Superiority of Ticagrelor Over Clopidogrel in Patients After Cardiac Arrest Undergoing Therapeutic Hypothermia

Recovery and Survival of Patients After Out-of-Hospital Cardiac Arrest: A Literature Review Showcasing the Big Picture of Intensive Care Unit-Related Factors

As an important public health issue, out-of-hospital cardiac arrest (OHCA) requires several stages of high quality medical care, both on-field and after hospital admission. Post-cardiac arrest shock can lead to severe neurological injury, resulting in poor recovery outcome and increased risk of death. These characteristics make this condition one of the most important issues to deal with in post-OHCA patients hospitalized in intensive care units (ICUs). Also, the majority of initial post-resuscitation survivors have underlying coronary diseases making revascularization procedure another crucial step in early management of these patients. Besides keeping myocardial blood flow at a satisfactory level, other tissues must not be neglected as well, and maintaining mean arterial pressure within optimal range is also preferable. All these procedures can be simplified to a certain level along with using targeted temperature management methods in order to decrease metabolic demands in ICU-hospitalized post-OHCA patients. Additionally, withdrawal of life-sustaining therapy as a controversial ethical topic is under constant re-evaluation due to its possible influence on overall mortality rates in patients initially surviving OHCA. Focusing on all of these important points in process of managing ICU patients is an imperative towards better survival and complete recovery rates.

Optimal Antithrombotic Strategies in Cardiogenic Shock

Cardiogenic shock (CS) represents a critical condition with a high mortality rate. The most common cause of CS is coronary artery disease, and patients typically present with myocardial infarction, necessitating immediate treatment through percutaneous coronary intervention (PCI) and often requiring mechanical circulatory support. CS is associated with a prothrombotic situation, while on the other hand, there is often a significant risk of bleeding. This dual challenge complicates the selection of an optimal antithrombotic strategy. The choice of antithrombotic agents must be personalized, taking into consideration all relevant conditions. Repeated risk assessment, therapeutic monitoring, and adjusting antithrombotic therapy are mandatory in these patients. This review article aims to provide an overview of the current evidence and practical guidance on antithrombotic strategies in the context of CS.

Comparison of Clopidogrel Versus Ticagrelor for Percutaneous Coronary Intervention (PCI) Patients Managed with Therapeutic Hypothermia: A Systematic Review and Meta-Analysis

Various antiplatelet drugs, such as clopidogrel and ticagrelor, are available on the market for use after percutaneous coronary intervention (PCI). However, the efficacy of such drugs in patients being managed with therapeutic hypothermia (TH) has always been debated. In light of this controversy, this systematic review and meta-analysis was performed to enhance existing literature. Various databases were searched for potentially relevant studies from inception to April 2023, including PubMed, Cochrane Library, and Scopus. The risk of bias was assessed using the Newcastle-Ottawa scale for cohort studies and the Cochrane risk of bias tool for randomized controlled trials. Outcomes of interest included risk of bleeding, stent thrombosis, and all-cause mortality. Five studies were shortlisted for inclusion into the meta-analysis, featuring a total of 245 patients receiving either clopidogrel or ticagrelor. Overall, no significant differences were noted when the use of clopidogrel and ticagrelor was compared in PCI patients being managed with TH. To the best of our knowledge, this is the most comprehensive meta-analysis comparing the outcomes of clopidogrel and ticagrelor in PCI patients being managed with TH. Despite existing studies claiming an altered efficacy of clopidogrel in such conditions, our meta-analytic findings could not prove this relationship. Due to the limited sample size, further comprehensive and randomized studies are encouraged to arrive at a robust conclusion.

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.

Antithrombotic and anticoagulation therapies in cardiogenic shock: a critical review of the published literature

Cardiogenic shock (CS) is a complex multifactorial clinical syndrome, developing as a continuum, and progressing from the initial insult (underlying cause) to the subsequent occurrence of organ failure and death. There is a large phenotypic variability in CS, as a result of the diverse aetiologies, pathogenetic mechanisms, haemodynamics, and stages of severity. Although early revascularization remains the most important intervention for CS in settings of acute myocardial infarction, the administration of timely and effective antithrombotic therapy is critical to improving outcomes in these patients. In addition, other clinical settings or non-acute myocardial infarction aetiologies, associated with high thrombotic risk, may require specific regimens of short-term or long-term antithrombotic therapy. In CS, altered tissue perfusion, inflammation, and multi-organ dysfunction induce unpredictable alterations to antithrombotic drugs' pharmacokinetics and pharmacodynamics. Other interventions used in the management of CS, such as mechanical circulatory support, renal replacement therapies, or targeted temperature management, influence both thrombotic and bleeding risks and may require specific antithrombotic strategies. In order to optimize safety and efficacy of these therapies in CS, antithrombotic management should be more adapted to CS clinical scenario or specific device, with individualized antithrombotic regimens in terms of type of treatment, dose, and duration. In addition, patients with CS require a close and appropriate monitoring of antithrombotic therapies to safely balance the increased risk of bleeding and thrombosis.

Balancing thrombosis and bleeding after out-of-hospital cardiac arrest related to acute coronary syndrome: A literature review

Balance between thrombosis and bleeding is now well recognized in patients treated for acute coronary syndrome, with impact on short- and long-term prognosis, including survival. Recent data suggest that patients who are resuscitated after out-of-hospital cardiac arrest related to myocardial infarction are at an even higher risk of bleeding and thrombosis than those with uncomplicated acute coronary syndrome. Delayed enteral absorption of medication due to induced hypothermia and systemic inflammation increases thrombosis risk, whereas transfemoral access site, cardiopulmonary resuscitation manoeuvres and mechanical circulatory support devices increase bleeding risk. In addition, post-resuscitation syndrome and renal or hepatic impairment are potential risk factors for both bleeding and thrombotic complications. There are currently no randomized controlled trials comparing various P₂Y₁₂ inhibitor and/or anticoagulation strategies in the setting of out-of-hospital cardiac arrest, and current practice is largely derived from management of patients with uncomplicated acute coronary syndrome. The aim of this review is therefore to describe the bleeding and thrombosis risk factors in this specific population, and to review recent data on antithrombotic drugs in this patient subset.

Outcomes Related to Antiplatelet Therapy in a High-Risk ST-Segment Elevation Myocardial Infarction Population: A Retrospective Real-World Analysis of an Italian ECMO Center

AIM

To evaluate outcomes related to antiplatelet therapy in patients with ST-elevation myocardial infarction (STEMI) admitted to the San Gerardo Hospital in Monza, an extracorporeal membrane oxygenation (ECMO) reference center in the Monza-Brianza area.

METHODS

This retrospective study enrolled patients with STEMI hospitalized between 2013 and 2017.

RESULTS

This study included 653 patients (mean age: 67.5 years, 71% male). Across the study period, ticagrelor use showed consistent increases, from 22% of patients during 2013 to 85% in 2017. Cardiac arrest prehospitalization occurred in 100 patients (15.3%), either at home (n = 85, 13.0%) or during transfer (n = 15, 2.3%); 46 patients underwent ECMO for refractory cardiac arrest. Rates of 90-day survival (hazard ratio [HR]: 2.4, 95% confidence interval [CI]: 1.3-4.4, P = .004) and ST resolution (odds ratio [OR]: 2.5, 95% CI: 1.6-4.1, P = .000) were higher with ticagrelor than with other antiplatelet agents. When analyzed by each agent, patients on ticagrelor had longer survival (HR: 0.4, 95% CI: 0.2-0.8, P = .008) than patients on clopidogrel and more frequent ST resolution than those on clopidogrel or prasugrel (OR: 0.4, 95% CI: 0.2-0.7, P = .002 and OR: 0.4, 95% CI: 0.2-0.7, P = .006). There was no difference in mortality between ticagrelor and prasugrel.

CONCLUSIONS

Changes in the treatment of high-risk patients with STEMI over time are in line with changes in treatment guidelines. In these patients, ticagrelor is associated with significantly improved 90-day mortality compared with clopidogrel.

Contemporary Management of Out-of-hospital Cardiac Arrest in the Cardiac Catheterisation Laboratory: Current Status and Future Directions

Out-of-hospital cardiac arrest (OHCA) is an important cause of mortality and morbidity in developed countries and remains an important public health burden. A primary cardiac aetiology is common in OHCA patients, and so patients are increasingly brought to specialist cardiac centres for consideration of coronary angiography, percutaneous coronary intervention and mechanical circulatory support. This article focuses on the management of OHCA in the cardiac catheterisation laboratory. In particular, it addresses conveyance of the OHCA patient direct to a specialist centre, the role of targeted temperature management, pharmacological considerations, provision of early coronary angiography and mechanical circulatory support.

Impact of mild therapeutic hypothermia on bioavailability of ticagrelor in patients with acute myocardial infarction after out-of-hospital cardiac arrest

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) frequently occurs in the early phase of acute myocardial infarction (MI). Survivors require percutaneous coronary intervention (PCI) with concomitant dual antiplatelet therapy. Target temperature management, including mild therapeutic hypothermia (MTH), should be applied in comatose patients after resuscitation. However, an increased risk of stent thrombosis in patients undergoing hypothermia is observed. The aim of this study was to assess the impact of MTH on pharmacokinetics of ticagrelor in cardiac arrest survivors with MI treated with MTH and PCI.

METHODS

In a prospective, observational, single-center study pharmacokinetics of ticagrelor were evaluated in 41 MI patients, including 11 patients after OHCA undergoing MTH (MTH group) and 30 MI patients without OHCA and MTH (no-MTH group). Blood samples were drawn before administration of a 180 mg ticagrelor loading dose, and 30 min, 1, 2, 4, 6, 12, and 24 h after the loading dose.

RESULTS

In patients treated with MTH total exposure to ticagrelor during the first 12 h after the loading dose and maximal plasma concentration of ticagrelor were significantly lower than in the no-MTH group (AUC(0-12): 3403 ± 2879 vs. 8746 ± 5596 ng·h/mL, difference: 61%, p = 0.01; Cmax: 475 ± 353 vs. 1568 ± 784 ng/mL, p = 0.0002). Time to achieve maximal ticagrelor plasma concentration was also delayed in the MTH group (tmax for ticagrelor: 12 [6-24] vs. 4 [2-12] h, p = 0.01).

CONCLUSIONS

Bioavailability of ticagrelor was substantially decreased and delayed in MI patients treated with MTH after OHCA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02611934.

Cardiac Intensive Care Unit Management of Patients After Cardiac Arrest: Now the Real Work Begins

Survival with a good quality of life after cardiac arrest continues to be abysmal. Coordinated resuscitative care does not end with the effective return of spontaneous circulation (ROSC)-in fact, quite the contrary is true. Along with identifying and appropriately treating the precipitating cause, various components of the post-cardiac arrest syndrome also require diligent observation and management, including post-cardiac arrest neurologic injury and myocardial dysfunction, systemic ischemia-reperfusion phenomenon with potential consequent multiorgan failure, and the various sequelae of critical illness. There is growing evidence that an early invasive approach to coronary reperfusion with percutaneous coronary intervention, together with active targeted temperature management and optimization of hemodynamic, ventilator, and metabolic parameters, may improve survival and neurologic outcomes in cardiac arrest survivors. Neuroprognostication is complex, as are survivorship issues and long-term rehabilitation. Our paramedics, emergency physicians, and resuscitation specialists are all to be congratulated for ever-increasing success with ROSC… but now the real work begins.

Clopidogrel Versus Newer P2Y12 Antagonists for Percutaneous Coronary Intervention in Patients with Out-of-Hospital Cardiac Arrest Managed with Therapeutic Hypothermia: A Meta-Analysis

Introduction

The impact of therapeutic hypothermia (TH) on outcomes of percutaneous coronary intervention (PCI) and the optimal antiplatelet treatment remains debatable.

Methods

Electronic databases were searched for randomized trials and observational studies to evaluate the available clinical evidence comparing the use of clopidogrel versus newer P2Y12 antagonists in cases of TH after PCI. The primary outcome was in-hospital definite stent thrombosis while the secondary outcomes were in-hospital mortality and major bleeding. Fixed-effects risk ratios (RRs) were estimated using Mantel–Haenszel method.

Results

The final analysis included five studies with a total of 290 patients. There was no difference in the incidence of stent thrombosis (RR 0.92; 95% CI 0.35–2.38), in-hospital mortality (RR 1.38; 95% CI 0.72–2.65), and major bleeding (RR 0.89; 95% CI 0.33–2.40) between patients receiving clopidogrel versus those receiving newer agents.

Conclusions

This meta-analysis showed no difference between clopidogrel and newer antiplatelet agents in the incidence of stent thrombosis or in-hospital mortality for PCI in cases of TH. Further randomized studies are needed to explore the optimal dual antiplatelet treatment in TH.

Electronic supplementary material

The online version of this article (10.1007/s40119-018-0118-x) contains supplementary material, which is available to authorized users.

Impaired biological response to aspirin in therapeutic hypothermia comatose patients resuscitated from out-of-hospital cardiac arrest

AIM OF THE STUDY

Acute coronary syndrome is one of the main causes of out-of-hospital cardiac arrest (OHCA). OHCA patients are particularly exposed to high platelet reactivity (HPR) under aspirin (ASA) treatment. The aim was to evaluate HPR-ASA in therapeutic hypothermia comatose patients resuscitated from OHCA.

METHODS AND RESULTS

Twenty-two consecutive patients with OHCA of cardiac origin were prospectively included after therapeutic hypothermia and randomized to receive ASA 100mg per day, either intravenously (n=13) or orally via a gastric tube (n=9). ADP inhibitors (prasugrel or, if contra-indicated, clopidogrel) were administered in the event of angioplasty. HPR-ASA was assessed by light transmission aggregometry (LTA) with arachidonic acid (AA) and by the PFA-100(®) system with collagen/epinephrine. Clinical, biological and angiographic characteristics were similar in both groups. Using LTA-AA, maximum aggregation intensity was significantly lower in the intravenous group compared to the oral group (15% vs. 29%, respectively; p=0.04). Overall, 10 patients (45%) had HPR-ASA (38% intravenously vs 56% orally; p=0.7). Similarly, closure time was significantly increased in the IV group (277s vs. 155s, respectively; p=0.04).

CONCLUSION

This study suggests that impaired response to both intravenous and oral aspirin is frequent in comatose patients resuscitated from OHCA.

Efficacy and safety of vorapaxar for the prevention of adverse cardiac events in patients with coronary artery disease: a meta-analysis

BACKGROUND

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Vorapaxar, a protease-activated receptor-1 (PAR-1) antagonist, is a novel antiplatelet agent that may provide us a new way in antithrombotic therapy. Several studies had been conducted to evaluate the efficacy of vorapaxar in the treatment of CAD, but the results were inconsistent. Here a meta-analysis was made to assess the efficacy and safety of vorapaxar in reducing adverse cardiac events in patients with CAD.

METHODS

A comprehensive literature search was conducted. The primary efficacy endpoint was the major adverse cardiac events, which was defined as a composite of cardiovascular death, myocardial infarction (MI), stroke, urgent coronary revascularization, or recurrent ischemia with rehospitalization. The primary safety endpoint was the composite of major or minor bleeding events. Pooled effects were measured by odds ratios (ORs) with 95% confidence intervals (CIs). A random-effect or fixed model was used in this meta-analysis.

RESULTS

Totally, 31,388 patients from four randomized controlled trials (RCTs) were included in this meta-analysis. Patients who took vorapaxar combined with standard dual anti-platelet therapy (aspirin and thienopyridine) showed a lower incidence in major adverse cardiac events (OR, 0.86, 95% CI: 0.75-0.99, P=0.03), MI (OR, 0.79, 95% CI: 0.67-0.95, P=0.01) and ischemic stroke (OR, 0.72, 95% CI: 0.58-0.89, P=0.003) than those who only took placebo instead. But there was no significant reduction in cardiovascular death (OR, 0.95, 95% CI: 0.82-1.09, P=0.45). Nevertheless, the vorapaxar group were associated with a higher risk of bleeding events (P<0.001).

CONCLUSIONS

The result of this meta-analysis indicated that adding vorapaxar to the standard dual anti-platelet therapy may be efficient in reducing the incidence of major adverse cardiac events at the cost of increasing risk of bleeding events.

Efficacy of enteral ticagrelor in hypothermic patients after out-of-hospital cardiac arrest

Introduction

Delivery of crushed ticagrelor via a nasogastric tube is a widely spread off-label use in unconscious patients following out-of-hospital cardiac arrest (OHCA). Notwithstanding the importance of a potent dual antiplatelet therapy in these patients, the efficacy of crushed ticagrelor after OHCA has not been established yet.

Methods

In a prospective, single-center, observational trial, 38 consecutive MI patients after OHCA were included. 27 patients (71.1 %) underwent mild induced hypothermia. The primary outcome was platelet inhibition at 24h measured by impedance aggregometry.

Results

There was sufficient platelet inhibition in most patients after OHCA. In all hypothermic patients, there was an adequate platelet inhibition by ticagrelor at 24 h (p < 0.001). 15 patients (39.5 %) had significant gastroesophageal reflux and one patient with significant reflux had inadequate platelet inhibition at 24 h. There were no stent thrombosis or recurrent atherothrombotic events in these patients.

Conclusion

Administration of crushed ticagrelor via a nasogastric tube reliably inhibited platelet function in vitro and in vivo regardless of the presence of hypothermia in MI patients. Thus, platelet inhibition can be reliably achieved in MI patients during neuroprotective hypothermia following OHCA.

The impact of switching P2Y12 receptor inhibitor therapy during index hospitalization: a systematic review

PURPOSE

With the availability of novel P2Y12 receptor inhibitors, patients presenting with acute coronary syndrome (ACS) may receive more than one type of this drug during index hospitalization. We sought to determine the effect of switching from clopidogrel to a novel P2Y12 receptor inhibitor on the occurrence of major adverse cardiovascular events (MACE) and bleeding.

METHODS

We conducted a literature search on SCOPUS for English language entries until 7 March 2015. Out of 188 citations, seven studies encompassing 16,431 patients were selected for analysis of (i) switching to a novel P2Y12 agent (switching group) versus continued clopidogrel or (ii) switching to a novel P2Y12 agent (switching group) versus upfront novel agent initiation during index hospitalization

RESULTS

MACE was significantly lower in the switching group (odds ratio (OR) 0.77, 95 % confidence interval (CI) 0.63-0.96, p = 0.02), whereas bleeding was higher (OR 1.55, 1.29-1.85, p < 0.01) compared with continued clopidogrel. Conversely, MACE was similar with switching to a novel agent and upfront novel therapy initiation (OR 1.01, 95 % CI 0.8-1.29, p = 0.90), but bleeding was higher in the switching group (OR 1.24, 95 % CI 1.03-1.48, p = 0.02).

CONCLUSIONS

The current study suggests that switching to a novel P2Y12 agent in patients with ACS and/or patients undergoing coronary stenting is more efficacious than continuing clopidogrel. In this cohort, switching to a novel agent did not result in worse ischemic outcomes than upfront initiation of novel therapies. However, switching was associated with greater bleeding compared with both continued clopidogrel as well as upfront use of novel P2Y12 agents.