[Coronary stents: 30 years of medical progress]

The history of interventional cardiology has been marked by several technologic revolutions since the late 1970s. The first key step was the use of inflatable balloon angioplasty as an alternative to CABG surgery for coronary revascularization, followed by intracoronary delivery of bare metal stent (BMS) and drug eluting stents (DES) to drastically reduce intracoronary restenosis observed with BMS. Improved stents platforms and polymers (absorbable or biocompatible) led to a dramatic reduction in the rate of late stent thrombosis. Self-expanding stents are now available to improve stent a position especially in acute myocardial infarction. The emergence of new fully bioabsorbable stents that can be combined with antiproliferative drugs is the ongoing revolution. A new generation of stents is continuously improving and likely to become the ideal stent for coronary revascularization in the near future.

[Cardiology. Platelet function testing for clinicians]

Platelet P2YI2 receptor inhibition with clopidogrel, prasugrel or ticagrelor plays a key role to prevent recurrent ischaemic events after percutaneous coronary intervention in acute coronary syndromes or elective settings. The degree of platelet inhibition depends on the antiplatelet medication used and is influenced by clinical and genetic factors. A concept of therapeutic window exists. On one side, efficient anti-aggregation is required in order to reduce cardio-vascular events. On the other side, an excessive platelet inhibition represents a risk of bleeding complications. This article describes the current knowledge about some platelet function tests and genetic tests and summarises their role in the clinical practice.

A direct comparison of intravenous enoxaparin with unfractionated heparin in primary percutaneous coronary intervention (from the ATOLL trial)

Intravenous enoxaparin did not reduce significantly the primary end point (p = 0.06) compared with unfractionated heparin (UFH) in the randomized Acute Myocardial Infarction Treated with primary angioplasty and intravenous enoxaparin Or unfractionated heparin to Lower ischemic and bleeding events at short- and Long-term follow-up (ATOLL) trial. We present the results of the prespecified per-protocol analysis excluding patients who did not receive the treatment allocated by randomization or received both enoxaparin and UFH. We evaluated all-cause mortality, complication of myocardial infarction, procedural failure, or major bleeding (primary end point) and all-cause mortality, recurrent acute coronary syndrome, or urgent revascularization (main secondary end point). Baseline and procedural characteristics were well balanced between the 2 treatment groups. Of 910 randomized patients, 795 patients (87.4%) were treated according to the protocol with consistent anticoagulation using intravenous enoxaparin (n = 400) or UFH (n = 395). Enoxaparin reduced significantly the rates of the primary end point (relative risk [RR] 0.76, 95% confidence interval [CI] 0.62 to 0.94, p = 0.012) and the main secondary end point (RR 0.37, 95% CI 0.22 to 0.63, p <0.0001). There was less major bleeding with enoxaparin (RR 0.46, 95% CI 0.21 to 1.01, p = 0.050) contributing to the significant improvement of the net clinical benefit (RR 0.46, 95% CI 0.3 to 0.74, p = 0.0002). All-cause mortality was also reduced with enoxaparin (RR 0.36, 95% CI 0.18 to 0.74, p = 0.003). In conclusion, in the per-protocol analysis of the ATOLL trial, pertinent to >87% of the study population, enoxaparin was superior to UFH in reducing ischemic end points and mortality.

Pretreatment with prasugrel in non-ST-segment elevation acute coronary syndromes

BACKGROUND

Although P2Y12 antagonists are effective in patients with non-ST-segment elevation (NSTE) acute coronary syndromes, the effect of the timing of administration--before or after coronary angiography--is not known. We evaluated the effect of administering the P2Y12 antagonist prasugrel at the time of diagnosis versus administering it after the coronary angiography if percutaneous coronary intervention (PCI) was indicated.

METHODS

We enrolled 4033 patients with NSTE acute coronary syndromes and a positive troponin level who were scheduled to undergo coronary angiography within 2 to 48 hours after randomization. Patients were randomly assigned to receive prasugrel (a 30-mg loading dose) before the angiography (pretreatment group) or placebo (control group). When PCI was indicated, an additional 30 mg of prasugrel was given in the pretreatment group at the time of PCI and 60 mg of prasugrel was given in the control group.

RESULTS

The rate of the primary efficacy end point, a composite of death from cardiovascular causes, myocardial infarction, stroke, urgent revascularization, or glycoprotein IIb/IIIa inhibitor rescue therapy (glycoprotein IIb/IIIa bailout) through day 7, did not differ significantly between the two groups (hazard ratio with pretreatment, 1.02; 95% confidence interval [CI], 0.84 to 1.25; P=0.81). The rate of the key safety end point of all Thrombolysis in Myocardial Infarction (TIMI) major bleeding episodes, whether related or not related to coronary-artery bypass grafting (CABG), through day 7 was increased with pretreatment (hazard ratio, 1.90; 95% CI, 1.19 to 3.02; P=0.006). The rates of TIMI major bleeding and life-threatening bleeding not related to CABG were increased by a factor of 3 and 6, respectively. Pretreatment did not reduce the rate of the primary outcome among patients undergoing PCI (69% of the patients) but increased the rate of TIMI major bleeding at 7 days. All the results were confirmed at 30 days and in prespecified subgroups.

CONCLUSIONS

Among patients with NSTE acute coronary syndromes who were scheduled to undergo catheterization, pretreatment with prasugrel did not reduce the rate of major ischemic events up to 30 days but increased the rate of major bleeding complications. (Funded by Daiichi Sankyo and Eli Lilly; ACCOAST ClinicalTrials.gov number, NCT01015287.).

Ambulance or in-catheterization laboratory administration of ticagrelor for primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: rationale and design of the randomized, double-blind Administration of Ticagrelor in the cath Lab or in the Ambulance for New ST elevation myocardial Infarction to open the Coronary artery (ATLANTIC) study

Primary percutaneous coronary intervention (PCI) is the treatment of choice for patients presenting with acute ST-segment elevation myocardial infarction (STEMI). However, if catheterization facilities are not immediately available, the effectiveness of PCI can be affected by delays in transfer. Evidence suggests that antiplatelet therapy administered early, preferably in the ambulance during transfer, may provide better and earlier perfusion. Ticagrelor, a direct platelet P2Y12 receptor inhibitor, is indicated for the management of patients with acute coronary syndromes. The ATLANTIC study (NCT01347580; EudraCT 2011-000214-19) is a 30-day international, randomized, parallel-group, placebo-controlled study in male and female patients (aged ≥18 years) who are diagnosed as having STEMI, with intended primary PCI. In total, 1770 patients will be randomized immediately after diagnosis to prehospital administration of ticagrelor 180 mg followed by matching placebo administered in hospital, or prehospital administration of placebo followed by ticagrelor 180 mg administered in hospital. All patients will then receive ticagrelor 90 mg twice daily for 30 days. The coprimary end point is the percentage of patients reaching thrombolysis in myocardial infarction flow grade 3 in the infarct-related artery at initial angiography or achieving ≥70% ST-segment elevation resolution pre-PCI. The primary safety end point is major, life-threatening, or minor bleeding after ticagrelor administration. The results of this study may have an impact on future recommendations for treatment for patients with STEMI.

Prasugrel monitoring and bleeding in real world patients

The aim of this study was to evaluate platelet reactivity and 30-day bleeding events in patients treated with prasugrel 10 mg after acute coronary syndromes. A total of 444 patients with acute coronary syndromes treated with percutaneous coronary intervention and prasugrel 10 mg/day were monitored by measurement of the vasodilator-stimulated phosphoprotein (VASP) index 2 to 4 weeks after hospital discharge. Platelet reactivity was also assessed using the VerifyNow P2Y(12) assay and light transmission aggregometry. Bleeding events (per the Bleeding Academic Research Consortium [BARC] definition) and ischemic events (death, myocardial infarction, and definite stent thrombosis) were collected over 30 days of follow-up. Two thirds of the patients presented with ST-segment elevation myocardial infarctions, 28.8% had diabetes, and 12.4% were aged >75 years. High on-treatment platelet reactivity according to 3 prespecified definitions (VASP index ≥ 50%, platelet reactivity ≥ 235 P2Y(12) reaction units, and residual platelet reactivity ≥ 46.2%) was found in 6.8%, 3.4%, and 3.2% of patients, respectively. Obesity (body mass index >30 kg/m(2)) and multivessel disease were the only independent factors associated with high on-treatment platelet reactivity (p = 0.006 and p = 0.045, respectively). At 30 days, there was no major bleeding complication (BARC grade 3 or 5), and 1.6% of patients had recurrent ischemic events. Nuisance bleeding (BARC grade 1) and minor bleeding (BARC grade 2) occurred in 14.2% (n = 63) and 2.5% (n = 11) of patients, respectively, but were not predicted by VASP index. In conclusion, patients with acute coronary syndromes receiving maintenance doses of prasugrel have low rates of HPR and ischemic events within the first month. Minor or minimal bleeding is frequent, but not major bleeding. VASP was poorly correlated with the risk for minor or minimal bleeding.

Association of clopidogrel pretreatment with mortality, cardiovascular events, and major bleeding among patients undergoing percutaneous coronary intervention: a systematic review and meta-analysis

CONTEXT

Clopidogrel pretreatment is recommended for patients with acute coronary syndromes (ACS) and stable coronary artery disease who are scheduled for percutaneous coronary intervention (PCI), but whether using clopidogrel as a pretreatment for PCI is associated with positive clinical outcomes has not been established.

OBJECTIVE

To evaluate the association of clopidogrel pretreatment vs no treatment with mortality and major bleeding after PCI.

DATA SOURCES

MEDLINE, EMBASE, Cochrane Controlled Trials Register databases, and reference lists of qualifying articles. STUDY SELECTION Studies reporting clinical data on mortality and major bleeding were included. Of the 392 titles identified, 15 articles published between August 2001 and September 2012 met the inclusion criteria: 6 randomized controlled trials (RCTs), 2 observational analyses of RCTs, and 7 observational studies.

DATA EXTRACTION

Quality of studies was assessed with the Ottawa Scale and the Jadad Score as appropriate. Results were independently extracted by 2 reviewers. A random-effect model was applied. Pretreatment was defined as the administration of clopidogrel before PCI or catheterization. The main analysis was performed on RCTs and confirmed by observational analyses and observational studies. Prespecified subgroups--clinical presentation and clopidogrel loading dose--were analyzed. The primary efficacy and safety end points were all-cause mortality and major bleeding. Secondary end points included major cardiac events.

RESULTS

Of the 37 814 patients included in the meta-analysis, 8608 patients had participated in RCTs; 10,945, in observational analyses of RCTs; and 18,261, in observational studies. Analysis of RCTs showed that clopidogrel pretreatment was not associated with a reduction of death (absolute risk, 1.54% vs 1.97%; OR, 0.80; 95% CI, 0.57-1.11; P = .17) but was associated with a lower risk of major cardiac events (9.83% vs 12.35%; OR, 0 .77; 95% CI, 0.66-0.89; P < .001). There was no significant association between pretreatment and major bleeding overall (3 .57% vs 3.08%; OR, 1.18; 95% CI, 0.93-1.50; P = .18). Analyses from observational analyses of RCTs and observational studies were consistent for all results.

CONCLUSIONS

Among patients scheduled for PCI, clopidogrel pretreatment was not associated with a lower risk of mortality but was associated with a lower risk of major coronary events.

Bedside monitoring to adjust antiplatelet therapy for coronary stenting

BACKGROUND

Patients' responses to oral antiplatelet therapy are subject to variation. Bedside monitoring offers the opportunity to improve outcomes after coronary stenting by individualizing therapy.

METHODS

We randomly assigned 2440 patients scheduled for coronary stenting at 38 centers to a strategy of platelet-function monitoring, with drug adjustment in patients who had a poor response to antiplatelet therapy, or to a conventional strategy without monitoring and drug adjustment. The primary end point was the composite of death, myocardial infarction, stent thrombosis, stroke, or urgent revascularization 1 year after stent implantation. For patients in the monitoring group, the VerifyNow P2Y12 and aspirin point-of-care assays were used in the catheterization laboratory before stent implantation and in the outpatient clinic 2 to 4 weeks later.

RESULTS

In the monitoring group, high platelet reactivity in patients taking clopidogrel (34.5% of patients) or aspirin (7.6%) led to the administration of an additional bolus of clopidogrel, prasugrel, or aspirin along with glycoprotein IIb/IIIa inhibitors during the procedure. The primary end point occurred in 34.6% of the patients in the monitoring group, as compared with 31.1% of those in the conventional-treatment group (hazard ratio, 1.13; 95% confidence interval [CI], 0.98 to 1.29; P=0.10). The main secondary end point, stent thrombosis or any urgent revascularization, occurred in 4.9% of the patients in the monitoring group and 4.6% of those in the conventional-treatment group (hazard ratio, 1.06; 95% CI, 0.74 to 1.52; P=0.77). The rate of major bleeding events did not differ significantly between groups.

CONCLUSIONS

This study showed no significant improvements in clinical outcomes with platelet-function monitoring and treatment adjustment for coronary stenting, as compared with standard antiplatelet therapy without monitoring. (Funded by Allies in Cardiovascular Trials Initiatives and Organized Networks and others; ARCTIC ClinicalTrials.gov number, NCT00827411.).

Impact of transfer time on mortality in acute coronary syndrome with ST-segment elevation treated by angioplasty

BACKGROUND

In primary percutaneous coronary intervention (pPCI), conflicting data exist on the relative importance of patient presentation time (time from symptom onset (SO) to first medical contact [FMC]) and transfer time (time from FMC to sheath insertion).

OBJECTIVES

To evaluate the impact of transfer time on mortality in an unselected ST-elevation myocardial infarction (STEMI) population treated with pPCI.

METHODS

In a well-organized urban network, using mobile intensive care units (MICU) whenever possible, the impact of transfer time on inhospital mortality was evaluated in 703 unselected consecutive STEMI patients transferred for pPCI.

RESULTS

Our STEMI population included patients with cardiogenic shock (5.3%) and out-of-hospital cardiac arrest (3.7%). Longer transfer times were found to be associated with a stepwise increase in mortality ranging from 2.99% in the first quartile (Q1) up to 8.65% in the fourth quartile (Q4) (P=0.005). This result was noted in patients presenting early (≤2h of SO, 0.96% for Q1 vs. 9.8% for Q4, P=0.006) but not in late presenters (>2h of SO, 7.00% for Q1 vs. 7.8% for Q4, P=0.85). After adjustment for confounding variables such as the severity of patients, the relationship between mortality and transfer time was no longer apparent.

CONCLUSIONS

In a well-organized urban network dedicated to pPCI, including unselected STEMI patients, transfer time does not appear to be a major contributor to mortality. The relationship of transfer time to mortality seems to be dependent on presentation time and patients' clinical severity.

[Management of ST-elevation myocardial infarction in 2012]

Improvement of myocardial reperfusion with a greater use of primary percutaneous coronary intervention, adjunctive pharmacological and mechanical therapies have contributed to a spectacular decrease in mortality of patients presenting with ST-elevation myocardial infarction.

Current antiplatelet options for NSTE-ACS patients

Non-ST elevation (NSTE) myocardial infarction and unstable angina are the most common clinical presentations of acute coronary syndrome (ACS). Platelet activation is central to the pathogenesis of NSTE-ACS and consensus guidelines that advocate early revascularization supported by intensive antiplatelet therapy. This review examines the drugs used concurrently with aspirin as dual antiplatelet therapy in the NSTE-ACS setting. Clopidogrel represented an important therapeutic advance. However, variations in platelet response and a relatively slow onset of action compromise outcomes with clopidogrel. Evidence reviewed in this article shows that in NSTE-ACS patients, ticagrelor and prasugrel are more effective than clopidogrel and are relatively well tolerated, with an acceptable and manageable bleeding risk. The literature suggests several differences between ticagrelor and prasugrel that should allow clinicians to better tailor treatment to the patient. Head-to-head comparisons are now needed to compare directly the risks and benefits of ticagrelor and prasugrel in NSTE-ACS. Further studies also need to address other outstanding issues such as the benefits and risks of prasugrel pre-treatment and to stratify efficacy and tolerability according to diabetes mellitus (DM) and other co-morbidities. In the meantime, the issues discussed in this review should enhance clinicians' ability to optimize and individualize NSTE-ACS treatment, thereby further reducing the morbidity and mortality associated with this common cardiovascular condition.

Efficacy and safety of enoxaparin versus unfractionated heparin during percutaneous coronary intervention: systematic review and meta-analysis

OBJECTIVE

To determine the efficacy and safety of enoxaparin compared with unfractionated heparin during percutaneous coronary intervention.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline and Cochrane database of systematic reviews, January 1996 to May 2011.

STUDY SELECTION

Randomised and non-randomised studies comparing enoxaparin with unfractionated heparin during percutaneous coronary intervention and reporting on both mortality (efficacy end point) and major bleeding (safety end point) outcomes.

DATA EXTRACTION

Sample size, characteristics, and outcomes, extracted independently and analysed.

DATA SYNTHESIS

23 trials representing 30,966 patients were identified, including 10,243 patients (33.1%) undergoing primary percutaneous coronary intervention for ST elevation myocardial infarction, 8750 (28.2%) undergoing secondary percutaneous coronary intervention after fibrinolysis, and 11,973 (38.7%) with non-ST elevation acute coronary syndrome or stable patients scheduled for percutaneous coronary intervention. A total of 13,943 patients (45.0%) received enoxaparin and 17,023 (55.0%) unfractionated heparin. Enoxaparin was associated with significant reductions in death (relative risk 0.66, 95% confidence interval 0.57 to 0.76; P<0.001), the composite of death or myocardial infarction (0.68, 0.57 to 0.81; P<0.001), and complications of myocardial infarction (0.75, 0.6 to 0.85; P<0.001), and a reduction in incidence of major bleeding (0.80, 0.68 to 0.95; P=0.009). In patients who underwent primary percutaneous coronary intervention, the reduction in death (0.52, 0.42 to 0.64; P<0.001) was particularly significant and associated with a reduction in major bleeding (0.72, 0.56 to 0.93; P=0.01).

CONCLUSION

Enoxaparin seems to be superior to unfractionated heparin in reducing mortality and bleeding outcomes during percutaneous coronary intervention and particularly in patients undergoing primary percutaneous coronary intervention for ST elevation myocardial infarction.