Stent thrombosis and major clinical events at 3 years after zotarolimus-eluting or sirolimus-eluting coronary stent implantation: a randomised, multicentre, open-label, controlled trial

Smoking and Activated Clotting Time during coronary angiography and angioplasty: protocol for the ACT-Tobacco trial

Background

During percutaneous transluminal coronary angioplasty (PTCA), activated clotting time (ACT) measurements are recommended to attest a correct anticoagulation level and, if needed, to administer further unfractionated heparin (UFH) to obtain a therapeutic ACT value. Our clinical routine led us to observe that smokers had lower ACT values after standardized UFH administration during PTCA. Procoagulant status in smokers is well documented.

Objectives

To determine whether tobacco negatively affects UFH anticoagulation during PTCA when evaluated by ACT.

Methods

The ACT-TOBACCO trial is a single-center, noninterventional, prospective study. The primary end point is the comparison of ACT values after standardized UFH administration between active smokers and nonsmokers (active smoker group vs nonsmoker group) requiring coronary angiography followed by PTCA. The main secondary end points include ACT comparison after the first and second standardized UFH administration according to the patient's smoking status (active, ex-, or nonsmoker) and the clinical presentation of ischemic cardiomyopathy: stable (silent ischemia or stable angina) or unstable (unstable angina or acute coronary syndrome without or with ST-segment elevation).

Conclusions

To the best of our knowledge, ACT values during PTCA between smokers and nonsmokers have not previously been compared. As current PTCA procedures increase in complexity and duration, the understanding of procoagulant risk factors such as smoking and the need for reliable anticoagulation monitoring becomes essential to balance hemorrhagic risk against thrombotic risk.

Temporal trends in clinical outcomes after percutaneous coronary intervention: a systematic review of 66,327 patients from 25 all-comers trials

BACKGROUND

With the improvements of percutaneous coronary intervention (PCI) technology and post-PCI patient management, several registry studies reported temporal trends in post-PCI clinical outcomes. However, their results are inconclusive, potentially reflecting region-specific trends, based on site-reported events without external validity.

AIMS

This study aimed to investigate temporal trends in post-PCI clinical outcomes in all-comers randomised controlled trials (RCTs) involving coronary stents.

METHODS

We performed a systematic review identifying RCTs comparing a clinical outcome as a primary endpoint among different coronary stents with an all-comers design and independent clinical event adjudication, extracting the study start year, patient baseline characteristics, and one- and five-year clinical outcomes. Temporal trends in clinical outcomes (cardiac death, myocardial infarction [MI], target lesion revascularisation [TLR], stent thrombosis [ST]) were assessed using random-effects meta-regression analyses, estimating the relationship between clinical outcomes and study start year.

RESULTS

Overall, 25 all-comers trials (51 device arms, 66,327 patients) conducted between 2003 and 2018 fulfilled the eligibility criteria. Random-effects meta-regression analysis revealed significant decreasing trends in one- and five-year cardiac death, one-year TLR, and five-year ST incidences (relative risk per 10-year increase: 0.69 [0.51-0.92], 0.66 [0.44-0.98], 0.60 [0.41-0.88], and 0.18 [0.07-0.44], respectively). There was no significant trend in myocardial infarction incidences.

CONCLUSIONS

This is the first attempt to clarify and quantify the temporal trends of post-PCI outcome incidence. The 15-year improvements in PCI therapy and post-therapeutic patient management are associated with reduced incidences of cardiac death and PCI-related adverse events.

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

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

Stent-Related Adverse Events as Related to Dual Antiplatelet Therapy in First- vs Second-Generation Drug-Eluting Stents

Background

There are limited data on the long-term stent-related adverse events as related to the duration of dual antiplatelet therapy (DAPT) in second-generation (G2) drug-eluting stents (DES) compared with first-generation (G1) DES.

Objectives

This study sought to compare the long-term stent-related outcomes of G2-DES with those of G1-DES.

Methods

The study group consisted of 15,009 patients who underwent their first coronary revascularization with DES from the CREDO-Kyoto PCI/CABG (Coronary Revascularization Demonstrating Outcome Study in Kyoto Percutaneous Coronary Intervention/Coronary Artery Bypass Grafting) Registry Cohort-2 (first-generation drug-eluting stent [G1-DES] period; n = 5,382) and Cohort-3 (second-generation drug eluting stent [G2-DES] period; n = 9,627). The primary outcome measures were definite stent thrombosis (ST) and target vessel revascularization (TVR).

Results

The cumulative 5-year incidences of definite ST and TVR were significantly lower in the G2-DES group than in the G1-DES group (0.7% vs 1.4%; P < 0.001; and 16.2% vs 22.1%; P < 0.001, respectively). The lower adjusted risk of G2-DES relative to G1-DES for definite ST and TVR remained significant (HR: 0.53; 95% CI: 0.37-0.76; P < 0.001; and HR: 0.74; 95% CI: 0.68-0.81; P < 0.001, respectively). In the landmark analysis that was based on the DAPT status at 1 year, the lower adjusted risk of on-DAPT status relative to off-DAPT was significant for definite ST beyond 1 year in the G1-DES stratum (HR: 0.42; 95% CI: 0.24-0.76; P = 0.004) but not in the G2-DES stratum (HR: 0.66; 95% CI: 0.26-1.68; P = 0.38) (P_interaction = 0.14).

Conclusions

G2-DES compared with G1-DES were associated with a significantly lower risk for stent-related adverse events, including definite ST and TVR. DAPT beyond 1 year was associated with a significantly lower risk for very late ST of G1-DES but not for that of G2-DES.

Application of Modern Clinical Risk Scores in the Global Assessment of Risks Related to the Diagnosis and Treatment of Acute Coronary Syndromes in Everyday Medical Practice

This article presents an overview of contemporary risk assessment systems used in patients with myocardial infarction. The full range of risk scales, both recommended by the European Society of Cardiology and others published in recent years, is presented. Scales for assessing the risk of ischemia/death as well as for assessing the risk of bleeding are presented. A separate section is devoted to systems assessing the integrated risk associated with both ischemia and bleeding. In the first part of the work, each of the risk scales is described in detail, including the clinical trials/registers on the basis of which they were created, the statistical methods used to develop them, as well as the specification of their individual parameters. The next chapter presents the practical application of a given scale in the patient risk assessment process, the timing of its application on the timeline of myocardial infarction, as well as a critical assessment of its potential advantages and limitations. The last part of the work is devoted to the presentation of potential directions for the development of risk assessment systems in the future.

Safety considerations with the use of platelet inhibitors for elderly patients with non-ST- elevation acute coronary syndrome

Introduction: Dual antiplatelet therapy (DAPT) is standard treatment for patients with acute coronary syndrome (ACS). This includes lifelong aspirin combined with a P2Y₁₂ inhibitor for 1 year. The indication for one of the P2Y₁₂ inhibitors (clopidogrel, prasugrel, ticagrelor) is dependent on the treatment strategy; whether patients undergo coronary angiography or are treated medically only. Tailoring antiplatelet therapy to the risk profile of the individual patient is of specific importance to the older patient.Areas covered: In this review, we discuss dual antiplatelet therapy in elderly patients with ACS. We present the options to tailor antiplatelet therapy based on platelet function testing, CYP2C19 genotyping and patients' thrombotic and bleeding risk. Finally, we discuss alternatives for dual antiplatelet therapy.Expert opinion: DAPT in elderly patients with ACS should consist of aspirin with clopidogrel or ticagrelor. Weighing patients' thrombotic and bleeding risk, based on clinical judgment or with use of specific risk scores, is probably the most convenient method to individualize antiplatelet therapy; however, CYP2C19 genotyping can also be used. In elderly patients with an increased bleeding risk, clopidogrel is a safe and effective alternative to ticagrelor. An alternative to 12 months DAPT could be ticagrelor monotherapy after a short period of DAPT.

The Use of Bioactive Polymers for Intervention and Tissue Engineering: The New Frontier for Cardiovascular Therapy

Coronary heart disease remains one of the leading causes of death in most countries. Healthcare improvements have seen a shift in the presentation of disease with a reducing number of ST-segment elevation myocardial infarctions (STEMIs), largely due to earlier reperfusion strategies such as percutaneous coronary intervention (PCI). Stents have revolutionized the care of these patients, but the long-term effects of these devices have been brought to the fore. The conceptual and technologic evolution of these devices from bare-metal stents led to the creation and wide application of drug-eluting stents; further research introduced the idea of polymer-based resorbable stents. We look at the evolution of stents and the multiple advantages and disadvantages offered by each of the different polymers used to make stents in order to identify what the stent of the future may consist of whilst highlighting properties that are beneficial to the patient alongside the role of the surgeon, the cardiologist, engineers, chemists, and biophysicists in creating the ideal stent.

Utility of the dual antiplatelet therapy score to guide antiplatelet therapy: A systematic review and meta-analysis

BACKGROUND

The dual antiplatelet therapy (DAPT) score, one of the first prediction tools to attempt to uncouple bleeding and ischemic risk following percutaneous coronary intervention, can help guide antiplatelet duration after coronary intervention. Evaluating the generalizability of the score is important to understand its utility in clinical practice.

METHODS

We conducted a systematic review and meta-analysis of studies that validated the DAPT score. A random effect meta-analysis was performed of ischemic and bleeding risk based on DAPT score. A secondary analysis assessed the risk of longer versus shorter P2Y₁₂ inhibitor duration on ischemic and bleeding risk in randomized controlled trials of DAPT duration.

RESULTS

We identified 10 patient cohorts involving 88,563 patients. Compared with a low DAPT score, a high DAPT score was associated with increased ischemic risk (RR: 1.62, 95% CI: 1.41-1.87) and reduced bleeding risk (RR: 0.80, 95% CI: 0.70-0.92). In three randomized trials of DAPT duration that contained information on the DAPT score, the relative risk of net adverse clinical events (combined ischemic and bleeding events) with longer duration of DAPT was 1.56 (95% CI: 0.77-3.19) for low DAPT score patients, and 0.86 (95% CI: 0.61-1.21) for high DAPT score patients (p_interaction = .14).

CONCLUSIONS

In this large meta-analysis, the DAPT score consistently stratified bleeding and ischemic risk in opposing directions across several different study populations. More evaluation is needed to understand if the effect of longer DAPT duration on NACE is modified by the DAPT score in current practice.

Impact of Periprocedural Myocardial Biomarker Elevation on Mortality Following Elective Percutaneous Coronary Intervention

OBJECTIVES

This study sought to explore the association between biomarker elevation, with creatine kinase-myocardial band (CK-MB) or cardiac troponin (cTn), following percutaneous coronary intervention (PCI) and mortality in patients undergoing PCI for stable angina with normal baseline values.

BACKGROUND

Several studies have shown a strong association between post-PCI CK-MB elevation and subsequent mortality. However, the prognostic significance of troponin elevation following coronary intervention is still debated.

METHODS

Patient-level data from 5 contemporary coronary stent trials and 1 large registry were pooled. Mortality of patients with stable angina, with normal baseline biomarkers, was compared between patients with and those without different cutoff values of cTn and CK-MB.

RESULTS

A total of 13,452 patients were included in this pooled analysis. The overall percentage of patients with elevated biomarkers following PCI was 23.9% for CK-MB and 68.4% for cTn. In the patient cohort for whom both assays were available (n = 8,859), 2.4% had both CK-MB ≥5 × the upper limit of normal (ULN) and cTn ≥35 × ULN, while 92% had both CK-MB <5 × ULN and cTn <35 × ULN. Among patients with CK-MB ≥5 × ULN (n = 315), 212 (67.3%) also had cTn ≥35 × ULN. Conversely, 390 of patients (64.8%) who had cTn ≥35 × ULN did not have CK-MB ≥5 × ULN. A total of 259 patients (1.9%) died at 1 year; 20 (7.7%) had CK-MB ≥5 × ULN, and 23 (8.8%) had cTn ≥35 × ULN. In the Cox multivariate analysis, in which the CK-MB and cTn ratios post-procedure were forced into the model, age, prior myocardial infarction, lesion complexity, hyperlipidemia, and CK-MB ratio (≥10) post-procedure were associated with increased 1-year mortality.

CONCLUSIONS

Following elective PCI in patients in stable condition treated with second-generation drug-eluting stent, CK-MB and cTn elevations remain common. After multivariate adjustment, there was an increased mortality rate with elevation of CK-MB after PCI, whereas cTn elevation was not independently associated with mortality at 1 year.

High nitrogen stainless steel drug-eluting stent - Assessment of pharmacokinetics and preclinical safety in vivo

Pharmacokinetic analyses were performed using 20 pigs for 120-days implantation, while one sirolimus-eluting stent was implanted into one of their coronary artery. At different time points, the residual sirolimus on the stent, delivered locally (to artery wall), regionally (to adjacent and downstream muscle) and systemically (to plasma and visceral organs), was detected throughout 120 days. Preclinical safety evaluation was performed using 32 pigs for 180-days implantation to study the safety of metal platform material and the effectiveness of sirolimus eluting coating on the HNS stent. The neointima area, restenosis rate and inflammatory grade for HNS and control group stents were detected and analyzed. Approximately 80% sirolimus was eluted from the sirolimus-eluting stents after 30-days implantation in vivo. Additionally, there was sustained sirolimus in the artery wall, cardiac muscle and heart throughout 120-days implantation, and sirolimus accumulated to the peak at 90-days implantation. It was inferred that the sirolimus eluting stent in this study was covered by neointima before 90-days implantation, indicating that the sirolimus eluting coating on the HNS stent was safe and effective. Very little sirolimus was distributed in visceral organs after 14-days implantation. HNS sirolimus-eluting stent exhibited lower restenosis rate and lower inflammatory grade than control group, which verified that the sirolimus-eluting coating design in this study was reasonable and practical. In addition, there were no significant difference in restenosis rate and inflammatory score between HNS bare-metal stent and drug-eluting stents, illustrating that HNS has good bio-compatibility and is suitable to use as coronary artery stent material.

•

First time to investigate the pharmacokinetics of drug eluting stents for 120 days, found the relationship between the pharmacokinetics and tissue response, which has been rarely reported.

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Verified that the drug-eluting stent made of high nitrogen stainless steel endothelialization finished after 90 days implantation, without endothelialization delay.

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HNS has been proved that it is a better biocompatibility and bio-safe metal platform material, owing better property to be used in clinic.

Three-year clinical outcome of biodegradable hybrid polymer Orsiro sirolimus-eluting stent and the durable biocompatible polymer Resolute Integrity zotarolimus-eluting stent: A randomized controlled trial

AIMS

We compared long-term clinical outcomes between patients treated with Orsiro sirolimus-eluting stent (O-SES) and those treated with durable biocompatible polymer Resolute Integrity zotarolimus-eluting stent (R-ZES).

METHODS AND RESULTS

The ORIENT trial was a randomized controlled noninferiority trial to compare angiographic outcomes between O-SES and R-ZES. We performed a post hoc analysis of 3-year clinical outcomes and included 372 patients who were prospectively enrolled and randomly assigned to O-SES (n = 250) and R-ZES (n = 122) groups in a 2:1 ratio. The primary endpoint was target lesion failure defined as a composite of cardiac death, nonfatal myocardial infarction, and target lesion revascularization. At 3 years, target lesion failure occurred in 4.7% and 7.8% of O-SES and R-ZES groups, respectively (hazard ratio, 0.58; 95% confidence intervals, 0.24-1.41; p = .232 by log-rank test). Secondary endpoints including cardiac death, myocardial infarction, and target lesion revascularization showed no significant differences between the groups. Stent thrombosis occurred in two patients in R-ZES group (0.0% vs. 1.6%, p = .040).

CONCLUSION

This study confirms long-term safety and efficacy of the two stents. We found a trend for lower target lesion failure with O-SES compared to R-ZES, although statistically insignificant.

Time Course of Reendothelialization with Polyzene-F Nanocoated Cobra PzF™ Coronary Stent on Rabbit Iliac Arteries

PURPOSE

Evaluation of reendothelialization with a new thin struts cobalt chromium alloy stent coated with a nano-layer of Polyzene™-F (PzF) in a rabbit iliac artery model.

METHODS

Fifteen stented external rabbit iliac arteries were harvested at Day 7 for electron microscopy analysis following Cobra PzF stents implantation to assess reendothelialization and compare to historical data. Ten additional rabbits were used to assess time course of reendothelialization at 3 and 5 days.

RESULTS

At Day 7, almost complete coverage of endothelial cells was observed with a coverage of 99.54 ± 0.25% of the stented area. No thrombus area was noted. At Day 3, more than half of examined pieces was reendothelialized and reached 78.30 ± 3.7% at Day 5 (p < .01 between each group). All stents were well expanded against the arterial wall and no struts were mal-apposed.

CONCLUSIONS

Reendothelialization was rapid and complete at Day 7. This is the fastest reendothelization process after stenting in this model. No stent occlusion was observed.

Long-term safety of bioresorbable scaffolds: insights from a network meta-analysis including 91 trials

AIMS

The aim of this study was to investigate the long-term safety and efficacy of biodegradable scaffolds and metallic stents.

METHODS AND RESULTS

We analysed a total of 91 randomised controlled trials with a mean follow-up of 3.7 years in 105,842 patients which compared two or more coronary metallic stents or biodegradable scaffolds and reported the long-term clinical outcomes (≥2 years). Network meta-analysis showed that patients treated with the Absorb bioresorbable vascular scaffold (BVS) had a significantly higher risk of definite or probable scaffold thrombosis (ScT) compared to those treated with metallic DES. The risk of very late ScT was highest with the Absorb BVS among comparators. Pairwise conventional meta-analysis demonstrated that the elevated risk of ScT with Absorb BVS compared to cobalt-chromium everolimus-eluting stents was consistent across the time points of ≤30 days (early), 31 days - 1 year (late) and >1 year (very late) ScT. In addition, target lesion failure rates were significantly higher in the Absorb BVS cohort, driven by both increased risk of target vessel myocardial infarction and ischaemia-driven target lesion revascularisation.

CONCLUSIONS

Absorb BVS implantation was associated with increased risk of long-term and very late ScT compared to current-generation metallic DES. The risk of ScT occurred with a rising trend beyond one year.

Comparison of Limus-Eluting and Paclitaxel-Eluting Stents for Coronary Intervention in Patients with Chronic Kidney Disease

Chronic kidney disease (CKD) patients have worse adverse cardiovascular outcomes after percutaneous coronary intervention (PCI). Clinical outcomes comparing a limus-eluting stent (LES) to a paclitaxel-eluting stent (PES) in patients with CKD remain controversial.A systematic search was conducted using PubMed, EMBASE, and Cochrane Library. A pooled odds ratio (OR) and 95% confidence interval (CI) were used to calculate original data. We conducted heterogeneity, quality assessment, and publication bias analyses.A total of 17 trials involving 10,724 patients were included. No significant differences were found regarding target vessel revascularization, target lesion revascularization (TLR), stent thrombosis (ST), myocardial infarction (MI), all-cause mortality, and major adverse cardiac events (MACE) between first-generation LES implantation and PES implantation. Second-generation LES implantation was associated with lower rates of all-cause mortality (OR, 0.56; 95% CI, 0.39-0.82; P = 0.003), MACE (OR, 0.61; 95% CI, 0.38-0.97; P = 0.04), and ST (OR, 0.45; 95% CI, 0.26-0.77; P = 0.004) compared with PES implantation. In all, the long-term all-cause mortality rate was significantly lower after LES implantation than after PES implantation in patients with CKD (OR, 0.78; 95% CI, 0.66-0.93; P = 0.004). However, second-generation LES implantation resulted in a higher rate of TLR (OR, 2.23; 95% CI, 1.53-3.25; P < 0.001) than PES implantation in dialysis patients.In patients with CKD, first-generation LES and PES implantation had comparable mortality and morbidity. Second-generation LES implantation was superior to PES in reducing long-term mortality, MACE, and ST. However, PES may be more effective than LES in dialysis patients.

First-generation versus second-generation drug-eluting stents in patients with chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

Chronic kidney disease (CKD) patients are associated with very high rate of adverse cardiovascular outcomes after drug-eluting stents (DES) implantation. The clinical outcomes of second-generation DES versus first-generation DES in CKD patients remain controversial.

OBJECTIVE

The aim of the current study was to perform a systematic review and meta-analysis to assess the safety and efficacy of second-generation DES versus first-generation DES in CKD patients.

METHODS

A systematical search of databases of PubMed, EMBASE, and Cochrane Library was conducted for eligible studies comparing the clinical outcomes of first-generation DES versus second-generation DES. Sirolimus-eluting and paclitaxel-eluting stents were classified as first-generation DES, and everolimus-eluting, zotarolimus-eluting, and biolimus-eluting stent (BES) were classified as second-generation DES. A pooled odds ratio (OR) and 95% confidence interval (CI) were used to summary the estimates. Heterogeneity, subgroup analysis, sensitivity analysis and publication bias were also performed.

RESULTS

We identified 14 trials involving 9,542 patients with CKD undergoing percutaneous coronary intervention. First-generation DES implantation was associated with higher risk of long-term all-cause mortality (OR, 1.31; 95% CI, 1.02-1.69; P = 0.04; I² = 0%), in stent restenosis (OR, 1.69; 95% CI, 1.14-2.49; P = 0.008; I² = 49%) and stent thrombosis (OR, 1.64; 95% CI, 1.00-2.69; P = 0.05; I² = 49%) compared with second-generation DES implantation. First-generation DES and second-generation DES showed similar efficacy in decreasing risk of repeat revascularization, myocardial infarction (MI), or major adverse cardiac events (MACE) between first-generation and second-generation DES implantation.

CONCLUSIONS

In CKD patients, the use of second-generation DES was associated with lower risk of long-term all-cause mortality, in stent restenosis and stent thrombosis as compared with first-generation DES. No differences were found regarding repeat revascularization, MI, and MACE.

Planned use of GP IIb/IIIa inhibitors is safe and effective during implantation of the Absorb Bioresorbable Vascular Scaffold

Bioresorbable Vascular Scaffolds (BVS) have the potential for adaptive vessel remodeling, restoration of vasomotion, and late luminal enlargement, thus allowing them to circumvent target lesion failures associated with bare metal stents (BMS) and drug-eluting stents (DES). However, recent data has shown a concerning increase in BVS-associated scaffold thrombosis (ScT) compared to DES. Upfront administration of GP IIb/IIIa inhibitors (GPIs) has shown to reduce early stent thrombosis (ST) compared to standard of care in BMS and DES. Since the use of GPIs was limited in BVS studies, the effect of GPIs on the rate of BVS-associated ScT is largely unknown. This is the first study investigating whether a planned use of GPIs during implantation of the Absorb BVS represents a safe and effective strategy in reducing ScT. In a retrospective chart review of 22 patients undergoing PCI with BVS implantation and planned GPI administration, no acute ScT, in-hospital MACE, or in-hospital major/minor bleeding events were observed. Bleeding reduction strategies such as shorter GPI infusion and radial access were implemented. This study provides valuable preliminary evidence on the benefit and safety in using planned GPI administration to reduce the incidence of ScT after implantation of BVS.

Antiplatelet and anticoagulation regimen in patients with mechanical valve undergoing PCI - State-of-the-art review

A common clinical dilemma regarding treatment of patients with a mechanical valve is the need for concomitant antiplatelet therapy for a variety of reasons, referred to as triple therapy. Triple therapy is when a patient is prescribed aspirin, a P2Y12 antagonist, and an oral anticoagulant. Based on the totality of the available evidence, best practice in 2017 for patients with mechanical valves undergoing percutaneous coronary intervention (PCI) is unclear. Furthermore, the optimal duration of dual antiplatelet therapy after PCI is evolving. With better valve designs that are less thrombogenic, the thromboembolic risks can be reduced at a lower international normalized ratio target, thus decreasing the bleeding risk. This review will offer an in-depth survey of current guidelines, current evidence, suggested approach for PCI in this cohort, and future studies regarding mechanical valve patients undergoing PCI.

Novel aspects of antiplatelet therapy in cardiovascular disease

Antiplatelet therapy is a cornerstone in the secondary prophylaxis of adverse cardiovascular events such as myocardial infarction and stroke. The cyclooxygenase inhibitor aspirin remains the most frequently prescribed antiplatelet drug, followed by adenosine diphosphate P2Y12 receptor blockers. Glycoprotein IIb-IIIa antagonists are intravenously available antiplatelet agents preventing platelet-to-platelet aggregation via the fibrinogen receptor. The thrombin receptor inhibitor vorapaxar allows the targeting of yet a third pathway of platelet activation. Despite the advent of novel agents and major advances in antiplatelet treatment over the last decade, atherothrombotic events still impair the prognosis of many patients with cardiovascular disease. Consequently, antiplatelet therapy remains a field of intense research and a large number of studies on its various aspects are published each year. This review article summarizes recent developments in antiplatelet therapy in cardiovascular disease focusing particularly on the duration of dual antiplatelet therapy, new treatment regimens, the role of platelet function testing, and potential future targets of antiplatelet agents.

Are Shorter Durations of Dual Antiplatelet Therapy Acceptable Following Percutaneous Coronary Intervention?

Much debate has centered on whether or not the standard 12-month duration of dual antiplatelet therapy (DAPT) is still necessary postpercutaneous coronary intervention, given recent improvements in stent technology. The benefits of shorter (3-6 months) durations of DAPT include a potential lower risk for bleeding and less patient drug cost and pill burden. Although randomized clinical trials have shown noninferiority for shorter versus longer DAPT regimens in many regards, some endpoints (e.g., myocardial infarction) may still occur less frequently with longer DAPT regimens, particularly in higher risk populations (e.g., acute coronary syndromes). Bleeding risk is either comparable or less with shorter versus longer DAPT regimens. Given the lack of unequivocal data regarding the equality of shorter versus longer DAPT regimens in all patients, there is a growing consensus that an individualized approach is advisable for determining DAPT duration postpercutaneous coronary intervention. Clinical decision aids and updated clinical practice guidelines are available that consider risk:benefit ratios and clinical trial data to assist the clinician in developing a personalized DAPT regimen.

The evolution of coronary stents

INTRODUCTION

Percutaneous coronary intervention (PCI) is 40 years old this year. From its humble beginnings of experimental work, PCI has transitioned over years with coronary artery stenting now a standard medical procedure performed throughout the world. Areas covered: The conversion from plain old balloon angioplasty (POBA) to the present era of drug eluting stents (DES) has been driven by many technological advances and large bodies of clinical trial evidence. The journey to present day practice has seen many setbacks, such as acute vessel closure with POBA; rates of instant restenosis with bare metal stents (BMS) and more recently, high rates of stent thrombosis with bioabsorbable platforms. This work discusses POBA, why there was a need for BMS, the use of inhibiting drugs to create 1^st generation DES, the change of components to 2^nd generation DES, the use of absorbable drug reservoirs and platforms, and possible future directions with Prohealing Endothelial Progenitor Cell Capture Stents. Expert commentary: This paper reviews the evolution from the original pioneering work to modern day practice, highlighting landmark trials that changed practice. Modern day contemporary practice is now very safe based on the latest drug eluting stents and supported by large datasets.

Immediate and 1-year follow-up with the novel nanosurface modified COBRA PzF stent

BACKGROUND

The COBRA PzF coronary stent, which has a unique nano-coating of Polyzene-F, was developed to reduce the risk of stent thrombosis.

AIMS

To report procedural and 1-year clinical outcomes following COBRA PzF coronary stent implantation in a real-world percutaneous coronary intervention (PCI) registry.

METHODS

All patients assigned to treatment with the COBRA PzF in the GCS Axium Rambot Center, Aix-en-Provence, France between February 2013 to June 2014 were prospectively enrolled.

RESULTS

Among 100 patients (71% men, mean±standard error age 71.4±11.0 years), 38% had acute coronary syndromes. The population was consistent with real-world experience and included patients with multiple co-morbidities and 26% with diffuse multivessel disease. A total of 151 lesions were treated with 166 stents, including 26% of lesions with a type B2 or C classification. Pre- and post-procedural quantitative coronary angiography analyses showed a mean acute gain of 2.2±0.2mm. Angiographic success was achieved in all cases. One-year follow-up was available for all patients and the target vessel failure (composite of all-cause mortality, myocardial infarction or target vessel revascularization) rate was 12%, including 2% mortality (end-stage cardiomyopathy), 5% myocardial infarction (five periprocedural myocardial infarctions with isolated troponin elevation without chest pain or Q waves) and 5% target lesion revascularization. There were no cases of definite stent thrombosis.

CONCLUSION

The COBRA PzF stent was safe and effective in routine practice. One-year follow-up was associated with excellent clinical outcomes and compared favourably with current devices. These results are very promising in a real-world population of complex patients, and further study is warranted.

Relationship between optical coherence tomography-defined in-stent neoatherosclerosis and out-stent arterial remodeling assessed by serial intravascular ultrasound examinations in late and very late drug-eluting stent failure

BACKGROUND

Little is known regarding the association between chronological out-stent vessel remodeling and in-stent tissue characteristics of drug-eluting stent (DES) failure. We aimed to evaluate the relationship between serial vessel remodeling after DES implantation and neoatherosclerosis (NA) assessed by optical coherence tomography (OCT) in patients with DES failure.

METHODS

Forty-eight patients with late and very late stent failure after DES implantation, who underwent intravascular ultrasound (IVUS) at both the initial percutaneous coronary intervention and the time of stent failure and OCT imaging at the time of stent failure, were retrospectively investigated. NA on OCT was defined as neointimal formation with the presence of lipids or calcification inside the stents. Lesions were divided into two groups: those with NA and those without NA (NA: n=21; non-NA: n=27). From the serial IVUS examinations, external elastic membrane (EEM) volume and out-stent plaque volume were normalized by stent length and their changes were compared between the two groups.

RESULTS

The NA group showed older stent age [median, 5.1 years (IQR, 4.8-8.3) vs 1.4 years (IQR, 0.8-4.5); p<0.01] and more prevalent sirolimus-eluting stents (SES; 81.0% vs. 29.6%; p<0.01). IVUS findings of the NA group showed a greater serial increase in both normalized EEM volume and normalized out-stent plaque volume (OSPVI) [1.05 (0.41-1.90) vs. 0.11 (-0.64 to 0.80) mm²; p<0.01; and 0.88 (0.57-1.98) vs. 0.12 (-0.41 to 0.78) mm²; p<0.01]. On multivariate analysis, percentage change in OSPVI (OR, 1.07; 95% CI, 1.01-1.14; p=0.02) and SES (OR, 9.78; 95% CI, 2.20-43.40; p<0.01) remained independent predictors of NA.

CONCLUSIONS

NA in late and very late DES failure was associated with out-stent positive vessel remodeling. In addition to SES, out-stent progressive positive remodeling may help predict NA in late and very late DES failure.

Everolimus- versus zotarolimus-eluting stent following percutaneous coronary chronic total occlusion intervention

BACKGROUND

Although studies have demonstrated comparable efficacy and safety profiles of everolimus- and zotarolimus-eluting stents (EES and ZES, respectively) for a broad spectrum of coronary artery diseases, there is paucity of data concerning their safety and efficacy for coronary chronic total occlusions (CTOs). This study compared the clinical performance of EES and ZES following successful percutaneous coronary intervention for CTOs.

METHODS

The cohort included 539 consecutive CTO patients who underwent successful PCI using EES (n=313) and ZES (n=226) between September 2006 and August 2014. The primary outcome was defined as the composite of death, myocardial infarction, and target vessel revascularization.

RESULTS

During a median follow-up of 3.3years, in both groups, the primary outcome occurred in 12.2% of patients. After multivariable adjustment, no significant difference was observed between the two groups in the risk of primary outcome [hazard ratio (HR) 1.03, 95% confidence interval (CI) 0.59-1.79, P=0.930 for ZES compared with EES]. Similarly, there were no significant differences in the risk of death (adjusted HR 0.96, 95% CI 0.43-2.15, P=925), death or myocardial infarction (adjusted HR 0.93, 95% CI 0.46-1.88, P=0.829), and target vessel failure (adjusted HR 0.96, 95% CI 0.51-1.82, P=0.902). The incidence of definite/probable stent thrombosis was relatively low [0% (ZES) vs. 1.0% (EES), P=0.19].

CONCLUSION

No significant differences were observed between EES and ZES in terms of clinical outcomes for coronary CTOs at 3.3years.

Coronary stents and vascular response to implantation: literature review

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

Effect of biodegradable polymer drug-eluting stents versus biocompatible polymer everolimus-eluting stents: a meta-analysis

OBJECTIVE

Biocompatible polymer everolimus-eluting stents (EES) are associated with risk of stent thrombosis (ST); biodegradable polymer drug-eluting stents (BP-DES) were designed to reduce these risks. However, the long-term benefits are not completely clear.

METHOD

We undertook a meta-analysis of randomized studies identified in systematic searches of MEDLINE, EMBASE, and the Cochrane Database. Primary outcome was the risk of ST.

RESULTS

Twelve studies (11,692 patients) were included. Overall, compared with EES, BP-DES were associated with a broadly equivalent risk of definite and probable ST (OR, 0.91; 95% CI, 0.55 to 1.50; P = 0.71; I²= 0.0%), early ST (OR, 2.25; 95% CI, 0.78 to 6.47; P = 0.13; I²= 0.0%), late ST (OR, 3.57; 95% CI, 0.42 to 30.58; P = 0.25; I²= 0.0%) and very late ST (OR, 0.50; 95% CI, 0.05 to 5.52; P = 0.57). Meanwhile, there was no significant difference in all-cause mortality (OR, 1.07; 95% CI, 0.86 to 1.32; P = 0.54; I²= 0.0%), myocardial infarction (OR, 1.07; 95% CI, 0.88 to 1.30; P = 0.47; I²= 0.0%), target vessel revascularization (OR, 1.02; 95% CI, 0.86 to 1.21; P = 0.80; I²= 12.0%), and major adverse cardiac events (OR, 1.04; 95% CI, 0.93 to 1.16; P = 0.53; I²= 0.0%). Furthermore, angiographic data showed that in-stent and in-segment late luminal loss were similar between the two groups.

CONCLUSIONS

Compared with biocompatible polymer EES, biodegradable polymer stents appear to have equivalent clinical benefits.

Paving the way to a bioresorbable technology: Development of the absorb BRS program

Bioresorbable scaffolds (BRS) combine attributes of the preceding generations of percutaneous coronary intervention (PCI) devices with new technologies to result in a novel therapy promoted as being the fourth generation of PCI. By providing mechanical support and drug elution to suppress restenosis, BRS initially function similarly to drug eluting stents. Thereafter, through their degradation, BRS undergo a decline in radial strength, allowing a gradual transition of mechanical function from the scaffold back to the artery in order to provide long term effectiveness similar to balloon angioplasty. The principles of operation of BRS, whether of polymeric or metallic composition, follow three phases of functionality reflective of differing physiological requirements over time: revascularization, restoration, and resorption. In this review, these three fundamental performance phases and the metrics for the nonclinical evaluation of BRS, including both bench and preclinical testing, are discussed. © 2016 Wiley Periodicals, Inc.

Frequency of Stent Thrombosis Risk at 5 Years in Women Versus Men With Zotarolimus-Eluting Compared With Sirolimus-Eluting Stent

The prevalence of factors that are associated with an increased risk of stent thrombosis (ST), including smoking, diabetes mellitus, and small stent size, is different in women and men who underwent percutaneous coronary intervention. Thus, gender may potentially modify the relation between stent type and the incidence of ST during long-term follow-up. We explored the data of Patient Related Outcomes With Endeavor Versus Cypher stenting Trial (PROTECT) to evaluate this hypothesis. PROTECT randomized 2,061 women and 6,648 men who underwent percutaneous coronary intervention for various indications to Endeavor zotarolimus-eluting stenting (E-ZES) or Cypher sirolimus-eluting stenting (C-SES). Dual antiplatelet therapy was prescribed for at least 3 months. Data on study end points were collected until 5 years after randomization, including ST, death, and cardiovascular events. We analyzed end points and treatment effect (E-ZES vs C-SES) in relation to gender. Women were on average 4.7 years older (65.8 vs 61.1), had a higher prevalence of insulin-dependent diabetes mellitus, were less often smokers, and had a shorter total stent length than men. At discharge and throughout follow-up, a slightly lower fraction of women were using dual antiplatelet therapy. During 5-year follow-up, definite or probable ST was observed in 36 women (1.8%) and 152 men (2.4%; log-rank p = 0.15). E-ZES reduced the incidence of ST compared with C-SES in women (hazard ratio 0.58) and men (hazard ratio 0.61), with no evidence of heterogeneity (p = 0.89). In conclusion, in PROTECT, women and men had similar cumulative incidence of ST at 5 years after stent placement. The favorable effect of the study stent E-ZES over C-SES was not modified by gender.

Late and Very Late Stent Thrombosis in the Era of Second-Generation Drug-Eluding Stents

Stent thrombosis is a life-threatening complication of percutaneous coronary intervention that often results in ST-segment myocardial infarction or sudden cardiac death. First-generation drug-eluting stents (DESs) are associated with an increased risk of late and very late stent thrombosis compared with bare- metal stents due to delayed endothelialisation of the stent struts. The second-generation DES design includes a number of improved features (thinner stent struts, fluorinated copolymers, and different anti-proliferative agents) to decrease the risk of late stent thrombosis. Currently, the cobalt-chromium everolimus-eluting stent, a second-generation stent, has the lowest risk of stent thrombosis when compared with the available alternatives. Given the improved design of second-generation stents, a shorter duration of dual antiplatelet therapy of 6 months may be enough to reduce the rate of bleeding complications without increasing the risk of adverse cardiovascular events. Future large-scale randomised trials are required to evaluate the safety and efficacy of third-generation DESs which feature bioresorbable polymers and scaffolds.

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.

Development and Validation of a Prediction Rule for Benefit and Harm of Dual Antiplatelet Therapy Beyond 1 Year After Percutaneous Coronary Intervention

IMPORTANCE

Dual antiplatelet therapy after percutaneous coronary intervention (PCI) reduces ischemia but increases bleeding.

OBJECTIVE

To develop a clinical decision tool to identify patients expected to derive benefit vs harm from continuing thienopyridine beyond 1 year after PCI.

DESIGN, SETTING, AND PARTICIPANTS

Among 11,648 randomized DAPT Study patients from 11 countries (August 2009-May 2014), a prediction rule was derived stratifying patients into groups to distinguish ischemic and bleeding risk 12 to 30 months after PCI. Validation was internal via bootstrap resampling and external among 8136 patients from 36 countries randomized in the PROTECT trial (June 2007-July 2014).

EXPOSURES

Twelve months of open-label thienopyridine plus aspirin, then randomized to 18 months of continued thienopyridine plus aspirin vs placebo plus aspirin.

MAIN OUTCOMES AND MEASURES

Ischemia (myocardial infarction or stent thrombosis) and bleeding (moderate or severe) 12 to 30 months after PCI.

RESULTS

Among DAPT Study patients (derivation cohort; mean age, 61.3 years; women, 25.1%), ischemia occurred in 348 patients (3.0%) and bleeding in 215 (1.8%). Derivation cohort models predicting ischemia and bleeding had c statistics of 0.70 and 0.68, respectively. The prediction rule assigned 1 point each for myocardial infarction at presentation, prior myocardial infarction or PCI, diabetes, stent diameter less than 3 mm, smoking, and paclitaxel-eluting stent; 2 points each for history of congestive heart failure/low ejection fraction and vein graft intervention; -1 point for age 65 to younger than 75 years; and -2 points for age 75 years or older. Among the high score group (score ≥2, n = 5917), continued thienopyridine vs placebo was associated with reduced ischemic events (2.7% vs 5.7%; risk difference [RD], -3.0% [95% CI, -4.1% to -2.0%], P < .001) compared with the low score group (score <2, n = 5731; 1.7% vs 2.3%; RD, -0.7% [95% CI, -1.4% to 0.09%], P = .07; interaction P < .001). Conversely, continued thienopyridine was associated with smaller increases in bleeding among the high score group (1.8% vs 1.4%; RD, 0.4% [95% CI, -0.3% to 1.0%], P = .26) compared with the low score group (3.0% vs 1.4%; RD, 1.5% [95% CI, 0.8% to 2.3%], P < .001; interaction P = .02). Among PROTECT patients (validation cohort; mean age, 62 years; women, 23.7%), ischemia occurred in 79 patients (1.0%) and bleeding in 37 (0.5%), with a c statistic of 0.64 for ischemia and 0.64 for bleeding. In this cohort, the high-score patients (n = 2848) had increased ischemic events compared with the low-score patients and no significant difference in bleeding.

CONCLUSION AND RELEVANCE

Among patients not sustaining major bleeding or ischemic events 1 year after PCI, a prediction rule assessing late ischemic and bleeding risks to inform dual antiplatelet therapy duration showed modest accuracy in derivation and validation cohorts. This rule requires further prospective evaluation to assess potential effects on patient care, as well as validation in other cohorts.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00977938.

Duration of Dual Antiplatelet Therapy: A Systematic Review for the 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

BACKGROUND

The optimal duration of dual antiplatelet therapy (DAPT) after implantation of newer-generation drug-eluting stents (DES) remains uncertain. Similarly, questions remain about the role of DAPT in long-term therapy of stable post-myocardial infarction (MI) patients.

AIM

Our objective was to compare the incidence of death, major hemorrhage, MI, stent thrombosis, and major adverse cardiac events in patients randomized to prolonged or short-course DAPT after implantation of newer-generation DES and in secondary prevention after MI.

METHODS

We used traditional frequentist statistical and Bayesian approaches to address the following questions: Q1) What is the minimum duration of DAPT required after DES implantation? Q2) What is the clinical benefit of prolonging DAPT up to 18 to 48 months? Q3) What is the clinical effect of DAPT in stable patients who are >1 year past an MI?

RESULTS

We reviewed evidence from 11 randomized controlled trials (RCTs) that enrolled 33 051 patients who received predominantly newer-generation DES to answer: A1) Use of DAPT for 12 months, as compared with use for 3 to 6 months, resulted in no significant differences in incidence of death (odds ratio [OR]: 1.17; 95% confidence interval [CI]: 0.85 to 1.63), major hemorrhage (OR: 1.65; 95% CI: 0.97 to 2.82), MI (OR: 0.87; 95% CI: 0.65 to 1.18), or stent thrombosis (OR: 0.87; 95% CI: 0.49 to 1.55). Bayesian models confirmed the primary analysis. A2) Use of DAPT for 18 to 48 months, compared with use for 6 to 12 months, was associated with no difference in incidence of all-cause death (OR: 1.14; 95% CI: 0.92 to 1.42) but was associated with increased major hemorrhage (OR: 1.58; 95% CI: 1.20 to 2.09), decreased MI (OR: 0.67; 95% CI: 0.47 to 0.95), and decreased stent thrombosis (OR: 0.45; 95% CI: 0.24 to 0.74). A risk-benefit analysis found 3 fewer stent thromboses (95% CI: 2 to 5) and 6 fewer MIs (95% CI: 2 to 11) but 5 more major bleeds (95% CI: 3 to 9) per 1000 patients treated with prolonged DAPT per year. Post hoc analyses provided weak evidence of increased mortality with prolonged DAPT. We reviewed evidence from 1 RCT of 21 162 patients and a post hoc analysis of 1 RCT of 15 603 patients to answer: A3): Use of DAPT >1 year after MI reduced the composite risk of cardiovascular death, MI, or stroke (hazard ratio: 0.84; 95% CI: 0.74 to 0.95) but increased major bleeding (hazard ratio: 2.32; 95% CI: 1.68 to 3.21). A meta-analysis and a post hoc analysis of an RCT in patients with stable cardiovascular disease produced similar findings.

CONCLUSIONS

The primary analysis provides moderately strong evidence that prolonged DAPT after implantation of newer-generation DES entails a tradeoff between reductions in stent thrombosis and MI and increases in major hemorrhage. Secondary analyses provide weak evidence of increased mortality with prolonged DAPT after DES implantation. In patients whose coronary thrombotic risk was defined by a prior MI rather than by DES implantation, the primary analysis provides moderately strong evidence of reduced cardiovascular events at the expense of increased bleeding.