Dabigatran Dual Therapy Versus Warfarin Triple Therapy Post–PCI in Patients With Atrial Fibrillation and Diabetes

CYP2C19 Polymorphism in Ischemic Heart Disease Patients Taking Clopidogrel After Percutaneous Coronary Intervention in Egypt

BACKGROUND

Cardiovascular diseases (CVDs) are considered a leading cause of death worldwide. Allelic variation in the CYP2C19 gene leads to a dysfunctional enzyme, and patients with this loss-of-function allele will have an impaired clopidogrel metabolism, which eventually results in major adverse cardiovascular events (MACE). Ischemic heart disease patients (n = 102) who underwent percutaneous cardiac intervention (PCI) followed by clopidogrel were enrolled in the present study.

METHODS

The genetic variations in the CYP2C19 gene were identified using the TaqMan chemistry-based qPCR technique. Patients were followed up for 1 year to monitor MACE, and the correlations between the allelic variations in CYP2C19 and MACE were recorded.

RESULTS

During the follow-up, we reported 64 patients without MACE (29 with unstable angina (UA), 8 with myocadiac infarction (MI), 1 patient with non-STEMI, and 1 patient with ischemic dilated cardiomyopathy (IDC)). Genotyping of CYP2C19 in the patients who underwent PCI and were treated with clopidogrel revealed that 50 patients (49%) were normal metabolizers for clopidogrel with genotype CYP2C19*1/*1 and 52 patients (51%) were abnormal metabolizers, with genotypes CYP2C19*1/*2 (n = 15), CYP2C19*1/*3 (n = 1), CYP2C19*1/*17 (n = 35), and CYP2C19*2/*17 (n = 1). Demographic data indicated that age and residency were significantly associated with abnormal clopidogrel metabolism. Moreover, diabetes, hypertension, and cigarette smoking were significantly associated with the abnormal metabolism of clopidogrel. These data shed light on the inter-ethnic variation in metabolizing clopidogrel based on the CYP2C19 allelic distribution.

CONCLUSION

This study, along with other studies that address genotype variation of clopidogrel-metabolizing enzymes, might pave the way for further understanding of the pharmacogenetic background of CVD-related drugs.

Reporting quality of randomized controlled trials evaluating non-vitamin K oral anticoagulants in atrial fibrillation: a systematic review

BACKGROUND

Randomized controlled trials (RCTs) are subject to bias if they lack methodological quality. Furthermore, optimal and transparent reporting of RCT findings aids their critical appraisal and interpretation. This study aimed to comprehensively evaluate the report quality of RCTs of non-vitamin K oral anticoagulants (NOACs) for the treatment of atrial fibrillation (AF) and to analyze the factors influencing the quality.

METHODS

By searching PubMed, Embase, Web of Science, and Cochrane Library databases RCTs published from inception to 2022 evaluating the efficacy of NOACs on AF were collected. By using the 2010 Consolidated Standards for Reporting Tests (CONSORT) statement, the overall quality of each report was assessed.

RESULTS

Sixty-two RCTs were retrieved in this study. The median of overall quality score in 2010 was 14 (range: 8.5-20). The extent of compliance with the Consolidated Standards of Reporting Trials reporting guideline differed substantially across items: 9 items were reported adequately (more than 90%), and 3 were reported adequately in less than 10% of trials. Multivariate linear regression analysis showed that the higher reporting scores were associated with higher journal impact factor (P = 0.01), international collaboration (P < 0.01), and Sources of trial funding (P = 0.02).

CONCLUSIONS

Although a large number of randomized controlled trials of NOACs for the treatment of AF were published after the CONSORT statement in 2010, the overall quality is still not satisfactory, thus weakening their potential utility and may mislead clinical decisions. This survey provides the first hint for researchers conducting trials of NOACs for AF to improve the quality of reports and to actively apply the CONSORT statement.

Antithrombotic Management in AF Patients Following Percutaneous Coronary Intervention: A European Perspective

AF is a highly prevalent disease, often requiring long-term oral anticoagulation to prevent stroke or systemic embolism. Coronary artery disease, which is common among AF patients, is often referred for myocardial revascularisation by percutaneous coronary intervention (PCI), which requires dual antiplatelet therapy to minimise the risk of stent-related complications. The overlap of AF and PCI is a clinical conundrum, especially in the early post-procedural period, when both long-term oral anticoagulation and dual antiplatelet therapy are theoretically indicated as a triple antithrombotic therapy. However, stacking drugs is not a desirable option because of the increased bleeding risk. Several strategies have been investigated to mitigate this concern, including shortening triple antithrombotic therapy duration and switching to a dual antithrombotic regimen. This review analyses the mechanisms underlying thrombotic complications in AF-PCI, summarises evidence surrounding antithrombotic therapy regimens and reports and comments on the latest European guidelines.

Managing thrombotic risk in patients with diabetes

It is well known that diabetes is a prominent risk factor for cardiovascular (CV) events. The level of CV risk depends on the type and duration of diabetes, age and additional co-morbidities. Diabetes is an independent risk factor for atrial fibrillation (AF) and is frequently observed in patients with AF, which further increases their risk of stroke associated with this cardiac arrhythmia. Nearly one third of patients with diabetes globally have CV disease (CVD). Additionally, co-morbid AF and coronary artery disease are more frequently observed in patients with diabetes than the general population, further increasing the already high CV risk of these patients. To protect against thromboembolic events in patients with diabetes and AF or established CVD, guidelines recommend optimal CV risk factor control, including oral anticoagulation treatment. However, patients with diabetes exist in a prothrombotic and inflammatory state. Greater clinical benefit may therefore be seen with the use of stronger antithrombotic agents or innovative drug combinations in high-risk patients with diabetes, such as those who have concomitant AF or established CVD. In this review, we discuss CV risk management strategies in patients with diabetes and concomitant vascular disease, stroke prevention regimens in patients with diabetes and AF and how worsening renal function in these patients may complicate these approaches. Accumulating evidence from clinical trials and real-world evidence show a benefit to the administration of non-vitamin K antagonist oral anticoagulants for stroke prevention in patients with diabetes and AF.

A novel risk score to identify the need for triple antithrombotic therapy in patients with atrial fibrillation undergoing percutaneous coronary intervention: a post hoc analysis of the RE-DUAL PCI trial

BACKGROUND

Current guidelines recommend treating atrial fibrillation (AF) patients who undergo percutaneous coronary intervention (PCI) with triple antithrombotic therapy (TAT) for up to one month in patients at high thrombotic risk. It is unclear how to select these high-risk patients.

AIMS

The aim of this study was to identify patients at high thrombotic risk who might benefit from TAT over double antithrombotic therapy (DAT).

METHODS

This study was a post hoc subanalysis of the RE-DUAL PCI trial. A Cox proportional hazards model was built by stepwise selection of plausible predictor variables for a composite ischaemic endpoint, defined as cardiovascular death, myocardial infarction (MI), stent thrombosis (ST) or ischaemic stroke. The effect of TAT versus DAT was calculated for those patients with the highest proportion of predicted thrombotic risk. A simplified risk score was constructed based on beta-coefficients.

RESULTS

For 209 patients (7.7%) the composite ischaemic endpoint occurred during the first year. The simplified risk score contained six variables. In patients with a score ≥5 (n=154, 5.7%), a significant reduction in the composite of MI and ST was observed with TAT versus DAT (6.3% vs 21.0%, p=0.041), without a penalty in terms of bleeding. In patients at low thrombotic risk, a significant increase in bleeding was observed without a reduction of ischaemic events.

CONCLUSIONS

Our findings support the use of DAT in the majority of patients. A small subgroup of patients might benefit from TAT and we propose a novel clinical risk score to select these patients.

Medical therapies for prevention of cardiovascular and renal events in patients with atrial fibrillation and diabetes mellitus

Atrial fibrillation (AF), type 2 diabetes mellitus (DM), and chronic kidney disease (CKD) are three global epidemics with significant effects on morbidity and mortality. Diabetes is a risk factor for AF, and a risk factor for thromboembolism, comorbidity, and mortality when AF is present. The pathophysiology of diabetes-related AF and interrelationships with cardiovascular events and renal events is not fully understood but is in part related to structural, electrical, electromechanical, and autonomic remodelling. The current practice guidelines offer limited recommendations on the management of patients with AF (or risk of AF) and diabetes with its own heterogeneity for the prevention of cardiovascular and renal events. This document discusses possible clinical approaches for these patients. In the last decade, there have been major improvements for the prevention of stroke in AF patients with direct oral anticoagulants, which are preferable to vitamin K antagonists for stroke prevention in DM. Because of the increased risk rate for several cardiovascular adverse events in diabetic patients, a similar relative risk reduction generally translates into greater absolute risk reduction in the diabetic population. Recent trials with non-insulin diabetes drugs using glucagon-like peptide-1 agonists and sodium-glucose cotransporter-2 inhibitors showed a significant reduction for the risk of major adverse cardiovascular events in patients with type 2 DM. Sodium-glucose cotransporter-2 inhibitors also showed a large reduction in hospitalization for heart failure and renal events, which need to be more completely evaluated in patients with AF. Mechanisms, risks, and optimal management of AF patients with DM who have or are under risk of developing heart failure or CKD are also discussed in this document. The benefits of medical therapies for these patients still need to be put into perspective, and gaps in evidence on some of these issues are likely to be addressed in future years.

The role of triple antithrombotic therapy in patients with atrial fibrillation undergoing percutaneous coronary intervention

Dual antiplatelet therapy (DAPT) with aspirin plus clopidogrel forms the backbone of secondary prevention in patients with acute coronary syndromes (ACS) or who undergo percutaneous coronary intervention (PCI), but in patients with atrial fibrillation (AF), oral anticoagulation (OAC) is superior to antiplatelet therapy for the prevention of stroke and systemic embolism. Patients with AF who undergo PCI or have an ACS event therefore have an indication for both OAC and DAPT, so-called triple antithrombotic therapy. However, observational analyses have shown that the annual rate of major bleeding on triple therapy exceeds 10%. For this reason, five major randomized clinical trials have compared double antithrombotic therapy with OAC and a P2Y₁₂ inhibitor versus triple therapy in patients with AF who underwent PCI or had an ACS event. Each of the trials showed that double antithrombotic therapy reduced the rate of major and clinically relevant non-major bleeding compared with triple therapy and was non-inferior for prevention of ischemic events, including cardiovascular death, myocardial infarction, or stroke. In the one trial that directly compared warfarin with a non-vitamin K antagonist oral anticoagulant (NOAC), apixaban reduced the rate of major or clinically relevant non-major bleeding compared with warfarin and was non-inferior with respect to prevention of ischemic events. As a result of these trials, consensus guidelines recommend that patients with AF who undergo PCI or have an ACS event should be treated with triple antithrombotic therapy (OAC + P2Y₁₂ inhibitor + aspirin) for 7 days or less, followed by double antithrombotic therapy (OAC + P2Y₁₂ inhibitor) for 6 to 12 months.

Role and Timing of Aspirin Therapy Following PCI in Patients With Atrial Fibrillation

In patients with atrial fibrillation who undergo percutaneous coronary intervention (PCI), both anticoagulation and dual antiplatelet therapy (aspirin plus a P2Y₁₂ inhibitor) are indicated. However, this "triple" antithrombotic therapy is associated with high rates of bleeding. Finding the right balance of reducing ischemic risk and protecting coronary stents from restenosis while not increasing bleeding risk is difficult. In the past 5 years, 6 randomized clinical trials have shown the benefit of dropping aspirin from the triple therapy regimen to create "dual" therapy (oral anticoagulants and P2Y₁₂ inhibitors alone) with reductions in bleeding without a significant increase in ischemic events. Because of small trends toward higher risk of stent thrombosis, especially in higher risk patients with acute coronary syndromes, current recommendations call for dual therapy as the "default" regimen, but that risk stratification be used to help inform the decision on potentially using a brief period of triple therapy in selected high ischemic risk patients. For long-term therapy (after one year post-PCI), recent studies have found oral anticoagulation alone without any antiplatelet therapy has a favorable benefit risk ratio. Thus, while dropping aspirin at varying times post-PCI has become an attractive strategy in many patient groups, careful patient selection and individualized assessment of the risk:benefit balance is warranted.

High-Dose Dabigatran Is an Effective Anticoagulant for Simulated Cardiopulmonary Bypass Using Human Blood

BACKGROUND

Currently no ideal alternative exists for heparin for cardiopulmonary bypass (CPB). Dabigatran is a direct thrombin inhibitor for which a reversal agent exists. The primary end point of the study was to explore whether Dabigatran was an effective anticoagulant for 120 minutes of simulated CPB.

METHODS

The study was designed in 2 sequential steps. Throughout, human blood from healthy donors was used for each experimental step. Initially, increasing concentrations of Dabigatran were added to aliquots of fresh whole blood, and the anticoagulant effect measured using kaolin/tissue factor-activated thromboelastography (rapidTEG). The dynamics of all thromboelastography (TEG) measurements were studied with repeated measures analysis of variance (ANOVA). Based on these data, aliquots of blood were treated with high-concentration Dabigatran and placed in a Chandler loop as a simple ex vivo bypass model to assess whether Dabigatran had sufficient anticoagulant effects to maintain blood fluidity for 2 hours of continuous contact with the artificial surface of the PVC tubing. Idarucizumab, humanized monoclonal antibody fragment, was used to verify the reversibility of Dabigatran effects. Finally, 3 doses of Dabigatran were tested in a simulated CPB setup using a heart-lung machine and a commercially available bypass circuit with an arteriovenous (A-V) loop. The primary outcome was the successful completion of 120 minutes of simulated CPB with dabigatran anticoagulation, defined as lack of visible thrombus. Thromboelastographic reaction (R) time was measured repeatedly in each bypass simulation, and the circuits were continuously observed for clot. Scanning Electron Microscopy (SEM) was used to visualize fibrin formation in the filters meshes during CPB.

RESULTS

In in vitro blood samples, Dabigatran prolonged R time and reduced the dynamics of clot propagation (as measured by speed of clot formation [Angle], maximum rate of thrombus generation [MRTG], and time to maximum rate of thrombus generation [TMRTG]) in a dose-dependent manner. In the Chandler Loop, high doses of Dabigatran prevented clot formation for 120 minutes, but only at doses higher than expected. Idarucizumab decreased R time and reversed anticoagulation in both in vitro and Chandler Loops settings. In the A-V loop bypass simulation, Dabigatran prevented gross thrombus generation for 120 minutes of simulated CPB.

CONCLUSIONS

Using sequential experimental approaches, we showed that direct thrombin inhibitor Dabigatran in high doses maintained anticoagulation of blood for simulated CPB. Idarucizumab reduced time for clot formation reversing the anticoagulation action of Dabigatran.

Non-Vitamin K Antagonist Oral Anticoagulants and the Gastrointestinal Bleeding Risk in Real-World Studies

In the present study, we aimed to provide evidence from high-quality real world studies for a comprehensive and rigorous analysis on the gastrointestinal bleeding (GIB) risk for non-vitamin K antagonist oral anticoagulants (NOACs). We performed a systematic search of MEDLINE, EMBASE and PUBMED, and of 286 records screened, we included data from 11 high-quality real-world studies, coordinated by independent research groups over the last 3 years, that reported major GIB events in patients given NOACs or vitamin K antagonists for patients with nonvalvular atrial fibrillation. The lowest risk of gastrointestinal bleeding was with apixaban compared with warfarin (hazard ratio (HR) for GIB for apixaban ranging between 0.45 (95% confidence interval (CI) 0.34 to 0.59) and 1.13 (95% CI 0.79 to 1.63)). Apixaban was associated with a lower risk of GI bleeding than dabigatran ((HR ranging between 0.39 (95% CI 0.27 to 0.58) and 0.95 (95% CI 0.65 to 1.18)) or rivaroxaban ((HR ranging between 0.33 (95% CI 0.22 to 0.49) and 0.82 (95% CI 0.62 to 1.08)). The results of our study confirm a low or a similar risk for major GIB between patients receiving apixaban or dabigatran compared with warfarin, and apixaban appears to be associated with the lowest risk of GIB.