Stent thrombosis of drug eluting stent: Pathological perspective

Impact of acute coronary syndrome on early in-stent neoatherosclerosis as shown by optical coherence tomography

Background

Patients with acute coronary syndrome (ACS) have a higher risk of requiring target vessel revascularisation after percutaneous coronary intervention (PCI) than patients with stable angina. Neoatherosclerosis is a significant risk factor for very late stent thrombosis, and the presence of neoatherosclerosis is independently associated with major adverse cardiac events.

Aims

In this study, we used optical coherence tomography (OCT) to investigate the impact of ACS on neoatherosclerosis within 1 year after PCI.

Methods

We investigated 102 patients (122 lesions) who had undergone PCI using a second-generation drug-eluting stent (DES) from March 2017 to November 2020 and were followed up with OCT within 1 year. The patients were categorised into the ACS group or non-ACS group according to their clinical findings at the time of target lesion treatment. We used OCT to investigate the presence of neoatherosclerosis.

Results

The ACS group comprised 23 (22.5%) patients. There were no differences in the patients' clinical characteristics between the groups. The total stent length tended to be shorter in the ACS group than in the non-ACS group (24 mm vs 32 mm, respectively; p=0.09), but this difference was not statistically significant. The median duration from PCI was 290 days. Neoatherosclerosis was more frequent in ACS lesions (39% vs 4%; p<0.01), and implantation of a DES in ACS lesions was an independent predictor of neoatherosclerosis occurrence (odds ratio 9.70; p<0.01).

Conclusions

This observational study using OCT indicates that stenting for ACS lesions is associated with early in-stent neoatherosclerosis.

MiR-199a-5p Deficiency Promotes Artery Restenosis in Peripheral Artery Disease by Regulating ASMCs Function via Targeting HIF-1α and E2F3

BACKGROUND

Restenosis (RS) poses a significant concern, leading to recurrent ischemia and the potential for amputation following intraluminal angioplasty in the treatment of Peripheral Artery Disease (PAD). Through microRNA microarray analysis, the study detected a significant downregulation of miR-199a-5p within arterial smooth muscle cells (ASMCs) associated with RS.

OBJECTIVE

This research aims to explore the possible function and the underlying mechanisms of miR-199a-5p in the context of RS.

METHODS

Primary ASMCs were extracted from the femoral arteries of both healthy individuals and patients with PAD or RS. The expression levels of miR-199a-5p were assessed using both qRT-PCR and in situ hybridization techniques. To examine the impacts of miR-199a-5p, a series of experiments were performed, including flow cytometry, TUNEL assay, EdU assay, CCK8 assay, Transwell assay, and wound closure assay. A rat carotid balloon injury model was employed to elucidate the mechanism through which miR-199a-5p mitigated neointimal hyperplasia.

RESULTS

MiR-199a-5p exhibited downregulation in RS patients and was predominantly expressed within ASMCs. Elevated the expression of miR-199a-5p resulted in an inhibitory effect of proliferation and migration in ASMCs. Immunohistochemistry and a dual-luciferase reporter assay uncovered that RS exhibited elevated expression levels of both HIF-1α and E2F3, and they were identified as target genes regulated by miR-199a-5p. The co-transfection of lentiviruses carrying HIF-1α and E2F3 alongside miR-199a-5p further elucidated their role in the cellular responses mediated by miR-199a-5p. In vivo, the delivery of miR-199a-5p via lentivirus led to the mitigation of neointimal formation following angioplasty, achieved by targeting HIF-1α and E2F3.

CONCLUSION

MiR-199a-5p exhibits promise as a prospective therapeutic target for RS since it alleviates the condition by inhibiting the proliferation and migration of ASMCs via its regulation of HIF-1α and E2F3.

Natural History and Clinical Outcomes After ST-Segment Elevation Myocardial Infarction Without Stent Insertion

After restoration of coronary perfusion in patients presenting with ST-segment elevation myocardial infarction (STEMI), discrete severe stenotic coronary lesions are not always apparent. There remains ambiguity whether drug-eluting stent (DES) insertion or initial medical management is best practice. We sought to assess short-term clinical outcomes in patients presenting with STEMI without initial stent insertion. Patients who underwent percutaneous coronary intervention for STEMI between 2014 and 2020 were prospectively enrolled and assessed for inclusion. Patients presenting with in-stent restenosis or stent thrombosis, or who did not survive to hospital discharge were excluded. Of 13,871 patients presenting, 456 (3.3%) were treated without initial stenting. These patients were older than those treated with DES (66.1 ± 13.6 vs 62.3 ± 12.4 years, p <0.001), had higher rates of diabetes (23.5% vs 16.0%, p <0.001) and previous revascularization with either percutaneous coronary intervention (14.0% vs 7.3%, p <0.001) or coronary artery bypass graft (3.5% vs 1.8%, p = 0.008). Thirty-day mortality was elevated in patients treated without stenting compared to those receiving DES (4.2% vs 0.9%, p <0.001), as were rates of myocardial infarction (1.3% vs 0.5%, p = 0.026) and major adverse cardiac events (10.5% vs 2.4%, p <0.001). After propensity matching, a trend toward increased mortality remained (4.2% vs 2.0%, p = 0.055). In conclusion, a no-stenting initial strategy, compared with DES insertion, is associated with increased 30-day mortality in those presenting with STEMI without severe stenosis. These data suggest when appropriate, current-generation DES insertion should be undertaken.

In vitro biological responses of plasma nanocoatings for coronary stent applications

In-stent restenosis and thrombosis remain to be long-term challenges in coronary stenting procedures. The objective of this study was to evaluate the in vitro biological responses of trimethylsilane (TMS) plasma nanocoatings modified with NH3 /O2 (2:1 molar ratio) plasma post-treatment (TMS + NH3 /O2 nanocoatings) on cobalt chromium (CoCr) alloy L605 coupons, L605 stents, and 316L stainless steel (SS) stents. Surface properties of the plasma nanocoatings with up to 2-year aging time were characterized by wettability assessment and x-ray photoelectron spectroscopy (XPS). It was found that TMS + NH3 /O2 nanocoatings had a surface composition of 41.21 ± 1.06 at% oxygen, 31.90 ± 1.08 at% silicon, and 24.12 ± 1.7 at% carbon, and very small but essential amount of 2.77 ± 0.18 at% nitrogen. Surface chemical stability of the plasma coatings was noted with persistent O/Si atomic ratio of 1.292-1.413 and N/Si atomic ratio of ~0.087 through 2 years. The in vitro biological responses of plasma nanocoatings were studied by evaluating the cell proliferation and migration of porcine coronary artery endothelial cells (PCAECs) and smooth muscle cells (PCASMCs). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay results revealed that, after 7-day incubation, TMS + NH3 /O2 nanocoatings maintained a similar level of PCAEC proliferation while showing a decrease in the viability of PCASMCs by 73 ± 19% as compared with uncoated L605 surfaces. Cell co-culture of PCAECs and PCASMCs results showed that, the cell ratio of PCAEC/PCASMC on TMS + NH3 /O2 nanocoating surfaces was 1.5-fold higher than that on uncoated L605 surfaces, indicating enhanced selectivity for promoting PCAEC growth. Migration test showed comparable PCAEC migration distance for uncoated L605 and TMS + NH3 /O2 nanocoatings. In contrast, PCASMC migration distance was reduced nearly 8.5-fold on TMS + NH3 /O2 nanocoating surfaces as compared to the uncoated L605 surfaces. Platelet adhesion test using porcine whole blood showed lower adhered platelets distribution (by 70 ± 16%), reduced clotting attachment (by 54 ± 12%), and less platelet activation on TMS + NH3 /O2 nanocoating surfaces as compared with the uncoated L605 controls. It was further found that, under shear stress conditions of simulated blood flow, TMS + NH3 /O2 nanocoating significantly inhibited platelet adhesion compared to the uncoated 316L SS stents and TMS nanocoated 316L SS stents. These results indicate that TMS + NH3 /O2 nanocoatings are very promising in preventing both restenosis and thrombosis for coronary stent applications.

Smooth muscle differentiation of coronary intima in autopsy tissues after sirolimus-eluting stent implantation

BACKGROUND

In coronary atherosclerotic disease, the proliferation of intimal smooth muscle cells (SMCs) is regarded as beneficial with respect to stable and unstable plaques, but is thought detrimental in discussions on coronary stent restenosis. To resolve this discrepancy, we focused on the quality, not quantity, of intimal SMCs in coronary atherosclerotic disease.

METHODS

Autopsied coronary artery specimens from seven patients implanted with bare metal stents (BMS), three with paclitaxel-eluting stents (PES), and 10 with sirolimus (rapamycin)-eluting stents (SES) were immunostained for SMC markers. Cultured human coronary artery SMCs were also treated with sirolimus and paclitaxel.

RESULTS

Intimal SMC differentiation, estimated by the ratio of h-caldesmon+ cells to α-smooth muscle actin+ (α-SMA+) cells, was significantly increased whereas dedifferentiation, estimated from the ratio of fibroblast activation protein alpha (FAPα)+ cells to α-SMA+ cells, was significantly decreased, in tissues of SES compared with BMS cases. No difference in the degree of differentiation was found between PES and BMS cases or between the three groups in nonstented arteries used as controls. Correlation analyses for each field of view revealed a significant positive correlation between h-caldesmon and calponin staining but significant negative correlations with FAPα staining in α-SMA+ cells. Cultured SMCs were shorter (dedifferentiated) and showed an increased FAPα/α-SMA protein when treated with paclitaxel, whereas they became elongated (differentiated) and showed increased calponin/α-SMA proteins with sirolimus.

CONCLUSIONS

The SMCs of the coronary intima may differentiate after SES implantation. SMC differentiation may explain both the plaque stabilization and reduced risk of reintervention associated with SES.

Association between cancer history and second-generation drug-eluting stent thrombosis: insights from the REAL-ST registry

BACKGROUND

Cancer-associated thrombosis is a frequent complication of cancer; however, little evidence is available regarding the association between cancer history and coronary artery stent thrombosis (ST). We aimed to investigate the relationship between cancer history and second-generation drug-eluting stent thrombosis (G2-ST).

METHODS

From the REAL-ST (Retrospective Multicenter Registry of ST After First- and Second-Generation Drug-Eluting Stent Implantation) registry, this study evaluated 1265 patients (G2- ST cases, n = 253; controls, n = 1012) with cancer-related information available.

RESULTS

The prevalence of patients with cancer history was higher (12.3% vs. 8.5%, p = 0.065), and that of currently diagnosed and currently treated cancer was significantly higher in ST cases than controls (3.6% vs. 1.4%, p = 0.021; 3.2% vs. 1.3%, p = 0.037, respectively). Multivariable logistic regression analysis revealed that cancer history was associated with late ST (odds ratio [OR]: 2.80, 95% confidence intervals [CI]: 0.92-8.55, p = 0.071) and very late ST (OR: 2.40, 95% CI: 1.02-5.65, p = 0.046), but not with early ST (OR: 1.01, 95% CI: 0.51-2.00, p = 0.97). During the median follow-up period of 872 days after the index ST events, patients with cancer history showed a higher mortality than those without, among both ST cases (hazard ratio [HR]: 1.93, 95% CI: 1.06-3.51, p = 0.031) and controls (HR: 1.93, 95% CI: 1.09-3.40, p = 0.023).

CONCLUSION

A post hoc analysis of REAL-ST registry revealed that patients with G2-ST had a higher prevalence of currently diagnosed and currently treated cancer. Notably, cancer history was associated with the occurrence of late and very late ST, but not with early ST.

Genetic Backgrounds Associated With Stent Thrombosis: A Pilot Study From a Percutaneous Coronary Intervention Registry

Background

Stent thrombosis (ST) is a rare, yet devastating, complication following percutaneous coronary intervention (PCI), with poorly understood pathophysiologic characteristics and genetic backgrounds.

Objectives

The authors performed a genome-wide association study to identify the common genetic loci associated with early stent thrombosis (EST) and late/very late ST (LST/VLST) in a contemporary Japanese multicenter PCI registry.

Methods

Among 8,642 PCI patients included in the registry, 42 who experienced stent thrombosis [EST (n = 15) and LST/VLST (n = 27)] were included (mean age, 67.6 ± 10.8 years; and 88.1% men). We conducted a genome-wide association study using the BioBank Japan patient population as the control (control #1: acute coronary syndrome [n = 29,542] and control #2: effort angina [n = 8,900]) to identify significant single nucleotide polymorphisms (SNPs) and evaluate the performance of polygenic risk scores (PRSs) for predicting these conditions.

Results

We compared patients with EST with controls #1 and #2 and identified SNPs (rs565401593 and rs561634568) in NSD1, and patients with LST/VLST with controls #1 and #2 and identified SNPs (rs532623294 and rs199546342) in GRIN2A. PRS for LST/VLST showed high predictive performance (area under the curve 0.83 [95% CI: 0.76-0.89] and 0.83 [95% CI: 0.77-0.89]), whereas PRS for EST showed modest predictive performance (area under the curve 0.71 [95% CI: 0.58-0.85] and 0.72 [95% CI: 0.58-0.85]).

Conclusions

We identified different genetic predispositions between EST and LST/VLST and demonstrated that the incorporation of PRS may aid in risk prediction of this highly fatal event.

Pro-Healing Nanomatrix-Coated Stent Analysis in an In Vitro Vascular Double-Layer System and in a Rabbit Model

Cardiovascular stent technologies have significantly improved over time. However, their optimal performance remains limited by restenosis, thrombosis, inflammation, and delayed re-endothelialization. Current stent designs primarily target inhibition of neointimal proliferation but do not promote functional arterial healing (pro-healing) in order to restore normal vascular reactivity. The endothelial lining that does develop with current stents appears to have loose intracellular junctions. We have developed a pro-healing nanomatrix coating for stents that enhances healing while limiting neointimal proliferation. This builds on our prior work evaluating the effects of the pro-healing nanomatrix coating on cultures of vascular endothelial cells (ECs), smooth muscle cells (SMCs), monocytes, and platelets. However, when a stent is deployed in an artery, multiple vascular cell types interact, and their interactions affect stent performance. Thus, in our current study, an in vitro vascular double-layer (VDL) system was used to observe stent effects on communication between different vascular cell types. Additionally, we assessed the pro-healing ability and vascular cell interactions after stent deployment in the VDL system and in a rabbit model, evaluating the nanomatrix-coated stent compared to a commercial bare metal stent (BMS) and a drug eluting stent (DES). In vitro results indicated that, in a layered vascular structure, the pro-healing nanomatrix-coated stent could (1) improve endothelialization and endothelial functions, (2) regulate SMC phenotype to reduce SMC proliferation and migration, (3) suppress inflammation through a multifactorial manner, and (4) reduce foam cell formation, extracellular matrix remodeling, and calcification. Consistent with this, in vivo results demonstrated that, compared with commercial BMS and DES, this pro-healing nanomatrix-coated stent enhanced re-endothelialization with negligible restenosis, inflammation, or thrombosis. Thus, these findings indicate the unique pro-healing features of this nanomatrix stent coating with superior efficacy over commercial BMS and DES.

Comparison of 1-Month and 12-Month Vessel Responses Between the Polymer-Free Biolimus A9-Coated Stent and the Durable Polymer Everolimus-Eluting Stent

BACKGROUND

A polymer-free biolimus A9-coated stent (PF-BCS) may achieve better arterial healing than a durable polymer drug-eluting stent owing to its polymer-free feature.

METHODS AND RESULTS

This multicenter, prospective, observational study enrolled 105 patients (132 lesions) who underwent PF-BCS (51 patients, 71 lesions) or durable polymer everolimus-eluting stent (DP-EES, 54 patients, 61 lesions) implantation. Serial coronary angioscopy (CAS) and optical coherence tomography (OCT) examinations were performed at 1 and 12 months, and the serial vessel responses were compared between PF-BCS and DP-EES. The primary outcome measure was the incidence of subclinical intrastent thrombus on CAS. The secondary outcome measures were: adequate strut coverage (≥40 μm) on OCT and maximum yellow color grade on CAS. The incidence of thrombus was high at 1 month (100% vs. 93%, P=0.091), but decreased at 12 months (18% vs. 25%, P=0.56), without a significant difference between PF-BCS and DP-EES. The adequate strut coverage rate was significantly higher (84±14% vs. 69±22%, P<0.001) and yellow color was significantly less intense (P=0.012) at 12 months in PF-BCS than in DP-EES; however, they were not significantly different at 1 month (adequate strut coverage: 47±21% vs. 50±17%, P=0.40; yellow color: P=0.99).

CONCLUSIONS

Although the thrombogenicity of PF-BCS was similar to that of DP-EES, the adequate coverage and plaque stabilization rates of PF-BCS were superior to those of DP-EES at 12 months.

Early- and Middle-Phase Angioscopic Assessment of Arterial Healing Following Current Drug-Eluting Stent Implantation in Patients With Acute Coronary Syndrome

Background: Drug-eluting stents (DESs) have been widely used for the treatment of acute coronary syndrome (ACS). However, there are few reports on early- and middle-phase arterial repair after DES implantation in ACS patients. Methods and Results: Coronary angioscopy (CAS) findings covering the early and middle phases (mean [±SD] 4±1 and 10±2 months, respectively) of arterial healing after second- and later-generation DES placement between May 2009 and January 2020 were extracted from the Kansai Rosai Hospital Cardiovascular Center database. Neointimal coverage (NIC), yellow color intensity, and the incidence of thrombus adhesion were compared between ACS and chronic coronary syndrome (CCS) in the early (54 stents of 47 lesions, 38 ACS patients; 86 stents of 70 lesions, 52 CCS patients) and middle (179 stents of 154 lesions from 136 ACS patients; 459 stents of 374 lesions from 287 CCS patients) phases. In the early phase, NIC, the incidence of thrombus adhesion (ACS, 39.1%; CCS, 38.0%), and maximum yellow color grade were similar between the 2 groups. In the middle phase, although the maximum yellow color grade was significantly higher in the ACS group (P=0.013), NIC and the incidence of thrombus adhesion (ACS, 24.6%; CCS, 23.4%) were similar in the 2 groups. Conclusions: Arterial healing assessment with CAS showed that NIC and the incidence of thrombus adhesion after DES implantation were similar between ACS and CCS patients.

Analysis of risk factors for early stent thrombosis in the Chinese population: A multicenter restrospective study

BACKGROUND

The predictive scoring systems for early stent thrombosis (EST) remains blank in China. The study aims to evaluate the risk factors and conduct a prediction model of EST in the Chinese population.

METHODS

EST was defined as thrombosis that occurs within the first 30 days after primary percutaneous coronary intervention (PCI). Patients from ten Chinese hospitals diagnosed as stent thrombosis (ST) from January 2010 to December 2016 were retrospectively included as the study group. A control group (1 case:2 controls) was created by including patients without ST, major adverse cardiovascular events, or cerebrovascular events during follow-up. The present study evaluated 426 patients with single-vessel lesions and ultimately included 40 patients with EST and 80 control patients, who were included to identify factors that predicted EST and to develop a prediction scoring system. The other 171 patients without integrated 1:2 pair were used for external validation.

RESULTS

EST was independently associated with a low hemoglobin concentration (adjusted odds ratio [OR] 0.946, 95% confidence interval [95% CI] 0.901-0.993, P=0.026), a high pre-PCI Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score (OR 1.166, 95% CI 1.049-1.297, P=0.004), and a DAPT (DAPT) duration of <30 days (OR 28.033, 95% CI 5.302-272.834, P<0.001). The simple EST prediction score provided an area under the curve (AUC) of 0.854 (95% CI 0.777-0.932, P<0.001) with 70.0% sensitivity and 90.0% specificity, and 0.742 (95% CI 0.649-0.835, P<0.001) with 54.5% sensitivity and 81.0% specificity for external validation dataset.

CONCLUSIONS

EST may be independently associated with DAPT discontinuation within 30 days, a low hemoglobin concentration, and a high SYNTAX score. The scoring system also has a good ability to predict the risk of EST and may be useful in the clinical setting.

Two-Year Clinical Outcomes of Biodegradable Polymer vs. Durable Polymer Drug-Eluting Stent Implantation in Patients With End-Stage Renal Disease on Dialysis

Background: There are limited data comparing clinical outcomes between biodegradable polymer and durable polymer drug-eluting stents (BP-DES and DP-DES, respectively) in patients with end-stage renal disease (ESRD). Methods and Results: This study enrolled 229 ESRD patients who underwent successful percutaneous coronary intervention (PCI) for 400 lesions with 472 DES, with 2-year clinical outcomes compared between the BP-DES and DP-DES groups. The primary outcome measure was the incidence of target lesion revascularization (TLR), whereas secondary outcome measures were the occurrence of cardiac death (CD), myocardial infraction (MI), stent thrombosis (ST), target vessel revascularization (TVR), non-TVR, and major adverse cardiac events (MACE), defined as a composite of CD, MI, and TVR. Multivariate analysis was used to identify predictors of TLR occurrence. The 2-year incidence of TLR did not differ significantly between the BP-DES and DP-DES groups (P=0.274). In addition, there were no significant differences in the 2-year incidence of CD (P=0.144), MI (P=0.812), ST (P=0.241), TVR (P=0.434), non-TVR (P=0.375), or MACE (P=0.841) between the 2 groups. Multivariate analysis showed that diabetes (P=0.021) was independently associated with TLR occurrence. Conclusions: BP-DES and DP-DES had comparable safety and efficacy profiles over a 2-year follow-up period after PCI in ESRD patients.

Late endothelial progenitor cell-capture stents with CD146 antibody and nanostructure reduce in-stent restenosis and thrombosis

The restoration of damaged endothelium is promising to reduce side effects, including restenosis and thrombosis, in the stent treatment for vascular diseases. Current technologies based on drug delivery for these complications still do not satisfy patients due to invariant recurrence rate. Recently, even if one approach was applied to clinical trial to develop the firstly commercialized stent employing circulating endothelial progenitor cells (EPCs) in blood vessels, it resulted in failure in clinical trial. Based on instruction of the failed case, we designed an advanced EPC-capture stent covered with anti-CD146 antibody (Ab) immobilized silicone nanofilament (SiNf) for the highly efficient and specific capture of not early but late stage of EPCs. In vitro cell capture test demonstrates enhanced capture efficiency and adhesion morphology of late EPCs on the modified substrate. The modified substrates could capture 8 times more late EPCs and even 3 times more mesenchymal stem cells (MSCs) as compared to unmodified one. A porcine model with high similarity to human reproduced in vivo results ideally translated from in vitro cell capture results. As restenosis indicators, lumen area, neointimal rate and stenosis area for modified stents were reduced at the range of 30-60% as compared to those for bare metal stent (BMS). Fibrin score indicating thrombosis was lowered less than half as comparing to that on BMS. These inspiring results are attributed to ~2-fold increased endothelial coverage, determined by immuno-histological staining. Taken together, the CD146 Ab-armed nanofilamentous stent could show great performance in the reduction of thrombosis and restenosis through re-endothelialization due to highly efficient specific cell capture. STATEMENT OF SIGNIFICANCE: Stents have been developed from simple metal stents to functionalized stents for past decades. However, they have still risks to relapse the occlusion in stented arteries. In this paper, we describe the fabrication and optimization of cell capturing stents to maximize the effective re-endothelialization through the serial coating of silicone nanofilaments and anti-CD146 antibody. The nanofilaments increase the amount of coated antibodies and provide the anchoring points of circulating angiogenic cells for strong focal adhesion. We demonstrate high immobilizing ability of circulating angiogenic cells (endotheliali progenitor cells and mesenchymal stem cells) in vitro under similar shear stress to coronary arteries (15 dyne/cm²). Also, we show accelerating re-endothelialization and the efficient prevention of restenosis in porcine coronary arteries in vivo.

A paradox in sex-specific clinical outcomes after bioresorbable scaffold implantation: 2-year results from the AIDA trial

BACKGROUND

Females are underrepresented in clinical trials evaluating new stent technologies whilst results may differ between the sexes. Females are known to have smaller, more tortuous coronary arteries and have generally more comorbidities. On the other hand, they may have smaller plaque burden. This subgroup-analysis sought to assess sex-specific outcomes after Absorb bioresorbable vascular scaffold (BVS) or XIENCE everolimus-eluting stent (EES) implantation.

METHODS

The AIDA trial was an investigator-initiated, non-inferiority, all-comers trial, in which 1845 patients were randomly assigned to either Absorb BVS or XIENCE EES. Baseline clinical, angiography and procedural variables, as well as 2-year clinical outcomes were analyzed by sex and device modality.

RESULTS

Of the 1845 randomized patients, 475 (25.7%) were females. The 2-year rates of target vessel failure (TVF) with Absorb BVS versus XIENCE EES in females were 6.4% versus 10.6% (HR 0.59; 95% CI: 0.31-1.11; p = 0.10) and in males 12.7% versus 9.7% (HR 1.34; 95% CI: 0.98-1.85; p = 0.07). Males treated with Absorb BVS were at higher risk for TVF compared to females treated with Absorb BVS (HR 2.06; 95% CI 1.21-3.53; p = 0.007). Definite/probable device thrombosis occurred in females with Absorb BVS versus XIENCE EES in 1.6% versus 1.4% (HR 1.15; 95% CI: 0.26-5.12; p = 0.86) and in males 3.9% versus 0.7% (HR 5.55; 95% CI: 2.11-14.35; p < 0.001). A statistical significant interaction between sex and device was present for TVF (p = 0.02), but was not seen for definite/probable device thrombosis (p = 0.08).

CONCLUSIONS

In this subgroup analysis, Absorb BVS used in routine practice tends to result in better clinical outcomes in females compared to males.

Dutch multicenter experience using the STENTYS Xposition S self-apposing stent in complex coronary lesions

OBJECTIVES

The aim is to assess the experience in the Netherlands using the Xposition S self-apposing stent in complex coronary lesions in clinical practice.

BACKGROUND

Treatment of complex coronary lesions could be accompanied with stent sizing difficulties and complications, particularly due to vessel overdilation or stent underexpansion. The self-apposing feature of the Xposition S stent (STENTYS, Paris, France) supports good strut apposition in complex anatomies and allows for an increase in diameter after implantation.

METHODS

In this real-world registry, data from patients treated with Xposition S in four Dutch clinical sites were prospectively collected and analyzed. Any patient suitable for implantation with Xposition S according to current recommendations was enrolled. Primary endpoint was major adverse cardiac events (MACE) at 1 year.

RESULTS

Between 2015 and 2018, data from 251 patients were collected. Clinical presentation was an acute coronary syndrome in majority of the patients (76.9%). Main angiographic indications were lesions in aneurysmatic or ectatic vessels (32.3%), thrombus containing lesions (13.1%), and bifurcation/left main stenosis (10.4%). Most of the target lesions (TLs) were classified as AHA/ACC Type C (53.6%). Despite lesion complexity, device was successfully implanted at TL in 96.8%. MACE rate, reported on patients having completed 1-year follow-up (n = 203), was 6.6%, with low rate of definite/probable stent thrombosis (1.0%).

CONCLUSIONS

In clinical practice of several Dutch sites, STENTYS Xposition S showed good procedural results and low 1-year clinical events rate, despite complex coronary anatomy.

The blood compatibility challenge. Part 2: Protein adsorption phenomena governing blood reactivity

The adsorption of proteins is the initiating event in the processes occurring when blood contacts a "foreign" surface in a medical device, leading inevitably to thrombus formation. Knowledge of protein adsorption in this context has accumulated over many years but remains fragmentary and incomplete. Moreover, the significance and relevance of the information for blood compatibility are not entirely agreed upon in the biomaterials research community. In this review, protein adsorption from blood is discussed under the headings "agreed upon" and "not agreed upon or not known" with respect to: protein layer composition, effects on coagulation and complement activation, effects on platelet adhesion and activation, protein conformational change and denaturation, prevention of nonspecific protein adsorption, and controlling/tailoring the protein layer composition. STATEMENT OF SIGNIFICANCE: This paper is part 2 of a series of 4 reviews discussing the problem of biomaterial associated thrombogenicity. The objective was to highlight features of broad agreement and provide commentary on those aspects of the problem that were subject to dispute. We hope that future investigators will update these reviews as new scholarship resolves the uncertainties of today.

Implications of coronary artery bypass grafting and percutaneous coronary intervention on disease progression and the resulting changes to the physiology and pathology of the native coronary arteries

Myocardial revascularization can be achieved through 2 different methods: coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI). Clinical trials comparing PCI and CABG generally use the composite end points of death, stroke, myocardial infarction and target vessel revascularization to determine superiority. Other effects of these interventions, including the preservation of normal coronary physiology, the response of the coronary tree to stressors and the response of the vessel wall to the revascularization intervention, are not routinely considered, but these may have significant implications for patients in the medium and long term. For PCI, relatively small differences in clinical outcomes have been reported between bare metal and drug-eluting stents, and the latter seems to have inconsistent and somewhat unpredictable effects on the vascular biology of the coronary arteries. In coronary bypass, the use of arterial conduits is associated with superior clinical outcomes, better long-term patency and the preservation of essentially normal coronary function after intervention. This review assembles the clinical, physiological, angiographic and pathological literature currently available and attempts to provide a more complete picture of the effects of CABG and PCI on coronary arteries.

MiR-140-3p is Involved in In-Stent Restenosis by Targeting C-Myb and BCL-2 in Peripheral Artery Disease

Aim: In-Stent Restenosis (ISR) is the major reason for recurrent ischemia and amputation after endovascular treatment of Peripheral Artery Disease (PAD). Our previous study demonstrated that miR-140-3p is significantly down-regulated in PAD arteries. However, expression and function of miR-140-3p in ISR of human PAD are currently unclear.

The aim of this study is to determine the miR-140-3p expression and its regulative role in ISR of PAD.

Methods: The RNA level was determined by quantitative real-time polymerase chain Reaction (qRT-PCR) and in situ hybridization. Primary cultured ASMCs were isolated from human femoral arterial of the healthy donors or ISR patients. Cell proliferation was determined by Edu incorporation and CCK-8 assay. Apoptosis was determined by Annexin-V/PI Double-Staining assay and TUNEL assay. A rat carotid artery balloon angioplasty model was used to investigate the effect of miR-140-3p on restenosis.

Results: MiR-140-3p was significantly down-regulated in PAD and ISR arteries than normal arteries. Primary cultured ISR ASMCs exhibited elevated proliferation and down-regulated miR-140-3p than normal ASMCs. Transfection of miR-140-3p mimic attenuated PDGF-BB-induced proliferation in cultured ASMCs and induced apoptosis. Luciferase reporter assay indicated that miR-140-3p transfection significantly down-regulated C-Myb and BCL-2 in ISR ASMCs by targeting to their 3′-UTRs. MiR-140-3p transfection induced anti-proliferation and apoptosis in ASMCs, which were ameliorated by over-expression of C-Myb or BCL-2. Moreover, the animal study showed that miR-140-3p can reduce restenosis following angioplasty via targeting C-Myb and BCL-2.

Conclusions: The result suggests that miR-140-3p regulates ASMC function via targeting C-Myb and BCL-2 in the process of ISR in PAD. The novel findings may offer a hopeful therapeutic target for human PAD.

Stent thrombosis rates the first year and beyond with new- and old-generation drug-eluting stents compared to bare metal stents

Objectives

Old-generation drug-eluting coronary stents (o-DES) have despite being safe and effective been associated with an increased propensity of late stent thrombosis (ST). We evaluated ST rates in o-DES, new-generation DES (n-DES) and bare metal stents (BMS) the first year (< 1 year) and beyond 1 year (> 1 year).

Methods

We evaluated all implantations with BMS, o-DES (Cordis Cypher, Boston Scientific Taxus Liberté and Medtronic Endeavor) and n-DES in the Swedish coronary angiography and angioplasty registry (SCAAR) between 1 January 2007 and 8 January 2014 (n = 207 291). All cases of ST (n = 2 268) until 31 December 2014 were analyzed.

Results

The overall risk of ST was lower in both n-DES and o-DES compared with BMS up to 1 year (n-DES versus BMS: adjusted risk ratio (RR) 0.48 (0.41–0.58) and o-DES versus BMS: 0.56 (0.46–0.67), both p < 0.001). From 1 year after stent implantation and onward, the risk for ST was higher in o-DES compared with BMS [adjusted RR, 1.82 (1.47–2.25], p < 0.001). N-DES were associated with similar low ST rates as BMS from 1 year and onward [adjusted RR 1.21 (0.94–1.56), p = 0.135].

Conclusion

New-generation DES were associated with lower ST rates in comparison to BMS during the first-year post-stenting. After 1 year, n-DES and BMS were associated with similar ST rates.

Trial Registration

This study was a retrospective observational study and as such did not require clinical trial database registration.

Electronic supplementary material

The online version of this article (10.1007/s00392-018-1252-0) contains supplementary material, which is available to authorized users.

Acute Coronary Stent Thrombosis in Modern Era: Etiology, Treatment, and Prognosis

Acute stent thrombosis (AST) is a rare but life-threatening complication of coronary artery stenting. AST remains a challenging task for cardiologists, despite the application of modern procedural techniques and dual-antiplatelet therapy strategies as well as improved understanding of the underlying pathophysiology. This review focuses on the prevalence, risk factors, prognosis, multiple potential underlying pathogenesis, knowledge gaps, and recommends diagnosis and individualized management strategies of AST.

Heterogeneous Intravascular Ultrasound Findings of Stent Thrombosis

Objective The underlying mechanisms of stent thrombosis are not completely understood. Methods We experienced 12 definite stent thrombosis cases (1 early, 1 late, and 10 very late) at our hospital from July 2011 to April 2016 and evaluated the possible causes of stent thrombosis by intravascular ultrasound (IVUS). Results Five different potential morphological causes of stent thrombosis (neoatherosclerosis, stent malapposition, stent fracture, edge dissection, and stent underexpansion) were detected by IVUS in 10 cases (83.3%); in 1 of the remaining 2 cases, the discontinuation of antithrombotic drugs resulted in early stent thrombosis without abnormal IVUS findings. Of the 12 stent thrombosis cases, 4 occurred at a bare-metal stent (average time from stent implantation, 106 months); in all 12, significant neointimal hyperplasia was observed on IVUS, and 2 had plaque ruptures at an in-stent or proximal reference. Malapposed stent struts were observed in three very-late stent thromboses, and all of these underwent sirolimus-eluting stent implantation. Stent thrombosis due to mechanical (stent fracture) or procedure-related complications (edge dissection and stent underexpansion) was observed in three cases. Conclusion In patients with stent thrombosis, heterogeneous findings were observed in IVUS. This IVUS case series illustrates the possible mechanisms of stent thrombosis.

Visualizing polymeric bioresorbable scaffolds with three-dimensional image reconstruction using contrast-enhanced micro-computed tomography

There are no previous studies showing how to visualize polymeric bioresorbable scaffolds (BRSs) by micro-computed tomography (mCT). There are no previous studies showing how to visualize polymeric bioresorbable scaffolds (BRSs) by micro-computed tomography (mCT). This study aimed to explore the feasibility of detecting polymeric BRS with 3-dimensional reconstruction of BRS images by contrast-enhanced mCT and to determine the optimal imaging settings. BRSs, made of poly-L-lactic acid (PLLA), were implanted in coronary bifurcation models. Five treatments were conducted to examine an optimal condition for imaging BRSs: Baseline treatment, samples were filled with normal saline and scanned with mCT immediately; Treatment-1, -2, -3 and -4, samples were filled with contrast medium and scanned with mCT immediately and 1, 2 and 3 h thereafter, corresponding to soaking time of contrast medium of 0, 1, 2 and 3 h. Compared to Baseline, mCT scanning completely discriminate the scaffold struts from the vascular lumen immediately after filling the samples with contrast agent but not from the vascular wall until the contrast agent soaking time was more than 2 h (Treatment-3 and -4). By setting 10-15 HU as a cut-point of CT values, the scaffold strut detectable rate at Baseline and Teatment-1, -2, -3 and -4 were 1.23 ± 0.31%, 1.65 ± 0.26%, 58.14 ± 12.84%, 97.97 ± 1.43% and 98.90 ± 0.38%, respectively (Treatment-3 vs. Treatment-2, p < 0.01); meanwhile, the success rate of 3D BRS reconstruction with high quality images at Baseline and Teatment-1, -2, -3 and -4 were 1.23%, 1.65%, 58.14%, 97.97% and 98.90%, respectively (Treatment-3 vs. Treatment-2, p < 0.01). In conclusions, reconstruction of 3D BRS images is technically feasible by contrast-enhanced mCT and soaking time of contrast agent for more than 2 h is necessary for complete separation of scaffold struts from the surrounding structures in the phantom samples.

Comparison of Vascular Responses Following New-Generation Biodegradable and Durable Polymer-Based Drug-Eluting Stent Implantation in an Atherosclerotic Rabbit Iliac Artery Model

Background

Incomplete endothelialization is the primary substrate of late stent thrombosis; however, recent reports have revealed that abnormal vascular responses are also responsible for the occurrence of late stent failure. The aim of the current study was to assess vascular response following deployment of biodegradable polymer‐based Synergy (Boston Scientific) and Nobori (Terumo) drug‐eluting stents and the durable polymer‐based Resolute Integrity stent (Medtronic) in an atherosclerotic rabbit iliac artery model.

Methods and Results

A total of 24 rabbits were fed an atherogenic diet, and then a balloon injury was used to induce atheroma formation. Synergy, Nobori, and Resolute Integrity stents were randomly implanted in iliac arteries. Animals were euthanized at 28 days for scanning electron microscopic evaluation and at 90 days for histological analysis. The percentage of uncovered strut area at 28 days was lowest with Synergy, followed by Resolute Integrity, and was significantly higher with Nobori stents (Synergy 1.1±2.2%, Resolute Integrity 2.0±3.9%, Nobori 4.6±3.0%; P<0.001). At 90 days, inflammation score was lowest for Synergy (0.27±0.45), followed by Nobori (0.62±0.59), and was highest for Resolute Integrity (0.89±0.46, P<0.001). Foamy macrophage infiltration within neointima (ie, neoatherosclerosis) was significantly less with Synergy (0.62±0.82) compared with Nobori (0.85±0.74) and Resolute Integrity (1.39±1.32; P=0.034).

Conclusions

The biodegradable polymer‐coated thin‐strut Synergy drug‐eluting stent showed the fastest stent strut neointimal coverage and the lowest incidence of neoatherosclerosis in the current animal model.

Optical Coherence Tomography of De Novo Lesions and In-Stent Restenosis in Coronary Saphenous Vein Grafts (OCTOPUS Study)

BACKGROUND

The OCTOPUS registry prospectively evaluates the procedural and long-term outcomes of saphenous vein graft (SVG) PCI. The current study assessed the morphology of de novo lesions and in-stent restenosis (ISR) in patients undergoing PCI of SVG.

METHODS AND RESULTS

Optical coherence tomography (OCT) of SVG lesions in consecutive patients presenting with stable CAD and ACS was carried out. Thirty-nine patients (32 de novo and 10 ISR lesions) were included in the registry. ISR occurred in 5 BMS and 5 DES. There were no differences in the presence of plaque rupture and thrombus between de novo lesions and ISR. Lipid-rich tissue was identified in both de novo lesions and in ISR (75% vs. 50%, P=0.071) with a higher prevalence in BMS than in DES (23% vs. 7.5%; P=0.048). Calcific de novo lesions were detected in older grafts as compared with non-calcific atheromas (159±57 vs. 90±62 months after CABG, P=0.001). Heterogeneous neointima was found only in ISR (70% vs. 0, P<0.001) and was observed with similar frequency in both BMS and DES (24% vs. 30%, P=0.657). ISR was detected earlier in DES than BMS (median, 50 months; IQR, 18-96 months vs. 27 months; IQR, 13-29 months, P<0.001).

CONCLUSIONS

OCT-based characteristics of de novo and ISR lesions in SVG were similar except for heterogeneous tissue, which was observed only in ISR. (Circ J 2016; 80: 1804-1811).

Potential mechanisms of in-stent occlusion in the femoropopliteal artery: an angioscopic assessment

Although stent implantation has become widespread for the treatment of patients with peripheral artery disease with femoropopliteal (FP) lesions, in-stent restenosis, especially in-stent occlusion (ISO), remains as a major concern for refractory recurrence. Furthermore, the mechanisms of ISO in FP lesions have not been well elucidated. We performed angioscopy for 6 lesions (bare-metal stent: 3, drug-eluting stent: 3) from 5 patients (mean age 74 ± 10 years, male 40 %) with ISO in the FP artery immediately after wire-passing or thrombus aspiration. The presence of thrombus as well as the presence and location of organic stenosis were evaluated. Median duration from stent implantation to angioscopic evaluation was 1099.5 (514.5-2272.5) days, while the duration from recurrence of symptoms to angioscopic evaluation was 45 (5.75-60) days. Mixed thrombi were observed in all stents. Organic stenosis was detected at the proximal edge of the stents in 5 lesions. Organic stenosis was observed at the overlapping segment of the stent in one lesion. The distal edge of the stents could be evaluated in 3 lesions, and all of them showed organic stenosis at the site. Mixed thrombi and organic stenosis were observed in all stents. Partial development of organic stenosis in a stent followed by thrombus formation may be the potential mechanism of the development of ISO in the FP artery though the sample size of this study was small and it had no serial angioscopic data so that we should consider it as preliminary one at best.

Nitinol-Based Nanotubular Arrays with Controlled Diameters Upregulate Human Vascular Cell ECM Production

Current approaches to reducing restenosis do not balance the reduction of vascular smooth muscle cell proliferation with the increase in the healing of the endothelium. Building on our previous work, we present our study on the effects of Nitinol-based nanotubular coatings with different nanotube diameters on the reduction of restenosis. Here, we demonstrate that the nanotubular coatings reduced primary human aortic smooth muscle cell (HASMC) proliferation and increased the migration (by more than 4 times), collagen (by 2-3 times per cell) and elastin (by 5-8 times per cell) production of primary human aortic endothelial cells (HAEC). Furthermore, a significant increase in elastin and soluble collagen production of HAEC was observed with an increase in nanotube diameter. Our findings suggest that nanotubes-coated Nitinol may provide a surface conducive for HAEC reendothelialization while reducing the proliferation of HASMC.

Clinical outcome of drug-eluting versus bare-metal stents in patients with calcified coronary lesions: a meta-analysis

BACKGROUND

The relative safety and efficacy of drug-eluting stents (DES) versus bare-metal stents (BMS) in patients with calcified coronary lesions is still debated.

AIMS

To evaluate clinical outcome of DES versus BMS in patients with calcified coronary lesions using a meta-analysis of the current literature.

METHODS

We performed a systematic literature search using Medline, Embase, Cochrane and several other databases. Randomised controlled trials, prospective and retrospective cohort studies with a mean follow-up period >6 months were included. Primary efficacy was target lesions revascularisation (TLR) and primary end-point for safety was stent thrombosis. Secondary end-points were cardiac death and recurrent myocardial infarction (MI).

RESULTS

Five trials were included in the meta-analysis, including 2440 patients (1230 in the DES group, 1210 in the BMS group). TLR was significantly lower in patients treated with DES as compared with patients treated with BMS (8.5% vs 16.0%; odds ratio (OR) = 0.50; 95% confidence interval (CI) 0.38-0.65; P < 0.00001). There were no significant differences in the incidence of stent thrombosis (0.9% vs 0.3%; OR = 2.01; 95% CI 0.34-11.88; P = 0.44), cardiac death (3.3% vs 4.2%; OR = 0.81; 95% CI 0.50-1.30; P = 0.38) and recurrent MI (5.0% vs 5.2%; OR = 0.99; 95% CI, 0.66-1.49; P = 0.97) between the two groups. Subgroup analysis by the sample size and follow-up duration showed that the associations were similar between DES versus BMS.

CONCLUSIONS

DES significantly reduces TLR rates as compared with BMS in patients with calcified coronary lesions, with non-significant differences in terms of stent thrombosis, cardiac death and MI.

Prevention of stent thrombosis: challenges and solutions

Stent thrombosis is an uncommon but serious complication which carries with it significant mortality and morbidity. This review analyzes the entity of stent thrombosis from a historical and clinical perspective, and chronicles the evolution of this condition through the various generations of stent development, from bare metal to first-generation, second-generation, and third-generation drug-eluting stents. It also delineates the specific risk factors associated with stent thrombosis and comprehensively examines the literature related to each of these risks. Finally, it highlights the preventative strategies that can be garnered from the existing data, and concludes that a multifactorial approach is necessary to combat the occurrence of stent thrombosis, with higher risk groups, such as patients with ST segment elevation myocardial infarction, meriting further research.

Comparison of zotarolimus- and everolimus-eluting stents in patients with ST-elevation myocardial infarction and chronic kidney disease undergoing primary percutaneous coronary intervention

BACKGROUND

Chronic kidney disease (CKD) is associated with poor outcomes after percutaneous coronary intervention (PCI). The aim of the study was to compare zotarolimus- and everolimus-eluting stents used during primary PCI in patients with acute myocardial infarction (AMI) and CKD.

METHODS

We selected 854 consecutive ST-elevation MI patients with CKD (estimated glomerular filtration rate <60 mL/min/1.73 m(2)) undergoing primary PCI who were followed up for 12 months. They were divided into two groups based on type of stents implanted: (1) zotarolimus-eluting stent (ZES) and (2) everolimus-eluting stent (EES). The study end point was the 12-month major adverse cardiac events (MACE) which included all-cause death, non-fatal MI, target lesion revascularization (TLR), and target vessel revascularization (TVR).

RESULTS

The average number of stents used per vessel was 1.4 ± 0.7. A total of 433 patients received ZES and 421 patients received EES. There was no significant difference in the incidence of 12-month MI, TLR, or TVR. All-cause death was found to be borderline significant between two groups (2.8% in ZES vs 0.9% in EES, p=0.05). The incidence of 12-month MACE in ZES and EES was 5.7% and 2.6% respectively, p=0.022. Stent thrombosis did not differ between groups (p=0.677). Kaplan-Meier analysis did not show significant difference for 12-month MACE-free survival between groups (log-rank p=0.158). It remained the same even after propensity adjustment for multiple confounders in Cox model (p=0.326).

CONCLUSIONS

Implantation of ZES or EES provided comparable clinical outcomes with similar risk of 12-month MACE and death in STEMI patients with CKD undergoing primary PCI.

A case of in-stent neoatherosclerosis 10 years after carotid artery stent implantation: observation with optical coherence tomography and plaque histological findings

We report a patient's case of slow progressive in-stent restenosis 10 years after bare-metal stent implantation to his carotid artery. We treated the patient with an additional stent placement under a distal filter protection device. Optical coherence tomographic assessment and plaque histology during the carotid artery stenting (CAS) revealed atheromatous change at in-stent neointima, which contained lipid-rich plaque and calcification deposits. These findings suggest that in-stent neoatherosclerosis may play an important role in the pathogenesis of very late stent restenosis after CAS.

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.

Comparison of clinical outcomes between octogenarians and non-octogenarians with acute myocardial infarction in the drug-eluting stent era: analysis of the Korean Acute Myocardial Infarction Registry

BACKGROUND AND PURPOSE

Octogenarians (age ≥ 80 years) with coronary artery disease constitute a high-risk group. However, octogenarian patients with acute myocardial infarction (AMI) in the drug-eluting stents (DES) era have not been widely reported. We aimed to identify clinical outcomes in octogenarian compared with non-octogenarian AMI patients.

METHODS AND SUBJECTS

We retrospectively analyzed 9877 patients who underwent percutaneous coronary intervention (PCI) with drug-eluting stents (DES) and who were enrolled in the Korean Acute Myocardial Infarction Registry (KAMIR). They were divided into 2 groups, octogenarians (n=1494) and non-octogenarians (n=8383), in order to compare the incidence of 1-year all-cause death and 1-year major adverse cardiac events (MACE), where MACE included all-cause death, recurrent myocardial infarction, target vessel revascularization (TVR), target lesion revascularization (TLR), and coronary artery bypass grafting (CABG).

RESULTS

The clinical status was significantly inferior in octogenarians compared to non-octogenarians: Killip class ≥ II (34.8% vs. 22.5%, p<0.001), multivessel disease (65.8% vs. 53.7%, p<0.001). Rates of 1-year all-cause death were significantly higher in octogenarians than in non-octogenarians (22.3% vs. 6.5%, p<0.001). However, the rates of 1-year recurrent myocardial infarction (1.3% vs. 0.9%, p=0.68), TLR (2.4% vs. 3.1%, p=0.69), TVR (3.6% vs. 4.3%, p=0.96), and CABG (0.9% vs. 0.9%, p=0.76) did not differ significantly between the 2 groups.

CONCLUSIONS

Octogenarian AMI patients have higher rates of mortality and MACE even in the DES era. According to KAMIR subgroup analysis, the TLR/TVR rates in octogenarians were comparable to those in non-octogenarian AMI patients.

Outcome of prolonged balloon inflation for the management of coronary perforation

BACKGROUND

Coronary perforation (CP) is a rare, sometimes lethal complication of percutaneous coronary intervention (PCI).

OBJECTIVES

The purpose of this study was to review the cases of CP and to investigate the management after CP.

METHODS

A total of 3469 PCIs were performed in our institution from April 1999 to April 2008. All CP cases were identified from our computerized database.

RESULTS

Thirty patients were identified as having CP (0.86%). According to the Ellis classification, we determined the grade of perforation as type I in 17 cases (56%), type II in 2 cases (7%), and type III in 11 cases (37%). Most CPs were caused by wires (53%), while balloons, stents, and atherectomy devices were responsible for 7%, 37%, and 3%, respectively. Wire caused only 1 case of type III CP (6%), while stent caused 9 type III CPs (82%, p<0.01). Four patients (36%) with type III CP required urgent coronary artery bypass graft surgery (CABG), while no patient with type I/II CP required it (p<0.01). Prolonged balloon inflations were effective for 8 cases out of 11 stent CPs, however, the ballooning duration was significantly longer than that in wire and balloon CP (44±37min vs. 21±13min, p<0.05).

CONCLUSIONS

Stent CP often causes type III CP and one third of type III CP required urgent CABG. Although stent CP required longer balloon inflations for the management, prolonged balloon inflation might be useful for the management even in the stent CP.

Pharmacotherapeutic Considerations for the Use of Prasugrel and Ticagrelor to Reduce Stent Thrombosis in Patients With Acute Coronary Syndrome

Despite the improvement in stent technology, stent thrombosis (ST), a potentially catastrophic event, still occurs. Among several risk factors for ST, high on-treatment platelet reactivity to clopidogrel has been demonstrated to play a role, occurring in about one-third of the patients. In order to overcome this limitation, prasugrel and ticagrelor, newer P2Y12 inhibitors, have been developed and approved for clinical use. Two large clinical trials, TRial to assess Improvement in Therapeutic Outcomes by optimizing platelet inhibitioN with prasugrel-thrombolysis in myocardial infarction (TRITON-TIMI) 38 and Study of Platelet Inhibition and Patient Outcomes (PLATO), evaluated these drugs in patients with acute coronary syndrome (ACS), showing a significant improvement in efficacy end points (including a prominent reduction in ST occurrence) compared to clopidogrel. In contrast, the TRILOGY ACS trial found no benefit with prasugrel compared to clopidogrel in patients with medically treated ACS. The aim of this review is to consider decision-making strategies between prasugrel and ticagrelor in daily clinical practice.

Nickel-free stainless steel avoids neointima formation following coronary stent implantation

SUS316L stainless steel and cobalt-chromium and platinum-chromium alloys are widely used platforms for coronary stents. These alloys also contain nickel (Ni), which reportedly induces allergic reactions in some subjects and is known to have various cellular effects. The effects of Ni on neointima formation after stent implantation remain unknown, however. We developed coronary stents made of Ni-free high-nitrogen austenitic stainless steel prepared using a N2-gas pressurized electroslag remelting (P-ESR) process. Neointima formation and inflammatory responses following stent implantation in porcine coronary arteries were then compared between the Ni-free and SUS316L stainless steel stents. We found significantly less neointima formation and inflammation in arteries implanted with Ni-free stents, as compared to SUS316L stents. Notably, Ni2+ was eluted into the medium from SUS316L but not from Ni-free stainless steel. Mechanistically, Ni2+ increased levels of hypoxia inducible factor protein-1α (HIF-1α) and its target genes in cultured smooth muscle cells. HIF-1α and their target gene levels were also increased in the vascular wall at SUS316L stent sites but not at Ni-free stent sites. The Ni-free stainless steel coronary stent reduces neointima formation, in part by avoiding activation of inflammatory processes via the Ni-HIF pathway. The Ni-free-stainless steel stent is a promising new coronary stent platform.

Long-term efficacy of sirolimus-eluting stent for small vessel disease--subanalysis of Cypher Stent Japan Post-Marketing Surveillance Registry

BACKGROUND

Percutaneous coronary intervention for lesions with small vessel diameter may have high event rates. Although drug-eluting stents reduce the risk of restenosis, the long-term efficacy of drug-eluting stent implantation in small vessels is unclear.

METHODS AND RESULTS

We reviewed the data of Cypher Stent Japan Post-Marketing Surveillance Registry including 2356 lesions of 1959 patients, and retrospectively investigated the angiographic outcomes at 8 months, and the clinical outcomes at 1800 days after sirolimus-eluting stent (SES) implantation in vessels with diameter less than 2.5mm (small vessel group) compared to that with diameter of 2.5mm or more (non-small vessel group). The rate of major adverse cardiac events (MACE) at 1800 days was slightly higher in the small vessel group than in the non-small vessel group, but not statistically significant (24.4% vs 21.0%, p=0.086). The rate of target lesion revascularization was higher in the small vessel group than in the non-small vessel group (10.2% vs 6.4%, p=0.004). The rate of stent thrombosis was almost the same in the two groups. Multivariate Cox hazard model analysis revealed that a vessel diameter less than 2.5mm was not an independent risk factor for MACE.

CONCLUSION

SES implantation for vessels with diameter less than 2.5mm is safe and provides good long-term outcomes.