Stent thrombosis in 2008: Definition, predictors, prognosis and treatment

[Outpatient coronary angiography and angioplastie/ why, how and for wich patients?]

There is great heterogeneity in lengths of stay in interventional cardiology but the number of outpatient procedures is increasing. The expected benefits of an outpatient procedure are numerous and non-inferiority of this strategy has been demonstrated. Proper selection of patients eligible for this treatment is essential to minimize the risks of unplanned hospitalization and early complications. It is based on clinical, medico-social and organizational criteria. Perfect management of the care pathway based on an organizational unit and a geographical unit is essential.

Early and long-term prognosis in patients with remaining chronic total occlusions after revascularization attempt. A cohort study from the SKEJ-CTO registry

OBJECTIVES

The present study aimed to compare safety and long-term prognosis of patients with chronic total coronary occlusions (CTO) stratified for remaining CTOs after percutaneous coronary intervention (PCI).

DESIGN

The study cohort consisted of patients with coronary artery disease who underwent CTO PCI in a high volume tertiary center from 2009 to 2019 and were registered in Danish high-quality registers. Patients with successful PCI of all CTOs were compared to patients with ≥1 remaining CTO post-procedural. Primary endpoints were analysed using Cox-regression and Kaplan-Meier estimates, and included all-cause mortality, major adverse cardio- and cerebrovascular events (MACCE) and a 30-day safety endpoint.

RESULTS

Procedural success rate was 87.7%, and 76.5% of patients had all CTO(s) opened post-PCI. Safety endpoint occurred in 4.6% of patients, and more frequently in patients with remaining CTO(s) (RD 4.9, 95%CI 0.1, 9.8). All-cause mortality was higher in patients with remaining CTO(s) (Unadjusted HR 1.65, 95% CI 1.03, 2.47, p = .015. Adjusted HR 1.32, 95%CI 0.88-1.99, p = .18) after eight years of follow-up. Risk of MACCE was significantly higher in patients with remaining CTO(s) (Unadjusted HR 1.79, 95% CI 1.34-2.41, p < .001. Adjusted HR 1.51, 95% CI 1.11-2.05, p = .009).

CONCLUSIONS

In our centre, CTO PCI was associated with high success rate and low risk of 30-days complications. Presence of remaining CTO(s) after final revascularization attempt was associated with higher but statistically insignificant long-term mortality but was an independent predictor of MACCE.

Balloon-Assisted Angioplasty for the Treatment of In-Stent Restenosis After Vertebral Artery Ostium Stenting: Experiences From One Single Center

BACKGROUND

Stenting appears to be a safe means of treatment for vertebral artery ostium stenosis with low complication rates and positive long-term effects, but the incidence of in-stent restenosis (ISR) after stenting is high. Different treatment strategies are applied for the revascularization of ISR; however, currently the optional approach is not recommended. The study was designed to investigate the feasibility, safety, and effectiveness of balloon-assisted angioplasty for the treatment of ISR after vertebral artery ostium stenosis.

METHODS

In this study, we included patients from the Department of Neurology, Lishui Hospital of Zhejiang University, who were treated with balloon-assisted angioplasty as a result of suffering from ISR after previously undergoing vertebral artery ostium stenting. We retrospectively analyzed the clinical and functional outcomes of the patients.

RESULTS

From January 2015 to December 2019, 11 patients were included in the study. The technical success rate reached 100% and the average operation time was 73 minutes. The Thrombolysis in Cerebral Infarction Score 2b-3 was acquired in all patients except 1 patient, who was presented with symptoms of hypoperfusion syndrome. The remaining 10 patients did not experience any intraoperative or postoperative complications. No restenosis, new cerebral infarction or transient ischemic attack were reported within 6 months of follow-up.

CONCLUSION

Balloon-assisted angioplasty could be feasible for the treatment of ISR after vertebral artery ostium stenting, however, more research is needed to confirm this.

Novel insights into clinical characteristics and in-hospital outcomes of patients undergoing percutaneous coronary intervention in Vietnam

BACKGROUND

Little is known about percutaneous coronary intervention (PCI) practices and outcomes in low-and middle-income nations, despite its rapid uptake across Asia. For the first time, we report on clinical characteristics and in-hospital outcomes for patients undergoing PCI at a leading cardiac centre in Vietnam.

METHODS

Information on characteristics, treatments, and outcomes of patients undergoing PCI was collected into the first PCI registry through direct interviews using a standardised form, medical record abstraction, and reading PCI imaging data on secured disks. Subgroup analysis was also conducted to explore gender differences.

RESULTS

Between September 2017 and May 2018, 1022 patients undergoing PCI were recruited from a total of 1041 procedures. The mean age was 68.3 years and two thirds were male. While 54.4% of patients presented with acute coronary syndromes, the rate of ST-elevation myocardial infarction was 14.5%. The majority of lesions were classified as type B2 and C and the radial artery was the most common access location for PCI (79.2%). The use of drug-eluting stents was universal and the angiographic success rate was 99.4%. Cardiac complications following PCI were rare with the exception of major bleeding (2.0%). Female patients were older with relatively more comorbidities and a higher incidence of major bleeding than males (p < 0.05).

CONCLUSIONS

Findings of this study provide an opportunity to benchmark current PCI practices in Vietnam, identify possible care gaps and potentially inform the adoption of treatment guidelines as well as use of prevention strategies.

Endovascular Metal Devices for the Treatment of Cerebrovascular Diseases

Cerebrovascular disease involves various medical disorders that obstruct brain blood vessels or deteriorate cerebral circulation, resulting in ischemic or hemorrhagic stroke. Nowadays, platinum coils with or without biological modification have become routine embolization devices to reduce the risk of cerebral aneurysm bleeding. Additionally, many intracranial stents, flow diverters, and stent retrievers have been invented with uniquely designed structures. To accelerate the translation of these devices into clinical usage, an in-depth understanding of the mechanical and material performance of these metal-based devices is critical. However, considering the more distal location and tortuous anatomic characteristics of cerebral arteries, present devices still risk failing to arrive at target lesions. Consequently, more flexible endovascular devices and novel designs are under urgent demand to overcome the deficiencies of existing devices. Herein, the pros and cons of the current structural designs are discussed when these devices are applied to the treatment of diseases ranging broadly from hemorrhages to ischemic strokes, in order to encourage further development of such kind of devices and investigation of their use in the clinic. Moreover, novel biodegradable materials and drug elution techniques, and the design, safety, and efficacy of personalized devices for further clinical applications in cerebral vasculature are discussed.

Outcomes and safety of same-day discharge after percutaneous coronary intervention: A 10-year single-center study

AIMS

Same-day discharge (SDD) after percutaneous coronary intervention (PCI) was safe and cost-effective in randomized and observational studies but faces limited acceptance due to concerns about early adverse events. Our aim was to evaluate early outcomes after SDD PCI in a high-volume urban PCI center over 10 years.

METHODS AND RESULTS

From 2007 to 2016, 1,635 unselected patients had PCI at our ambulatory cardiac care unit, mainly for stable ischemic heart disease (SIHD). Among them, 1,073 (65.6%), most of whom underwent ad hoc PCI, were discharged on the same day and 562 (34.4%) were admitted, for adverse events during PCI (n = 60) or within the next 4-6 hr (n = 52) or chiefly due to physician preference (n = 450). In the SDD group, radial access was used in 98.5% of patients; 36% and 15% of patients had two- and three-vessel disease, respectively; and two-vessel PCI was performed in 11% of patients. No MACCEs (death, myocardial infarction, stroke, urgent repeat PCI/CABG, and major vascular complications) occurred within 24 hr post-discharge. Two patients were readmitted on the next day for chest pain but did not require repeat PCI.

CONCLUSION

SDD after successful PCI without complications within the next 4-6 hr is safe and feasible in most patients with SIHD. Among 1,035 SDD patients treated over 10 years, only two required readmission, and none experienced major cardiac adverse events such as death or stent thrombosis. SDD is safe for the patient and cost-effective for the healthcare system and should be implemented more widely.

Balloon-expandable stent angioplasty in the treatment of vertebral artery stenosis in the V2 segment

Introduction

Vertebral artery stenosis is a major cause of posterior circulation ischemia in the elderly. There is not a clear consensus on the optimal therapeutic approach for symptomatic extracranial vertebral artery stenosis.

Aim

To evaluate the feasibility and efficacy of balloon-expandable stent angioplasty in the treatment of vertebral artery stenosis in the V2 segment.

Material and methods

Five patients with vertebral artery stenosis (V2 segment) and treatment of percutaneous transluminal stenting from July 2009 to June 2014 were retrospectively evaluated. All patients underwent color Doppler, transcranial color Doppler (TCD), CT angiography (CTA) and cerebral digital subtraction angiography (DSA) preoperatively. Whether there was osseous oppression was determined according to neck computed tomography (CT) and CTA. After the surgery, angiography was performed to determine if there was infarction or bleeding in the intracranial vertebral artery, basilar artery and posterior cerebral artery. The surgical parameters, residual stenosis, complications, etc. were recorded and evaluated. The patients were followed up accordingly.

Results

Five patients (3 males, 2 females; average age of 66 ±4.2, range of 54–75) were enrolled in the study. Balloon-expandable stents were successfully implanted in the 5 patients. The mean residual stenosis after the balloon-expandable stenting (preoperative: average, 87.0 ±6.6%, range: 75–93%) was 12.6 ±7.8% (range: 5–25%). The clinical symptoms disappeared or receded. No serious complications occurred.

Conclusions

The balloon-expandable stent angioplasty seemed to be feasible and efficacious in treating vertebral artery stenosis in the V2 segment. Further study with a large sample size is needed.

Patients with symptoms and characteristics consistent with obstructive sleep apnea are at a higher risk for acute and subacute stent thrombosis after percutaneous coronary stent implantation: a single-center case-control study

Background

To determine if obstructive sleep apnea (OSA) is a risk factor for early stent thrombosis (EST; within 30 days) after percutaneous coronary intervention (PCI).

Methods

This case–control study involved 23 patients with angiographically confirmed EST after PCI (case group) and 92 PCI patients (control group) who did not develop stent thrombosis during a 2-year follow-up. Patients with symptoms and characteristics consistent with OSA (hereinafter referred to as OSA) were identified using the Berlin questionnaire, and the general characteristics of the patients and their treatments as well as outcomes were recorded. The odds ratios (ORs) for OSA were calculated. Additionally, the association between OSA and EST in patients with different conventional cardiovascular risk factors was analyzed.

Results

The crude OR for OSA was 4.17 (95% confidence interval [CI]: 1.60–10.84, P = 0.003). After adjusting for other risk factors of EST, the OR for OSA remained significant. In participants with no or one conventional cardiovascular disease risk factor, we found a significant association between OSA and EST (OR: 17.00, 95% CI: 2.33–124.19, P = 0.005).

Conclusion

OSA is an independent risk factor for EST. This conclusion was further supported by the finding that in patients with few conventional cardiovascular risk factors, the contribution of OSA to EST was more obvious.

A risk scoring system to predict coronary stent thrombosis

OBJECTIVE

Stent thrombosis (ST) is a potentially life-threatening complication of percutaneous coronary intervention (PCI). We aimed to develop a scoring system to predict the risk of ST following PCI.

RESEARCH DESIGN AND METHODS

Odds ratios (ORs) for risk factors associated with ST were identified from a meta-analysis based on a systematic literature review, and through consensus expert opinion (Delphi-RAND method). The combined ORs were used to calculate risk scores for acute (within 24 hours), early (within 30 days) and late (31 days to 1 year) ST. Risk scores were validated against patient-level data from the TRITON-TIMI 38 study. Twenty risk factors were identified.

RESULTS

The most highly predictive factor for early and late ST was "incomplete duration of dual antiplatelet therapy". Derived total risk scores ranged from 0 to 22 for acute and early ST, and from 0 to 20 for late ST. Increasing scores were associated with an increasing risk of ST when applied to trial data. Model discrimination was 0.60 (p = .0028), 0.67 (p < .0001) and 0.66 (p < .0001) for acute, early and late ST respectively, indicating good discriminatory power for predicting ST. Key limitations included a lack of published data on acute ST, resulting in a risk score for this time point being based predominantly on expert opinion, and that it was not possible to map all risk factors to variables collected in the TRITON-TIMI 38 study.

CONCLUSION

Our weighted scoring system may help to stratify ST risk and individualize antiplatelet therapy in patients undergoing PCI.

Spontaneous hematoma in the setting of dual anti-platelet therapy with ticagrelor: A case report

A 69-year-old male patient was admitted to hospital because a lump was discovered, accompanied with pain lasting 5 h under his right scapula. Two months earlier, he had undergone a double-stent insertion operation due to lesions on the end of the left main coronary artery, the opening of left circumflex artery, and the opening of the anterior descending branch. After the operation, he was administered with dual anti-platelet therapy (DAPT) with aspirin and ticagrelor and was diagnosed with hematoma under his right scapula through ultrasonic inspection. It was established that no other factor, except DAPT, was responsible for his spontaneous hematoma.

Biocompatibility of Coronary Stents

Cardiovascular disease is the dominant cause of mortality in developed countries, with coronary artery disease (CAD) a predominant contributor. The development of stents to treat CAD was a significant innovation, facilitating effective percutaneous coronary revascularization. Coronary stents have evolved from bare metal compositions, to incorporate advances in pharmacological therapy in what are now known as drug eluting stents (DES). Deployment of a stent overcomes some limitations of balloon angioplasty alone, but provides an acute stimulus for thrombus formation and promotes neointimal hyperplasia. First generation DES effectively reduced in-stent restenosis, but profoundly delay healing and are susceptible to late stent thrombosis, leading to significant clinical complications in the long term. This review characterizes the development of coronary stents, detailing the incremental improvements, which aim to attenuate the major clinical complications of thrombosis and restenosis. Despite these enhancements, coronary stents remain fundamentally incompatible with the vasculature, an issue which has largely gone unaddressed. We highlight the latest modifications and research directions that promise to more holistically design coronary implants that are truly biocompatible.

Clinical presentations, antiplatelet strategies and prognosis of patients with stent thrombosis: an observational study of 140 patients

Background

Until now there has been scarce evidence regarding an optimal antiplatelet strategy and clinical outcomes for patients who had suffered from stent thrombosis (ST).

Methods and Results

140 patients who suffered from stent thrombosis were prospectively registered. Patients received dual (aspirin and 150 mg clopidogrel, N = 66) or triple (additional cilostazol, N = 74) antiplatelet therapy at the physician’s discretion. Thereafter platelet reactivity and one year clinical outcomes were analyzed. The primary outcome included the composite of cardiac death, non-fatal myocardial infarction (MI) or stroke at one year,which developed in 41 (29.3%) patients, consisting of 31 (22.1%) cardiac death, 9 (6.4%) non-fatal MI and 1 (1.4%) stroke. Recurrent definite and probable ST according to ARC definition was observed in 8 (5.7%) and 14 (10.0%) patients, respectively. Triple therapy was associated with significantly lower platelet reactivities (50.2±17.8, % vs. 59.6±17.2, %, P = 0.002) compared to high dose dual antiplatelet therapy. However, the incidence of primary events (24.3% vs. 34.8%, P = 0.172) did not differ between triple and dual antiplatelet therapies. High on-treatment platelet reactivity (HR: 8.35, 95% CI: 2.234∼30.867, P = 0.002) and diabetes (HR: 3.732, 95% CI: 1.353∼10.298, P = 0.011) were independent predictors of primary events.

Conclusions

Patients who suffered from stent thrombosis have a poor prognosis even after revascularization with intensive antiplatelet therapy. Triple antiplatelet therapy was more effective in reducing on-treatment platelet reactivity, compared to high dose dual antiplatelet therapy.

Stent thrombosis: an overview

Stent thrombosis is a challenging problem following percutaneous coronary intervention that can lead to serious clinical consequences, such as death and acute myocardial infarction. Its pathophysiology is not yet completely known, and there are several causes suggested, such as incomplete stent endothelization, presence of polymers and late incomplete stent apposition. One of the main predictors is the early discontinuation of dual antiplatelet therapy. Stent improvements related to their design, with more friendly metallic platforms, thinner biocompatible or biodegradable polymers, absence of polymers, and even stents manufactured with bioabsorbable materials, could make the percutaneous procedure much safer and effective, allowing its application in increasingly complex anatomic and clinical scenarios, with low thrombosis rates.

Extracellular matrix molecules facilitating vascular biointegration

All vascular implants, including stents, heart valves and graft materials exhibit suboptimal biocompatibility that significantly reduces their clinical efficacy. A range of biomolecules in the subendothelial space have been shown to play critical roles in local regulation of thrombosis, endothelial growth and smooth muscle cell proliferation, making these attractive candidates for modulation of vascular device biointegration. However, classically used biomaterial coatings, such as fibronectin and laminin, modulate only one of these components; enhancing endothelial cell attachment, but also activating platelets and triggering thrombosis. This review examines a subset of extracellular matrix molecules that have demonstrated multi-faceted vascular compatibility and accordingly are promising candidates to improve the biointegration of vascular biomaterials.

The antithrombotic management of patients on oral anticoagulation undergoing coronary stent implantation: an update

Triple therapy (TT) of warfarin, aspirin, and clopidogrel is currently recommended as the optimal antithrombotic treatment in patients on long-term oral anticoagulation (OAC) for clinical conditions at moderate-high thromboembolic risk, such as moderate-high risk atrial fibrillation, mechanical heart valve, cardiogenic embolism, etc., who undergo coronary stent implantation. While being recognized as the most effective treatment for preventing major adverse cardiac events, stent thrombosis and stroke, TT is associated with an increased risk of bleeding, which apparently increases as the duration of TT is prolonged. Available evidence, however, is flawed by important limitations, including the limited size and retrospective design of most of the studies, as well as, the underreporting of the treatment that was actually ongoing at the time of an event. Recent data derived from larger, prospective studies have broadened and strengthened the recommendations that have been earlier issued by Scientific Associations. While confirming the overall superior net clinical benefit of TT in patients at moderate-high thromboembolic risk, recent data suggest that: (1) TT is likely associated with minor rather than major bleeding complications, and (2) accurate stratification of thromboembolic and bleeding risk may allow optimization of the antithrombotic treatment at discharge. Therefore, while still awaiting well designed, prospective, randomized trials, current data indicate that TT is the treatment of choice for patients on OAC at moderate-high thromboembolic risk, provided that meticulous review is frequently carried out in order to minimize and to detect early bleeding complications, while discontinuation of OAC and substitution with dual antiplatelet treatment is warranted in low-risk patients.

Recurrent angina after coronary angioplasty: mechanisms, diagnostic and therapeutic options

Recurrent angina in patients who underwent percutaneous coronary intervention is defined as recurrence of chest pain or chest discomfort. Careful assessment is recommended to differentiate between non-cardiac and cardiac causes. In the case of the latter, recurrent angina occurrence can be related to structural ('stretch pain', in-stent restenosis, in-stent thrombosis, incomplete revascularization, progression of coronary atherosclerosis) or functional (coronary micro-vascular dysfunction, epicardial coronary spasm) causes. Even though a complete diagnostic algorithm has not been validated, ECG exercise testing, stress imaging and invasive assessment of coronary blood flow and coronary vaso-motion (i.e. coronary flow reserve, provocation testing for coronary spasm) may be required. When repeated coronary revascularization is not indicated, therapeutic approaches should aim at targeting the underlying mechanism for the patient's symptoms using a variety of drugs currently available such as beta-blockers, calcium-channel blockers, ivabradine or ranolazine.

Clopidogrel dilemma for orthopaedic surgeons

BACKGROUND

Patients medicated with clopidogrel who require orthopaedic surgery present a particular challenge. Whether in an emergency or elective situation the orthopaedic surgeon must balance the risks of ceasing clopidogrel versus the risk of increased bleeding that dual antiplatelet therapy generates.

METHOD

This paper reviews the current published evidence regarding the risks of continuing clopidogrel, the risks of discontinuing clopidogrel and associated considerations such as venous thromboprophylaxis.

RESULTS

Little good quality evidence exists in regard to perioperative clopidogrel for orthopaedic surgery. Available evidence across non-cardiac and cardiac surgery were assessed and presented in regards to current practices, blood loss for orthopaedic operations, risks when continuing clopidogrel, risks of stopping clopidogrel and also the consideration of venous thromboembolism.

CONCLUSIONS

The patients at greatest risk, when discontinuing clopidogrel therapy, are those with drug eluting stents who may be at risk of stent thrombosis. Where possible, efforts should be made to continue clopidogrel therapy through the perioperative period, taking precautions to minimize bleeding. If the risk of bleeding is too high, antiplatelet therapy must be reinstated as soon as considered reasonable after surgery. In addition, patients on clopidogrel who sustain a fall or other general trauma need to be carefully assessed because of the possibility of occult bleeding, such as into the retroperitoneal space. Until more definitive evidence becomes available, this review aims to provide a guide for the orthopaedic surgeon in dealing with the difficult dilemma of the patient on clopidogrel therapy, recommending that orthopaedic surgeons take a team approach to assess the individual risks for all patients and consider continuation of clopidogrel therapy perioperatively where possible.

Impact of Exercise-based Cardiac Rehabilitation on In-stent Restenosis with Different Generations of Drug Eluting Stent

Objective

To compare the rate of restenosis between a cardiac rehabilitation (CR) group and a control group within three different generations of drug eluting stents (DES).

Method

Patients who received DES due to an acute coronary syndrome were included. They were divided into a CR group and a control group. The CR group received six to eight weeks of early cardiac rehabilitation program in a hospital setting, and sustained a self-exercise program for six months in a community. The control group was instructed to exercise by themselves after leaving the hospital. Nine months after the first onset of disease, we implemented a coronary angiography and compared the two groups. In addition, we divided the patients into three subgroups according to the generation of DES, and compared the rate of restenosis between the CR group and control group within these three subgroups.

Results

At 9 months, in-stent restenosis, measured as an in-segment late luminal loss (LLL) of the stented coronary area, was smaller in the CR group (n=52) 0.16±0.42 mm compared to the control group (n=51) 0.39±0.78 mm (p<0.05). A reduction of LLL in the CR group compared to the control group was consistent among the three different generations of DES.

Conclusion

The CR program is strongly associated with a significant reduction in LLL in the stented coronary segments, regardless of the generation of DES.

Promises and challenges of pharmacogenetics: an overview of study design, methodological and statistical issues

Pharmacogenetics is the study of inherited variation in drug response. The goal of pharmacogenetics is to develop novel ways of maximizing drug efficacy and minimizing toxicity for individual patients. Personalized medicine has the potential to allow for a patient's genetic information to predict optimal dosage for a drug with a narrow therapeutic index, to select the most appropriate pharmacological agent for a given patient and to develop cost-effective treatments. Although there is supporting evidence in favour of pharmacogenetics, its adoption in clinical practice has been slow because of sometimes conflicting findings among studies. This failure to replicate findings may result from a lack of high-quality pharmacogenetic studies, as well as unresolved methodological and statistical issues. The objective of this review is to discuss the benefits of incorporating pharmacogenetics into clinical practice. We will also address outstanding methodological and statistical issues that may lead to heterogeneity among reported pharmacogenetic studies and how they may be addressed.

[Decreasing incidence of stent thrombosis]

Stent thrombosis (ST) remains a major pitfall of stent implantation in contemporary percutaneous coronary intervention (PCI) leading to high rates of death and non-fatal myocardial infarction. Many predictors of ST have been reported worldwide but the strongest have to be highlighted regarding the catastrophic prognosis of such an event. Because platelet aggregation has a pivotal role in ST pathogenesis, the new antiplatelet regimens combining aspirin and P2Y12 receptor inhibitors have led to a remarkable decrease in the ST incidence, especially in the setting of acute coronary syndrome (ACS). In this article, our purpose is to review the evolution of ST incidence since first stent use in PCI. We will also overview the main predictors of ST focusing on ACS and clopidogrel low response.

Duration of dual antiplatelet therapy after percutaneous coronary intervention with drug-eluting stent implantation: a review of the current guidelines and literature

Dual antiplatelet therapy is the mainstay of medical treatment after percutaneous coronary intervention regarding the risk of stent thrombosis occurrence. Since the beginning of the stenting era, antiplatelet regimens have evolved according to the emerging and widespread diffusion of new devices and more challenging indications for their use. In the past years, concerns have been raised about the safety of drug-eluting stent implantation with regard to late and very late stent thrombosis. Thus, the length of dual antiplatelet therapy has been progressively increased with marked individual and local differences. However, prolonged antiplatelet therapy leads to increased risk of bleeding, especially in the setting of surgical procedures, traumas, and/or other diseases. To date, the exact duration of dual antiplatelet therapy after drug-eluting stent implantation is still debated in the literature. The aim of this article is to review the literature and the current guidelines on the risks and benefits of pursuing dual antiplatelet therapy after percutaneous coronary intervention with drug-eluting stent implantation.

Head-to-head comparison of early vessel healing by optical coherence tomography after implantation of different stents in the same patient

OBJECTIVES

Strut coverage represents the most powerful morphometric predictor of stent thrombosis and the best surrogate indicator of endothelization. The aim of this study was to get new insights on temporal patterns of vessel healing after stenting with different types of stent.

METHODS

Optical coherence tomography (OCT) was used to investigate the early strut coverage of lesions treated with CATANIA (CAT) stent, drug-eluting stent (DES) or cobalt-chromium bare metal stent (BMS). Two cohorts of 10 and 24 patients underwent OCT follow-up at 7-10 and 28-32 days after stenting, respectively. In each cohort, patients were randomly assigned to receive a CAT stent in one lesion and a BMS or a DES in a separate lesion.

RESULTS

A total of 7975 and 8406 struts were analyzed for the comparisons of CAT stent vs. DES and CAT stent vs. BMS at 7-10 days, respectively. A total of 21 123 and 25 069 struts were analyzed for the comparisons of CAT stent vs. DES and CAT stent vs. BMS at 28-32 days, respectively. At 7-10 days, the CAT stent showed higher coverage rates compared with DES (90.0 vs. 85.9%, P < 0.0001) and BMS (90.2 vs. 83.6%, P < 0.0001). Similarly, at 28-32 days, the coverage rate was higher with CAT stent compared with DES (97.7 vs. 90.5%, P < 0.0001) and BMS (97.2 vs. 96.5%, P < 0.0001).

CONCLUSION

The CAT stent yields quicker and more complete strut coverage than DES and BMS in the early phases of vessel healing following stent implantation.

Effect of cilostazol on optimized standard antiplatelet therapy in a patient with a cytochrome P450 2C19 *2/*2 genotype

A 54-year-old man with acute coronary syndrome underwent primary percutaneous coronary intervention (PCI) to implant a bare metal stent. Three weeks later, a subclinical in-stent thrombus was found at staged PCI despite dual antiplatelet therapy with aspirin and clopidogrel. Platelet function tests revealed high post-treatment platelet reactivity, indicating an inadequate response to clopidogrel. The patient's cytochrome P450 2C19 genotype was *2/*2. Cilostazol at 200 mg/day was initiated in addition. Three months later, platelet inhibition was enhanced, and no thrombus was detectable by coronary angiography. Our experience suggests that triple antiplatelet therapy with cilostazol as well as aspirin and clopidogrel could prevent stent thrombosis with improved clopidogrel responsiveness.

The immobilization of recombinant human tropoelastin on metals using a plasma-activated coating to improve the biocompatibility of coronary stents

Current endovascular stents have sub-optimal biocompatibility reducing their clinical efficacy. We previously demonstrated a plasma-activated coating (PAC) that covalently bound recombinant human tropoelastin (TE), a major regulator of vascular cells in vivo, to enhance endothelial cell interactions. We sought to develop this coating to enhance its mechanical properties and hemocompatibility for application onto coronary stents. The plasma vapor composition was altered by incorporating argon, nitrogen, hydrogen or oxygen to modulate coating properties. Coatings were characterized for 1) surface properties, 2) mechanical durability, 3) covalent protein binding, 4) endothelial cell interactions and 5) thrombogenicity. The N(2)/Ar PAC had optimal mechanical properties and did not delaminate after stent expansion. The N(2)/Ar PAC was mildly hydrophilic and covalently bound the highest proportion of TE, which enhanced endothelial cell proliferation. Acute thrombogenicity was assessed in a modified Chandler loop using human blood. Strikingly, the N(2)/Ar PAC alone reduced thrombus weight by ten-fold compared to 316L SS, a finding unaltered with immobilized TE. Serum soluble P-selectin was reduced on N(2)/Ar PAC and N(2)/Ar PAC + TE (p < 0.05), consistent with reduced platelet activation. We have demonstrated a coating for metal alloys with multifaceted biocompatibility that resists delamination and is non-thrombogenic, with implications for improving coronary stent efficacy.

Antithrombotic management of patients on oral anticoagulation undergoing coronary artery stenting

Patients on oral anticoagulation (OAC), who are referred for coronary artery stenting account for about 5% of the whole population undergoing percutaneous coronary intervention (PCI). Although relatively small, this patient subset poses particular problems owing to the need to balance carefully the risk of bleeding against the risk of stent thrombosis and thromboembolism. Triple therapy (TT) of OAC, aspirin and clopidogrel appears as the most effective for prevention of stent thrombosis and thromboembolism. However, an increased incidence of major bleeding is to be expected during follow-up. Therefore, TT should be prolonged for as short a time as possible, and implantation of drug-eluting stents avoided. Frequent monitoring of international normalized ratio is also warranted, and the intensity of OAC should be targeted at the lower limit of the therapeutic range. Gastric protection should also be considered for all patients on medium- to long-term TT, owing to the observed highest incidence of bleeding at the gastrointestinal site. Peri-procedural management is cumbersome, and a substantial incidence of in-hospital major bleeding has been reported. Since this latter is more related to procedural variables than to TT itself, choice of radial access, avoidance of glycoprotein IIb/IIIa inhibitors, and preference for not interrupting effective OAC should be implemented. However, the evidence on which the recommendations for managing this patient subset are based is limited and of relative poor quality. While waiting for the results of ongoing, large prospective studies that are aimed at conclusively determining optimal medium- to long-term antithrombotic treatment, the official recommendations issued by the Working Group on Thrombosis of the European Society of Cardiology on the management of patients on OAC undergoing PCI with stenting should followed.

Drug-eluting stents: issues of late stent thrombosis

In in-stent restenosis, drug-eluting stents are superior compared with bare metal stents. However, there are concerns about safety because of the reports of increased risk of late and very late stent thrombosis. Stent thrombosis remains a major pitfall in contemporary percutaneous coronary intervention, leading to high rates of death and nonfatal myocardial infarction. A new standardized definition of stent thrombosis was established to provide consistency in the reporting of this complication and to enable accurate and reliable data to be described for both types of stents, bare metal and drug-eluting. This new consensual definition reflects a large amount of new data reported in the literature. New generations of drug-eluting stents with novel polymers, antiproliferative drugs, and improved platforms are now approved and available for use. In this article, the authors provide a critical appraisal of the safety of different drug-eluting stents based on the published clinical data focusing on late and very late stent thrombosis.