Acute and subacute stent thrombosis after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: incidence, predictors and clinical outcome

The everolimus eluting Synergy MegatronTM drug-eluting stent platform: Early outcomes from the European Synergy MegatronTM Implanters' Registry

BACKGROUND

The Synergy MegatronTM is an everolimus-drug eluting stent that may offer advantages in the treatment of aorto-ostial disease and large proximal vessels.

AIMS

To report the short- to medium-term clinical outcomes from the European Synergy MegatronTM Implanters' Registry.

METHODS

This registry was an investigator-initiated study conducted at 14 European centers. The primary outcome was target lesion failure (TLF), defined as the composite of cardiovascular death, target vessel myocardial infarction (MI), and target lesion revascularisation.

RESULTS

Five hundred seventy-five patients underwent PCI with MegatronTM between 2019 and 2021. Patients were 69 ± 12 years old, 26% had diabetes mellitus, 24% had moderate-severe left ventricular impairment and 59% presented with an acute coronary syndrome. 15% were deemed prohibitively high risk for surgical revascularisation. The target vessel involved the left main stem in 55%, the ostium of the RCA in 13% and was a true bifurcation (Medina 1,1,1) in 50%.  At 1 year, TLF was observed in 40 patients, with 26 (65%) occurring within the first 30 days. The cumulative incidence of TLF was 4.5% at 30 days and 8.6% (95% CI 6.3-11.7) at 1 year. The incidence of stent thrombosis was 0.5% with no late stent thromboses. By multivariate analysis, the strongest independent predictors of TLF were severe left ventricular impairment (HR 3.43, 95% CI: 1.67-6.76, p < 0.001) and a target vessel involving the left main (HR 4.00 95% CI 1.81-10.15 p = 0.001).

CONCLUSIONS

Use of the Synergy MegatronTM everolimus eluting stent in a 'real-world' setting shows favorable outcomes at 30 days and 1 year.

Double the Trouble - One Infarction After Another: A Case Report of Two Consecutive ST-Segment Elevation Myocardial Infarctions in Two Different Coronary Arteries

In multi-vessel coronary artery disease, concomitant ST-segment elevation myocardial infarction (STEMI) in simultaneous two culprit lesions have been rarely reported. In this regard, the recurrence in a short period of time of a STEMI in a different coronary artery is also rare. We describe the case of a 56-year-old male smoker, who was presented with an anterior STEMI. The coronary angiography demonstrated a significant lesion in the left main coronary (LMC) and an occlusion of the left anterior descending artery (LAD), and was referred for surgery. Four days later, he experienced symptoms of acute ischemia of the inferior territory. A newly formed culprit lesion of the circumflex artery (Cx) was detected and benefited from angioplasty. The patient expired the next day from sudden arrythmia. This case report shows two consecutive STEMI situations in separate coronary arteries, which commonly can occur in atherosclerotic patients with very poor prognosis.

Rescue stenting after the failure of mechanical thrombectomy to treat acute intracranial atherosclerotic occlusion

Background

Acute ischemic stroke (AIS) with intracranial large vessel occlusion (LVO) is refractory to reperfusion because of the underlying intracranial atherosclerosis (ICAS), and this condition often requires salvage methods such as balloon angioplasty and rescue stenting (RS). In this study, we investigated the short-term outcomes of RS after failed mechanical thrombectomy (MT) for the treatment of acute intracranial atherosclerotic occlusion.

Methods

We retrospectively evaluated the clinical data of 127 patients who underwent MT for acute intracranial atherosclerotic occlusion in our hospital between August 2018 and January 2022. The degree of recanalization was evaluated immediately after the treatment by Modified Thrombolysis in Cerebral Infarction (mTICI). The modified Rankin Scale (mRS) was used 90 days after treatment to evaluate the neurological functions. In addition, the incidence of symptomatic intracranial hemorrhage (sICH) and postoperative mortality within 90 days of treatment were calculated.

Results

Among the 127 patients, 86 patients (67.7%) had revascularization (mTICI 2b-3) immediately after MT (non-RS group), and RS was performed in 41 patients (32.3%) after MT failure (RS group). No difference in the sICH rate was observed between the two groups (17.1 vs. 16.3%, p = 0.91). There was a slightly higher mortality rate in the RS group (14.6 vs. 12.8%, p = 0.71); however, the difference was not significant. There was no difference in the proportion of patients in the RS and non-RS groups who had a 90-day mRS score of 0-2 (48.8 vs. 52.3%, p = 0.76).

Conclusions

Rescue stenting after MT failure might be a feasible rescue modality for treating acute intracranial atherosclerotic occlusion.

Periprocedural Antithrombotic Treatment in Complex Percutaneous Coronary Intervention

ABSTRACT

In recent years, the management of complex lesions in patients undergoing percutaneous coronary intervention (PCI) constitutes a field of high interest and concern for the interventional cardiology. As more and more studies demonstrate the increased hazard of ischemic events in this group of patients, it is of paramount importance for the physicians to choose the optimal periprocedural (pre-PCI, during-PCI and post-PCI) antithrombotic treatment strategies wisely. Evidence regarding the safety and efficacy of current anticoagulation recommendation, the possible beneficial role of the pretreatment with a potent P2Y12 inhibitor in the subgroup of patients with non-ST segment elevation myocardial infarction with complex lesions, and the impact of a more potent P2Y12 inhibitor in individuals with stable coronary artery disease undergoing complex PCI are needed. This will provide and serve as a guide to clinicians to deploy the maximum efficacy of the current choices of antithrombotic therapy, which will lead to an optimal balance between safety and efficacy in this demanding clinical scenario.

Frequency, Etiology, and Impact of Unplanned Repeat Coronary Angiography After ST-Elevation Myocardial Infarction

Unplanned repeat coronary angiography (CAG) after balloon angioplasty for ST-elevation myocardial infarction (STEMI) was common before the advent of coronary stenting. Limited data are available regarding the role of unplanned repeat CAG in contemporary percutaneous coronary intervention (PCI) for STEMI. Therefore, we analyzed a large, 2-center prospective STEMI registry (January 2011 to June 2020) stratified by the presence or absence of unplanned repeat CAG during index hospitalization. Patients with planned CAG for staged PCI or experimental drug administration were excluded. Among 3,637 patients with STEMI, 130 underwent unplanned repeat CAG (3.6%) during index hospitalization. These patients were more likely to have cardiogenic shock (16% vs 9.8%, p = 0.021), left anterior descending culprit (44% vs 31%, p <0.001), lower left ventricular ejection fraction (45% vs 52%, p <0.001), and higher peak troponin levels (22 vs 8 ng/ml, p <0.001) than those without repeat CAG. At repeat CAG, 80 patients had a patent stent (62%) including 65 requiring no further intervention (50%) and 15 who underwent intervention on a nonculprit lesion (12%). Only 32 patients had stent thrombosis (25%). Repeat CAG was associated with a higher incidence of recurrent MI (19% vs 0%, p <0.001) and major bleeding (12% vs 4.5%, p <0.001), yet similar in-hospital mortality (7% vs 6.4%, p = 0.93) than those without repeat CAG. In conclusion, in the era of contemporary PCI for STEMI, unplanned repeat CAG during index hospitalization was infrequent and more commonly observed in patients with left anterior descending culprit in the presence of significant left ventricular dysfunction or shock and was associated with higher in-hospital recurrent myocardial infarction and major bleeding complications.

Assessment Framework for Recognizing Clinical Deterioration in Patients With ACS Undergoing PCI

TOPIC

Patients with acute coronary syndrome undergoing primary percutaneous coronary intervention are at risk of clinical deterioration that results in similar general signs and symptoms regardless of its cause. However, specific causes and forms of clinical deterioration are associated with key differences in assessment findings. Focused clinical assessments using a modified primary survey enable nurses to rapidly identify the cause and form of clinical deterioration, facilitating targeted treatment.

CLINICAL RELEVANCE

Clinical deterioration during percutaneous coronary intervention is associated with increased mortality and morbidity. Previous studies identified nursing inconsistencies when recognizing clinical deterioration, with inconsistent collection of cues and prioritization of cues related to cardiac performance over more sensitive indicators of clinical deterioration.

PURPOSE OF PAPER

To describe a framework to help nurses optimize physiological cue collection to improve recognition of clinical deterioration during periprocedural care of patients undergoing percutaneous coronary intervention for unstable acute coronary syndrome.

CONTENT COVERED

Literature analysis revealed 7 forms of clinical deterioration in patients undergoing percutaneous coronary intervention: coronary artery occlusion, stroke, ventricular rupture, valvular insufficiency, lethal cardiac arrhythmias, access-site and non-access-site bleeding, and anaphylaxis. Evidence for the pathophysiology, incidence, severity, and clinical features of each form of clinical deterioration is identified. A framework is proposed to help nurses conduct highly focused patient assessments, enabling prompt recognition of and response to the specific forms of clinical deterioration that occur in patients undergoing percutaneous coronary intervention.

Double or Triple Antithrombotic Treatment in Atrial Fibrillation Patients with Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) have traditionally received triple antithrombotic therapy (TAT) consisting of aspirin and a P2Y₁₂ inhibitor plus an oral anticoagulant (OAC) to reduce atherothrombotic events, even though this strategy is associated with a high risk of severe bleeding. Recent trials have indicated that dual antithrombotic therapy (DAT), consisting of a P2Y₁₂ inhibitor plus an OAC, may be superior to TAT in terms of bleeding risk; however, the trade-off regarding ischemic complications may be questionable. Patients who have had a myocardial infarction (MI) before undergoing PCI warrant special consideration because of the accompanying high ischemic risk, including stent thrombosis, which might be exacerbated by an aspirin-free strategy such as DAT. In particular, in the acute phase of ST-segment elevation MI (STEMI), the highly prothrombotic milieu may necessitate initial TAT, though durations may vary, making a tailored antithrombotic regimen for this high-risk subset of patients a fairly challenging and difficult scenario for clinicians. Since patients with MI, especially STEMI, are underrepresented in randomized trials, data regarding the optimal antithrombotic treatment in such patients are sparse. This review aims to analyze the outcomes of different antithrombotic regimens in patients with MI and AF undergoing PCI, define the role of DAT versus TAT regarding safety and efficacy outcomes, and address controversial issues and future perspectives.

Stent thrombosis in acute coronary syndromes: Patient-related factors and operator-related factors

OBJECTIVE

Stent thrombosis (ST) is a common phenomenon in acute coronary syndromes (ACS) when compared to stable coronary artery disease. This study analyzed the patient- and operator-related risk factors of ST in ACS.

METHODS

Coronary angiograms of 1738 consecutive ACS patients admitted in a large tertiary center between year 2014 and 2016 were analyzed retrospectively for the presence of ST. The paired angiograms [ST in ACS during and after percutaneous coronary intervention (PCI)] of the patients were analyzed by two independent observers, with focus on lesion characteristics and procedure techniques. Clinical and laboratory data were collected.

RESULTS

Stent thrombosis was found in 29 (1.6%) ACS patients, with a combination of at least one clinical/laboratory risk factor and one lesion/operator risk factor identified in 28 (96%) out of the 29 ACS patients with ST. The following risk factors for ST were found: Renal insufficiency (OR=4.14, p<0.001, 95% CI=1.73-9.88), type 2 diabetes (OR=2.21, p=0.034, 95% CI=1.06-4.61), excessive alcohol consumption (OR=3.12, p=0.023, 95% CI=1.17-8.33), stent implantation for ST-elevation myocardial infarction (STEMI) (OR=2.28, p=0.029, 95% CI=1.08-4.81), left main (LM) or left anterior descending artery (LAD) as culprit lesion (OR=2.80, p=0.010, CI 95%=1.27-5.95), and absence of antiplatelet therapy prior to ST (OR=3.58, p=0.002, 95% CI=1.60-7.96). The following lesion/operator possible risk factors were identified: Bifurcation lesion (n=7; 24%), heavy coronary calcifications (n=13; 44%), in-stent restenosis with secondary plate rupture (n=6, 20%), inappropriate stent size selection (n=6, 20%), and errors in periprocedural drug administration (n=4, 14%).

CONCLUSION

ST occurred in 1/62 ACS patients after PCI. A combination of clinical/laboratory and lesion/operator risk factors were present in almost all ACS patients with ST. This finding may support the search for strictly individualized strategies for the treatment of ACS patients with ST after PCI.

Value of CHA2DS2-VASc Score for Prediction and Ruling Out of Acute Stent Thrombosis After Primary Percutaneous Coronary Intervention

Acute stent thrombosis is an important complication of stent implantation. The CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, previous stroke, vascular disease, age between 65 and 74 years, female gender) score incorporates important cardiovascular (CV) risk factors and predicts prognosis in various CV conditions. We evaluated the value of the CHA2DS2-VASc score in predicting acute stent thrombosis (ie, thrombosis during 24 hours after stent placement) in patients undergoing primary percutaneous intervention for ST-segment elevated myocardial infarction. Patients with intraprocedural stent thrombosis and complications were excluded; 48 (2.1%) of 2732 patients had acute stent thrombosis according to our definition. Median CHA2DS2-VASc score was significantly higher in this stent thrombosis group. Cumulative acute stent thrombosis rates were 0.51% for CHA2DS2-VASc score ≤1, 1.55% for ≤2, 1.80% for ≤3, 2.00% for ≤4, 2.17% for ≤5, and 2.19% for ≤6. The CHA2DS2-VASc score (odds ratio = 1.390, 95% confidence interval = 1.118-1.728; P = .003) was an independent predictor of acute stent thrombosis. The CHA2DS2-VASc score ≤1 predicted the absence of the acute stent thrombosis with 91% specificity and 36% sensitivity. Further studies are needed to establish the value of this finding in the context of current clinical practice.

A modified predilation, sizing, and postdilation scoring system for patients undergoing metallic drug-eluting stent implantations

OBJECTIVE

This study sought to assess whether the predilation, scaffold/stent sizing, and postdilation (PSP) score for bioresorbable scaffold (BRS) implantation was associated with outcomes following metallic drug-eluting stent (DES) implantation.

BACKGROUND

The PSP score is associated with patients' prognoses after BRS implantation.

METHODS

This study involved 2,348 patients who underwent biodegradable polymer DES implantations during the PANDA III trial. The optimal PSP technique was defined according to previous studies of BRS implantations. The main outcome was target lesion failure (TLF) that comprised cardiac death, target-vessel myocardial infarction, or ischemia-driven target lesion revascularization.

RESULTS

Twenty-five (1.1%) patients fulfilled all the PSP criteria. The BRS-derived PSP score was of limited prognostic value for 2-year TLF after metallic DES implantation; optimal sizing was a protective factor, but optimal predilation was a risk factor. We built a new PSP model for DESs by identifying the following risk factors: predilation performed with a residual stenosis ≥70% or a balloon-to-quantitative coronary angiography (QCA)-determined reference vessel diameter (RVD) ratio >1:1, sizing performed with an RVD <2.25 mm or a stent diameter >0.25 mm wider than the QCA-RVD, a postprocedural stenosis diameter ≥30%, age, and the baseline SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery (SYNTAX) score. The new PSP scoring system predicted 2-year TLF (area under the curve, 0.69; 95% confidence interval, 0.65-0.73); a cutoff value of 19.2 points identified high-risk patients.

CONCLUSIONS

The new PSP scoring system, based on redefined PSP criteria, age, and the SYNTAX score, could help optimize metallic DES implantations.

Acute and sub-acute stent thrombosis: Frequency, predictors and features in patients undergoing primary percutaneous intervention at a tertiary care cardiac centre

•

Early stent thrombosis (ST) is relatively frequent in patients undergoing primary PCI.

•

Diabetic and hypertensive patients are at an increased risk of ST.

•

Presentation of patients in Killip Class III-IV is an independent predictor of early ST.

Objectives

To assess the frequency of early (acute and sub-acute) stent thrombosis (ST) after primary percutaneous coronary intervention (pPCI) and to identify its potential predictors.

Background

ST is a serious clinical event associated with a high mortality rate. A very limited data are available regarding the incidence rate of early ST after pPCI and its predictors, especially for Pakistani population.

Methods

Study included consecutive patients who underwent primary PCI. Telephonic follow-ups were made to obtain 30-days outcomes including ST, mortality, and re-occurrence of symptoms. ST was defined as per the standardized definition proposed by the Academic Research Consortium and classified as acute (during the procedure) and sub-acute (within 30 days).

Results

A total of 569 patients were included with 80.5% (485) male patients. The stent thrombosis (acute or sub-acute) was observed in 33 (5.8%) patients out of which 3 (9.1%) were definite ST while remaining 30 (90.9%) were probable ST. Patients who develop ST were predominantly male, hypertensive, diabetic, with reduced pre PCI LVEF (%) and Killip Class. A significantly higher in-hospital mortality rate was observed in patients with ST as compared to without ST, 36.4% (12/33) vs. 0.2% (1/536); p-value < 0.001 respectively. Killip Class (III-IV) was found to be the independent predictor of ST with an adjusted odds ratio of 5.2 [1.76–15.32].

Conclusions

Early stent thrombosis (ST) is relatively frequent in patients undergoing primary PCI. Diabetic and hypertensive patients are at an increased risk of ST and presentation of patients in Killip Class III-IV is an independent predictor of early ST.

P2Y12 inhibitors for the treatment of acute coronary syndrome patients undergoing percutaneous coronary intervention: current understanding and outcomes

Introduction: Inhibition of P2Y₁₂ platelet receptors consists a crucial target of pharmacologic treatment in acute coronary syndrome patients. Several controversial issues however still remain and these are analyzed.Areas covered: The significance of early and strong platelet inhibition in the early phase of STEMI and the role of pretreatment are discussed. Concerns regarding morphine administration are raised. The role of crushing integral tablets to expedite the onset of action of oral P2Y₁₂ inhibitors is emphasized. New data on the intravenous cangrelor are reported. Antiplatelet therapies as adjunct to thrombolysis, as well as the role of de-escalation antiplatelet therapy are analyzed.Expert opinion: Pharmacodynamic studies convincingly demonstrate a gap in the onset of antiplatelet action in STEMI cases, even when prasugrel or ticagrelor loading dose is used. The clinical benefit, however, of the early platelet inhibition and pretreatment is not entirely clear. Morphine delays the onset of action of oral agents, while this is expedited by crushing the integral tablets. Cangrelor devoids of these deficiencies by achieving fast and strong platelet inhibition in all clinical scenarios. Concomitant administration of novel antiplatelet agents with thrombolysis and de-escalation of antiplatelet treatment necessitate further study to reach definite conclusion.

Consensus Report on Patient Blood Management in Cardiac Surgery by Turkish Society of Cardiovascular Surgery (TSCVS), Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care (SCTAIC)

Anemia, transfusion and bleeding independently increase the risk of complications and mortality in cardiac surgery. The main goals of patient blood management are to treat anemia, prevent bleeding, and optimize the use of blood products during the perioperative period. The benefit of this program has been confirmed in many studies and its utilization is strongly recommended by professional organizations. This consensus report has been prepared by the authors who are the task members appointed by the Turkish Society of Cardiovascular Surgery, Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care to raise the awareness of patient blood management. This report aims to summarize recommendations for all perioperative blood- conserving strategies in cardiac surgery.

High-Flow Extracranial-to-Intracranial Bypass for Treatment of Thrombotic Parent Vessel Occlusion After Stent-Assisted Aneurysm Coiling as a Potential Rescue Therapy

INTRODUCTION

Stent thrombosis (ST) is a known complication after intracranial stent implantation. The pathophysiology of ST is multifactorial, and standardized treatments for ST remain uncertain.

CASE DESCRIPTION

A patient harboring an unruptured aneurysm of the posterior communicating segment of the left internal carotid artery was treated with stent-assisted coil embolization while on dual antiaggregation therapy. Despite adherence to medication, ST occurred 8 days after the intervention. Following tirofiban infusion, the thrombus dissolved and clinical symptoms improved. However, after tirofiban was stopped, the patient experienced again ischemic symptoms. The patient underwent high-flow extracranial-to-intracranial bypass with good patency of the graft and resolution of symptoms.

CONCLUSIONS

In case of refractory ST, high-flow extracranial-to-intracranial bypass proved to be in this case a feasible and effective rescue option.

At least seven days delayed stenting using minimalist immediate mechanical intervention (MIMI) in ST-segment elevation myocardial infarction: the SUPER-MIMI study

AIMS

The aim of this study was to ascertain whether a minimalist immediate mechanical intervention (MIMI) aiming to restore an optimal Thrombolysis In Myocardial Infarction (TIMI) flow in the culprit artery, followed ≥7 days later by a second percutaneous coronary intervention with intentional stenting, is safe in patients with ST-segment elevation myocardial infarction and large thrombotic burden.

METHODS AND RESULTS

SUPER-MIMI was a prospective, observational trial conducted between January 2014 and April 2015 in 14 French centres. A total of 155 patients were enrolled. The pharmacological therapy was left to the operator's discretion. Eighty-one patients (52.3%) had glycoprotein IIb/IIIa inhibitors (GPI) initiated before the end of the first procedure. The median (interquartile range [IQR]) delay between the two procedures was eight (seven to 12) days. Infarct-related artery reocclusion between the two procedures (primary endpoint) occurred in two patients (1.3%), neither of whom received GPI treatment. TIMI flow was maintained or improved between the end of the first procedure and the beginning of the second procedure in all patients. Thrombotic burden and stenosis severity diminished significantly between the two procedures. Stents were ultimately implanted in 97 patients (62.6%).

CONCLUSIONS

Deferred stenting (≥7 days) in patients with a high thrombus burden was safe on a background of GPI therapy.

Quantification of thrombus formation in malapposed coronary stents deployed in vitro through imaging analysis

Stent thrombosis is a major complication of coronary stent and scaffold intervention. While often unanticipated and lethal, its incidence is low making mechanistic examination difficult through clinical investigation alone. Thus, throughout the technological advancement of these devices, experimental models have been indispensable in furthering our understanding of device safety and efficacy. As we refine model systems to gain deeper insight into adverse events, it is equally important that we continue to refine our measurement methods. We used digital signal processing in an established flow loop model to investigate local flow effects due to geometric stent features and ultimately its relationship to thrombus formation. A new metric of clot distribution on each microCT slice termed normalized clot ratio was defined to quantify this distribution. Three under expanded coronary bare-metal stents were run in a flow loop model to induce clotting. Samples were then scanned in a MicroCT machine and digital signal processing methods applied to analyze geometric stent conformation and spatial clot formation. Results indicated that geometric stent features play a significant role in clotting patterns, specifically at a frequency of 0.6225 Hz corresponding to a geometric distance of 1.606 mm. The magnitude-squared coherence between geometric features and clot distribution was greater than 0.4 in all samples. In stents with poor wall apposition, ranging from 0.27 mm to 0.64 mm maximum malapposition (model of real-world heterogeneity), clots were found to have formed in between stent struts rather than directly adjacent to struts. This early work shows how the combination of tools in the areas of image processing and signal analysis can advance the resolution at which we are able to define thrombotic mechanisms in in vitro models, and ultimately, gain further insight into clinical performance.

Cangrelor in Percutaneous Coronary Intervention: Current Status and Perspectives

Cangrelor is an intravenously administered P2Y₁₂ receptor antagonist with very fast, potent, and quickly reversible action. In the CHAMPION PHOENIX trial, cangrelor provided an improved anti-ischemic protection compared with clopidogrel, without increasing the risk of severe bleeding. Cangrelor is currently approved by drug regulating authorities for patients undergoing percutaneous coronary intervention (PCI) without prior treatment with a P2Y₁₂ receptor antagonist and not receiving a glycoprotein IIb/IIIa inhibitor, while its use is endorsed with a class IIb recommendation by the European Society of Cardiology guidelines. Several subanalyses of CHAMPION PHOENIX trial have tried to elucidate the role of cangrelor in PCI, including its usefulness during a 2-hour landmark analysis, impact on intraprocedural stent thrombosis, and reduction in myocardial infarction (MI) rate. The influence of gender, geographic region, access site, and bivalirudin use on cangrelor's effects has also been reported. In patients with ST elevation MI and in clinical scenarios of disturbed absorption of oral antiplatelet agents or in need of an intravenous agent, cangrelor may surpass oral agents' drawbacks. Transitioning to an oral agent is mandatory following cangrelor infusion discontinuation, although ticagrelor may be administered earlier without any pharmacodynamic interaction. Nevertheless, the clinical role of cangrelor in conjunction with administration of prasugrel or ticagrelor remains unclear. Accruing real-life experience is expected to improve our understanding of cangrelor's role in everyday clinical practice.

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

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

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.

Thrombotic responses to coronary stents, bioresorbable scaffolds and the Kounis hypersensitivity-associated acute thrombotic syndrome

Percutaneous transluminal coronary angioplasty with coronary stent implantation is a life-saving medical procedure that has become, nowadays, the most frequent performed therapeutic procedure in medicine. Plain balloon angioplasty, bare metal stents, first and second generation drug-eluting stents, bioresorbable and bioabsorbable scaffolds have offered diachronically a great advance against coronary artery disease and have enriched our medical armamentarium. Stented areas constitute vulnerable sites for endothelial damage, endothelial dysfunction, flow turbulence, hemorheologic changes, platelet dysfunction, coagulation changes and fibrinolytic disturbances. Implant surface attracts several proteins such as albumin, fibronectin, fibrinogen, and complement that lead to complement system activation. Macrophages recognize the implant as foreign substance due to protein adsorption and its continuous presence results in macrophage differentiation and fusion into foreign body giant cells. Polymer coating, stent metallic platforms and the released drugs can act as strong antigenic complex that apply continuous, repetitive, persistent and chronic hypersensitivity irritation to the coronary intima. The concomitant administration of oral antiplatelet drugs and environmental exposures can induce hypersensitivity inflammation. A class of platelets, activated via high-affinity and low-affinity IgE hypersensitivity receptors FCγRI, FCγRII, FCεRI and FCεRII, can induce Kounis hypersensitivity-associated thrombotic syndrome inside the stented coronaries. Type III variant of this syndrome is diagnosed when coronary artery stent thrombosis is associated with thrombus infiltrated by eosinophils or mast cells and/or when coronary intima, media and adventitia adjacent to stent, is infiltrated by eosinophils or mast cells. Careful history of hypersensitivity reactions to all implanted materials and concomitant drugs with monitoring of inflammatory mediators as well as lymphocyte transformation studies to detect hypersensitivity must be undertaken in order to avoid disastrous consequences. Food and Drug Administration recommendations for coronary stent implantation should be applied also to bioresorbable scaffolds. Further studies with inert and non-allergenic implants are necessary.

Thrombolysis-facilitated primary percutaneous coronary intervention as a therapeutic approach to stent thrombosis

BACKGROUND

Stent thrombosis is a clinically significant event occurring days to weeks or, infrequently, months or years after percutaneous coronary intervention (PCI). Current therapeutic approach is immediate PCI aimed to recanalize the occluded artery in order to restore flow and diminish irreversible myocardial damage.

METHODS

We evaluated the coronary patency, TIMI flow and TIMI myocardial perfusion grade (TMPG) in 6 patients presenting with STEMI due to stent thrombosis treated by thrombolysis followed by immediate PCI. These were compared with control patients treated conventionally by primary PCI.

RESULTS

Immediate or early coronary angiography in the treatment group showed good coronary flow in 5 of 6 implicated arteries, whereas immediate angiography in the control group demonstrated 8 completely occluded coronary arteries of 9 with stent thrombosis. The pre-intervention TIMI flow in the control study group was 0.2±0.5 (median-0), and TMPG was 0.1±0.3 (median-0) compared with 2.1±1.1 (median-2.3, p<0.001) and 1.8±1.0 (median-2, p<0.001) in the treatment group, respectively. This striking difference in the rate of coronary patency, pre-procedural TIMI flow and TMPG, however, did not translate into better cardiac function in the treatment group.

CONCLUSIONS

These findings suggest that thrombolysis-facilitated PCI may confer benefit and need not be considered contraindicated when treating stent thrombosis. This therapeutic approach should be evaluated as a viable therapeutic approach to stent thrombosis.

Two Consecutive Episodes of Acute Myocardial Infarction Occurring in Different Coronary Arteries of a Single Patient with Sepsis

Although recurrent ST-segment elevation myocardial infarction (STEMI) in the same coronary artery due to acute stent thrombosis has been reported in the literature, there have been no reported cases discussing consecutive STEMI recurring in different coronary arteries in the same patient in one day. Herein, we report an elderly male patient initially suffering from STEMI over the inferior wall who subsequently had another episode of STEMI over the anterior wall within several hours. Despite primary percutaneous coronary intervention being performed over both the right coronary artery and the left anterior descending artery, the patient eventually expired notwithstanding intensive care. This case should caution physicians that consecutive STEMI in different coronary arteries is an extremely rare but still possible medical phenomenon, and could lead to catastrophic clinical outcome.

KEY WORDS

Myocardial infarction; Primary percutaneous coronary intervention; Recurrent ST-elevation.

Individualising dual antiplatelet therapy after percutaneous coronary intervention: the IDEAL-PCI registry

OBJECTIVE

To evaluate the clinical utility of individualising dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) in an all-comers population, including ST-elevation myocardial infarction (STEMI) patients.

SETTING

Tertiary care single centre registry.

PARTICIPANTS

1008 consecutive PCI patients with stent implantation, without exclusion criteria.

INTERVENTION

Peri-interventional individualisation of DAPT, guided by multiple electrode aggregometry (MEA), to overcome high on-treatment platelet reactivity (HPR) to ADP-induced (≥50 U) and arachidonic acid (AA)-induced aggregation (>35 U).

OUTCOME MEASURES

The primary efficacy end point was definite stent thrombosis (ST) at 30 days. The primary safety end point was thrombolysis in myocardial infarction (TIMI) major and minor bleeding. Secondary end points were probable ST, myocardial infarction, cardiovascular death and the combined end point: major cardiac adverse event (MACE).

RESULTS

53% of patients presented with acute coronary syndrome (9% STEMI, 44% non-ST-elevation). HPR to ADP after 600 mg clopidogrel loading occurred in 30% of patients (73±19 U vs 28±11 U; p<0.001) and was treated by prasugrel or ticagrelor (73%), or clopidogrel (27%) reloading (22±12 U; p<0.001). HPR to ADP after prasugrel loading occurred in 2% of patients (82±26 U vs 19±10 U; p<0.001) and was treated with ticagrelor (34±15 U; p=0.02). HPR to AA occurred in 9% of patients with a significant higher proportion in patients with HPR to ADP (22% vs 4%, p<0.001) and was treated with aspirin reloading. Definite ST occurred in 0.09% of patients (n=1); probable ST, myocardial infarction, cardiovascular death and MACE occurred in 0.19% (n=2), 0.09% (n=1) and 1.8% (n=18) of patients. TIMI major and minor bleeding did not differ between patients without HPR and individualised patients (2.6% for both).

CONCLUSIONS

Individualisation of DAPT with MEA minimises early thrombotic events in an all-comers PCI population to an unreported degree without increasing bleeding. A randomised multicentre trial utilising MEA seems warranted.

TRIAL REGISTRATION NUMBER

http://www.clinicaltrials.gov; NCT01515345.

White blood cell, hemoglobin and platelet distribution width as short-term prognostic markers in patients with acute myocardial infarction

The aim of this study was to assess the prognostic value of combined use of white blood cell (WBC), hemoglobin (Hb), and platelet distribution width (PDW) in patients with acute myocardial infarction (AMI). This study included 1,332 consecutive patients with AMI. Patients were categorized into complete blood cell (CBC) group 0 (n=346, 26.0%), 1 (n=622, 46.7%), 2 (n=324, 24.3%), and 3 (n=40, 3.0%) according to the sum of the value defined by the cut-off levels of WBC (1, ≥ 14.5 × 10(3)/µL; 0, <14.5 × 10(3)/µL), Hb (1, <12.7 g/dL; 0, ≥ 12.7 g/dL), and PDW (1, ≥ 51.2%; 0: <51.2%). In-hospital death occurred in 59 (4.4%) patients. Patients who died during index hospitalization had higher WBC and PDW and lower Hb. The patients could be stratified for in-hospital mortality according to CBC group; 1.2%, 2.7%, 9.0%, and 22.5% in CBC groups 0, 1, 2, and 3 (P<0.001), respectively. In multivariate logistic regression analysis, CBC group ≥ 2 (odds ratio, 3.604; 95% confidence interval, 1.040-14.484, P=0.043) was an independent predictor for in-hospital death. The prognostic impact of the combined use of CBC markers remained significant over 12 months. In conclusions, combination of WBC, Hb, and PDW, a cheap and simple hematologic marker, is useful in early risk stratification of patients with AMI.

Short-term consequences of angiographically-confirmed coronary stent thrombosis

OBJECTIVES

To conduct a meta-analysis to quantify the real-world incidence of in-hospital or 30-day death or myocardial infarction (MI), and angiographically-confirmed ST-related treatment costs.

BACKGROUND

The short-term clinical and economic consequences of coronary stent thrombosis (ST) are thought to be significant.

METHODS

We searched MEDLINE, Embase and Scopus from January 2000-July 2012 to identify observational/registry studies that evaluated a cohort of ≥ 25 patients experiencing angiographically-confirmed thrombosis of a drug-eluting or bare-metal stent, required the use of dual-antiplatelet therapy for guideline-recommended durations, and reported incidences of in-hospital or 30-day death or MI and/or ST-related treatment costs. Incidences and costs from each study were pooled using random-effects meta-analysis.

RESULTS

Twenty-three studies were included. Of the 13 studies reporting in-hospital outcomes, 12 (N=8,832 STs) reported mortality data, with the pooled incidence rate estimated to be 7.9%, 95%CI=5.4%-11.3%, I(2)=86%. Ten studies (N=1,294 STs) reported 30-day death, with a pooled incidence of 11.6%, 95%CI=8.8%-15.1%, I(2)=55%. Patients experiencing early ST (within 30-days of implant) had higher in-hospital and 30-day mortality than those experiencing very-late ST (interaction p<0.04 for both). Stent type had no significant effect on in-hospital or 30-day mortality. In the 5 studies (N=542 STs) and 3 studies (N=180 STs) reporting in-hospital and 30-day MI, respectively, the pooled incidence rates were 6.1%, 95%CI=2.1%-16.2%, I(2)=88% and 9.5%, 95%CI=3.8%-22.0%, I(2)=65%. One study reported costs associated with ST, estimating the median/patient cost of hospitalization to treat early ST at $11,134 (in 2000US$).

CONCLUSIONS

Regardless of stent type used, the short-term consequences of coronary ST appear significant.

Clopidogrel pretreatment in primary percutaneous coronary intervention: prevalence of high on-treatment platelet reactivity and impact on preprocedural patency of the infarct-related artery

To date, there is limited data on levels of platelet inhibition achieved in patients with ST-elevation myocardial infarction (STEMI) who are loaded with clopidogrel and aspirin (ASA) prior to undergoing primary percutaneous coronary intervention (P-PCI). The aim of this investigation was to evaluate the percentage of STEMI patients with high on-treatment platelet reactivity (HPR) to clopidogrel at the time of initiating P-PCI and its association with the initial patency of the infarct-related artery (IRA). This prospective pharmacodynamic study included 50 STEMI patients, previously naïve to oral antiplatelet agents, who received 500-mg ASA and 600-mg clopidogrel loading doses prior to P-PCI. Platelet function assessment was performed at the beginning of the procedure using various assays, including VerifyNow™ system (primary endpoint), light transmission aggregometry and multiple electrode aggregometry. The percentage of patients with suboptimal response to clopidogrel and ASA assessed with the VerifyNow™ system was 88.0% and 28.6%, respectively. Similar results were obtained with the other assays used. A higher percentage of patients with initial patency of the IRA was observed among those patients without HPR compared with those with HPR to clopidogrel (66.7% vs 15.9%; p=0.013), while no differences were observed regarding postprocedural angiographic or electrocardiographic outcomes. In conclusion, this study shows that a high percentage of STEMI patients have inadequate levels of clopidogrel-induced and, to a lesser extent, aspirin-mediated platelet inhibition when starting a P-PCI procedure, and suggests that a poor response to clopidogrel might be associated with impaired initial TIMI flow in the IRA.

Prehospital treatment of ST-segment elevated myocardial infarction patients

Providing optimal care to patients with ST-segment elevated myocardial infarction is challenging. If a patient experiences chest pain and calls the emergency number, a cascade of actions is initiated that should lead to a diagnosis, start of treatment and reperfusion of the infarcted myocardium. This should all happen within 90 min after first medical contact, irrespective of the location of the patient or the time of day. The complex organization that is needed to achieve this goal in every ST-segment elevated myocardial infarction patient accounts for a fascinating interplay between prehospital and in-hospital care, in a situation when every minute counts. State-of-the-art care should be provided according to the latest insights and guidelines.

Simultaneous Thrombosis of Two Drug-Eluting Stents After Discontinuation of Dual Antiplatelet Therapy for a Day

Stent thrombosis is rare but can lead to potential severe consequence. The incidence is relative higher in drug-eluting sent than bare-metal stent implantation. Dual antiplatelet therapy is the major treatment to avoid early and late stent thrombosis. Simultaneous two stents thrombosis is rare. Although mechanical or/and procedure factors may predispose to stent thrombosis occurred, simultaneous two stents thrombosis implies possibly ineffective antiplatelet therapy. We report a case with simultaneous two stent thrombosis and complicated with cardiogenic shock after lost antiplatelet therapy for one day. We try to emphasize to properly educate patients about the importance of continuous drug use to avoid catastrophic tragedy.

Virtual histology-intravascular ultrasound assessment of lesion coverage after angiographically-guided stent implantation in patients with ST Elevation myocardial infarction undergoing primary percutaneous coronary intervention

An occlusion or severe stenosis (angiographic culprit lesion) of the infarct-related artery is frequently located at the site of the maximum thrombus burden, whereas the origin of the plaque rupture (the true culprit) can be situated proximal or distal to it. The aim of this study was to examine stent coverage of true culprit lesions in 20 patients who underwent primary percutaneous coronary intervention and had Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow restored in the infarct-related artery by angiographically guided direct stenting. Images of lesions were obtained using virtual histology-intravascular ultrasound before and after intervention (blinded to the operator). Plaque rupture sites were identified by intravascular ultrasound in 12 lesions (60%), 11 proximal and 1 distal to the minimum luminal area (MLA). Maximum necrotic core sites were found proximal to the MLA in 16 lesions, at the MLA in 3 lesions, and distal to the MLA in 1 lesion. Plaque rupture sites were fully covered by stents in 11 lesions. Virtual histology-intravascular ultrasound-derived thin-cap fibroatheroma longitudinal geographic misses were found in 10 lesions, 7 in the proximal reference segment and in 3 patients in the proximal and distal reference segments. In conclusion, in about 50% of patients who undergo primary percutaneous coronary intervention for ST-segment elevation myocardial infarction with optimal angiographic results, the stent does not fully cover the maximum necrotic core site related to the culprit lesion.

Efficacy and safety of unfractionated heparin plus glycoprotein IIb/IIIa inhibitors during revascularization for an acute coronary syndrome: a meta-analysis of randomized trials performed with stents and thienopyridines

BACKGROUND

Early studies of glycoprotein IIb/IIIa inhibitors (GPIs) demonstrated benefit during percutaneous coronary intervention for acute coronary syndromes (ACS). Since their introduction, the magnitude of benefit of GPIs has become unclear.

HYPOTHESIS

We hypothesized that adding a GPI to unfractionated heparin in ACS patients treated with stents and thienopyridines is beneficial.

METHODS

We searched the MEDLINE, Cochrane, and clinicaltrials.gov databases for randomized clinical trials that studied the use of GPIs during ACS. We required that patients be randomly assigned to unfractionated heparin plus a GPI versus unfractionated heparin plus placebo (or control). Additional inclusion criteria included the use of coronary stents and periprocedural thienopyridines. Outcomes were assessed at 30 days. Random effects DerSimonian-Laird summary risk ratios (RR) and 95% confidence intervals (CIs) were constructed.

RESULTS

Sixteen studies with 7611 patients were included. Myocardial infarction was 3.1% with GPI versus 4.4% with control (RR = 0.74; 95% CI, 0.59-0.94, P = 0.014); revascularization, 1.7% versus 2.7% (RR = 0.64; 95% CI, 0.46-0.89, P = 0.008); major bleeding, 2.5% versus 2.1% (RR = 1.21; 95% CI, 0.89-1.63, P = 0.22); minor bleeding, 5.5% versus 4.1% (RR = 1.37; 95% CI, 1.06-1.78, P = 0.016); and mortality, 2.2% versus 2.9% (RR = 0.79; 95% CI, 0.59-1.06, P = 0.12), respectively.

CONCLUSIONS

Among ACS patients treated with stents and thienopyridines, GPIs were associated with reduced myocardial infarction and revascularization. Minor, but not major bleeding was increased with GPIs. Mortality was similar between the groups. © 2011 Wiley Periodicals, Inc. Supporting information may be found in the online version of this article This work was supported by an unrestricted grant from the Florida Heart Research Institute, which had no role in the study design, data collection, analysis, or interpretation, manuscript writing, or decision to proceed with publication. Anthony A Bavry has received research support from Novartis Pharmaceuticals and serves as a contractor for American College of Cardiology Cardiosource. The other authors have no funding, financial relationships, or conflicts of interest to disclose.

The relationship between platelet reactivity and infarct-related artery patency in patients presenting with a ST-elevation myocardial infarction

Both heightened platelet reactivity and an occluded infarct related artery (IRA) on initial angiography and at the time of primary percutaneous coronary intervention (PCI) are associated with a worsened clinical outcome in patients with ST-elevation myocardial infarction (STEMI). However, the relationship between platelet reactivity and IRA patency has not yet been established. Consecutive STEMI-patients were enrolled in this study. Patients who had TIMI-flow (thrombolysis in myocardial infarction) 0 or 1 on initial angiography constituted the occluded IRA group and patients having TIMI-flow 2 or 3 comprised the IRA patent group. Platelet function measurements were performed using the PFA-100 COL/ADP cartridge and light transmittance aggregometry without agonist (spontaneous) and after stimulation with adenosine diphosphate (ADP) and arachidonic acid (AA). Ninety-nine patients were enrolled, of whom 49 presented with an occluded IRA. Multivariate analysis identified the following independent factors to be associated with an occluded IRA; short COL/ADP closure time (ORper quartile increase=0.60; 95% CI, 0.39-.93; p=0.02), the 20 μM ADP-induced light transmittance aggregometry (ORper quartile increase =1.77; 95% CI, 1.15-2.73; p=0.01) and leukocyte counts (odds ratio [OR]=1.21; 95% CI, 1.05-1.39; p = 0.008). In conclusion, heightened platelet reactivity and elevated leukocyte counts are associated with an occluded IRA upon presentation in STEMI-patients. These results emphasise the importance of potent antithrombotic therapy early after the onset of symptoms, to obtain early recanalisation of the IRA.

Eosinophilic responses to stent implantation and the risk of Kounis hypersensitivity associated coronary syndrome

The use of drug eluting stents constitutes a major breakthrough in current interventional cardiology because it is more than halves the need of repeat interventions. It is incontrovertible that coronary stents, in general, have been beneficial for the vast majority of patients. A small increase in thrombosis, following DES implantation, is offset by a diminished risk of complications associated with repeat vascularization. However, late and, especially, very late stent thrombosis is a much feared complication because it is associated with myocardial infarction with increased mortality. Despite that stent thrombosis is thought to be multifactorial, so far clinical reports and reported pathology findings in patients died from coronary stent thrombosis as well as animal studies and experiments, point toward a hypersensitivity inflammation. The stented and thrombotic areas are infiltrated by interacting, via bidirectional stimuli inflammatory cells including eosinophils, macrophages, T-cells and mast cells. Stented regions constitute an ideal surrounding for endothelial damage and dysfunction, together with hemorheologic changes and turbulence as well as platelet dysfunction, coagulation and fibrinolytic disturbances. Drug eluting stent components include the metal strut which contains nickel, chromium, manganese, titanium, molybdenum, the polymer coating and the impregnated drugs which for the first generation stents are: the antimicrotubule antineoplastic agent paclitaxel and the anti-inflammatory, immunosuppressive and antiproliferative agent sirolimus. The newer stents which are called cobalt-chromiun stents and elute the sirolimus analogs everolimus and zotarolimus both contain nickel and other metals. All these components constitute an antigenic complex inside the coronary arteries which apply chronic, continuous, repetitive and persistent inflammatory action capable to induced Kounis syndrome and stent thrombosis. Allergic inflammation goes through three phases, the early phase, the late phase and the chronic phase and these three phases correspond temporally with early (acute and sub acute), late and very late stent thrombosis. Bioabsorbable allergy free poly lactic acid self expanding stents, nickel free stainless steel materials, stent coverage with nitric oxide donors and antibodies with endothelial progenitor cell capturing abilities as well as stents eluting anti-inflammatory and anti-allergic agents might be the solution of this so feared and devastating stent complication.