Antiphospholipid antibodies in patients with dysglycaemia: A neglected cardiovascular risk factor?

BACKGROUND

Cardiovascular disease is a serious complication in patients with dysglycaemia, defined as either type 2 diabetes or impaired glucose tolerance. Research focusing on the identification of potential markers for atherothrombotic disease in these subjects is warranted. The antiphospholipid syndrome is a common acquired prothrombotic condition, defined by a combination of thrombotic events and/or obstetric morbidity and positivity of specific antiphospholipid antibodies. Available information on antiphospholipid antibodies in dysglycaemia is scarce.

OBJECTIVE

This study investigates the association between antiphospholipid antibodies and dysglycaemia.

PATIENTS/METHODS

The PAROKRANK (periodontitis and its relation to coronary artery disease) study included 805 patients, investigated 6-10 weeks after a first myocardial infarction, and 805 matched controls. Participants without known diabetes (91%) underwent an oral glucose tolerance test. Associations between antiphospholipid antibodies (anti-cardiolipin and anti-β2 glycoprotein-I IgG, IgM and IgA) and dysglycaemia were analysed.

RESULTS

In total, 137 (9%) subjects had previously known type 2 diabetes and 371 (23%) newly diagnosed dysglycaemia. Compared with the normoglycaemic participants, those with dysglycaemia had a higher proportion with first myocardial infarction (61% vs 45%, p < 0.0001) and were more often antiphospholipid antibody IgG positive (8% vs 5%; p = 0.013). HbA1c, fasting glucose and 2-h glucose were significantly associated to antiphospholipid antibody IgG. Odds ratios (ORs) were 1.04 (95% confidence interval [CI] 1.02-1.06), 1.14 (95% CI 1.00 - 1.27) and 1.12 (95% CI 1.04 - 1.21), respectively, after adjustments for age, gender and smoking.

CONCLUSIONS

This study reports an association between antiphospholipid antibody IgG positivity and dysglycaemia. Further studies are needed to verify these findings and to investigate if antithrombotic therapy reduces vascular complications in antiphospholipid antibody positive subjects with dysglycaemia.

Myricetin, the Main Flavonoid in Syzygium cumini Leaf, Is a Novel Inhibitor of Platelet Thiol Isomerases PDI and ERp5

BACKGROUND

Flavonoids have been characterized as a prominent class of compounds to treat thrombotic diseases through the inhibition of thiol isomerases. Syzygium cumini is a flavonoid-rich medicinal plant that contains myricetin and gallic acid. Little is known about the potential antiplatelet properties of S. cumini and its constituent flavonoids.

OBJECTIVE

To evaluate the antiplatelet effects and mechanism of action of a polyphenol-rich extract (PESc) from S. cumini leaf and its most prevalent polyphenols, myricetin and gallic acid.

METHODS

PESc, myricetin, and gallic acid were incubated with platelet-rich plasma and washed platelets to assess platelet aggregation and activation. In vitro platelet adhesion and thrombus formation as well as in vivo bleeding time were performed. Finally, myricetin was incubated with recombinant thiol isomerases to assess its potential to bind and inhibit these, while molecular docking studies predicted possible binding sites.

RESULTS

PESc decreased platelet activation and aggregation induced by different agonists. Myricetin exerted potent antiplatelet effects, whereas gallic acid did not. Myricetin reduced the ability of platelets to spread on collagen, form thrombi in vitro without affecting hemostasis in vivo. Fluorescence quenching studies suggested myricetin binds to different thiol isomerases with similar affinity, despite inhibiting only protein disulfide isomerase (PDI) and ERp5 reductase activities. Finally, molecular docking studies suggested myricetin formed non-covalent bonds with PDI and ERp5.

CONCLUSIONS

PESc and its most abundant flavonoid myricetin strongly inhibit platelet function. Additionally, myricetin is a novel inhibitor of ERp5 and PDI, unveiling a new therapeutic perspective for the treatment of thrombotic disorders.

Incidence of Delayed Bleeding among Patients Continuing Antithrombotics during Gastric Endoscopic Submucosal Dissection

objective In patients continuing antithrombotics, delayed bleeding after gastric endoscopic submucosal dissection (ESD) is a severe complication. Vonoprazan (VPZ) exerts a rapid, potent, and long-lasting antacid effect compared with traditional proton-pump inhibitors (PPIs). This study aimed to compare the incidence of delayed bleeding after gastric ESD between the use of VPZ and PPIs in patients continuing antithrombotics. Methods In this retrospective analysis, we examined 71 patients with 101 lesions treated with traditional PPIs (PPI group) and 59 patients with 90 lesions treated with VPZ (VPZ group). After 2 days (day 0 and 1) of intravenous PPI administration, either an oral PPI or VPZ was administered from postoperative day 2 to 8 weeks after ESD. We assessed the incidence of overall delayed bleeding as well as bleeding that occurred from day 2 until 8 weeks after ESD. Results There was no significant difference in the use of antithrombotic agents between the groups. Overall delayed bleeding occurred 13 times (18%) in 9 patients in the PPI group and 18 times (31%) in 17 patients in the VPZ group (p=0.10). Bleeding from day 2 until 8 weeks after ESD occurred 12 times (17%) in 9 patients in the PPI group and 8 times (14%) in 8 patients in the VPZ group. Conclusion Even with a potent antacid agent, such as VPZ, the incidence of delayed bleeding was high in patients undergoing ESD with continuous antithrombotic agents.

Nattokinase: A Promising Alternative in Prevention and Treatment of Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death in the world and our approach to the control and management of CVD mortality is limited. Nattokinase (NK), the most active ingredient of natto, possesses a variety of favourable cardiovascular effects and the consumption of Natto has been linked to a reduction in CVD mortality. Recent research has demonstrated that NK has potent fibrinolytic activity, antihypertensive, anti-atherosclerotic, and lipid-lowering, antiplatelet, and neuroprotective effects. This review covers the major pharmacologic effects of NK with a focus on its clinical relevance to CVD. It outlines the advantages of NK and the outstanding issues pertaining to NK pharmacokinetics. Available evidence suggests that NK is a unique natural compound that possesses several key cardiovascular beneficial effects for patients with CVD and is therefore an ideal drug candidate for the prevention and treatment of CVD. Nattokinase is a promising alternative in the management of CVD.

Periprocedural Antithrombotic Treatment During Acute Mechanical Thrombectomy for Ischemic Stroke: A Systematic Review

BACKGROUND

More than one-third of the patients with ischemic stroke caused by an intracranial large vessel occlusion do not recover to functional independence despite fast and successful recanalization by acute mechanical thrombectomy (MT). This may partially be explained by incomplete microvascular reperfusion. Some antithrombotics, e.g., antiplatelet agents and heparin, may be able to restore microvascular reperfusion. However, antithrombotics may also increase the risk of symptomatic intracranial hemorrhage (sICH). The aim of this review was to assess the potential safety and functional outcome of periprocedural antiplatelet or heparin use during acute MT for ischemic stroke.

METHODS

We systematically searched PubMed, Embase, Medline, Web of Science, and Cochrane for studies investigating the safety and functional outcome of periprocedural antiplatelet or heparin treatment during acute MT for ischemic stroke. The primary outcome was the risk for sICH. Secondary outcomes were functional independence after 3-6 months (modified Rankin Scale 0-2) and mortality within 6 months.

RESULTS

837 studies were identified through the search, of which 19 studies were included. The sICH risks of the periprocedural use of antiplatelets ranged from 6 to 17%, and for heparin from 5 to 12%. Two of four studies reporting relative effects of the use of antithrombotics are pointing toward an increased risk of sICH. Among patients treated with antiplatelet agents, functional independence varied from 23 to 60% and mortality from 18 to 33%. For heparin, this was, respectively, 19-54% and 19-33%. The three studies presenting relative effects of antiplatelets on functional independence showed neutral effects. Both studies reporting relative effects of heparin on functional independence found it to increase this chance.

CONCLUSION

Randomized controlled trials investigating the effect of periprocedural antithrombotic treatment in MT are lacking. Some observational studies report a slight increase in sICH risk, which may be acceptable because they also suggest a beneficial effect on functional outcome. Therefore, randomized controlled trials are warranted to address the question whether the potentially higher risk of sICH could be outweighed by improved functional outcome.

A promising oral fucoidan-based antithrombotic nanosystem: Development, activity and safety

Fucoidan-loaded nanoparticles emerge as great candidates to oral anticoagulant therapy, due to increasing of bioavailability and circulation time of this natural anticoagulant. Crosslink between chitosan chains are performed using glutaraldehyde to confer higher gastric pH resistance to nanoparticle matrices. In this work, chitosan-fucoidan nanoparticles, without (NpCF) and with glutaraldehyde crosslink (NpCF 1% and NpCF 2%), were prepared to evaluate their anticoagulant, antithrombotic and hemorrhagic profile. Nanoparticles were characterized by average diameter, polydispersity index, zeta potential, Fourier transform infrared spectroscopy and fucoidan in vitro release. Anticoagulant and antithrombotic activities were determined by in vitro and in vivo models, respectively. Hemorrhagic profile was in vivo evaluated by tail bleeding assay. Preparations showed nanometric and homogeneous average diameters. Zeta potentials of NpCF and NpCF 1% were stable over gastrointestinal pH range, which was confirmed by low fucoidan release in gastric and enteric media. In pH 7.4, NpCF and NpCF 1% demonstrated fucoidan release of 65.5% and 60.6%, respectively, within the first 24 hours. In comparison to fucoidan, NpCF and NpCF 1% showed increased in vitro anticoagulant activity. A significant difference on oral antithrombotic profile of NpCF 1% was found in comparison to fucoidan. Bleeding profile of NpCF and NpCF 1% showed no differences to control group, indicating the safety of these systems. Surprisingly, oral antithrombotic profile of commercially available fucoidan, from Fucus vesiculosus, has not been previously determined, which reveals new possibilities. In this work, significant advances were observed in anticoagulant and antithrombotic profiles of fucoidan through the preparation of NpCF 1%.

[SAFETY AND EFFICACY OF CONTINUOUS ADMINISTRATION OF ANTITHROMBOTIC DRUGS DURING TRANSURETHRAL RESECTION OF BLADDER TUMORS]

(Objectives) We evaluated the safety and efficacy of continuous administration of antithrombotic drugs during transurethral resection of bladder tumors (TURBT). (Methods) We performed a retrospective review of 351 TURBT procedures performed at our institute from April 2011 to October 2015. Among these, antithrombotic drugs were continued in 31 TURBT cases throughout their perioperative period (continuation group), antithrombotic drugs were discontinued in 26 TURBT cases (discontinuation group), and bridging anticoagulation therapy with heparin after interruption of antithrombotic drugs was performed in 4 TURBT cases (heparin bridging group). The safety and efficacy of continuous administration of antithrombotic drugs during TURBT was evaluated by comparing the rate of perioperative complications, median operative time, duration of hematuria, urethral catheter placement, duration of stay after surgery, and by comparing the duration of stay among the three groups. (Results) The median operative time was 40.0 min in the continuation group, 39.0 min in the discontinuation group, and 31.0 min in the heparin bridging group with no significant differences. There were no significant differences in the median duration of hematuria (1.00 days vs. 1.00 days vs. 1.00 days), urethral catheter placement (3.00 days vs. 2.50 days vs. 2.00 days), or stay after TURBT (4.00 days vs. 3.50 days vs. 3.00 days) among the continuation, discontinuation, and heparin bridging groups. The median duration of stay was 6.00 days in the continuation group, 7.00 days in the discontinuation group, and 16.0 days in the heparin bridging group with significant differences between the continuation group vs. the heparin bridging group and the discontinuation group vs. the heparin bridging group. The rate of complications was 6 (19.4%) in the continuation group and 3 (11.5%) in the discontinuation group with no significant differences. However, a serious complication, cerebral infarction leading to hemiplegia, occurred in the discontinuation group. (Conclusion) Continuous administration of antithrombotic drugs during TURBT is considered to be safe and useful because it may prevent serious thromboembolism without adversely affecting the perioperative course.

Curcumin, hemostasis, thrombosis, and coagulation

Atherothrombotic cardiovascular disease is a major cause of mortality throughout the world. Platelet activation and aggregation play a central role in hemostasis and thrombosis. Herbal medicines have been traditionally used in the management of cardiovascular disease and can help in modifying its progression, particularly in hemostasis and the coagulation process, as well as altering platelet function tests and some coagulation parameters. Curcumin is a polyphenol derived from the Curcuma longa plant and has been used extensively in complementary and alternative medicine, as it is nontoxic and safe with various therapeutic properties. Modern scientific research has demonstrated its anti-inflammatory, antioxidant, anti-carcinogenic, antithrombotic, and cardiovascular protective effects. The present study reviewed previous studies in the literature, which support the positive activity of curcumin in hemostasis, anticoagulation, and fibrinolysis. We also presented molecular mechanisms associated with the antiplatelet and anticoagulant activities of curcumin and potential implications for the treatment of cardiovascular disease.

Long-term follow-up of antithrombotic management patterns in patients with acute coronary syndrome in Russia: an observational study (EPICOR-RUS study)

OBJECTIVE

This study sought to describe the short- and long-term (up to 2 years) antithrombotic management patterns in a real-life setting for patients hospitalized for an acute coronary syndrome (ACS) event, and to document clinical outcomes.

RESEARCH DESIGN AND METHODS

EPICOR-RUS was a multicenter (34 centers), prospective, observational, longitudinal cohort study conducted across Russia on antithrombotic management in hospitalized (within 24 hours of symptom onset) ACS patients with 2 year follow-up.

CLINICAL TRIAL REGISTRATION

NCT01373957.

RESULTS

A total of 600 ACS patients (71.1% male, mean age 60 years) were enrolled; 599 were included for analysis. Diagnosis comprised STEMI (n = 375, 62.6%), NSTEMI (n = 147, 24.5%), and unstable angina (UA) (n = 77, 12.9%). Percutaneous coronary intervention (PCI) was conducted in 64.3% of patients with STEMI (with or without thrombolysis), 36.7% with NSTEMI, and 58.4% with UA. There was undertreatment with dual antiplatelet therapy (DAPT) for STEMI, NSTEMI, and UA: 14.7%, 25.9% and 16.9% of patients, respectively, were not receiving DAPT during hospitalization, and 10.1%, 21.8% and 16.9% at discharge. Post-discharge, of the STEMI group, only 72.4% of patients who were managed by PCI and 39.8% of conservatively treated patients received DAPT at 12 months. The respective figures in the NSTEMI group were 77.3% and 26.4%. In the STEMI cohort the cumulative incidence of all-cause mortality was 3.2% at 1 year and 5.1% at 2 years of follow-up; in the NSTEMI cohort this was 2.7% and 4.8%, respectively. There were no deaths by 12 months and one death by 24 months (1.3%) in the UA population.

CONCLUSION

Despite evidence-based guidelines for the management of ACS, the real-world setting in Russia shows discrepancies in clinical practice, highlighting the need for improvements for the optimal management of high-risk patients with ACS.

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.

Novel antiplatelet role for a protein disulfide isomerase-targeted peptide: evidence of covalent binding to the C-terminal CGHC redox motif

Essentials Inhibitors of protein disulfide isomerase (PDI) have been considered a new antithrombotic class. CxxC is a PDI-targeted peptide that has been previously shown to inhibit its reductase activity. CxxC binds to surface PDI and inhibits ADP- and thrombin-evoked platelet activation and aggregation. CxxC binds to Cys400 on CGHC redox motif of PDI a' domain, a site for PDI prothrombotic activity.

SUMMARY

Background Protein disulfide isomerase (PDI) plays a major role in platelet aggregation, and its inhibitors have emerged as novel antithrombotic drugs. In previous work, we designed a peptide based on a PDI redox motif (CGHC) that inhibited both PDI reductase activity and PDI-modulated superoxide generation by neutrophil Nox2. Thus, we hypothesized that this peptide would also inhibit platelet aggregation by association with surface PDI. Methods Three peptides were used: CxxC, containing the PDI redox motif; Scr, presenting a scrambled sequence of the same residues and AxxA, with cysteines replaced by alanine. These peptides were tested under platelet aggregation and flow cytometry protocols to identify their possible antiplatelet activity. We labeled membrane free thiol and electrospray ionization liquid chromatography tandem mass spectrometry to test for an interaction. Results CxxC decreased platelet aggregation in a dose-dependent manner, being more potent at lower agonist concentrations, whereas neither AxxA nor Scr peptides exerted any effect. CxxC decreased aIIbb3 activation, but had no effect on the other markers. CxxC also decreased cell surface PDI pulldown without interfering with the total thiol protein content. Finally, we detected the addition of one CxxC molecule to reduced PDI through binding to Cys400 through mass spectrometry. Interestingly, CxxC did not react with oxidized PDI. Discussion CxxC has consistently shown its antiplatelet effects, both in PRP and washed platelets, corroborated by decreased aIIbb3 activation. The probable mechanism of action is through a mixed dissulphide bond with Cys400 of PDI, which has been shown to be essential for PDI's actions. Conclusion In summary, our data support antiplatelet activity for CxxC through binding to Cys400 in the PDI a0 domain, which can be further exploited as a model for sitedriven antithrombotic agent development.

[Management of antithrombotic agents for endoscopic procedures in elderly Chinese patients: a retrospective study]

OBJECTIVE

To investigate the peri-endoscopic management of antithrombotic drugs and adverse events in elderly patients un-dergoing gastrointestinal endoscopy in order to provide clinical guidance of peri-endoscopic management of antithrombotic drugs for elderly pa-tients.

METHODS

Between January 1^st 2008 and December 31^st 2014, clinical data of 3 747 patients (aged 46~99 years, 96.1% male) who were hospitalized for elective gastrointestinal endoscopy were analyzed retrospectively. The general clinical data, cardiovascular disease and re-lated risk factors, medication, management of peri-endoscopic antithrombotics and adverse events were recorded. The differences of peri-endo-scopic adverse events including thromboembolism and bleeding between patients with different management strategies of peri-endoscopic an-tithrombotics were analyzed.

RESULTS

The overall incidences of peri-endoscopic thromboembolism and bleeding were 2.24% and 1.89%, re-spectively. The incidences of thromboembolism and bleeding when stopping antithrombotics at 0~7 days pre-procedure were 1.87% and 2.38% respectively. The incidences of thromboembolism and bleeding when resuming antithrombotics at 2~7 days after endoscopy were 2.07% and 0.63% respectively. When discontinuing antithrombotics, the differences in peri-endoscopic thromboembolism and bleding be-tween patients who did and did not undergo low-molecular-weight heparin (LMWH) bridging therapy were not significant. The incidence of bleeding in patients who underwent LMWH bridging therapy was higher than that in patients who didn't undergo LMWH bridging therapy, but the diference was not significant.

CONCLUSIONS

Our findings suggest that cessation of antithrombotics < 7 days pre-procedures and resumption of antithrombotic agents after 2-7 days post-porcedures is optimal in elderly Chinese patients undergoing endoscopy.

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.

Perioperative complications following preoperative cessation of antithrombotic agents for total knee arthroplasty: A retrospective study

The number of elderly patients undergoing total knee arthroplasty (TKA) has steadily increased. Elderly patients undergoing TKA usually have underlying diseases, and some of them take antithrombotic agents for the prevention or treatment of these co-morbidities, including cardiovascular, cerebrovascular, or thromboembolic diseases. When these patients are scheduled to undergo TKA, preoperative cessation of antithrombotic agents is considered on the basis of its risks and benefits. This study was aimed to evaluate the impact of discontinuing antithrombotic agents for primary total knee arthroplasty (TKA) on perioperative complications.Patients who underwent primary TKA between 2008 and 2012 were identified, and classified into two groups: group A, in whom antithrombotic agents were ceased preoperatively, and group B, in which patients did not receive antithrombotic therapy. Patient characteristics, history of antithrombotic therapy, intraoperative blood loss, perioperative blood transfusion, postoperative 30-day complications, and postoperative hospital stay were recorded.Of 885 patients undergoing primary TKA, 218 (24.6%) patients were included in group A, and 667 (75.4%) in group B. Group A received transfusion more frequently than group B (P < 0.001). However, there was no difference between the two groups in terms of intraoperative blood loss, postoperative 30-day complications, and postoperative hospital stay.Patients who discontinued antithrombotic drugs before primary TKA do not have a higher incidence of postoperative 30-day complications, including cardiovascular, cerebrovascular, or thromboembolic events. Moreover, the estimated intraoperative blood loss was not different compared with patients not receiving antithrombotic agents preoperatively. Larger prospective studies of this issue are required.

Update on Brazilian biosimilar enoxaparins

INTRODUCTION

Brazil is among the first countries approving the commercialization and clinical use of biosimilar enoxaparins. Our research group has performed quality control assessments of these drugs over the last decade. Areas covered: We have not found noticeable differences between Brazilian biosimilar enoxaparins and the original product regarding their physicochemical properties, disaccharide composition, anticoagulant activity, bioavailability and safety. Expert commentary: In spite of clinical and pharmacological advantages of enoxaparin, subcutaneous formulations of unfractionated heparin are employed by the Brazilian public health system for prevention and treatment of thromboembolism. The underuse of both original and biosimilar enoxaparins in Brazil directly correlates with their high cost.

Left atrial appendage closure: A single center experience and comparison of two contemporary devices

OBJECTIVES

To compare indications and clinical outcomes of two contemporary left atrial appendage (LAA) percutaneous closure systems in a "real-world" population.

BACKGROUND

Percutaneous LAA occlusion is an emerging therapeutic option for stroke prevention in atrial fibrillation. Some questions however remain unanswered, such as the applicability of results of randomized trials to current clinical practice. Moreover, currently available devices have never been directly compared.

METHODS

We retrospectively analyzed consecutive patients who underwent LAA closure at San Raffaele Hospital, Milan, Italy between 2009 and 2015. Clinical indications and device selection were left to operators' decision; routine clinical and transesophageal echocardiography (TEE) follow-up was performed.

RESULTS

One-hundred and sixty-five patients were included in the study, of which 99 were treated with the Amplatzer Cardiac Plug (ACP) and 66 with the Watchman system. During the follow-up period (median 15 months, interquartile range 6-26 months) five patients died. The incidence of ischemic events was low, with one patient suffering a transient ischemic attack and no episodes recorded of definitive strokes. Twenty-six leaks ≥1 mm were detected (23%); leaks were less common with the ACP and with periprocedural three-dimensional TEE evaluation, but were not found to correlate with clinical events. Clinical outcomes were comparable between the two devices.

CONCLUSIONS

Our data show excellent safety and efficacy of LAA closure, irrespectively of the device utilized, in a population at high ischemic and hemorrhagic risk. The use of ACP and 3D-TEE minimized the incidence of residual leaks; however, the clinical relevance of small peri-device flow warrants further investigation. © 2016 Wiley Periodicals, Inc.

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.

Advanced age and high-residual platelet reactivity in patients receiving dual antiplatelet therapy with clopidogrel or ticagrelor

ESSENTIALS: Dual antiplatelet therapy (DAPT) in elderly patients requires balancing bleedings and thrombosis. Impact of age on high residual on-treatment platelet reactivity (HRPR) on DAPT was studied. A reduced effectiveness of adenosine diphosphate antagonists was observed over 70 years of age. The occurrence of HRPR was increased among elderly patients with both clopidogrel and ticagrelor.

BACKGROUND

The aim of the present study was to evaluate the impact of age on platelet function and the occurrence of high residual on-treatment platelet reactivity (HRPR) in patients treated with dual antiplatelet therapy (DAPT) using acetylsalicilic acid (ASA) and clopidogrel or ticagrelor.

METHODS

Patients treated with DAPT (ASA and clopidogrel or ticagrelor) were scheduled for platelet function assessment at 30-90 days post-discharge. By whole blood impedance aggregometry, HRPR was considered for ASPI test values > 862 AU*min (for ASA) and adenosine diphosphate (ADP) test values > 417 AU*min (for ADP antagonists). Elderly patients were defined as those aged ≥ 70 years.

RESULTS

Among 494 patients on DAPT, 224 (45.3%) were ≥ 70 years old. ADP-mediated platelet aggregation increased with decades of age (279.3 ± 148.6 vs. 319.6 ± 171.1 vs. 347.3 ± 190.1 vs. 345.7 ± 169.2), whereas no difference was observed for ASA response. A reduced effectiveness of ADP antagonists was observed among elderly patients; in fact, among the 117 patients displaying HRPR (23.7%), a higher prevalence was observed among patients over 70 years old (30.4% vs. 18.1%; adjusted odds ratio (OR) [95% confidence interval (CI)] = 2.19 [1.29-3.71]). Similar results were obtained among the 266 clopidogrel-treated patients (38.5% vs. 27.9%; adjusted OR [95% CI] = 2.91 [1.46-5.8]) and in the 228 patients receiving ticagrelor (19.1% vs. 8.1%; adjusted OR [95% CI] = 2.55 [1.02-8.59]).

CONCLUSION

In patients receiving dual antiplatelet therapy, advanced age is independently associated with a reduced effectiveness of ADP antagonists and a higher rate of HRPR with both clopidogrel and ticagrelor.

Design, green synthesis and pharmacological evaluation of novel 5,6-diaryl-1,2,4-triazines bearing 3-morpholinoethylamine moiety as potential antithrombotic agents (.)

The aim of this research work was to investigate a series of novel 5,6-diaryl-1,2,4-triazines (3a-3q) containing 3-morpholinoethylamine side chain, and to address their antiplatelet activity by in vitro, ex vivo and in vivo methods. All compounds were synthesized by environment benign route and their structures were unambiguously confirmed by spectral data. Compounds (3l) and (3m) were confirmed by their single crystal X-ray structures. Out of all the synthesized compounds, 10 were found to be more potent in vitro than aspirin; six of them were found to be prominent in ex vivo assays and one compound (3d) was found to have the most promising antithrombotic profile in vivo. Moreover, compound (3d) demonstrated less ulcerogenicity in rats as compared to aspirin. The selectivity of the most promising compound (3d) for COX-1 and COX-2 enzymes was determined with the help of molecular docking studies and the results were correlated with the biological activity.

Characterization of a novel function-blocking antibody targeted against the platelet P2Y1 receptor

OBJECTIVE

Platelet hyperactivity is associated with vascular disease and contributes to the genesis of thrombotic disorders. ADP plays an important role in platelet activation and activates platelets through 2 G-protein-coupled receptors, the Gq-coupled P2Y1 receptor (P2Y1R), and the Gi-coupled P2Y12 receptor. Although the involvement of the P2Y1R in thrombogenesis is well established, there are no antagonists that are currently available for clinical use.

APPROACH AND RESULTS

Our goal is to determine whether a novel antibody targeting the ligand-binding domain, ie, second extracellular loop (EL2) of the P2Y1R (EL2Ab) could inhibit platelet function and protect against thrombogenesis. Our results revealed that the EL2Ab does indeed inhibit ADP-induced platelet aggregation, in a dose-dependent manner. Furthermore, EL2Ab was found to inhibit integrin GPIIb-IIIa activation, dense and α granule secretion, and phosphatidylserine exposure. These inhibitory effects translated into protection against thrombus formation, as evident by a prolonged time for occlusion in a FeCl3-induced thrombosis model, but this was accompanied by a prolonged tail bleeding time. We also observed a dose-dependent displacement of the radiolabeled P2Y1R antagonist [(3)H]MRS2500 from its ligand-binding site by EL2Ab.

CONCLUSIONS

Collectively, our findings demonstrate that EL2Ab binds to and exhibits P2Y1R-dependent function-blocking activity in the context of platelets. These results add further evidence for a role of the P2Y1R in thrombosis and validate the concept that targeting it is a relevant alternative or complement to current antiplatelet strategies.

Amiodarone, anticoagulation, and clinical events in patients with atrial fibrillation: insights from the ARISTOTLE trial

BACKGROUND

Amiodarone is an effective medication in preventing atrial fibrillation (AF), but it interferes with the metabolism of warfarin.

OBJECTIVES

This study sought to examine the association of major thrombotic clinical events and bleeding with the use of amiodarone in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial.

METHODS

Baseline characteristics of patients who received amiodarone at randomization were compared with those who did not receive amiodarone. The interaction between randomized treatment and amiodarone was tested using a Cox model, with main effects for randomized treatment and amiodarone and their interaction. Matching on the basis of a propensity score was used to compare patients who received and who did not receive amiodarone at the time of randomization.

RESULTS

In ARISTOTLE, 2,051 (11.4%) patients received amiodarone at randomization. Patients on warfarin and amiodarone had time in the therapeutic range that was lower than patients not on amiodarone (56.5% vs. 63.0%; p < 0.0001). More amiodarone-treated patients had a stroke or a systemic embolism (1.58%/year vs. 1.19%/year; adjusted hazard ratio [HR]: 1.47, 95% confidence interval [CI]: 1.03 to 2.10; p = 0.0322). Overall mortality and major bleeding rates were elevated, but were not significantly different in amiodarone-treated patients and patients not on amiodarone. When comparing apixaban with warfarin, patients who received amiodarone had a stroke or a systemic embolism rate of 1.24%/year versus 1.85%/year (HR: 0.68, 95% CI: 0.40 to 1.15), death of 4.15%/year versus 5.65%/year (HR: 0.74, 95% CI: 0.55 to 0.98), and major bleeding of 1.86%/year versus 3.06%/year (HR: 0.61, 95% CI: 0.39 to 0.96). In patients who did not receive amiodarone, the stroke or systemic embolism rate was 1.29%/year versus 1.57%/year (HR: 0.82, 95% CI: 0.68 to 1.00), death was 3.43%/year versus 3.68%/year (HR: 0.93, 95% CI: 0.83 to 1.05), and major bleeding was 2.18%/year versus 3.03%/year (HR: 0.72, 95% CI: 0.62 to 0.84). The interaction p values for amiodarone use by apixaban treatment effects were not significant.

CONCLUSIONS

Amiodarone use was associated with significantly increased stroke and systemic embolism risk and a lower time in the therapeutic range when used with warfarin. Apixaban consistently reduced the rate of stroke and systemic embolism, death, and major bleeding compared with warfarin in amiodarone-treated patients and patients who were not on amiodarone.

Variation in restarting antithrombotic drugs at hospital discharge after intracerebral hemorrhage

BACKGROUND AND PURPOSE

Whether intracerebral hemorrhage (ICH) survivors should restart antithrombotic drugs is unknown. We analyzed the frequency of restarting antithrombotic drugs in ICH survivors who had taken prophylactic antithrombotic drugs in atrial fibrillation or after thromboembolic disease in 5 cohorts and explored factors associated with doing so.

METHODS

We compared the characteristics and proportions of patients taking antithrombotic drugs at ICH onset and discharge in 4 hospital-based cohorts (Lille, France, n=542; Utrecht, The Netherlands, n=389; multicenter Clinical Relevance of Microbleeds in Stroke-2 (CROMIS-2) ICH, United Kingdom, n=667; and Amsterdam, The Netherlands, n=403) and 1 community-based study (Lothian, Scotland, n=137), using bivariate analyses. We sought characteristics associated with restarting using bivariate and multivariable logistic regression analyses.

RESULTS

A total of 942 (44%) patients with ICH took antithrombotic drugs at hospital admission (no difference between cohorts). Antithrombotic drugs were restarted in 96 (20%) of the 469 survivors who had taken antithrombotic drugs for secondary prevention or atrial fibrillation, but this proportion differed when stratified by the cohort of origin (Lille, 18%; Utrecht, 45%; Lothian, 15%; CROMIS-2 ICH, 11%; Amsterdam, 20%; P<0.001) and by type of antithrombotic drug pre-ICH (14% in patients with previous antiplatelet drugs versus 26% in patients with previous vitamin K antagonists and 41% in patients with both drugs; P<0.001). We did not find other consistent, independent associations with restarting antithrombotic drugs.

CONCLUSIONS

The variation in clinical practice and lack of consistent associations with restarting antithrombotic drugs after ICH reflect current knowledge and support the need for randomized controlled trials to resolve this dilemma.

Thiol isomerases in thrombus formation

Protein disulfide isomerase (PDI), ERp5, and ERp57, among perhaps other thiol isomerases, are important for the initiation of thrombus formation. Using the laser injury thrombosis model in mice to induce in vivo arterial thrombus formation, it was shown that thrombus formation is associated with PDI secretion by platelets, that inhibition of PDI blocked platelet thrombus formation and fibrin generation, and that endothelial cell activation leads to PDI secretion. Similar results using this and other thrombosis models in mice have demonstrated the importance of ERp5 and ERp57 in the initiation of thrombus formation. The integrins, αIIbβ3 and αVβ3, play a key role in this process and interact directly with PDI, ERp5, and ERp57. The mechanism by which thiol isomerases participate in thrombus generation is being evaluated using trapping mutant forms to identify substrates of thiol isomerases that participate in the network pathways linking thiol isomerases, platelet receptor activation, and fibrin generation. PDI as an antithrombotic target is being explored using isoquercetin and quercetin 3-rutinoside, inhibitors of PDI identified by high throughput screening. Regulation of thiol isomerase expression, analysis of the storage, and secretion of thiol isomerases and determination of the electron transfer pathway are key issues to understanding this newly discovered mechanism of regulation of the initiation of thrombus formation.

Antiplatelet therapy for stable coronary artery disease in atrial fibrillation patients taking an oral anticoagulant: a nationwide cohort study

BACKGROUND

The optimal long-term antithrombotic treatment of patients with coexisting atrial fibrillation and stable coronary artery disease is unresolved, and commonly, a single antiplatelet agent is added to oral anticoagulation. We investigated the effectiveness and safety of adding antiplatelet therapy to vitamin K antagonist (VKA) in atrial fibrillation patents with stable coronary artery disease.

METHODS AND RESULTS

Atrial fibrillation patients with stable coronary artery disease (defined as 12 months from an acute coronary event) between 2002 and 2011 were identified. The subsequent risk of cardiovascular events and serious bleeding events (those that required hospitalization) was examined with adjusted Cox regression models according to ongoing antithrombotic therapy. A total of 8700 patients were included (mean age, 74.2 years; 38% women). During a mean follow-up of 3.3 years, crude incidence rates were 7.2, 3.8, and 4.0 events per 100 person-years for myocardial infarction/coronary death, thromboembolism, and serious bleeding, respectively. Relative to VKA monotherapy, the risk of myocardial infarction/coronary death was similar for VKA plus aspirin (hazard ratio, 1.12 [95% confidence interval, 0.94-1.34]) and VKA plus clopidogrel (hazard ratio, 1.53 [95% confidence interval, 0.93-2.52]). The risk of thromboembolism was comparable in all regimens that included VKA, whereas the risk of bleeding increased when aspirin (hazard ratio, 1.50 [95% confidence interval, 1.23-1.82]) or clopidogrel (hazard ratio, 1.84 [95% confidence interval, 1.11-3.06]) was added to VKA.

CONCLUSIONS

In atrial fibrillation patients with stable coronary artery disease, the addition of antiplatelet therapy to VKA therapy is not associated with a reduction in risk of recurrent coronary events or thromboembolism, whereas risk of bleeding is increased significantly. The common practice of adding antiplatelet therapy to oral VKA anticoagulation in patients with atrial fibrillation and stable coronary artery disease warrants reassessment.

Is the antithrombotic effect of sulfated galactans independent of serpin?

BACKGROUND

Sulfated galactans are polysaccharides with heterogeneous structures that frequently show anticoagulant activity. Their anticoagulant mechanisms are complex and distinct from those observed for heparin. Sulfated galactans act through a combination of effects involving serpin-dependent and serpin-independent mechanisms. Interestingly, these polymers can also induce blood coagulation due to activation of factor XII (FXII).

OBJECTIVES

The structure of a complex sulfated galactan from the red alga Acanthophora muscoides was characterized by solution nuclear magnetic resonance. This polysaccharide and another previously characterized algal sulfated galactan from Botryocladia occidentalis were each used in in vitro and in vivo anticoagulant and antithrombotic assays to understand the possible structural determinants of their functional effects.

RESULTS AND CONCLUSIONS

The serpin-dependent anticoagulant effects and FXII-related procoagulant effects of the sulfated galactans decreased in parallel with the molecular size. The serpin-independent anticoagulation also correlated with the chemical structure of the sulfated galactans. The sulfated galactan from A. muscoides, which showed mostly serpin-independent anticoagulant activity and reduced activation of FXII, drastically reduced arterial thrombus formation. However, the sulfated galactans produced opposite effects on venous thrombosis; this difference appears to result from the tenuous balance between the various effects on coagulation, including serpin-dependent and serpin-independent anticoagulation and FXIIa-dependent procoagulation. This study of novel sulfated polysaccharides with distinct effects on coagulation and thrombosis helps to establish the minimal structural-function relationship required for the development of antithrombotic drugs.