Long-term clinical and angiographic follow-up after coronary stent placement in native coronary arteries

Naturally Occurring Atherosclerosis Progression and In-stent Restenosis: Exploring Histomorphologic Associations Using Optical Coherence Tomography

ABSTRACT

The mechanism of in-stent restenosis (ISR) remains elusive, and in-stent neoatherosclerosis (ISNA) may hold significant pathophysiologic implications. Nevertheless, the correlation between ISNA and the progression of untreated coronary segments affected by native atherosclerosis remains incompletely investigated. This study enrolled 225 patients diagnosed with coronary heart disease and multivessel disease. These patients underwent successful percutaneous coronary intervention and intraoperative placement of the drug-eluting stent, followed by optical coherence tomography assessment of the culprit stent. The mechanism of ISR was examined through qualitative and quantitative analysis of optical coherence tomography imaging. A significantly higher proportion of patients in the ISR with nontarget lesion progression (N-TLP) group exhibited lipid plaque formation compared with the ISR without N-TLP group (69.0% vs. 39.8%, P < 0.001). The incidence of thin-cap fibroatheroma (33.3% vs. 11.4%, P = 0.001) and ISNA (60.7% vs. 38.6%, P < 0.001) was markedly elevated in the ISR with N-TLP group compared with the ISR without N-TLP group. Regarding manifestations, heterogeneous hyperplasia was predominantly observed in the ISR with N-TLP group (76.2% vs. 38.6%, P < 0.001), whereas homogeneous hyperplasia was primarily presented in the ISR without N-TLP group (61.4% vs. 23.8%, P < 0.001). Patients displaying notable progression of naturally occurring atherosclerosis manifest histomorphologic features of ISR, primarily characterized by heterogeneous intimal hyperplasia and a higher prevalence of ISNA. In contrast, patients without substantial progression of naturally occurring atherosclerosis exhibit histomorphologic features of ISR primarily characterized by homogeneous intimal hyperplasia.

Updates in the Management of Coronary Artery Disease: A Review Article

Coronary artery disease (CAD) remains a significant health challenge, imposing substantial burdens on individuals and healthcare systems worldwide. CAD's impact stems from artery narrowing and blockage, leading to severe complications like heart attacks and heart failure. Collaborative efforts by researchers, professionals, and governments have fostered advancements in comprehending and managing this cardiovascular ailment. Evolving CAD management embraces modern diagnostics, cutting-edge pharmaceuticals, invasive procedures, lifestyle modifications, and cardiac rehabilitation. This comprehensive approach aims to amplify outcomes and elevate the quality of life for CAD-affected individuals. This review delves into innovative treatments, pivotal breakthroughs, and recent trends in clinical practices that collectively shape CAD management. The exploration encompasses novel diagnostic technologies enabling early detection and risk assessment. Moreover, it investigates recent breakthroughs in medications that profoundly impact platelet disorders, lipid reduction, and angina. Precision medicine's role in tailoring treatment strategies based on patient characteristics is thoroughly examined. Advances in invasive procedures, like percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), have revolutionised coronary revascularisation, substantially improved long-term outcomes, and reduced restenosis rates. The increasing significance of lifestyle changes and cardiac rehabilitation in CAD management, augmenting treatment options and patient recovery, are meticulously scrutinized. While these strides are pivotal, research continues to chart new paths in CAD management, from innovative drugs to collaborative multidisciplinary care models. Staying attuned to the latest advancements and embracing a patient-centric approach can collectively reduce CAD's impact and facilitate the lives of those grappling with this chronic cardiovascular disorder.

Postintervention monitoring of peripheral arterial disease wound healing using dynamic vascular optical spectroscopy

SIGNIFICANCE

Due to the persistence of chronic wounds, a second surgical intervention is often necessary for patients with peripheral arterial disease (PAD) within a year of the first intervention. The dynamic vascular optical spectroscopy system (DVOS) may assist physicians in determining patient prognosis only a month after the first surgical intervention.

AIM

We aim to assess the DVOS utility in characterizing wound healing in PAD patients after endovascular intervention.

APPROACH

The DVOS used near-infrared light ( 670 < λ < 850    nm ) to record hemodynamic response to a cuff inflation in 14 PAD patients with lower limb ulcers immediately before, immediately after, and at a first follow-up 3 to 4 weeks after intervention. Ankle-brachial index (ABI) and arterial duplex ultrasound (A-DUS) measurements were obtained when possible.

RESULTS

The total hemoglobin plateau time differed significantly between patients with ulcers that reduced in size ( N = 9 ) and patients with ulcers that did not ( N = 5 ) 3 to 4 weeks after intervention ( p  value < 0.001 ). Data correlated strongly (89% sensitivity, 100% specificity, and AUC = 0.96 ) with long-term wound healing. ABI and A-DUS measurements were not statistically associated with wound healing.

CONCLUSIONS

This pilot study demonstrates the potential of the DVOS to aid physicians in giving accurate long-term wound healing prognoses 1 month after intervention.

Hemodynamic and Geometric Risk Factors for In-Stent Restenosis in Patients with Intracranial Atherosclerotic Stenosis

Methods

Severe ICAS patients managed with percutaneous transluminal angioplasty and stenting (PTAS) were included in the retrospective cohort study and were divided into two groups according to whether ISR occurred at follow-up (ISR group and no-ISR group). Computational fluid dynamics models were built based on digital subtraction angiography before and after PTAS to simulate blood flow and quantify hemodynamic parameters. The associations between vessel geometry, hemodynamics, and ISR in ICAS patients were investigated.

Results

Among 39 patients, ISR occurred in seven patients (17.95%) after a mean follow-up period of 6.69 ± 3.24 months. Stenting decreased vessel angulation (51.11° [40.07°-67.27°] vs. 15.97° [0.00°-36.16°], P = 0.000) and vessel tortuosity (0.09 [0.06-0.13] vs. 0.01 [0.00-0.03], P = 0.000). Meanwhile, the translational pressure ratio (PR) dramatically increased (0.07 [0.00-0.31] vs. 0.62 [0.41-0.82], P = 0.000) with the wall shear stress ratio decreased (13.93 [8.37-40.30] vs. 2.90 [1.69-4.48], P = 0.000). In the multivariate analysis, smaller Δ tortuosity (P = 0.038) was independently associated with the occurrence of ISR, and smaller post-PTAS translesional PR was also a predictive factor of marginal significance (P = 0.059).

Conclusion

PTAS decreased vessel angulation, vessel tortuosity, and translesional wall shear stress ratio while it increased translesional pressure ratio (PR) dramatically in ICAS patients. Smaller Δ tortuosity was found to be a risk factor for ISR, and smaller post-PTAS translesional PR was also a predictive factor of marginal significance, indicating that both geometric and hemodynamic parameters played important roles in the occurrence of ISR after PTAS.

Advantages and prospects of optical coherence tomography in interventional therapy of coronary heart disease (Review)

Coronary heart disease is the leading cause of mortality among all diseases globally. Percutaneous coronary intervention (PCI) is a key method for the treatment of coronary heart disease. Optical coherence tomography (OCT) is an optical diagnostic technology with a resolution of up to 10 µm, which is able to accurately assess the composition of the coronary arterial wall and determine the characteristics of atherosclerotic lesions. It is also highly consistent with pathological examinations, optimizing the effect of stent implantation and evaluation of the long-term effectiveness and safety of the stent, which has irreplaceable value in the field of precision and optimization of coronary intervention. The innovative OCT technology may help provide more comprehensive clinical research evidence. The application of OCT in clinical and basic research of coronary atherosclerosis, selection of treatment strategies for acute coronary syndromes, optimization of interventional treatment efficacy, evaluation of novel stents, intimal stent coverage and selection of dual antiplatelet drugs has become more widely used, affecting the current coronary interventional treatment strategies to a certain extent. The aim of the present review was to discuss the role of OCT in evaluating preoperative plaque characteristics, guiding PCI and evaluating the effects of postoperative stents or drug treatments.

In Stent Neo-Atherosclerosis: Pathophysiology, Clinical Implications, Prevention, and Therapeutic Approaches

Despite the dramatic improvements of revascularization therapies occurring in the past decades, a relevant percentage of patients treated with percutaneous coronary intervention (PCI) still develops stent failure due to neo-atherosclerosis (NA). This histopathological phenomenon following stent implantation represents the substrate for late in-stent restenosis (ISR) and late stent thrombosis (ST), with a significant impact on patient’s long-term clinical outcomes. This appears even more remarkable in the setting of drug-eluting stent implantation, where the substantial delay in vascular healing because of the released anti-proliferative agents might increase the occurrence of this complication. Since the underlying pathophysiological mechanisms of NA diverge from native atherosclerosis and early ISR, intra-coronary imaging techniques are crucial for its early detection, providing a proper in vivo assessment of both neo-intimal plaque composition and peri-strut structures. Furthermore, different strategies for NA prevention and treatment have been proposed, including tailored pharmacological therapies as well as specific invasive tools. Considering the increasing population undergoing PCI with drug-eluting stents (DES), this review aims to provide an updated overview of the most recent evidence regarding NA, discussing pathophysiology, contemporary intravascular imaging techniques, and well-established and experimental invasive and pharmacological treatment strategies.

Long term outcomes after bare metal stent implantation

Long term outcome data after BMS implant is not available from the Indian subcontinent. This is a prospective observational study which aims to study long term outcomes after BMS implant at a tertiary care centre. 100 consecutive patients underwent BMS implant and were followed up for 20 years. LAD was the most common vessel involved and different types of BMS were implanted. All-cause mortality was noted in 21% (n = 21) whereas cardiac mortality was seen in 16% (n = 16). Cumulative revascularisation free survival at 20 years was 71%. The study showed that long term outcomes after BMS implant were fare and acceptable.

Potential Mechanisms of In-stent Neointimal Atherosclerotic Plaque Formation

ABSTRACT

Percutaneous coronary intervention has become the main revascularization strategy for coronary artery disease. Compared with early percutaneous coronary angioplasty and the extensive clinical application of bare metal stents, drug-eluting stents can significantly reduce the stenosis caused by the elastic retraction of plaque and neoatherosclerosis (NA), but there is still a high incidence of in-stent restenosis (ISR), which restricts the clinical efficacy of stent implantation. In-stent neoatherosclerosis (ISNA), defined as atherosclerotic lesions in the neointima, is one of the main causes of late stent failure. ISNA plays an important role in stent thrombosis and ISR. The rate of target lesion revascularization and in-stent thrombosis is high when NA arises. Therefore, it is of great clinical significance to explore the occurrence of NA and its development mechanism after stent implantation to prevent ISR and improve stent implantation efficacy and associated clinical prognosis. In this article, we systematically reviewed the existing clinical research on ISNA and the role of optical coherence tomography in its evaluation.

Echocardiographic assessment before and after Percutaneous Transvenous Mitral Commissurotomy in patients with Rheumatic Mitral Stenosis

Objectives

To determine the changes produced in mitral valve morphology after Percutaneous Trans-Venous Mitral Commissurotomy.

Methods

Patients with mitral stenosis who underwent PTMC at the cardiology department of Lady Reading Hospital, Peshawar, Pakistan, from 2006-2016 were included in this study. All the data were manually obtained from the electronic medical record (M.F.E.). Wilkin's echocardiographic scoring system was used to assess the severity of mitral valve thickness, leaflet mobility, valvular calcification, and Subvalvular disease. The student t-test was used for mean comparison. P-value < 0.05 was considered significant.

Results

Of the total 229 patients, males were 96(41.9%), and females were 133(58.1%). The mean [SD] age of the patients was 25 ± 11years. The total Wilkin score was 7 ±1.5. 151(65.9%) were in New York Heart Association (NYHA) functional class III, and 78(34.1%) were in NYHA class IV. There was no immediate change after PTMC in systolic myocardial velocities (SV) measured at the lateral tricuspid annulus. The 2D mitral valve area increased from 0.98±0.94 cm² to 1.78 ± 0.44 cm² (P=0.001). Left Atrium diameter was 5.16±0.75 mm prior to PTMC, significantly decreased to 4.7± 0.7 mm (p=0.005) after PTMC. Ejection fraction (Left Ventricular Ejection Fraction) changed from 60.45± 8.25 mm Hg to 62.76±10 mm Hg (p=0.001). Mean Right Ventricular Ejection Fraction (RVEF) of patients before PTMC was 48.7 ± 4.7%, did not change significantly immediately after PTMC.

Conclusion

PTMC is associated with significant changes in mitral valve morphology in terms of splitting of the fused mitral commissures, increased MVA, improved leaflet excursion, and splitting of the subvalvular structures.

A Novel Rabbit Model for In-Stent Neoatherosclerosis

In-stent neoatherosclerosis is an important problem after percutaneous coronary intervention. To explore the mechanisms and treatment of in-stent neoatherosclerosis, an animal model is needed. To avoid the disadvantages of current animal models, such as excessive use of X-rays and a high mortality rate, we attempted to develop an improved animal model. We explored a method that uses a short time interval to establish a rabbit model of in-stent neoatherosclerosis with a high survival rate and to evaluate its indicators. Sixty rabbits were divided into three equal groups: group A, the traditional method; group B, the standard intervention method; and group C, the improved method. In group C, we made two small incisions in each rabbit's neck, separated the common carotid, punctured it, and implanted a stent. The incision was then sutured. Four weeks later, we used optical coherence tomography (OCT) to scan all rabbits for neoatherosclerosis. We found no significant differences in OCT data between our new animal model and the traditional and interventional groups (P > 0.05). The technological success rate was higher in the new animal model (P < 0.001). We developed a new method to establish an animal model of neoatherosclerosis, which had similar results to the traditional and interventional methods.

Small Tenuous Intracranial Arteries Can Well Tolerate the Deployment of 2 Stents in Y Configuration or an Overlapping Manner in Treating Intracranial Aneurysms

OBJECTIVE

To investigate parent vessel response to deployment of 2 stents for treatment of cerebral aneurysms.

METHODS

Fifteen patients (11 women and 4 men; age range, 25-83 years) with 18 wide-necked intracranial aneurysms were treated with 2 stents with or without subsequent coiling. The vascular diameter was measured and compared within the native parent artery, and the single stent and double stent were measured and compared before and immediately after stenting and at angiographic follow-up.

RESULTS

Thirty stents were deployed. Before stenting, the mean vessel diameter was 3.4 ± 0.21 mm at point A, 3.06 ± 0.18 mm at point B, 3.16 ± 0.21 mm at point C, 2.67 ± 0.27 mm at point D, and 2.56 ± 0.23 mm at point E. The deployment of 2 stents resulted in statistically significant increases in both the average vascular diameter and cross-sectional area at points C (3.51 ± 0.22 mm, P = 0.0006; and 9.76 ± 1.17 mm², P = 0.001, respectively) and E (2.88 ± 0.32 mm, P = 0.01; and 7.28 ± 1.46 mm², P = 0.02, respectively) compared with prestenting. At angiographic follow-ups, compared with before stenting, significant increases were documented at point C (3.42 ± 0.22 mm and 9.42 ± 1.37 mm², respectively) at first angiographic follow-up but at points A (3.62 ± 0.45 mm and 10.51 ± 2.37 mm², respectively) and B (3.26 ± 0.24 mm and 8.47±1.26 mm², respectively) at second angiographic follow-up. No significant vascular stenosis was demonstrated at the double-stent segment compared with the single-stent or native artery segments.

CONCLUSIONS

The small tenuous cerebral arteries can well tolerate the deployment of 2 stents for the treatment of intracranial aneurysms.

Long-term outcomes post chronic total occlusion intervention-implications of completeness of revascularization

BACKGROUND

Long term clinical outcomes post chronic total occlusion (CTO) intervention may depend not only on CTO success/failure alone but also on Completeness of revascularization.

OBJECTIVES

To determine long term outcomes post CTO intervention and relate them to both success versus failure and Complete Revascularization (CR) versus Incomplete Revascularization (IR).

METHODS

Consecutive patients taken up for CTO intervention with at-least one CTO vessel between Jan 2006 to Dec 2015 were included. Clinical, procedural and follow up details were recorded in a pre-specified custom made software. Primary endpoint of the study was survival free of major adverse event individual, death, myocardial infarction (MI), repeat revascularisation (percutaneous coronary intervention [PCI], or coronary artery bypass grafting (CABG) and recurrent or continued angina. Each individual adverse event was considered as a secondary end point.

RESULTS

A total of 632 patients were enrolled in study with follow up data available in 549 (86%) constituting the study group with 490 (89.3%) success and 59 (11.7%) failure. Complete revascularization (CR) was obtained in 410 (74.7%). Follow up was median 2.9 years with inter-quartile range 1.1-4.8 years. Kaplan Meier survival analysis showed a better EFS with both CTO success versus failure (P = 0.03)and CR versus IR (P = 0.017). Individual adverse outcomes however were not significantly different in CTO success versus failure group but significantly better when analyzed with respect to CR versus IR including death (P = 0.049) and recurrent angina (P = 0.024). Repeat intervention and MI were not different by either analysis.

CONCLUSIONS

Successful CTO PCI results in a better long term event free survival but the difference between the groups is more if analyzed with respect to completeness of revascularization rather than CTO success/failure alone.

Formation and Transformation of Neointima after Drug-eluting Stent Implantation: Insights from Optical Coherence Tomographic Studies

After coronary stent implantation, neointima formation resembles the wound healing process as it involves the sequential processes of inflammation, granulation, and remodeling. Because antiproliferative drugs and polymers of drug-eluting stents (DESs) delay vascular healing compared with bare metal stents, fibrin deposition can remain long after stent implantation, or inflammation can be excessive. Delayed vascular healing can be associated with adverse clinical outcomes including DES thrombosis or restenosis, and poor endothelization of DES neointima can accelerate neoatherosclerotic change inside the neointima, further contributing to luminal restenosis or neointimal instability. Despite the lack of correlation between pathologic and optical coherence tomography (OCT) findings, OCT assessments of neointima under various circumstances can reveal vascular responses to stent therapy. Homogeneous, heterogeneous, and layered neointima patterns can be recognized by OCT and can change with time. Homogeneous neointima might be associated with better clinical outcomes after DES implantation, whereas non-homogeneous neointima or neoatherosclerotic change can be associated with poorer clinical outcomes. However, limited data are currently available, and further studies are required to comprehensively address these questions.

Very long-term serial luminal changes after sirolimus-eluting stent implantation and progression process of very late stent failure

BACKGROUND

Very long-term angiographic results after sirolimus-eluting stent (SES) implantation have not been clarified. This study investigated serial angiographic results of early (<1year), late (1-5years), and very late (>5years) follow-up after SES implantation and the progression process to very late SES failure.

METHODS

We analyzed 631 lesions undergoing serial coronary angiography at early, late, and very late follow-up after SES implantation. The results of 205 lesions undergoing very late target lesion revascularization (VL-TLR; TLR beyond 5years) for acute coronary syndrome (ACS; 83) and non-ACS (122) were evaluated in comparison with 426 non-TLR lesions as a control group.

RESULTS

Non-TLR lesions showed no attenuated decline of minimum lumen diameter from postprocedure (2.51±0.47mm), early (2.37±0.58mm), late (2.22±0.60mm), up to very late (2.01±0.63mm) follow-up. In VL-TLR lesions, compared to non-TLR lesions, late lumen loss (LLL) from postprocedure to early follow-up was similar, but delayed LLL from early to late follow-up was significantly larger (0.25±0.48mm vs. 0.15±0.46mm, p=0.01). Although the delayed LLL was significantly larger in non-ACS lesions (0.29±0.44mm) than in non-TLR lesions (p<0.01), it was similar in ACS (0.19±0.52mm) and non-TLR lesions (p=0.54). Very delayed LLL from late to very late follow-up was 1.65±0.82mm in ACS lesions and 1.10±0.76mm in non-ACS lesions.

CONCLUSIONS

Progression of in-stent luminal narrowing did not attenuate beyond 5years after SES implantation. In very late SES failure, stent-related ACS lesions showed gradual luminal narrowing and subsequent rapid progression beyond 5years, whereas non-ACS lesions had progressive luminal narrowing within 5years.

Coronary stents and vascular response to implantation: literature review

Drug-eluting stents (DESs) have minimized the limitations of bare-metal stents (BMSs) after percutaneous coronary interventions. Nevertheless, serious concerns remain about possible late complications of stenting, such as stent thrombosis (ST) and in-stent restenosis (ISR), although the introduction of second-generation DESs seems to have softened the phenomenon, compared to the first-generation ones. ST is a potentially catastrophic event, which has been markedly reduced by optimization of stent implantation, novel stent designs, and dual antiplatelet therapy. The exact mechanism to explain its occurrence is under investigation, and, realistically, multiple factors are responsible. ISR of BMSs has been previously considered as a stable condition with an early peak (at 6 months) of intimal hyperplasia, followed by a regression period beyond 1 year. On the contrary, both clinical and histologic studies of DESs have demonstrated evidence of continuous neointimal growth during long-term follow-up, named "late catch-up" phenomenon. The acknowledgment that ISR is a relatively benign clinical condition has been recently challenged by evidences which reported that patients with ISR can experience acute coronary syndromes. Intracoronary imaging is an invasive technology that allows identifying features of atherosclerotic plaque of stent implanted and of vascular healing after stenting; it is often used to complete diagnostic coronary angiography and to drive interventional procedures. Intracoronary optical coherence tomography is currently considered a state-of-the-art imaging technique; it provides, compared to intravascular ultrasound, better resolution (at least >10 times), allowing the detailed characterization of the superficial structure of the vessel wall. Imaging studies "in vivo," in agreement with histological findings, suggest that chronic inflammation and/or endothelial dysfunction may induce late de novo "neoatherosclerosis" inside both BMSs and DESs. So, neoatherosclerosis has become the prime suspect in the pathogenesis of late stent failure.

miR-125a-5p Modulates Phenotypic Switch of Vascular Smooth Muscle Cells by Targeting ETS-1

MicroRNAs are key regulators of vascular smooth muscle cells (VSMCs) phenotypic switch, one of the main events responsible for bare metal in-stent restenosis after percutaneous coronary intervention. miR-125a-5p is an important modulator of differentiation, proliferation, and migration in different cell types; however, its role in VSMCs is still unknown. The aim of this study was to evaluate the role of miR-125a-5p in VSMCs phenotypic switch. Our results suggest that miR-125a-5p is highly expressed in VSMCs, but it is down-regulated after vascular injury in vivo. Its overexpression is sufficient to reduce VSMCs proliferation and migration, and it is able to promote the expression of selective VSMCs markers such as alpha smooth muscle actin, myosin heavy chain 11, and smooth muscle 22 alpha. Interestingly, miR-125a-5p directly targets ETS-1, a transcription factor implicated in cell proliferation and migration and is crucial in PDGF-BB pathway in VSMCs. Thus, miR-125a-5p in this context inhibits PDGF-BB pathway and is therefore a potential regulator of VSMCs phenotypic switch.

Difference of Tissue Characteristics Between Early and Late Restenosis After Second-Generation Drug-Eluting Stents Implantation - An Optical Coherence Tomography Study

BACKGROUND

The mechanism and time course of in-stent restenosis (ISR) after implantation of second-generation DES have not yet been fully elucidated. We sought to evaluate the differences in tissue characteristics between the different phases of ISR after second-generation DES implantation using optical coherence tomography (OCT).

METHODS AND RESULTS

From June 2010 to December 2015, 324 consecutive patients with 337 ISR lesions underwent OCT. Of these, we analyzed 53 lesions in 53 patients who had their first ISR after second-generation DES implantation and underwent OCT before any procedures. According to the timing of ISR, the patients were divided into the early group (within 1 year: E-ISR, n=30) and late group (beyond 1 year: L-ISR, n=23). Quantitative parameters and qualitative characteristics of the neointima were evaluated. In the minimum lumen area site analysis, the E-ISR group had more frequently homogeneous intima than the L-ISR group (26.7% vs. 4.4%, P=0.02). The frequencies of neointima with lipid-laden, thin-cap fibroatheroma, neovascularization and macrophage infiltration were significantly higher in the L-ISR group than in the E-ISR group (30.0% vs. 69.6%, P<0.01; 0.0% vs. 26.1%, p <0.01; 6.7% vs. 26.1%, P=0.049; 3.3% vs. 26.1%, P=0.01, respectively).

CONCLUSIONS

Neointimal tissue characteristics differed between E-ISR and L-ISR after second-generation DES implantation. E-ISR was mainly caused by neointimal hyperplasia, whereas neoatherosclerosis was the main mechanism of L-ISR.

MicroRNAs for Restenosis and Thrombosis After Vascular Injury

Percutaneous revascularization revolutionized the therapy of patients with coronary artery disease. Despite continuous technical advances that substantially improved patients' outcome after percutaneous revascularization, some issues are still open. In particular, restenosis still represents a challenge, even though it was dramatically reduced with the advent of drug-eluting stents. At the same time, drug-eluting stent thrombosis emerged as a major concern because of incomplete or delayed re-endothelialization after vascular injury. The discovery of microRNAs revealed a previously unknown layer of regulation for several biological processes, increasing our knowledge on the biological mechanisms underlying restenosis and stent thrombosis, revealing novel promising targets for more efficient and selective therapies. The present review summarizes recent experimental and clinical evidence on the role of microRNAs after arterial injury, focusing on practical aspects of their potential therapeutic application for selective inhibition of smooth muscle cell proliferation, enhancement of endothelial regeneration, and inhibition of platelet activation after coronary interventions. Application of circulating microRNAs as potential biomarkers is also discussed.

Optical coherence tomography to evaluate coronary stent implantation and complications

Coronary optical coherence tomography (OCT) is now an established imaging technique in many catheterization laboratories worldwide. With its near-histological view of the vessel wall and lumen interface, it offers unprecedented imaging quality to improve our understanding of the pathophysiology of atherosclerosis, plaque vulnerability, and vascular biology. Not only is OCT used to accurately detect atherosclerotic plaque and optimize stent position, but it can further characterize plaque composition, quantify stent apposition, and assess stent tissue coverage. Given that its resolution of 15 μm is well above that of angiography and intravascular ultrasound, OCT has become the invasive imaging method of choice to examine the interaction between stents and the vessel wall. This review focuses on the application of OCT to examine coronary stents, the mechanisms of stent complications, and future directions of OCT-guided intervention.

Can the optimal type of stent be predicted based on clinical risk factors? A subgroup analysis of the randomized BASKET-PROVE trial

BACKGROUND

The randomized BASKET-PROVE study showed no significant differences between sirolimus-eluting stents (SES), everolimus-eluting stents (EES), and bare-metal stents (BMS) with respect to the primary end point, rates of death from cardiac causes, or myocardial infarction (MI) at 2 years of follow-up, in patients requiring stenting of a large coronary artery. Clinical risk factors may affect clinical outcomes after percutaneous coronary interventions. We present a retrospective analysis of the BASKET-PROVE data addressing the question as to whether the optimal type of stent can be predicted based on a cumulative clinical risk score.

METHODS

A total of 2,314 patients (mean age 66 years) who underwent coronary angioplasty and implantation of ≥1 stents that were ≥3.0 mm in diameter were randomly assigned to receive SES, EES, or BMS. A cumulative clinical risk score was derived using a Cox model that included age, gender, cardiovascular risk factors (hypercholesterolemia, hypertension, family history of cardiovascular disease, diabetes, smoking), presence of ≥2 comorbidities (stroke, peripheral artery disease, chronic kidney disease, chronic rheumatic disease), a history of MI or coronary revascularization, and clinical presentation (stable angina, unstable angina, ST-segment elevation MI).

RESULTS

An aggregate drug-eluting stent (DES) group (n = 1,549) comprising 775 patients receiving SES and 774 patients receiving EES was compared to 765 patients receiving BMS. Rates of death from cardiac causes or nonfatal MI at 2 years of follow-up were significantly increased in patients who were in the high tertile of risk stratification for the clinical risk score compared to those who were in the aggregate low-mid tertiles. In patients with a high clinical risk score, rates of death from cardiac causes or nonfatal MI were lower in patients receiving DES (2.4 per 100 person-years, 95% CI 1.6-3.6) compared with BMS (5.5 per 100 person-years, 95% CI 3.7-8.2, hazard ratio 0.45, 95% CI 0.26-0.80, P = .007). However, they were not significantly different between receivers of DES and BMS in patients in the low-mid risk tertiles.

CONCLUSIONS

This exploratory analysis suggests that, in patients who require stenting of a large coronary artery, use of a clinical risk score may identify those patients for whom DES use may confer a clinical advantage over BMS, beyond lower restenosis rates.

Neoatherosclerosis in Very Late Stenosis of Bare Metal Stent by Optical Coherence Tomography

Bare metal stents (BMS) continue to be widely used in patients with coronary artery disease undergoing percutaneous revascularization. Progressive luminal renarrowing has been reported late after BMS implantation resulting in a significant rate of stent failure events. We present a case of very late BMS failure due to in-stent restenosis where optical coherence tomography (OCT) was used to demonstrate neoatherosclerosis as the underlying mechanism. We provide a brief review of neoatherosclerosis and showcase salient features on OCT evaluation.

Neoatherosclerosis: Coronary stents seal atherosclerotic lesions but result in making a new problem of atherosclerosis

Chronic inflammation of the native vessel wall with infiltration of lipid-laden foamy macrophages through impaired endothelium results in atherosclerosis. Percutaneous coronary intervention, including metallic stent implantation, is now widely utilized for the treatment of atherosclerotic lesions of the coronary artery. Bare-metal stents and the subsequently developed drug-eluting stents seal the atherosclerosis and resolve lumen stenosis or obstruction of the epicardial coronary artery and myocardial ischemia. After stent implantation, neointima proliferates within the stented segment. Chronic inflammation caused by a foreign body reaction to the implanted stent and subsequent neovascularization, which is characterized by the continuous recruitment of macrophages into the vessel, result in the transformation of the usual neointima into an atheromatous neointima. Neointima with an atherosclerotic appearance, such as that caused by thin-cap fibroatheromas, is now recognized as neoatherosclerosis, which can sometimes cause in-stent restenosis and acute thrombotic occlusion originating from the stent segment following disruption of the atheroma. Neoatherosclerosis is emerging as a new coronary stent-associated problem that has not yet been resolved. In this review article, we will discuss possible mechanisms, clinical challenges, and the future outlook of neoatherosclerosis.

Stent thrombosis and restenosis: what have we learned and where are we going? The Andreas Grüntzig Lecture ESC 2014

Modern-day stenting procedures leverage advances in pharmacotherapy and device innovation. Patients treated with contemporary antiplatelet agents, peri-procedural antithrombin therapy and new-generation drug-eluting stents (DES) have excellent outcomes over the short to medium term. Indeed, coupled with the reducing costs of these devices in most countries there remain very few indications where patients should be denied treatment with standard-of-care DES therapy. The two major causes of stent failure are stent thrombosis (ST) and in-stent restenosis (ISR). The incidence of both has reduced considerably in recent years. Current clinical registries and randomized trials with broad inclusion criteria show rates of ST at or <1% after 1 year and ∼0.2-0.4% per year thereafter; rates of clinical ISR are 5% respectively. Angiographic surveillance studies in large cohorts show rates of angiographic ISR of ∼10% with new-generation DES. The advent of high-resolution intracoronary imaging has shown that in many cases of late stent failure neoatherosclerotic change within the stented segment represents a final common pathway for both thrombotic and restenotic events. In future, a better understanding of the pathogenesis of this process may translate into improved late outcomes. Moreover, the predominance of non-stent-related disease as a cause of subsequent myocardial infarction during follow-up highlights the importance of lifestyle and pharmacological interventions targeted at modification of the underlying disease process. Finally, although recent developments focus on strategies which circumvent the need for chronically indwelling stents--such as drug-coated balloons or fully bioresorbable stents-more data are needed before the wider use of these therapies can be advocated.

In-stent neointimal characteristics and late neointimal response after drug-eluting stent implantation: A preliminary observation

BACKGROUND

Progressive neointimal proliferation may lead to late restenosis and/or neoatherosclerosis after drug-eluting stent (DES) implantation. Late neointimal response may be different among different tissue characteristics. The aim of this study was to assess impact of in-stent neointimal characteristics on late neointimal response following DES implantation.

METHODS

Serial (median 270 days and median 551 days after stent implantation) optical coherence tomography (OCT) examinations were performed in 42 stented lesions from 26 patients. In-stent neointimal tissue was categorized as either homogeneous or heterogeneous neointima based on the OCT appearance at 1st follow-up. Serial changes in neointimal area (NIA) were compared between lesions with homogeneous neointima and those with heterogeneous neointima.

RESULTS

At first follow-up, homogeneous neointima was observed in 22 (52%) and heterogeneous neointima in 20 (48%) lesions, respectively. During follow-up, NIA in lesions with homogeneous neointima decreased significantly (1.8±0.93 mm(2) to 1.5±0.88 mm(2), p<0.001). On the other hand, NIA in lesions with heterogeneous neointima did not change significantly (2.7±1.8 mm(2) to 2.8±1.6 mm(2), p=0.658). Homogeneous neointima was the only predictor of late neointimal regression (late neointimal regression defined as NIA at first follow-up - NIA at second follow-up <0) by multivariable analysis (odds ratio=7.591, 95% confidence interval: 1.616-35.67, p=0.010).

CONCLUSIONS

OCT characteristics of neointima after DES implantation may be related to late neointimal progression or regression.

Bare-metal stent thrombosis two decades after stenting

Very late bare-metal stent (BMS) thrombosis is unusual in clinical practice. To the best of our knowledge, the latest that the thrombosis of a BMS has been reported is 14 years after implantation. Here, we describe a case of BMS thrombosis that occurred two decades after stenting. A 68-year-old male patient was admitted with acute anterior myocardial infarction. This patient had a history of BMS implantation in the left anterior descending coronary artery (LAD) 20 years previously. Immediate coronary angiography demonstrated acute thrombotic occlusion of the stent in the LAD. With this case, we are recording the latest reported incidence of BMS thrombosis after implantation.

Serial changes of neointimal tissue after everolimus-eluting stent implantation in porcine coronary artery: an optical coherence tomography analysis

Purposes. The serial changes in neointimal tissues were compared between everolimus-eluting stent (EES) and bare-metal stent (BMS) in the porcine coronary artery using optical coherence tomography (OCT). Methods. Serial (1, 3, and 6 month follow-up after stent implantation) OCT examinations were performed in 15 swine with 15 BMS- and 15 EES-treated lesions in porcine coronary arteries. Results. In BMS-implanted lesions, neointimal volume decreased from 7.3 mm³ to 6.9 mm³ and 6.4 mm³ at 1, 3, and 6 months follow-up without statistical significance (P = 0.369). At the time points of 1, 3, and 6 months, neointimal tissue appearance was mainly a homogeneous pattern (80.0%, 93.3%, and 100%, resp.), while the other pattern was layered. In contrast, in EES-implanted lesions, neointimal volume significantly increased from 4.8 mm³ to 9.8 mm³ between 1 and 3 months but significantly decreased to 8.6 mm³ between 3 and 6 months (P < 0.001). Between 1 and 3 months, the layered pattern of neointimal tissue increased from 26.7% to 66.7% but decreased to 20.0% between 3 and 6 months. Conclusions. EES had a biphasic pattern of neointimal amounts that correlated with changes in neointimal morphology.

Meeting the Unmet - The Cre8 Polymer-free Drug-eluting Stents Technology: Proceedings of a satellite symposium held at EuroPCR on May 20th - 23rd 2014 in Paris

The use of first-generation drug-eluting stents (DES) has been associated with safety concerns such as very late stent thrombosis. Today, with the release of newer DES, there is a need for comparative studies of percutaneous coronary intervention (PCI) versus coronary artery bypass grafting (CABG) to demonstrate their value in patients with high risk of restenosis such as diabetic patients. In a satellite symposium presented at EuroPCR 2014, the Cre8™ DES was discussed. The Cre8 device has a number of unique clinical features, including polymer-free technology, abluminal reservoir technology and bio-inducer surface that ensure effective neointima suppression and rapid endothelialisation. The efficacy of the Cre8 DES has been demonstrated in the International randomised comparison between DES Limus Carbostent and Taxus drug-eluting stents in the treatment of de novo coronary lesions (NEXT) randomised clinical study, with equivalent efficacy in the diabetic and general populations, a unique finding. Ongoing clinical studies such as Investig8 and the Tel Aviv Medical Center (TLVMC) Cre8 study have confirmed the efficacy of the device in patient populations with a high proportion of diabetic patients. The Demonstr8 randomised trial has shown almost complete Cre8 strut coverage at three months with a numerical advantage versus bare metal stent (bare metal stents [BMS] - comparator device) at one month. In addition, use of the Cre8 DES may enable a shorter duration of dual antiplatelet therapy (DAPT) following PCI. The Cre8 DES therefore represents a significant advance in stent technology and may be particularly useful in challenging clinical settings.

Switching types of drug-eluting stents does not prevent repeated in-stent restenosis in patients with coronary drug-eluting stent restenosis

OBJECTIVES

We treated patients experiencing drug-eluting stent (DES) restenosis with plain old balloon angioplasty (POBA), implantation of the same type of DES [homogeneous drug-eluting stent (HOMO-DES)], or implantation of a different type of DES [heterogeneous drug-eluting stent (HETERO-DES)], and compared the efficacy and safety of these procedures for the prevention of repeated in-stent restenosis (ISR).

BACKGROUND

In patients with de-novo coronary lesions, DES implantation is associated with a markedly reduced restenosis rate as compared with that associated with a bare metal stent and POBA. However, the optimal management strategy for patients with DES ISR remains unknown.

PATIENTS AND METHODS

We identified 191 consecutive DES ISR lesions from 183 patients who required clinically driven revascularization and divided them into three groups according to the treatment: 38 lesions were treated with POBA, 38 with HOMO-DES, and 115 with HETERO-DES.

RESULTS

The incidence of target lesion revascularization (TLR) was 42.1% (16/38), 15.8% (6/38), and 16.5% (19/115) in the POBA, HOMO-DES, and HETERO-DES groups (POBA vs. HOMO, HETERO-DES; P=0.002, respectively). Multivariate analysis indicated that diabetes [odds ratio (OR), 3.4], hemodialysis (OR, 7.74), nonfocal ISR patterns (OR, 3.35), previous myocardial infarction (OR, 3.26), and POBA (OR, 8.84) were independent predictors of TLR.

CONCLUSION

A strategy involving repeated DES implantation was superior to POBA for preventing recurrent restenosis. Treatment with a different type or generation of DES does not appear to reduce the incidence of TLR. Moreover, we identified certain useful factors for facilitating appropriate and early triage in the patients with repeated DES ISR.

Clinical and angiographic outcomes after intracoronary bare-metal stenting

Background

Data from a large patient population regarding very long-term outcomes after BMS implantation are inadequate. This study aimed to evaluate the very long-term (8–17 years) clinical and long-term (3–5 years) angiographic outcomes after intracoronary bare-metal stenting (BMS).

Methods and Results

From the Cardiovascular Atherosclerosis and Percutaneous TrAnsluminal INterventions (CAPTAIN) registry, a total of 2391 patients with 2966 lesions treated with 3190 BMSs between November 1995 and May 2004 were evaluated. In total, 1898 patients with 2364 lesions, and 699 patients with 861 lesions underwent 6-month and 3- to 5- year angiographic follow-up, respectively. During a mean follow-up period of 149±51 months, 18.6% of the patients died (including 10.8% due to cardiac death), 6.1% developed reinfarction, 16.2% had target lesion revascularization (including 81% of the patients within the first year), 14.5% underwent new lesion stenting (including 72% of the patients after 3 years), 2.4% underwent coronary bypass surgery, and 1.6% had definite stent thrombosis. The overall cardiovascular event-free survival rate was 58.5%. The 6-month angiographic study indicated a 20% restenosis rate. The minimal luminal diameter increased from 0.65±0.44 mm to 3.02±0.46 mm immediately after stenting, decreased to 2.06±0.77 mm at the 6-month follow-up, and increased to 2.27±0.68 mm at the 3- to 5-year follow-up.

Conclusions

This study provides clinical and angiographic results from a large population of patients who underwent BMS implantations after a long-term follow-up period (149±51 months). The progression of coronary atherosclerosis developed over time, and presented with new lesion required stent implantation. The follow-up angiographic findings reconfirmed the late and sustained improvement in luminal diameter between 6 months and 3–5 years.

Enterprise stenting for intracranial aneurysm treatment induces dynamic and reversible age-dependent stenosis in cerebral arteries

BACKGROUND

Although intracranial stenting has been associated with in-stent stenosis, the vascular response of cerebral vessels to the deployment of the Enterprise vascular reconstruction device is poorly defined.

OBJECTIVE

To evaluate the change in parent vessel caliber that ensues after Enterprise stent placement.

METHODS

Seventy-seven patients with 88 aneurysms were treated using Enterprise stent-assisted coil embolization and underwent high-resolution three-dimensional rotational angiography followed by three-dimensional edge-detection filtering to remove windowing-dependence measurement artifact. Orthogonal diameters and cross-sectional areas (CSAs) were measured proximal and distal on either side of the leading stent edge (points A, B), trailing stent edge (points D, E), and at mid-stent (point C).

RESULTS

Enterprise stent deployment caused an instant increase in the parent artery CSA by 8.98% at D, which was followed 4-6 months later by significant in-stent stenosis (15.78% at A, 27.24% at B, 10.68% at C, 32.12% at D, and 28.28% at E) in the stented artery. This time-dependent phenomenon showed resolution which was complete by 12-24 months after treatment. This target vessel stenosis showed significant age dependence with greater response in the young. No flow-limiting stenosis requiring treatment was observed in this series.

CONCLUSIONS

Use of the Enterprise stent is associated with a significant dynamic and spontaneously resolvable age-dependent in-stent stenosis. Further study is warranted on the clinical impact, if any, of this occurrence.

Late catch-up in lumen diameter at five-year angiography in MACE-free patients treated with sirolimus-eluting stents in the Primary Stenting of Totally Occluded Native Coronary Arteries: a randomised comparison of bare metal stent implantation with sirolimus-eluting stent implantation for the treatment of total coronary occlusions (PRISON II)

AIMS

The present study was designed to examine the five-year angiographic follow-up of MACE-free patients enrolled in the PRISON II study.

METHODS AND RESULTS

In the PRISON II study a total of 200 patients were randomised to either bare metal stents (BMS) or sirolimus-eluting stents (SES) after successful recanalisation of total coronary occlusions (TCO). Patients free of MACE with available angiography at six months were approached for repeated angiography at five years. The primary endpoint was in-stent very late luminal loss (VLLL) at five years. The secondary endpoint was additional late luminal loss (ALLL) between six months and five years. At five years, repeated angiography was performed in 72 patients, 50/82 (61%) in the SES group and 22/58 (38%) in the BMS group. In-stent VLLL was lower in the SES group (0.19 mm ± 0.72 vs. 0.51 mm ± 0.71, p=0.09) compared to the BMS group and in-segment VLLL was comparable in both groups (0.01 mm±0.58 vs. 0.03 mm ± 0.73, p=0.89). Late catch-up in lumen diameter was observed in the SES group with a trend towards increased ALLL compared to the BMS group (in-stent, 0.35 mm ± 0.88 vs. 0.04 mm ± 0.81, p=0.16; in-segment, 0.20 mm ± 0.74 vs. -0.05 mm ± 0.73, p=0.19).

CONCLUSIONS

At five-year angiographic follow-up, late catch-up was observed after successful recanalisation of TCOs treated with SES. Despite a late catch-up, the angiographic results of SES were superior in-stent and similar in-segment compared to BMS.

Drug-eluting stents: from evidence to policy

Drug-eluting stents are a major breakthrough in cardiology, with the Cypher (Cordis Corporation) and Taxus (Boston Scientific) stents preventing 60-70% of repeat coronary revascularizations, compared with bare metal stents. Both evidence- and risk-based application of drug-eluting stents is expected to create relevant financial and equity problems to most public hospitals, as the cost of drug-eluting stents is over 1000 higher than traditional stents. In the perspective of third-party payers, drug-eluting stents are cost-effective revascularization strategies for a large portion of patients actually undergoing stenting. However, adequate guidelines and reimbursement strategies are still awaited in several countries.

Contributors to newly developed coronary artery disease in patients with a previous history of percutaneous coronary intervention beyond the early phase of restenosis

OBJECTIVE

The low-density lipoprotein cholesterol (LDL-C)/high-density lipoprotein cholesterol (HDL-C) ratio is considered to be a sensitive marker of the risk of atherosclerotic cardiovascular disease; however, in patients with a previous history of percutaneous coronary intervention (PCI), there is little information regarding the predictive value of this parameter beyond the period of early restenosis. The aim of this study was to investigate contributing factors to newly developed coronary artery disease in patients with a previous history of PCI after stabilization.

METHODS

The clinical characteristics of 238 patients with a previous history of PCI who underwent coronary angiography following recurrent cardiac ischemia beyond the period of early restenosis were examined.

RESULTS

Overall, 64% of the patients underwent late revascularization, while 31% and 50% underwent late target lesion revascularization and new lesion revascularization, respectively. A multivariate analysis identified the LDL-C/HDL-C ratio to be an independent contributor to late revascularization (hazard ratio (HR), 1.37; p<0.001). Similarly, the independent contributors to late target lesion revascularization and new lesion revascularization were the non-HDL-C level and LDL-C/HDL-C ratio, respectively. Based on the median value of the LDL-C/HDL-C ratio, the patients were classified into high and low LDL-C/HDL-C ratio groups. The log-rank test revealed a significantly higher incidence of late revascularization in the high-LDL-C/HDL-C ratio group than in the low-LDL-C/HDL-C ratio group among the patients with an LDL-C level of ≥ 100 mg/dL (p=0.011). However, the difference between the two groups was diminished among the patients with an LDL-C level of <100 mg/dL (p=0.047), and only diabetes mellitus (HR, 2.239; p=0.009) was found to be an independent contributor to late coronary revascularization in these patients.

CONCLUSION

The LDL-C/HDL-C ratio is an important contributor to the development of new coronary artery disease in patients with a previous history of PCI beyond the period of early restenosis, particularly among patients with an LDL-C level of ≥ 100 mg/dL.

Long-term safety of drug-eluting stents

Stent implantation in coronary stenosis has revolutionized the treatment of coronary artery disease. The introduction of antirestenotic drug coatings further improved their efficacy in reducing target vessel revascularizations. With increasing use of drug-eluting stents (DES), stent thrombosis (ST) rose as potentially fatal major complication. Initially, the incidence of ST late after stent implantation seemed to be similar for DES and bare metal stents until several studies proved otherwise in first-generation DES. Since then, the design and components of DES have been changed and new polymers, drugs and different combinations of platelet inhibitors have been introduced to further improve the safety of DES. In this review, the authors focus on the relationship between DES, lesion anatomy, implantation technique and pharmacology to avoid the occurrence of ST. Furthermore, the relationship between dual antiplatelet therapy, bleeding rate and its significant impact on patient outcome is discussed. Finally, some promising future concepts are highlighted.

Regression of coronary disease after bypass surgery: Urban myth or common finding?

OBJECTIVES

Coronary artery disease has been viewed as a relentless, progressive disease. We sought to describe the prevalence and distribution of regression of native vessel disease in coronary artery bypass patients and characterize its relationship with bypass grafting.

METHODS

Among 619 patients who underwent bypass surgery in a radial artery trial, 405 had follow-up angiography available a mean of 6.2 ± 3.1 years (range, 0-14) after surgery. The percentage of diameter stenosis of each major native coronary vessel was reported by 3 cardiac specialists and classified into grades of nonflow limiting (0%-39%), moderate (40%-69%), flow limiting (70%-80%), severely stenosed (81%-99%), and occluded (100%). Native vessel disease regression was defined as decrease in 1 or more grades of stenosis between the pre- and postoperative angiograms.

RESULTS

A total of 1742 native coronary arteries had preoperative stenosis of at least 40% and were included in the present analysis, receiving 753 arterial grafts and 391 saphenous vein grafts. Overall, the prevalence of disease regression was 19.7%, and 45% of patients demonstrated regression in 1 or more vessels. The presence of an arterial graft increased the likelihood of disease regression (21.3% compared with 16% for venous bypassed vessels, P = .012) as did the location in the left circulation (22.6% compared with 13.9% for the right circulation, P < .001) and having a flow-limiting (≥70%) lesion (21.9% compared with 9.8% for moderate lesions, P < .001).

CONCLUSIONS

Native coronary artery disease regression after coronary artery bypass grafting is common and affected by conduit type, vessel location, and lesion severity. Surgeons must consider these factors when assessing the requirement for bypass grafts in a borderline lesion.

A rare mechanism of very late bare metal stent thrombosis--role of optical coherence imaging in its evaluation and management

Very late stent thrombosis is an uncommon event following implantation with bare metal stents (BMS) in coronary arteries. Long term follow up studies have shown that a small number of BMS develop very late thrombosis following years of stability. Atherosclerotic transformation of neointimal tissue is increasingly being recognised as the cause of these adverse events. A 49 year-old male presented with acute inferior wall myocardial infarction resulting from thrombosis of the BMS implanted in his right coronary artery five years earlier. He was successfully thrombolysed and his coronary angiogram showed mild diffuse instent restenosis. The intravascular optical coherence tomography revealed instent neoatherosclerotic plaque rupture without any flow limiting stenosis as the likely culprit event.