Randomized Trial of High Loading Dose of Clopidogrel for Reduction of Periprocedural Myocardial Infarction in Patients Undergoing Coronary Intervention

Periprocedural myocardial infarction and injury

Periprocedural myocardial infarction (PMI) and injury, pertinent to both cardiac and non-cardiac procedures, have gained increasing recognition in clinical practice. Over time, diverse definitions for diagnosing PMI have been developed and validated among patient populations undergoing coronary revascularization. However, this variety in definitions presents considerable challenges in clinical settings and complicates both the design and interpretation of clinical trials. The necessity to accurately diagnose PMI has spurred significant interest in establishing universally accepted and prognostically meaningful thresholds for cardiac biomarkers elevation and supportive ancillary criteria. In fact, elevations in cardiac biomarkers in line with the 4th Universal Definition of Myocardial Infarction, have been extensively confirmed to be associated with increased mortality and cardiovascular events. In the context of non-coronary cardiac procedures, such as Transcatheter Aortic Valve Implantation, there is a growing acknowledgment of both the high incidence rates and the adverse impact of PMI on patient outcomes. Similarly, emerging research underscores the significance of PMI and injury in non-cardiac surgery, highlighting the urgent need for effective prevention and risk management strategies in this domain.

Canadian Cardiovascular Society/Canadian Association of Interventional Cardiology 2023 Focused Update of the Guidelines for the Use of Antiplatelet Therapy

Antiplatelet therapy (APT) is the foundation of treatment and prevention of atherothrombotic events in patients with atherosclerotic cardiovascular disease. Selecting the optimal APT strategies to reduce major adverse cardiovascular events, while balancing bleeding risk, requires ongoing review of clinical trials. Appended, the focused update of the Canadian Cardiovascular Society/Canadian Association of Interventional Cardiology guidelines for the use of APT provides recommendations on the following topics: (1) use of acetylsalicylic acid in primary prevention of atherosclerotic cardiovascular disease; (2) dual APT (DAPT) duration after percutaneous coronary intervention (PCI) in patients at high bleeding risk; (3) potent DAPT (P2Y12 inhibitor) choice in patients who present with an acute coronary syndrome (ACS) and possible DAPT de-escalation strategies after PCI; (4) choice and duration of DAPT in ACS patients who are medically treated without revascularization; (5) pretreatment with DAPT (P2Y12 inhibitor) before elective or nonelective coronary angiography; (6) perioperative and longer-term APT management in patients who require coronary artery bypass grafting surgery; and (7) use of APT in patients with atrial fibrillation who require oral anticoagulation after PCI or medically managed ACS. These recommendations are all on the basis of systematic reviews and meta-analyses conducted as part of the development of these guidelines, provided in the Supplementary Material.

P2Y12 Inhibitor Loading Time Before Elective PCI and the Prevention of Myocardial Necrosis

BACKGROUND

There are dated and conflicting data about the optimal timing of initiation of P2Y12 inhibitors in elective percutaneous coronary intervention (PCI). Peri-PCI myocardial necrosis is associated with poor outcomes. We aimed to assess the impact of the P2Y12 inhibitor loading time on periprocedural myocardial necrosis in the population of the randomized Assessment of Loading With the P2Y12 Inhibitor Ticagrelor or Clopidogrel to Halt Ischemic Events in Patients Undergoing Elective Coronary Stenting (ALPHEUS) trial, which compared ticagrelor with clopidogrel in high-risk patients who received elective PCI.

METHODS

The ALPHEUS trial divided 1809 patients into quartiles of loading time. The ALPHEUS primary outcome was used (type 4 [a or b] myocardial infarction or major myocardial injury) as well as the main secondary outcome (type 4 [a or b] myocardial infarction or any type of myocardial injury).

RESULTS

Patients in the first quartile group (Q1) presented higher rates of the primary outcome (P = 0.01). When compared with Q1, incidences of the primary outcome decreased in patients with longer loading times (adjusted odds ratio [adjOR], 0.70 [0.52.-0.95]; P = 0.02 for Q2; adjOR 0.65 [0.48-0.88]; P < 0.01 for Q3; adjOR 0.66 [0.49-0.89]; P < 0.01 for Q4). Concordant results were found for the main secondary outcome. There was no interaction with the study drug allocated by randomization (clopidogrel or ticagrelor). Bleeding complications (any bleeding ranging between 4.9% and 7.3% and only 1 major bleeding at 48 hours) and clinical ischemic events were rare and did not differ among groups.

CONCLUSIONS

In elective PCI, administration of the oral P2Y12 inhibitor at the time of PCI could be associated with more frequent periprocedural myocardial necrosis than an earlier administration. The long-term clinical consequences remain unknown.

Do We Still Need Aspirin in Coronary Artery Disease?

Aspirin has for some time been used as a first-line treatment for acute coronary syndromes, including ST-elevation myocardial infarction, for secondary prevention of established coronary disease, and for primary prevention in patients at risk of coronary artery disease. Although aspirin has been in use for decades, the available evidence for its efficacy largely predates the introduction of other drugs, such as statins and P2Y12 inhibitors. Based on recent trials, the recommendation for aspirin use as primary prevention has been downgraded. In addition, P2Y12 inhibitors given as a single antiplatelet therapy have been associated with a lower incidence of bleeding than dual antiplatelet therapy in combination with aspirin in patients with stable and unstable coronary artery disease. The aim of this review is to discuss the role of aspirin considering the available evidence for primary prevention, secondary prevention for stable coronary artery disease or acute coronary syndromes, and after percutaneous coronary intervention or coronary artery bypass revascularization.

Antiplatelet Therapy in Coronary Artery Disease: Now and Then

Cardiovascular disease, particularly coronary artery disease (CAD), remains the leading cause of mortality and morbidity in industrialized countries. Platelet activation and aggregation at the site of endothelial injury play a key role in the processes ultimately resulting in thrombus formation with vessel occlusion and subsequent end-organ damage. Consequently, antiplatelet therapy has become a mainstay in the pharmacological treatment of CAD. Several drug classes have been developed over the last decades and a broad armamentarium of antiplatelet agents is currently available. This review portrays the evolution of antiplatelet therapy, and provides an overview on previous and current antiplatelet drugs and strategies.

Clopidogrel Bolus is Inferior to Sustained Clopidogrel Pretreatment in Patients Undergoing Carotid Artery Stent Placement

BACKGROUND

Clopidogrel bolus is an option used before carotid artery stent (CAS) placement when sustained clopidogrel pretreatment is not used.

OBJECTIVE

To compare the effect of clopidogrel bolus (450 mg administered ≥4 hours) with sustained clopidogrel pretreatment (48 hours or greater) before CAS among patients recruited in the Carotid Revascularization Endarterectomy versus Stenting Trial.

METHODS

We compared the rates of primary end point (either any stroke, myocardial infarction, or death during the periprocedural period or any ipsilateral stroke within 4 years) between patients who received clopidogrel bolus and those who received sustained clopidogrel pretreatment using Cox proportional hazards analysis after adjusting for age, sex, symptomatic status, and initial severity of stenosis (≥70% vs <70%) over 4 years.

RESULTS

The rate of periprocedural stroke (7.3% vs 3.4%, P = .03) and primary end point (11.3% vs 5.9%, P = .02) was significantly higher among patients who received clopidogrel bolus. The risk of primary end point was significantly higher in patients who received clopidogrel bolus (hazards ratio 1.9, 95% CI 1.1-3.4, P = .02) after adjusting for potential confounders. The overall mean (±standard deviation) primary end point-free survival based on Kaplan-Meier analysis was 7.0 ± 0.2 years for patients who received clopidogrel bolus and 8.9 ± 0.1 years for those who received sustained clopidogrel pretreatment (log-rank test P = .011).

CONCLUSION

Clopidogrel bolus was associated with higher rates of adverse outcomes compared with sustained clopidogrel pretreatment in patients who underwent CAS. Therefore, clopidogrel bolus may not be equivalent to sustained clopidogrel pretreatment.

A fresh look at coronary microembolization

Mechanical stress from haemodynamic perturbations or interventional manipulation of epicardial coronary atherosclerotic plaques with inflammatory destabilization can release particulate debris, thrombotic material and soluble substances into the coronary circulation. The physical material obstructs the coronary microcirculation, whereas the soluble substances induce endothelial dysfunction and facilitate vasoconstriction. Coronary microvascular obstruction and dysfunction result in patchy microinfarcts accompanied by an inflammatory reaction, both of which contribute to progressive myocardial contractile dysfunction. In clinical studies, the benefit of protection devices to retrieve atherothrombotic debris during percutaneous coronary interventions has been modest, and the treatment of microembolization has mostly relied on antiplatelet and vasodilator agents. The past 25 years have witnessed a relative proportional increase in non-ST-segment elevation myocardial infarction in the presentation of acute coronary syndromes. An associated increase in the incidence of plaque erosion rather than rupture has also been recognized as a key mechanism in the past decade. We propose that coronary microembolization is a decisive link between plaque erosion at the culprit lesion and the manifestation of non-ST-segment elevation myocardial infarction. In this Review, we characterize the features and mechanisms of coronary microembolization and discuss the clinical trials of drugs and devices for prevention and treatment.

Effects of Danhong Injection () on Peri-Procedural Myocardial Injury and Microcirculatory Resistance in Patients with Unstable Angina Undergoing Elective Percutaneous Coronary Intervention: A Pilot Randomized Study

OBJECTIVE

To evaluate the effect of Danhong Injection (, DH) on the index of microcirculatory resistance (IMR) and myocardial injury in patients with unstable angina undergoing elective percutaneous coronary intervention (PCI).

METHODS

Seventy-eight patients with unstable angina were randomly divided into DH group (39 cases) and the control group (39 cases) during elective PCI. Randomization was performed using a random-number table. The DH group received DH at a dosage of 40 mL (mixed with 250 mL saline, covered by a light-proof bag, intravenous drip) during PCI and daily for 7 consecutive days, while the control group only received the same dosage of saline. Both groups received standardized treatment. The IMR and fractional flow reserve (FFR) were measured at maximal hyperemia before and after PCI. Myocardial markers, including myoglobin, creatine kinase (CK), creatine kinase MB (CK-MB), and coronary troponin T (cTnT) values were measured at baseline and 24 h after PCI.

RESULTS

Among the 78 patients enrolled, the baseline and procedural characteristics were similar between the two groups. There was no significant difference in pre-PCI myocardial markers and coronary physiological indexes between the two groups. However, post-PCI CK and CK-MB levels in the DH group were significantly lower than those in the control group (111.97 ± 80.97 vs. 165.47 ± 102.99, P=0.013; 13.08 ± 6.90 vs. 19.75 ± 15.49, P=0.016). Post-PCI myoglobin and cTNT-positive tend to be lower in the DH group than in the control group but did not reach statistical significance (88.07 ± 52.36 vs. 108.13 ± 90.94, P=0.52; 2.56% vs.7.69%, P=0.065). Compared with the control group, the post-IMR levels of the DH group tended to decrease, but there was no statistical difference (20.73 ± 13.15 vs. 26.37 ± 12.31, P=0.05). There were no statistical differences in post-FFR in both groups. The peri-procedural myocardial injury of the DH group was significantly lower than that of the control group (2.56% vs. 15.38%, P=0.025). During the 30-d follow-up period, no major adverse cardiovascular events occurred in either group.

CONCLUSION

This study demonstrated benefit of DH in reducing myocardial injury and potential preserving microvascular function in patients with unstable angina undergoing elective PCI.

7-Difluoromethoxy-5,4'-dimethoxy-genistein attenuates macrophages apoptosis to promote plaque stability via TIPE2/TLR4 axis in high fat diet-fed ApoE-/- mice

Promoting plaque stability is of great significance for prevention and treatment of cardiovascular diseases. 7-difluoromethoxy-5,4'-dimethoxygenistein (DFMG) is a novel active compound synthesized using genistein, which exerts anti-atherosclerotic effect. In this study, we evaluated effects of DFMG on plaque stability in ApoE^-/- mice fed with high fat diet (HFD), and explored the molecular mechanism by using ApoE^-/-TLR4^-/- mice and RAW264.7 cells. Here, we found that DFMG significantly reduced plaque areas, macrophages infiltration and apoptosis, and TLR4 expression in HFD-fed ApoE^-/- mice. Meanwhile, DFMG increased collagen fibers, smooth muscle cells and TIPE2 expression in plaques and media. Besides, TLR4 knockout promoted the protective effects of DFMG on plaques. In vitro, DFMG decreased lysophosphatidylcholine (LPC)-induced macrophages apoptosis and TLR4, while upregulated TIPE2. Moreover, TIPE2 reduced TLR4, MyD88, p-NF-κB p65^Ser276, cleaved Caspase-3 overproduction, and enhanced effects of DFMG on LPC-induced macrophages. Overall, our study demonstrates that DFMG can promote plaque stability by reducing macrophage apoptosis through TIPE2/TLR4 signaling pathway, which suggests DFMG should be used to develop food additives or drugs for preventing atherosclerosis.

Periprocedural Myocardial Injury: Pathophysiology, Prognosis, and Prevention

The definition and clinical implications of myocardial infarction occurring in the setting of percutaneous coronary intervention have been the subject of unresolved controversy. The definitions of periprocedural myocardial infarction (PMI) are many and have evolved over recent years. Additionally, the recent advancement of different imaging modalities has provided useful information on a patients' pre-procedural risk of myocardial infarction. Nonetheless, questions on the benefit of different approaches to prevent PMI and their practical implementation remain open. This review aims to address these questions and to provide a current and contemporary perspective.

The Role of Clopidogrel in 2020: A Reappraisal

Antiplatelet therapy is the mainstay of treatment and secondary prevention of cardiovascular disease (CVD), including acute coronary syndrome (ACS), transient ischemic attack (TIA) or minor stroke, and peripheral artery disease (PAD). The P2Y12 inhibitors, of which clopidogrel was the first, play an integral role in antiplatelet therapy and therefore in the treatment and secondary prevention of CVD. This review discusses the available evidence concerning antiplatelet therapy in patients with CVD, with a focus on the role of clopidogrel. In combination with aspirin, clopidogrel is often used as part of dual antiplatelet therapy (DAPT) for the secondary prevention of ACS. Although newer, more potent P2Y12 inhibitors (prasugrel and ticagrelor) show a greater reduction in ischemic risk compared with clopidogrel in randomized trials of ACS patients, these newer P2Y12 inhibitors are often associated with an increased risk of bleeding. Deescalation of DAPT by switching from prasugrel or ticagrelor to clopidogrel may be required in some patients with ACS. Furthermore, real-world studies of ACS patients have not confirmed the benefits of the newer P2Y12 inhibitors over clopidogrel. In patients with very high-risk TIA or stroke, short-term DAPT with clopidogrel plus aspirin for 21-28 days, followed by clopidogrel monotherapy for up to 90 days, is recommended. Clopidogrel monotherapy may also be used in patients with symptomatic PAD. In conclusion, there is strong evidence supporting the use of clopidogrel antiplatelet therapy in several clinical settings, which emphasizes the importance of this medication in clinical practice.

Three-dimensional assessment of coronary high-intensity plaques with T1-weighted cardiovascular magnetic resonance imaging to predict periprocedural myocardial injury after elective percutaneous coronary intervention

BACKGROUND

Periprocedural myocardial injury (pMI) is a common complication of elective percutaneous coronary intervention (PCI) that reduces some of the beneficial effects of coronary revascularization and impacts the risk of cardiovascular events. We developed a 3-dimensional volumetric cardiovascular magnetic resonance (CMR) method to evaluate coronary high intensity plaques and investigated their association with pMI after elective PCI.

METHODS

Between October 2012 and October 2016, 141 patients with stable coronary artery disease underwent T1-weighted CMR imaging before PCI. A conventional 2-dimensional CMR plaque-to-myocardial signal intensity ratio (2D-PMR) and the newly developed 3-dimensional integral of PMR (3Di-PMR) were measured. 3Di-PMR was determined as the sum of PMRs above a threshold of > 1.0 for voxels in a target plaque. pMI was defined as high-sensitivity cardiac troponin T > 0.07 ng/mL.

RESULTS

pMI following PCI was observed in 46 patients (33%). 3Di-PMR was significantly higher in patients with pMI than those without pMI. The optimal 3Di-PMR cutoff value for predicting pMI was 51 PMR*mm3 and the area under the receiver operating characteristic curve (0.753) was significantly greater than that for 2D-PMR (0.683, P = 0.015). 3Di-PMR was positively correlated with lipid volume (r = 0.449, P < 0.001) based on intravascular ultrasound. Stepwise multivariable analysis showed that 3Di-PMR ≥ 51 PMR*mm3 and the presence of a side branch at the PCI target lesion site were significant predictors of pMI (odds ratio [OR], 11.9; 95% confidence interval [CI], 4.6-30.4, P < 0.001; and OR, 4.14; 95% CI, 1.6-11.1, P = 0.005, respectively).

CONCLUSIONS

3Di-PMR coronary assessment facilitates risk stratification for pMI after elective PCI.

TRIAL REGISTRATION

retrospectively registered.

What Are Optimal P2Y12 Inhibitor and Schedule of Administration in Patients With Acute Coronary Syndrome?

Guidelines recommend treatment with a P2Y12 platelet adenosine diphosphate receptor inhibitor in patients undergoing elective or urgent percutaneous coronary intervention (PCI), but the optimal agent or timing of administration is still not clearly specified. The P2Y12 inhibitor was initially used for its platelet anti-aggregatory action to block thrombosis of the recanalized coronary artery or deployed stent. It is now recognized that these agents also offer potent cardioprotection against a reperfusion injury that occurs in the first minutes of reperfusion if platelet aggregation is blocked at the time of reperfusion. But this is difficult to achieve with oral agents which are slowly absorbed and often require time-consuming metabolic activation. Patients with ST-segment elevation myocardial infarction who usually have a large mass of myocardium at risk of infarction seldom have sufficient time for upstream-administered oral agents to achieve a therapeutic P2Y12 level of inhibition by the time of balloon inflation. However, optimal treatment could be assured by initiating an IV cangrelor infusion shortly prior to stenting followed by subsequent post-PCI transition to an oral agent, that is, ticagrelor, once success of the recanalization and absence of need for surgical intervention are confirmed. Not only should this sequence provide optimal protection against infarction, it should also negate bleeding if coronary artery bypass grafting should be required since stopping the cangrelor infusion at any time will quickly restore platelet reactivity. It is anticipated that cangrelor-induced myocardial salvage will help preserve myocardial function and significantly diminish postinfarction heart failure.

Usefulness of Clopidogrel Loading in Patients Who Underwent Transcatheter Aortic Valve Implantation (from the BRAVO-3 Randomized Trial)

P2Y₁₂-inhibitor initiation with clopidogrel using a loading dose (LD) versus no LD (NLD) provides more rapid inhibition of platelet activation and reduced risk of ischemic events after coronary stenting. Whether a similar beneficial effect is achieved in the setting of transcatheter aortic valve implantation (TAVI) is unknown. We evaluate the effects of preprocedural clopidogrel LD versus no NLD on 48-hour and 30-day clinical outcomes after TAVI. In the BRAVO-3 trial, 802 patients with severe aortic stenosis who underwent transfemoral TAVI were randomized to intraprocedural anticoagulation with bivalirudin or unfractionated heparin. Administration of clopidogrel LD was left to the discretion of the treating physician. For this analysis, patients were stratified according to receiving clopidogrel LD (n = 294, 36.6%) or NLD (n = 508, 63.4%) before TAVI. LD patients more often received a self-expandable prosthesis using larger sheaths. P2Y₁₂-inhibitor maintenance therapy pre-TAVI was similar in patients with LD versus NLD (28.2% vs 33.1%, p = 0.16). LD versus NLD was associated with similar incidences of major adverse cardiovascular events (i e., death, myocardial infarction, or stroke) (4.1% vs 4.1%, p = 0.97) and major bleeding (8.5% vs 7.7%, p = 0.68), but a higher rate of major vascular complications (11.9% vs 7.1%, p = 0.02). Multivariable adjustment showed that clopidogrel LD did not affect any of the studied clinical events, including major vascular complications (odds ratio 0.91, 95% confidence interval 0.60 to 1.39, p = 0.67). Also patients on clopidogrel maintenance therapy and thus considered in steady state were not at reduced risk of major adverse cardiovascular events compared with patients not on clopidogrel (3.7% vs 5.2%, p = 0.36). In conclusion, in patients who underwent TAVI, use of clopidogrel LD was associated with higher vascular complications and otherwise similar clinical events compared to NLD patients.

Prevention of atherothrombotic events in patients with diabetes mellitus: from antithrombotic therapies to new-generation glucose-lowering drugs

Diabetes mellitus is an important risk factor for a first cardiovascular event and for worse outcomes after a cardiovascular event has occurred. This situation might be caused, at least in part, by the prothrombotic status observed in patients with diabetes. Therefore, contemporary antithrombotic strategies, including more potent agents or drug combinations, might provide greater clinical benefit in patients with diabetes than in those without diabetes. In this Consensus Statement, our Working Group explores the mechanisms of platelet and coagulation activity, the current debate on antiplatelet therapy in primary cardiovascular disease prevention, and the benefit of various antithrombotic approaches in secondary prevention of cardiovascular disease in patients with diabetes. While acknowledging that current data are often derived from underpowered, observational studies or subgroup analyses of larger trials, we propose antithrombotic strategies for patients with diabetes in various cardiovascular settings (primary prevention, stable coronary artery disease, acute coronary syndromes, ischaemic stroke and transient ischaemic attack, peripheral artery disease, atrial fibrillation, and venous thromboembolism). Finally, we summarize the improvements in cardiovascular outcomes observed with the latest glucose-lowering drugs, and on the basis of the available evidence, we expand and integrate current guideline recommendations on antithrombotic strategies in patients with diabetes for both primary and secondary prevention of cardiovascular disease.

Preintensive care: Thrombolytic (streptokinase or tenecteplase) in ST elevated acute myocardial infarction at peripheral hospital

Background:

Coronary artery disease is a major cause of death in India. Sudden death preceded by chest pain is due to acute myocardial infarction. Villagers are aware and afraid of chest pain. Majority of chest pain victims attend the primary physician in golden hours. Hence, primary doctors can play important role for early thrombolysis and salvage the myocardium from irreversible injury. This study determined year mortality in a patient who received the rapid thrombolysis at primary care hospital (streptokinase or tenecteplase) at rural setting.

Setting:

Peripheral General Hospital Mahad on Mumbai–Goa highway.

Patients and Methods:

Patients with typical chest pain with electrocardiogram showed ST segment elevated myocardial infarction (STEMI) with or without risk factors admitted from 2005 to march 2016 were studied. Details clinically studied: time interval between chest pain to hospital, hospital to needle time, reperfusion and arrhythmias. Time required for regression of elevated ST segment, a response to thrombolytic (streptokinase or tenecteplase) therapy, is studied.

Results:

Total 244 patient reported with chest pain of these 35 cases brought dead with history of chest pain and convulsive moment before they died. Of these, 209 patients had acute STEMI. Of these, 162 received streptokinase (STK) and 47 received tenecteplase (TNP)]. Analysis of STK Vs TNP patients 18 (11.11%) versus 3 (6.38%) (P = 0.361) died during the treatment. Around 17 (18.49%) vs 5 (10.63%) (P = 0.941) did not show signs of reperfusion, respectively. Re infarction occurred during hospitalization 3 (2.5%) versus 3 (6.38%) (P = 0.094) cases. Around 12 (7.40%) versus 0% (P = 0.072) died at the end of 12 months of thrombolytic therapy.

Conclusion:

Thrombolysis of STEMI within golden hours improved the reperfusion. However, 1-year fatality is significance with streptokinase as compared with tenecteplase.

Colonoscopy, Polypectomy, and the Risk of Bleeding

Colonoscopy with polypectomy is the means by which the incidence of colon cancer may be reduced; however, polypectomy is not without risk. Physicians must carefully weigh the risks and benefits of colonoscopy, particularly when patients are given prescriptions for antiplatelet agents and anticoagulants. This article discusses the risks of colonoscopy and polypectomy and reviews the most recent data for managing antiplatelet agents and anticoagulants in the periendoscopic period.

Cardiac Troponin - diagnostic problems and impact on cardiovascular disease

The definition of a high-sensitivity cardiac Troponin (cTn) assay describes the ability to quantify a cardiac biomarker level in at least 50% of healthy individuals. This advance in analytic sensitivity has come with a perceived loss of specificity in the most classic application - chest pain triage and the diagnosis of acute myocardial infarction (AMI). As cardiac Troponin can no longer be used as a dichotomous test, the medical field is increasingly moving towards a more granular interpretation. However, rapid rule-out/rule-in algorithms for AMI still rely on concrete thresholds for efficient triage, irrespective of the patient's comorbidities. Owing to a slightly elevated cTn value, evermore patients appear to fall into an indeterminate risk zone of diagnostic uncertainty. The reasons are manifold, spanning biological variation, analytical issues, increased plasma membrane permeability and the potential cytosolic release of cTn. This review provides a contemporary overview of the literature concerning the use of cardiac Troponin in chronic and acute cardiovascular care. Key messages High-sensitivity cardiac Troponin assays have transformed the assessment of cardiovascular disease. Rapid rule-out algorithms for chest pain triage have become increasingly complicated, but enable safe rule-out. Cardiac Troponin tracks mid- to long-term risk in patients with hyperlipidaemia, heart failure and renal dysfunction.

Management of Anticoagulants and Antiplatelet Agents During Colonoscopy

Colonoscopy frequently is performed for patients who are taking aspirin, nonsteroidal anti-inflammatory drugs, antiplatelet agents, and other anticoagulants. These colonoscopies often involve polypectomy, which can be complicated by bleeding. The risks of precipitating thromboembolic complications if anticoagulants are stopped must be weighed against the risk of postpolypectomy bleeding if these agents are continued. This article systematically reviews the management of anticoagulation during elective and emergency colonoscopy. For patients undergoing colonoscopic polypectomy, the overall risk of postpolypectomy bleeding is <0.5%. Risk factors for postpolypectomy bleeding include large polyp size and anticoagulant use, especially warfarin and thienopyridines. For patients who do not stop aspirin or other nonsteroidal anti-inflammatory drugs prior to colonoscopy, the rate of postpolypectomy bleeding is not significantly different from that for patients who do not take those medications. For patients who continue thienopyridines and undergo polypectomy, the risk of delayed postpolypectomy bleeding is approximately 2.4%. Even for patients who interrupt warfarin, the risk of postpolypectomy bleeding is increased. The direct oral anticoagulants (direct thrombin inhibitors and factor Xa inhibitors) have a rapid onset and offset of action, and periprocedural bridging generally is not necessary. For the thienopyridines, warfarin, and the direct oral anticoagulants, the decision to interrupt or continue these agents for endoscopy will involve considerable exercise of clinical judgment.

Administration of Ticagrelor and Double-Dose Clopidogrel Based on Platelet Reactivity Determined by VerifyNow-P2Y12 for Chinese Subjects After Elective PCI

Previous studies have identified high on treatment platelet reactivity (HTPR) as a potent factor predicting ischemic events for patients with coronary heart disease. We assessed the efficacy and safety of ticagrelor (90 mg twice-daily) and double-dose of clopidogrel (150 mg once-daily) among Chinese patients for elective percutaneous coronary intervention. We enrolled 40 patients with HTPR from among 317 patients with non-ST-segment elevation acute coronary syndromes after a successful elective percutaneous coronary intervention (PCI). Platelet reactivity was measured by VerifyNow P2Y12 assay. Platelet reactivity was significantly lower for both groups when compared with baseline platelet reactivity after medication adjustment (all P < 0.001). The mean platelet reactivity units (PRU) was significantly lower for the ticagrelor group compared with that of the clopidogrel group over time (all P < 0.001). The differences in the rate of sustained HTPR at different time points between the two groups were significant (2 hours: 0% versus 60%; 8 hours: 5.6% versus 50%; 24 hours: 5.9% versus 43.8%, all P < 0.05). Genetic variation of CYP2C19*2 had no impact on PRU means or rate of HTPR in the ticagrelor group (P > 0.05). During the 30-day follow-up, no MACE occurred in any patient, and the overall risk of bleeding showed no difference between the two groups (35% versus 21%, P = 0.48). Our results suggest that ticagrelor may achieve a more rapid and greater platelet inhibition than double-dose clopidogrel. Further studies are still needed to assess the differences in efficacy and safety between ticagrelor and double-dose clopidogrel administration for Chinese patients post elective PCI.

Safety and efficacy of policosanol in patients with high on-treatment platelet reactivity after drug-eluting stent implantation: two-year follow-up results

OBJECTIVES

To investigate safety and efficacy of policosanol in patients with high on-treatment platelet reactivity after drug-eluting stent implantation.

BACKGROUND

Certain number of patients has high residual platelet reactivity on clopidogrel after coronary intervention, and their risk of thrombotic events is high.

METHOD

In this prospective, randomized trial conducted in four Chinese sites, 350 patients with high on-treatment platelet reactivity (HPR, defined as platelet aggregation >65%) were randomized by the ratio of 1:3:3 to: group A, clopidogrel 75 mg/d for 1 year (n=50); group B, clopidogrel 150 mg/d for 30 days followed by 75 mg/d until 1 year (n=150); or group C, policosanol 40 mg/d for 6 month and clopidogrel 75 mg/d for 1 year (n=150). All of them were treated with aspirin. The primary endpoint was the reversion rate of HPR at 1 month (reversion was defined as platelet aggregation <65%). The secondary endpoints were 6-month major adverse cardiac events (MACE), which included cardiac death, nonfatal myocardial infarction, or ischemic symptoms driven target vessel revascularization.

RESULTS

At 30 days, the reversion rate of HPR was 34.0%, 55.2%, and 48.7% in group A, group B, and group C, respectively (P=.029). Major adverse cardiac events occurred in 4 (8.0%), 6(4.0%), and 5(3.3%) patients (P=.342). There was 1 (0.7%) major bleeding and 1 (0.7%) minor bleeding event in high maintenance dose clopidogrel group, no major or moderate bleeding in the other two groups. The minimal bleeding in group B was significantly higher than group C (10.7% vs 2.7%, P=.022). At 2-year follow-up, the benefits of policosanol on bleedings persisted compared with group B.

CONCLUSIONS

Policosanol reduced platelet reactivity to a similar extent as high maintenance dose of clopidogrel without increasing bleeding rate.

Acute myocardial infarction

Acute myocardial infarction has traditionally been divided into ST elevation or non-ST elevation myocardial infarction; however, therapies are similar between the two, and the overall management of acute myocardial infarction can be reviewed for simplicity. Acute myocardial infarction remains a leading cause of morbidity and mortality worldwide, despite substantial improvements in prognosis over the past decade. The progress is a result of several major trends, including improvements in risk stratification, more widespread use of an invasive strategy, implementation of care delivery systems prioritising immediate revascularisation through percutaneous coronary intervention (or fibrinolysis), advances in antiplatelet agents and anticoagulants, and greater use of secondary prevention strategies such as statins. This seminar discusses the important topics of the pathophysiology, epidemiological trends, and modern management of acute myocardial infarction, focusing on the recent advances in reperfusion strategies and pharmacological treatment approaches.

Effect of Pretreatment with Omega-3 Supplement on Cardiac Necrosis Markers in Chronic Kidney Disease Patients Undergoing Elective Percutaneous Coronary Intervention

Objective:

Studies have demonstrated the direct relation between elevation in cardiac necrosis markers and increased risk of cardiovascular complications after percutaneous coronary intervention (PCI) in chronic kidney disease (CKD) patients. In this study, we sought to evaluate the effect of omega-3 on creatine kinase-MB (CK-MB) and troponin-I in CKD patients undergoing elective PCI.

Methods:

Eighty CKD patients, candidate for elective PCI, were randomly assigned into two groups: Group A – receiving omega-3 (2.5 g, 12 h before PCI) plus standard treatment (n = 37) and Group B – control group, receiving only standard therapy (aspirin 325 mg and clopidogrel 600 mg loading dose and weight-adjusted intravenous heparin) (n = 43). Blood samples were collected before and 24 h after PCI for measuring CK-MB and troponin-I. The primary endpoint was considered to be postprocedural variations of CK-MB and troponin-I levels in both groups. The secondary endpoint was the percentage of pre-procedural myocardial infarction (PMI) occurrence, defined as the elevation of post-PCI troponin-I, between study groups.

Findings:

Both the baseline and 24-h CK-MB were significantly higher in omega-3 group. Although 24-h troponin-I increased less in omega-3-treated arm compared to the control group, no statistically significant variation was observed between the two groups. With regard to PMI occurrence, no significant difference was detected among study groups.

Conclusion:

Despite the beneficial but nonsignificant effects of omega-3 on decreasing post-PCI elevation of troponin-I and PMI occurrence, further investigations with bigger study population, higher doses of omega-3 and longer duration of treatment, and long-term follow-up of patients are required to better test the potential effects of omega-3 in improving clinical outcomes in CKD patients undergoing PCI.

P2Y12 Inhibitor Pre-Treatment in Non-ST-Elevation Acute Coronary Syndrome: A Decision-Analytic Model

Current guidelines recommend initiation of a P2Y12 inhibitor for all patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) at the time of diagnosis (pre-treatment); however, there are no randomized trials directly comparing pre-treatment with initiation at the time of angiography to support this practice. We explore clinical and institutional parameters potentially associated with benefit with this strategy in a decision-analytic model based on available evidence from randomised trials. A decision analysis model was constructed comparing three P2Y12 inhibitors in addition to aspirin in patients with NSTE-ACS. Based on clinical trial data, the cumulative probability of 30 day mortality, myocardial infarction (MI) and major bleeding were determined, and used to calculate the net clinical benefit (NCB) with and without pre-treatment. Sensitivity analysis was performed to assess the relationship between NCB and baseline ischemic risk, bleeding risk, time to angiography and local surgical revascularization rates. Pre-treatment with ticagrelor and clopidogrel was associated with a greater than 50% likelihood of providing a >1% increase in 30 day NCB when baseline estimated ischemic risk exceeds 11% and 14%, respectively. Prasugrel pre-treatment did not achieve a greater than 50% probability of an increase in NCB regardless of baseline ischemic risk. Institutional surgical revascularization rates and time to coronary angiography did not correlate with the likelihood of benefit from P2Y12 pre-treatment. In conclusion, pre-treatment with P2Y12 inhibition is unlikely to be beneficial to the majority of patients presenting with NSTE-ACS. A tailored assessment of each patient's individual ischemic and bleeding risk may identify those likely to benefit.

Does Pre-Treatment with High Dose Atorvastatin Prevent Microvascular Dysfunction after Percutaneous Coronary Intervention in Patients with Acute Coronary Syndrome?

Background and Objectives

There is controversy surrounding whether or not high dose statin administration before percutaneous coronary intervention (PCI) decreases peri-procedural microvascular injury. We performed a prospective randomized study to investigate the mechanisms and effects of pre-treatment high dose atorvastatin on myocardial damage in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) undergoing PCI.

Subjects and Methods

Seventy seven patients with NSTE-ACS were randomly assigned to either the high dose group (atorvastatin 80 mg loading 12 to 24 h before PCI with a further 40 mg loading 2 h before PCI, n=39) or low dose group (atorvastatin 10 mg administration 12 to 24 h before PCI, n=38). Index of microcirculatory resistance (IMR) was measured after stent implantation. Creatine kinase-myocardial band (CK-MB) and high sensitivity C-reactive protein (CRP) levels were measured before and after PCI.

Results

The baseline characteristics were not different between the two patient groups. Compared to the low dose group, the high dose group had lower post PCI IMR (14.1±5.0 vs. 19.2±9.3 U, p=0.003). Post PCI CK-MB was also lower in the high dose group (median: 1.40 ng/mL (interquartile range [IQR: 0.75 to 3.45] vs. 4.00 [IQR: 1.70 to 7.37], p=0.002) as was the post-PCI CRP level (0.09 mg/dL [IQR: 0.04 to 0.16] vs. 0.22 [IQR: 0.08 to 0.60], p=0.001).

Conclusion

Pre-treatment with high dose atorvastatin reduces peri-PCI microvascular dysfunction verified by post-PCI IMR and exerts an immediate anti-inflammatory effect in patients with NSTE-ACS.

Effect of a combination of antiplatelet and antithrombotic pretreatment on myocardial perfusion in patients with an acute ST-segment elevation myocardial infarction undergoing a primary percutaneous coronary intervention

INTRODUCTION

Primary percutaneous coronary intervention (PCI) is the preferred method of reperfusion in ST-segment elevation myocardial infarction patients. Adjunctive pharmacotherapy is, however, still under investigation.

OBJECTIVE

To assess the effect of combined pharmacologic therapy on myocardial perfusion and infarct size in relation to time delays.

MATERIALS AND METHODS

We studied 309 consecutive ST-segment elevation myocardial infarction patients admitted within 12 h from symptom onset with (a) chest pain persisting for more than 30 min, (b) ST-segment elevation more than 1 mm in at least two contiguous leads, and (c) pretreatment with 600 mg of clopidogrel, 300 mg of aspirin, and 5000 U of intravenous heparin. Group I (n=90) included patients transferred directly to cathlab (immediate transfer) and group II (n=219) included patients transferred by referring hospitals (staged transfer). The results of thrombolysis in myocardial infarction (TIMI) flow before and after PCI, ST-segment resolution (STSR), troponin T level, and myocardial blush grade were analyzed in relation to delay to intervention.

RESULTS

The delay between pharmacologic pretreatment and angiography was two times longer in cases of staged transfer (80 vs. 47.5 min; P<0.0001). Despite the longer delay, higher rates of preangiography total STSR (26.4 vs. 15.5%; P=0.039) and initial TIMI flow 3 (20.1 vs. 11.1%; P=0.059) were observed in those patients. Differences in the rate of total STSR (70.3 vs. 66.7%; P=0.52), TIMI flow 3 (91.3 vs. 88.9%; P=0.33), and myocardial blush grade (60.7 vs. 63.3%; P=0.66) were no longer observed after PCI. Similarly, the peak troponin T level was also comparable (3.6 vs. 3.9 ng/ml; P=0.74).

CONCLUSION

Pretreatment with a combination of antiplatelet and antithrombotic agents may improve myocardial perfusion and compromise longer delay to a mechanical intervention.

WITHDRAWN: Preoperative statin therapy for patients undergoing cardiac surgery

This review has been withdrawn as authors are unable to complete the updating process.

The editorial group responsible for this previously published document have withdrawn it from publication.

Antiplatelet Therapy in Percutaneous Coronary Intervention

Platelets play a key role in mediating stent thrombosis, which is the major cause of ischemic events immediately after percutaneous coronary intervention (PCI). Antiplatelet therapy is therefore the cornerstone of antithrombotic therapy after PCI. However, the use of antiplatelet agents increases bleeding risk, with more potent antiplatelet agents further increasing bleeding risk. In the past 5 years, potent and fast-acting P2Y12 inhibitors have augmented the antiplatelet armamentarium available to interventional cardiologists. This article reviews the preclinical and clinical data surrounding these new agents, and discusses the significant questions and controversies that still exist regarding the optimal antiplatelet strategy.

Safety and Efficacy of Switching From Clopidogrel to Prasugrel in Patients Undergoing Percutaneous Coronary Intervention: A Study-level Meta-analysis From 15 Studies

BACKGROUND

There is poor evidence on clinical outcome of switching from clopidogrel to prasugrel in patients undergoing percutaneous coronary intervention.

OBJECTIVES

Data on the topic are limited and we performed a study-level meta-analysis to assess safety and efficacy of such strategy.

METHODS

A total of 15 studies and 3974 patients were included. The following comparisons were performed: prasugrel switching versus prasugrel only therapy; and prasugrel switching versus clopidogrel only therapy. Outcome measures were overall bleeding, major bleeding, and major adverse cardiac events (MACE).

RESULTS

There was no statistically significant increased bleeding risk in the prasugrel switching versus prasugrel only group [overall bleeding: OR 1.07, 95% confidence interval (CI), 0.69-1.66; P = 0.77; major bleeding: OR 0.69, 95% CI, 0.32-1.49; P = 0.34]; MACE rates were also comparable. Incidence of safety end points was similar in the prasugrel switching and clopidogrel only groups (overall bleeding: OR 1.27, 95% CI, 0.75-2.15; P = 0.37; major bleeding: OR 0.70, 95% CI, 0.29-1.68; P = 0.42); occurrence of MACE was 3.8% in the prasugrel switching versus 8.3% in the clopidogrel only group (P = 0.23). No statistically significant difference in the safety outcomes was present stratifying by clinical presentation.

CONCLUSIONS

Switching from clopidogrel to prasugrel does not increase bleeding complications during follow-up of patients undergoing percutaneous coronary intervention; however, the strength of the data is not sufficient to make definitive clinical recommendations.

Oral Antiplatelet Therapy in Coronary Disease

Ischemic heart disease is the major isolated cause of death worldwide, responsible for 7,249,000 deaths in 2008, 12.7% of deaths from any causes. The inhibition of platelet activation and aggregation is an important therapeutic target. Cyclooxygenase inhibitors and thienopyridines are currently the 2 most used pharmacological classes, but novel antiplatelet agents have currently an important role. The most recent thienopyridine, prasugrel, allows an irreversible inhibition of the P2Y12 platelet receptor associated to a faster and more consistent onset of action rather the previous antiplatelet agents of the same class. Cyclopentyl-triazolo-pyrimidines, a newer pharmacological class from which ticagrelor is an example, also act at the P2Y12 platelet receptor, and like prasugrel, ticagrelor inhibits platelet aggregation in a fast and consistent manner, however, in a reversible way. This article aims to conduct a review on the literature about the most recent information and guidelines on oral antiplatelet agents available for the management of coronary disease.

Type 2 Diabetes and ADP Receptor Blocker Therapy

Type 2 diabetes (T2D) is associated with several abnormalities in haemostasis predisposing to thrombosis. Moreover, T2D was recently connected with a failure in antiplatelet response to clopidogrel, the most commonly used ADP receptor blocker in clinical practice. Clopidogrel high on-treatment platelet reactivity (HTPR) was repeatedly associated with the risk of ischemic adverse events. Patients with T2D show significantly higher residual platelet reactivity on ADP receptor blocker therapy and are more frequently represented in the group of patients with HTPR. This paper reviews the current knowledge about possible interactions between T2D and ADP receptor blocker therapy.

On-treatment platelet reactivity: State of the art and perspectives

High on-clopidogrel platelet reactivity (HcPR) during dual-antiplatelet therapy is a marker of vascular risk, in particular stent thrombosis, in patients with acute coronary syndromes (ACS). Genetic determinants (CYP2C19*2 polymorphism), advanced age, female gender, diabetes and reduced ventricular function are related to a higher risk to develop HcPR. In addition, inflammation and increased platelet turnover, as revealed by the elevated percentage of reticulated platelets in patients' blood, that characterize the acute phase of acute coronary syndromes, are associated with HcPR. To overcome the limitation of clopidogrel, new antiplatelet agents (prasugrel and ticagrelor) were developed and the demonstration of their superiority over clopidogrel was obtained in the two randomized trials, TRITON TIMI 38 and PLATO. Emerging evidence is accumulating on the role of high-on aspirin platelet reactivity (HaPR), especially in the clinical context of diabetes. Finally, the presence of new, potent antiplatelet drugs has shifted the focus from thrombotic to bleeding risk. Recent data document that low on-treatment platelet reactivity (LPR) is associated with a significantly higher bleeding risk. Due to the current possibility to choose between multiple antiplatelet strategies, the future perspective is to include in the management of ACS, in addition to clinical data and classical risk factors, the definition of platelet function during treatment in order to set a tailored therapy.

Ticagrelor: a safe and effective approach for overcoming clopidogrel resistance in patients with stent thrombosis?

Stent thrombosis is a morbid complication following percutaneous coronary intervention (PCI). Dual antiplatelet therapy significantly reduces stent thrombosis risk. However, the antiplatelet response to clopidogrel - the most frequently used ADP receptor antagonist in post-PCI patients - varies among individuals. High on-treatment platelet reactivity was repeatedly associated with the risk of stent thrombosis. Ticagrelor is a novel ADP receptor blocker that has shown greater, more rapid and more consistent platelet inhibition than clopidogrel. This agent offers a unique mechanism of action, no relevant pharmacological interactions, consistent platelet inhibition, and a good safety profile. This article reviews the prospective use of ticagrelor in the treatment of stent thrombosis in acute coronary syndrome patients undergoing PCI of culprit coronary lesion.

Preoperative statin therapy for patients undergoing cardiac surgery

BACKGROUND

Patients referred to cardiac surgery for cardiovascular disease are at significant risk for the development of major postoperative adverse events despite significant advances in surgical techniques and perioperative care. Statins (5-hydroxy-3-methylglutaryl-co-enzyme A (HMG-CoA) reductase inhibitors) have gained a pivotal role in the primary and secondary prevention of coronary artery disease and are thought to improve perioperative outcomes in patients undergoing cardiac surgery. This review is an updated version of a review that was first published in 2012.

OBJECTIVES

To determine the effectiveness of preoperative statin therapy in patients undergoing cardiac surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11), MEDLINE (1950 to November 2013 Week 3), EMBASE (1980 to 3 December 2013 (Week 48)) and the metaRegister of Controlled Trials. Additionally, we searched ongoing trials through the National Research Register, the ClinicalTrials.gov registry and grey literature. We screened online conference indices from relevant scientific meetings (2006 to 2014) to look for eligible trials. We applied no language restrictions.

SELECTION CRITERIA

All randomised controlled trials comparing any statin treatment before cardiac surgery, for any given duration and dose, versus no preoperative statin therapy (standard of care) or placebo.

DATA COLLECTION AND ANALYSIS

Two review authors evaluated trial quality and extracted data from titles and abstracts identified by electronic database searches according to predefined criteria. Accordingly, we retrieved full-text articles of potentially relevant studies that met the inclusion criteria to assess definitive eligibility for inclusion. We reported effect measures as odds ratios (ORs) or weighted mean differences (WMDs) with 95% confidence intervals (95% CIs).

MAIN RESULTS

We identified 17 randomised controlled studies including a total of 2138 participants undergoing on-pump or off-pump cardiac surgical procedures, and added to this review six studies with 1154 additional participants. Pooled analysis showed that statin treatment before surgery reduced the incidence of postoperative atrial fibrillation (AF) (OR 0.54, 95% CI 0.43 to 0.67; P value < 0.01; 12 studies, 1765 participants) but failed to influence short-term mortality (OR 1.80, 95% CI 0.38 to 8.54; P value = 0.46; two studies, 300 participants) or postoperative stroke (OR 0.70, 95% CI 0.14 to 3.63; P value = 0.67; two studies, 264 participants). In addition, statin therapy was associated with a shorter stay for patients on the intensive care unit (ICU) (WMD -3.19 hours, 95% CI -5.41 to -0.98; nine studies, 721 participants) and in the hospital (WMD -0.48 days, 95% CI -0.78 to -0.19; 11 studies, 1137 participants) when significant heterogeneity was observed. Results showed no reduction in myocardial infarction (OR 0.48, 95% CI 0.21 to 1.13; seven studies, 901 participants) or renal failure (OR 0.57, 95% CI 0.30 to 1.10; five studies, 467 participants) and were not affected by subgroup analysis. Trials investigating this safety endpoint reported no major or minor perioperative side effects of statins.

AUTHORS' CONCLUSIONS

Preoperative statin therapy reduces the odds of postoperative atrial fibrillation (AF) and shortens the patient's stay on the ICU and in the hospital. Statin pretreatment had no influence on perioperative mortality, stroke, myocardial infarction or renal failure, but only two of all included studies assessed mortality. As analysed studies included mainly individuals undergoing myocardial revascularisation, results cannot be extrapolated to patients undergoing other cardiac procedures such as heart valve or aortic surgery.

Ticagrelor, prasugrel, or clopidogrel in ST-segment elevation myocardial infarction: which one to choose?

INTRODUCTION

Clopidogrel, prasugrel, and ticagrelor are the currently available oral P2Y12 inhibitors for the treatment of ST-segment elevation myocardial infarction (STEMI), in association with aspirin. These agents bind the P2Y12 platelet receptor and thus inhibit platelet aggregation. Large randomized clinical trials have provided efficacy and safety data on P2Y12 inhibitors in STEMI patients.

AREAS COVERED

This review focuses on key pharmacologic and clinical aspects of clopidogrel, prasugrel, and ticagrelor, highlighting their differences. Results from the main clinical trials are discussed, as well as the current STEMI guideline recommendations, to help inform agent selection for patients presenting with STEMI.

EXPERT OPINION

Clinical trials studying newer P2Y12 inhibitors with increased potency have shown further reduction of cardiovascular events compared with clopidogrel, therefore suggesting the use of ticagrelor or prasugrel as a first-line agent for STEMI treatment. There are still clinical situations - such as fibrinolysis, high risk of bleeding, use of oral anticoagulant, and financial hurdles - in which clopidogrel maintains a role in the treatment of STEMI.

Pharmacology of antithrombotic drugs: an assessment of oral antiplatelet and anticoagulant treatments

Antithrombotic drugs, which include antiplatelet and anticoagulant therapies, prevent and treat many cardiovascular disorders and, as such, are some of the most commonly prescribed drugs worldwide. The first drugs designed to inhibit platelets or coagulation factors, such as the antiplatelet clopidogrel and the anticoagulant warfarin, significantly reduced the risk of thrombotic events at the cost of increased bleeding in patients. However, both clopidogrel and warfarin have some pharmacological limitations including interpatient variability in antithrombotic effects in part due to the metabolism, interactions (eg, drug, environment, and genetic), or targets of the drugs. Increased knowledge of the pharmacology of antithrombotic drugs and the mechanisms underlying thrombosis has led to the development of newer drugs with faster onset of action, fewer interactions, and less interpatient variability in their antithrombotic effects than previous antithrombotic drugs. Treatment options now include the next-generation antiplatelet drugs prasugrel and ticagrelor, and, in terms of anticoagulants, inhibitors that directly target factor IIa (dabigatran) or Xa (rivaroxaban, apixaban, edoxaban) are available. In this Series paper we review the pharmacological properties of these most commonly used oral antithrombotic drugs, and explore the development of antiplatelet and anticoagulant therapies.

P2Y12 antagonists in non-ST-segment elevation acute coronary syndromes: latest evidence and optimal use

Dual antiplatelet therapy (DAPT), which includes the combination of aspirin and a P2Y12 platelet receptor inhibitor, is a well-established antiplatelet regimen in the treatment of patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Three P2Y12 inhibitor options (clopidogrel, prasugrel and ticagrelor) are currently available, all having different efficacy and safety profiles along with contrasting contraindications, special warnings and precautions for use. This review compares and contrasts the unique P2Y12 antagonists in the NSTE-ACS setting, covering the latest evidence and their optimal use.