Comparative Safety and Effectiveness of Loading Doses of P2Y12 Inhibitors in Patients Undergoing Elective PCI: a Network Meta-analysis.

PURPOSE: Effective platelet inhibition prior to elective percutaneous coronary intervention (PCI) reduces the risk of ischemic complications. Newer P2Y12 inhibitors are preferred agents over clopidogrel for patients presenting with the acute coronary syndrome. However, the comparative efficacy and safety of them over clopidogrel in elective PCI is unclear. We performed a network meta-analysis to compare the safety and efficacy of loading strategies of P2Y12 inhibitors in patients undergoing elective PCI. METHODS: We conducted a systematic review of randomized controlled trials (RCT) up to June 2021 to compare the safety and effectiveness of different loading strategies of P2Y12 inhibitors before elective PCI. The endpoints of interest were overall mortality, rates of myocardial infarction (MI), stroke, revascularization, and major bleeding. Random effects model using the frequentist approach was used to perform a network meta-analysis using R software. RESULTS: Five trials with a total of 5194 patients were included in our analysis. For ischemic outcomes, including MI, stroke, and revascularization, prasugrel had the most favorable trend. However, clopidogrel had the highest probability of being most effective for major bleeding and all-cause mortality. None of these trends was statistically significant due to lack of power for each outcome. CONCLUSION: Although prasugrel and ticagrelor are known as more potent antiplatelet agents, their effects in preventing MI and stroke are marginal and do not translate into improved overall mortality and bleeding compared with clopidogrel.

Safety and Cumulative Incidence of Major Cardiovascular Events with Ticagrelor in Taiwanese Patients with Non-ST-Segment Elevation Myocardial Infarction: A 12-Month, Prospective, Phase IV, Multicenter, Single-Arm Study.

BACKGROUND: Ticagrelor, an oral, direct-acting, and reversible P2Y12 receptor antagonist, inhibits platelet activation and aggregation. This phase IV, single-arm study analyzed the safety and tolerability of ticagrelor in Taiwanese patients with non-ST-segment elevation myocardial infarction (NSTEMI) during 1 year of follow-up. METHODS: Patients aged ≥ 20 years with an index event of NSTEMI received ticagrelor (180 mg loading and 90 mg doses twice daily thereafter) plus low-dose aspirin (100 mg/day) for up to 1 year. Safety was evaluated according to adverse events (AEs), serious AEs (SAEs), and PLATO-defined bleeding events. The cumulative incidence of major cardiovascular (CV) events including CV death, myocardial infarction, and stroke was also evaluated. RESULTS: The safety population included 108 patients across 13 centers in Taiwan. During treatment, 32 (29.6%) patients had ≥ one PLATO-defined bleeding event. Major bleeding events occurred in seven (6.5%) patients with a Kaplan-Meier (KM) estimated event risk [95% confidence interval (CI)] of 7.1% (3.4%-14.4%), including life-threatening bleeding [four (3.7%) patients] and other major bleeding [three (2.8%) patients]. No PLATO-defined fatal bleeding was observed. SAEs were reported in 23 (21.3%) patients. Six (5.6%) patients experienced major CV events during the 1-year follow-up period, with a KM-estimated event risk (95% CI) of 5.6% (2.6%-12.0%). CONCLUSIONS: Ticagrelor for up to 1 year was associated with a low rate of major bleeding events and a low incidence of major CV events in Taiwanese patients with NSTEMI. The overall safety of ticagrelor was in accordance with the known safety profile of ticagrelor.

Preprocedural P2Y12 inhibition and decrease in platelet count following transcatheter aortic valve replacement.

BACKGROUND: Thrombocytopenia after transcatheter aortic valve replacement (TAVR) is associated with adverse clinical outcomes. Whether preprocedural P2Y12 inhibition prevents postprocedural thrombocytopenia is uncertain. METHODS: This retrospective analysis identified consecutive patients (n = 266) undergoing TAVR between November 2016 and July 2017. Preprocedure clopidogrel load ≥300 mg or maintenance P2Y12 inhibitor therapy defined preprocedural P2Y12 inhibition. Patients who did not consent for the registry (n = 8), with baseline severe thrombocytopenia (<90 × 103 platelets/µL; n = 14), or without baseline platelet count (n = 4) were excluded. The primary outcome was proportion of patients who developed >20% decrease in platelet count from baseline to day 1 post-TAVR. RESULTS: Patients with (n = 134) versus without (n = 106) preprocedural P2Y12 inhibition had no differences in platelet count at baseline. Patients with preprocedural P2Y12 inhibition had a significantly lower proportion of the primary outcome (34.3% vs. 57.5%, p = .001) and a lower absolute decrease in platelet count (32.8 × 103 vs. 45.8 × 103 platelet/µL, p = .01). Of patients without baseline thrombocytopenia (n = 198), a numerically lower rate of patients with versus without preprocedural P2Y12 inhibition developed thrombocytopenia on day 1 post-TAVR (25.5% vs. 36.4%, p = .1). CONCLUSION: Patients who received preprocedural P2Y12 inhibition prior to TAVR were less likely to demonstrate a decrease in platelet count after TAVR. Prospective studies to further understand the clinical implication of these findings are warranted.

Ischaemic risk and efficacy of ticagrelor in relation to time from P2Y12 inhibitor withdrawal in patients with prior myocardial infarction: insights from PEGASUS-TIMI 54.

AIMS: Ticagrelor reduced major adverse cardiovascular event (MACE) by 15-16% in patients with prior myocardial infarction (MI) in PEGASUS-TIMI 54. We hypothesized that patients who recently discontinued P2Y12 inhibition, even years after MI, may be at particular risk of MACE and may derive particular benefit from continuation or reinitiation of therapy. METHODS AND RESULTS: Patients in PEGASUS-TIMI 54 were categorized by time from last P2Y12 inhibitor (days: ≤30, >30-360, >360). The risk of MACE and the efficacy of ticagrelor were compared across categories. In the placebo arm, patients who more recently stopped P2Y12 inhibitor therapy had a greater number of risk factors but still had a higher risk of MACE after multivariable adjustment [≤30 days, hazard ratio (HR)adj 1.47, 95% confidence interval (CI) 1.12-1.93, P = 0.0051; 30 days-1 year, HRadj 1.28, 95% CI 0.98-1.67, P = 0.073] compared with those who stopped >1 year prior (P-trend = 0.0097). The benefit of ticagrelor depended on the time from last dose, with HRs (95% CI) for ticagrelor (pooled doses) vs. placebo of 0.73 (0.61-0.87), 0.86 (0.71-1.04), and 1.01 (0.80-1.27), respectively, by category (P-trend for interaction < 0.001). The benefit in those ≤30 days of stopping was similar regardless of time from MI (<2 years, HR 0.73, 95% CI 0.60-0.89 vs. ≥2 years, HR 0.71, 95% CI 0.50-1.00). CONCLUSION: The benefit of ticagrelor for long-term secondary prevention in patients with prior MI and at least one additional risk factor appeared more marked in patients continuing on or re-starting after only a brief interruption of P2Y12 inhibition, when compared with patients who had proved themselves stable more than 2 years from their MI and off P2Y12 inhibitor therapy for more than a year. The increase in bleeding events with ticagrelor was similar regardless of this time interval. For clinicians considering a strategy of prolonged P2Y12 inhibitor therapy in high-risk patients, these data suggest greater benefit in the continuation of such therapy without interruption after MI, rather than re-initiating such therapy in patients who have remained stable for an extended period. Future analyses may help to clarify further the profile of post-MI patients most likely to benefit from uninterrupted dual antiplatelet therapy. CLINICAL TRIAL REGISTRATION INFORMATION: http://www.clinicaltrials.gov NCT01225562.

Migraine Headache and Patent Foramen Ovale: Observational Studies, the Randomized Clinical Trials, and the GORE RELIEF Clinical Study.

The pathophysiology of migraine remains poorly understood. Like most migraine preventive therapies, patent foramen ovale (PFO) closure was never intended for the treatment of migraine. After closure of PFO for other reasons, migraine symptom reduction/elimination was noted in some patients. Subsequent small trials failed to prove its benefit. There is significant evidence suggesting a platelet-mediated mechanism linking migraines to PFO. The GORE RELIEF Clinical Study is a randomized, blinded, placebo- and sham-controlled trial, currently enrolling. The study design is meant to optimize patient selection using thienopyridine responsiveness as an inclusion criterion.

Clopidogrel vs Aspirin Monotherapy Beyond 1 Year After Percutaneous Coronary Intervention.

BACKGROUND: It remains unclear whether clopidogrel is better suited than aspirin as the long-term antiplatelet monotherapy following dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI). OBJECTIVES: This study compared clopidogrel monotherapy following 1 month of DAPT (clopidogrel group) with aspirin monotherapy following 12 months of DAPT (aspirin group) after PCI for 5 years. METHODS: STOPDAPT-2 (Short and Optimal Duration of Dual Antiplatelet Therapy 2) is a multicenter, open-label, adjudicator-blinded, randomized clinical trial conducted in Japan. Patients who underwent PCI with cobalt-chromium everolimus-eluting stents were randomized in a 1-to-1 fashion either to clopidogrel or aspirin groups. The primary endpoint was a composite of cardiovascular outcomes (cardiovascular death, myocardial infarction, stroke, or definite stent thrombosis) or major bleeding (TIMI major or minor bleeding). RESULTS: Among 3,005 study patients (age: 68.6 ± 10.7 years; women: 22.3%; acute coronary syndrome: 38.3%), 2,934 patients (97.6%) completed the 5-year follow-up (adherence to the study drugs at 395 days: 84.7% and 75.9%). The clopidogrel group compared with the aspirin group was noninferior but not superior for the primary endpoint (11.75% and 13.57%, respectively; HR: 0.85; 95% CI: 0.70-1.05; Pnoninferiority < 0.001; Psuperiority = 0.13), whereas it was superior for the cardiovascular outcomes (8.61% and 11.05%, respectively; HR: 0.77; 95% CI: 0.61-0.97; P = 0.03) and not superior for major bleeding (4.44% and 4.92%, respectively; HR: 0.89; 95% CI: 0.64-1.25; P = 0.51). By the 1-year landmark analysis, clopidogrel was numerically, but not significantly, superior to aspirin for cardiovascular events (6.79% and 8.68%, respectively; HR: 0.77; 95% CI: 0.59-1.01; P = 0.06) without difference in major bleeding (3.99% and 3.32%, respectively; HR: 1.23; 95% CI: 0.84-1.81; P = 0.31). CONCLUSIONS: Clopidogrel might be an attractive alternative to aspirin with a borderline ischemic benefit beyond 1 year after PCI.

Current and Future Insights for Optimizing Antithrombotic Therapy to Reduce the Burden of Cardiovascular Ischemic Events in Patients with Acute Coronary Syndrome.

The pharmacological treatment strategies for acute coronary syndrome (ACS) in recent years are constantly evolving to develop more potent antithrombotic agents, as reflected by the introduction of more novel P2Y12 receptor inhibitors and anticoagulants to reduce the ischemic risk among ACS patients. Despite the substantial improvements in the current antithrombotic regimen, a noticeable number of ACS patients continue to experience ischemic events. Providing effective ischemic risk reduction while balancing bleeding risk remains a clinical challenge. This updated review discusses the currently approved and widely used antithrombotic agents and explores newer antithrombotic treatment strategies under development for the initial phase of ACS.

P2Y12 inhibition in acute coronary syndromes treated with percutaneous intervention - Understanding the debate on Prasugrel or Ticagrelor.

After more than 10 years of routine clinical use, a debate about the preference of prasugrel over ticagrelor has been unveiled following publication of the ISAR-REACT 5 trial, an investigator-initiated trial directly comparing both substances as part of dual anti-platelet therapy following interventional treatment in patients with acute coronary syndromes (ACS). Both substances had been tested in trials, approved by authorities and subsequently recommended by guidelines according to the strategy applied in the respective approval trial. This resulted in prasugrel tested in TRITON only be given after diagnostic coronary angiography in the absence of ST-segment elevations (NSTE-ACS) and ticagrelor tested in PLATO being administered even before diagnostic coronary angiography in all forms of acute coronary syndromes. Whichever way was safest and most efficient, had never been clarified before. ISAR-REACT 5 showed superior efficacy of prasugrel over ticagrelor in general, and of deferred administration of prasugrel over pre-treatment with ticagrelor in NSTE-ACS patients undergoing percutaneous coronary interventions. Subsequently, in 2020 the European guidelines for NSTE-ACS adopted both positions in recommending the respective preference. Afterwards, a confrontational debate erupted between those favouring the ISAR-REACT 5 results and their implementation in guidelines and others still preferring the generalized interpretation of the overall study results from PLATO. In this review, we reflect the history leading to trial design of TRITON and PLATO and the way this subsequently impacted on clinical practice and guideline recommendations.

P2Y12 Inhibition in Murine Myocarditis Results in Reduced Platelet Infiltration and Preserved Ejection Fraction.

Previous mouse studies have shown the increased presence of platelets in the myocardium during early stages of myocarditis and their selective detection by MRI. Here, we aimed to depict early myocarditis using molecular contrast-enhanced ultrasound of activated platelets, and to evaluate the impact of a P2Y12 receptor platelet inhibition. Experimental autoimmune myocarditis was induced in BALB/c mice by subcutaneous injection of porcine cardiac myosin and complete Freund adjuvant (CFA). Activated platelets were targeted with microbubbles (MB) coupled to a single-chain antibody that binds to the "ligand-induced binding sites" of the GPIIb/IIIa-receptor (=LIBS-MB). Alongside myocarditis induction, a group of mice received a daily dose of 100 g prasugrel for 1 month. Mice injected with myosin and CFA had a significantly deteriorated ejection fraction and histological inflammation on day 28 compared to mice only injected with myosin. Platelets infiltrated the myocardium before reduction in ejection fraction could be detected by echocardiography. No selective binding of the LIBS-MB contrast agent could be detected by either ultrasound or histology. Prasugrel therapy preserved ejection fraction and significantly reduced platelet aggregates in the myocardium compared to mice without prasugrel therapy. Therefore, P2Y12 inhibition could be a promising early therapeutic target in myocarditis, requiring further investigation.

Antithrombotic Strategy for Patients with Acute Coronary Syndrome: A Perspective from East Asia.

Dual antiplatelet therapy (DAPT) after percutaneous coronary intervention has become the standard of care, particularly in patients with acute coronary syndrome (ACS). Current clinical guidelines recommend novel P2Y12 inhibitors (e.g., prasugrel or ticagrelor) in addition to aspirin based on the results of representative randomized controlled trials conducted predominantly in Western countries. These agents were superior to clopidogrel in reducing the composite ischemic events, with a trade-off of the increased bleeding events. However, multiple differences exist between East Asian and Western patients, especially with respect to their physique, thrombogenicity, hemorrhagic diathesis, and on-treatment platelet reactivity. Recent studies from East Asian countries (e.g., Japan or South Korea) have consistently demonstrated that use of novel P2Y12 inhibitors is associated with a higher risk of bleeding events than use of clopidogrel, despite borderline statistical difference in the incidence of composite ischemic events. Additionally, multiple studies have shown that the optimal duration of DAPT may be shorter in East Asian than Western patients. This review summarizes clinical studies of antithrombotic strategies in East Asian patients with ACS. Understanding these differences in antithrombotic strategies including DAPT and their impacts on clinical outcomes will aid in selection of the optimal tailored antithrombotic therapy for patients with ACS.

Optimal Antithrombotic Treatment of Patients with Atrial Fibrillation Early after an Acute Coronary Syndrome-Triple Therapy, Dual Antithrombotic Therapy with an Anticoagulant Or, Rather, Temporary Dual Antiplatelet Therapy?

The combination of atrial fibrillation (AF) and acute coronary syndrome (ACS) is a complex situation in which a three-dimensional risk-cardioembolic, coronary, and hemorrhagic-has to be carefully managed. Triple antithrombotic therapy (TAT) is burdened with a high risk of serious bleeding, while dual antithrombotic therapy with an anticoagulant (DAT) likely provides only suboptimal coronary protection early after stent implantation. Moreover, TAT precludes the advantages provided by the use of the latest and more potent P2Y12 inhibitors in ACS patients. Here, we aimed to simulate and compare the expected coronary, cardioembolic, and hemorrhagic outcomes offered by DAT, TAT, or modern dual antiplatelet therapy (DAPT) with aspirin plus one of the latest P2Y12 inhibitors in AF patients early after an ACS. The comparison of numbers needed to treat to prevent major adverse events with the various antithrombotic regimens suggests that AF-ACS patients at high ischemic and hemorrhagic risk and at moderately low embolic risk (CHA2DS2VASc score 2-4) might safely withhold anticoagulation after revascularization for one month taking advantage of a modern DAPT, with a favorable risk-to-benefit ratio. In conclusion, this strategy, not sufficiently addressed in recent European and North American guidelines or consensus documents, adds to the spectrum of treatment options in these difficult patients; it might be the best choice in a substantial number of patients; and should be prospectively tested in a randomized controlled trial.

Acute Coronary Syndrome, Antiplatelet Therapy, and Bleeding: A Clinical Perspective.

Inhibition of platelet function by means of dual antiplatelet therapy (DAPT) is the cornerstone of treatment of acute coronary syndrome (ACS). While preventing ischemic recurrences, inhibition of platelet function is clearly associated with an increased bleeding risk, a feared complication that may lead to significant morbidity and mortality. Since bleeding risk management is intrinsically associated with therapeutic adjustments undertaken during the whole clinical history of patients with acute coronary syndrome, single decisions taken from the very first day to years of follow-up might be decisive. This review aims at providing a clinically oriented, patient-tailored approach in reducing the risk and manage bleeding complications in ACS patients treated with DAPT. The steps in clinical decision making from the day of ACS to follow-up are analyzed. New treatment strategies to enhance the safety of DAPT are also described.

Efficacy and Safety of Ticagrelor Over Time in Patients With Prior MI in PEGASUS-TIMI 54.

BACKGROUND: Ticagrelor reduces ischemic risk in patients with prior myocardial infarction (MI). It remains unclear whether ischemic risk and the benefits of prolonged P2Y12 inhibition in this population remain consistent over time. OBJECTIVES: The study sought to investigate the pattern of ischemic risk over time and whether the efficacy and safety of ticagrelor were similar early and late after randomization. METHODS: The PEGASUS-TIMI (Prevention of Cardiovascular Events in Patients with Prior Heart Attack Using Ticagrelor Compared to Placebo on a Background of Aspirin-Thrombolysis In Myocardial Infarction) 54 trial randomized patients with prior MI (median 1.7 years prior) to ticagrelor 90 mg, ticagrelor 60 mg, or placebo on a background of aspirin. The rates of cardiovascular (CV) death, MI, and stroke as well as TIMI major bleeding were analyzed at yearly landmarks (years 1, 2, and 3). RESULTS: A total of 21,162 patients were randomized and followed for 33 months (median), with 28% of patients ≥5 years from MI at trial conclusion. The risk of CV death, MI, or stroke in the placebo arm remained roughly constant over the trial at an ∼3% annualized rate. The benefit of ticagrelor 60 mg was consistent at each subsequent landmark (year 1 hazard ratio [HR]: 0.82; 95% confidence interval [CI]: 0.67 to 0.99; year 2 HR: 0.90; 95% CI: 0.74 to 1.11; and year 3 HR: 0.79; 95% CI: 0.62 to 1.00). TIMI major bleeding was increased with ticagrelor 60 mg at each landmark, but with the greatest hazard in the first year (year 1 HR: 3.22; year 2 HR: 2.07; year 3 HR: 1.65). CONCLUSIONS: Patients with a history of MI remain at persistent high risk for CVD, MI, and stroke as late as 5 years after MI. The efficacy of low-dose ticagrelor is consistent over time with a trend toward less excess bleeding. (Prevention of Cardiovascular Events in Patients with Prior Heart Attack Using Ticagrelor Compared to Placebo on a Background of Aspirin [PEGASUS]; NCT01225562).

Comparison of a new ELISA-based with the flow cytometric assay for vasodilator-associated stimulated phosphoprotein phosphorylation to assess P2Y12 -inhibition after ticagrelor intake.

BACKGROUND: Ticagrelor is a P2Y12 receptor antagonist, with superior effects but also ensuing enhanced bleeding risk as compared to clopidogrel. Determination of platelet inhibition may be useful to confirm efficient platelet inhibition on an individual patient level and to identify patients at risk for bleeding. The vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation assay specifically measures platelet P2Y12 inhibition, but has so far required individual sample processing. A new ELISA-based VASP assay has been developed, which allows batch analysis after initial platelet activation. Because of the reversible binding of ticagrelor it is unclear if the ELISA and flow cytometric assays provide comparable results; several washing steps of the ELISA may potentially result in false low results through dilution. METHODS: We hypothesized that the conventional and new methods may be comparable when ticagrelor is used. We pair-wise compared the platelet reactivity index (PRI) between assays in a prospective clinical trial. Six healthy volunteers received a single 180 mg loading dose of ticagrelor. RESULTS: PRI-values of the two methods correlated well (r = 0.97, P < 0.001). Ticagrelor rapidly decreased PRI values on average after 50 min, but nadir levels 2-6 h after ticagrelor intake were 15% higher when PRI% was measured with the flow cytometric method. Bland-Altman analysis showed that the flow cytometric assay measured markedly higher PRI levels than the new ELISA-based technique (mean difference 13%). CONCLUSIONS: The new ELISA-based VASP assay offers an alternative to the currently used flow cytometric method, but measures lower PRI levels, particularly when PRI falls below 20% after ticagrelor intake.

Comparison of a new ELISA-based with the flow cytometric assay for vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation to assess P2Y12 -inhibition after ticagrelor intake.

BACKGROUND: Ticagrelor is a P2Y12 receptor antagonist, with superior effects but also ensuing enhanced bleeding risk as compared to clopidogrel. Determination of platelet inhibition may be useful to confirm efficient platelet inhibition on an individual patient level and to identify patients at risk for bleeding. The vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation assay specifically measures platelet P2Y12 inhibition, but has so far required individual sample processing. A new ELISA-based VASP assay has been developed which allows batch analysis after initial platelet activation. Due to the reversible binding of ticagrelor it is unclear if the ELISA and flow cytometric assays provide comparable results; several washing steps of the ELISA may potentially result in false low results through dilution. METHODS: We hypothesized that the conventional and new methods may be comparable when ticagrelor is used. We pair-wise compared the platelet reactivity index (PRI) between assays in a prospective clinical trial. Six healthy volunteers received a single 180 mg loading dose of ticagrelor. RESULTS: PRI-values of the two methods correlated well (r=0.97, p<0.001). Ticagrelor rapidly decreased PRI values on average after 50 minutes, but nadir levels 2-6 hours after ticagrelor intake were 15% higher when PRI% was measured with the flow cytometric method. Bland-Altman analysis showed that the flow cytometric assay measured markedly higher PRI levels than the new ELISA-based technique (mean difference 13%). CONCLUSIONS: The new ELISA-based VASP assay offers an alternative to the currently used flow cytometric method, but measures lower PRI levels, particularly when PRI falls below 20% after ticagrelor intake. © 2013 Clinical Cytometry Society.