Outcomes of stent thrombosis and restenosis during extended follow-up of patients treated with bare-metal coronary stents

The Effect of Angiotensin Receptor Blockers on In-Stent Restenosis After Stent Implantation: A Meta-Analysis

AIM

Angiotensin receptor blockers (ARBs) have been shown to inhibit restenosis in vitro and in vivo, but the evidence found in humans is inconsistent. This study aimed to evaluate the effectiveness of ARBs in preventing in-stent restenosis after percutaneous coronary intervention (PCI).

METHOD

Databases including the Cochrane Library, MEDLINE, Web of Science, EMBASE, and CNKI were searched to collect randomised controlled trials on ARBs inhibiting restenosis that were published before October 2022. A total of 1,056 patients enrolled in eight trials were included in the study.

RESULTS

The ARBs group showed lower target lesion revascularisation than the control group (RR 0.54; 95% CI 0.34-0.86; p=0.01), but the restenosis incidence between these two groups was not statistically significant (RR 0.85; 95% CI 0.65-1.11; p>0.05).

CONCLUSION

This study found that ARBs might have a potential effect on reducing target lesion revascularisation after PCI in coronary heart disease patients but has no impact on angiographic restenosis.

Neoatherosclerosis prediction using plaque markers in intravascular optical coherence tomography images

Introduction

In-stent neoatherosclerosis has emerged as a crucial factor in post-stent complications including late in-stent restenosis and very late stent thrombosis. In this study, we investigated the ability of quantitative plaque characteristics from intravascular optical coherence tomography (IVOCT) images taken just prior to stent implantation to predict neoatherosclerosis after implantation.

Methods

This was a sub-study of the TRiple Assessment of Neointima Stent FOrmation to Reabsorbable polyMer with Optical Coherence Tomography (TRANSFORM-OCT) trial. Images were obtained before and 18 months after stent implantation. Final analysis included images of 180 lesions from 90 patients; each patient had images of two lesions in different coronary arteries. A total of 17 IVOCT plaque features, including lesion length, lumen (e.g., area and diameter); calcium (e.g., angle and thickness); and fibrous cap (FC) features (e.g., thickness, surface area, and burden), were automatically extracted from the baseline IVOCT images before stenting using dedicated software developed by our group (OCTOPUS). The predictive value of baseline IVOCT plaque features for neoatherosclerosis development after stent implantation was assessed using univariate/multivariate logistic regression and receiver operating characteristic (ROC) analyses.

Results

Follow-up IVOCT identified stents with (n = 19) and without (n = 161) neoatherosclerosis. Greater lesion length and maximum calcium angle and features related to FC were associated with a higher prevalence of neoatherosclerosis after stent implantation (p < 0.05). Hierarchical clustering identified six clusters with the best prediction p-values. In univariate logistic regression analysis, maximum calcium angle, minimum calcium thickness, maximum FC angle, maximum FC area, FC surface area, and FC burden were significant predictors of neoatherosclerosis. Lesion length and features related to the lumen were not significantly different between the two groups. In multivariate logistic regression analysis, only larger FC surface area was strongly associated with neoatherosclerosis (odds ratio 1.38, 95% confidence interval [CI] 1.05-1.80, p < 0.05). The area under the ROC curve was 0.901 (95% CI 0.859-0.946, p < 0.05) for FC surface area.

Conclusion

Post-stent neoatherosclerosis can be predicted by quantitative IVOCT imaging of plaque characteristics prior to stent implantation. Our findings highlight the additional clinical benefits of utilizing IVOCT imaging in the catheterization laboratory to inform treatment decision-making and improve outcomes.

Frequency, Risk Factors, and Outcome of Definite Stent Thrombosis: A Single-Center Experience

Introduction

Stent thrombosis (ST) is a serious and potentially life-threatening complication of primary or complex high-risk percutaneous coronary intervention (PCI). Multiple factors are said to precipitate ST, related to the patient's clinical comorbidities, lesion characteristics, operative technique, and post-procedural care. The older-generation stents were thought to be involved in early ST. Though the new generation of drug-eluting stents decreases the incidence of early and late ST, patients are still at risk of very late stent thrombosis (VLST).

Objective

To evaluate the frequency, risk factors, and outcomes of definite ST in developing and resource-constrained countries like Pakistan, where PCIs, including primary PCI, complex PCI, and PCI in high-risk populations, are performed routinely.

Methods

This observational cross-sectional study included all patients who underwent primary and complex high PCI between 2012 and 2017 at TABBA Heart Institute (THI), Karachi, Pakistan.

Results

We included a total of 6587 patients in our study, and among the enrolled sample size, 22 (0.33%) had definite ST. Acute stent thrombosis (AST) was found in seven patients, sub-acute stent thrombosis (SAST) in 10, late stent thrombosis (LST) in two, and VLST were observed in three patients. The basic characteristics of our study ST population were as follows: mean age was 58 years, 95.5% were male, 4.5% were female, nine patients (40%) had diabetes mellitus, 15 patients (68%) had hypertension, 11 (50%) had dyslipidemia, and four patients were smokers (18%).

Conclusion

The frequency, risk factors, and rate of mortality of definite ST in the Pakistani population who underwent primary and complex high-risk PCI reflect nearly equal statistics observed in other studies. As seen in other international studies, the incidence rate of VLST was higher in our population.

Next-Generation Sequencing of CYP2C19 in Stent Thrombosis: Implications for Clopidogrel Pharmacogenomics

PURPOSE

Describe CYP2C19 sequencing results in the largest series of clopidogrel-treated cases with stent thrombosis (ST), the closest clinical phenotype to clopidogrel resistance. Evaluate the impact of CYP2C19 genetic variation detected by next-generation sequencing (NGS) with comprehensive annotation and functional studies.

METHODS

Seventy ST cases on clopidogrel identified from the PLATO trial (n = 58) and Mayo Clinic biorepository (n = 12) were matched 1:1 with controls for age, race, sex, diabetes mellitus, presentation, and stent type. NGS was performed to cover the entire CYP2C19 gene. Assessment of exonic variants involved measuring in vitro protein expression levels. Intronic variants were evaluated for potential splicing motif variations.

RESULTS

Poor metabolizers (n = 4) and rare CYP2C19*8, CYP2C19*15, and CYP2C19*11 alleles were identified only in ST cases. CYP2C19*17 heterozygote carriers were observed more frequently in cases (n = 29) than controls (n = 18). Functional studies of CYP2C19 exonic variants (n = 11) revealed 3 cases and only 1 control carrying a deleterious variant as determined by in vitro protein expression studies. Greater intronic variation unique to ST cases (n = 169) compared with controls (n = 84) was observed with predictions revealing 13 allele candidates that may lead to a potential disruption of splicing and a loss-of-function effect of CYP2C19 in ST cases.

CONCLUSION

NGS detected CYP2C19 poor metabolizers and paradoxically greater number of so-called rapid metabolizers in ST cases. Rare deleterious exonic variation occurs in 4%, and potentially disruptive intronic alleles occur in 16% of ST cases. Additional studies are required to evaluate the role of these variants in platelet aggregation and clopidogrel metabolism.

Robotic-assisted PCI: The future of coronary intervention?

Robotic percutaneous coronary intervention (R-PCI) is a novel approach to performing percutaneous coronary intervention (PCI) whereby the operator can utilise remotely controlled technology to manipulate guidewires and catheter devices. This enables the procedure to be undertaken from within a radiation-shielded cockpit. Success in early trials has led to the release of commercially available robotic platforms which have now received regulatory approval and are available for use in clinical practice. Recent trials evaluating R-PCI have demonstrated high technical success rates with low complication rates. Despite this, a significant number of cases, particularly those with complex anatomy, still require at least partial conversion to a manual procedure. Advantages of R-PCI include accurate stent placement, reduced operator radiation exposure and a presumed reduction in orthopedic injuries. Limitations include current incompatibility with certain intravascular imaging catheters and the inability to manipulate multiple guidewires and stents simultaneously. Patients presenting with ST-elevation myocardial infarction requiring primary-PCI have also largely been excluded from existing R-PCI studies. Given these caveats, R-PCI remains a novel technology and has yet to become commonplace in cardiac catheterisation laboratories, however with increasing safety and feasibility data emerging, it is possible that R-PCI may form part of standard practice in the future.

In-stent restenosis of drug-eluting stents: clinical presentation and outcomes in a real-world scenario

BACKGROUND

Drug-eluting stents (DES) have substantially reduced the incidence of coronary in-stent restenosis (ISR), but the problem persists. Clinical presentation and outcomes of DES-ISR in a real-world scenario remains underreported.

RESULTS

In this retrospective study, we examined medical records of 191 consecutive patients with DES-ISR (210 ISR lesions) hospitalized between January 2013 and December 2017. ISR clinical presentation was classified as acute coronary syndrome (ACS) or non-ACS. Clinical, angiographic features and 1-year outcomes [composite of death, myocardial infarction (MI) and repeat-target lesion revascularization] for these two groups were compared. The mean age of study population was 61 ± 10 years and 81.2% were males. ACS was the dominant clinical presentation mode occurring in 118 (61.8%) patients. MI was seen in 66 (34.6%) patients. Female gender (odds ratio, 2.71; 95% confidence interval [CI], 1.13-6.52; P = 0.026) and chronic kidney disease (odds ratio, 3.85; 95% CI, 1.05-14.20; P = 0.043) correlated significantly with ACS ISR presentation. A majority [104 (54.5%)] of patients underwent percutaneous coronary intervention (PCI), of whom 72 (69.2%) received a new DES. The rest either underwent CABG (26.2%) or received medical therapy (19.4%). Patients presenting with ACS had a significantly worse clinical outcome at 1-year follow-up (ACS versus non-ACS presentation: hazard ratio [HR], 2.66; 95% CI, 1.09-6.50; P = 0.032).

CONCLUSIONS

DES-ISR presents most commonly as ACS. Female gender and chronic kidney disease seem to be associated with ACS presentation. ACS presentation of ISR is associated with worse 1-year outcomes. Early identification of those with ACS risk and closer follow-up may improve outcomes.

Retroperitoneal Hemorrhage After Percutaneous Coronary Intervention: Incidence, Determinants, and Outcomes as Recorded by the British Cardiovascular Intervention Society

BACKGROUND

Retroperitoneal hemorrhage (RH) is a rare bleeding complication of percutaneous coronary intervention, which can result as a consequence of femoral access or can occur spontaneously. This study aims to evaluate temporal changes in RH, its predictors, and clinical outcomes in a national cohort of patients undergoing percutaneous coronary intervention in the United Kingdom.

METHODS AND RESULTS

We analyzed RH events in patients who underwent percutaneous coronary intervention between 2007 and 2014. Multiple logistic regression models were used to identify factors associated with RH and to quantify the association between RH and 30-day mortality and major adverse cardiovascular events. A total of 511 106 participants were included, and 291 in hospital RH events were recorded (0.06%). Overall, rates of RH declined from 0.09% to 0.03% between 2007 and 2014. The strongest independent predictors of RH events were femoral access (odds ratio [OR], 19.66; 95% confidence interval [CI], 11.22-34.43), glycoprotein IIb/IIIa inhibitor (OR, 2.63; 95% CI, 1.99-3.47), and warfarin use (OR, 2.53; 95% CI, 1.07-5.99). RH was associated with a significant increase in 30-day mortality (OR, 3.59; 95% CI, 2.19-5.90) and in-hospital major adverse cardiovascular events (OR, 5.76; 95% CI, 3.71-8.95). A legacy effect was not observed; patients with RH who survived 30 days did not have higher 1-year mortality compared with those without this complication (hazard ratio, 0.97; 95% CI, 0.49-1.91).

CONCLUSIONS

Our results suggest that RH is a rare event that is declining in the United Kingdom, related to transition to transradial access site utilization, but remains a clinically important event associated with increased 30-day mortality but no long-term legacy effect.

Five-year clinical outcomes of everolimus-eluting stents from the post marketing study of CoCr-EES (XIENCE V/PROMUS) in Japan

The Cobalt Chromium Everolimus-Eluting Stent (CoCr-EES) Post Marketing Surveillance (PMS) Japan study is a prospective multicenter registry designed to evaluate the safety and efficacy of XIENCE V/PROMUS everolimus-eluting stents in routine clinical practice at 47 centers representative of the clinical environment in Japan. We enrolled 2010 consecutive patients (2649 lesions) who underwent percutaneous coronary intervention using CoCr-EES. Clinical outcomes were evaluated through 5 years. Mean age was 68.8 years, 41.9% had diabetes, 4.9% received hemodialysis. Five-year clinical follow up was available for 1704 (84.8%) patients. Major adverse cardiovascular events (MACE) occurred in 10.7% of patients, including cardiac death (3.8%), myocardial infarction (1.8%), and clinically driven target lesion revascularization (TLR) (6.0%). Beyond 1 year, annual incidence of clinically driven TLR was 0.5-0.8%. Definite or probable stent thrombosis occurred in 9 (0.5%) patients at 5 years. After 1 year, definite stent thrombosis occurred in only 1 patient. Significant predictors for MACE were dialysis (ODDs ratio 4.58, 95% CI 2.75-7.64), prior cardiac intervention (ODDs ratio 2.47, 95% CI 1.75-3.49), total stent length (ODDs ratio 1.01, 95% CI 1.01-1.02), and number of diseased vessels (ODDs ratio 1.66, 95% CI 1.08-2.55). Five-year clinical outcomes from the CoCr-EES PMS Japan study demonstrated a low incidence of clinical events in the daily practice up to 5 years.Clinical Trial Registration Information: https://clinicaltrials.gov/ct2/show/NCT01086228 .

Optical Frequency Domain Imaging of Very Late Stent Thrombosis Following Bare-Metal Stent Implantation for Acute Myocardial Infarction

A 43-year-old man was admitted to our hospital with ST-segment elevation acute coronary syndrome. He had experienced myocardial infarction 19 months previously, and a bare-metal stent (BMS) had been implanted in the culprit distal right coronary artery at another hospital. Emergency coronary angiography showed thrombotic in-stent occlusion of the BMS. Intravascular ultrasound revealed an undersized stent compared with the size of the vessel and late stent malapposition (LSM) with abundant thrombi. The lesion was successfully recanalized via thrombectomy and plain old balloon angioplasty. Optical frequency domain imaging performed at follow-up coronary angiography confirmed the improvement of the LSM and incomplete neointimal stent coverage. This report illustrates the importance of imaging modalities in elucidating the mechanism of BMS-related very late stent thrombosis.

Molecular signature of coronary stent thrombosis: oxidative stress and innate immunity cells

The clinical impact of in-stent thrombosis is high because it is associated with high mortality and 20 % of the patients suffer a recurrent event within the two following years. The aim of this study was to characterise the morphologic and proteomic profile of in-stent thrombi (IST) in comparison to thrombi developed on native coronary arteries (CT) to identify a differential molecular signature. The study included 45 patients with ST-elevation-myocardial-infarction (STEMI) treated by primary-percutaneous-intervention and thrombus aspiration: 21 had IST and 24 had CT. Thrombi were characterised by morphologic immunohistochemical analysis and differential proteomic profiling (2-DE+MALDI-TOF/TOF). Bioinformatic analysis revealed differences in proteins related to oxidative-stress and cell death/survival. IST showed a higher content of structural proteins (gelsolin, actin-cytoplasmic-1, tropomyosin, and myosin) together with an imbalance in redox-homeostasis related proteins (increased superoxide-dismutase and decreased peroxiredoxin-2 thrombus content), and a coordinated increase of chaperones (HSP60 and HSC70) and cellular quality control-related proteins (26S–protease-regulatory-subunit-7). These changes were reflected into a significant decrease in HSC70 systemic levels and a significant increase in advanced-oxidation-protein-products (AOPP) indicative of increased oxidative stress-mediated protein damage in IST. Our results reveal an imbalance in redox-related proteins indicative of an exacerbated oxidative-stress that leads to an accumulation of AOPP serum levels in IST. Moreover, the coordinated increase in chaperones and regulatory proteins reflects the activation of intracellular protection mechanisms to maintain protein integrity in IST. The failure to counterbalance the stress situation could trigger cellular apoptosis leading to the destabilization of the thrombus and to a worse prognosis of IST-STEMI-patients.

Supplementary Material to this article is available online at www.thrombosis-online.com.

Open-Label Phase I Clinical Study to Assess the Safety and Efficacy of Cilostazol in Patients Undergoing Internal Carotid Artery Stent Placement

BACKGROUND

One-month dual antiplatelet treatment, with aspirin and clopidogrel, following internal carotid artery stent placement is the current standard of care to prevent in-stent thrombosis. Cilostazol, an antiplatelet drug, has been demonstrated to have a safety profile comparable to aspirin and clopidogrel.

OBJECTIVE

To evaluate the safety and clinical efficacy of cilostazol and aspirin therapy following internal carotid artery stent placement up to 1 month postprocedure.

METHODS

A phase I open-label, nonrandomized two-center prospective study was conducted. All subjects received aspirin (325 mg/day) and cilostazol (200 mg/day) 3 days before extracranial stent placement. Two antiplatelet agents were continued for 1 month postprocedure followed by aspirin daily monotherapy. The primary efficacy end point was the 30-day composite occurrence of death, cerebral infarction, transient ischemic attack, and in-stent thrombosis. The primary safety end point was bleeding.

RESULTS

Twelve subjects (mean age ± SD, 66 ± 12 years; 9 males) were enrolled and underwent internal carotid artery angioplasty and stent placement. None of the subjects who successfully followed the study protocol experienced any complications at the 1- and 3-month follow-ups. One patient had a protocol deviation due to concurrent use of enoxaparin (1 mg/kg twice daily) in addition to aspirin and cilostazol, resulting in a fatal symptomatic intracerebral hemorrhage following successful stent placement on postprocedure day 1. One patient discontinued cilostazol after the first dose secondary to dizziness.

CONCLUSION

The use of cilostazol and aspirin for internal carotid artery stent placement appears to be safe, but protocol compliance needs to be emphasized.

Lack of Concordance Between Local Investigators, Angiographic Core Laboratory, and Clinical Event Committee in the Assessment of Stent Thrombosis: Results From the TRACER Angiographic Substudy

BACKGROUND

Stent thrombosis (ST) is an important end point in cardiovascular clinical trials. Adjudication is traditionally based on clinical event committee (CEC) review of case report forms and source documentation rather than angiograms. However, the degree to which this method of adjudication is concordant with the review of independent angiographic core laboratories (ACLs) has not been studied. This report represents the first assessment of variability between local investigators (LIs), a CEC, and an ACL.

METHODS AND RESULTS

Serial angiograms of 329 patients with acute coronary syndrome without ST-segment-elevation who underwent percutaneous coronary intervention at entry in the Trial to Assess the Effects of Vorapaxar in Preventing Heart Attack and Stroke in Particpants With Acute Coronary Syndrome (TRACER) and who met criteria for possible ST subsequent to the index event were reviewed by an ACL. The ACL was blinded to the assessment by both LIs and the CEC regarding the presence or absence of ST. CEC adjudication was based on Academic Research Consortium definitions of ST, using case report form data and source documents, including catheterization laboratory reports. The ACL, CEC, and LIs agreed on the presence or absence of ST in 52.9% events (κ=0.32; 95% confidence interval, 0.26-0.39). The ACL and CEC agreed on 82.7% of events (κ=0.57; 95% confidence interval, 0.47-0.67); the ACL and LIs agreed on 61.1% of events (κ=0.25; 95% confidence interval, 0.16-0.34); and the CEC and LIs agreed on 62% of events (κ=0.28; 95% confidence interval, 0.21-0.36).

CONCLUSIONS

ST reporting by an ACL, a CEC, and LIs is discordant. The assessment of ST is more often detected by direct review of angiograms by an ACL.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00527943.

Perioperative management of patient with intracoronary stent presenting for noncardiac surgery

As the number of percutaneous coronary interventions increase annually, patients with intracoronary stents (ICS) who present for noncardiac surgery (NCS) are also on the rise. ICS is associated with stent thrombosis (STH) and requires mandatory antiplatelet therapy to prevent major adverse cardiac events. The risks of bleeding and ischemia remain significant and the management of these patients, especially in the initial year of ICS is challenging. The American College of Cardiologists guidelines on the management of patients with ICS recommend dual antiplatelet therapy (DAT) for minimal 14 days after balloon angioplasty, 30 days for bare metal stents, and 365 days for drug-eluting stents. Postponement of elective surgery is advocated during this period, but guidelines concerning emergency NCS are ambiguous. The risk of STH and surgical bleeding needs to be assessed carefully and many factors which are implicated in STH, apart from the type of stent and the duration of DAT, need to be considered when decision to discontinue DAT is made. DAT management should be a multidisciplinary exercise and bridging therapy with shorter acting intravenous antiplatelet drugs should be contemplated whenever possible. Well conducted clinical trials are needed to establish guidelines as regards to the appropriate tests for platelet function monitoring in patients undergoing NCS while on DAT.

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.

Contemporary Context of Drug-Eluting Stents in Brazil: A Cost Utility Study

BACKGROUND

Although drug-eluting stents (DES) have been widely incorporated into clinical practice in developed countries, several countries restrict their use mainly because of their high cost and unfavorable incremental cost-effectiveness ratios (ICER).

OBJECTIVE

To evaluate the cost-effectiveness of DES in comparison with bare-metal stents (BMS) for treatment of coronary artery disease (CAD).

DESIGN

Markov model.

DATA SOURCES

Published literature, government database, and CAD patient cohort.

TARGET POPULATION

Single-vessel CAD patients.

TIME HORIZON

One year and lifetime.

PERSPECTIVE

Brazilian Public Health System (SUS).

INTERVENTION

Six strategies composed of percutaneous intervention with a BMS or 1 of 5 DES (paclitaxel, sirolimus, everolimus, zotarolimus, and zotarolimus resolute).

OUTCOME MEASURES

Cost for target vessel revascularization avoided and cost for quality-adjusted life year gained.

BASE CASE ANALYSIS

In the short-term analysis, sirolimus was the most effective and least costly among DES (ICER of I$20,642 per target vessel revascularization avoided), with all others DES dominated by sirolimus. Lifetime cumulative costs ranged from I$18,765 to I$21,400. In the base case analysis, zotarolimus resolute had the most favorable ICER among the DES (ICER I$62,761), with sirolimus, paclitaxel, and zotarolimus being absolute dominated and everolimus extended dominated by zotarolimus resolute, although all the results were above the willingness-to-pay threshold of 3 times the gross domestic product per capita (I$35,307).

SENSITIVITY ANALYSIS

In deterministic sensitivity analysis, results were sensitive to cost of DES, number of stents used per patient, baseline probability, and duration of stent thrombosis risk. The probabilistic sensitivity analysis demonstrated a probability of 81% for BMS being the strategy of choice, with 9% for everolimus and 9% zotarolimus resolute, at the willingness-to-pay threshold.

CONCLUSION

DES is not a good value for money in SUS perspective, despite its benefit in reducing target vessel revascularization. Since the cost-effectiveness of DES is mainly driven by the stents' cost difference, they should cost less than twice the BMS price to become a cost-effective alternative.

The Tradeoff Between Shorter and Longer Courses of Dual Antiplatelet Therapy After Implantation of Newer Generation Drug-Eluting Stents

The benefit of prolonged dual antiplatelet therapy (DAPT) after implantation of drug-eluting stents (DESs) remains uncertain. In 10 randomized controlled trials (RCTs) of 31,666 predominantly low-risk patients undergoing DES implantation, shorter courses (3-12 months) of DAPT resulted in lower mortality (odds ratio [OR] 0.83, 95 % confidence interval [CI] 0.69-0.98) and major hemorrhage (OR 0.60, 95 % CI 0.48-0.75) but increased myocardial infarction (MI, OR 1.34, 95 % CI 1.04-1.73) and stent thrombosis (ST, OR 1.75, 95 % CI 1.08-2.82) than did longer courses (12-36 months) of DAPT. A risk-benefit analysis identified 3 fewer deaths and 5 fewer bleeds but 4 more MIs and 3 more STs annually for every 1000 patients treated with the shorter courses. In the predominantly low-risk population enrolled in RCTs, limiting DAPT to 3 to 12 months after DES implantation saved lives and prevented bleeding at the expense of increased ST and MI.

Influence of Sex on Long-Term Outcomes After Implantation of Bare-Metal Stent

Background—

Female sex was reported to be associated with lower risk for midterm restenosis and repeat revascularization after bare-metal stent implantation. However, the influence of sex on very long-term outcomes after bare-metal stent implantation has not been yet reported.

Methods and Results—

Among the 9877 patients in the multicenter Coronary Revascularization Demonstrating Outcome study in Kyoto (CREDO-Kyoto) registry cohort-1, bare-metal stent implantation was performed in 5313 patients (men, n=3742 and women, n=1571). Follow-up was completed in 4515 patients (85.0%) at 10 years (duration, 10.3±3.1 [0.0–14.1] years). The cumulative incidence of target-lesion revascularization (TLR) was 27% at 1 year and 34% at 10 years (0.8%/y beyond 1 year). Non–target-lesion revascularization (non-TLR) was the dominant coronary revascularization beyond 1 year (13% at 1 year and 31% at 10 years [2.0%/y beyond 1 year]). Cumulative incidence of stent thrombosis was low (1.2% at 1 year and 1.9% at 10 years). Women were older and had greater prevalence of cardiovascular risk factors than men. The cumulative 10-year incidences of and adjusted risk for TLR were significantly higher in men than in women (36% versus 30%, P <0.001; adjusted hazard ratio, 1.29; 95% confidence interval, 1.15–1.46; P <0.001). The higher risk of men relative to women for TLR was consistent regardless of age (<75 years and ≥75 years). Men in comparison with women were also associated with significantly higher adjusted risks for all-cause death, myocardial infarction, stroke, coronary artery bypass grafting, TLR, and non-TLR.

Conclusions—

TLR and stent thrombosis continued to occur without attenuation up to 10 years after bare-metal stent implantation. Men in comparison with women were associated with higher adjusted 10-year risks for all-cause death, myocardial infarction, stroke, coronary artery bypass grafting, TLR, and non-TLR.

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.

Investigation of the dynamic diameter deformation of vascular stents during fatigue testing with radial loading

Endovascular stents are exposed to cyclic loads resulting from daily activity and pulsatile arterial blood pressure. DIN EN ISO 25539-2 and FDA guideline 1545 recommend durability testing, exposing stents to physiological cyclic loads for a 10 year equivalent. For accelerated testing, the simulated deformation has to be comparable to physiological in-vivo deformation. A new test setup is presented to determine diameter deformation of vascular stents during fatigue testing with radial loading.

Methods

The new setup allows the investigation of stents (n = 1–10) up to a length of 200 mm using a CCD line camera independent from special configurations. For demonstration, the radial deformation of two peripheral stents (stent 1: 8.0×40 mm, stent 2: 4.5×40 mm) and coronary stents (stent 3: 2.5×22 mm, stent 4: 4.0×40 mm) is determined as a function of the longitudinal measuring position. The stents are implanted in polyurethane tubes and exposed to physiologically relevant pressure at test frequencies 100 Hz.

Results

In addition to the verification of test frequencies for fatigue testing the setup can also be used for the investigation of radial deformation performance. The results show that radial deformation may vary along the stent length. Larger radial deformation was detected at the middle of the stent. For stent 1 a maximum deformation of 0.21 ± 0.07 mm (± 2.65 %) was measured at 50 ± 40 mmHg, 90 Hz. It was also measured that the radial deformation is dependent on stent design, geometric dimension and external loading.

Conclusion

The new setup allows for test frequency verification for accelerated fatigue testing with radial loading. It is also suitable for more detailed investigation of the radial deformation performance of stents along their longitudinal axis. This is necessary for a better understanding of potential mechanical failure especially in the case of long or overlapping stents.

Bare-metal stent thrombosis two decades after stenting

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

Does aspirin administration increase perioperative morbidity in patients with cardiac stents undergoing spinal surgery?

STUDY DESIGN

Cohort.

OBJECTIVE

To compare the perioperative morbidity of patients with cardiac stents after spine surgery who continue to take aspirin before and after the operation with a similar group of patients who preoperatively discontinued aspirin.

SUMMARY OF BACKGROUND DATA

The preoperative discontinuation of anticoagulant therapy has been the standard of care for orthopedic surgical procedures. However, recent literature has demonstrated significant cardiac risk associated with aspirin withdrawal in patients with cardiac stents. Although it has recently been demonstrated that performing orthopedic surgery while continuing low-dose aspirin therapy seems to be safe, studies focused on spinal surgery have not yet been performed. Because of the risk of intraspinal bleeding and the serious consequences of subsequent epidural hematoma with associated spinal cord compression, spinal surgeons have been reluctant to operate on patients taking aspirin.

METHODS

This institutional review board-approved study included 200 patients. Preoperative parameters and postoperative outcome measures were analyzed for 100 patients who underwent spinal surgery after the discontinuation of anticoagulation therapy and 100 patients who continued to take daily aspirin through the perioperative period. The primary outcome measure was serious bleeding-related postoperative complications such as spinal epidural hematoma. The operative time, intraoperative estimated blood loss, hospital length of stay, transfusion of blood products, and 30-day hospital readmission rates were also recorded and compared.

RESULTS

The patients who continued taking aspirin in the perioperative period had a shorter hospital length of stay on average (4.1 ± 2.7 vs. 6.2 ± 5.8; P < 0.005), as well as a reduced operative time (210 ± 136 vs. 266 ± 143; P < 0.01), whereas there was no significant difference in the estimated blood loss (642 ± 905 vs. 697 ± 1187), the amount of blood products transfused, overall intra- and postoperative complication rate (8% vs. 11%), or 30-day hospital readmission rate (5% vs. 5%). No clinically significant spinal epidural hematomas were observed in either of the study groups.

CONCLUSION

The current study has observed no appreciable increase in bleeding-related complication rates in patients with cardiac stents undergoing spine surgery while continuing to take aspirin compared with patients who discontinued aspirin prior to surgery. Although very large studies will be needed to determine whether aspirin administration results in a small complication rate increase, the current study provides evidence that perioperative aspirin therapy is relatively safe in patients undergoing spinal surgery.

LEVEL OF EVIDENCE

2.

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.

Clinical Presentation and Outcomes of Coronary In-Stent Restenosis Across 3-Stent Generations

Background—

Clinical presentation of bare metal stent in-stent restenosis (ISR) in patients undergoing target lesion revascularization is well characterized and negatively affects on outcomes, whereas the presentation and outcomes of first- and second-generation drug-eluting stents (DESs) remains under-reported.

Methods and Results—

The study included 909 patients (1077 ISR lesions) distributed as follows: bare metal stent (n=388), first-generation DES (n=425), and second-generation DES (n=96), categorized into acute coronary syndrome (ACS) or non-ACS presentation mode at the time of first target lesion revascularization. ACS was further classified as myocardial infarction (MI) and unstable angina. For bare metal stent, first-generation DES and second-generation DES, ACS was the clinical presentation in 67.8%, 71.0%, and 66.7% of patients, respectively ( P =0.470), whereas MI occurred in 10.6%, 10.1%, and 5.2% of patients, respectively ( P =0.273). The correlates for MI as ISR presentation were current smokers (odds ratio, 3.02; 95% confidence interval [CI], 1.78–5.13; P <0.001), and chronic renal failure (odds ratio, 2.73; 95% CI, 1.60–4.70; P <0.001), with a protective trend for the second-generation DES ISR (odds ratio, 0.35; 95% CI, 0.12–1.03; P =0.060). ACS presentations had an independent effect on major adverse cardiac events (death, MI, and re-target lesion revascularization) at 6 months (MI versus non-ACS: adjusted hazard ratio, 4.06; 95% CI, 1.84–8.94; P <0.001; unstable angina versus non-ACS: adjusted hazard ratio, 1.98; 95% CI, 1.01–3.87; P =0.046).

Conclusions—

ISR clinical presentation is similar irrespective of stent type. MI as ISR presentation seems to be associated with patient and not device-related factors. ACS as ISR presentation has an independent effect on major adverse cardiac events, suggesting that ISR remains a hazard and should be minimized.

Association of localized hypersensitivity and in-stent neoatherosclerosis with the very late drug-eluting stent thrombosis

BACKGROUND

Localized hypersensitivity reaction, delayed arterial healing, and neoatherosclerosis inside the stent have been suggested as the underlying pathologic mechanisms of very late stent thrombosis (VLST) of drug-eluting stent (DES). The present study sought to explore the prevalence of inflammatory cell infiltrates and evidence for fragments of atherosclerotic plaques in the aspirated thrombi in patients with DES VLST.

METHODS AND RESULTS

From April 2004 to September 2012, 48 patients with stent thrombosis (ST) of DES underwent thrombus aspiration with retrieved material sufficient for the histopathologic analysis; early ST (EST, within 30 days): N = 17, late ST (LST, between 31 and 365 days): N = 7, and very late ST (VLST, >1 year): N = 24. Eosinophil fraction in the aspirated thrombi was significantly higher in patients with VLST (8.2±5.7%) as compared with those with EST (4.3±3.0%) and LST (5.5±3.8%) (P = 0.03). Eosinophil fraction in the aspirated thrombi was significantly higher in 12 VLST patients with angiographic peri-stent contrast staining (PSS) and/or incomplete stent apposition (ISA) by intravascular ultrasound than in 12 VLST patients without PSS or ISA (10.6±6.1% versus 5.8±4.1%, P = 0.03). Evidences for fragments of atherosclerotic plaques in the aspirated thrombi were observed only in 3 (13%) out of 24 patients with DES VLST.

CONCLUSIONS

Eosinophil fraction in the aspirated thrombi was significantly higher in patients with DES VLST as compared with those with EST and LST. Evidences for fragments of atherosclerotic plaques were relatively uncommon in patients with DES VLST.

Novel bioresorbable stent coating for drug release in congenital heart disease applications

A novel double opposed helical poly-l-lactic acid (PLLA) bioresorbable stent has been designed for use in pediatrics. The aim was to test the PLLA stent biocompatibility. The PLLA stent was immersed into whole pig's blood in a closed loop circuit then fibrin and platelet association was assessed via enzyme-linked immunosorbent assay. D-Dimer was valued at 0.2 ± 0.002 ng/mL and P-selectin 0.43 ± 00.01 ng/mL indicating limited association of fibrin and platelets on the stent. To improve biocompatibility by targeting inflammatory cells, dexamethasone was incorporated on PLLA fibers with two coating methods. Both coatings were poly(l-lactide-co-glycolide) acid (PLGA) but one was made porous with sucrose while the other remained nonporous. There was no change in mechanical properties of the fiber with either coating of PLGA polymer. The total amount of dexamethasone released was then determined for each coating. The cumulative drug release for the porous fiber was significantly higher (∼100%) over 8 weeks than the nonporous fiber (40%). Surface examination of the fiber with scanning electron microscopy showed more surface microfracturing in coatings that contain pores. The biocompatibility of this novel stent was demonstrated. Mechanical properties of the fiber were not altered by coating with PLGA polymer. Anti-inflammatory drug release was optimized using a porous PLGA polymer.

Evolving management of patients treated by drug-eluting stent: prevention of late events

SUMMARY

Drug eluting stents (DES) were introduced in clinical practice to overcome the problem of in-stent restenosis (ISR) that limited the overall efficacy of percutaneous coronary revascularization with bare metal stent (BMS). Long-term outcome data confirm a sustained benefit of DES as compared with BMS. However, this benefit is mainly evident in the first year of follow-up. Indeed, DES-related events may extend over this time, due to late events (late ISR and/or very late stent thrombosis). Prevention of late failure of DES may become a specific therapeutic target.

Impact of angiographic peri-stent contrast staining (PSS) on late adverse events after sirolimus-eluting stent implantation: an observation from the multicenter j-Cypher registry PSS substudy

This study sought to assess clinical significance of angiographic peri-stent contrast staining (PSS) after sirolimus-eluting stent (SES) implantation in a large multicenter study with 5-year follow-up. The j-Cypher PSS substudy is a multicenter study including 5712 patients (7838 lesions) who underwent follow-up angiographic study within 12 months after SES implantation. Late acquired PSS was observed in 184 patients (3.2 %) or 194 lesions (2.5 %). Independent risk factors of PSS were chronic total occlusion and left anterior descending artery lesion, while negative risk factors were in-stent restenosis, diabetes mellitus, ≥70 years of age, and left circumflex coronary artery lesion. Cumulative incidence of definite very late stent thrombosis (VLST) at 4 years after the index follow-up angiography in lesions with PSS was significantly higher than that in lesions without PSS (5.3 versus 0.7 %, P < 0.0001). Late target-lesion revascularization (TLR) was also more frequently observed in the PSS group (13 versus 6.9 %, P = 0.01), while late TLR for restenosis excluding those TLR procedures for VLST tended to be higher in the PSS group (9.9 versus 6.3 %; P = 0.15). PSS found in 2.5 % of lesions within 12 months after SES implantation was associated with higher risk for subsequent VLST.

Intra-stent tissue evaluation within bare metal and drug-eluting stents > 3 years since implantation in patients with mild to moderate neointimal proliferation using optical coherence tomography and virtual histology intravascular ultrasound

OBJECTIVE

We aimed to compare neointimal tissue characteristics between bare-metal stents (BMS) and drug-eluting stents (DES) at long-term follow-up using optical coherence tomography (OCT) and virtual histology intravascular ultrasound (VH-IVUS).

BACKGROUND

Neoatherosclerosis in neointima has been reported in BMS and in DES.

METHODS

Thirty patients with 36 stented lesions [BMS (n=17) or DES (n=19)] >3years after implantation were prospectively enrolled. OCT and VH-IVUS were performed and analyzed independently. Stents with ≥70% diameter stenosis were excluded.

RESULTS

The median duration from implantation was 126.0months in the BMS group and 60.0months in the DES group (p <0.001). Lipid-laden intima (58.8% vs. 42.1%, p=0.317), thrombus (17.6% vs. 5.3%, p=0.326), and calcification (35.3% vs. 26.3%, p=0.559) did not show significant differences between BMS and DES. When divided into 3 time periods, the cumulative incidence of lipid-laden neointima from >3years to <9years was similar between BMS and DES (42.9% vs. 42.1%, p=1.000). Furthermore, it continued to gradually increase over time in both groups. OCT-derived thin-cap fibroatheroma (TCFA) was observed in 17.6% of BMS- and 5.3% of DES-treated lesions (p=0.326). No stents had evidence of intimal disruption. The percentage volume of necrotic core (16.1% [9.7, 20.3] vs. 9.7% [7.0, 16.5], p=0.062) and dense calcium (9.5% [3.8, 13.6] vs. 2.7% [0.4, 4.9], p=0.080) in neointima tended to be greater in BMS-treated lesions. Intra-stent VH-TCFA (BMS vs. DES 45.5% vs. 18.2%, p=0.361) did not differ significantly.

CONCLUSION

At long-term follow-up beyond 3 years after implantation, the intra-stent neointimal tissue characteristics appeared similar for both BMS and DES.

Causes of very late stent thrombosis investigated using optical coherence tomography

OBJECTIVE

Very late stent thrombosis (VLST) remains an unresolved problem, and recent reports have indicated that VLST onset can occur in patients treated with both drug-eluting stents (DES) and bare metal stents (BMS). We evaluated the causes of VLST using optical coherence tomography (OCT).

METHODS

OCT was performed in 22 patients (12 DES-treated patients, 10 BMS-treated patients). Because two instances of VLST occurred simultaneously in one case in the DES group, the DES group comprised 13 lesions, while the BMS group comprised 10 lesions. All struts were counted in each frame, and the proportion of uncovered or malapposed struts was calculated based on the overall number of struts in the stent.

RESULTS

The interval from stent implantation to VLST onset was significantly longer in the BMS group. The proportion of uncovered struts and the ratio of malapposed struts were significantly higher in the DES group than in the BMS group. The OCT analysis demonstrated intimal hyperplasia or intimal disruption in all patients in the BMS group. However, in the DES group, severe hyperplasia and/or neoatherosclerosis was observed in only eight lesions (61.5%), while uncovered and malapposed struts were involved in the other lesions.

CONCLUSION

In most BMS-treated lesions, it appeared that VLST was caused by the occurrence of neoatherosclerosis after stent implantation. The causes of VLST in DES-treated lesions are more various and complicated than those observed for BMS-treated lesions.

Stent malapposition, as a potential mechanism of very late stent thrombosis after bare-metal stent implantation: a case report

A 90-year-old man was admitted to our hospital with acute ST-segment elevation myocardial infarction. He had a history of post-infarction angina pectoris 79months ago and had a bare-metal stent (BMS) implanted in the proximal left anterior descending artery at our hospital. Emergent coronary angiography demonstrated thrombotic occlusion in the previously stented segment. After catheter thrombectomy, antegrade flow was restored, but 90% stenosis with haziness persisted in the proximal and distal portions of the previously stented segment. Intravascular ultrasound imaging showed interstrut cavities or stent malapposition at the proximal and distal sites of stented segment. In close proximity to the sites, residual thrombi were also observed. Optical coherence tomography (OCT) demonstrated neither lipid-laden neointimal tissue nor rupture but clearly demonstrated residual thrombus adjacent to the malapposed region in addition to the stent malapposition. PCI with balloon was successfully performed and stent apposition was confirmed by OCT. Stent malapposition is an unusual mechanism of very late stent thrombosis after BMS implantation. OCT can clearly reveal the etiology of stent thrombosis.

Long-term outcomes of drug-eluting stent therapy for in-stent restenosis versus de novo lesions

BACKGROUND

Drug-eluting stents (DES) are currently the most popular treatment modality for restenosis in bare metal stents and DES. This study compares risks of adverse cardiovascular events between DES-treated in-stent restenosis (ISR) and de novo lesions, an area that has not been systematically studied thus far.

METHODS AND RESULTS

One thousand three hundred consecutive ISR patients were compared with 27,211 patients with de novo lesions who underwent DES treatment during the same period at the Fu Wai Hospital in Beijing. Angiographic success rate was similar between the ISR and de novo groups (98.0% vs. 98.2%; P = 0.61). Using logistic regression to derive the propensity score model, 1,266 matched patient pairs were compared. In this adjusted model, the rate of target lesion revascularization (TLR) was significantly higher in the ISR group (19.19% vs. 2.37%; P < 0.01) during an average 17-month follow-up, while rates of cardiac death and myocardial infarction (MI) were similar (0.71% vs. 0.79%; P = 0.93 and 3.48% vs. 1.26%; P = 0.13, respectively) between groups. In multivariate regression analysis, ISR was predictive of TLR, but not of cardiac death and MI.

CONCLUSION

Compared with those with de novo lesions, patients with ISR had a higher revascularization rate after DES treatment but no significant difference in rates of cardiac death and MI.