Impaired bioavailability and antiplatelet effect of high-dose clopidogrel in patients after cardiopulmonary resuscitation (CPR)

Strategies to optimize initial P2Y12 inhibitor therapy in STEMI patients

INTRODUCTION

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is the standard of care for patients who undergo percutaneous coronary intervention (PCI) for ST elevation myocardial infarction (STEMI). Though this regimen reduces rates of ischemic events in patients with STEMI, the optimal strategy for P2Y12 administration in STEMI patients is still evolving.

PURPOSE

The purpose of this review is to summarize current evidence on optimal use of ticagrelor and prasugrel in the acute phase of STEMI.

SUMMARY

Due to high platelet activity in the acute setting of STEMI and PCI, adequate and rapid platelet inhibition is important. Strategies of increased ticagrelor/prasugrel loading dose or earlier administration in STEMI have not been successful in closing this platelet inhibition gap. Potential strategies for improving ticagrelor/prasugrel use early in STEMI include bridging with intravenous antiplatelet agents or crushed or chewed administration.

CONCLUSION

Oral ticagrelor/prasugrel given before or immediately after STEMI PCI is usually sufficient to prevent thrombotic complications. When faster platelet inhibition is desired, or oral administration is compromised by inability to swallow tablets, crushing/chewing ticagrelor/prasugrel tablets is an alternative to intravenous P2Y12 inhibitor therapy.

Current and Future Roles of Glycoprotein IIb-IIIa Inhibitors in Primary Angioplasty for ST-Segment Elevation Myocardial Infarction

Acute myocardial infarction still represents the major cause of mortality in high-income countries. Therefore, considerable efforts have been focused on the treatment of myocardial infarctions in the acute and long-term phase, with special attention being paid to reperfusion strategies and adjunctive antithrombotic therapies. In fact, despite the successful mechanical recanalization of the epicardial conduit, a substantial percentage of patients still experience poor myocardial reperfusion or acute/subacute in-stent thrombosis. Due the delayed onset of action of currently available oral antiplatelet therapies, glycoprotein (GP) IIb-IIIa inhibitors could be expected to improve clinical outcomes, especially when administrated in the early phase of the infarction, due to the larger platelet composition of fresh thrombi, the dynamic nature of early thrombi, and the larger amount of viable myocardium existing in the early, as compared to a delayed, phase. Considerable evidence has accumulated regarding the benefits from GP IIb-IIIa inhibitors on mortality, especially among high-risk patients and when administered as an upstream strategy. Therefore, based on currently available data, GP IIb-IIIa inhibitors can be considered when the drug can be administered within the first 3 h of symptom onset and among high-risk patients (e.g., those with advanced Killip class or an anterior myocardial infarction). Even though it is not universally accepted, in our opinion, this strategy should be implemented in a pre-hospital setting (in an ambulance) or as soon as possible when arriving at the hospital (at the Emergency Room or Coronary Care Unit, irrespective of whether they are in spoke or hub hospitals). A new, second-generation GP IIb-IIIa inhibitor (zalunfiban) appears to be highly suitable as a pre-hospital pharmacological facilitation strategy at the time of first medical contact due to its favourable features, including its simple subcutaneous administration, rapid onset of action (15 min), and limited time of action (with a half-life of ~1 h), which is likely to minimize the risk of bleeding. The ongoing CELEBRATE trial, including 2499 STEMI patients, may potentially provide compelling data to support the upstream treatment of STEMI patients undergoing mechanical reperfusion. In fact, although the current therapeutic target of increased rates of timely reperfusion has been achieved, the future goal in myocardial infarction treatment should be to achieve the most rapid reperfusion prior to primary percutaneous coronary intervention, thus further minimizing myocardial damage, or, in some cases, even preventing it completely, and improving survival.

Use of cangrelor in patients with acute coronary syndromes undergoing percutaneous coronary intervention: Study design and interim analysis of the ARCANGELO study

BACKGROUND

The itAlian pRospective Study on CANGrELOr (ARCANGELO) was aimed to assess the safety of using cangrelor during percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS) in the daily practice.

HYPOTHESIS

The safety of cangrelor after the transition to oral P2Y12 inhibitors was evaluated as the incidence of bleeding outcomes in the 30 days following PCI according to postauthorization safety study guidelines.

METHODS

Adults with ACS who were treated with cangrelor in one of the 28 centers involved in the study. Patients who consented to participate were followed in the 30 days following their PCI. Bleedings (Bleeding Academic Research Consortium [BARC] classification), major adverse cardiac events (MACEs), and adverse events were recorded. The interim results at two-thirds of the enrollment period are presented.

RESULTS

A total of 17 bleedings were observed in the 320 patients who completed the study at this stage. All bleedings were classified as BARC Type 1-2, except for one case of Type 3a (vessel puncture site hematoma). Four patients experienced MACEs (2 acute myocardial infarctions, 1 sudden cardiac death, 1 noncardiovascular death due to respiratory distress, and multiorgan failure). None of the bleedings was rated as related to cangrelor.

CONCLUSIONS

The interim results of the ARCANGELO study provide a preliminary confirmation that the use of cangrelor on patients with ACS undergoing PCI is not associated with severe bleedings.

Newer P2Y12 Inhibitors vs Clopidogrel in Acute Myocardial Infarction With Cardiac Arrest or Cardiogenic Shock: A Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the outcomes, safety, and efficacy of dual antiplatelet therapy (DAPT) with newer P2Y₁₂ inhibitors compared with clopidogrel in patients with acute myocardial infarction (AMI) complicated by cardiac arrest (CA) or cardiogenic shock (CS).

PATIENTS AND METHODS

MEDLINE, EMBASE, and the Cochrane Library were queried systematically from inception to January 2021 for comparative studies of adults (≥18 years) with AMI-CA/CS receiving DAPT with newer P2Y₁₂ inhibitors as opposed to clopidogrel. We compared outcomes (30-day or in-hospital and 1-year all-cause mortality, major bleeding, and definite stent thrombosis) of newer P2Y₁₂ inhibitors and clopidogrel in patients with AMI-CA/CS.

RESULTS

Eight studies (1 randomized trial and 7 cohort studies) comprising 1100 patients (695 [63.2%] receiving clopidogrel and 405 [36.8%] receiving ticagrelor or prasugrel) were included. The population was mostly male (68.5%-86.7%). Risk of bias was low for these studies, with between-study heterogeneity and subgroup differences not statistically significant. Compared with the clopidogrel cohort, the newer P2Y₁₂ cohort had lower rates of early mortality (odds ratio [OR], 0.60; 95% CI, 0.45 to 0.81; P=.001) (7 studies) and 1-year mortality (OR, 0.51; 95% CI, 0.36 to 0.71; P<.001) (3 studies). We did not find a significant difference in major bleeding (OR, 1.21; 95% CI, 0.71 to 2.06; P=.48) (6 studies) or definite stent thrombosis (OR, 2.01; 95% CI, 0.63 to 6.45; P=.24) (7 studies).

CONCLUSION

In patients with AMI-CA/CS receiving DAPT, compared with clopidogrel, newer P2Y₁₂ inhibitors were associated with lower rates of early and 1-year mortality. Data on major bleeding and stent thrombosis were inconclusive.

Bioavailability of Orally Administered Drugs in Critically Ill Patients

Critically ill patients managed in the Intensive Care Unit (ICU) suffer from several pathophysiological alterations due to critical illness resulting in potential changes in the pharmacokinetics of drugs including systemic absorption. Nevertheless, these patients are still given some medications in unadjusted doses thereby putting the patients at a risk for therapy failure. The objective for this study was to summarize the available evidence regarding oral drug absorption in the ICU. A literature search of the databases MEDLINE, EMBASE, and PubMed was conducted on (February 24, 2020). Articles discussing the rate and/or extent of orally administered drugs in critically ill patients were included. A total of 58 studies were found: 17 interventional studies, 33 observational studies (30 prospective, 3 retrospective) and 8 case reports. A total of 43 articles reported altered drug absorption in critically ill patients suggesting the need for alternative measures to facilitate treatment success. The absorption of orally administered drugs may be altered in critically ill patients. Measures for altered drug absorption in critically ill patients were suggested such as holding tube feeding before and after medication administration, increasing doses of orally administrated drugs and using alternate routes of administration.

One-Year Outcome of Glycoprotein IIb/IIIa Inhibitor Therapy in Patients with Myocardial Infarction-Related Cardiogenic Shock

BACKGROUND

We aimed to evaluate the effect of intravenous glycoprotein IIb/IIIa receptor inhibitors (GPIs) on in-hospital survival and mortality during and at the 1-year follow-up in patients undergoing percutaneous coronary intervention (PCI) for myocardial infarction (MI) complicated by cardiogenic shock (CS), who were included in the Polish Registry of Acute Coronary Syndromes (PL-ACS).

METHODS

From 2003 to 2019, 466,566 MI patients were included in the PL-ACS registry. A total of 10,193 patients with CS received PCI on admission. Among them, GPIs were used in 3934 patients.

RESULTS

The patients treated with GPIs were younger, had lower systolic blood pressure on admission, required inotropes and intra-aortic balloon pump (IABP) support more frequently, and showed a lower efficacy of coronary angioplasty. In both groups, the same rates of in-hospital adverse events were observed. A lower mortality rate was reported in the group treated with GPIs 12 months after admission (54.9% vs. 57.9%, p = 0.002). Therapy with GPI was an independent factor reducing the risk of mortality in the 12-month follow-up.

CONCLUSIONS

The addition of GPIs to the standard pharmacotherapy combined with PCI in patients with MI and CS on admission reduced the risk of death in the 12-month follow-up period without increasing in-hospital adverse event rates.

The influence of acute coronary syndrome on levels of clopidogrel active metabolite and platelet inhibition in patients with and without CYP2C19*2(681 G>A), *3(636 G>A) and ABCB1(C3435C> T) gene polymorphisms

Introduction

Although ticagrelor and prasugrel remain the standard antiplatelet treatments in acute coronary syndrome (ACS), numerous patients still present with indications for clopidogrel use.

Aim

We aimed to assess the levels of clopidogrel active metabolite and to evaluate the effect of the drug on platelet inhibition in patients with ACS as compared with those with stable coronary disease. Patients were assessed for the presence of the most common genetic polymorphisms that reduce the absorption (ABCB1) and activation (CYP2C19*2 and CYP2C19*3) of clopidogrel to exclude the effect of genetic variability on drug concentrations and activity.

Material and methods

This single-center, open-label, prospective study included 199 patients hospitalized due to ST-segment elevation myocardial infarction (STEMI) or non-STEMI (NSTEMI) in Killip class I–III, who underwent percutaneous coronary intervention. The control group included 22 patients with stable coronary artery disease.

Results

The mean (SD) levels of active clopidogrel were 17.1 (12.3) ng/ml in controls and 16.4 (12.0) ng/ml in the whole study group (p < 0.68). No differences were noted in clopidogrel levels between patients with STEMI and NSTEMI (mean (SD), 17.6 (2.3) ng/ml and 15.1 (11.5) ng/ml; p < 0.45) or between STEMI and NSTEMI groups and controls (p < 0.38 and p < 0.61, respectively). No effect of ABCB1 or CYP2C19 polymorphism was observed in the study subgroups.

Conclusions

We concluded that ACS does not affect the levels of clopidogrel active metabolite or platelet inhibition in patients in Killip class I-III with or without CYP2C19 or ABCB1 gene polymorphisms.

Cangrelor Use in Routine Practice: A Two-Center Experience

Cangrelor is the first and only intravenous P2Y12-inhibitor and is indicated when (timely) administration of an oral P2Y12 inhibitor is not feasible in patients undergoing percutaneous coronary intervention (PCI). Our study evaluated the first years of cangrelor use in two Dutch tertiary care centers. Cangrelor-treated patients were identified using a data-mining algorithm. The cumulative incidences of all-cause death, myocardial infarction, definite stent thrombosis and major bleeding at 48 h and 30 days were assessed using Kaplan-Meier estimates. Predictors of 30-day mortality were identified using uni- and multivariable Cox regression models. Between March 2015 and April 2021, 146 patients (median age 63.7 years, 75.3% men) were treated with cangrelor. Cangrelor was primarily used in ST-segment elevation myocardial infarction (STEMI) patients (84.2%). Approximately half required cardiopulmonary resuscitation (54.8%) or mechanical ventilation (48.6%). The cumulative incidence of all-cause death was 11.0% and 25.3% at 48 h and 30 days, respectively. Two cases (1.7%) of definite stent thrombosis, both resulting in myocardial infarction, occurred within 30 days, but after 48 h. No other cases of recurrent myocardial infarction transpired within 30 days. Major bleeding occurred in 5.6% and 12.5% of patients within 48 h and 30 days, respectively. Cardiac arrest at presentation was an independent predictor of 30-day mortality (adjusted hazard ratio 5.20, 95%-CI: 2.10-12.9, p < 0.01). Conclusively, cangrelor was used almost exclusively in STEMI patients undergoing PCI. Even though cangrelor was used in high-risk patients, its use was associated with a low rate of stent thrombosis.

Feasibility and safety of cangrelor in patients with suboptimal P2Y12 inhibition undergoing percutaneous coronary intervention: rationale of the Dutch Cangrelor Registry

BACKGROUND

Despite the advances of potent oral P2Y12 inhibitors, their onset of action is delayed, which might have a negative impact on clinical outcome in patients undergoing percutaneous coronary intervention (PCI). Trials conducted in the United States of America have identified cangrelor as a potent and rapid-acting intravenous P2Y12 inhibitor, which has the potential of reducing ischemic events in these patients without an increase in the bleeding. As cangrelor is rarely used in The Netherlands, we conducted a nationwide registry to provide an insight into the use of cangrelor in the management of patients with suboptimal platelet inhibition undergoing (primary) PCI (the Dutch Cangrelor Registry).

STUDY DESIGN

The Cangrelor Registry is a prospective, observational, multicenter, single-arm registry with cangrelor administered pre-PCI in: (1) P2Y12 naive patients with ad-hoc PCI, (2) patients with STEMI/NSTEMI with suboptimal P2Y12 inhibition including (3) stable resuscitated/defibrillated patients with out-of-hospital cardiac arrest (OHCA) due to acute ischemia and (4) STEMI/NSTEMI patients with a high thrombotic burden. Primary endpoint is 48 h Net Adverse Clinical Events (NACE), which is a composite endpoint of all-cause death, recurrent myocardial infarction (MI), target vessel revascularization (TVR), stroke, stent thrombosis (ST) and BARC 2-3-5 bleeding. The Dutch Cangrelor Registry will assess the feasibility and safety of cangrelor in patients with suboptimal P2Y12 inhibition undergoing (primary) PCI in the setting of acute coronary syndrome (ACS) and stable coronary artery disease (CAD) in the Netherlands.

COVID-19 Infection and High Intracoronary Thrombus Burden

Coronavirus 2019 (COVID-19) is an acute respiratory disease that has rapidly spread around the world and been declared a global pandemic by the World Health Organization. Emerging evidence demonstrates a strong association with a pro-thrombotic state and we present the first patient admitted with COVID-19 and an inferior ST-segment elevation myocardial infarction (STEMI) with evidence of high intracoronary thrombus burden. We review the mechanism of the high thrombus burden, which may be driven by the significant cytokine storm, endothelial dysfunction, increase risk of coronary plaque rupture and hypercoagulability.

Routine Glycoprotein IIb/IIIa Inhibitor Therapy in ST-Segment Elevation Myocardial Infarction: A Meta-analysis

BACKGROUND

Guidelines recommend adjunct glycoprotein IIb/IIIa inhibitors (GPIs) only in selected patients with acute ST-segment elevation myocardial infarction (STEMI). This study aimed to evaluate routine GPI use in STEMI treated with primary percutaneous coronary intervention.

METHODS

Online databases were searched for randomized controlled trials of routine GPI vs control therapy in STEMI. Data from retrieved studies were abstracted and evaluated in a comprehensive meta-analysis. Twenty-one randomized controlled trials with 8585 patients were included: 10 trials randomized tirofiban, 9 abciximab, 1 trial eptifibatide, and 1 trial used abciximab+tirofiban; only 1 trial used dual antiplatelet therapy with prasugrel/ticagrelor.

RESULTS

Routine GPI use was associated with a significant reduction in all-cause mortality at 30 days (2.4% [GPI] vs 3.2%; risk ratio [RR], 0.72; P = 0.01) and 6 months (3.7% vs 4.8%; RR, 0.76; P = 0.02), and a reduction in recurrent myocardial infarction (1.1% vs 2.1%; RR, 0.55; P = 0.0006), repeat revascularization (2.5% vs 4.1%; RR, 0.63; P = 0.0001), thrombolysis in myocardial infarction flow <3 after percutaneous coronary intervention (5.4% vs 8.2%; RR, 0.61; P < 0.0001), and ischemic stroke (RR, 0.42; P = 0.04). Major (4.7% vs 3.4%; RR, 1.35; P = 0.005) and minor bleedings (7.2% vs 5.1%; RR, 1.39; P = 0.006) but not intracranial bleedings (0.1% vs 0%; RR, 2.7; P = 0.37) were significantly increased under routine GPI.

CONCLUSIONS

Routine GPI administration in STEMI resulted in a reduction in mortality, driven by reductions in recurrent ischemic events-however predominantly in pre-prasugrel/ticagrelor trials. Trials with contemporary STEMI management are needed to confirm these findings.

Observational Study of Platelet Reactivity in Patients Presenting With ST-Segment Elevation Myocardial Infarction Due to Coronary Stent Thrombosis Undergoing Primary Percutaneous Coronary Intervention: Results From the European PREvention of Stent Thrombosis by an Interdisciplinary Global European Effort Registry

OBJECTIVES

High platelet reactivity (HPR) was studied in patients presenting with ST-segment elevation myocardial infarction (STEMI) due to stent thrombosis (ST) undergoing immediate percutaneous coronary intervention (PCI).

BACKGROUND

HPR on P2Y₁₂ inhibitors (HPR-ADP) is frequently observed in stable patients who have experienced ST. The HPR rates in patients presenting with ST for immediate PCI are unknown.

METHODS

Consecutive patients presenting with definite ST were included in a multicenter ST registry. Platelet reactivity was measured before immediate PCI with the VerifyNow P2Y₁₂ or Aspirin assay.

RESULTS

Platelet reactivity was measured in 129 ST patients presenting with STEMI undergoing immediate PCI. HPR-ADP was observed in 76% of the patients, and HPR on aspirin (HPR-AA) was observed in 13% of the patients. HPR rates were similar in patients who were on maintenance P2Y₁₂ inhibitor or aspirin since stent placement versus those without these medications. In addition, HPR-ADP was similar in patients loaded with a P2Y₁₂ inhibitor shortly before immediate PCI versus those who were not. In contrast, HPR-AA trended to be lower in patients loaded with aspirin as compared with those not loaded.

CONCLUSIONS

Approximately 3 out of 4 ST patients with STEMI undergoing immediate PCI had HPR-ADP, and 13% had HPR-AA. Whether patients were on maintenance antiplatelet therapy while developing ST or loaded with P2Y₁₂ inhibitors shortly before undergoing immediate PCI had no influence on the HPR rates. This raises concerns that the majority of patients with ST have suboptimal platelet inhibition undergoing immediate PCI.

Cangrelor in cardiogenic shock and after cardiopulmonary resuscitation: A global, multicenter, matched pair analysis with oral P2Y12 inhibition from the IABP-SHOCK II trial

AIMS

Cangrelor has a potentially favorable pharmacodynamic profile in cardiogenic shock (CS). We aimed to evaluate the clinical course of CS patients undergoing percutaneous coronary intervention (PCI) treated with cangrelor.

METHODS AND RESULTS

We retrospectively identified 136 CS patients treated with cangrelor. Patients were 1:1 matched to CS patients from the IABP-SHOCK II trial not receiving cangrelor by age, sex, cardiac arrest, type of myocardial infarction, culprit lesion, glycoprotein IIb/IIIa inhibitor, and oral P2Y₁₂-receptor inhibitor and followed-up for 12 months. The study cohort consisted of 88 matched pairs. Thirty-day and 12-month mortality was 29.5% and 34.1% in cangrelor-treated patients and 36.4% and 47.1% in control group (P = 0.34 and P = 0.08, respectively). The rate of definite acute stent thrombosis was 2.3% in both groups. Moderate and severe bleeding events occurred in 21.6% in the cangrelor and 19.3% in the control group (P = 0.71). Patients treated with cangrelor more frequently experienced ≥1 TIMI flow grade improvement during PCI (92.9% vs. 81.2%, P = 0.02).

CONCLUSION

Cangrelor treatment was associated with similar bleeding risk and significantly better TIMI flow improvement compared with oral P2Y₁₂ inhibitors in CS patients undergoing PCI. The use of cangrelor in CS offers a potentially safe and effective antiplatelet option and should be evaluated in randomized trials.

Intravenous antiplatelet therapies (glycoprotein IIb/IIIa receptor inhibitors and cangrelor) in percutaneous coronary intervention: from pharmacology to indications for clinical use

Oral antiplatelet drugs are crucially important for patients with acute coronary syndrome or stable coronary artery disease undergoing percutaneous coronary intervention (PCI). In recent decades, several clinical trials have focused on reducing periprocedural ischemic events in patients undergoing PCI by means of more rapid platelet inhibition with the use of intravenous antiplatelet drugs. Glycoprotein IIb/IIIa receptor inhibitors (GPIs) block the final common pathway of platelet aggregation and enable potent inhibition in the peri-PCI period. In recent years, however, the use of GPIs has decreased due to bleeding concerns and the availability of more potent oral P2Y12 inhibitors. Cangrelor is an intravenous P2Y12 receptor antagonist. In a large-scale regulatory trial, cangrelor administration during PCI allowed for rapid, potent and rapidly reversible inhibition of platelet aggregation, with an anti-ischemic benefit and no increase in major bleeding. This article aims to provide an overview of general pharmacology, supporting evidence and current status of intravenous antiplatelet therapies (GPIs and cangrelor), with a focus on contemporary indications for their clinical use.

Pharmacosimulation of interruptions and its solution in intravenous administration of cangrelor

BACKGROUND

Cangrelor is an intravenous adenosine diphosphate (ADP) P2Y12 receptor antagonist, which has to be administered as a bolus followed by immediate infusion. Nevertheless, in clinical routine deviations from the correct practice, such as delayed infusion onset or interruptions during infusion, may occur.

OBJECTIVE

The objective of the present study was to investigate the impact of administration delays on cangrelor concentration in a pharmacological simulation setting and to give possible solutions for the clinical practice.

METHODS

We simulated the effects of different delays in administration of cangrelor in a model based on known pharmacokinetic parameters. Additionally, we calculated the optimal dosage of a second bolus.

RESULTS

We demonstrate that already a short delay between the bolus and begin of infusion as well as short infusion interruptions considerably affect the serum concentration of cangrelor. Additionally, we estimate the dosage of a possible second bolus which highly depends on the duration of the delay.

CONCLUSIONS

Our results emphasize that continuous administration of cangrelor is crucial to avoid the critical time frame of increased thrombosis risk. We suggest a strategy for dealing with interruptions by demonstrating that a second bolus allows to reach rapidly an effective but not excessive cangrelor serum concentration.

Erythropoietin therapy after out-of-hospital cardiac arrest: A systematic review and meta-analysis

AIM

To assess safety and efficacy of early erythropoietin (Epo) administration in patients with out-of-hospital cardiac arrest (OHCA).

METHODS

A systematic literature search was performed using PubMed, MEDLINE, EMBASE, EBSCO, CINAHL, Web of Science and Cochrane databases, of all studies published from the inception through October 10, 2016. Inclusion criteria included: (1) Adult humans with OHCA and successful sustained return of spontaneous circulation; and (2) studies including mortality/brain death, acute thrombotic events as their end points. Primary efficacy outcome was “brain death or Cerebral Performance Category (CPC) score of 5”. Secondary outcomes were “CPC score 1, and 2-4”, “overall thrombotic events” and “acute coronary stent thrombosis”.

RESULTS

We analyzed a total of 606 participants (n = 276 received Epo and n = 330 with standard of care alone) who experienced OHCA enrolled in 3 clinical trials. No significant difference was observed between the Epo and no Epo group in brain death or CPC score 5 (OR = 0.77; 95%CI: 0.42-1.39), CPC score 1 (OR = 1.16, 95%CI: 0.82-1.64), and CPC score 2-4 (OR = 0.77, 95%CI: 0.44-1.36). Epo group was associated with increased thrombotic complications (OR = 2.41, 95%CI: 1.26-4.62) and acute coronary stent thrombosis (OR = 8.16, 95%CI: 1.39-47.99). No publication bias was observed.

CONCLUSION

Our study demonstrates no improvement in neurological outcomes and increased incidence of thrombotic events and acute coronary stent thrombosis in OHCA patients who were treated with Epo in addition to standard therapy.

Clopidogrel in Critically Ill Patients

Only limited data are available regarding the treatment of critically ill patients with clopidogrel. This trial investigated the effects and the drug concentrations of the cytochrome P450 (CYP450) activated prodrug clopidogrel (n = 43) and the half‐life of the similarly metabolized pantoprazole (n = 16) in critically ill patients. ADP‐induced aggregometry in whole blood classified 74% (95% confidence intervals 59–87%) of critically ill patients as poor responders (n = 43), and 65% (49–79%) responded poorly according to the vasodilator‐stimulated phosphoprotein phosphorylation (VASP‐P) assay. Although the plasma levels of clopidogrel active metabolite normally exceed the inactive prodrug ∼30‐fold, the parent drug levels even exceeded those of the metabolite 2‐fold in critically ill patients. The half‐life of pantoprazole was several‐fold longer in these patients compared with reference populations. The inverse ratio of prodrug/active metabolite indicates insufficient metabolization of clopidogrel, which is independently confirmed by the ∼5‐fold increase in half‐life of pantoprazole. Thus, high‐risk patients may benefit from treatment with alternative platelet inhibitors.

Role of New Antiplatelet Drugs on Cardiovascular Disease: Update on Cangrelor

Dual therapy with a P2Y₁₂ receptor antagonist in addition to aspirin is the antiplatelet treatment of choice in patients with acute coronary syndromes or undergoing percutaneous coronary intervention (PCI). However, available oral P2Y₁₂ antagonists have several limitations, mostly due to their pharmacological profile, which can affect outcomes in certain clinical settings. Cangrelor is an intravenous, direct-acting, potent P2Y₁₂ inhibitor with rapid onset and offset of action, which has been recently approved for clinical use in patients undergoing PCI. In clinical trials, cangrelor has demonstrated greater efficacy than clopidogrel with a favorable safety profile among PCI patients not receiving pretreatment with oral P2Y₁₂ antagonists. However, its definitive role in contemporary practice is yet to be determined. This review aims to provide a comprehensive overview of the current status of knowledge on cangrelor, focusing on its pharmacological properties, clinical development, and the potential applications of this newly available agent.

Therapeutic Hypothermia and Stent Thrombosis: A Nationwide Analysis

OBJECTIVES

This study sought to determine whether "real-world" data supported the hypothesis that therapeutic hypothermia (TH) led to increased rates of stent thrombosis.

BACKGROUND

TH, which is often instituted after cardiac arrest (CA) to improve neurologic outcomes, alters pharmacokinetics of antiplatelet medications, leading to a theoretical risk of stent thrombosis after percutaneous coronary intervention (PCI).

METHODS

CA patients with acute myocardial infarction undergoing PCI were identified from the Nationwide Inpatient Sample from 2006 to 2011, with a defined primary outcome of stent thrombosis. The incidence of stent thrombosis in patients undergoing TH versus those not undergoing TH was compared using both logistic regression and propensity score matching.

RESULTS

In this dataset, 49,109 CA patients underwent PCI for acute myocardial infarction from 2006 to 2011, of whom 1,193 (2.4%) underwent TH. The incidence of stent thrombosis in the TH group was 3.9% (43 of 1,193), compared to 4.7% (2,271 of 47,916) in the no TH group (p = 0.61). Logistic regression showed that TH was not a significant predictor of stent thrombosis with an adjusted odds ratio of 0.71 (95% confidence interval: 0.28 to 1.76; p = 0.46). Propensity matching was performed to adjust for baseline differences between the TH and no TH groups, matching 1,155 patients in the TH group with 3,399 patients in the no TH group. No difference was observed in the incidence of stent thrombosis in the TH and the no TH groups after propensity matching (3.5% vs. 6.1%; p = 0.17).

CONCLUSIONS

TH does not increase the incidence of stent thrombosis after primary PCI in patients with acute myocardial infarction presenting as CA.

Cangrelor With and Without Glycoprotein IIb/IIIa Inhibitors in Patients Undergoing Percutaneous Coronary Intervention

BACKGROUND

Cangrelor, an intravenous, reversible P2Y₁₂ antagonist, is approved for use in patients undergoing percutaneous coronary intervention (PCI).

OBJECTIVES

This study sought to evaluate the efficacy and safety of cangrelor compared with clopidogrel in subgroups that did and did not receive glycoprotein IIb/IIIa inhibitors (GPIs).

METHODS

This pooled, patient-level analysis of the 3 CHAMPION (Cangrelor versus Standard Therapy to Achieve Optimal Management of Platelet Inhibition) trials analyzed all randomized patients who underwent PCI and received the study drug (n = 24,902). Only bailout/rescue GPI use was permitted, except in CHAMPION PCI, in which routine or bailout/rescue GPI use was at the site investigator's discretion. The primary efficacy endpoint was the composite of all-cause mortality, myocardial infarction, ischemia-driven revascularization, or stent thrombosis at 48 h after randomization.

RESULTS

Overall, 3,173 patients (12.7%) received a GPI, most commonly eptifibatide (69.4%). Despite variation in indications for GPIs, baseline characteristics were well balanced between the cangrelor and clopidogrel arms in subsets receiving and not receiving GPIs. Rates of the primary composite endpoint were lower with cangrelor compared with clopidogrel in patients who did (4.9% vs. 6.5%; odds ratio [OR]: 0.74; 95% confidence interval [CI]: 0.55 to 1.01) or did not receive a GPI (3.6% vs. 4.4%; OR: 0.82; 95% CI: 0.72 to 0.94; P_int = 0.55). Cangrelor did not increase the primary safety endpoint, GUSTO-defined severe/life-threatening bleeding, in patients who did (0.4% vs. 0.5%; OR: 0.71; 95% CI: 0.25 to 1.99) or did not receive GPIs (0.2% vs. 0.1%; OR: 1.56; 95% CI: 0.80 to 3.04; P_int = 0.21). GPI use was associated with increased risk of bleeding in both treatment arms.

CONCLUSIONS

Cangrelor's efficacy in reducing ischemic complications in patients undergoing PCI was maintained irrespective of GPI administration. GPI use was associated with substantially higher bleeding rates, regardless of the randomization to cangrelor or clopidogrel. (A Clinical Trial to Demonstrate the Efficacy of Cangrelor [PCI]: NCT00305162; Cangrelor Versus Standard Therapy to Achieve Optimal Management of Platelet Inhibition [PLATFORM]: NCT00385138; A Clinical Trial Comparing Cangrelor to Clopidogrel Standard Therapy in Subjects Who Require Percutaneous Coronary Intervention [PCI] [CHAMPION PHOENIX] [CHAMPION]: NCT01156571).

Optimizing the Use of Cangrelor in the Real World

Thrombotic events such as myocardial infarction or stent thrombosis are the major cause of adverse outcomes in patients undergoing percutaneous coronary intervention (PCI). While current antiplatelet agents, anticoagulants, and PCI techniques have reduced the risk of thrombotic events in PCI-treated patients, a considerable hazard still remains. Cangrelor is an intravenous P2Y12 receptor antagonist that provides a rapid onset and maximal platelet inhibition, which is quickly reversible. In the large-scale CHAMPION PHOENIX trial, cangrelor was shown to reduce ischemic events significantly, including myocardial infarction and stent thrombosis, without increasing the risk of severe bleeding across the full spectrum of patients undergoing PCI, with substantial benefits in all patient subgroups examined. The pharmacologic profile of cangrelor makes it a valuable addition to the armamentarium of physicians providing care to a broad range of patients with coronary artery disease. Cangrelor is currently approved for reducing thrombotic events in patients undergoing PCI who have not been pretreated with a P2Y12 receptor inhibitor and are not receiving a glycoprotein IIb/IIIa inhibitor. Future studies are needed to determine the role of cangrelor in other clinical settings, such as upstream therapy in ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation acute coronary syndrome (NSTE-ACS), and as a bridge to coronary artery bypass graft (CABG) or other non-cardiac surgeries in patients who require ongoing adenosine diphosphate receptor blockade.

Primary Angioplasty For Patients in Cardiogenic Shock: Optimal Management

Cardiogenic shock complicates approximately 5-10 % of all MI events and remains the most common cause of death among MI cases. Over the past few decades, the mortality rate associated with cardiogenic shock has decreased with the introduction of early revascularisation, although there are limited data for patients with triple-vessel disease and left main stem disease. In more recent years, there have been a number of advances in the mechanical circulatory support devices that can help improve the haemodynamics of patients in cardiogenic shock. Despite these advances, together with progress in the use of inotropes and vasopressors, cardiogenic shock remains associated with high morbidity and mortality rates. This review will outline the management of cardiogenic shock complicating acute MI with a smajor focus on revascularisation techniques and the use of mechanical circulatory support devices.

Current status of data on cangrelor

P2Y12 receptor inhibition in addition to aspirin is the cornerstone of treatment in patients with acute coronary syndromes (ACS) and those undergoing percutaneous coronary intervention (PCI). Despite advances in contemporary antithrombotic therapy, periprocedural thrombotic complications such as myocardial infarction and stent thrombosis remain a major concern in patients treated with PCI. Current practice guidelines recommend treatment with a P2Y12 receptor inhibitor as early as possible in patients with ACS. Existing oral P2Y12 receptors inhibitors (clopidogrel, prasugrel, or ticagrelor) have several limitations such as delayed onset and offset of action, interindividual variation, and only oral availability. Cangrelor, an intravenous, fast-onset, direct-acting P2Y12 receptor inhibitor offers potent platelet inhibition that is rapidly reversible. In large randomized trials, cangrelor has shown substantial reduction in ischemic events with no increase in severe bleeding compared with clopidogrel among patients undergoing PCI. Cangrelor is approved as an adjunct to PCI to reduce the risk of periprocedural MI, repeat coronary revascularization, and stent thrombosis in patients who have not been pretreated with a P2Y12 receptor inhibitor and are not receiving a glycoprotein IIb/IIIa inhibitor. This review aims at providing a comprehensive analysis of the current evidence pertaining to the role of cangrelor in contemporary practice.

Anti-platelet Therapy Resistance - Concept, Mechanisms and Platelet Function Tests in Intensive Care Facilities

It is well known that critically ill patients require special attention and additional consideration during their treatment and management. The multiple systems and organ dysfunctions, typical of the critical patient, often results in different patterns of enteral absorption in these patients. Anti-platelet drugs are the cornerstone in treating patients with coronary and cerebrovascular disease. Dual anti-platelet therapy with aspirin and clopidogrel is the treatment of choice in patients undergoing elective percutaneous coronary interventions and is still widely used in patients with acute coronary syndromes. However, despite the use of dual anti-platelet therapy, some patients continue to experience cardiovascular ischemic events. Recurrence of ischemic events is partly attributed to the fact that some patients have poor inhibition of platelet reactivity despite treatment. These patients are considered low- or non-responders to therapy. The underlying mechanisms leading to resistance are not yet fully elucidated and are probably multifactorial, cellular, genetic and clinical factors being implicated. Several methods have been developed to asses platelet function and can be used to identify patients with persistent platelet reactivity, which have an increased risk of thrombosis. In this paper, the concept of anti-platelet therapy resistance, the underlying mechanisms and the methods used to identify patients with low responsiveness to anti-platelet therapy will be highlighted with a focus on aspirin and clopidogrel therapy and addressing especially critically ill patients.

The effect of targeted temperature management on coagulation parameters and bleeding events after out-of-hospital cardiac arrest of presumed cardiac cause

AIMS

Targeted temperature management (TTM) is part of the standard treatment of comatose patients after out-of-hospital cardiac arrest (OHCA) to attenuate neurological injury. In other clinical settings, hypothermia promotes coagulopathy leading to an increase in bleeding and thrombosis tendency. Thus, concern has been raised as to whether TTM can be applied safely, as acute myocardial infarction requiring primary percutaneous coronary intervention (PCI) with the need of effective antiplatelet therapy is frequent following OHCA. This study investigated the influence of TTM at 33 or 36°C on various laboratory and coagulation parameters.

METHODS AND RESULTS

In this single-center predefined substudy of the TTM trial, 171 patients were randomized to TTM at either 33 or 36°C in the postresuscitation phase. The two subgroups were compared regarding standard laboratory coagulation parameters, thrombelastography (TEG), bleeding, and stent thrombosis events. Platelet counts were lower in the TTM33-group compared to TTM36 (p=0.009), but neither standard coagulation nor TEG-parameters showed any difference between the groups. TEG revealed a normocoagulable state in the majority of patients, while approximately 20% of the population presented as hypercoagulable. Adverse events included 38 bleeding events, one stent thrombosis, and one reinfarction, with no significant difference between the groups.

CONCLUSIONS

There was no evidence supporting the assumption that TTM at 33°C was associated with impaired hemostasis or increased the frequency of adverse bleeding and thrombotic events compared to TTM at 36°C. We found that TTM at either temperature can safely be applied in the postresuscitation phase after acute myocardial infarction and primary PCI.

Temperature effects on haemostasis in whole blood from ticagrelor- and aspirin-treated patients with acute coronary syndrome

BACKGROUND

Comatose survivors after cardiac arrest are treated with mild induced hypothermia and potent platelet- inhibiting drugs after coronary stenting. Previous studies have shown an increased incidence of stent thrombosis during clopidogrel and aspirin treatment in conjunction with induced hypothermia. The aim of this study was to investigate the in vitro effect of induced hypo- and hyperthermia on blood from patients undergoing ticagrelor- and aspirin-mediated platelet inhibition.

METHODS

Whole blood from 15 patients with acute coronary syndrome who were treated with ticagrelor and aspirin and from eight healthy volunteers was incubated for 1 hour at 28, 33, 37, and 39°C.

RESULTS

In blood from patients with acute coronary syndrome, the activated clotting time (Sonoclot) was prolonged in mild hypothermic (33°C) compared to normothermic (37°C) samples. Sonoclot, clotting rate and platelet function were decreased in hypothermic compared to normothermic samples. Platelet-induced activation and aggregation (Multiplate) was unchanged in mild hypothermic compared to normothermic samples. In contrast, mild hypothermia supported increased platelet activation as measured with flow cytometry with up-regulation of PAC-1 and P-selectin on the platelet surface.

CONCLUSION

In acute coronary syndrome patients treated with ticagrelor and aspirin, in vitro hypothermia to 33°C markedly increased platelet activity measured with flow cytometry, whereas viscoelastic coagulation test (Sonoclot) revealed a hypocoagulative response. Prospective clinical trials studying platelet inhibition at different temperatures and correlating changes in platelet function to bleeding or stent occlusion are needed.

Platelet aggregation and clot formation in comatose survivors of cardiac arrest treated with induced hypothermia and dual platelet inhibition with aspirin and ticagrelor; a prospective observational study

INTRODUCTION

We conducted a prospective observational study in cardiac arrest survivors treated with mild induced hypothermia, evaluating different platelet function tests at hypo- and normothermia. We also investigated the relation between gastric emptying and vasodilator stimulated phosphoprotein (VASP).

METHODS

Comatose survivors of out of hospital cardiac arrest were included and divided into two groups, depending on whether dual platelet inhibition with peroral ticagrelor and aspirin was given or not. The first blood samples (T1) were collected 12-24 hours after reaching target temperature (33°C) and were compared to blood samples collected 12-28 hours after reaching normothermia (37°C) (T2) within each group. All samples were analysed by Sonoclot viscoelasticity, flow cytometry based VASP and with multiple electrode aggregometry, Multiplate®; adenosine diphosphate (ADP), collagen (COL), thrombin receptor agonist peptide (TRAP) and arachidonic acid (ASPI). Sonoclot and Multiplate® instruments were set on in vivo temperatures. Gastric secretion from the nasogastric tube was measured to assess absorption of per orally administered antiplatelet drugs. Differences between T1 and T2 within each group were calculated using Wilcoxon matched pairs signed test. Significance levels were set at P <0.01.

RESULTS

In total, 23 patients were included. In patients with dual platelet inhibition (n =14) Multiplate®-analyses showed no changes in ADP stimulated platelets. COL, TRAP and ASPI aggregations were higher at T2 compared to T1. Sonoclot-analyses showed that activated clotting time (ACT) was unchanged but both clot rate (CR) and platelet function (PF) were higher at T2 compared to T1. VASP decreased from 53 ± 28(T1) to 24 ± 22(T2), (P <0.001). The average volume of gastric secretion aspirated before T1 correlated well with VASP (T1), r =0.81 (P <0.001). In patients with no platelet inhibition, (n =9) similar changes between T1 and T2 were seen as in patients with dual platelet inhibition while VASP was unchanged.

CONCLUSIONS

We have demonstrated increased platelet aggregation and strengthened clot formation over time in out of hospital cardiac arrest patients treated with hypothermia. In patients on oral dual platelet inhibition, the effect of ticagrelor was delayed, probably due to slow gastric emptying.

Safety of therapeutic hypothermia combined with primary percutaneous coronary intervention after out-of-hospital cardiac arrest

Background:

The safety of therapeutic hypothermia combined with percutaneous coronary intervention (PCI) after out-of-hospital cardiac arrest has been challenged after reports of high risk of stent thrombosis.

Methods:

We searched the Western Denmark Heart Registry to identify patients with an acute coronary angiography due to out-of-hospital cardiac arrest performed at our institution between September 2010 and September 2013. We identified 68 unconscious patients, who were resuscitated after out-of-hospital cardiac arrest and underwent acute PCI with stent implantation and immediate therapeutic hypothermia, and followed these for 30 days. Target temperature of 32-34°C was achieved by either an invasive or a non-invasive cooling system.

Results:

All patients had elevated myocardial biomarkers and 37 patients had ST-segment elevation myocardial infarction. Bare metal stents were implanted in 14 and drug-eluting stents in 54 patients. All patients received antithrombotic treatment with a standard loading dose of 300 mg acetylsalicylic acid and 10,000 units heparin intravenously prior PCI. Clopidogrel or ticagrelor was administered orally through a gastric tube immediately after PCI. During the procedure abciximab or bivalirudin was administered in 44 patients. Electrocardiographic and clinical signs of stent thrombosis were found in one patient.

Conclusions:

We observed one stent thrombosis in this cohort of 68 consecutive patients with out-of-hospital cardiac arrest who were treated with PCI and therapeutic hypothermia. This suggests that PCI with stent implantation can be performed with acceptable safety in these patients.

Cangrelor: an emerging therapeutic option for patients with coronary artery disease

OBJECTIVES

To perform a systematic up-to-date review and critical discussion of potential clinical applications of cangrelor based on its pharmacologic properties and the main findings from randomized clinical studies.

METHODS

A database search (PubMed, CENTRAL and Google Scholar) by two independent investigators, including proceedings from scientific sessions of ACC, AHA, ESC, TCT and EuroPCR, from January 1998 through December 2013.

RESULTS

Cangrelor is a potent, intravenous, direct-acting P2Y12 antagonist with rapid onset and quickly reversible action. In contrast to ticagrelor, cangrelor's interaction with thienopiridines requires termination of cangrelor infusion before switching to clopidogrel or prasugrel. According to randomized trials, a cangrelor-clopidogrel combination is relatively safe and more effective than the standard clopidogrel regimen in both urgent and elective percutaneous coronary intervention (PCI) settings, with the advantage of this drug combination fully evident when the universal definition of myocardial infarction is applied. In contrast to available antiplatelet drugs with delayed onset and offset of action, its favorable properties make cangrelor a desirable agent for ad hoc elective PCI, high risk acute coronary syndromes treated with immediate coronary stenting and for bridging those surgery patients who require periprocedural P2Y12 inhibition. Current evidence on cangrelor therapy is limited by the lack of adequately powered studies assessing cangrelor co-administration either with prasugrel or ticagrelor, suboptimal design of some of the trials favoring cangrelor, potentially attenuated benefits with modern stent design, and finally, by the lack of survival advantage.

CONCLUSIONS

With its pharmacokinetic and pharmacodynamic advantages, allowing consistent and strong P2Y12 inhibition, and with its rapid onset and swift reversal of action devoid of need for an antidote, cangrelor might improve clinical outcomes in clopidogrel-treated patients by reducing ischemic events, while maintaining a favorable safety profile. However, further studies, addressing the safety and efficacy of cangrelor on top of novel oral P2Y12 inhibitors, are warranted.

Impact of new oral or intravenous P2Y12 inhibitors and clopidogrel on major ischemic and bleeding events in patients with coronary artery disease: a meta-analysis of randomized trials

OBJECTIVE

New P2Y12 inhibitors can be classified as oral (prasugrel and ticagrelor) and intravenous drugs (cangrelor and elinogrel). These P2Y12 inhibitors might be superior to clopidogrel for reducing ischemic events in patients with coronary artery disease (CAD). We performed a meta-analysis of randomized trials that compared new oral or intravenous P2Y12 inhibitors with clopidogrel to determine their efficacy and safety in patients.

METHODS AND RESULTS

Twelve randomized, placebo-controlled studies and two subgroup analyses of included studies on ST-segment elevation myocardial infarction (STEMI) were included. The database consisted of 82,784 patients, with 43,875 (53%) on new oral P2Y12 inhibitors and 38909 (47%) on intravenous P2Y12 inhibitors compared with clopidogrel. The primary efficacy endpoint was major adverse cardiac events (MACEs). The primary safety endpoint was thrombolysis in myocardial infarction (TIMI) major bleeding. New oral P2Y12 inhibitors significantly decreased MACEs (odds ratio: 0.85, p<0.0001 for the whole cohort; OR: 0.77, p=0.04 for STEMI) and all-cause death (OR: 0.88, p=0.04 for the whole cohort; OR: 0.77, p=0.01 for STEMI). Among new intravenous P2Y12 inhibitors, only cangrelor significantly decreased the risk of MACEs. An increase in TIMI major bleeding was observed only by prasugrel among the new P2Y12 inhibitors.

CONCLUSIONS

New oral P2Y12 inhibitors reduce ischemic events, but there is no obvious increase in major bleeding in patients with CAD, and the risk/benefit ratio is particularly favorable for STEMI patients. Moreover, only cangrelor is beneficial for ischemic events in patients on new intravenous P2Y12 inhibitors.