Clinical, procedural, and pharmacologic correlates of acute and subacute stent thrombosis: results of a multicenter case-control study with 145 thrombosis events

Clinical characteristics, angiographic findings, and one-year outcome of 101 consecutive stent thrombosis cases in British Columbia

BACKGROUND

Stent thrombosis (ST) is rare, but is associated with significant morbidity and mortality.

METHODS

We analyzed data from the British Columbia (BC) Registry from April 2011-January 2012.

RESULTS

101 ST cases were reported and verified. Based on timing, ST was considered early (≤30days) in 35.6%, late (>30days-1year) in 17.8% and very late (>1year) in 46.5%. The majority (68.5%) presented with STEMI, and the remaining with non-STEMI (31.5%). Most vessels were functionally occluded (TIM1 flow grade ≤1 in 67.1%). Thrombus burden was high (TIMI thrombus grade ≥4 in 77.2%). Aspiration thrombectomy was performed in 41% of cases. New stents were implanted in 62.4% cases. Intra-coronary imaging was low (11%). At the original stent implantation, STEMI was the clinical presentation in 39.6%, the lesion was complex in 62.1%, and thrombus was visualized in 23.0%. Prognosis after ST was unfavorable with high mortality (11.9% at 30days and 16.8% at one year), and further revascularization (5.0% repeat PCI and 6.9% coronary artery bypass graft surgery). Early ST was associated with worse clinical outcome compared to late/very late ST: 30-day mortality at 22.2% versus 6.2% (p=0.02), and 1-year mortality at 27.8% versus 10.8% (p=0.05).

CONCLUSIONS

In this prospective registry from BC, all ST presented with myocardial infarction, and the majority was treated with emergency PCI. Additional stents were commonly implanted with infrequent use of intracoronary imaging. Mortality rate was higher for early ST in comparison with late/very late ST. A comprehensive approach should be developed to treat this difficult complication.

Incidence and prognosis of stent thrombosis following percutaneous coronary intervention in Middle Eastern patients: The First Jordanian Percutaneous Coronary Intervention Registry (JoPCR1)

BACKGROUND

The incidence, risk factors, and outcome of stent thrombosis (ST) after percutaneous coronary intervention (PCI) in Middle Eastern patients are largely unknown.

OBJECTIVE

To determine the incidence, risk factors and outcome in our population.

DESIGN

Retrospective study of a prospective multicenter registry of consecutive patients who underwent PCI between January 2013 and February 2014 (JoPCR1).

SETTING

12 tertiary care centers in Amman and Irbid, Jordan.

PATIENTS AND METHODS

We collected clinical baseline and follow-up data.

MAIN OUTCOME MEASURES

Incidence of stent thrombosis.

RESULTS

The mean (standard deviation) age of patients (n=2426) was 59.0 (10.1) years and 20.6% were women. Stents (n=3038) were drug eluting (89.6%), bare metal (9.4%) or bioabsorbable (1.0%). After 1 year, 47 patients (1.97%) had ST, including 44 (94%) definite and 3 (6%) probable ST. Patients who had ST presented with sudden death (n=6; 12.2%) or with a nonfatal event (n=43; 87.8%). Nonfatal events included non-ST-segment elevation acute coronary syndrome (26; 53%), acute ST segment elevation myocardial infarction (n=15; 31%) or heart failure (n=2; 4.1%). ST was associated with significantly higher one-month (22.0% vs. 0.7%) and one-year (12.3% vs. 0.73%) mortality rates compared with patients who did not have ST (P < .001). ST patients were younger (mean age 52.9 years vs. 58.4 years), had heart failure (64% vs. 18%), left ventricular ejection fraction (LVEF) < 45% (36% vs. 13%), ST-segment deviation (70% vs. 48%), and elevated cardiac biomarkers blood levels (62% vs. 40%). In the multivariate analysis, the only factor that was significantly associated with ST was the heart failure (OR=3.5, 95% confidence interval: 1.8, 6.6; P < .0001).

CONCLUSIONS

The incidence of ST was not different from that in other regions and was associated with an increased one-year mortality. Younger age, heart failure, low LVEF, ST-segment deviation, and elevated blood levels of cardiac biomarkers were predictors of ST.

LIMITATIONS

Possible selection bias, recall bias, and missing or incomplete information. The majority of patients were lost to follow up after the 6th month. The registry may not fully represent PCI practice and outcome in all areas in the country or region.

Utility of optical coherence tomography to assess a hazy intracoronary image after percutaneous coronary intervention

Although its use in daily practice is not common, optical coherence tomography (OCT) is a powerful research tool in invasive cardiology. This report describes a hazy angiography image after percutaneous coronary intervention that has been assessed using OCT. Based on the results of the OCT, the patient underwent an elective coronary angioplasty with standard anticoagulation. After implantation of the stent, an intracoronary hazy image was seen on angiography. The use of OCT permitted a correct diagnosis and a successful treatment. This paper provides a discussion of the advantages and disadvantages of OCT, and a comparison with intravascular ultrasound.

Current Concepts in the Clinical Utility of Platelet Reactivity Testing

The pharmacodynamic effect of clopidogrel varies among individuals; approximately a third will have high on-treatment platelet reactivity (HTPR) to adenosine diphosphate and may benefit from more intensive antiplatelet therapy. Platelet reactivity testing has an important role in monitoring the therapeutic efficiency of clopidogrel and the safety of more potent drugs that confer an increased bleeding risk, because it provides a direct measure of the biological effect of these drugs. Numerous studies have demonstrated an association between HTPR and the risk of cardiac events in acute coronary syndrome (ACS) or after percutaneous coronary intervention (PCI). While the prognostic value of platelet reactivity testing following PCI has been demonstrated repeatedly in cohort studies and meta-analyses, randomised controlled studies investigating the clinical utility of the technique to guide treatment decisions failed to improve clinical outcomes of clopidogrel-treated patients undergoing stent implantation. Available data suggest that platelet function monitoring may be carried out in clopidogrel-treated patients with a higher risk of thrombotic events. These include patient risk factors such as body mass index (BMI), type 2 diabetes, and those prior unexpected ischemic events such as stent thrombosis, as well as procedural risk factors. As we move towards conclusively defining a therapeutic window associated with both cardiovascular (upper threshold) and bleeding risk (lower threshold) for antiplatelet agents, platelet reactivity testing will become a central tool in the practice of personalised strategies.

[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.

Balancing hemorrhagic and thrombotic complications in a patient with a very late paclitaxel-eluting stent thrombosis: a clinical case report

Stent thrombosis is a rare but potentially fatal complication of percutaneous treatment of coronary disease. Its occurrence after placement of drug eluting stents (DES) has raised concerns, as this event may occur very late after stent implantation. Here, we report a case of very late stent thrombosis (VLST) experienced 1462 days after DES deployment in a patient with challenging clinical status, requiring counterbalancing hemorrhagic and thrombotic risk factors.

Oral antiplatelet therapy in diabetes mellitus and the role of prasugrel: an overview

Diabetics have a prothrombotic state that includes increased platelet reactivity. This contributes to the less favorable clinical outcomes observed in diabetics experiencing acute coronary syndromes as well as stable coronary artery disease. Many diabetics are relatively resistant to or have insufficient response to several antithrombotic agents. In the setting of percutaneous coronary intervention, hyporesponsiveness to clopidogrel is particularly common among diabetics. Several strategies have been examined to further enhance the benefits of oral antiplatelet therapy in diabetics. These include increasing the dose of clopidogrel, triple antiplatelet therapy with cilostazol, and new agents such as prasugrel. The large TRITON TIMI 38 randomized trial compared clopidogrel to prasugrel in the setting of percutaneous coronary intervention for acute coronary syndromes. The diabetic subgroup (n = 3146) experienced considerable incremental benefit with a 4.8% reduction in cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke at 15-month follow-up with prasugrel treatment. Among diabetics on insulin this combined endpoint was reduced by 7.9% at 15 months. Major bleeding was not increased in the diabetic subgroup. This confirms the general hypothesis that more potent oral antiplatelet therapy can partially overcome the prothrombotic milieu and safely improve important clinical outcomes in diabetics.

Triggering mechanisms of stent thrombosis

AIMS

The aim of this study was to determine the role of potential triggers of stent thrombosis.

METHODS AND RESULTS

Patients (n = 437) with "definite" ST were recruited consecutively in the setting of a large multicentre observational cohort study. Patients were interviewed with validated questionnaires to identify one of the following triggers: i) timing of onset of ST, ii) performance of vigorous ( ≥ 6 MET) physical activity in the two hours preceding ST, iii) presence of emotional stress (experiencing a serious life event in the 14 days preceding the ST or feelings of anger in the 12 hours of ST) and iv) presence of a documented active infection at the time of ST. A total of 363 patients (83.1%) were able to supply adequate information. A significant trigger was identified in 83 patients (22.9%). Analysis of the different categories according to timing of ST revealed a higher prevalence of triggers with an increasing time-interval between index PCI and ST. Analysis of circadian variation showed a steep peak incidence from 7 am-12 pm.

CONCLUSIONS

Triggering mechanisms such as time of the day, physical exertion, emotional stress and infection may play an important role in a considerable number of patients presenting with ST, in particular in patients with (very) late ST.

Subacute Drug-Eluting Stent Thrombosis Caused by Stent Underexpansion: Evaluation by Optical Coherence Tomography

We present the case report of a patient presenting with ST segment elevation myocardial infarction due to a subacute drug-eluting stent trombosis within the proximal segment of the left circumflex artery (LCX). Six days before a total chronic occlusion was treated at the mid segment of the LCX by overlapping two drug-eluting stents. Optical coherence tomography (OCT) was helpful to demonstrate stent underexpansion of the overlaping segment as the main mechanism of early stent thrombosis. This case is illustrative about the potential role of OCT to identify the mechanisms of ST and thus guiding the PCI procedure. Moreover, our case shows the capability of the Imagewire to cross a severe stenosis due to stent underexpansion that could not be crossed by the IVUS catheter.

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

BACKGROUND

Early coronary stent thrombosis occurs most frequent after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI).

OBJECTIVES

To identify the specific predictors of, respectively, acute and subacute stent thrombosis in patients after primary PCI for STEMI.

PATIENTS/METHODS

Consecutive STEMI patients with angiographically confirmed early stent thrombosis were enrolled and compared in a 2 : 1 ratio with a matched control group. Clinical outcome was collected up to 1 year.

RESULTS

Of 5842 STEMI patients treated with primary PCI, 201 (3.5%) presented with a definite early stent thrombosis. Of these, 97 (1.7%) had acute stent thromboses and 104 (1.8%) had subacute stent thromboses. Postprocedurally discovered dissection, undersizing and smaller stent diameter were the strongest predictors for acute stent thrombosis. No glycoprotein IIb/IIIa therapy and the use of drug-eluting stents were also associated with acute stent thrombosis. Lack of clopidogrel therapy in the first 30 days after the index PCI was the strongest predictor for subacute stent thrombosis. Mortality rates at 1-year follow-up were lower for acute stent thrombosis than for subacute stent thrombosis (8.3% vs. 13.2%, P = 0.294). The incidence of definite recurrent stent thrombosis at 1-year follow up was significantly lower after a first definite acute stent thrombosis than after a first definite subacute stent thrombosis (6.4% vs. 19.3%, P = 0.007 at 1 year).

CONCLUSIONS

The specific risk factors for, respectively, acute and subacute stent thrombosis after primary PCI vary greatly. Mortality rates are high for both categories of stent thrombosis. However, recurrent stent thrombosis occurs more frequently after subacute stent thrombosis.

Protein C and/or protein S deficiency and occurrence of stent thrombosis: a hitherto unrecognized association

OBJECTIVE

To study the prevalence of protein C and/or protein S deficiency in patients of stent thrombosis and correlate its association with the event, if any.

BACKGROUND

Stent thrombosis is the Achilles heel of percutaneous coronary intervention (PCI) and has been associated with so many predisposing factors that if one analyzes all patients undergoing PCI, one or more such factors would be present in almost every patient; however, its incidence remains no more than 1-2%. We hypothesized a preexisting prothrombotic state, or tendency, in a small proportion of patients that possibly plays a key role in its occurrence.

METHODS

We analyzed the prothrombotic tendency of individual patients by studying protein C and protein S levels. Thirteen patients presenting with stent thrombosis and 24 age- and sex-matched controls were studied.

RESULTS

Protein S was found to be deficient in 11 of 13 patients (84.6%) of stent thrombosis and in only 4 of 24 patients (16.7%) in matched controls (P < 0.001), while protein C was found deficient in 2 of 12 patients (16.7%) of stent thrombosis, and 1 of 24 patients (4.2%) in matched controls (P = 0.25) and either protein C or protein S was deficient in 11 of 13 (84.6%) of stent thrombosis and 5 of 24 (20.8%) controls (P = <0.001). Low protein S levels were strongly associated with stent thrombosis (odds ratio 3.04, 95% confidence interval 1.34-4.7) with sensitivity 0.73 and specificity of 0.91.

CONCLUSIONS

Protein S deficiency is strongly correlated to the occurrence of stent thrombosis, a fact that has hitherto not been recognized and needs further evaluation.

Delays in filling clopidogrel prescription after hospital discharge and adverse outcomes after drug-eluting stent implantation: implications for transitions of care

BACKGROUND

Adjuvant clopidogrel therapy is essential after drug-eluting stent (DES) implantation. The frequency with which patients delay filling a clopidogrel prescription after DES implantation and the association of this delay with adverse outcomes is unknown.

METHODS AND RESULTS

This was a retrospective cohort study of patients discharged after DES implantation from 3 large integrated health care systems. Filling a clopidogrel prescription was based on pharmacy dispensing data. The primary end point was all-cause mortality or myocardial infarction (MI). Of 7402 patients discharged after DES implantation, 16% (n=1210) did not fill a clopidogrel prescription on day of discharge and the median time delay was 3 days (interquartile range, 1 to 23 days). Compared with patients filling clopidogrel on day of discharge, patients with any delay in filling clopidogrel had higher death/MI rates during follow-up (14.2% versus 7.9%; P<0.001). In multivariable analysis, patients with any delay had increased risk of death/MI (hazard ratio, 1.53; 95% confidence interval, 1.25 to 1.87). Patients with any delay remained at increased risk of adverse outcomes when the delay cutoff was changed to >1, >3, or >5 days after discharge. Factors associated with delay included older age, prior MI, diabetes, renal failure, prior revascularization, cardiogenic shock, in-hospital bleeding, and clopidogrel use within 24 hours of admission.

CONCLUSIONS

One in 6 patients delay filling their index clopidogrel prescription after hospital discharge after DES implantation. This delay was associated with increased risk of adverse outcomes and highlights the importance of the transition period from hospital discharge to outpatient setting as a potential opportunity to improve care delivery and patient outcomes.

The incidence and clinical predictors of early stent thrombosis in patients with acute coronary syndrome

BACKGROUND

Acute coronary syndrome (ACS) is associated with activation of platelets and the coagulation system which could influence the incidence of early stent thrombosis (EST). We aimed to determine the incidence and predictors of EST in patients undergoing coronary stenting during ACS.

METHODS

The study comprised 1202 consecutive patients, drawn from a nationwide ACS survey, who underwent coronary stenting during ACS and were followed up for 30 days. Early stent thrombosis was based on the Academic Research Consortium definition.

RESULTS

Thirty patients (2.5%) sustained EST. The occurrence of EST in patients with unstable angina/non-ST-elevation myocardial infarction and ST-elevation myocardial infarction (STEMI) was 0.9% and 3.9%, respectively (P < .05), and was even higher (5.2%) in STEMI patients who underwent primary percutaneous coronary intervention. On multivariate analysis, STEMI (OR 6.3, 95% CI 2.1-18, P = .0008), multivessel disease (OR 5.9, 95% CI 1.9-21, P = .003) and Killip class >/=2 (OR 2.9, 95% CI 1.3-6.6, P = .008) were independent correlates of EST. The use of bare versus drug-eluting stents was not associated with any significant difference in EST.

CONCLUSIONS

Patients presenting with STEMI who are hemodynamically unstable and have multivessel coronary disease undergoing coronary stenting during ACS, are at increased risk of EST.

Baseline platelet size is increased in patients with acute coronary syndromes developing early stent thrombosis and predicts future residual platelet reactivity. A case-control study

INTRODUCTION

Pre-procedural predictors of early stent thrombosis (ST) and future response to platelet inhibitors are in demand. We sought to evaluate the impact of baseline platelet indices on the occurrence of early ST and future residual platelet reactivity.

MATERIALS AND METHODS

Hundred and eight patients with acute coronary syndromes (ACS) in whom stents were implanted were included: 36 consecutive ST cases and 72 matched controls. Platelet indices assessed with flow cytometry before stent implantation were retrieved from the department's data base. Residual platelet reactivity specific to aspirin (aspirin reaction units-ARU) and clopidogrel (P2Y12 reaction units-PRU) was assessed prospectively with VerifyNow under dual antiplatelet treatment.

RESULTS

Platelet size reported as mean platelet volume (MPV) or proportion of large platelets (LPLT) was significantly higher in ST cases compared with controls (10.4, 95% confidence intervals [CI], 10.1-10.8 vs. 9.7, CI, 9.5-9.9, P=0.0004 and 35.8, CI, 34.2-37.3 vs. 33.3, CI, 32.2-34.3, P=0.007, respectively). Dual aspirin and clopidogrel poor-responsiveness was diagnosed significantly more often in ST cases than in controls (19.6% vs. 1.4%, P=0.004), whereas no difference was observed for single aspirin or clopidogrel poor-responsiveness. A strong correlation was found between MPV and both, ARU (r=0.66, P<0.0001) and PRU (r=0.55, P<0.0001). Similarly, higher LPLT was associated with higher ARU (r=0.47, P<0.0001) and PRU (r=0.38, P=0.0001).

CONCLUSIONS

Baseline platelet size is increased in patients with ACS developing early ST and correlates with future residual platelet reactivity under aspirin and clopidogrel therapy. Dual but not isolated aspirin or clopidogrel poor-responsiveness appears to be associated with early ST.

Predictors of coronary stent thrombosis: the Dutch Stent Thrombosis Registry

OBJECTIVES

This study sought to comprehensively identify predictors of stent thrombosis (ST).

BACKGROUND

Given the devastating consequences of ST, efforts should be directed toward risk stratification to identify patients at highest risk for ST.

METHODS

Consecutive patients with angiographic ST were enrolled. Patients who did not suffer from a ST were randomly selected in a 2:1 ratio and were matched for: 1) percutaneous coronary intervention (PCI) indication; 2) same date of index PCI; and 3) same interventional center.

RESULTS

Of 21,009 patients treated with either a bare-metal or drug-eluting stent, 437 patients (2.1%) presented with a definite ST. A total of 140 STs were acute, 180 were subacute, 58 were late, and 59 were very late. Undersizing of the coronary stent, Thrombolysis In Myocardial Infarction flow grade <3, present malignancy, presence of intermediate coronary artery disease proximal and distal to the culprit lesion, dissection, lack of aspirin, bifurcation lesions, ejection fraction <30%, and younger age were associated with ST. The lack of clopidogrel therapy at the time of ST in the first 30 days after the index PCI (hazard ratio [HR]: 36.5, 95% confidence interval [CI]: 8.0 to 167.8), between 30 days and 6 months after the index PCI (HR: 4.6, 95% CI: 1.4 to 15.3), and beyond 6 months (HR: 5.9, 95% CI: 1.7 to 19.8) after the index PCI was strongly associated with ST.

CONCLUSIONS

Important correlates of ST were identified. Discontinuation of clopidogrel, undersizing of the coronary stent, present malignancy, and intermediate (>or=50% to <70% stenosis) coronary artery disease proximal to the culprit lesion were the strongest predictors of ST.

[Incidence of aspirin resistance in the patient group of a university hospital in Korea]

BACKGROUND

Aspirin is the most common drug used for the prevention of arterial thrombosis. However, platelet responsiveness to aspirin is variable among individuals and it is important to detect aspirin resistance to improve clinical outcome. We analyzed the changes of platelet reactivity before and after aspirin treatment. We also investigated the incidence and influencing factors of aspirin resistance in Korean.

METHODS

We tested platelet function in 198 patients who had been treated with aspirin in a Korean university hospital, and 59 of these patients were tested for platelet function before and after aspirin treatment. We also analyzed platelet reactivity in 136 patients who had not been treated with aspirin. Platelet function was tested using the VerifyNow Aspirin Assay (Accumetrics, USA). Platelet reactivity was expressed as aspirin reaction unit (ARU) and > or =550 ARU was defined as aspirin resistance.

RESULTS

Platelet reactivity of 136 patients who had not been treated with aspirin was 632.2plusmn;46.3 ARU (meanplusmn;SD) (range, 462-675). Platelet reactivity of 198 patients who had been treated with aspirin was 472.5plusmn;60.0 (338-666) ARU, and 10.1% of patients were aspirin-resistant. The difference of platelet reactivity before and after aspirin treatment was 128.3plusmn;68.7 (-40-248) ARU. Hb level was lower and platelet count was higher in aspirin-resistant group than in aspirin-sensitive group (P<0.05).

CONCLUSIONS

We demonstrated the distribution of platelet reactivity before and after aspirin treatment using the VerifyNow Aspirin Assay. The incidence of aspirin resistance was 10.1%, and low Hb level and high platelet count were related with aspirin resistance.