Optimal Antithrombotic Regimens for Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention An Updated Network Meta-analysis

Importance: Antithrombotic treatment in patients with atrial fibrillation (AF) and percutaneous coronary intervention (PCI) presents a balancing act with regard to bleeding and ischemic risks. Objectives: To evaluate the safety and efficacy of 4 antithrombotic regimens by conducting an up-to-date network meta-analysis and to identify the optimal treatment for patients with AF undergoing PCI. Data Sources: Online computerized database (MEDLINE). Study Selection: Five randomized studies were included (N = 11542; WOEST, PIONEER AF-PCI, RE-DUAL PCI, AUGUSTUS, ENTRUST-AF PCI). Data Extraction and Synthesis: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used in this network meta-analysis, in which bayesian random-effects models were applied. The data were analyzed from September 9 to 29, 2019. Main Outcomes and Measures: The primary safety outcome was thrombolysis in myocardial infarction (TIMI) major bleeding and the primary efficacy outcome was trial-defined major adverse cardiovascular events (MACE). Results: The total number of participants included in the study was 11 532. The mean age of the participants ranged from 70 to 72 years, 69% to 83% were male, 20% to 26% were female, and the participants were predominantly white (>90%). Compared with vitamin K antagonists (VKA) plus dual antiplatelet therapy (DAPT) (reference), the odds ratios (ORs) (95% credible intervals) for TIMI major bleeding were 0.57 (0.31-1.00) for VKA plus P2Y12 inhibitor, 0.69 (0.40-1.16) for non-VKA oral anticoagulant (NOAC) plus DAPT, and 0.52 (0.35-0.79) for NOAC plus P2Y12 inhibitor. For MACE, using VKA plus DAPT as reference, the ORs (95% credible intervals) were 0.97 (0.64-1.42) for VKA plus P2Y12 inhibitor, 0.95 (0.64-1.39) for NOAC plus DAPT, and 1.03 (0.77-1.38) for NOAC plus P2Y12 inhibitor. Conclusions and Relevance: The findings of this study suggest that an antithrombotic regimen of VKA plus DAPT should generally be avoided, because regimens in which aspirin is discontinued may lead to lower bleeding risk and no difference in antithrombotic effectiveness. The use of a NOAC plus a P2Y12 inhibitor without aspirin may be the most favorable treatment option and the preferred antithrombotic regimen for most patients with AF undergoing PCI

Apixaban versus PhenpRocoumon: Oral AntiCoagulation plus antiplatelet tHerapy in patients with Acute Coronary Syndrome and Atrial Fibrillation (APPROACH-ACS-AF)

Background A regimen of dual (DAT) vs. triple (TAT) antithrombotic therapy reduces bleeding in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI). However, recent evidence suggests that DAT may be associated with an increased ischemic risk. This raises the question whether DAT rather than TAT should be recommended to AF patients that undergo PCI for acute coronary syndrome (ACS), carrying a particularly high risk of both bleeding and ischemic events, studied only as subgroups of previous trials. Methods and design The APPROACH-ACS-AF-(DZHK-7) trial is a multicenter prospective, randomized, open-label, blinded endpoint (PROBE) trial which will include patients presenting with an ACS managed by PCI and requiring oral anticoagulation (OAC) due to AF. The trial will test, whether a DAT-regimen comprising clopidogrel plus the non-Vitamin-K-antagonist oral anticoagulant (NOAC) apixaban is superior to a TAT-regimen of vitamin-K-antagonist (VKA) plus dual anti-platelet therapy (APT) with respect to bleeding. A total of 400 patients will be randomized 1:1 to a control-arm with guideline-recommended TAT with VKA plus clopidogrel and acetylsalicylic-acid and a study arm receiving DAT comprising apixaban plus clopidogrel. Patients will be followed-up for 6 months. The primary endpoint of the study is the cumulative incidence of BARC type ≥2 bleeding, secondary endpoints include a composite clinical ischemic outcome and net clinical outcome. Conclusions APPROACH-ACS-AF is the first trial dedicated to ACS patients, testing whether in terms of bleeding a DAT with NOAC is superior to a TAT regimen with VKA in high-risk ACS patients with AF

Impact of Dabigatran versus Phenprocoumon on ADP Induced Platelet Aggregation in Patients with Atrial Fibrillation with or without Concomitant Clopidogrel Therapy (the Dabi-ADP-1 and Dabi-ADP-2 Trials)

Background. A relevant number of patients receive triple therapy with clopidogrel, aspirin, and oral anticoagulation. Clopidogrel’s efficacy on ADP induced platelet function may be influenced by concomitant antithrombotic therapies. Data regarding the effect of dabigatran on platelet function is limited to in vitro studies and healthy individuals. Methods. The “Dabi-ADP-1” and “Dabi-ADP-2” trials randomized patients with atrial fibrillation to either dabigatran or phenprocoumon for a 2-week period. In Dabi-ADP-1 (n=70) patients with clopidogrel therapy were excluded and in Dabi-ADP-2 (n=46) patients had to be treated concomitantly with clopidogrel. The primary endpoint was ADP-induced platelet aggregation between dabigatran and phenprocoumon at 14 days. Secondary endpoints were ADPtest HS-, TRAP-, and COL-induced platelet aggregation. Results. There was no significant difference regarding the primary endpoint between both groups in either trial (Dabi-ADP-1: Dabigatran: 846 [650–983] AU × min versus phenprocoumon: 839 [666–1039] AU × min, P=0.90 and Dabi-ADP-2: 326 [268–462] versus 350 [214–535], P=0.70) or regarding the secondary endpoints, ADPtest HS-, TRAP-, and COL-induced platelet aggregation. Conclusion. Dabigatran as compared to phenprocoumon has no impact on ADP-induced platelet aggregation in atrial fibrillation patients neither with nor without concomitant clopidogrel therapy

Autocatalytic self-propagation of misfolded prion protein

Prions are thought to replicate in an autocatalytic process that converts cellular prion protein (PrP(C)) to the disease-associated misfolded PrP isoform (PrP(Sc)). Our study scrutinizes this hypothesis by in vitro protein misfolding cyclic amplification (PMCA). In serial transmission PMCA experiments, PrP(Sc) was inoculated into healthy hamster brain homogenate containing PrP(C). Misfolded PrP was amplified by rounds of sonication and incubation and reinoculated into fresh brain homogenate every 10 PMCA rounds. The amplification depended on PrP(C) substrate and could be inhibited by recombinant hamster PrP. In serial dilution experiments, newly formed misfolded and proteinase K-resistant PrP (PrPres) catalyzed the structural conversion of PrP(C) as efficiently as PrP(Sc) from brain of scrapie (263K)-infected hamsters, yielding an ≈300-fold total amplification of PrPres after 100 rounds, which confirms an autocatalytic PrP-misfolding cascade as postulated by the prion hypothesis. PrPres formation was not paralleled by replication of biological infectivity, which appears to require factors additional to PrP-misfolding autocatalysis

Safety and Efficacy of Antithrombotic Strategies in Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention:A Network Meta-analysis of Randomized Controlled Trials

Importance: The antithrombotic treatment of patients with atrial fibrillation (AF) and coronary artery disease, in particular with acute coronary syndrome (ACS) and/or percutaneous coronary intervention (PCI), poses a significant treatment dilemma in clinical practice. Objective: To study the safety and efficacy of different antithrombotic regimens using a network meta-analysis of randomized controlled trials in this population. Data Sources: PubMed, EMBASE, EBSCO, and Cochrane databases were searched to identify randomized controlled trials comparing antithrombotic regimens. Study Selection: Four randomized studies were included (n = 10026; WOEST, PIONEER AF-PCI, RE-DUAL PCI, and AUGUSTUS). Data Extraction and Synthesis: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used in this systematic review and network meta-analysis between 4 regimens using a Bayesian random-effects model. A pre hoc statistical analysis plan was written, and the review protocol was registered at PROSPERO. Data were analyzed between November 2018 and February 2019. Main Outcomes and Measures: The primary safety outcome was Thrombolysis in Myocardial Infarction (TIMI) major bleeding; secondary safety outcomes were combined TIMI major and minor bleeding, trial-defined primary bleeding events, intracranial hemorrhage, and hospitalization. The primary efficacy outcome was trial-defined major adverse cardiovascular events (MACE); secondary efficacy outcomes were individual components of MACE. Results: The overall prevalence of ACS varied from 28% to 61%. The mean age ranged from 70 to 72 years; 20% to 29% of the trial population were women; and most patients were at high risk for thromboembolic and bleeding events. Compared with a regimen of vitamin K antagonist (VKA) plus dual antiplatelet therapy (DAPT; P2Y12 inhibitor plus aspirin), the odds ratios (ORs) for TIMI major bleeding were 0.58 (95% CI, 0.31-1.08) for VKA plus P2Y12 inhibitor, 0.49 (95% CI, 0.30-0.82) for non-VKA oral anticoagulant (NOAC) plus P2Y12 inhibitor, and 0.70 (95% CI, 0.38-1.23) for NOAC plus DAPT. Compared with VKA plus DAPT, the ORs for MACE were 0.96 (95% CI, 0.60-1.46) for VKA plus P2Y12 inhibitor, 1.02 (95% CI, 0.71-1.47) for NOAC plus P2Y12 inhibitor, and 0.94 (95% CI, 0.60-1.45) for NOAC plus DAPT. Conclusions and Relevance: A regimen of NOACs plus P2Y12 inhibitor was associated with less bleeding compared with VKAs plus DAPT. Strategies omitting aspirin caused less bleeding, including intracranial bleeding, without significant difference in MACE, compared with strategies including aspirin. Our results support the use of NOAC plus P2Y12 inhibitor as the preferred regimen post-percutaneous coronary intervention for these high-risk patients with AF. A regimen of VKA plus DAPT should generally be avoided.