocardial re-infarction, target lesion failure and stent thrombosis. In addition, several risk factors have been proposed as factors associated with the phenomenon of inadequate response on novel ADPRB. These include obesity, multivessel coronary artery disease, high pre-treatment platelet reactivity and impaired metabolic status for prasugrel, as well as elderly, concomitant therapy with beta-blockers, morphine and platelet count for ticagrelor. There is no literature report describing nonoptimal therapeutic response on cangrelor, and cangrelor therapy seems to be a possible approach for overcoming HTPR on prasugrel and ticagrelor. However, the optimal therapeutic management of "resistance" on novel ADPRB is not clear and this issue requires further research. This narrative review article discusses the phenomenon of high on-treatment platelet reactivity on novel ADPRB, its importance in clinical practice and approaches for its therapeutic overcoming.

Computational simulation of stent thrombosis induced by various degrees of stent malapposition

Percutaneous coronary intervention with stent implantation is one of the most commonly used approaches to treat coronary artery stenosis. Stent malapposition (SM) can increase the incidence of stent thrombosis, but the quantitative association between SM distance and stent thrombosis is poorly clarified. The objective of this study is to determine the biomechanical reaction mechanisms underlying stent thrombosis induced by SM and to quantify the effect of different SM severity grades on thrombosis. The thrombus simulation was performed in a continuous model based on the diffusion-convection response of blood substance transport. Simulated models included well-apposed stents and malapposed stents with various severities where the detachment distances ranged from 0 to 400 μm. The abnormal shear stress induced by SM was considered a critical contributor affecting stent thrombosis, which was dependent on changing SM distances in the simulation. The results illustrate that the proportion of thrombus volume was 1.88% at a SM distance of 75 μm (mild), 3.46% at 150 μm, and 3.93% at 400 μm (severe), but that a slight drop (3.18%) appeared at the detachment distance of 225 μm (intermediate). The results indicate that when the SM distance was less than 150 μm, the thrombus rose notably as the gap distance increased, whereas the progression of thrombogenicity weakened when it exceeded 150 μm. Therefore, more attention should be paid when SM is present at a gap distance of 150 μm. Moreover, when the SM length of stents are the same, thrombus tends to accumulate downstream towards the distal end of the stent as the SM distance increases.

Inhibition of mitochondrial complex I leading to NAD+/NADH imbalance in type 2 diabetic patients who developed late stent thrombosis: Evidence from an integrative analysis of platelet bioenergetics and metabolomics

Type 2 diabetes mellitus (T2DM) is a strong indicator of late stent thrombosis (LST). Platelet bioenergetic dysfunction, although critical to the pathogenesis of diabetic macrovascular complications, remains uncharacterized in T2DM patients who developed LST. Here, we explored the mechanistic link between the alterations in platelet bioenergetics and LST in the setting of T2DM. Platelet bioenergetics, metabolomics, and their interactomes were analyzed in a nested case-control study including 15 T2DM patients who developed LST and 15 matched T2DM patients who did not develop LST (non-LST). Overall, we identified a bioenergetic alteration in T2DM patients with LST characterized by an imbalanced NAD+/NADH redox state resulting from deficient mitochondrial complex I (NADH: ubiquinone oxidoreductase) activity, which led to reduced ATP-linked and maximal mitochondrial respiration, increased glycolytic flux, and platelet hyperactivation compared with non-LST patients. Congruently, platelets from LST patients exhibited downregulation of tricarboxylic acid cycle and NAD+ biosynthetic pathways as well as upregulation of the proximal glycolytic pathway, a metabolomic change that was primarily attributed to compromised mitochondrial respiration rather than increased glycolytic flux as evidenced by the integrative analysis of bioenergetics and metabolomics. Importantly, both bioenergetic and metabolomic aberrancies in LST platelets could be recapitulated ex vivo by exposing the non-LST platelets to a low dose of rotenone, a complex I inhibitor. In contrast, normalization of the NAD+/NADH redox state, either by increasing NAD+ biosynthesis or by inhibiting NAD+ consumption, was able to improve mitochondrial respiration, inhibit mitochondrial oxidant generation, and consequently attenuate platelet aggregation in both LST platelets and non-LST platelets pretreated with low-dose rotenone. These data, for the first time, delineate the specific patterns of bioenergetic and metabolomic alterations for T2DM patients who suffer from LST, and establish the deficiency of complex I-derived NAD+ as a potential pathogenic mechanism in platelet abnormalities.

Biofunctionalization of cardiovascular stents to induce endothelialization: Implications for in- stent thrombosis in diabetes

Stent thrombosis remains one of the main causes that lead to vascular stent failure in patients undergoing percutaneous coronary intervention (PCI). Type 2 diabetes mellitus is accompanied by endothelial dysfunction and platelet hyperactivity and is associated with suboptimal outcomes following PCI, and an increase in the incidence of late stent thrombosis. Evidence suggests that late stent thrombosis is caused by the delayed and impaired endothelialization of the lumen of the stent. The endothelium has a key role in modulating inflammation and thrombosis and maintaining homeostasis, thus restoring a functional endothelial cell layer is an important target for the prevention of stent thrombosis. Modifications using specific molecules to induce endothelial cell adhesion, proliferation and function can improve stents endothelialization and prevent thrombosis. Blood endothelial progenitor cells (EPCs) represent a potential cell source for the in situ-endothelialization of vascular conduits and stents. We aim in this review to summarize the main biofunctionalization strategies to induce the in-situ endothelialization of coronary artery stents using circulating endothelial stem cells.

Stent Thrombosis After Percutaneous Coronary Intervention: From Bare-Metal to the Last Generation of Drug-Eluting Stents

Since their introduction in clinical practice in 1986, different types of coronary stents have been developed and become available for the treatment of coronary artery disease. Stent thrombosis (ST) is an uncommon but harmful complication after percutaneous coronary implantation, with a high occurrence of acute myocardial infarction and risk of mortality. Among several procedural and clinical predictors, the type of coronary stent is a strong determinant of ST. This article reviews the available evidence on the most used coronary stent types in the modern era and the related risk of ST.

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.

Acute Intraprocedural Thrombosis After Flow Diverter Stent Implantation: Risk Factors and Relevance of Standard Observation Time for Early Detection and Management

PURPOSE

Acute intraprocedural thrombosis (AIT) is a severe complication of flow diverter stent (FDS) implantation for the treatment of intracranial aneurysms. Even though device-related thromboembolic complications are well known, there are no acknowledged risk factors nor defined surveillance protocols for their early detection. This study aimed to demonstrate that an angiographic active surveillance is effective to detect and treat AIT. Furthermore, we investigated risk factors for the occurrence of AIT.

METHODS

A prospective institutional protocol consisting of a defined observation period of 30 min following FDS deployment was established to detect AIT. Overall incidence, as well as the efficacy and safety of AIT treatment were assessed. Moreover, radiological and clinical outcomes of patients with AIT were analyzed. The influence of various patient- and procedure-related factors on the occurrence of AIT was investigated using multivariable forward logistic regression.

RESULTS

During active surveillance twelve cases of AIT were observed among a total of 161 procedures (incidence: 7.5%). The median time of first observation was 15.5 min (IQR 9.5) after FDS implantation. The early recognition of AIT ensured a prompt treatment with intravenous application of a glycoprotein IIb/IIIa inhibitor, which led to complete thrombus resolution in all cases without hemorrhagic complications. Patients with pre-existing arterial hypertension and side branches originating from the aneurysmal sac had a higher risk of AIT (respectively OR, 9.844; OR, 3.553). There were two cases of re-thrombosis in the short-term postoperative period, of whom one died. The remaining patients with AIT had a good clinical outcome.

CONCLUSION

Active surveillance for 30 min after FDS implantation is an effective strategy for early detection and ensuing treatment of AIT and can thus prevent secondary sequalae. Hypertension and side branches originating from the aneurysmal sac may increase the risk of AIT.

How to deal with vessel diameter mismatch in left main bifurcation stenting

Left main coronary artery percutaneous coronary intervention is particularly complex when stenting across the distal bifurcation is required in the presence of a diameter mismatch between the proximal main and distal branches. A suboptimal procedural result increases the risk of thrombosis and restenosis. Considering the paucity of data published on this topic, our objective was to provide technical solutions to deal with this complex anatomy. We described four cases showing the use of devices and techniques which allowed us to overcome a diameter discrepancy between adjacent coronary segments: (1) self-expanding nitinol stent; (2) stent platform with noteworthy expansion capacity; (3) the 'extended skirt' technique; (4) the 'trouser-leg' technique. In conclusion, the use of specific strategies and devices allows a safe and effective approach to be used to perform treatment that respects the coronary anatomy, and to optimize percutaneous coronary intervention results in complex scenarios.

Clinical outcomes of no stenting in patients with ST-segment elevation myocardial infarction undergoing deferred primary percutaneous coronary intervention

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) is treated with stenting, but the underlying stenosis is often not severe, and stenting may potentially be omitted.

AIMS

The aim of the study was to investigate outcomes of patients with STEMI treated with percutaneous coronary intervention (PCI) without stenting.

METHODS

Patients were identified through the DANAMI-3-DEFER study. Stenting was omitted in the patients with stable flow after initial PCI and no significant residual stenosis on the deferral procedure, who were randomised to deferred stenting. These patients were compared to patients randomised to conventional PCI treated with immediate stenting. The primary endpoint was a composite of all-cause mortality, recurrent myocardial infarction (MI), and target vessel revascularisation (TVR).

RESULTS

Of 603 patients randomised to deferred stenting, 84 were treated without stenting, and in patients randomised to conventional PCI (n=612), 590 were treated with immediate stenting. Patients treated with no stenting had a median stenosis of 40%, median vessel diameter of 2.9 mm, and median lesion length of 11.4 mm. During a median follow-up of 3.4 years, the composite endpoint occurred in 14% and 16% in the no and immediate stenting groups, respectively (unadjusted hazard ratio [HR] 0.87, 95% confidence interval [CI]: 0.48-1.60; p=0.66). The association remained non-significant after adjusting for confounders (adjusted HR 0.53, 95% CI: 0.22-1.24; p=0.14). The rates of TVR and recurrent MI were 2% vs 4% (p=0.70) and 4% vs 6% (p=0.43), respectively.

CONCLUSIONS

Patients with STEMI, with no significant residual stenosis and stable flow after initial PCI, treated without stenting, had comparable event rates to patients treated with immediate stenting.

Independent Clinical Impacts of Procedural Complexity on Ischemic and Bleeding Events in Patients with Acute Myocardial Infarction: Long-Term Clinical Study

This study aimed to investigate the relationship between a complex percutaneous coronary intervention (C-PCI) and long-term clinical outcomes in the AMI cohort. A total of 10,329 patients were categorized into the C-PCI and non-C-PCI groups. The primary ischemic endpoint was a composite of major adverse cardiac events (MACEs, cardiac death, myocardial infarction, stent thrombosis and revascularization). The primary bleeding endpoint was the risk of overt bleeding (BARC 2, 3 or 5). The median follow-up duration was 4.9 (2.97, 7.16) years. The risks of MACEs and bleeding were significantly higher in the C-PCI group (hazard ratio (HR): 1.72; 95% confidence interval (CI): 1.60 to 1.85; p < 0.001; and HR: 1.32; 95% CI: 1.17 to 1.50; p < 0.001, respectively). After propensity score matching, compared to the non-C-PCI group, the adjusted MACE rate in C-PCI remained significantly higher (p < 0.001), but no significant interaction (p = 0.273) was observed for bleeding. Significant differences in overt bleeding were observed only within the first three months (p = 0.024). The MACEs were consistently higher in the C-PCI group with or without severe comorbid conditions (p < 0.001 for both). Patients with AMI who undergo C-PCI experience worse long-term ischemic outcomes after successful PCI, regardless of the presence of severe comorbidities.