Life-threatening complete atrioventricular block associated with ticagrelor therapy

Progress in the clinical effects and adverse reactions of ticagrelor

BACKGROUND

Ticagrelor is a novel receptor antagonist that selectively binds to the P2Y12 receptor, thereby inhibiting adenosine diphosphate (ADP)-mediated platelet aggregation. Compared to clopidogrel, ticagrelor has the advantages of a fast onset, potent effects, and a reversible platelet inhibition function, which make this drug clinically suitable for treating acute coronary syndrome (ACS), especially acute ST-segment elevation myocardial infarction (STEMI).

OBJECTIVE

This review was performed to determine the basic characteristics, clinical effects, and adverse reactions of ticagrelor.

METHODS

Relevant trials and reports were obtained from the MEDLINE, Embase, and Cochrane Library databases.

RESULTS

Ticagrelor is rapidly absorbed by the body after oral administration, exhibits inherent activity without requiring metabolic activation, and binds reversibly to the P2Y12 receptor. Ticagrelor has been recommended in ACS treatment guidelines worldwide due to its advantageous pharmacological properties and significant clinical benefits. Ticagrelor inhibits platelet aggregation, inhibits inflammatory response, enhances adenosine function, and has cardioprotective effects. However, ticagrelor also causes adverse reactions such as bleeding tendency, dyspnea, ventricular pause, gout, kidney damage, and thrombotic thrombocytopenic purpura in clinical treatment. Therefore, it is necessary to pay attention to risk assessments when using ticagrelor.

CONCLUSION

Ticagrelor is a promising drug for the effective treatment of ACS. When using ticagrelor, individualized treatment should be provided based on the specific conditions of the patients to avoid serious adverse events.

Ticagrelor Can Regulate the Ion Channel Characteristics of Superior Cervical Ganglion Neurons after Myocardial Infarction

BACKGROUND

The superior cervical ganglion (SCG) plays a key role in cardiovascular diseases. The aim of this study was to determine the changes in the ion channel characteristics of the SCG following myocardial infarction (MI) and the role of pretreatment with the P2Y12 receptor antagonist ticagrelor (TIC).

METHODS

A total of 18 male rabbits were randomly divided into a control group, MI group, and P2Y12 receptor antagonist (TIC) group (abbreviated as the TIC group). Rabbit MI was performed via two abdominal subcutaneous injections of 150 mg·kg-1·d-1 of isoproterenol (ISO) with an interval of 24 h. TIC pretreatment at 20 mg·kg-1·d-1 was administered via gavage for two consecutive days. The cardiac function of each group was evaluated with echocardiography. ADP receptor P2Y12 expressions in SCGs were determined using RT-PCR and immunofluorescence staining. Ion channel characteristics of SCG neurons were measured using a whole-cell patch clamp. Intracellular calcium concentrations for SCG neurons were measured using confocal microscopy.

RESULTS

Cardiac function was reduced in the rabbits of the MI group, the sympathetic nerve activity of SCGs was increased, and the current amplitude of the neuron ion channel was increased. MI led to alterations in the activation and inactivation characteristics of INa channels accompanied by increased expression of P2Y12 in SCGs. Most of these abnormalities were prevented by TIC pretreatment in the TIC group.

CONCLUSIONS

TIC pretreatment could attenuate the increase in P2Y12 expression in SCGs and the changes to the ion channel characteristics of SCG neurons after MI. This may be the mechanism underlying the cardiac protective effects of TIC.

Adverse reaction signals mining and hemorrhagic signals comparison of ticagrelor and clopidogrel: A pharmacovigilance study based on FAERS

Background: Ticagrelor and clopidogrel are commonly used antiplatelet agents, and we conducted a pharmacovigilance analysis using the Food and Drug Administration Adverse Event Reporting System (FAERS) to provide a reference for safe and reasonable clinical use.

Methods: Data were collected in FAERS from 2012 Q1 to 2022 Q2 for data cleaning. We used system organ classes (SOCs) and prefer terms (PTs) from the Medical Dictionary of Regulatory Activity (MedDRA version 25.1). Adverse event reports were retrieved at the PT level. Adverse reaction (ADR) signals of ticagrelor and clopidogrel were mined by calculating reporting odds ratios (ROR), proportional reporting ratios (PRR), information component (IC) and empirical Bayesian geometric mean (EBGM). After that, further analysis of the hemorrhagic signals and their clinical information were performed.

Results: The number of ADR reports where the primary suspect (PS) drugs were 15,133 for ticagrelor and 23,860 for clopidogrel. Significant ADR signals were identified by the SOC analysis for ticagrelor including cardiac disorders (ROR 4.87, PRR 4.46), respiratory disorders (ROR 2.45, PRR 2.28), and vascular disorders (ROR 2.22, PRR 2.16). Clopidogrel included blood disorders (ROR 2.86, PRR 2.77), vascular disorders (ROR 2.71, PRR 2.61), and cardiac disorders (ROR 2.29, PRR 2.22). At the PT level, the more frequent ADR signals for ticagrelor were dyspnoea, contusion, and haemorrhage, while clopidogrel were gastrointestinal haemorrhage, anaemia, and drug interaction. The hemorrhagic signals of both were mainly focused on the SOC level of gastrointestinal disorders, injury disorders and vascular disorders and nervous system disorders. The death and life-threatening rate of ticagrelor was 7.76 percentage higher than that of clopidogrel.

Conclusion: Clinicians need to pay attention to not only common ADRs but also be alert to new ADR signals when choosing to use ticagrelor and clopidogrel. This study provides a reference for the reasonable and safe clinical use of ticagrelor and clopidogrel.

Heart Block Caused by Ticagrelor Use in a Patient Who Underwent Adenosine Diastolic Fractional Reserve Assessment: A Case Report

Ticagrelor is a direct and rapid-acting antagonist of the P2Y12-adenosine diphosphate receptor found on platelets. The drug is recommended as a first-line antiplatelet agent in patients with acute coronary syndromes, as evidenced in its superiority compared to clopidogrel according to the Platelet Inhibition and Patient Outcomes study. Specifically, the mechanism of action has been proven to show higher inhibition and less variability in its action on P2Y12 receptors compared to clopidogrel. Additionally, ticagrelor inhibits the equilibrative nucleoside transporter 1 adenosine transporter protein leading to an increased concentration of adenosine in the blood, particularly at sites of ischemia. This effect increases the biological efficacy of ticagrelor in terms of cardioprotection, anticoagulation effects, and anti-inflammatory effects. However, the effects are also thought to be responsible for some of the adverse pharmacological effects reported with ticagrelor, such as bradycardia and ventricular pauses > 3 seconds. Herein, we report a case of recurrent sinus arrest and ventricular asystole in a patient pre-treated with ticagrelor and subsequent physiological assessment of a coronary lesion with fractional flow reserve using intravenous adenosine infusion.

A rare but serious complication of ticagrelor therapy: a case report

Background

Ticagrelor is a widely used P2Y12 inhibitor and represents a fundamental therapeutic agent in acute coronary syndrome treatment and selected post-percutaneous coronary intervention (PCI) cases. Dyspnoea and bradycardia are the most common side effects but the latter has been reported to be of trivial clinical significance

Case summary

A 51-year-old gentleman underwent PCI to left anterior descending and obtuse marginal for unstable angina receiving a loading dose of ticagrelor (180 mg). During hospital stay, whilst on telemetry monitoring, a 16 s long, symptomatic, asystolic ventricular standstill was recorded prompting ticagrelor interruption and a switch to prasugrel.

Discussion

Despite ventricular pauses have been reported in dedicated analyses of Phase III trials, no apparent clinical consequences were documented. However, several reports have shown that significant brady-arrhythmic events might be linked to ticagrelor administration presenting both as sino-atrial and atrio-ventricular conduction disturbances. We report a case of asystole occurring 36 h after the administration of a loading dose.

Premature Ticagrelor Discontinuation in Secondary Prevention of Atherosclerotic CVD: JACC Review Topic of the Week

Ticagrelor is a cornerstone of modern antithrombotic therapy alongside aspirin in patients with acute coronary syndrome and after percutaneous coronary intervention. Adverse effects such as bleeding and dyspnea have been associated with premature ticagrelor discontinuation, which may limit any potential advantage of ticagrelor over clopidogrel. The randomized trials of ticagrelor captured adverse events, offering the opportunity to more precisely quantify these effects across studies. Therefore, a meta-analysis of 4 randomized clinical trials of ticagrelor conducted between January 2007 and June 2017 was performed to quantify the incidence and causes of premature ticagrelor discontinuation. Among 66,870 patients followed for a median 18 months, premature ticagrelor discontinuation was seen in 25%; bleeding was the most common cause of discontinuation followed by dyspnea. Versus the comparators, the relative risk of dyspnea-related discontinuation during follow-up was 6.4-fold higher, the relative risk of bleeding was 3.2-fold higher, and the relative risk of discontinuation due to any adverse event was 59% higher for patients receiving ticagrelor. Understanding these potential barriers to adherence to ticagrelor is crucial for informed patient-physician decision making and can inform future efforts to improve ticagrelor adherence. This review discusses the incidence, causes, and biological mechanisms of ticagrelor-related adverse effects and offers strategies to improve adherence to ticagrelor.

Comparison of atrial fibrillation predictors in patients with acute coronary syndrome using ticagrelor or clopidogrel

Background/aim

Ticagrelor is a drug widely used in patients with acute coronary syndromes (ACS) that specifically increases the plasma level of adenosine, which is likely to cause atrial fibrillation (AF). Therefore, in this study we aimed to investigate the electrocardiographic and echocardiographic predictors of AF development after P2Y12 receptor antagonists in ACS patients.

Materials and methods

This cross-sectional study included 831 patients with ACS (486 [58.5%] with ST elevated myocardial infarction [STEMI] and 345 [41.5%] with non-ST elevated myocardial infarction [NSTEMI]). Patients were divided into ticagrelor (n = 410) and clopidogrel (n = 421) groups. P wave properties including P wave dispersion and atrial electromechanical conduction properties were measured as AF predictors with surface ECG and tissue Doppler imaging.

Results

Baseline characteristics such as age, sex, heart rate, blood pressure, and laboratory parameters were almost the same in the ticagrelor and clopidogrel groups. The statistical analysis showed no significant difference in P wave dispersion (PWD) between ticagrelor and clopidogrel groups (40.98 ± 12 ms versus 40.06 ± 12 ms, P = 0.304). Subgroups analysis according to ACS types also showed no significant difference in PWD (NSTEMI: 41.16 ± 13.8 ms versus 40.76 ± 13.55 ms, P = 0.799; STEMI: 40.9 ± 12.62 ms versus 39.19 ± 11.18 ms, P = 0.132). In addition, we did not find significant difference in atrial electromechanical delay (EMD) with tissue Doppler imaging (interatrial EMD 24.11 ± 3.06 ms versus 24.46 ± 3.23 ms, P = 0.279).

Conclusion

In conclusion, we did not find any difference in detailed electrocardiographic and echocardiographic parameters as AF predictors between ticagrelor and clopidogrel groups in patients with ACS

Ticagrelor-associated ventricular pauses: a case report and literature review

Background

Case summary

Discussion

Effects of prasugrel on membrane potential and contractile activity of rat ventricular myocytes

BACKGROUND

Though prasugrel is one of the important P2Y12 inhibitors currently in use for antiplatelet therapy, its potential effects on contractility and electrical activity of ventricular myocytes have not yet been investigated. Hence this study was designed to study the impact of prasugrel on contractile function and membrane potential of isolated ventricular myocytes.

METHODS

Freshly isolated rat ventricular myocytes were used in this study. Myocyte contraction was measured during electrical stimulation of cardiomyocytes and the action potential (AP) recordings were obtained with current clamp mode of the patch-clamp amplifier.

RESULTS

AP duration and fractional shortening of ventricular myocytes did not show any change with the administration of 1μM of prasugrel. However, remarkable depolarization of resting membrane potential followed by apparent fibrillation episodes was detected in the cardiomyocytes. Similar events were observed in the contractile activity of myocytes during field stimulation. Also, a higher concentration of prasugrel (10μM) elicited repeated fibrillations, which disappeared after washout or nitric oxide synthase (NOS) inhibition with L-NAME. In contrast, the same concentration of ticagrelor, another P2Y12 inhibitor did not induce fibrillation events though it decreased the contractility of ventricular myocytes significantly. The perfusion of ventricular myocytes with L-NAME did not alter the negative inotropic effect of ticagrelor.

CONCLUSIONS

Prasugrel, a widely used antithrombotic agent, may induce depolarization in the membrane potential of myocytes as well as fibrillation via NO mediated pathway.

Ticagrelor - toward more efficient platelet inhibition and beyond

Novel antiplatelet drugs, including ticagrelor, are being successively introduced into the therapy of atherothrombotic conditions due to their superiority over a standard combination of clopidogrel with acetylsalicylic acid in patients with acute coronary syndromes (ACS). A P2Y12 receptor antagonist, ticagrelor, is unique among antiplatelet drugs, because ticagrelor inhibits the platelet P2Y12 receptor in a reversible manner, and because it demonstrates a wide palette of advantageous pleiotropic effects associated with the increased concentration of adenosine. The pleiotropic effects of ticagrelor comprise cardioprotection, restoration of the myocardium after an ischemic event, promotion of the release of anticoagulative factors and, eventually, anti-inflammatory effects. Beyond the advantageous effects, the increased concentration of adenosine is responsible for some of ticagrelor's adverse effects, including dyspnea and bradycardia. Large-scale clinical trials demonstrated that both standard 12-month therapy and long-term use of ticagrelor reduce the risk of cardiovascular events in patients with ACS, but at the expense of a higher risk of major bleeding. Further trials focused on the use of ticagrelor in conditions other than ACS, including ischemic stroke, peripheral artery disease and status after coronary artery bypass grafting. The results of these trials suggest comparable efficacy and safety of ticagrelor and clopidogrel in extra-coronary indications, but firm conclusions are anticipated from currently ongoing studies. Here, we summarize current evidence on the superiority of ticagrelor over other P2Y12 antagonists in ACS, discuss the mechanism underlying the drug-drug interactions and pleiotropic effects of ticagrelor, and present future perspectives of non-coronary indications for ticagrelor.

Ticagrelor-Associated Conduction Disorder: A Case Report and Review of the Literature

A 47-year-old female presented to emergency clinic due to non-ST-elevation myocardial infarction (NSTEMI). After receiving acetylsalicylic acid, a loading dose of ticagrelor 180 mg and intravenous unfractionated heparin, she underwent successful placement of drug eluting stent on the distal part of non-dominant left circumflex artery. The patient had no pre-existing atrioventricular (AV) block and did not use AV blocking agent. Approximately 10 h after taking a loading dose of ticagrelor, baseline normal rhythm degenerated to the first and then complete AV block, with mild dizziness. Following cessation of ticagrelor, cardiac rhythm returned to normal level within 2 days. The close monitoring of patients after starting ticagrelor is imperative, so ticagrelor may result in advanced conduction disorders. Here, we report a patient who developed various types of AV block associated with the ticagrelor taken during successful percutaneous coronary intervention for NSTEMI. We also reviewed the literature on the association between ticagrelor use and conduction abnormalities.

Ticagrelor therapy and atrioventricular block: Do we need to worry?

Ticagrelor is a potent, direct P2Y12 antagonist with rapid onset of action and intense platelet inhibition, indicated in patients with acute coronary syndromes (ACS). This drug is usually well tolerated, but some patients experience serious adverse effects: Major bleeding; gastrointestinal disturbances; dyspnoea; ventricular pauses > 3 s. Given the unexpected high incidence of bradyarrhythmias, a PLATO substudy monitored this side effect, showing that ticagrelor was associated with an increase in the rate of sinus bradycardia and sinus arrest compared to clopidogrel. This side effect was usually transient, asymptomatic and not associated with higher incidence of severe atrioventricular (AV) block or pacemaker needs. A panel of experts from Food and Drug Administration did not consider bradyarrhythmias a serious problem in clinical practice and, accordingly, current labeling of the drug does not give any precaution or contraindication regarding this issue. However, recently some articles have described ACS patients with high-degree, life-threatening, AV block requiring drug discontinuation and, in some cases, pacemaker implantation. In this paper, we describe and discuss five published case reports of severe AV block following ticagrelor therapy and two other cases managed in our Hospital. The analysis of literature suggests that, although rarely, ticagrelor can be associated with life-threatening AV block. Caution and careful monitoring are required especially in patients with already compromised conduction system and/or treated with AV blocking agents. Future studies, with long-term rhythm monitoring, would help to define the outcome of patients at higher risk of developing this complication.

Ticagrelor Associated Heart Block: The Need for Close and Continued Monitoring

Ticagrelor is an antiplatelet agent prescribed to prevent the development of adverse cardiac events after acute coronary syndrome (ACS). According to the PLATO trial, ticagrelor is associated with ventricular pauses in the first week of treatment; however, these episodes were felt to be asymptomatic and nonfatal to the patient. We present a case of ticagrelor related second-degree type II heart block causing severe dizziness and diaphoresis that resolved after discontinuation of the medication.

Successful Reversal of Bradycardia and Dyspnea With Aminophylline After Ticagrelor Load

A 69-year-old male underwent elective percutaneous coronary intervention requiring placement of a drug-eluting stent to the first obtuse marginal artery. Four hours following the administration of a ticagrelor loading dose, he developed dyspnea and sinus pauses. Aminophylline was administered and resulted in immediate and sustained symptom resolution. Ticagrelor has been associated with dyspnea and bradyarrhythmias, both attributed to increased adenosine exposure. Ticagrelor inhibits reuptake of intracellular adenosine. Adenosine antagonists aminophylline and theophylline have been utilized to reverse the effects of adenosine and may relieve adenosine-mediated adverse effects induced by ticagrelor therapy. Aminophylline may be considered for reversal of dyspnea and bradyarrhythmia associated with ticagrelor therapy through alterations in adenosine exposure.