Assessing Cancer Signal during Oral Antiplatelet Therapy in the Food and Drug Administration Adverse Event Reporting System: Mission Impossible

Whether aggressive prolonged dual antiplatelet therapy (DAPT) promotes solid cancer risks remains a critical unsolved issue. Since the evidence from randomized trials, affiliated U.S. Food and Drug Administration (FDA) reviews, meta-analyses, and national registries is mixed, the search is ongoing. The FDA Adverse Event Reporting System (FAERS) is a global passive surveillance repository requiring mandatory updates for serious events. We assessed the frequencies of co-reporting any cancers with oral antiplatelet agent (OAA) strategies in FAERS. We examined the entire FAERS database ( n  = 8,604,889) with regard to monotherapy or DAPT with OAA, suspected causative role, and co-reporting any cancers ( n  = 433,111). We extracted cancer cases during monotherapy with aspirin (20,984 out of 462,371 or 4.54%), clopidogrel (2,797 out of 62,791 or 4.45%), prasugrel (119 out of 4,364 or 2.73%), and ticagrelor (144 out of 8.268 or 1.71%). DAPT with clopidogrel reported (2,453 out of 58,101, or 4.22%); prasugrel (162 out of 4,036, or 4.01%); and ticagrelor (195 out of 5,302 or 3.68%) cancer reports all on top of aspirin. We conclude that FAERS is currently unreliable for adequate assessment of cancer risks during DAPT. The retrieved evidence appears random and sporadic, while associated cancers are heavily underreported or/and missed. Without stricter rules, better surveillance, and enforcements, oncology outcome research options in FAERS are challenging.

Management of antiplatelet therapy in patients with coronary stents undergoing noncardiac surgery: association with adverse events

BACKGROUND

Perioperative discontinuation of antiplatelet therapy (APT) in patients with coronary stents has been associated with major adverse cardiac events. Our aim was to analyse the perioperative management of APT in such patients and its relationship to the incidence of major adverse cardiac and cerebrovascular events (MACCE) and major bleeding events (MBE) in noncardiac surgery.

METHODS

We completed a prospective multicentre observational study of patients with coronary stents undergoing noncardiac surgery in 11 hospitals in Spain. The main objectives were to record perioperative events and prospectively analyse the management of APT, and to assess whether the different preoperative APT regimens were associated with MACCE and MBE.

RESULTS

Of 432 surgical procedures studied, 15% experienced a perioperative MACCE and 37% a MBE. Overall mortality was 3.0%. Presurgical APT was prescribed in 95% of procedures, and was preoperatively discontinued in 15%. Surgery was urgent or emergent in 22% of patients, 31% were ASA IV, and 38% had a Revised Cardiac Risk Index of IV. MACCE were related to recent myocardial infarction (P=0.038), chronic kidney disease (P<0.001), insulin-dependent diabetes (P=0.006) and no preoperative APT (P=0.018). MBE also increased MACCE risk (P<0.001). We found statin therapy (P=0.049) and obesity (P=0.016) to be protective factors for MACCE.

CONCLUSIONS

Patients with coronary stents undergoing noncardiac surgery suffer a high incidence of perioperative adverse events, even with perioperative APT. Major adverse cardiac and cerebrovascular events are mainly related to previous medical conditions and perioperative major bleeingn events. Our findings should be treated with caution when applied to an elective surgery population.

CLINICAL TRIAL REGISTRATION

NCT01171612.

Platelet Integrins in Tumor Metastasis: Do They Represent a Therapeutic Target?

Platelets are small anucleated cell fragments that ensure the arrest of bleeding after a vessel wall injury. They are also involved in non-hemostatic function such as development, immunity, inflammation, and in the hematogeneous phase of metastasis. While the role of platelets in tumor metastasis has been recognized for 60 years, the molecular mechanism underlying this process remains largely unclear. Platelets physically and functionally interact with various tumor cells through surface receptors including integrins. Platelets express five integrins at their surface, namely α2β1, α5β1, α6β1, αvβ3, and αIIbβ3, which bind preferentially to collagen, fibronectin, laminin, vitronectin, and fibrinogen, respectively. The main role of platelet integrins is to ensure platelet adhesion and aggregation at sites of vascular injury. Two of these, α6β1 and αIIbβ3, were proposed to participate in platelet–tumor cell interaction and in tumor metastasis. It has also been reported that pharmacological agents targeting both integrins efficiently reduce experimental metastasis, suggesting that platelet integrins may represent new anti-metastatic targets. This review focuses on the role of platelet integrins in tumor metastasis and discusses whether these receptors may represent new potential targets for novel anti-metastatic approaches.

Aspirin in the Food and Drug Administration Adverse Event Reporting System: Missing Demographics and Underreporting

Background  The U.S. Food and Drug Administration (FDA) Adverse Event (AE) Reporting System (FAERS) is a global passive surveillance repository requiring mandatory updates by pharmaceutical manufacturers. Oral antiplatelet agents (OAAs) including aspirin (acetylsalicylic acid [ASA]) are broadly used to prevent thrombosis, at the expense of extra bleeding risks. However, the OAA filing quality and their comparative patterns in FAERS are unknown. We assessed completeness of original annual FAERS reports for OAA with special attention on ASA.

Methods  We extracted AE cases co-reported with OAA including ASA, clopidogrel, prasugrel, ticagrelor, vorapaxar, or their combination. The 2015 FAERS cases were examined based on OAA distribution, suspected causative role, missing gender or age, and most common AEs after ASA.

Results  A total of 1,187,729 reports qualified the inclusion criteria. The majority ( n  = 1,121,989) of the reports contain no reference of OAA, while 65,730 reports contain reference of at least one OAA, including 47,900 ASA cases. Therapy with ASA was heavily (>50%) underreported when used with prasugrel or ticagrelor, but still dominant (72.8%) among OAAs, followed by clopidogrel (18.7%), prasugrel (4.1%), ticagrelor (3.6%), and anecdotal vorapaxar (0.05%). Despite current recommendations, some (0.73%) reports contain multi-OAAs. The primary role of ASA in AE reporting was seldom (<1%), followed by clopidogrel (2.9%), prasugrel (3.7%), and highest for ticagrelor (9.3%). Missing gender after OAA was not common (<10%), but age was missing in approximately 25% of reports. Bleeding was the most frequent AE associated with ASA.

Conclusion  The quality of reporting for OAA in general and ASA in particular can be improved by stricter FDA rules, better surveillance, and enforcements. Heavy ASA underreporting during dual antiplatelet therapy and missed demographic variables challenge outcome research capacities for establishing drug interactions in FAERS.

Temporal Trends in the Use of Antiplatelet Therapy in Patients With Acute Coronary Syndromes

BACKGROUND

Current clinical guidelines of acute coronary syndromes (ACS) recommend the use of potent antiplatelet therapy, prasugrel or ticagrelor, because both drugs consistently reduce cardiovascular events.

PURPOSE

The aim of this study was to examine temporal changes in the use of optimal antiplatelet therapy in patients with ACS.

METHODS

A total of 1717 consecutive patients admitted for ACS in 3 tertiary hospitals from February 2014 to December 2015 were enrolled. We divided these 23 months into 4 semesters: period I (0-5 months), period II (6-11 months), period III (12-17 months), and period IV (17-23 months). Demographic, clinical, and treatment data were collected both at admission and at discharge.

RESULTS

Treatment with clopidogrel remained constant throughout the periods (52%, 50%, 44%, and 50% for periods I, II, III, and IV, respectively), whereas a progressive increase in ticagrelor treatment was observed (15%, 25%, 26%, and 28%; P = .001). Indeed, new P2Y12 agents showed an increase from 47% at the first semester to 65% in patients with ST-segment elevation myocardial infarction (STEMI), and in patients younger than 75 years from 36% to 53%. However, for patients older than 75 years, diabetic, and patients with end-stage kidney disease, clopidogrel was the second most commonly used antiplatelet agent.

CONCLUSION

In this real-life registry of patients with ACS, we observed there is still a high rate of use of clopidogrel, despite guidelines recommendations, and our analyses also showed a trend toward the use of ticagrelor. Patients who received new antiplatelet agents were patients with STEMI, younger than 75 years, and with less comorbidities. However, the use of ticagrelor and prasugrel remains low, highlighting a therapeutic inertia with considerable gap between evidence-based clinical guidelines and daily clinical practice.

The progress in the research of antiplatelet agents (1995-2017)

Antiplatelet therapy displays a critical role in the treatment and prevention of antithrombotic disorders. Many new antiplatelet agents have been developed following the emergence of various clinical limitations of classical antiplatelet drugs. This review covers mainly the recent advances in the development of P2Y₁₂ antagonists and GPIIb/IIIa antagonists. Meanwhile, it summarizes promising approaches to new platelet surface receptors such as prostanoid EP3 receptor, thromboxane A₂ prostanoid receptor, protease-activated receptors, GPIb-IX-V receptor and P-selectin. In addition, PI3K_β, a critical protein at the inside signaling pathway of platelet activation is also mentioned as an important antiplatelet target. Moreover, the development of respective drug candidates is discussed in detail.

Antithrombotic therapy in end-stage renal disease

The delicate balance of risk vs. benefit of using antiplatelet and antithrombotic agents in the general population is well established. The decision to use these agents in the end stage renal disease (ESRD) population remains complex and difficult. The concomitant association of a prothombotic state with high risk of bleeding in the ESRD population requires individualization and careful clinical judgment before implementing such therapy. There remains a paucity of clinical trials and lack of substantial evidence in literature for safe and effective use of antithrombotic drugs in patients with advanced chronic kidney disease. The current review summarizes the pros and cons of using antiplatelet and antithrombotic agents in primary and secondary prevention of cardiovascular events, evaluate the risks with routine use of anticoagulation for cerebrovascular stroke prevention with nonvalvular atrial fibrillation and role of newer oral anticoagulants as alternate agents in the dialysis population.

Comparative efficacy and safety of antiplatelet agents in cerebral ischemic disease: A network meta-analysis

We performed a network meta-analysis (NMA) to enhance the corresponding evidence of the relative efficacy and safety of different antiplatelet agents in cerebral ischemic disease. PubMed and EMBASE were searched systematically for relevant studies. Outcomes were compared using odds ratios and 95% credible intervals. Each agent was ranked according to the value of surface under the cumulative ranking curve (SUCRA). Publication bias was evaluated by funnel plots, while consistency between direct and indirect comparison was analyzed by node-splitting and heat plots. Besides, the clustering technique was used to categorize similar agents. A number of 44 eligible studies with 148 578 patients were included in this NMA. In terms of efficacy (including mortality, recurrent stroke, and vascular event), all six interventions were better than placebo. clopidogrel (Clop) and aspirin (ASA)+Clop were the best two interventions from SUCRA. However, the performance of ASA+Clop declined significantly when considering safety (including myocardial infarction, all-cause withdrawal, and intracranial hemorrhage), especially worse in intracranial hemorrhage. In conclusion, Clop was potentially the most preferable treatment for preventing cerebral ischemic in terms of efficacy and safety. However, the addition of ASA was associated with a potential increase in intracranial hemorrhage, therefore, combination therapy of ASA and Clop should be introduced with caution although it may be more effective than the monotherapy of ASA.

Maresin 1 induces a novel pro-resolving phenotype in human platelets

Essentials Specialized proresolving mediators (SPMs) promote the resolution of inflammation. This study sought to investigate the effects of SPMs on human platelet function. The SPM, Maresin 1, enhanced hemostatic, but suppressed inflammatory functions of platelets. SPMs uniquely regulate platelet function and may represent a new class of antiplatelet agents.

SUMMARY

Background Antiplatelet therapy is a cornerstone of modern medical practice and is routinely employed to reduce the likelihood of myocardial infarction, thrombosis and stroke. However, current antiplatelet therapies, such as aspirin, often have adverse side-effects, including increased risk of bleeding, and some patients are relatively 'aspirin-resistant'. Platelets are intimately involved in hemostasis and inflammation, and clinical consequences are associated with excessive or insufficient platelet activation. Objectives A major unmet need in the field of hematology is the development of new agents that safely prevent unwanted platelet activation in patients with underlying cardiovascular disease, while minimizing the risk of bleeding. Here, we investigate the potential of endogenously produced, specialized pro-resolving mediators (SPMs) as novel antiplatelet agents. SPMs are a recently discovered class of lipid-derived molecules that drive the resolution of inflammation without being overtly immunosuppressive. Methods Human platelets were treated with lipoxin A4, resolvin D1, resolvin D2, 17-HDHA or maresin 1 for 15 min, then were subjected to platelet function tests, including spreading, aggregation and inflammatory mediator release. Results We show for the first time that human platelets express the SPM receptors, GPR32 and ALX. Furthermore, our data demonstrate that maresin 1 differentially regulates platelet hemostatic function by enhancing platelet aggregation and spreading, while suppressing release of proinflammatory and prothrombotic mediators. Conclusions These data support the concept that SPMs differentially regulate platelet function and may represent a novel class of antiplatelet agents. SPMs also may play an important role in the resolution of inflammation in cardiovascular diseases.

2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. These guidelines, based on systematic methods to evaluate and classify evidence, provide a cornerstone of quality cardiovascular care.

In response to reports from the Institute of Medicine1 ,2 and a mandate to evaluate new knowledge and maintain relevance at the point of care, the ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) modified its methodology.3 –5 The relationships among guidelines, data standards, appropriate use criteria, and performance measures are addressed elsewhere.5

2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. These guidelines, based on systematic methods to evaluate and classify evidence, provide a cornerstone of quality cardiovascular care.

In response to reports from the Institute of Medicine1 ,2 and a mandate to evaluate new knowledge and maintain relevance at the point of care, the ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) modified its methodology.3 –5 The relationships among guidelines, data standards, appropriate use criteria, and performance measures are addressed elsewhere.5

Reintroduction of anti-thrombotic therapy after a gastrointestinal haemorrhage: if and when?

Gastrointestinal haemorrhage is a common clinical scenario and, in those using antithrombotic agents, the risk is significantly increased. Management of these patients, in terms of initial resuscitation is well established and numerous guidelines exist in this area. However, few studies have addressed the subsequent dilemma of if and when antithrombotic agents should be reintroduced. Consequently, practice is variable and not necessarily evidenced-based. Overall, for patients that are either anticoagulated or using antiplatelet drugs for secondary prophylaxis, there is a clear benefit to restarting these agents. However, there is limited data to guide when this should occur. For individuals at low risk of re-bleeding, current guidelines suggest single agent aspirin can be continued without interruption, assuming haemostatic control has been confirmed endoscopically. For those at higher bleeding risk, aspirin should be withheld, but reintroduced early (within 3 days of index endoscopy). However, randomised evidence is lacking, as are studies including more modern agents or combined anticoagulant/ antiplatelet regimens. As such, guidance statements are limited and management suggestions must be extrapolated from clinical trials, retrospective studies and data relating specifically to warfarin and aspirin. The intention of this review is to summarise what evidence is available and, where this is lacking, suggest pragmatic management options based on a risk-benefit assessment of thromboembolism and recurrent bleeding.

Aspiration thrombectomy and intracoronary tirofiban via GuideLiner® catheter for a thrombosed aneurysmal vessel

A 52-year-old Asian male with no traditional risk factors for coronary artery disease presented with acute coronary syndrome. Coronary angiography showed complete thrombotic occlusion of the left circumflex with a large thrombus burden in the setting of diffuse aneurysmal enlargement of the coronary arteries consistent with antecedent Kawasaki disease. Manual thrombectomy with adjunctive intracoronary tirofiban was performed utilizing the GuideLiner catheter^® (Vascular Solutions, Inc., MN, USA). Stent implantation was deferred. Follow-up imaging 48 h later showed preserved coronary flow and decreased thrombus burden. The GuideLiner catheter, a monorail guiding device, served a novel role in thrombus aspiration and intracoronary medication delivery.

Bleeding risk of endoscopic ultrasound-guided fine-needle aspiration in patients undergoing antithrombotic therapy

OBJECTIVES

Bleeding events related to endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) are rare. However, for patients treated with antithrombotic agents, the bleeding risk of EUS-FNA is uncertain. Hence, the aim of this study was to assess the bleeding event rate associated with EUS-FNA in patients receiving antithrombotic treatment.

METHODS

A retrospective study was conducted in 742 consecutive patients who underwent EUS-FNA for solid lesions between 2008 and 2015. We compared the bleeding event rates among patients who were not administered antithrombotic agents, those whose agent use was discontinued, those who continued treatment with aspirin or cilostazol, and those who were administered heparin as a replacement.

RESULTS

There were 131 patients (17.7 %) treated with antithrombotic agents. Seven experienced bleeding events, and the overall bleeding event rate was 0.9 % (7/742). All bleeding events were intraoperative; there were no postoperative bleeding episodes. Subgroup analysis by antithrombotic agent revealed bleeding event rates of 1.0 % (6/611), 0 % (0/62), 1.6 % (1/61), and 0 % (0/8) for the non-administration, discontinuation of agents, continuation of aspirin or cilostazol, and heparin replacement groups, respectively. Only one severe bleeding event necessitated hemostatic treatment (1/742; 0.1 %); this occurred in a patient in the non-administration group, and there were no severe bleeding events in patients receiving antithrombotic treatment.

CONCLUSIONS

The present study found a low incidence of EUS-FNA-related bleeding in patients receiving antithrombotic treatment. The bleeding event rate was low even in patients who underwent EUS-FNA while continuing aspirin or cilostazol.

Antithrombotic prophylaxis of atrial fibrillation in an Italian real-world setting: a retrospective study

OBJECTIVES

The aims of this study were to assess the prevalence of diagnosed atrial fibrillation (AF), the drug use in patients with AF in terms of antithrombotic (AT) strategies used and the compliance with treatment, and to describe the characteristics of patients affected by AF in relation to treatment.

METHODS

The data collected were provided from databases of general practitioners (GPs) of the Local Health Unit of Bologna in Italy. From January 1, 2009, to December 31, 2012, all subjects aged ≥18 years followed by the 44 GPs enrolled in the study were evaluated, and the subjects with a diagnosis of AF were included in the analysis.

RESULTS

From 2009 to 2012, we identified 1,413 patients with a diagnosis of AF (2.09% of 67,517 patients of the 44 GPs). A total of 1,413 patients with a diagnosis of AF (2.09% of 67,517 patients of the 44 GPs) were enrolled in the study. During the study, 14% of the enrolled patients did not receive any prescription of ATs, 30% and 39.56% were treated only with antiplatelet (AP) agents and oral anticoagulants (OACs), respectively, and 16.28% of the patients received prescriptions for both an OAC and an AP agent; of the patients receiving prescriptions for both, only 4.17% received these therapies at the same time. Among the OAC users, the percentage of patients still on treatment with the index drug during the last 3 months of observation was 76.9%.

CONCLUSION

Our findings emphasize that in an Italian real-world setting, the burden of AF in general population from a public health point of view underscores the need for improvement in utilization of appropriate ATs in patients with known AF.

Effects of autologous platelet transfusion on platelet inhibition in ticagrelor-treated and clopidogrel-treated subjects

Essentials Limited data on hemostatic benefits of platelet transfusion (PT) exist. 44 healthy subjects had a single dose of ticagrelor or clopidogrel ± autologous PT post-dosing. PT did not reverse ticagrelor's antiplatelet effects and had minimal impact post clopidogrel. Post-ticagrelor, PT is unlikely to be beneficial, and the benefits post-clopidogrel are unknown.

SUMMARY

Background Antiplatelet agents increase bleeding risk. Few data on hemostatic benefits of platelet transfusion exist. Objective To assess the effect of autologous platelet transfusion on ticagrelor-mediated and clopidogrel-mediated platelet inhibition in a single-center, open-label, randomized, cross-over study (NCT01744288). Methods Forty-four healthy subjects received ticagrelor (180 mg) or clopidogrel (600 mg; two functional CYP2C19 alleles [*1 or *17] required) with or without platelet transfusion (14-day washout). Subjects received one autologous platelet apheresis unit (approximately six pooled donor platelet units) 24 h (n = 15) or 48 h (n = 13) after ticagrelor or 48 h after clopidogrel (n = 16). Platelet apheresis was conducted 72 h before transfusion. Aspirin (81 mg per day) was taken from after apheresis until 24 h before transfusion. P2Y12 reaction units (PRUs) and inhibition of platelet aggregation (IPA) induced by ADP were measured. Results Mean age and body mass index were 30 years (standard deviation [SD] 6 years) and 26.9 kg m-2 (SD 4.0 kg m-2 ), respectively; 98% of subjects were men, and 39 of 44 completed treatment. Platelet transfusion 24 h after ticagrelor had minimal effects on IPA or PRU values within 48 h after transfusion. Platelet transfusion 48 h after ticagrelor also had minimal effects on IPA or PRU values at most post-transfusion times. Platelet transfusion 48 h after clopidogrel, versus no transfusion, had a small reversing effect on IPA (24 h, 36 h, and 48 h) and PRU values (12 h, 24 h, and 36 h) after transfusion. Conclusions Autologous platelet transfusion is unlikely to be of clinical benefit in reversing the antiplatelet effects of ticagrelor. The clinical relevance of the small effects seen with clopidogrel is unknown.

Human recombinant alkaline phosphatase inhibits ex vivo platelet activation in humans

Sepsis-associated acute kidney injury (AKI) is associated with high morbidity and mortality. Excessive platelet activation contributes to AKI through the formation of microthrombi and amplification of systemic inflammation. Two phase II trials demonstrated that bovine-intestinal alkaline phosphatase (AP) improved renal function in critically ill patients with sepsis-associated AKI. In this study, we characterised the platelet-inhibiting effects of a human recombinant AP. Whole blood and platelet-rich plasma (PRP) of healthy volunteers (n=6) was pre-treated ex vivo with recAP, whereafter platelet reactivity to ADP, collagen-related peptide (CRP-XL) and Pam3CSK4 was determined by flow cytometry. RecAP (40 U/ml) reduced the platelet reactivity to ADP (inhibition with a median of 47 %, interquartile range 43-49 %; p<0.001) and tended to reduce platelet reactivity to CRP-XL (9 %, 2-25 %; p=0.08) in whole blood. The platelet-inhibiting effects of recAP were more pronounced in PRP both for ADP- (64 %, 54-68 %; p=0.002) and CRP-XL-stimulated samples (60 %, 46-71 %; p=0.002). RecAP rapidly converted ADP into adenosine, whereas antagonism of the A2A adenosine receptor partially reversed the platelet inhibitory effects of recAP. Platelets of septic shock patients (n=5) showed a 31% (22-34%; p=0.03) more pronounced reactivity compared to healthy volunteers, and this was completely reversed by recAP treatment. In conclusion, we demonstrate that recAP inhibits ex vivo human platelet activation through dephosphorylation of ADP and formation of adenosine as its turnover product. RecAP is able to reverse the platelet hyperreactivity present in septic shock patients. These effects may contribute to the beneficial effects of recAP as a new therapeutic candidate for sepsis-associated AKI.

Anticoagulant and Antiplatelet Prescribing Patterns for Patients with Atrial Fibrillation after Percutaneous Coronary Intervention

BACKGROUND

Current guidelines recommend triple antithrombotic therapy (TAT), defined as acetylsalicylic acid (ASA), clopidogrel, and warfarin, for patients with nonvalvular atrial fibrillation who have undergone percutaneous coronary intervention with stent implantation. The choice of anticoagulant/antiplatelet therapy in this population is ambiguous and complex, and prescribing patterns are not well documented.

OBJECTIVE

To characterize local prescribing patterns for anticoagulant/antiplatelet therapy after percutaneous coronary intervention in patients with nonvalvular atrial fibrillation.

METHODS

A chart review was conducted at a single quaternary cardiology centre. Patients with nonvalvular atrial fibrillation were identified via medical records, and those who underwent percutaneous coronary intervention were identified using a local clinical patient registry. Adult inpatients with nonvalvular atrial fibrillation and a CHADS2 score (based on congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, prior stroke) of 1 or higher who underwent percutaneous coronary intervention from 2011 to 2013 were included. Patients undergoing cardiovascular surgery or transcatheter aortic valve replacement, those with mechanical devices requiring anticoagulation, and those with an allergy to any component of TAT were excluded.

RESULTS

Seventy patients were included. The median age was 75 years, and 52 (74%) were men. At discharge, 30 (43%) were receiving TAT and 27 (39%) were receiving dual antiplatelet therapy (clopidogrel and ASA). No patients received the combination of warfarin and clopidogrel. Among those who received TAT, 90% (19 of 21) who received a bare metal stent had a recommended duration of 1 month, and 75% (6 of 8) who received a drug-eluting stent had a recommended duration of 1 year. Direct-acting oral anticoagulants with 2 antiplatelet drugs were prescribed for 9% (6 of 70) of the patients, and 10% (7 of 70) received ticagrelor and ASA with or without warfarin. Overall, the combination of ASA, oral anticoagulant, and P2Y12 inhibitor was used for 54% (38/70) of the patients.

CONCLUSIONS

Fewer than half of the patients in this study received TAT, and almost 20% received non-evidence-based therapy with a direct-acting oral anticoagulant or ticagrelor, alone or in combination. Despite current guideline recommendations, the rate of TAT utilization was lower than rates reported in the literature.

A rabbit model of cerebral microembolic signals for translational research: preclinical validation for aspirin and clopidogrel

Essentials Microembolic signal (MES) is an independent predictor of stroke risk in patients. A rabbit model of cerebral microembolic signals was established. Therapeutic efficacy was demonstrated for aspirin and clopidogrel on microembolic signals. Potential translational value of this preclinical model of MES was demonstrated.

SUMMARY

Objectives Cerebral microembolic signals (MESs) detected by transcranial Doppler (TCD) ultrasound constitute an independent predictor of stroke risk and prognosis. The aim of this study was to develop a novel preclinical model of MESs to facilitate translational research. Methods A clinical TCD ultrasound machine was used to detect MESs in the cerebral circulation of New Zealand White rabbits. Technical feasibility was assessed for the measurement of MESs in the middle cerebral artery (MCA) by TCD. FeCl3 -induced carotid arterial thrombosis was optimized for the generation of endogenous microemboli. Ascending doses of two antithrombotic agents (aspirin and clopidogrel) were evaluated individually and in combination for their effects on both arterial thrombosis and MESs in a 30% FeCl3 -induced carotid arterial thrombosis model, along with ex vivo functional assays. Results Dose-dependent FeCl3 -induced arterial thrombosis studies showed that 30% FeCl3 resulted in the most consistent and reproducible MESs in the MCA (3.3 ± 0.7 MESs h(-1) ). Ascending-dose studies showed that the effective doses for 50% inhibition (ED50 ) of thrombus formation, based on integrated blood flow and thrombus weight, respectively, were 3.1 mg kg(-1) and 4.2 mg kg(-1) orally for aspirin, and 0.3 mg kg(-1) and 0.28 mg kg(-1) orally for clopidogrel. The ED50 values for MES incidence were 12.7 mg kg(-1) orally for aspirin, and 0.25 mg kg(-1) orally for clopidogrel. Dual treatment with aspirin (5 mg kg(-1) ) and clopidogel (0.3 mg kg(-1) ) resulted in significant reductions in cerebral MESs (P < 0.05) as compared with monotherapy with either agent. Conclusions Our study demonstrated the successful establishment of the MES model in rabbits, and it may provide translational value for MESs and ischemic stroke research.

Impact of Optimal Medical Therapy in the Dual Antiplatelet Therapy Study

BACKGROUND

Continued dual antiplatelet therapy and optimal medical therapy (OMT) improve outcomes in selected patient populations with established coronary heart disease, but whether OMT modifies the treatment effect of dual antiplatelet therapy is unknown.

METHODS

The DAPT (Dual Antiplatelet Therapy) Study, a double-blind trial, randomly assigned 11 648 patients who had undergone coronary stenting and completed 1 year of dual antiplatelet therapy without major bleeding or ischemic events to an additional 18 months of continued thienopyridine or placebo. OMT was defined as a combination of statin, β-blocker, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use in patients with an American College of Cardiology/American Heart Association class I indication for each medication. Per protocol, all patients were treated with 75 to 325 mg aspirin daily. End points included myocardial infarction, major adverse cardiovascular and cerebrovascular events, and Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Arteries moderate or severe bleeding events.

RESULTS

Of 11 643 randomly assigned patients with complete medication data, 63% were on OMT. Between 12 and 30 months, continued thienopyridine reduced myocardial infarction in comparison with placebo in both groups (on OMT 2.1% versus 3.3%, hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.48-0.86; P=0.003; off OMT 2.2% versus 5.2%, HR, 0.41; CI, 0.29-0.58; P<0.001; interaction P=0.103). Comparing continued thienopyridine versus placebo, rates of major adverse cardiovascular and cerebrovascular events were 4.2% versus 5.0% among patients on OMT (HR, 0.82; CI, 0.66-1.02; P=0.077) and 4.5% versus 7.0% among those off OMT (HR, 0.63; CI, 0.49-0.82; P<0.001; interaction P=0.250); rates of bleeding for thienopyridine versus placebo in patients on OMT were 2.2% versus 1.0% (HR, 2.13; CI, 1.43-3.17; P<0.001), and in patients off OMT were 2.8% versus 2.2% (HR, 1.30; CI, 0.88-1.92; P=0.189; interaction P=0.073). Overall, patients on OMT had lower rates of myocardial infarction (2.7% versus 3.7%, P=0.003), major adverse cardiovascular and cerebrovascular events (4.6% versus 5.7%, P=0.007), and bleeding (1.6% versus 2.5%, P<0.001) in comparison with patients off OMT. Rates of stent thrombosis (0.8% versus 1.0%, P=0.171) and death (1.6% versus 1.9%, P=0.155) did not differ.

CONCLUSIONS

Continued thienopyridine therapy reduced the rate of myocardial infarction regardless of OMT status and had consistent effects on reduction in major adverse cardiovascular and cerebrovascular events and increased bleeding.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov. Unique identifier: NCT00977938.

Prior Antithrombotic Use Is Associated With Favorable Mortality and Functional Outcomes in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Antithrombotics are the mainstay of treatment in primary and secondary prevention of stroke, and their use before an acute event may be associated with better outcomes.

METHODS

Using data from Get With The Guidelines-Stroke with over half a million acute ischemic strokes recorded between October 2011 and March 2014 (n=540 993) from 1661 hospitals across the United States, we examined the unadjusted and adjusted associations between previous antithrombotic use and clinical outcomes.

RESULTS

There were 250 104 (46%) stroke patients not receiving any antithrombotic before stroke; of whom approximately one third had a documented previous vascular indication. After controlling for clinical and hospital factors, patients who were receiving antithrombotics before stroke had better outcomes than those who did not, regardless of whether a previous vascular indication was present or not: adjusted odds ratio (95% confidence intervals) were 0.82 (0.80-0.84) for in-hospital mortality, 1.18 (1.16-1.19) for home as the discharge destination, 1.15 (1.13-1.16) for independent ambulatory status at discharge, and 1.15 (1.12-1.17) for discharge modified Rankin Scale score of 0 or 1.

CONCLUSIONS

Previous antithrombotic therapy was independently associated with improved clinical outcomes after acute ischemic stroke. Ensuring the use of antithrombotics in appropriate patient populations may be associated with benefits beyond stroke prevention.

Risk factors for the effect of anticoagulant and antiplatelet agents on perioperative blood loss following proximal femoral fractures

To examine the effect of oral anticoagulant and antiplatelet agents on perioperative blood loss following proximal femoral fractures and to identify the risk factors associated with perioperative blood loss.Retrospective cross-sectional study.In a retrospective cross-sectional study, we treated 334 consecutive patients with proximal femoral fractures (100 who received anticoagulant or antiplatelet drugs and 234 who did not) and an overall mean age of 85.5 years (standard deviation 8.2 years). We performed retrospective multivariate analysis to determine the independent factors related to perioperative decreases in the hemoglobin (Hb) level, a proxy for blood loss.Multivariate analysis confirmed that anticoagulant or antiplatelet drugs significantly affected decreases in the Hb level (regression coefficient [RC], 0.61; 95% confidence interval [CI], 0.14-1.08; P = 0.01). In addition to anticoagulant or antiplatelet drugs, multivariate analysis confirmed that the fracture type (Orthopedic Trauma Association classification A2: RC, 1.19; 95% CI, 0.71-1.67; P < 0.01; A3: RC, 2.47; 95% CI, 1.41-3.53; P < 0.01), platelet count (RC, -0.08; 95% CI, -0.12 to -0.04; P < 0.01), and operative time (RC, 0.02; 95% CI, 0.004-0.03; P = 0.01) affected the decreases in Hb level.The use of anticoagulants and antiplatelet agents is an independent risk factor for perioperative blood loss following proximal femoral fractures. Fracture type, platelet count, and operative time also affect perioperative blood loss. The fracture type was the greatest contributing factor to perioperative blood loss.Level of evidence grade: Prognostic level III.

Allosterism-based simultaneous, dual anticoagulant and antiplatelet action: allosteric inhibitor targeting the glycoprotein Ibα-binding and heparin-binding site of thrombin

BACKGROUND

Allosteric inhibition is a promising approach for developing a new group of anticoagulants with potentially reduced bleeding consequences. Recently, we designed sulfated β-O4 lignin (SbO4L) as an allosteric inhibitor that targets exosite 2 of thrombin to reduce fibrinogen cleavage through allostery and compete with glycoprotein Ibα to reduce platelet activation.

OBJECTIVE

To assess: (i) the antithrombotic potential of a novel approach of simultaneous exosite 2-dependent allosteric inhibition of thrombin and competitive inhibition of platelet activation; and (ii) the promise of SbO4L as the first-in-class antithrombotic agent.

METHODS

A combination of whole blood thromboelastography, hemostasis analysis, mouse arterial thrombosis models and mouse tail bleeding studies were used to assess antithrombotic potential.

RESULTS AND CONCLUSIONS

SbO4L extended the clot initiation time, and reduced maximal clot strength, platelet contractile force, and the clot elastic modulus, suggesting dual anticoagulant and antiplatelet effects. These effects were comparable to those observed with enoxaparin. A dose of 1 mg of SbO4L per mouse prevented occlusion in 100% of arteries, and lower doses resulted in a proportionally reduced response. Likewise, the time to occlusion increased by ~ 70% with a 0.5-mg dose in the mouse Rose Bengal thrombosis model. Finally, tail bleeding studies demonstrated that SbO4L does not increase bleeding propensity. In comparison, a 0.3-mg dose of enoxaparin increased the bleeding time and blood volume loss. Overall, this study highlights the promise of the allosteric inhibition approach, and presents SbO4L as a novel anticoagulant with potentially reduced bleeding side effects.