New antiplatelet drugs and new oral anticoagulants

Low-Dose Aspirin during Pregnancy and Postpartum Bleeding

OBJECTIVE

This study aimed to investigate whether aspirin 81 mg daily for preeclampsia prevention is associated with increased risk of postpartum blood loss at the time of delivery.

STUDY DESIGN

This is a retrospective cohort study performed at a tertiary hospital from January 2018 to April 2021. Data were extracted from the electronic medical record. Patients prescribed low-dose aspirin (LDA) were compared with patients who were not. The primary outcome was a composite of postpartum blood loss, defined as: estimated blood loss (EBL) >1,000 mL, documentation of International Classification of Diseases-9/-10 codes for postpartum hemorrhage (PPH), or red blood cell (RBC) transfusion. Bivariate analysis, and unadjusted and adjusted logistic regression modeling were performed.

RESULTS

Among 16,980 deliveries, 1,922 (11.3%) were prescribed LDA. Patients prescribed LDA were more likely to be >35 years old, nulliparous, obese, taking other anticoagulants, or have diagnoses of diabetes, systemic lupus erythematosus, fibroids, or hypertensive disease of pregnancy. After adjusting for potential confounders, the significant association between LDA use and the composite did not persist (adjusted odds ratio [aOR]: 1.1, 95% confidence interval [CI]: 1.0-1.3) nor did the association between EBL > 1,000 mL (aOR: 1.0, 95% CI: 0.9-1.3) and RBC transfusion (aOR: 1.3, 95% CI: 0.9-1.7). The association between LDA and PPH remained significant (aOR: 1.3, 95% CI: 1.1-1.6). Patients who discontinued LDA <7 days prior to delivery had an increased risk of the postpartum blood loss composite compared discontinuation ≥7 days (15.0 vs. 9.3%; p = 0.03).

CONCLUSION

There may be an association between LDA use and increased risk of postpartum bleeding. This suggests that use of LDA outside the recommended guidelines should be cautioned and further investigation is needed to determine its ideal dosing and timing of discontinuation.

KEY POINTS

· There may be an association with LDA and an increased risk of postpartum bleeding.. · Patients who discontinued LDA less than 7 days prior to delivery had an increased rate of postpartum bleeding.. · Additional research is need to determine optimal LDA dose and timing of discontinuation..

Endothelial dysfunction, platelet hyperactivity, hypertension, and the metabolic syndrome: molecular insights and combating strategies

Metabolic syndrome (MetS) is a multifaceted condition that increases the possibility of developing atherosclerotic cardiovascular disease. MetS includes obesity, hypertension, dyslipidemia, hyperglycemia, endothelial dysfunction, and platelet hyperactivity. There is a concerning rise in the occurrence and frequency of MetS globally. The rising incidence and severity of MetS need a proactive, multipronged strategy for identifying and treating those affected. For many MetS patients, achieving recommended goals for healthy fat intake, blood pressure control, and blood glucose management may require a combination of medicine therapy, lifestyles, nutraceuticals, and others. However, it is essential to note that lifestyle modification should be the first-line therapy for MetS. In addition, MetS requires pharmacological, nutraceutical, or other interventions. This review aimed to bring together the etiology, molecular mechanisms, and dietary strategies to combat hypertension, endothelial dysfunction, and platelet dysfunction in individuals with MetS.

Mechanoresponsive Drug Delivery Systems for Vascular Diseases

Mechanoresponsive drug delivery systems (DDS) have emerged as promising candidates to improve the current effectiveness and lower the side effects typically associated with direct drug administration in the context of vascular diseases. Despite tremendous research efforts to date, designing drug delivery systems able to respond to mechanical stimuli to potentially treat these diseases is still in its infancy. By understanding relevant biological forces emerging in healthy and pathological vascular endothelium, it is believed that better-informed design strategies can be deduced for the fabrication of simple-to-complex macromolecular assemblies capable of sensing mechanical forces. These responsive systems are discussed through insights into essential parameter design (composition, size, shape, and aggregation state) , as well as their functionalization with (macro)molecules that are intrinsically mechanoresponsive (e.g., mechanosensitive ion channels and mechanophores). Mechanical forces, including the pathological shear stress and exogenous stimuli (e.g., ultrasound, magnetic fields), used for the activation of mechanoresponsive DDS are also introduced, followed by in vitro and in vivo experimental models used to investigate and validate such novel therapies. Overall, this review aims to propose a fresh perspective through identified challenges and proposed solutions that could be of benefit for the further development of this exciting field.

In vitro and in vivo implications of rationally designed bromelain laden core-shell hybrid solid lipid nanoparticles for oral administration in thrombosis management

Bromelain, a dietary supplement of cysteine protease family having promising results against thrombosis, is gaining attention. Yet poor mechanical stability, gastric instability, high oral dose and poor patient compliance restricted its clinical application. Therefore, acid stable bromelain loaded hybrid solid lipid nanoparticles (Br-HNPs) were fabricated and characterized for their contribution to in-vivo stability and therapeutic efficacy in thrombosis management. Comprehensive optimization of various process and formulation variables ensued the formation of nano-sized (120.56 ± 40.12 nm) Br-HNPs with entrapment efficiency of 86.32 ± 5.56%. Spherical core shell framework of Br-HNPs prolonged drug release and provided in-vivo and storage stability at room temperature. Br-HNPs significantly inhibited platelet aggregation without affecting bleeding time and dissolved thrombus at 1.91-fold higher efficacy compared to bromelain. Furthermore, Br-HNPs prevented hypercoagulation states and suppressed cytokines production significantly (P < .05) contributing to its antiplatelet activity. These findings indicated that Br-HNPs could serve as a promising alternative to commercial therapies for management of thrombotic disorders.

Efficacy and safety of a bridging strategy that uses intravenous platelet glycoprotein receptor inhibitors for patients undergoing surgery after coronary stent implantation: a meta-analysis

BACKGROUND

Current guidelines indicate we can consider a bridging strategy that uses intravenous, reversible glycoprotein inhibitors for patients that required surgery following recent stent implantation. However, no strong clinical evidence exists that demonstrates the efficacy and safety of this treatment. Therefore, in this study, the efficacy and safety of a bridging strategy that uses intravenous platelet glycoprotein receptor inhibitors will be evaluated.

METHODS

A meta-analysis was performed on preoperative bridging studies in patients undergoing coronary stent surgery. The primary outcome was the success rate of no major adverse cardiovascular events (MACE). The secondary outcomes were the success rate of no reoperations to stop bleeding.

RESULTS

A total of 10 studies that included 382 patients were used in this meta-analysis. For the primary endpoint, the success rate was 97.7% (95% CI 94.4-98.0%) for glycoprotein IIb/IIIa inhibitors, 98.8% (95% CI 96.0-100%) for tirofiban (6 studies) and 95.8% (95% CI 90.4-99.4%) for eptifibatide (4 studies). For secondary endpoints, the success rate was 98.0% (95% CI 94.8-99.9%) for glycoprotein IIb/IIIa inhibitors, 99.7% (95% CI 97.1-100%) for tirofiban (5 studies), and 95.3% (95% CI 88.5-99.4%) for eptifibatide (4 studies).

CONCLUSION

The results of this study showed that the use of intravenous platelet glycoprotein IIb/IIIa inhibitors as a bridging strategy might be safe and effective for patients undergoing coronary stent implantation that require surgery soon after.

Narrative Review of Antiplatelet and Anticoagulant Medications for Venous Thromboembolism Prevention in Spine Surgery

STUDY DESIGN

This was a narrative review.

OBJECTIVE

The objective of this study was to identify commonly utilized venous thromboembolism (VTE) prophylactic measures, spine surgeon perspective, and provide pharmacologic recommendations from the literature.

SUMMARY OF BACKGROUND DATA

Considered a preventable cause of morbidity and mortality, VTE remains an important iatrogenic diagnosis of concern. Reported rates of VTE following spine surgery vary widely (0.3%-31.0%).

MATERIALS AND METHODS

A MEDLINE query identified literature reporting on VTE prevention and outcomes in the setting of spine surgery. Findings extracted from the included articles were summarized in a narrative review format to identify salient aspects of the current literature.

RESULTS

Sixty articles were summarized. Many anticoagulation medications that are described in the literature target factors involved in the coagulation cascade common pathway including aspirin and other antiplatelet medications, heparins, and warfarin. Newer direct inhibitors of thrombin and factor Xa are now being utilized for VTE prevention, although with limited use specifically in spine surgery.

CONCLUSIONS

Perioperative management of antiplatelet and anticoagulation medications in spine surgery requires evidence-based protocols that can account for patient comorbidities and surgery-specific features. Future studies should prospectively focus on establishing stronger recommendations based on pathology, surgical indications, patient comorbidities, region of the spine, and broad surgical intervention to enable effective prophylaxis for VTE.

LEVEL OF EVIDENCE

Level II.

Platelet Mechanobiology Inspired Microdevices: From Hematological Function Tests to Disease and Drug Screening

Platelet function tests are essential to profile platelet dysfunction and dysregulation in hemostasis and thrombosis. Clinically they provide critical guidance to the patient management and therapeutic evaluation. Recently, the biomechanical effects induced by hemodynamic and contractile forces on platelet functions attracted increasing attention. Unfortunately, the existing platelet function tests on the market do not sufficiently incorporate the topical platelet mechanobiology at play. Besides, they are often expensive and bulky systems that require large sample volumes and long processing time. To this end, numerous novel microfluidic technologies emerge to mimic vascular anatomies, incorporate hemodynamic parameters and recapitulate platelet mechanobiology. These miniaturized and cost-efficient microfluidic devices shed light on high-throughput, rapid and scalable platelet function testing, hematological disorder profiling and antiplatelet drug screening. Moreover, the existing antiplatelet drugs often have suboptimal efficacy while incurring several adverse bleeding side effects on certain individuals. Encouraged by a few microfluidic systems that are successfully commercialized and applied to clinical practices, the microfluidics that incorporate platelet mechanobiology hold great potential as handy, efficient, and inexpensive point-of-care tools for patient monitoring and therapeutic evaluation. Hereby, we first summarize the conventional and commercially available platelet function tests. Then we highlight the recent advances of platelet mechanobiology inspired microfluidic technologies. Last but not least, we discuss their future potential of microfluidics as point-of-care tools for platelet function test and antiplatelet drug screening.

[SBA 2020: Regional anesthesia guideline for using anticoagulants update]

The development of protocols to prevent perioperative Venous Thromboembolism (VTE) and the introduction of increasingly potent antithrombotic drugs have resulted in concerns of increased risk of neuraxial bleeding. Since the Brazilian Society of Anesthesiology (SBA) 2014 guideline, new oral anticoagulant drugs were approved by international regulating agencies, and by ANVISA. Societies and organizations that try to approach concerns through guidelines have presented conflicting perioperative management recommendations. As a response to these issues and to the need for a more rational approach, managements were updated in the present narrative revision, and guideline statements made. They were projected to encourage safe and quality patient care, but cannot assure specific results. Like any clinical guide recommendation, they are subject to review as knowledge grows, on specific complications, for example. The objective was to assess safety aspects of regional analgesia and anesthesia in patients using antithrombotic drugs, such as: possible technique-associated complications; spinal hematoma-associated risk factors, prevention strategies, diagnosis and treatment; safe interval for discontinuing and reinitiating medication after regional blockade.

Platelet activation and prothrombotic mediators at the nexus of inflammation and atherosclerosis: Potential role of antiplatelet agents

Platelets are central to inflammation-related manifestations of cardiovascular diseases (CVD) such as atherosclerosis. Platelet-activating factor (PAF), thrombin, thromboxane A₂ (TxA₂), and adenosine diphosphate (ADP) are some of the key agonists of platelet activation that are at the intersection between a plethora of inflammatory pathways that modulate pro-inflammatory and coagulation processes. The aim of this article is to review the role of platelets and the relationship between their structure, function, and the interactions of their constituents in systemic inflammation and atherosclerosis. Antiplatelet therapies are discussed with a view to primary prevention of CVD by the clinical reduction of platelet reactivity and inflammation. Current antiplatelet therapies are effective in reducing cardiovascular risk but increase bleeding risk. Novel therapeutic antiplatelet approaches beyond current pharmacological modalities that do not increase the risk of bleeding require further investigation. There is potential for specifically designed nutraceuticals that may become safer alternatives to pharmacological antiplatelet agents for the primary prevention of CVD but there is serious concern over their efficacy and regulation, which requires considerably more research.

PI3K inhibitors in thrombosis and cardiovascular disease

Phosphoinositide 3-kinases (PI3Ks) are lipid kinases that regulate important intracellular signalling and vesicle trafficking events via the generation of 3-phosphoinositides. Comprising eight core isoforms across three classes, the PI3K family displays broad expression and function throughout mammalian tissues, and the (patho)physiological roles of these enzymes in the cardiovascular system present the PI3Ks as potential therapeutic targets in settings such as thrombosis, atherosclerosis and heart failure. This review will discuss the PI3K enzymes and their roles in cardiovascular physiology and disease, with a particular focus on platelet function and thrombosis. The current progress and future potential of targeting the PI3K enzymes for therapeutic benefit in cardiovascular disease will be considered, while the challenges of developing drugs against these master cellular regulators will be discussed.

Biomarker-Based Preoperative Risk Stratification for Patients Undergoing Non-Cardiac Surgery

Perioperative morbidity and mortality remains a substantial problem and is strongly associated with patients’ cardiac comorbidities. Guidelines for the cardiovascular assessment and management of patients at risk of cardiac issues while undergoing non-cardiac surgery are traditionally based on the exclusion of active or unstable cardiac conditions, determination of the risk of surgery, the functional capacity of the patient, and the presence of cardiac risk factors. In the last two decades, strong evidence showed an association between cardiac biomarkers and adverse cardiac events, with newer guidelines incorporating this knowledge. This review describes a biomarker-based risk-stratification pathway and discusses potential treatment strategies for patients suffering from postoperative myocardial injury or infarction.

Monitoring Fondaparinux in the Setting of Antithrombin Deficiency

Heparin-induced thrombocytopenia (HIT) is a not-uncommon adverse effect of heparin exposure, with potentially serious and/or fatal thrombotic consequences. Recent studies looking at the off-label use of fondaparinux for HIT show similar efficacy and adverse-effect profiles, as well as improved costs, compared with some commonly used direct thrombin inhibitors. Although routine laboratory monitoring of fondaparinux-specific anti-Xa levels typically is not recommended, we present a case report that suggests fondaparinux monitoring may be needed in patients with hepatic impairment causing acquired antithrombin deficiency. We performed daily assessment of antithrombin- and fondaparinux-specific anti-Xa levels in a 50-year-old female of unknown ethnicity to ensure that fondaparinux dosing was maintained within an acceptable range. With this management strategy, the patient experienced no thrombotic or hemorrhagic complications during the hospital admission or the following 2 months in outpatient treatment.

Aspirin Before Elective Surgery-Stop or Continue?

BACKGROUND

Cessation of long-term aspirin treatment before noncardiac surgery can cause adverse cardiac events in patients at risk, particularly in those with previous percutaneous coronary interventions (PCI) with stent implantation. The factors influencing the clinical decision to stop aspirin treatment are currently unknown.

METHODS

In a single-center, cross-sectional study (retrospective registration: NCT03049566) carried out from February to December 2014, we took a survey among patients scheduled for noncardiac surgery who were under long-term aspirin treatment, and among their treating anesthesiologists using standardized questionnaires on preoperative aspirin use, comorbidities, and risk-benefit assessments. The main objective was to identify factors associated with the decision to stop aspirin treatment. The results of multivariable logistic regressions and intraclass correlations are presented.

RESULTS

805 patients were included in the study, and 636 questionnaires were returned (203 of which concerned patients with coronary stents). 46.8% of the patients stopped their long-term aspirin treatment before surgery; 38.7% of these patients stopped it too early (>10 days before surgery) or too late (≤ 3 days before surgery). A prior PCI with stent implantation lowered the probability of aspirin cessation (odds ratio [OR] = 0.47 [0.31; 0.72]; p <0.001). On the other hand, patients were more likely to stop their long-term aspirin treatment if it had already been discontinued once before (OR = 4.58 [3.06; 6.84]; p <0.001), if there was a risk of bleeding into a closed space (OR = 4.54 [2.02; 10.22]; p <0.001), if they did not know why they were supposed to take aspirin (OR = 2.12 [1.05; 4.28]; p = 0.036), or if the preoperative consultation with the anesthesiologist occurred <2 days before surgery (OR = 1.60 [1.08; 2.37]; p = 0.018). Patients often assessed the risks related to aspirin cessation lower than their physicians did.

CONCLUSION

This study reveals discordance between guideline recommendations and everyday clinical practice in patients with coronary stents. The early integration of cardiologists and anesthesiologists and a more widespread use of stent implant cards could promote adherence to the guidelines.

New anticoagulants, reversal agents, and clinical considerations for perioperative practice

There are several new anticoagulants on the market that will impact perioperative care, including the use of these anticoagulant drugs in the setting of regional anesthesia. The ideal pharmacological agent would prevent pathological thrombosis and allow for a normal response to vascular injury to limit bleeding. At present, all antithrombotic agents have increased bleeding risk as their main side effect. We describe the different categories of drugs, e.g., antiplatelet, anticoagulant, and thrombolytic, with particular emphasis on the new drugs that have been introduced into the market. These agents can be evaluated by a number of methods including low-, medium-, or high-risk procedures and guidelines and best practice standards that have been published regarding the amount of time to wait after stopping the medication and before performing a procedure, e.g., the American Society of Regional Anesthesia and Pain Medicine recommendations. The present investigation will also describe new reversal agents for anticoagulants and the implications of all these drugs for regional anesthesia.

Endothelial dysfunction and platelet hyperactivity in type 2 diabetes mellitus: molecular insights and therapeutic strategies

The incidence and prevalence of diabetes mellitus is rapidly increasing worldwide at an alarming rate. Type 2 diabetes mellitus (T2DM) is the most prevalent form of diabetes, accounting for approximately 90-95% of the total diabetes cases worldwide. Besides affecting the ability of body to use glucose, it is associated with micro-vascular and macro-vascular complications. Augmented atherosclerosis is documented to be the key factor leading to vascular complications in T2DM patients. The metabolic milieu of T2DM, including insulin resistance, hyperglycemia and release of excess free fatty acids, along with other metabolic abnormalities affects vascular wall by a series of events including endothelial dysfunction, platelet hyperactivity, oxidative stress and low-grade inflammation. Activation of these events further enhances vasoconstriction and promotes thrombus formation, ultimately resulting in the development of atherosclerosis. All these evidences are supported by the clinical trials reporting the importance of endothelial dysfunction and platelet hyperactivity in the pathogenesis of atherosclerotic vascular complications. In this review, an attempt has been made to comprehensively compile updated information available in context of endothelial and platelet dysfunction in T2DM.

Inhibition of platelet aggregation and thrombosis by indole alkaloids isolated from the edible insect Protaetia brevitarsis seulensis (Kolbe)

Protaetia brevitarsis seulensis (Kolbe) has been temporarily registered as a food material by the Ministry of Food and Drug Safety of Korea (MFDS). The current study aimed to discover small antithrombotic molecules from this edible insect. Five indole alkaloids, 5‐hydroxyindolin‐2‐one (1), (1R,3S)‐1‐methyl‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid (2), (1S,3S)‐1‐methyl‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid (3), (3S)‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid (4) and L‐tryptophan (5), were isolated from the insect. Among them, compounds 1 and 2 prolonged aPTT and PT and impaired thrombin and FXa generation on HUVEC surface. Moreover, these compounds inhibited platelet aggregation. Antithrombotic effects of compounds 1 and 2 were further confirmed in pre‐clinical models of pulmonary embolism and arterial thrombosis. Collectively, these results demonstrated that compounds 1 and 2 could be effective antithrombotic agents and serve as new scaffolds for the development of antithrombotic drug.