Three-year follow-up after implantation of metallic coronary-artery stents

Tooth Loss is a Risk Factor for Cardiovascular Disease Mortality: A Systematic Review with Meta-analyses

INTRODUCTION

The current evidence linking tooth loss and cardiovascular disease mortality is inconclusive. Thus, the aim of this systematic review was to explore the association between tooth loss and cardiovascular disease (CVD) mortality.

METHODS

A comprehensive literature search of databases and gray literature included: Web of Science, Scopus, PubMed, Cochrane Central Register of Controlled Trials, Google Scholar, various digital repositories. The included studies reported on CVD mortality and tooth loss. The Newcastle-Ottawa scale was used to assess the quality of included studies. Random-effects meta-analysis method, sub-group analysis (based on the tooth loss categories (edentulous and fewer than 10 teeth present), meta-regression (based on the number. of confounders), publication bias, and sensitivity analysis were performed.

RESULTS

Twelve articles met the eligibility criteria with an overall "Good" quality. A significant association between tooth loss (edentulous or less than 10 teeth present) and CVD mortality was found in the primary meta-analysis, which compiled data from 12 studies. The estimated hazard ratio was 1.66 (95% CI: 1.32-2.09), and there was high heterogeneity (I2 = 82.42). Subgroup analysis revealed that the edentulous subgroup showed a higher risk with no significant heterogeneity, while the subgroup with fewer than 10 teeth showed a higher risk with substantial heterogeneity. Meta-regression analysis did not reveal any significant impact (P = .626) on whether variations in the number of confounders across studies would substantially affect the overall findings. No publication bias was detected and the sensitivity analysis based on the critical confounders also confirmed that tooth loss as a risk factor for CVD mortality (hazard ratio = 1.52, 95% CI: 1.28-1.80), (I2 51.82%).

CONCLUSION

The present systematic review reported that being edentulous or having lesser than 10 teeth is a predictive indicator of CVD mortality.

Advantages of DES over BMS in Preventing the Risk of Myocardial Infarction, Ischemic Stroke, and Mortality in Various Populations

Backgrounds: Previous studies have demonstrated that drug-eluting stents (DESs) are more effective than bare metal stents (BMSs) in reducing the risk of myocardial infarction in the short term, but the long-term preventive benefits for myocardial infarction, ischemic stroke, and mortality are not clear. Objective: This study deeply analyzed the long-term (within 3 years) advantages of the use of DESs in preventing the risk of myocardial infarction, ischemic stroke, and mortality in various populations compared with those of using BMSs. Methods: This was a retrospective observational cohort study. We used the 2015-2019 claims data from Taiwan's National Health Insurance Research Database. Patients over the age of 18 who underwent coronary stent placement (both DESs and BMSs) for the first time in 2016 were included in the study population. Propensity-score matching was applied to increase the comparability of the DES and BMS groups. We used a Cox proportional hazard regression analysis to compare the effectiveness of DESs and BMSs in preventing myocardial infarction, ischemic stroke, and all-cause mortality. A subgroup analysis was also performed. Results: In total, 21,608 cases were included in this study. Overall, the risk of myocardial infarction (aHR = 0.82; 95% CI: 0.78-0.85), ischemic stroke (aHR = 0.88; 95% CI: 0.81-0.95), and mortality (aHR = 0.61; 95% CI: 0.57-0.65) in the DES group were significantly lower than those in the BMS group. However, in some special cases, the results were not statistically significant. In particular, in patients with obesity (aHR = 2.61; 95% CI: 1.20-5.69), the DES group appeared to have a significantly higher long-term intermediate ischemic risk than the BMS group. Conclusions and Relevance: In conclusion, although DESs were more effective than BMSs in reducing the risk of long-term myocardial infarction, ischemic stroke, and mortality, this study also found that, in some cases, the advantages of DESs over BMSs were not clearly observed.

A multiphysics modeling approach for in-stent restenosis: Theoretical aspects and finite element implementation

Development of in silico models that capture progression of diseases in soft biological tissues are intrinsic in the validation of the hypothesized cellular and molecular mechanisms involved in the respective pathologies. In addition, they also aid in patient-specific adaptation of interventional procedures. In this regard, a fully-coupled high-fidelity Lagrangian finite element framework is proposed within this work which replicates the pathology of in-stent restenosis observed post stent implantation in a coronary artery. Advection-reaction-diffusion equations are set up to track the concentrations of the platelet-derived growth factor, the transforming growth factor-β, the extracellular matrix, and the density of the smooth muscle cells. A continuum mechanical description of volumetric growth involved in the restenotic process, coupled to the evolution of the previously defined vessel wall constituents, is presented. Further, the finite element implementation of the model is discussed, and the behavior of the computational model is investigated via suitable numerical examples. Qualitative validation of the computational model is presented by emulating a stented artery. Patient-specific data are intended to be integrated into the model to predict the risk of in-stent restenosis, and thereby assist in the tuning of stent implantation parameters to mitigate the risk.

Evolution of drug-eluting coronary stents: a back-and-forth journey from the bench-to-bedside

Coronary stents have revolutionized the treatment of coronary artery disease. Compared with balloon angioplasty, bare-metal stents effectively prevented abrupt vessel closure but were limited by in-stent restenosis due to smooth muscle cell proliferation and neointimal hyperplasia. The first-generation drug-eluting stent (DES), with its antiproliferative drug coating, offered substantial advantages over bare-metal stents as it mitigated the risk of in-stent restenosis. Nonetheless, they had several design limitations that increased the risk of late stent thrombosis. Significant advances in stent design, including thinner struts, enhanced polymers' formulation, and more potent antiproliferative agents, have led to the introduction of new-generation DES with a superior safety profile. Cardiologists have over 20 different DES types to choose from, each with its unique features and characteristics. This review highlights the evolution of stent design and summarizes the clinical data on the different stent types. We conclude by discussing the clinical implications of stent design in high-risk subsets of patients.

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.

Gradual Expansion of a Stent to Prevent Periprocedural Complications after Carotid Artery Stenting for Vulnerable Severe Stenotic Lesions with Intraplaque Hemorrhages: A Retrospective Observational Study

Vulnerable lesions with intraplaque hemorrhages are associated with a high incidence of complications following carotid artery stenting (CAS). CAS for vulnerable lesions has not been established; therefore, we gradually expand stents in such patients. This study aimed to compare the incidences of complications between gradual-expansion CAS for vulnerable lesions and standard CAS for non-vulnerable lesions. For gradual-expansion CAS, we used 3.0 or 4.0 mm balloons for minimal luminal diameters (MLDs) <2.0 or ≥2.0 mm, respectively, for pre-stenting angioplasty (SA) and did not overinflate them. By contrast, for standard CAS, we used a 4.0 mm balloon and overinflated it to 4.23 mm. A closed-cell stent was deployed, and post-SA was not performed in both groups. We evaluated the MLD before and minimal stent diameter (MSD) immediately after CAS, as well as periprocedural complications of combined stroke, death, and myocardial infarction within 30 days after CAS. In the vulnerable and non-vulnerable groups, 30 and 38 patients were analyzed, the MLDs were 0.76 and 0.96 mm before CAS, the MSDs were 2.97 mm and 3.58 mm after CAS, and the numbers of complications were 0 and 1, respectively. Gradual-expansion CAS for vulnerable lesions was as safe as standard CAS for non-vulnerable lesions.

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.

Development of a polycaprolactone/poly(p-dioxanone) bioresorbable stent with mechanically self-reinforced structure for congenital heart disease treatment

Recent progress in bioresorbable stents (BRSs) has provided a promising alternative for treating coronary artery disease. However, there is still lack of BRSs with satisfied compression and degradation performance for pediatric patients with congenital heart disease, leading to suboptimal therapy effects. Here, we developed a mechanically self-reinforced composite bioresorbable stent (cBRS) for congenital heart disease application. The cBRS consisted of poly(p-dioxanone) monofilaments and polycaprolactone/poly(p-dioxanone) core-shell composite yarns. Interlacing points in cBRS structure were partially bonded, offering the cBRS with significantly higher compression force compared to typical braids and remained good compliance. The suitable degradation profile of the cBRS can possibly preserve vascular remodeling and healing process. In addition, the controllable structural organization provides a method to customize the performance of the cBRS by altering the proportion of different components in the braids. The in vivo results suggested the cBRS supported the vessel wall similar to that of metallic stent. In both abdominal aorta and iliac artery of porcine, cBRS was entirely endothelialized within 1 month and maintained target vessels with good patency in the 12-month follow-up. The in vivo degradation profile of the cBRS is consistent with static degradation results in vitro. It is also demonstrated that there is minimal impact of pulsatile pressure of blood flow and variation of radial force on the degradation rate of the cBRS. Moreover, the lumen of cBRS implanted vessels were enlarged after 6 months, and significantly larger than the vessels implanted with metallic stent in 12 months.

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.

Relationship between Lp-PLA2 and in-stent restenosis after coronary stenting: a 3-year follow-up study

BACKGROUND AND AIMS

Coronary in-stent restenosis (ISR) is an important complication of percutaneous coronary intervention (PCI). However, the relationship between lipoprotein associated phospholipase A2 (Lp-PLA2) level and ISR after PCI is rarely reported. This study aims to explore the relationship between Lp-PLA2 and the occurrence of ISR at post-PCI and its predictive value for ISR.

METHODS AND RESULTS

Plasma Lp-PLA2 mass were measured in 847 patients planting 1262 stents and evaluated along with known risk indicators. One-year angiographic follow-up showed that baseline elevated Lp-PLA2 mass was strongly associated with early restenosis (95% CI = 1.062-3.050, P < 0.05). Beyond the first year, the occurrence of late restenosis (95% CI = 1.043-3.214, P < 0.05) was significantly larger in the elevated Lp-PLA2 group. Kaplan-Meier analysis after three-year clinical follow up suggested that Lp-PLA2 mass did add the positive effect on the occurrence of major adverse cardiovascular events (MACEs).

CONCLUSION

In conclusion, increased baseline plasma Lp-PLA2 predicts increased risks of re-stenosis and MACEs, which may be a novel biomarker for predicting ISR and MACEs.

Late neointimal volume reduction is observed following biodegradable polymer-based drug eluting stent in porcine model

BACKGROUND

The BP-SES has an abluminally applied biodegradable polymer that is fully resorbed after 3-4 months but may have longer-lasting effects. The aim of this study was to determine the long-term vascular response to the novel Ultimaster™ sirolimus-eluting stent (BP-SES).

METHODS

BP-SESs, everolimus-eluting stents (DP-EESs), and bare metal stents were implanted in 22 coronary arteries of 15 mini-swine. All animals underwent optical frequent domain imaging (OFDI) to assess neointimal volume and quality at either 1 (n = 7) or 3 (n = 8) months and at 9 (n = 15) months and were euthanized at 9 months. Stents were subsequently histologically investigated to analyze the vascular response and maturity of neointimal tissue according to cell density.

RESULTS

OFDI revealed greater regression in neointimal volume from 3 to 9 months with BP-SESs than with DP-EESs (-0.6 ± 0.5 mm2 vs. 0.00 ± 0.4 mm2, p = 0.07). Although there was no significant difference between BP-SESs and DP-EESs in the inflammation score (BMS, BP-SES, and DP-EES: 0.1 ± 0.1, 0.3 ± 0.4, and 0.4 ± 0.4, respectively; p < 0.0001) in histological analysis, BP-SESs showed slightly greater maturity than DP-EESs (1.8 ± 0.3, 1.7 ± 0.3, and 1.6 ± 0.3, p = 0.09).

CONCLUSIONS

While both BP-SESs and DP-EESs showed minimal inflammatory responses at 9 months, BP-SESs showed a trend for greater neointimal maturity and regression, which may be related to earlier completion of the vascular response.

Risk prediction of in-stent restenosis among patients with coronary drug-eluting stents: current clinical approaches and challenges

Introduction: In-stent restenosis (ISR) has been one of the biggest limitations to the success of percutaneous coronary intervention for the treatment of coronary artery disease (CAD). The introduction of drug-eluting stent (DES) was a revolution in the treatment of CAD because these devices drastically reduced ISR to very low levels (<5%). Subsequently, newer generation DES treatments have overcome the drawbacks of first-generation DES, i.e. delayed endothelialization, and late stent thrombosis. However, the issue of late ISR, including neoatherosclerosis after DES implantation especially in high-risk patients and complex lesions, still exists as a challenge to be overcome.Areas covered: We discuss the mechanisms of ISR development including neoatherosclerosis, past and current clinical status of ISR, and methods to predict and overcome this issue from pathological and clinical points of view.Expert opinion: The initial drawbacks of first-generation DES, such as delayed endothelial healing and subsequent risk of late stent thrombosis, have been improved upon by the current generation DES. To achieve better long-term clinical outcomes, further titration of drug-release and polymer degradation profile, strut thickness as well as material innovation are needed.

Intentional Stent Stenosis to Prevent Hyperperfusion Syndrome after Carotid Artery Stenting for Extremely High-Grade Stenosis

BACKGROUND AND PURPOSE

Intracranial hemorrhage due to hyperperfusion syndrome is a severe carotid artery stent placement complication of extremely high-grade stenosis, causing hemodynamic insufficiency. To prevent hyperperfusion syndrome, we attempted intentional residual stent stenosis and implemented "gentle" carotid artery stent placement, defined as carotid artery stent placement using a closed-cell stent coupled with slight balloon predilation, without balloon postdilation. Gradual stent expansion was expected. We investigated the incidence of hyperperfusion syndrome and long-term outcomes after gentle carotid artery stent placement.

MATERIALS AND METHODS

We included patients who underwent carotid artery stent placement for extremely high-grade stenosis from January 2015 to March 2019. We defined extremely high-grade stenosis as carotid stenosis with conventional angiographic "slow flow" and a reduced MCA signal intensity on MRA. A reduced MCA signal intensity was defined as MCA with a relative signal intensity of <0.9 in the ipsilateral compared with the contralateral MCA. We evaluated the stent diameter, CBF on SPECT, hyperperfusion syndrome, and intracranial hemorrhage. We defined hyperperfusion syndrome as a triad of ipsilateral headache, seizure, and hemiparesis.

RESULTS

Twenty-eight of the 191 patients met our inclusion criteria. After carotid artery stent placement, their median minimal stent diameter was 2.9 mm, which expanded to 3.9 mm at 4 months. Neither cerebral hyperperfusion syndrome nor intracranial hemorrhage occurred.

CONCLUSIONS

The gentle carotid artery stent placement strategy for intentional residual stent stenosis may prevent hyperperfusion syndrome in high-risk patients. Stents spontaneously dilated in 4 months.

Bench-Top Comparison of Three Different Types of Stents Used for Treatment of Intracranial Atherosclerotic Stenosis

Purpose

Four key bench-top tests, including trackability, conformability, wall-apposition, and bending stiffness, were performed to understand the mechanical characteristics in 3 different types of stents applicable for treatment of intracranial atherosclerotic stenosis: Balloon-expandable D⁺Storm, Pro-Kinetic Energy, and self-expandable Wingspan stents.

Materials and Methods

Trackability was assessed by measuring the tracking forces of each stent with its delivery systems. Conformability and wall apposition were quantified and analyzed using curved vessel models. A 3-point bending test was employed to evaluate bending stiffness.

Results

D⁺Storm showed the lowest tracking forces while the conformability of the Wingspan stent was superior to that of the tested stents. Pro-Kinetic Energy and D⁺Storm had better wall apposition in curved vessels than the Wingspan stent. Bending stiffness of the Wingspan stent was notably lower, whereas no significant differences were found between D⁺Storm and Energy. Pro-Kinetic Energy and D⁺Storm not only indicated lower gap ratios between the struts and the vessel wall but also maintained good wall apposition even in the curved model.

Conclusion

These bench-top measurements may provide clinicians with useful information in regard to selecting suitable stents for treatment of intracranial atherosclerotic stenosis.

Clinical expert consensus document on quantitative coronary angiography from the Japanese Association of Cardiovascular Intervention and Therapeutics

Quantitative coronary angiography (QCA) remains to play an important role in clinical trials and post-marketing surveillance related to the safety and efficacy of new PCI devices. In this document, the current standard methodology of QCA is summarized. In addition, its history, recent development and future perspectives are also reviewed.

Drug-Eluting Versus Bare-Metal Stent Implantation With or Without Cilostazol in the Treatment of the Superficial Femoral Artery

BACKGROUND

New-generation bare-metal nitinol (BNS) and drug-eluting stents have improved long-term outcomes in patients undergoing endovascular therapy for femoropopliteal lesions. Furthermore, cilostazol reduces in-stent restenosis (ISR) after first-generation BNS implantation for femoropopliteal lesions.

METHODS AND RESULTS

We studied 255 patients with femoropopliteal lesions treated at 25 cardiovascular centers. Patients were randomly assigned to the BNS group (Misago stent implantation without cilostazol), BNS with cilostazol group (Misago stent implantation with cilostazol), or drug-eluting stents group (Zilver PTX stent implantation without cilostazol). Primary end point was 1-year restenosis noted using duplex ultrasound (peak systolic velocity ratio, >2.0). Secondary end point was major adverse limb events (limb-related death, target lesion revascularization, major amputation, and major bleeding). During the 1-year follow-up, 12 patients (4.7%) died and 237 (92.9%) had relevant ultrasound findings. The 1-year ISR rate did not differ significantly among the BNS, BNS with cilostazol, and drug-eluting stents groups (28.4% versus 12.2% versus 21.0%; P=0.052). Although the 1-year ISR rate was significantly lower in the BNS with cilostazol group than in the BNS group, it was similar to that in the drug-eluting stents group ( P=0.16). Major adverse limb event was significantly higher in the BNS group (16.9% versus 6.5% versus 6.3%; P=0.034); however, target lesion revascularization and major bleeding were similar (9.7% versus 5.1% versus 3.6%; P=0.25, 4.8% versus 1.2% versus 2.4%; P=0.37, respectively).

CONCLUSIONS

Misago stent implantation with cilostazol showed a comparable 1-year ISR rate with Zilver PTX. Cilostazol reduced the 1-year ISR rate after endovascular therapy when used with new-generation BNS.

CLINICAL TRIAL REGISTRATION

URL: http://www.umin.ac.jp/ctr/ . Unique identifier: UMIN 000010071.

Efficacy Over Time With Drug-Eluting Stents in Saphenous Vein Graft Lesions

BACKGROUND

In the ISAR-CABG (Is Drug-Eluting-Stenting Associated with Improved Results in Coronary Artery Bypass Grafts?) trial, clinical outcomes at 1 year in patients undergoing treatment of saphenous vein graft lesions were superior with drug-eluting stents (DES) versus bare-metal stents.

OBJECTIVES

The authors compared outcomes between treatment groups at 5 years.

METHODS

Patients were randomized (1:1:1:3) to receive DES (either permanent-polymer paclitaxel-eluting stents, permanent-polymer sirolimus-eluting stents, or biodegradable-polymer sirolimus-eluting stents) or bare-metal stents. The primary endpoint was the combined incidence of death, myocardial infarction (MI), or target lesion revascularization (TLR). Secondary endpoints were the composite of death or MI and TLR.

RESULTS

A total of 610 patients were allocated to treatment with DES (n = 303) or bare-metal stents (n = 307). At 5 years, the primary endpoint occurred in 159 (55.5%) versus 157 (53.6%) patients in the DES and bare-metal stent groups, respectively (hazard ratio [HR]: 0.98; 95% confidence interval [CI]: 0.79 to 1.23; p = 0.89). There was interaction between treatment effect and time (p_interaction = 0.005), with a lower event rate in the DES group at 1 year (HR: 0.64; 95% CI: 0.44 to 0.94; p = 0.02) but a numerically higher rate between 1 and 5 years (HR: 1.24; 95% CI: 0.94 to 1.63; p = 0.13). Death or MI occurred in 93 (32.8%) versus 108 (36.6%) patients, respectively (HR: 0.85; 95% CI: 0.64 to 1.12; p = 0.24), without significant interaction between treatment effect and time (p_interaction = 0.57). TLR occurred in 84 (33.1%) versus 69 (25.5%) patients in the DES and bare-metal stent groups, respectively (HR: 1.20; 95% CI: 0.87 to 1.64; p = 0.27). There was interaction between treatment effect and time (p_interaction <0.001): TLR was significantly lower in the DES group at 1 year (HR: 0.49; 95% CI: 0.28 to 0.86; p = 0.01) but significantly higher thereafter (HR: 2.02; 95% CI: 1.32 to 3.08; p = 0.001).

CONCLUSIONS

In patients undergoing treatment of saphenous vein graft lesions, the advantage of DES over bare-metal stents demonstrated at 1 year was lost at 5 years due to higher attrition of efficacy in the DES group. (Efficacy Study of Drug-Eluting and Bare Metal Stents in Bypass Graft Lesions [ISAR-CABG]; NCT00611910).

Vessel Calcification as a Risk Factor for In-Stent Restenosis in Complex Femoropopliteal Lesions After Zilver PTX Paclitaxel-Coated Stent Placement

Purpose: To evaluate the effect of vessel calcification on in-stent restenosis (ISR) after drug-coated stent (DCS) placement in the femoropopliteal segment. Materials and Methods: A retrospective multicenter study was undertaken involving 220 consecutive symptomatic patients (mean age 73.1±8.3 years; 175 men) with femoropopliteal lesions in 230 limbs treated with the Zilver PTX DCS and having duplex surveillance after the endovascular procedures. Mean lesion length was 16.4±9.8 cm (range 2–40); there were 104 (45.2%) total occlusions and 68 (29.6%) in-stent restenoses (ISR). Twenty (8.7%) vessels had no runoff. The majority of lesions (148, 64.3%) were calcified according to the peripheral arterial calcium scoring system (PACSS). Primary patency was evaluated by duplex. Lesions were classified as either PACSS 0–2 (none or unilateral wall calcification) or PACSS 3 and 4 (bilateral wall calcification). Multivariate analysis was performed to identify variables associated with ISR; the results are given as the hazard ratio (HR) and 95% confidence interval (CI). Results: The 1-, 2-, and 5-year primary patency and freedom from clinically-driven target lesion revascularization estimates were 75.9%, 63.6%, and 45.0%, and 84.7%, 73.7%, and 54.2%, respectively. Major amputations were performed on 4 limbs during follow-up. In multivariate analysis, vessel calcification (adjusted HR 1.718, 95% CI 1.035 to 2.851, p=0.036) was significantly correlated with the occurrence of ISR, along with lesion length (adjusted HR 1.041, 95% CI 1.013 to 1.070, p=0.003), and cilostazol administration (adjusted HR 0.476, 95% CI 0.259 to 0.876, p=0.017). Conclusion: This study suggested that bilateral vessel wall calcification was an independent risk factor for ISR in complex femoropopliteal lesions after Zilver PTX DCS placement, along with lesion length; cilostazol administration had a protective effect.

The Predictors of Target Lesion Revascularization and Rate of In-Stent Restenosis in the Second-Generation Drug-Eluting Stent Era

Objectives

The aim of our study was to investigate the predictors of target lesion revascularization (TLR) and to compare the in-stent restenosis (ISR) progression rates of different 2nd-generation drug-eluting stents (DES).

Background

The predictors of early and late TLR after 2nd-generation DES implantation have not been fully evaluated.

Methods

We analyzed 944 stented lesions from 394 patients who had at least two serial follow-up angiograms, using quantitative coronary angiography (QCA) analysis. The study endpoints were TLR and the velocity of diameter stenosis (DS) progression.

Results

TLR occurred in 58 lesions (6.1%) during the first angiographic follow-up period and 23 de novo lesions (2.4%) during the following second interval. Independent predictors for early TLR were diabetes mellitus (DM) (HR 2.58, 95% CI 1.29–5.15, p=0.007), previous percutaneous coronary intervention (PCI) (HR 2.41, 95% CI 1.03–5.65, p=0.043), and postprocedure DS% (HR 1.08, 95% CI 1.05–1.11, p<0.001, per 1%), while predictors of late TLR were previous PCI (HR 9.43, 95% CI 2.58-34.52, p=0.001) and serum C-reactive protein (CRP) (HR 1.60, 95% CI 1.28-2.00, p<0.001). The ISR progression velocity (by DS%) was 12.1 ±21.0%/year and 3.7 ±10.1%/year during the first and second follow-up periods, respectively, which had no significant difference (p>0.05) between the four types of DESs.

Conclusions

Our data showed that predictors for TLR may be different at different time intervals. DM, pervious PCI, and postprocedure DS could predict early TLR, while previous PCI and CRP level could predict late TLR. Contemporary DESs had similar rates of ISR progression rates.

Trial Registration

This study was retrospectively registered and approved by the institutional review board of Seoul National University Hospital (no. 1801–138-918).

Serial Optical Coherence Tomography at Baseline, 7 Days, and 1, 3, 6 and 12 Months After Bioresorbable Scaffold Implantation in a Growing Porcine Model

BACKGROUND

Little is known about serial changes in lumen and device dimensions after bioresorbable scaffold implantation in a growing animal model. Methods and Results: ABSORB (n=14) or bare metal stents (ICROS amg [Abbott Vascular, Santa Clara, CA, USA], Winsen-Luhe, Germany; n=15) were implanted in the coronary arteries of domestic swine (a hybrid of Finnish-Norwegian Landrace swine) weighing 30-35 kg. Angiography and optical coherence tomography (OCT) were performed immediately after implantation and repeated at 7 days, 1, 3, 6 and 12 months after the index procedure. One month after implantation, mean lumen area decreased relative to baseline in both groups (relative area change from baseline, -41.4±15.6% for ABSORB vs. -20.9±18.6% for ICROS) while mean device area decreased only in the ABSORB group (relative area change: -11.1±9.4% vs. +0.14±7.95%, respectively). At 12 months, mean lumen area increased relative to baseline in both groups (relative area change from baseline, +55.6±22.4% vs. +32.3±83.6%, respectively) in accordance with the swine growth weighing up to 260-300 kg. Mean device area in the ICROS group remained stable whereas that in the ABSORB group began to increase between 3 and 6 months along with the vessel growth (relative area change: +107.8±25.7% vs. +0.14±7.95%).

CONCLUSIONS

In the growing porcine model, ABSORB was associated with greater extent of recoil 1 month after implantation compared with ICROS but demonstrated substantial adaptability to vessel growth in late phase.

Effectiveness and Safety of Compound Chinese Medicine plus Routine Western Medicine in In-Stent Restenosis: A Meta-Analysis and Systematic Review

Objective

To examine the effects and safety of oral compound Chinese medicine (CCM) plus routine western medicine (RWM) in in-stent restenosis (ISR).

Methods

Various electronic databases (CBM, CNKI, VIP, Wanfang, PubMed, EMBASE, and Cochrane Library) were searched until April 2017. The quality of the included studies was evaluated, and meta-analyses were performed using RevMan5.3 and STATA 12.0 software. Moreover, funnel plot and Egger's publication bias plots were analysed to identify publication bias and adverse reactions were reported. A sensitive analysis was carried out according to the quality score.

Results

In all, 40 RCTs involving 4536 patients were selected for this review. The pooled estimates of three studies showed that the benefit to the number of ISRs (NoR) was more substantial for CCM plus RWM than for RWM alone (RR 0.24, 95% CI 0.10 to 0.57, P = 0.001; I² = 0%, P = 0.81). The rate of ISR was significantly lower for CCM plus RWM than for the same RWM alone (RR 0.44, 95% CI 0.37 to 0.53, P < 0.00001; I² = 0%, P = 0.95). CCM plus RWM benefitted the rate of ISR when a CM placebo plus RWM was used as the control intervention (RR 0.34, 95% CI 0.20 to 0.57, P < 0.0001; I² = 0%, P = 0.95). The difference of adverse reactions was not significant. For secondary outcomes, the CCM plus RWM group did not reduce the rates of revascularization and cardiac death, but it did reduce the rate of recurrent angina over the results observed in the RWM alone group. In addition, funnel plot and Egger's publication bias plot indicated that there was publication bias. The association between the use of CCM plus RWM and RWM alone remained significant after the sensitivity analysis excluding studies with low quality score (quality score ⩽ 4) with a pooled RR of 0.41 (95% CI, 0.34–0.50).

Conclusion

Oral CCM plus RWM clearly benefitted patients with percutaneous coronary intervention (PCI) because it prevented and treated ISR better than was observed for either RWM alone or a CM placebo plus RWM.

Autoimmune Diseases May Increase Adverse Cardiovascular Events After Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

BACKGROUND

Outcomes of patients with autoimmune diseases after percutaneous coronary intervention (PCI), as compared to those without autoimmune disease, remain unclear.

METHODS

We searched Medline, EMBASE, and the Cochrane Library from their inception to 1 April 2017. All studies comparing the following outcomes of patients with and without autoimmune diseases after PCI were included: long-term mortality, major adverse cardiovascular events (MACE), repeat revascularisation, myocardial ischaemia or myocardial infarction (MI), restenosis, and in-hospital mortality. The Newcastle-Ottawa Quality Assessment Scale (NOS) and the quality assessment form of the Agency for Healthcare Research and Quality (USA) (AHRQ) were used for assessing the risk of bias, and the certainty of evidence was rated by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).

RESULTS

A total of 11 studies were included in our analysis. Compared with patients without autoimmune diseases, those with autoimmune diseases carried an increased risk of MACEs (relative risk (RR): 2.24, 95% confidence interval (CI): 1.20-4.16; heterogeneity: p=0.128, I²=56.9%), repeat revascularisation (RR: 1.66, 95% CI 95%: 1.01-2.72; heterogeneity: p=0.057, I²=65.1%), ischaemia or MI (RR: 2.80, 95% CI: 1.38-5.65; heterogeneity: p=0.871, I²=0.0%), and restenosis (RR: 2.06, 95% CI: 1.39-3.07; heterogeneity: p=0.665, I²=0.0%) during the one-year follow-up after PCI, and carried an increased risk of MACEs (RR: 1.10, 95% CI: 1.04-1.17) and death (RR: 1.38, 95% CI: 1.25-1.51) during the 11-year follow-up after PCI.

CONCLUSIONS

Evidence of very low quality showed that during the one-year follow-up period, patients with autoimmune diseases after PCI were more likely to experience MACEs, repeat revascularisation, myocardial ischaemia or MI, and restenosis. During the 11-year follow-up period, patients with autoimmune diseases after PCI were more likely to die. It is therefore important to watch for restenosis, repeat ischaemia or MI and other adverse events more carefully in patients with autoimmune diseases after PCI.

Failure mode and bimodal restenosis of drug-coated balloon in femoropopliteal intervention

BACKGROUND

Pattern of DCB restenosis and associated outcomes in facing complex femoropopliteal lesions remain uncertain.

METHODS

Data were retrospectively collected from dual centers in Taiwan on patients who underwent treatment with DCBs for femoropopliteal lesions between 2013 and 2016. The restenosis pattern was categorized by the index-treated length. Clinical outcomes and time to DCB restenosis were retrospectively analyzed. Cox proportional hazards model identified restenosis predictors.

RESULTS

We recruited a total of 164 patients (91 men; median age 73 years) into the final analysis. The mean lesion length was 204.0 ± 109.2 mm. Of them, 45% total occlusions, 28% severe calcification and 15% in-stent restenosis were treated. Fifty-five patients have DCB restenosis (28 focal and 27 diffuse-occlusive patterns) over a 55-month follow-up. The median restenosis time emerged as a bimodal pattern with a significant difference between the diffuse-occlusive and focal restenosis group (225 vs. 484 days, P = 0.01). The 1-year patency rate after reintervention for DCB restenosis also was different between both restenosis group (29% vs. 65%, P = 0.017). The anticipated timing of escape for diffuse-occlusive or focal restenosis was 687 and 1068 days, respectively. Independent factors were lesion length (P = 0.049) for diffuse-occlusive restenosis and lumen gain of the popliteal artery for focal restenosis (P = 0.034).

CONCLUSIONS

This study demonstrated time to DCB failure emerged as a bimodal pattern of distribution and associations of restenosis pattern to subsequent outcomes after the repeated intervention. Exemption from late catchup restenosis required 3-year observation instead of the 1-year mark for conventional treatment.

Current Management of In-Stent Restenosis

Despite the advent of the drug-eluting stents (DES) and improved stent design, in-stent restenosis (ISR) remains a challenging problem. The currently available options for treatment of ISR include angioplasty alone, repeat stenting with DES or drug-coated balloons. Several recent studies have compared the available options for treating ISR in an attempt to identify the preferred therapeutic strategy. In this review, we will discuss the currently available therapeutic strategies for the management of patients with ISR and the evidence supporting their use.

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.

Translation in cardiovascular stents and occluders: From biostable to fully degradable

Cardiovascular disease is a major cause of morbidity and mortality, especially in developed countries. Most academic research efforts in cardiovascular disease management focus on pharmacological interventions, or are concerned with discovering new disease markers for diagnosis and monitoring. Nonpharmacological interventions with therapeutic devices, conversely, are driven largely by novel materials and device design. Examples of such devices include coronary stents, heart valves, ventricular assist devices, and occluders for septal defects. Until recently, development of such devices remained largely with medical device companies. We trace the materials evolution story in two of these devices (stents and occluders), while also highlighting academic contributions, including our own, to the evolution story. Specifically, it addresses not only our successes, but also the challenges facing the translatability of concepts generated via academic research.

Restenosis of the Coronary Arteries: Past, Present, Future Directions

Restenosis is a pathologic response to vascular injury, characterized by neointimal hyperplasia and progressive narrowing of a stented vessel segment. Although advances in stent design have led to a dramatic reduction in the incidence of restenosis, it continues to represent the most common cause of target lesion failure following percutaneous coronary intervention. Efforts to maximize restenosis prevention, through careful consideration of modifiable risk factors and an individualized approach, are critical, as restenosis, once established, can be particularly difficult to treat. Novel approaches are on the horizon that have the potential to alter the natural history of this stubborn disease.

A new approach to improve the local compressive properties of PPDO self-expandable stent

The radial performance of bioabsorbable polymeric intravascular stents is extremely important in assessing the efficiency of these devices in expanding narrow lumen, reducing stent recoil, and recovering to their original states after suffering from pulsating pressure. However, these stents remain inferior to metallic stents. Several thermal treatment conditions (60°C, 80°C, and 100°C for 1h) were investigated to improve the characteristics of poly(p-dioxanone) (PPDO) self-expandable stents. The local compressive force, stiffness, and viscoelasticity of these stents were also evaluated. Wide-angle X-ray diffraction and different scanning calorimetry measurements were performed to evaluate the recrystalline and thermodynamic changes of molecular chains. The declining conformer entropy of PPDO monofilaments was examined via energy analysis. The untreated stents had compressive modules of 514.80±70.59mN/mm, which was much higher than those of 80°C and 100°C treated stents (332.35±66.08mN/mm and 394.31±64.71mN/mm, respectively). Nevertheless, 100°C annealing stents had less stress relaxation and prior elastic recovery rate of 82.32±3.43mN and 92.55±1.61%, respectively, showing a much better shape stability than untreated stents (139.51±16.67mN and 86.18±3.57%, respectively). These findings present important clinical implications in the stent manufacturing process and warrant further study to develop new bioabsorbable stents with outstanding clinical efficacy.

Long-term (8-10 years) outcomes after biodegradable polymer-coated biolimus-eluting stent implantation

OBJECTIVE

Efficacy and safety data on biodegradable polymer-coated biolimus-eluting stent (BP-BES) are currently limited to 5 years. We evaluated longer term (8-10 years) clinical and angiographic outcomes after BP-BES implantation.

METHODS

Between 2005 and 2008, 243 patients (301 lesions) underwent BP-BES implantation. The primary clinical outcome measure was defined as any target lesion revascularisation (TLR). Absolute serial angiographic studies without any concomitant TLR within 2 years after the procedure were performed in 55 patients (65 lesions) at postprocedure, mid-term (within 1 year), late term (between 1 and 2 years) and very late term (beyond 2 years).

RESULTS

The median follow-up duration was 9.4 years (IQR 8.2-10.2 years). The 8-year cumulative incidence of any TLR was 20.3%. The increase rate was approximately 7% per year in the first 2 years, but decelerated to approximately 1.2% per year beyond 2 years after the procedure. The minimal lumen diameter significantly decreased from postprocedure (2.63±0.44 mm) to mid-term (2.43±0.59 mm, p=0.002) and from late term (2.27±0.63 mm) to very late term (1.98±0.73 mm, p=0.002). The 8-year cumulative incidences of definite or probable stent thrombosis (ST) and major bleeding (Bleeding Academic Research Consortium (BARC) ≥3) were 0.5% and 12.0%, respectively. Definite ST was none within 10 years in the entire cohort.

CONCLUSIONS

The long-term clinical outcomes after BP-BES implantation were favourable, although angiographic late progression of luminal narrowing did not reach a plateau. The incidence of ST remained notably low, whereas that of major bleeding gradually increased.

Intracoronary Imaging in the Detection of Vulnerable Plaques

Coronary artery disease is the result of atherosclerotic changes to the coronary arterial wall, comprising endothelial dysfunction, vascular inflammation and deposition of lipid-rich macrophage foam cells. Certain high-risk atherosclerotic plaques are vulnerable to disruption, leading to rupture, thrombosis and the clinical sequelae of acute coronary syndrome. Though recognised as the gold standard for evaluating the presence, distribution and severity of atherosclerotic lesions, invasive coronary angiography is incapable of identifying non-stenotic, vulnerable plaques that are responsible for adverse cardiovascular events. The recognition of such limitations has impelled the development of intracoronary imaging technologies, including intravascular ultrasound, optical coherence tomography and near-infrared spectroscopy, which enable the detailed evaluation of the coronary wall and atherosclerotic plaques in clinical practice. This review discusses the present status of invasive imaging technologies; summarises up-to-date, evidence-based clinical guidelines; and addresses questions that remain unanswered with regard to the future of intracoronary plaque imaging.

Long-term (>3 Years) Clinical and Angiographic Outcomes of Coronary Multilink Stent Implantations: A Single Center Experience

The ACS Multilink (ML) stent is a novel second-generation stent. The largest amount of information available on the long-term outcome of coronary stenting is based on the use of Palmaz-Schatz stents. Fewer data exist on long-term follow-up results of ML coronary stents implantations. The authors present the long-term (>3 years) clinical and angiographic follow-up results of the ACS Multilink coronary stents implanted in their institution. From May 1996 to December 1997, 125 patients underwent 133 coronary ML stent implantations. Stented vessels were as follows: 49% left anterior descending artery, 31% right coronary artery, and 20% left circumflex coronary artery. Indications for stent implantations were elective in 64%, because of suboptimal result from percutaneous transluminal coronary angioplasty (PTCA) in 26%, and bailout from PTCA in 10% of patients. The mean reference diameter of stented vessels was 3.2 ±0.2 mm. The mean percentage stenosis was 80 ±11% and 3 ±5% before and after stent implantation, respectively. Long-term clinical follow-up was completed in 75% (80 men, mean age 53 ±10 years) of the patients (either by interview or phone), and angiographic follow-up (37 ±12 months) was completed in 58% of the patients. There were no baseline clinical or angiographic differences between those angiographically followed up and the remaining patients. Angiographic restenosis (>50% diameter stenosis) was detected in 22% of stents. Target lesion revascularization was 12%, nontarget lesion revascularization was 14% in angiographically followed up patients. During the follow-up period death and new myocardial infarction occurred in 12% and 6% of patients, respectively, and survival rate was 88%. This study provides long-term follow-up results of intracoronary Multilink stent implantations for native coronary artery lesions. These data show that clinical and angiographic benefits of ML stents are comparable to those of the first-generation stents, especially to the Palmaz-Schatz stents, of which results have been reported previously. A considerable rate of nontarget lesion revascularization occurs during the follow-up period.

The role of angiographic follow-up after percutaneous coronary intervention

In the early days of coronary angioplasty, follow-up coronary angiography was often performed to assess restenosis. Angiographic restenosis has been shown to be associated with worse clinical outcomes, though the exact causality has yet to be determined. Numerous studies have repeatedly demonstrated that routine follow-up coronary angiography increases the incidence of target lesion revascularization without a clear reduction in mortality or myocardial infarction. Despite the lack of proven benefit of angiographic follow-up, routine follow-up coronary angiography is still being performed in certain countries and facilities. There are several factors that might explain the lack of benefit of angiographic follow-up: 1) lower incidence of stent failure in the current drug-eluting stent era has attenuated the net clinical benefit of follow-up angiography. 2) Angiographic restenosis might not lead to myocardial ischemia. 3) Patients that do have functionally significant restenosis are often referred for coronary angiography due to clinical indications such as intractable angina. 4) Absence of restenosis at the time of follow-up angiography does not exclude future restenosis. The absence of proven benefit in unselected populations does not necessarily preclude the presence of benefit in selected population, and there may be a subgroup of patients who can benefit from angiographic follow-up such as those with a large myocardial ischemic territory or those at very high risk of restenosis. Until there is more clinical evidence with respect to follow-up angiography, the decision of whether or not to perform it routinely in selected high-risk population should entail an in-depth discussion with the patient.

Ozonetherapy protects from in-stent coronary neointimal proliferation. Role of redoxins

BACKGROUND

In-stent restenosis and poor re-endothelization usually follow percutaneous transluminal coronary angioplasty, even using drug-eluting stents, due to inflammation and oxidative stress. Medical ozone has antioxidant and anti-inflammatory properties and has not been evaluated in this context.

OBJECTIVES

To evaluate whether ozonotherapy might reduce restenosis following bare metal stents implantation in relation to the redoxin system in pigs.

METHODS

Twelve male Landrace pigs (51±9kg) underwent percutaneous transluminal circumflex coronary arteries bare metal stent implantation under heparine infusion and fluoroscopical guidance, using standard techniques. Pigs were randomized to ozonetherapy (n=6) or placebo (n=6) treatment. Before stenting (24h) and twice a week for 30days post-stenting, venous blood was collected, ozonized and reinfused. Same procedure was performed in placebo group except for ozonation. Both groups received antiplatelet treatment. Histopathology and immunohistochemistry studies were performed.

RESULTS

Severe inflammatory reaction and restenosis with increase in the immunohistochemical expression of thioredoxin-1 were observed in placebo group 30days after surgery. Oppositely, ozonetherapy drastically reduced inflammatory reaction and restenosis, and showed no increase in the Trx-1 immunohistochemical expression 30days after surgery. Immunolabeling for Prx-2 was negative in both groups. Ozonated autohemotherapy strikingly reduced restenosis 30days following PTCA with BMS implantation in pigs.

CONCLUSIONS

Stimulation of the redoxin system by ozone pretreatment might neutralize oxidative damage from the start and increase antioxidative buffering capacity post-injury, reducing further damage and so the demand for antioxidant enzymes. Our interpretation agrees with the ozone oxidative preconditioning mechanism, extensively investigated.

Pathology of Endovascular Stents

Contemporary endovascular stents are the product of an iterative design and development process that leverages evolving concepts in vascular biology and engineering. This article reviews how insights into vascular pathophysiology, materials science, and design mechanics drive stent design and explain modes of stent failure. Current knowledge of pathologic processes is providing a more complete picture of the factors mediating stent failure. Further evolution of endovascular stents includes bioresorbable platforms tailored to treat plaques acutely and to then disappear after lesion pacification. Ongoing refinement of stent technology will continue to require insights from pathology to understand adverse events, refine clinical protocols, and drive innovation.

Carotid and Vertebral Stenting: Preliminary Report

We report our initial experience of carotid and vertebral stenting. Three haemodynamically significant extra-cranial lesions (% diameter stenosis >70) in 3 clinically symptomatic patients were treated by stenting between March 1996 and September 1996.

Two lesions of the internal carotid arteries were ostial and in one case a subtotal stenosis and ostial lesion of the vertebral artery were observed.

All lesions looked more widely and smoothly dilated by stenting than by ordinary standard balloon angioplasty.

Stenting Treatment for Intra- and Extra-Cranial Atherosclerotic Diseases

The purpose of this study was to investigate the effect, safety and short-term outcome of stenting treatment for extra- and intra-cranial atherosclerotic diseases. Forty-one patients underwent stenting treatment using coronary and biliary stents.

Eleven patients had tubular or diffuse high-grade stenoses not amenable to standard balloon angioplasty involving intra-cranial arteries, while in thirty, extra-cranial arteries were involved. Stents were successfully implanted in 36 out of 41 lesions (88%) with 2% (1/41) of overall procedural morbidity rate. Procedural and clinical success rate of intra-cranial stent placement was 64% (7/11) and no complications occurred during or after intra-cranial stent placement: the morbidity rate was 0%. Hyperperfusion injury occurred in two patients after successful implantation of stents in subtotal occlusion of the internal carotid artery, and consequently the overall clinical success rate was 80% (33/41).

Restenosis occurred in four (12%) out of 33 patients who underwent six month follow-up arteriography. No ischemic attacks or stent-deformation occurred during follow-up after stenting treatment. For lesions not amenable to standard balloon angioplasty, endovascular stent placement seems to be a safe and effective treatment of modality.

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.

Use of intravascular ultrasound vs. optical coherence tomography for mechanism and patterns of in-stent restenosis among bare metal stents and drug eluting stents

This article is a perspective responses to the "Mechanisms and Patterns of Intravascular Ultrasound In-Stent Restenosis Among Bare Metal Stents and First- and Second-Generation Drug-Eluting Stents" by Goto et al., The above mentioned article outlines the use of intravascular ultrasound (IVUS) in visualizing the patterns and mechanisms of in-stent restenosis (ISR) post percutaneous coronary intervention (PCI). Although IVUS is an appropriate method of choice for this scenario, IVUS has certain limitations which can be overcome by using optical coherent tomography (OCT). OCT is not only able to overcome IVUS's limitations but is also able to provide additional information to enhance the understanding of in-stent restenotic lesions. This article also outlines the future directions for OCT both in clinical and investigation settings.

Very late ischemic complications in flow-diverter stents: a retrospective analysis of a single-center series

OBJECTIVE The authors evaluate the rate and discuss the pathomechanisms of very late (≥ 4-month) ischemic complications after flow-diverter stent (FDS) placement for intracranial aneurysms. METHODS The authors retrospectively reviewed the clinical data of the patients treated at Pitié-Salpêtrière Hospital between January 2010 and September 2014, who underwent FDS placement for intracranial aneurysm. The patients received dual-antiplatelet therapy (clopidogrel and aspirin) 5 days before and 3-6 months after the procedure and then aspirin alone for 6-9 months. An ischemic complication was defined as a sudden focal neurological deficit documented on diffusion-weighted images. RESULTS Eighty-six consecutive patients were included. Three (3.5%) patients treated with the Pipeline embolization device experienced a delayed acute ischemic stroke (2 cases of perforator/side-wall branch infarction and 1 case of thromboembolic stroke) with an average delay of 384 days (4 months, 20 months, and 13 months, respectively). The aneurysm locations were the left superior cerebellar artery, the right anterior choroid artery, and the left internal carotid artery (paraclinoid segment), respectively. The complications occurred after the patients had completed the antiaggregation protocol, except for Patient 1, who was receiving aspirin alone because of a spontaneous hematoma. At the acute phase, no in-stent thromboses were found on digital subtraction angiography. In Patient 2, the treated anterior choroid artery was occluded 20 months after the procedure. In Patient 3, a focal stenosis (approximately 40%) of the distal aspect of the FDS, probably caused by intimal hyperplasia, was seen. CONCLUSIONS Very late ischemic complications after FDS treatment were observed in 3.5% of the cases in the authors' series, some of which occurred as late as more than 1 year after placement.

Insulin Resistance as a Predictor of the Late Catch-up Phenomenon After Drug-Eluting Stent Implantation

BACKGROUND

Percutaneous coronary intervention (PCI) is an effective treatment for patients with ischemic heart disease. In particular, restenosis is suppressed after drug-eluting stent (DES) implantation. However, several problems remain. Previously, we reported neointimal proliferation after DES implantation, which was associated with insulin resistance (IR). The aim of the present study was to clarify whether IR is associated with mortality and major adverse cardiac and cerebrovascular events (MACCE) after 1st-generation DES implantation.

METHODS AND RESULTS

We researched the clinical records of 109 patients who had undergone elective PCI and DES implantation between May 2007 and December 2010. We segregated these patients according to the value of the homeostasis model assessment of IR (HOMA-IR) into Group P (n=63; HOMA-IR ≥2.5, positive) and Group N (n=46; HOMA-IR <2.5, negative), and examined the relationship between HOMA-IR and MACCE. The observation period was 7.4±1.6 years. There were no differences between the 2 groups in the occurrence of all-cause death, cardiac death, restenosis, myocardial infarction, stroke, heart failure, or stent thrombosis. However, the late catch-up phenomenon was significantly more common in Group P than in Group N (12.7% vs. 2.2% P=0.048).

CONCLUSIONS

IR is a useful predictor of the late catch-up phenomenon after DES implantation, and improvement of IR may help to prevent the phenomenon. (Circ J 2016; 80: 657-662).

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.