The antithrombotic profile of aspirin. Aspirin resistance, or simply failure?

Sustained intestinal epithelial monolayer wound closure after transient application of a FAK-activating small molecule

M64HCl, which has drug-like properties, is a water-soluble Focal Adhesion Kinase (FAK) activator that promotes murine mucosal healing after ischemic or NSAID-induced injury. Since M64HCl has a short plasma half-life in vivo (less than two hours), it has been administered as a continuous infusion with osmotic minipumps in previous animal studies. However, the effects of more transient exposure to M64HCl on monolayer wound closure remained unclear. Herein, we compared the effects of shorter M64HCl treatment in vitro to continuous treatment for 24 hours on monolayer wound closure. We then investigated how long FAK activation and downstream ERK1/2 activation persist after two hours of M64HCl treatment in Caco-2 cells. M64HCl concentrations immediately after washing measured by mass spectrometry confirmed that M64HCl had been completely removed from the medium while intracellular concentrations had been reduced by 95%. Three-hour and four-hour M64HCl (100 nM) treatment promoted epithelial sheet migration over 24 hours similar to continuous 24-hour exposure. 100nM M64HCl did not increase cell number. Exposing cells twice with 2-hr exposures of M64HCl during a 24-hour period had a similar effect. Both FAK inhibitor PF-573228 (10 μM) and ERK kinase (MEK) inhibitor PD98059 (20 μM) reduced basal wound closure in the absence of M64HCl, and each completely prevented any stimulation of wound closure by M64HCl. Rho kinase inhibitor Y-27632 (20 μM) stimulated Caco-2 monolayer wound closure but no further increase was seen with M64HCl in the presence of Y-27632. M64HCl (100 nM) treatment for 3 hours stimulated Rho kinase activity. M64HCl decreased F-actin in Caco-2 cells. Furthermore, a two-hour treatment with M64HCl (100 nM) stimulated sustained FAK activation and ERK1/2 activation for up to 16 and hours 24 hours, respectively. These results suggest that transient M64HCl treatment promotes prolonged intestinal epithelial monolayer wound closure by stimulating sustained activation of the FAK/ERK1/2 pathway. Such molecules may be useful to promote gastrointestinal mucosal repair even with a relatively short half-life.

Antithrombotic prophylaxis following total knee arthroplasty: a level I Bayesian network meta-analysis

INTRODUCTION

Venous thromboembolism (VTE) is a major concern following total knee arthroplasty (TKA). The optimal pharmacological prophylaxis remains, however, controversial. The present investigation compared several non-vitamin K antagonist oral anticoagulants commonly employed as VTE prophylaxis following TKA. A Bayesian network meta-analysis was conducted to compare apixaban, aspirin, dabigatran, edoxaban, enoxaparin, fondaparinux, and rivaroxaban. The outcomes of interest were to compare the rate of deep venous thrombosis (DVT), pulmonary embolism (PE), and major and minor haemorrhages.

METHODS

This study was conducted according to the PRISMA Extension Statement for Reporting of Systematic Reviews Incorporating Network Meta-Analyses of Health Care Interventions. In March 2024, PubMed, Web of Science, and Google Scholar were accessed with no time constraints. All randomised controlled trials (RCTs) comparing two or more drugs for the prevention of VTE following TKA were considered for inclusion.

RESULTS

Data from 29,678 patients were collected. Of them, 67% (19,884 of 29,678 patients) were women. The mean age of the patients was 66.8 ± 2.8 years, and the mean BMI was 29.2 ± 1.5 kg/m2. There was comparability in age, sex, and BMI at baseline. Apixaban 5 mg, dabigatran 220 mg, and rivaroxaban 10 mg were the most effective in reducing the rate of DVT. Apixaban 5 mg, enoxaparin 60 mg, and rivaroxaban 40 mg were the most effective in reducing the rate of PE. Apixaban 5 mg, rivaroxaban 10 mg, and apixaban 10 mg were associated with the lowest rate of major haemorrhages. Apixaban 5 mg and 20 mg, and dabigatran 220 mg were associated with the lowest rate of minor haemorrhages.

CONCLUSION

Administration of apixaban 5 mg demonstrated the best balance between VTE prevention and haemorrhage control following TKA.

LEVEL OF EVIDENCE

Level I, network meta-analysis of RCTs.

Metabolic, toxicological, chemical, and commercial perspectives on esterification of dietary polyphenols: a review

Molecular modifications have been practiced for more than a century and nowadays they are widely applied in food, pharmaceutical, or other industries to manipulate the physicochemical, bioactivity, metabolic/catabolic, and pharmacokinetic properties. Among various structural modifications, the esterification/O-acylation has been well-established in altering lipophilicity and bioactivity of parent bioactive compounds, especially natural polyphenolics, while maintaining their high biocompatibility. Meanwhile, various classic chemical and enzymatic protocols and other recently emerged cell factory technology are being employed as viable esterification strategies. In this contribution, the main motivations of phenolic esterification, including the tendency to replace synthetic alkyl phenolics with safer alternatives in the food industry to improve the bioavailability of phenolics as dietary supplements/pharmaceuticals, are discussed. In addition, the toxicity, metabolism, and commercial application of synthetic and natural phenolics are briefly introduced. Under these contexts, the mechanisms and reaction features of several most prevalent chemical and enzymatic esterification pathways are demonstrated. In addition, insights into the studies of esterification modification of natural phenolic compounds and specific pros/cons of various reaction systems with regard to their practical application are provided.

Direct Oral Anticoagulant Treatment for Atherosclerosis-Induced Aortic Mural Thrombus in an Elderly Male With Aspirin Resistance

Aortic mural thrombus is associated with atherosclerosis in a vast majority of cases and could result in multiple organ damage, leading to higher morbidity and mortality rates. Although aspirin could be effective for primary prevention in atherosclerosis-induced aortic mural thrombus, aspirin resistance, which refers to the inadequate response to aspirin therapy, allows the progression of thrombus. Classically, warfarin could be an effective treatment for thromboembolic diseases, while in recent years, direct oral anticoagulants (DOACs) have shown superior safety and efficacy, particularly in elderly patients. This report presents the case of an elderly male with chronic aortic mural thrombi due to atherosclerosis and aspirin resistance who achieved favorable outcomes following treatment with DOACs. DOACs could be a possible option for managing aortic mural thrombus with aspirin resistance.

Haemorrhagic Complications After Microsurgical Treatment for Intracranial Aneurysms Under Acetylsalicylic Acid: An Impact Analysis

BACKGROUND

Patients with intracranial aneurysms often have comorbidities that require them to take acetylsalicylic acid (ASA). In recent years, many patients with aneurysms have been prescribed ASA to prevent aneurysm enlargement. ASA is also prescribed to patients with intracranial aneurysms in preparation for surgical revascularization.

METHODS

From 2016 to 2021, 64 patients underwent microsurgical aneurysm clipping without revascularization, and an additional 20 patients underwent extracranial to intracranial (EC-IC) bypass. The following parameters were analysed: the frequency of hemorrhagic complications, the blood loss volume, the duration of surgery and inpatient treatment, the change in hemoglobin level (Hb), hematocrit (Ht), erythrocytes, and clinical outcomes according to the modified Rankin scale (mRS).

RESULTS

At the time of surgery, laboratory-confirmed effect of the ASA was registered in 22 patients (main group). In 42 patients, the ASA was not functional on assay (control group). Hemorrhagic complications were noted in two patients in the ASA group. In both cases, the hemorrhagic component did not exceed 15 ml in volume and did not require additional surgical interventions. Statistical analysis showed no significant differences in hemorrhagic postoperative complications.

CONCLUSION

Taking low doses of acetylsalicylic acid during planned microsurgical clipping of cerebral aneurysms does not affect intraoperative blood loss volume, risk of postoperative hemorrhagic complications, length of stay in the hospital, or functional outcomes.

Evaluating thrombosis risk and patient-specific treatment strategy using an atherothrombosis-on-chip model

Platelets play an essential role in thrombotic processes. Recent studies suggest a direct link between increased plasma glucose, lipids, and inflammatory cytokines with platelet activation and aggregation, resulting in an increased risk of atherothrombotic events in cardiovascular patients. Antiplatelet therapies are commonly used for the primary prevention of atherosclerosis. Transitioning from a population-based strategy to patient-specific care requires a better understanding of the risks and advantages of antiplatelet therapy for individuals. This proof-of-concept study evaluates the potential to assess an individual's risk of forming atherothrombosis using a dual-channel microfluidic model emulating multiple atherogenic factors in vitro, including high glucose, high cholesterol, and inflammatory cytokines along with stenosis vessel geometry. The model shows precise sensitivity toward increased plasma glucose, cholesterol, and tumour necrosis factor-alpha (TNF-α)-treated groups in thrombus formation. An in vivo-like dose-dependent increment in platelet aggregation is observed in different treated groups, benefiting the evaluation of thrombosis risk in the individual condition. Moreover, the model could help decide the effective dosing of aspirin in multi-factorial complexities. In the high glucose-treated group, a 50 μM dose of aspirin could significantly reduce platelet aggregation, while a 100 μM dose of aspirin was required to reduce platelet aggregation in the glucose-TNF-α-treated group, which proves the model's potentiality as a tailored tool for customised therapy.

Cellular Components Contributing to the Development of Venous Thrombosis in Patients with Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive type of cancer and has a poor prognosis. Patients with PDAC are at high risk of developing thromboembolic events, which is a leading cause of morbidity and mortality following cancer progression. Plasma-derived coagulation is the most studied process in cancer-associated thrombosis. Other blood components, such as platelets, red blood cells, and white blood cells, have been gaining less attention. This narrative review addresses the literature on the role of cellular components in the development of venous thromboembolism (VTE) in patients with PDAC. Blood cells seem to play an important role in the development of VTE. Altered blood cell counts, i.e., leukocytosis, thrombocytosis, and anemia, have been found to associate with VTE risk. Tumor-related activation of leukocytes leads to the release of tissue factor-expressing microvesicles and the formation of neutrophil extracellular traps, initiating coagulation and forming a scaffold for thrombi. Tissue factor-expressing microvesicles are also thought to be released by PDAC cells. PDAC cells have been shown to stimulate platelet activation and aggregation, proposedly via the secretion of podoplanin and mucins. Hypofibrinolysis, partially explained by increased plasminogen activator inhibitor-1 activity, is observed in PDAC. In short, PDAC-associated hypercoagulability is a complex and multifactorial process. A better understanding of cellular contributions to hypercoagulability might lead to the improvement of diagnostic tests to identify PDAC patients at highest risk of VTE.

Antithrombotic prophylaxis following total hip arthroplasty: a level I Bayesian network meta-analysis

BACKGROUND

Several clinical investigations have compared different pharmacologic agents for the prophylaxis of venous thromboembolism (VTE). However, no consensus has been reached. The present investigation compared enoxaparin, fondaparinux, aspirin and non-vitamin K antagonist oral anticoagulants (NOACs) commonly used as prophylaxis following total hip arthroplasty (THA). A Bayesian network meta-analysis was performed, setting as outcomes of interest the rate of deep venous thrombosis (DVT), pulmonary embolism (PE) and major and minor haemorrhages.

METHODS

This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension statement for reporting systematic reviews incorporating network meta-analyses of healthcare interventions. All randomised controlled trials (RCTs) comparing two or more drugs used for the prophylaxis of VTE following THA were accessed. PubMed, Web of Science and Google Scholar databases were accessed in March 2023 with no time constraint.

RESULTS

Data from 31,705 patients were extracted. Of these, 62% (19,824) were women, with age, sex ratio, and body mass index (BMI) being comparable at baseline. Apixaban 5 mg, fondaparinux, and rivaroxaban 60 mg were the most effective in reducing the rate of DVT. Dabigatran 220 mg, apixaban 5 mg, and aspirin 100 mg were the most effective in reducing the rate of PE. Apixaban 5 mg, ximelagatran 2 mg and aspirin 100 mg were associated with the lowest rate of major haemorrhages, while rivaroxaban 2.5 mg, apixaban 5 mg and enoxaparin 40 mg were associated with the lowest rate of minor haemorrhages.

CONCLUSION

Administration of apixaban 5 mg demonstrated the best balance between VTE prevention and haemorrhage control following THA. Level of evidence Level I, network meta-analysis of RCTs.

Safety of surfactant excipients in oral drug formulations

Surfactants are a diverse group of compounds that share the capacity to adsorb at the boundary between distinct phases of matter. They are used as pharmaceutical excipients, food additives, emulsifiers in cosmetics, and as household/industrial detergents. This review outlines the interaction of surfactant-type excipients present in oral pharmaceutical dosage forms with the intestinal epithelium of the gastrointestinal (GI) tract. Many surfactants permitted for human consumption in oral products reduce intestinal epithelial cell viability in vitro and alter barrier integrity in epithelial cell monolayers, isolated GI tissue mucosae, and in animal models. This suggests a degree of mis-match for predicting safety issues in humans from such models. Recent controversial preclinical research also infers that some widely used emulsifiers used in oral products may be linked to ulcerative colitis, some metabolic disorders, and cancers. We review a wide range of surfactant excipients in oral dosage forms regarding their interactions with the GI tract. Safety data is reviewed across in vitro, ex vivo, pre-clinical animal, and human studies. The factors that may mitigate against some of the potentially abrasive effects of surfactants on GI epithelia observed in pre-clinical studies are summarised. We conclude with a perspective on the overall safety of surfactants in oral pharmaceutical dosage forms, which has relevance for delivery system development.

Proteomic analysis of lysine 2-hydroxyisobutyryl in SLE reveals protein modification alteration in complement and coagulation cascades and platelet activation Pathways

BACKGROUND

Post-translational modifications (PTMs) are considered to be an important factor in the pathogenesis of Systemic lupus erythematosus (SLE). Lysine 2-hydroxyisobutyryl (Khib), as an emerging post-translational modification of proteins, is involved in some important biological metabolic activities. However, there are poor studies on its correlation with diseases, especially SLE.

OBJECTIVE

We performed quantitative, comparative, and bioinformatic analysis of Khib proteins in Peripheral blood mononuclear cells (PBMCs) of SLE patients and PBMCs of healthy controls. Searching for pathways related to SLE disease progression and exploring the role of Khib in SLE.

METHODS

Khib levels in SLE patients and healthy controls were compared based on liquid chromatography tandem mass spectrometry, then proteomic analysis was conducted.

RESULTS

Compared with healthy controls, Khib in SLE patients was up-regulated at 865 sites of 416 proteins and down-regulated at 630 sites of 349 proteins. The site abundance, distribution and function of Khib protein were investigated further. Bioinformatics analysis showed that Complement and coagulation cascades and Platelet activation in immune-related pathways were significantly enriched, suggesting that differentially modified proteins among them may affect SLE.

CONCLUSION

Khib in PBMCs of SLE patients was significantly up- or down-regulated compared with healthy controls. Khib modification of key proteins in the Complement and coagulation cascades and Platelet activation pathways affects platelet activation and aggregation, coagulation functions in SLE patients. This result provides a new direction for the possible significance of Khib in the pathogenesis of SLE patients.

Pharmacokinetic Study of Enteric-Coated Sustained-Release Aspirin Tablets in Healthy Chinese Participants

Purpose

To study and compare the pharmacokinetic characteristics of enteric-coated sustained-release (EcSr) aspirin tablets with enteric-coated (Ec) aspirin tablets (Bayer S.p.A) in healthy Chinese participants.

Patients and Methods

In this open, randomized, single-dose, three-way, crossover study, 18 healthy participants randomly received 100 mg EcSr tablets pre-prandially (a.c.), EcSr tablets post-prandially (p.c.), or Ec tablets a.c. in each period. The concentrations of acetylsalicylic acid (ASA) and salicylic acid (SA) in plasma were determined by the LC-MS/MS method, and the pharmacokinetic parameters were calculated using WinNonlin (version 8.1).

Results

The essential PK parameters under the three treatment conditions (ie Ec a.c., EcSr a.c. and EcSr p.c.) were as follows: Cmax, ASA: 758.38±455.34, 222.77±98.04 and 194.54±61.19 ng, Tmax, ASA: 6.75(2,16), 4.5(2,11) and 8.25(5,11) h, T1/2, ASA: 0.43±0.08, 1.44±0.59 and 4.32±10.04 h, AUC0-t, ASA: 1008.88±452.27, 918.04±238.40 and 845.55±183.25 h·ng/mL; Cmax, SA: 6409.38±2098.52, 2863.53±679.73 and 2913.75±853.27ng/mL, Tmax, SA: 7.25(2,24), 10(3.5-14) and 10(7,14) h, T1/2, SA: 2.21±0.46, 2.69±0.72 and 3.51±2.06h, AUC0-t, SA: 29,131.41±9376.23, 27,243.97±7465.16, 27,240.25±7444.67 h·ng/mL. When taking EcSr aspirin tablets, the 90% confidence intervals of the geometric mean ratios (pre-prandial/post-prandial) of AUC0-t, ASA and AUC0-∞, ASA, Cmax, SA, AUC0-t, SA and AUC0-∞, SA were within the range of 80.00%-125.00%.

Conclusion

EcSr aspirin tablets showed less inter-individual variation in release and absorption than Ec aspirin tablets, which was well reflected by comparing essential PK parameters. Furthermore, meals had no significant effect on the pharmacokinetics of EcSr aspirin tablets.

Perioperative Management of Oral Anticoagulants and Antiplatelet Therapy in Hand and Wrist Surgery

There is wide variability in the management of patients on antithrombotic therapy requiring surgery of the hand and wrist. There are no specific guidelines regarding whether to temporarily cease or continue oral anticoagulants and antiplatelet agents. Discontinuation of these medications before surgery can lead to perioperative thromboembolic or ischemic events. On the other hand, continuation can lead to intraoperative or postoperative bleeding complications. This review discusses various anticoagulants and antiplatelet agents with special considerations for their management, analyzes the current literature, summarizes current recommendations, and provides direction for additional research.

Novel Antithrombotic Agents in Pregnancy Anticoagulants and Antiplatelet Agents

Increasing rates of thromboembolic complications have required increasing use of anticoagulant and antiplatelet agents during and after pregnancy. Furthermore, thromboembolism is both a cause and a complication of severe maternal morbidity requiring intensive care. As a consequence, almost all patients admitted to intensive care units receive an anticoagulant or an antiplatelet agent (or both) for either treatment or prevention of thromboembolism. In this review, we summarize commonly used anticoagulants and antiplatelet agents and outline the potential role of newly developed (novel) antithrombotic agents for pregnant and postpartum patients.

Management of encephalomyocarditis virus infection in Italian pig farms: a case report

BACKGROUND

Encephalomyocarditis virus (EMCV) has been isolated from many animals, frequently as the cause of fatal myocarditis, but pigs are the most susceptible domestic specie. The virus was isolated in swine farms since 1958 in Panama and Europe from cases of sudden death in young pigs, and the main origin of outbreaks has been assumed to be local rodent populations. There is no treatment for the disease.

CASE PRESENTATION

The clinical case describes an outbreak of encephalomyocarditis virus in a farrowing (farm A) and a weaning (farm B) site, with mortality that reached 24.2% in suckling piglets and 7.7% in weaners. The farms were located in an endemic Italian area, and the outbreak was characterised by high mortality with sudden death and clinical signs due to heart failure (trembling, dispnea and fever). The rodents control program was the key action in managing the outbreak. However, in the weaning site, the lack of rodent program in some unexplored areas of the barn (false ceiling) was responsible of a longer time of resolution of the outbreak. An unusual support treatment approach from human medicine suggestion was also applied using acetylsalicylic acid for its antiphlogistic and antithrombotic effects.

CONCLUSIONS

To control the rodent population in a pig farm is often difficult and requires a deep knowledge also of the rodents habits. Considering the lack of treatment for the disease and the absence of available vaccines in several Countries, acetylsalicylic acid might be of interest for further studies as an important support for pigs' recovery.

Acetylsalicylic Acid-Primus Inter Pares in Pharmacology

Acetylsalicylic acid (ASA) is one of the first drugs to be obtained by synthesis while being the most used. It has experienced the longest lasting commercial success and is considered the most popular drug of the modern era. ASA, originally used as an anti-inflammatory medication, nowadays is predominantly used as an antiplatelet agent for prophylaxis in cardiac patients. Many studies show that the benefits of using ASA far outweigh the potential risk of side effects. With particular emphasis on the possibility of ASA repositioning for new therapies, extending the indications for use beyond the diseases from the spectrum of atherosclerotic diseases, such as cancer, requires shifting the benefit-risk ratio, although very good, even more towards safety. Interesting activities consisting not only of changing the formulation but also modifying the drug molecule seem to be an important goal of the 21st century. ASA has become a milestone in two important fields: pharmacy and medicine. For a pharmacist, ASA is a long-used drug for which individual indications are practically maintained. For a doctor, acetylsalicylic acid is primarily an antiplatelet drug that saves millions of lives of patients with coronary heart disease or after a stroke. These facts do not exempt us from improving therapeutic methods based on ASA, the main goal of which is to reduce the risk of side effects, as well as to extend effectiveness. Modified acetylsalicylic acid molecules already seem to be a promising therapeutic option.

Platelet in thrombo-inflammation: Unraveling new therapeutic targets

In the broad range of human diseases, thrombo-inflammation appears as a clinical manifestation. Clinically, it is well characterized in context of superficial thrombophlebitis that is recognized as thrombosis and inflammation of superficial veins. However, it is more hazardous when developed in the microvasculature of injured/inflamed/infected tissues and organs. Several diseases like sepsis and ischemia-reperfusion can cause formation of microvascular thrombosis subsequently leading to thrombo-inflammation. Thrombo-inflammation can also occur in cases of antiphospholipid syndrome, preeclampsia, sickle cell disease, bacterial and viral infection. One of the major contributors to thrombo-inflammation is the loss of normal anti-thrombotic and anti-inflammatory potential of the endothelial cells of vasculature. This manifest itself in the form of dysregulation of the coagulation pathway and complement system, pathologic platelet activation, and increased recruitment of leukocyte within the microvasculature. The role of platelets in hemostasis and formation of thrombi under pathologic and non-pathologic conditions is well established. Platelets are anucleate cells known for their essential role in primary hemostasis and the coagulation pathway. In recent years, studies provide strong evidence for the critical involvement of platelets in inflammatory processes like acute ischemic stroke, and viral infections like Coronavirus disease 2019 (COVID-19). This has encouraged the researchers to investigate the contribution of platelets in the pathology of various thrombo-inflammatory diseases. The inhibition of platelet surface receptors or their intracellular signaling which mediate initial platelet activation and adhesion might prove to be suitable targets in thrombo-inflammatory disorders. Thus, the present review summarizes the concept and mechanism of platelet signaling and briefly discuss their role in sterile and non-sterile thrombo-inflammation, with the emphasis on role of platelets in COVID-19 induced thrombo-inflammation. The aim of this review is to summarize the recent developments in deciphering the role of the platelets in thrombo-inflammation and discuss their potential as pharmaceutical targets.

Chronic obstructive pulmonary disease and atherosclerosis: common mechanisms and novel therapeutics

Chronic obstructive pulmonary disease (COPD) and atherosclerosis are chronic irreversible diseases, that share a number of common causative factors including cigarette smoking. Atherosclerosis drastically impairs blood flow and oxygen availability to tissues, leading to life-threatening outcomes including myocardial infarction (MI) and stroke. Patients with COPD are most likely to die as a result of a cardiovascular event, with 30% of all COPD-related deaths being attributed to cardiovascular disease (CVD). Both atherosclerosis and COPD involve significant local (i.e. lung, vasculature) and systemic inflammation and oxidative stress, of which current pharmacological treatments have limited efficacy, hence the urgency for the development of novel life-saving therapeutics. Currently these diseases must be treated individually, with no therapies available that can effectively reduce the likelihood of comorbid CVD other than cessation of cigarette smoking. In this review, the important mechanisms that drive atherosclerosis and CVD in people with COPD are explained and we propose that modulation of both the oxidative stress and the inflammatory burden will provide a novel therapeutic strategy to treat both the pulmonary and systemic manifestations related to these diseases.

Excess Mortality in Aspirin and Dipyrone (Metamizole) Co-Medicated in Patients With Cardiovascular Disease: A Nationwide Study

Background

Pain is a major issue in our aging society. Dipyrone (metamizole) is one of the most frequently used analgesics. Additionally, it has been shown to impair pharmacodynamic response to aspirin as measured by platelet function tests. However, it is not known how this laboratory effect translates to clinical outcome.

Methods and Results

We conducted a nationwide analysis of a health insurance database in Germany comprising 9.2 million patients. All patients with a cardiovascular event in 2014 and subsequent secondary prevention with aspirin were followed up for 36 months. Inverse probability of treatment weighting analysis was conducted to investigate the rate of mortality, myocardial infarction, and stroke/transient ischemic attack between patients on aspirin‐dipyrone co‐medication compared with aspirin‐alone medication. Permanent aspirin‐alone medication was given to 26,200 patients, and 5946 patients received aspirin–dipyrone co‐medication. In the inverse probability of treatment weighted sample, excess mortality in aspirin–dipyrone co‐medicated patients was observed (15.6% in aspirin‐only group versus 24.4% in the co‐medicated group, hazard ratio [HR], 1.66 [95% CI, 1.56–1.76], P<0.0001). Myocardial infarction and stroke/transient ischemic attack were increased as well (myocardial infarction: 1370 [5.2%] versus 355 [5.9%] in aspirin‐only and co‐medicated groups, respectively; HR, 1.18 [95% CI, 1.05–1.32]; P=0.0066, relative risk [RR], 1.14; number needed to harm, 140. Stroke/transient ischemic attack, 1901 [7.3%] versus 506 [8.5%] in aspirin‐only and co‐medicated groups, respectively; HR, 1.22 [95% CI, 1.11–1.35]; P<0.0001, RR, 1.17, number needed to harm, 82).

Conclusions

In this observational, nationwide analysis, aspirin and dipyrone co‐medication was associated with excess mortality. This was in part driven by ischemic events (myocardial infarction and stroke), which occurred more frequently in co‐medicated patients as well. Hence, dipyrone should be used with caution in aspirin‐treated patients for secondary prevention.

Electrical impedance vs. light transmission aggregometry: Testing platelet reactivity to antiplatelet drugs using the MICELI POC impedance aggregometer as compared to a commercial predecessor

BACKGROUND

Patients' responses to antiplatelet therapy significantly vary, with individuals showing high residual platelet reactivity associated with thrombosis. To personalize thrombosis management, platelet function testing has been suggested as a promising tool able to monitor the antithrombotic effect of antiplatelet agents in real-time. We have prototyped the MICELI, a miniature and easy-to-use electrical impedance aggregometer (EIA), measuring platelet aggregation in whole blood. Here, we tested the capability of the MICELI aggregometer to quantify platelet reactivity on antiplatelet agents, as compared with conventional light-transmission aggregometry (LTA).

METHODS

Platelet aggregation in ACD-anticoagulated whole blood and platelet-rich plasma of healthy donors (n = 30) was evaluated. The effect of clopidogrel, ticagrelor, cangrelor, cilostazol, and tirofiban on ADP-induced aggregation was tested, while aspirin was evaluated with arachidonic acid and collagen. Platelet aggregation was recorded using the MICELI or BioData PAP-8E (Bio/Data Corp.) aggregometers.

RESULTS

The MICELI aggregometer detected an adequate and comparable dose-dependent decrease of platelet aggregation in response to increments of drugs' concentrations, as compared to LTA (the inter-device R² = 0.79-0.93). Platelet aggregation in platelet-rich plasma recorded by LTA showed higher sensitivity to antiplatelet agents, but it couldn't distinguish between different drug doses as indicated by saturation of the aggregatory response.

CONCLUSION

Platelet aggregation in whole blood as recorded by EIA represents a better model system for evaluation of platelet reactivity as compared with platelet aggregation in platelet-rich plasma as recorded by LTA, since EIA takes into consideration the modulatory effect of other blood cells on platelet hemostatic function and pharmacodynamics of antiplatelet drugs in vivo. As such, the MICELI impedance aggregometer could be potentially employed for the point-of-care monitoring of platelet function in patients on-treatment for personalized tailoring of their antiplatelet regimen.

The Society for Obstetric Anesthesia and Perinatology Interdisciplinary Consensus Statement on Neuraxial Procedures in Obstetric Patients With Thrombocytopenia

Because up to 12% of obstetric patients meet criteria for the diagnosis of thrombocytopenia in pregnancy, it is not infrequent that the anesthesiologist must decide whether to proceed with a neuraxial procedure in an affected patient. Given the potential morbidity associated with general anesthesia for cesarean delivery, thoughtful consideration of which patients with thrombocytopenia are likely to have an increased risk of spinal epidural hematoma with neuraxial procedures, and when these risks outweigh the relative benefits is important to consider and to inform shared decision making with patients. Because there are substantial risks associated with withholding a neuraxial analgesic/anesthetic procedure in obstetric patients, every effort should be made to perform a bleeding history assessment and determine the thrombocytopenia etiology before admission for delivery. Whereas multiple other professional societies (obstetric, interventional pain, and hematologic) have published guidelines addressing platelet thresholds for safe neuraxial procedures, the US anesthesia professional societies have been silent on this topic. Despite a paucity of high-quality data, there are now meta-analyses that provide better estimations of risks. An interdisciplinary taskforce was convened to unite the relevant professional societies, synthesize the data, and provide a practical decision algorithm to help inform risk-benefit discussions and shared decision making with patients. Through a systematic review and modified Delphi process, the taskforce concluded that the best available evidence indicates the risk of spinal epidural hematoma associated with a platelet count ≥70,000 × 106/L is likely to be very low in obstetric patients with thrombocytopenia secondary to gestational thrombocytopenia, immune thrombocytopenia (ITP), and hypertensive disorders of pregnancy in the absence of other risk factors. Ultimately, the decision of whether to proceed with a neuraxial procedure in an obstetric patient with thrombocytopenia occurs within a clinical context. Potentially relevant factors include, but are not limited to, patient comorbidities, obstetric risk factors, airway examination, available airway equipment, risk of general anesthesia, and patient preference.

Pleiotropic Effects of Acetylsalicylic Acid after Coronary Artery Bypass Grafting-Beyond Platelet Inhibition

Acetylsalicylic acid (ASA) is one of the most frequently used medications worldwide. Yet, the main indications for ASA are the atherosclerosis-based cardiovascular diseases, including coronary artery disease (CAD). Despite the increasing number of percutaneous procedures to treat CAD, coronary artery bypass grafting (CABG) remains the treatment of choice in patients with multivessel CAD and intermediate or high anatomical lesion complexity. Taking into account that CABG is a potent activator of inflammation, ASA is an important part in the postoperative therapy, not only due to ASA antiplatelet action, but also as an anti-inflammatory agent. Additional benefits of ASA after CABG include anticancerogenic, hypotensive, antiproliferative, anti-osteoporotic, and neuroprotective effects, which are especially important in patients after CABG, prone to hypertension, graft occlusion, atherosclerosis progression, and cognitive impairment. Here, we discuss the pleiotropic effects of ASA after CABG and provide insights into the mechanisms underlying the benefits of treatment with ASA, beyond platelet inhibition. Since some of ASA pleiotropic effects seem to increase the risk of bleeding, it could be considered a starting point to investigate whether the increase of the intensity of the treatment with ASA after CABG is beneficial for the CABG group of patients.

Cranberry supplementation as a cause of major intraoperative bleeding during vascular surgery due to aspirin-like platelet inhibition

We report severe excessive bleeding at initiation of vascular surgery in a 74-year-old woman with thoracoabdominal aortic aneurysm undergoing thoracic endovascular aortic repair. After extensive workup, bleeding cause was determined to be an aspirin-like effect from supplemental cranberry intake. After asking the patient to stop cranberry consumption, the aspirin-like effect ceased, and the patient underwent successful thoracic endovascular aortic repair. Cranberry consumption may create an aspirin-like effect that increases risk of bleeding. Providers should be aware of potential adverse effects of cranberries on platelet function and consider inquiring about supplement use in the perioperative period.

Can Endothelial Glycocalyx Be a Major Morphological Substrate in Pre-Eclampsia?

Today pre-eclampsia (PE) is considered as a disease of various theories; still all of them agree that endothelial dysfunction is the leading pathogenic factor. Endothelial dysfunction is a sequence of permanent immune activation, resulting in the change of both the phenotype and the functions of an endothelial cell and of the extracellular layer associated with the cell membrane—endothelial glycocalyx (eGC). Numerous studies demonstrate that eGC mediates and regulates the key functions of endothelial cells including regulation of vascular tone and thromboresistance; and these functions are disrupted during PE. Taking into account that eGC and its components undergo alterations under pathological conditions leading to endothelial activation, it is supposed that eGC plays a certain role in pathogenesis of PE. Envisaging the eGC damage as a key factor of PE, might be a new approach to prevention, treatment, and rehabilitation of patients with PE. This approach could include the development of drugs protecting eGC and promoting regeneration of this structure. Since the issue of PE is far from being solved, any effort in this direction might be valuable.

Aspirin-loaded nanoexosomes as cancer therapeutics

The long history of discovery and recently encouraging studies of the anti-cancer effect of aspirin promise a closer step to widely used aspirin-based medication in cancer therapy. To resolve the poor water-solubility of aspirin and low encapsulation efficiency of exosomes for further developing a new delivery of aspirin as anti-cancer treatment, our nanoamorphous exosomal delivery platform was established. In this study, the anti-tumour effects of nanoamorphous aspirin-loaded exosomes with exosomes derived from breast and colorectal cancer cells, were comprehensively studied using both in vitro and in vivo models. These exosomes displayed enhanced cellular uptake via both clathrin-dependent and -independent endocytosis pathways, and significantly improved cytotoxicity of aspirin to breast and colorectal cancer cells, accompanied by the enhanced apoptosis and autophagy. Remarkably, this nanoamorphous exosomal platform endowed aspirin with the unprecedented cancer stem cell eradication capacity. Further animal study demonstrated that this developed exosomal system was able to efficiently deliver aspirin to in vivo tumours. The active targeting of these exosomes to tumour was further improved by conjugating an aptamer specifically targeting EpCAM protein. Hence, this nanoamorphous structured exosome system effectively transformed aspirin into a potential cancer stem cell killer with distinguished properties for clinical translation.

Association between preoperative aspirin and acute kidney injury following coronary artery bypass grafting

OBJECTIVE

To test the hypothesis that preoperative aspirin administered within 24 hours before coronary artery bypass grafting (CABG) could reduce the incidence of postoperative acute kidney injury (AKI) following CABG.

METHODS

In this retrospective study, 696 patients were assigned to groups according to the time interval between their last aspirin dose administration and the time of surgery. A total of 322 patients received aspirin ≤24 hours before CABG, and 374 patients received aspirin between 24 and 48 hours before CABG. The primary outcome was postoperative AKI of any stage as defined by the Kidney Disease Improving Global Outcomes criteria. Propensity score matching selected 274 pairs for the final comparison.

RESULTS

Multivariable analysis showed that administration of aspirin within 24 hours of CABG was independently associated with reduction of AKI incidence by 36% (odds ratio, 0.64; 95% confidence interval, 0.45-0.91; P = .014). It was also noted that patients receiving their last aspirin dose ≤24 hours before CABG had a significantly higher glomerular filtration rate at discharge compared with patients who received aspirin between 24 and 48 hours before CABG. Propensity score matching analysis showed that patients receiving aspirin within 24 hours before CABG had a lower incidence of AKI compared with patients who discontinued aspirin between 24 and 48 hours before CABG (25.1% vs 36.8%; P = .004).

CONCLUSIONS

Continuation of aspirin until the day of surgery, with the last aspirin dose administered ≤24 hours before CABG, is associated with a significant reduction of postoperative AKI.

Platelet Signaling and Disease: Targeted Therapy for Thrombosis and Other Related Diseases

Platelets are essential for clotting in the blood and maintenance of normal hemostasis. Under pathologic conditions such as atherosclerosis, vascular injury often results in hyperactive platelet activation, resulting in occlusive thrombus formation, myocardial infarction, and stroke. Recent work in the field has elucidated a number of platelet functions unique from that of maintaining hemostasis, including regulation of tumor growth and metastasis, inflammation, infection, and immune response. Traditional therapeutic targets for inhibiting platelet activation have primarily been limited to cyclooxygenase-1, integrin αIIbβ3, and the P2Y12 receptor. Recently identified signaling pathways regulating platelet function have made it possible to develop novel approaches for pharmacological intervention in the blood to limit platelet reactivity. In this review, we cover the newly discovered roles for platelets as well as their role in hemostasis and thrombosis. These new roles for platelets lend importance to the development of new therapies targeted to the platelet. Additionally, we highlight the promising receptor and enzymatic targets that may further decrease platelet activation and help to address the myriad of pathologic conditions now known to involve platelets without significant effects on hemostasis.

Inhibition of high shear arterial thrombosis by charged nanoparticles

Platelet accumulation under high shear rates at the site of atherosclerotic plaque rupture leads to myocardial infarction and stroke. Current antiplatelet therapies remain ineffective within a large percentage of the population, while presenting significant risks for bleeding. We explore a novel way to inhibit arterial thrombus formation by biophysical means without the use of platelet inactivating drugs. Our computational multi-scale dynamics model has predicted that charged particles of a specific size may entangle von Willebrand Factor (vWF) polymers and reduce the amount of elongation at high shear rates. We tested this hypothesis experimentally for negatively charged nanoparticles (CNP) to inhibit arterial thrombus formation. CNP of a particular size and charge inhibited thrombus formation, with a 10-fold peak inhibition over control conditions of thrombotic occlusion. Particles of differing material composition, size, and charge had little effect as predicted by computational studies. Surprisingly, the dose response curve was not sigmoidal, but exhibited a peak at 1.5 CNP:vWF proteins, which was not predicted by the model. This study describes a new antithrombotic agent that may have a different mechanism of action than current pharmaceutical therapies.

Antipyretic therapy: clinical pharmacology

Fever depends on a complex physiologic response to infectious agents and other conditions. To alleviate fever, many medicinal agents have been developed over a century of trying to improve upon aspirin, which was determined to work by inhibiting prostaglandin synthesis. We present the process of fever induction through prostaglandin synthesis and discuss the development of pharmaceuticals that target enzymes and receptors involved in prostaglandin-mediated signal transduction, including prostaglandin H₂ synthase (also known as cyclooxygenase), phospholipase A₂, microsomal prostaglandin E₂ synthase-1, EP receptors, and transient potential cation channel subfamily V member 1. Clinical use of established antipyretics will be discussed as well as medicinal agents under clinical trials and future research.

Point-of-Care-Testing in Acute Stroke Management: An Unmet Need Ripe for Technological Harvest

Stroke, the second highest leading cause of death, is caused by an abrupt interruption of blood to the brain. Supply of blood needs to be promptly restored to salvage brain tissues from irreversible neuronal death. Existing assessment of stroke patients is based largely on detailed clinical evaluation that is complemented by neuroimaging methods. However, emerging data point to the potential use of blood-derived biomarkers in aiding clinical decision-making especially in the diagnosis of ischemic stroke, triaging patients for acute reperfusion therapies, and in informing stroke mechanisms and prognosis. The demand for newer techniques to deliver individualized information on-site for incorporation into a time-sensitive work-flow has become greater. In this review, we examine the roles of a portable and easy to use point-of-care-test (POCT) in shortening the time-to-treatment, classifying stroke subtypes and improving patient's outcome. We first examine the conventional stroke management workflow, then highlight situations where a bedside biomarker assessment might aid clinical decision-making. A novel stroke POCT approach is presented, which combines the use of quantitative and multiplex POCT platforms for the detection of specific stroke biomarkers, as well as data-mining tools to drive analytical processes. Further work is needed in the development of POCTs to fulfill an unmet need in acute stroke management.

Antiplatelet and Anticoagulant Therapies for Prevention of Ischemic Stroke

Ischemic stroke represents one of the leading causes of death and disability in both the United States and abroad, particularly for patients with prior ischemic stroke or transient ischemic attack (TIA). A quintessential aspect of secondary stroke prevention is the use of different pharmacological agents, mainly antiplatelets and anticoagulants. Antiplatelets and anticoagulants exhibit their effect by blocking the activation pathways of platelets and the coagulation cascade, respectively. Clinical trials have demonstrated the safety and efficacy of antiplatelets for noncardioembolic stroke prevention, while anticoagulants are more often used for cardioembolic stroke prevention. Commonly used antiplatelets include aspirin, clopidogrel, and aggrenox (aspirin plus extended-release dipyridamole). Furthermore, commonly used anticoagulants include warfarin, dabigatran, rivaroxaban, apixaban, and edoxaban. Each of these drugs has a unique mechanism of action, and they share some common adverse events such as gastrointestinal bleeding and intracranial hemorrhage in more serious cases. Consequently, physicians should carefully assess the benefits and risks of using different antiplatelet or anticoagulant therapies when managing patients with previous ischemic stroke or TIA. This review discuses the published literature on major clinical trials assessing the efficacy of different antiplatelet and anticoagulant drugs under varying circumstances and the subsequent guidelines that have been developed by the American Heart Association/American Stroke Association. Additionally, the role of imaging in stroke prevention is discussed.

Clopidogrel Resistance: Myth or Reality?

Platelets have a central role in the development of arterial thrombosis and subsequent cardiovascular events. An appreciation of this complex process has made antiplatelet therapy the cornerstone of cardiovascular disease management. Dual antiplatelet therapy with aspirin and clopidogrel has been approved for the secondary prevention of cardiovascular events and is currently part of the postpercutaneous coronary intervention treatment regimen. However, subacute stent thrombosis continues to occur in 1% to 2% of patients despite dual antiplatelet therapy. Studies have shown interindividual variations in response to clopidogrel, where a cohort of patients seems to be resistant to the antithrombotic effects of clopidogrel. Furthermore, there is an apparent link between clopidogrel resistance and clinical outcomes. Currently, there is neither a universally accepted definition of clopidogrel resistance nor an agreement on the phenomenon's mechanism. This review highlights the origins of clopidogrel resistance, the current problems that exist with its definition, and discusses the future implications and relevant challenges it poses for the clinician.

Platelets: still a therapeutical target for haemostatic disorders

Platelets are cytoplasmatic fragments from bone marrow megakaryocytes present in blood. In this work, we review the basis of platelet mechanisms, their participation in syndromes and in arterial thrombosis, and their potential as a target for designing new antithrombotic agents. The option of new biotechnological sources is also explored.

Platelet function testing: state of the art

Platelet function testing has evolved from crude tests, such as the bleeding time, to tests that permit a relatively sophisticated evaluation of platelet activity. Nonetheless, these tests are hampered by lack of specificity and sensitivity, and poor standardization of methods and techniques. The bleeding time, which has long been a staple of hemostasis testing, has been dropped from the test menu at many laboratories. In its place, tests such as the Platelet Function Analyzer-100 are increasingly used to screen patients with possible bleeding disorders. Older tests, such as platelet aggregometry and lumiaggregometry, are still used frequently because they provide insight into receptor, signaling pathway and granule release mechanisms. Flow cytometry is available in some specialized laboratories and allows for quantitative and qualitative assessment of some platelet functions, although the expense of testing is often prohibitive. Finally, the wider availability of platelet function testing has stimulated interest and demand for monitoring the effect of platelet inhibitory drugs, such as aspirin and clopidogrel. As platelet function pathways become better understood, the demand for these type of monitoring tests is likely to increase.

Safety and Efficacy Outcomes of Preoperative Aspirin in Patients Undergoing Coronary Artery Bypass Grafting

Background:

The administration of aspirin is traditionally discontinued prior to coronary artery bypass grafting (CABG), given a potential risk of excessive postoperative bleeding. Few studies have previously suggested the benefits of continuing aspirin until the time of surgery. The primary aim of this review is to evaluate the effects of preoperative aspirin therapy on several clinically important outcomes in patients undergoing CABG.

Methods:

A meta-analysis of eligible studies of patients undergoing CABG, reporting preoperative aspirin in comparison with no aspirin/placebo and our outcomes, was carried out. The safety outcomes included postoperative bleeding, packed red blood cell (PRBC) transfusion requirements, and reoperation for bleeding. The efficacy outcomes included perioperative myocardial infarction (MI), cerebrovascular accidents (CVAs), and mortality.

Results:

In 8 randomized controlled trials (RCTs; n = 1538), preoperative aspirin increased postoperative bleeding (difference in means = 132.30 mL; 95 % confidence interval [CI] 47.10-217.51; P = .002), PRBC transfusion requirements (difference in means = 0.67 units; 95% CI 0.10-1.24; P = .02), and reoperation for bleeding (odds ratio [OR] = 1.76; 95% CI 1.05-2.93; P = .03). In 19 observational studies (n = 19551), preoperative aspirin increased postoperative bleeding (difference in means = 132.74 mL; 95% CI 45.77-219.72; P = .003) and PRBC transfusion requirements (difference in means = 0.19 units; 95% CI 0.02-0.35; P = .02) but not reoperation for bleeding (OR = 1.13; 95% CI 0.91-1.42; P = .27). Subgroup analyses for RCTs demonstrated that aspirin given at doses ≤ 100 mg/d might not increase the postoperative bleeding, and the dose of 325 mg/d might not be a cutoff value that has clinical and statistical significance. No statistically significant differences in the rate of perioperative MI, CVAs, or mortality were seen between the 2 groups.

Conclusions:

Preoperative aspirin therapy is associated with increased postoperative bleeding, PRBC transfusion requirements, and reoperation for bleeding in patients undergoing CABG. Doses lower than 100 mg/d may minimize the risk of bleeding. Additional RCTs are needed to assess the effects of preoperative aspirin on the safety and efficacy outcomes in patients undergoing CABG.

Hypertension as a Risk Factor for Aspirin and Clopidogrel Resistance in Patients With Stable Coronary Artery Disease

Background:

Platelets play an important role in the pathogenesis of coronary artery disease (CAD). The importance of dual antiplatelet therapy to prevent recurrent ischemic events in patients who have acute coronary syndrome and who will undergo percutaneous coronary intervention (PCI) is well known and widely accepted as a gold standard. However, despite this apparently effective therapy, incidence of adverse ischemic events could not be decreased enough. Resistance to aspirin/clopidogrel is an important risk factor for adverse ischemic clinical events. Up-to-date studies revealed many risk factors for antiplatelet resistance, one of which is hypertension (HT). Currently, there is no sufficient number of studies evaluating the association between HT and antiplatelet resistance, which is the aim of this study.

Methods:

We enrolled 145 consecutive patients (19 female [13.1%], 126 male [86.9%], mean age 55 ± 10) with stable CAD receiving regular antiplatelet therapy composed of 100 mg/d aspirin and 75 mg/d clopidogrel. All patients had been implanted nondrug-eluting coronary stent and/or stents at least 1 month ago. The HT was diagnosed by 24-hour blood pressure (BP) monitoring. Clopidogrel and aspirin resistance was measured by impedance aggregometry method.

Results:

We included 49 patients with HT and 96 nonhypertensive patients with stable CAD. Aspirin resistance was detected in 22 (16.4%) of 134 patients who received aspirin. Clopidogrel resistance was detected in 55 (37.9%) of 145 patients who received clopidogrel. Prevalance of aspirin and clopidogrel resistance was significantly higher in the hypertensive group than in the nonhypertensive group ( P = .030 and P = .007, respectively). Correlation analysis revealed weak but significantly positive correlation between clopidogrel resistance and serum uric acid levels, mean platelet volume, platelet count, and 24-hour mean systolic BP ( r = −.180, P = .030; r = .189, P = .016; r = .226, P = .006; and r = .200, P = .016, respectively).

Conclusion:

We demonstrated higher incidence of antiplatelet resistance in patients with HT. Upon this finding, which is emerged from an actual group of patients with HT, cardioprotective effect of antiplatelet therapy in patients with HT should be argued.

Antiplatelet therapy: aspirin resistance and all that jazz!

Platelets play a crucial role in the pathogenesis of atherosclerosis, thrombosis, and stroke. Aspirin used alone or in combination with other antiplatelet drugs has been shown to offer significant benefit to patients at high risk of vascular events. Resistance to the action of aspirin may decrease this benefit. Aspirin resistance has been defined by clinical and/or laboratory criteria; however, detection by laboratory methods prior to experiencing a clinical event will likely provide the greatest opportunity for intervention. Numerous laboratory methods with different cutoff points have been used to evaluate the resistance. Noncompliance with aspirin treatment has also confounded studies. A single assay is currently insufficient to establish resistance. Combinations of results to confirm compliance and platelet inhibition may identify "at-risk" individuals who truly have aspirin resistance. The most effective strategy for managing patients with aspirin resistance is unknown; however, studies are currently underway to address this issue.

Aspirin prophylaxis for the prevention of thrombosis: expectations and limitations

Platelets play a very important role in the pathogenesis of acute vascular events leading to thrombosis of the coronary and cerebral arteries. Blockage of these arteries leading to regional ischemia of heart and brain tissues precipitate heart attacks and stroke. Acetyl salicylic acid (Aspirin) has been the drug of choice for over half a century for the primary and secondary prophylaxis of thrombotic events. In spite of its extensive use as an antiplatelet drug for the prevention of vascular thrombosis, there is considerable concern about the degree of protection it offers, to patients under aspirin therapy. In this paper, we explain the phenomenon of aspirin resistance, discuss the limitations of aspirin therapy, and suggest methods to monitor "at-risk" individuals. Ability to monitor and determine at risk patients will provide opportunities for the clinicians to customize antiplatelet therapies.

Thromboembolic events during the perioperative period in patients undergoing permanent pacemaker implantation

BACKGROUND

Thromboembolism (TE) is one of the most serious complications after pacemaker implantation. It has been demonstrated that several patient characteristics and different pacing modes are related to an increased risk of TE events during long-term follow-up.

HYPOTHESIS

We propose that TE events occurring during the perioperative period of pacemaker implantation may be associated with certain clinical characteristics.

METHODS

The potential risk factors of TE events were analyzed in 406 consecutive patients who underwent pacemaker implantation.

RESULTS

We identified TE events in 11 patients (2.7%) within 7 days after pacemaker implantation. Four of the 11 (36.4%) patients died of complications of TE. Univariate analysis revealed that an age of >75 years (4.56 odds ratio [OR], P = 0.031), hypertension (3.59 OR, P = 0.028), diabetes (8.89 OR, P < 0.001), coronary heart disease (4.8 OR, P = 0.005), atrial fibrillation (AF) (5.68 OR, P = 0.006), persistent AF (10.36 OR, P < 0.001), and a history of stroke or transient ischemic attack (5.62 OR, P = 0.002) were associated with an increased risk of TE events. Multivariate logistic analysis showed that persistent AF (9.8 OR, P < 0.001) was independently associated with TE. The incidence of perioperative TE was not significantly different between patients with single- and dual-chamber pacemakers.

CONCLUSIONS

We found TE events during the perioperative period in patients undergoing pacemaker implantation were not uncommon. Because persistent AF during the perioperative period was the only independent risk factor for perioperative TE, appropriate anticoagulation therapy may be necessary in those patients. © 2012 Wiley Periodicals, Inc. J. Liu, MD, is co-first author. The authors have no funding, financial relationships, or conflicts of interest to disclose.

Bleeding tendency in dual antiplatelet therapy with aspirin/clopidogrel: rescue of the template bleeding time in a single-center prospective study

Background

Patients with heightened platelet reactivity in response to antiplatelet agents are at an increased risk of recurrent ischemic events. However, there is a lack of diagnostic criteria for increased response to combined aspirin/clopidogrel therapy. The challenge is to identify patients at risk of bleeding. This study sought to characterize bleeding tendency in patients treated with aspirin and clopidogrel.

Patients/methods

In a single-center prospective study, 100 patients under long-term aspirin/clopidogrel treatment, the effect of therapy was assayed by template bleeding time (BT) and the inhibition of platelet aggregation (IPA) by light transmission aggregometry (LTA). Arachidonic acid (0.625 mmol/L) and adenosine diphosphate (ADP; 2, 4, and 8 μmol/L) were used as platelet agonists.

Results

Bleeding episodes (28 nuisance, 2 hematuria [1 severe], 1 severe proctorrhagia, 1 severe epistaxis) were significantly more frequent in patients with longer BT. Template BT ≥ 24 min was associated with bleeding episodes (28 of 32). Risk of bleeding increased 17.4% for each 1 min increase in BT. Correlation was found between BT and IPAmax in response to ADP 2 μmol/L but not to ADP 4 or 8 μmol/L.

Conclusion

In patients treated with dual aspirin/clopidogrel therapy, nuisance and internal bleeding were significantly associated with template BT and with IPAmax in response to ADP 2 μmol/L but not in response to ADP 4 μmol/L or 8 μmol/L.

Good short-term but not long-term reproducibility of the antiplatelet efficacy laboratory assessment

BACKGROUND

The antiplatelet effect of acetylsalicylic acid (ASA) varies among individual patients. We assessed the short-term reproducibility (STR) and long-term reproducibility (LTR) of light transmission aggregometry (LTA).

METHODS

Residual platelet reactivity was measured twice using LTA in a group of 207 consecutive patients (56 females, mean age 67 ± 9 years) on ASA therapy in 10 ± 6 months interval. The STR was assessed in 15 patients (6 females, mean age 61 ± 7 years) with 10 measurements on 2 consecutive days.

RESULTS

There was no correlation between both measurements in the long-term part of the study, and also Bland-Altman plot showed a diverging pattern. However, LTA STR was good with a correlation coefficient of .800 (P < .05) confirmed by Bland-Altman plot.

CONCLUSIONS

Although short-term intraindividual reproducibility of LTA assessment of platelet reactivity is very good, in the long-term perspective the antiplatelet ASA effectivity may be influenced by additional variables and repeated measurements are warranted.

Battle of oral anticoagulants in the field of atrial fibrillation scrutinized from a clinical practice (the real world) perspective

Warfarin has a long history of benefit and has become the gold standard medication for the prevention of ischemic stroke in patients with atrial fibrillation. Nevertheless, it is far from perfect and there is no doubt that new drugs must be found to replace warfarin. The new oral anticoagulants that are on the market or awaiting approval or under research offer some benefits but not enough to replace warfarin until results of additional studies can show an adequate balance between effectiveness/safety and cost/benefit. There are several issues concerning the new oral anticoagulants. It is essential that the effect of any anticoagulant can be measured in plasma. But to date, there is no test to assess the effect or therapeutic range for the new oral anticoagulants. There is no antidote to neutralize the action of the new drugs in cases of bleeding or when acute surgical intervention is necessary. Dabigatran requires dose adjustment in patients with moderate renal impairment and is contraindicated in patients with severe renal failure. Rivaroxaban should be used with caution in patients with severe renal impairment. Apixaban excretion is also partly dependent on renal function, although the impact of renal insufficiency has not yet been determined. How anticoagulant bridging can be done before surgery has not yet been established. In conclusion, although thousands of patients have been treated in phase III studies, additional data are necessary before conclusions can be drawn on the potential for these new anticoagulant drugs to replace warfarin in patients with atrial fibrillation.

What every emergency nurse needs to know about aspirin: an update

In 2005, we presented a manuscript about the use of aspirin (ASA) in the setting of the Emergency Department (ED). We now write to report recent developments in our understanding about ASA and individual responses to the medication. The phenomenon of aspirin resistance is explored.