The quest for safer antithrombotic treatment regimens in patients with coronary artery disease: new strategies and paradigm shifts

The factors influencing the efficiency of drug-coated balloons

The drug-coated balloon (DCB) is an emerging percutaneous coronary intervention (PCI) device that delivers drugs to diseased vessels to decrease the rate of vascular stenosis. Recent clinical studies have demonstrated that DCBs tend to have both good safety and efficacy profiles, leading to extended application indications in the clinic, including in-stent restenosis (ISR) for metal stents such as drug-eluting stents (DESs), small vascular disease, bifurcation disease, large vascular disease, acute coronary syndrome (ACS), and high bleeding risk. However, some previous clinical data have suggested that DCBs performed less effectively than DESs. No studies or reviews have systematically discussed the improvement strategies for better DCB performance until now. Drug loss during the process of delivery to the target lesion and inefficient delivery of the coating drug to the diseased vascular wall are two key mechanisms that weaken the efficiency of DCBs. This review is the first to summarize the key influencing factors of DCB efficiency in terms of balloon structure and principles, and then it analyzes how these factors cause outcomes in practice based on current clinical trial studies of DCBs in the treatment of different types of lesions. We also provide some recommendations for improving DCBs to contribute to better DCB performance by improving the design of DCBs and combining other factors in clinical practice.

P2Y12 inhibitors monotherapy after short course of dual antiplatelet therapy in patients undergoing percutaneous coronary intervention: a meta-analysis of randomized clinical trials including 29 089 patients

AIMS

Dual antiplatelet therapy (DAPT) reduces the incidence of thrombotic complications at the cost of an increase in bleedings. New antiplatelet therapies focused on minimizing bleeding and maximizing antithrombotic effects are emerging. The aim of this study is to collect the current evidence coming from randomized controlled trials (RCTs) on early aspirin interruption after percutaneous coronary intervention (PCI) and current drug-eluting stent (DES) implantation and to perform a meta-analysis in order to evaluate the safety and efficacy of this strategy.

METHODS AND RESULTS

MEDLINE/PubMed was systematically screened for RCTs comparing P2Y12 inhibitors (P2Y12i) monotherapy after a maximum of 3 months of DAPT (S-DAPT) vs. DAPT for 12 months (DAPT) in patients undergoing PCI with DES. Baseline features were appraised. Major adverse cardiac and cerebrovascular events (MACCE: all causes of death, myocardial infarction, and stroke) and its single composites, stent thrombosis (ST) and Bleeding Academic Research Consortium (BARC) type 3 or 5 were considered and pooled with fixed and random-effects with inverse-variance weighting. A total of four RCTs including a total of 29 089 patients were identified. Overall, the majority of included patients suffered a stable coronary artery disease, while ST-elevation myocardial infarction was the least represented clinical presentation. Complex anatomical settings like left main intervention, bifurcations, and multi-lesions treatment were included although representing a minor part of the cases. At 1-year follow-up, MACCE rate was similar [odds ratio (OR) 0.90; 95% confidence intervals (CIs) 0.79-1.03] and any of its composites (all causes of death rate: OR 0.87; 95% CIs 0.71-1.06; myocardial infarction: OR 1.06; 95% CIs 0.90-1.26; stroke: OR 1.12; 95% CIs 0.82-1.53). Similarly, also ST rate was comparable in the two groups (OR 1.17; 95% CIs 0.83-1.64), while BARC 3 or 5 bleeding resulted significantly lower, adopting an S-DAPT strategy (OR 0.70; 95% CIs 0.58-0.86).

CONCLUSION

After a PCI with current DES, an S-DAPT strategy followed by a P2Y12i monotherapy was associated with a lower incidence of clinically relevant bleeding compared to 12 months DAPT, with no significant differences in terms of 1-year cardiovascular events.

Evolution of Clinical Thinking and Practice Regarding Aspirin: What Has Changed and Why?

Aspirin (ASA) is the original antiplatelet agent. Its routine use, long unquestioned for both primary and secondary prevention in cardiovascular disease, is under increasing scrutiny as the risk:benefit balance for ASA becomes less clear and other disease- and risk-modifying approaches are validated. It can be viewed as a significant advance in evidence-based medicine that the use of an inexpensive, readily available, long-validated therapy is being questioned in large, rigorous trials. In this overview we present the important questions surrounding a more informed approach to ASA therapy: duration of therapy, assessment of net clinical benefit, and timing of start and stop strategies. We also consider potential explanations for "breakthrough" thrombosis when patients are on ASA therapy. Other manuscripts in this Supplement address the specifics of primary prevention, secondary prevention, triple oral antithrombotic therapy, and the future of ASA in cardiovascular medicine.

Safety and efficacy of P2Y12 inhibitor monotherapy in patients undergoing percutaneous coronary interventions

Introduction: Antiplatelet therapy represents a key strategy for the prevention of thrombotic complications in patients with both acute and chronic coronary syndromes, particularly those undergoing percutaneous coronary intervention (PCI). Nevertheless, dual antiplatelet therapy (DAPT) is associated with a bleeding risk proportionate to its duration. Ever growing appreciation of the prognostic implications associated with bleeding and the development of safer stent platforms over the past years have led to a number of novel antiplatelet treatment strategies being tested among patients undergoing PCI. Areas covered: P2Y₁₂ inhibitor monotherapy after ashort course DAPT has emerged as ableeding reduction strategy to mitigate such risk while still preventing thrombotic complications. In this review we describe the latest evidence regarding the safety and efficacy of P2Y₁₂ inhibitor monotherapy in patients undergoing PCI in different clinical settings. Expert opinion: P2Y₁₂ inhibitor monotherapy after a brief period of DAPT has emerged as an effective approach to reduce the risk of bleeding without any tradeoff in efficacy (i.e., thrombotic complications). This strategy has shown consistent findings in a number of different clinical settings of patients undergoing PCI. Nevertheless, unanswered questions on the ideal patient and the precise P2Y₁₂ monotherapy regimen warrant further investigation.

Trial Design Principles for Patients at High Bleeding Risk Undergoing PCI: JACC Scientific Expert Panel

Investigating the balance of risk for thrombotic and bleeding events after percutaneous coronary intervention (PCI) is especially relevant for patients at high bleeding risk (HBR). The Academic Research Consortium for HBR recently proposed a consensus definition in an effort to standardize the patient population included in HBR trials. The aim of this consensus-based document, the second initiative from the Academic Research Consortium for HBR, is to propose recommendations to guide the design of clinical trials of devices and drugs in HBR patients undergoing PCI. The authors discuss the designs of trials in HBR patients undergoing PCI and various aspects of trial design specific to HBR patients, including target populations, intervention and control groups, primary and secondary outcomes, and timing of endpoint reporting.

Long-term monotherapy with ticagrelor after coronary stenting: the GLOBAL LEADERS study

Dual antiplatelet treatment is currently the mainstay of pharmacologic treatment for patients after coronary percutaneous interventions for stable or acute coronary syndrome. The treatment decreases the incidence of thrombotic complications, but is responsible for an increased risk of bleeding. The advances in interventional cardiology and the development of new coronary stents, allow for a significant reduction of haemorrhagic complications secondary to antithrombotic treatment by either decreasing their dose or limiting their duration. The GLOBAL LEADERS study failed to demonstrate, after 2 years of follow-up, an advantage for the monotherapy with ticagrelor as compared to standard dual antiplatelet regimen. Nevertheless, focused appraisal of the study results, provide for some positive and promising new considerations. In fact, even though the results of the GLOBAL LEADER trial have not changed the current clinical practice, they provide the starting point for the design of new trials aiming at comparing new antithrombotic regimens which could be not inferior in terms of efficacy, but superior in terms of safety.

[Combined Antithrombotic Therapy in Patients with a Stable Atherosclerotic Cardiovascular Diseases: What Direction did COMPASS Show?]

In patients with stable ischemic heart disease (IHD) and/or peripheral artery disease (PAD), current secondary prevention, including the antiplatelet monotherapy, is associated with a significant residual risk of recurrent cardiovascular complications (CVC). Practical application of results from many modern studies evaluating the effect of secondary prevention of atherothrombosis is complicated. An additional influence on coagulation may play a key role in prevention of atherothrombosis. In the COMPASS study, adding rivaroxaban 2.5 mg, b.i.d., to the acetylsalicylic acid (ASA) monotherapy significantly reduced the risk of death from cardiovascular complications, myocardial infarction or stroke, or all-cause death compared to the ASA monotherapy, in patients with IHD or PAD. The combination antithrombotic therapy was associated with an increased risk of major, but not fatal, or intracranial bleeding. In addition, PAD patients had a reduced risk of severe ischemic lower limb complications, including amputations. According to the subgroup analysis in the COMPASS study, supplementing ASA with rivaroxaban 2.5 mg, b.i.d., may appear most beneficial for patients with stable atherosclerotic disease and with a high risk of severe CVC without causing an increased risk of bleeding.

Short-term safety and long-term benefits of stent postdilation after primary percutaneous coronary intervention: Results of a cohort study

AIM

Achieving the optimal apposition of coronary stents during percutaneous coronary intervention is not always feasible. The risks and benefits of stent postdilation in primary percutaneous coronary intervention (PPCI) in patients with ST-elevation myocardial infarction (STEMI) have remained controversial. We sought to evaluate the immediate angiographic and long-term outcomes in patients with and without stent postdilation.

METHODS

A cohort of patients (n = 1,224) with STEMI, treated with PPCI (n = 500 postdilated; n = 724 controls), were studied. The flow grade, the myocardial blush grade, and the frame count were considered angiographic outcomes. The clinical outcomes were major adverse cardiovascular events (MACE)-comprising cardiac death, nonfatal MI, and repeat revascularization-and the device-oriented composite endpoint (DOCE)-consisting of cardiac death, target lesion revascularization, and target vessel revascularization.

RESULTS

The flow and myocardial blush grades were not different between the two groups, and the frame count was significantly lower in the postdilation group (15.7 ± 8.4 vs. 17 ± 10.4; p < .05). The patients were followed up for 348 ± 399 days. DOCE (2.2% vs. 5.8%) and cardiac mortality (1.2% vs. 3.2%) were lower in the postdilation group. In the fully adjusted propensity score-matched analysis, postdilation was associated with decreased DOCE (HR = 0.40 [0.18-0.87], p = .021).

CONCLUSIONS

Selective postdilation improved some angiographic and clinical outcomes and could not be discouraged in PPCI on patients with STEMI.

Role of oral anticoagulant therapy for secondary prevention in patients with stable atherothrombotic disease manifestations

Coronary artery disease and peripheral arterial disease are strong predictors of risk for a future ischemic event. Despite the utilization of effective secondary prevention strategies, the prevalence of ischemic recurrences remains high, underscoring the need for effective secondary prevention antithrombotic treatment regimens. To date, most of the tested approaches have been with the use of antiplatelet therapies, used either individually or in combination. However, most recent findings support the potential role of oral anticoagulant therapy in addition to antiplatelet therapy to reduce the risk of ischemic recurrences. This approach has been tested in both acute and stable settings of patients with cardiovascular disease manifestations. The present manuscript provides an overview on the rationale and clinical trial updates on the role of oral anticoagulant therapy, in particular rivaroxaban used at the so-called vascular protection dose, in adjunct to antiplatelet therapy (i.e. aspirin), a strategy known as dual pathway inhibition, for secondary prevention of ischemic recurrences in patients with stable atherosclerotic disease manifestations.

Evolving paradigms in antithrombotic therapy for anticoagulated patients undergoing coronary stenting

A sizable proportion of coronary artery disease (CAD) patients undergoing percutaneous coronary intervention (PCI) with stent implantation have an indication for treatment with oral anticoagulant therapy (OAC). The coexistence of atrial fibrillation (AF) and the need for PCI expose patients to a higher risk of developing thrombotic complications, and a multitargeted antithrombotic treatment strategy, addressing both platelet- and coagulation-mediated triggering mechanisms of thrombosis, is necessary for ensuring full protection from ischemic hazards. The increased bleeding risk identified with triple antithrombotic therapy has driven the search for alternative treatment modalities and pharmacological combination strategies aimed at achieving an optimal balance between safety and efficacy in this complex clinical scenario. Over a short time period, the paradigms surrounding the management of patients undergoing PCI who require OAC have substantially evolved. In this review, we summarize and critically evaluate the results of recent randomized clinical trials investigating the pharmacological management of patients who, in addition to antiplatelet therapy, have an indication for OAC treatment before or at the time of a PCI procedure.

Phospholipase Cγ2 Signaling Cascade Contribute to the Antiplatelet Effect of Notoginsenoside Fc

Scope: Bleeding, the main drawback of clinically used chemical anti-thrombotic drug is resulted from the unidirectional suppression of platelet activity. Therefore, dual-directional regulatory effect on platelet is the main preponderance of Panax notoginseng over these drugs. The dual-directional regulatory effect should be ascribed to the resourceful Panax notoginseng saponins (PNS). Clarifying the mechanism of main PNS in both inhibiting and promoting platelet aggregation will give a full outlook for the dual-directional regulatory effect. The present study is aimed at explaining the mechanism of Notoginsenoside Fc (Fc), a main PNS, in inhibiting platelet aggregation.

Methods: In the in vitro study, after incubating platelets with Fc and m-3M3FBS, platelet aggregation was triggered by thrombin, collagen or ADP. Platelet aggregation was measured by aggregometer. Phospholipase Cγ2 (PLCγ2) and protein kinase C (PKC) activities were studied by western blotting. Diacylglycerol (DAG), thromboxane B₂ (TXB₂) and 1,4,5-inositol trisphosphate (IP₃) concentrations were measured by corresponding ELISA kits. Calcium concentrations ([Ca²⁺]) were estimated through the fluorescence intensity emitted from Fluo-4. In the in vivo study, thrombus model was induced by FeCl₃. The effect of Fc on thrombosis was evaluated by measurement of protein content and observation of injured blood vessel.

Results: thrombin, collagen and ADP induced platelet aggregation were all suppressed by incubating platelets with Fc. Platelet PLCγ2 and subsequent DAG-PKC-TXA₂ and IP₃ were down-regulated by Fc as well. However, the basal [Ca²⁺] in platelet was not altered by Fc. Nevertheless, thrombin triggered activation of PLCγ2 and subsequent DAG-PKC-TXA₂ and IP₃-[Ca²⁺] were all abolished by Fc. Fc also attenuated platelet aggregation and PLCγ2 signaling activation induced by PLC activator, m-3M3FBS. In the in vivo study, FeCl₃ induced thrombosis in rat femoral artery was significantly alleviated by administration of Fc.

Conclusion: The results above suggested the antiplatelet and antithrombotic effects of Fc are carried out through oppression of PLCγ2 and subsequent DAG-PKC-TXA₂ and IP₃-[Ca²⁺]. The present study provided theoretical support for new anti-thrombotic drug exploitation by Panax notoginseng.

Diabetes and antiplatelet therapy: from bench to bedside

Diabetes mellitus (DM) is a metabolic disorder associated with accelerated atherogenesis and an increased risk of atherothrombotic complications. Multiple mechanisms contribute to the pro-thrombotic status which characterizes DM patients underscoring the importance of antiplatelet therapies used for secondary prevention in these patients. For many years, dual antiplatelet therapy (DAPT) with aspirin and the P2Y₁₂ inhibitor clopidogrel has represented the mainstay of treatment following an acute coronary syndrome (ACS) or in patients undergoing percutaneous coronary interventions (PCI). Although DAPT reduces the incidence of atherothrombotic recurrences, these rates remain high in DM patients underscoring the need for more efficacious therapies. Oral platelet P2Y₁₂ receptor inhibitors with enhanced potency, such as prasugrel and ticagrelor, as well as antiplatelet therapies such as vorapaxar inhibiting the thrombin-mediated platelet signaling pathway, constitute treatment opportunities for patients with DM and have shown to be associated with a greater reduction in ischemic recurrences, albeit at the cost of more bleeding. This article reviews currently available antiplatelet agents and delivers an update on the advances and drawbacks of these agents used for secondary prevention in DM patients experiencing an ACS or undergoing PCI.