Monitoring of Antiplatelet Therapy

In the late 1990s, the antithrombotic antiplatelet agent, clopidogrel, a P2Y12 inhibitor, was introduced. Around the same time, there was an increase in a number of new methods to measure platelet function (e.g., PFA-100 in 1995), and this has continued. It became evident that not all patients responded to clopidogrel in the same way and that some patients had a relative "resistance" to therapy, termed "high on-treatment platelet reactivity." This then led to some publications to advocate platelet function testing being used for patients on antiplatelet therapy. Platelet function testing was also suggested for use in patients awaiting cardiac surgery after stopping their antiplatelet therapy as a way of balancing thrombotic risk pre-surgery and bleeding risk perioperatively. This chapter will discuss some of the commonly used platelet function tests used in these settings, particularly those that are sometimes referred to as point-of-care tests or that require minimal laboratory sample manipulation. The latest guidance and recommendations for platelet function testing will be discussed following several clinical trials looking at the usefulness of platelet function testing in these clinical settings.

Synthesis and Biological Evaluation of Novel Thiadiazole Derivatives as Antiplatelet Agents

A novel series of thiadiazole compounds was synthesized through the reaction of thiosemicarbazone intermediates with 2, 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The antiplatelet activity of the synthesized compounds was evaluated using an aggregation test with adenosine diphosphate (ADP) and arachidonic acid (AA) as platelet aggregation inducers. Among the synthesized analogs, compound 3b exhibited the most potent inhibition of platelet aggregation induced by ADP (half maximal inhibitory concentration [IC50] = 39 ± 11 µM). Molecular docking studies of 3b revealed hydrogen bonds between the nitrogen of the thiadiazole ring and Lys280. The tolyl ring exhibited hydrophobic interactions with Tyr105, similar to the antagonist co-crystallized with P2Y12 (PDB ID: 4NTJ). These compounds have the potential to serve as lead molecules for designing P2Y12 inhibitors.

Antithrombotic therapy after transcatheter aortic valve replacement

Aortic stenosis is a major valvular disease, which affects prognosis, and its prevalence is increasing due to an aging population. Transcatheter aortic valve replacement (TAVR) is a well-established therapy for symptomatic severe aortic stenosis across the entire risk spectrum, and the number of patients who undergo TAVR is increasing worldwide. Generally, ischemic and bleeding events after TAVR are not rare and can be devastating. Thus, antithrombotic therapy is recommended to prevent thromboembolic events after TAVR. Recently, a lot of randomized control trials have been published on antithrombotic therapy following TAVR, and the situation regarding the optimal antithrombotic regiment following TAVR is dramatically changing. This report reviews the current status and remaining issues in the field of optimal antithrombotic therapy following TAVR and leaflet thrombosis.

Influence of tirofiban on stroke outcome after mechanical thrombectomy in acute vertebrobasilar artery occlusion

BACKGROUND

Even undergoing mechanical thrombectomy (MT), patients with acute vertebrobasilar artery occlusion (AVBAO) still have a high rate of mortality. Tirofiban is a novel antiplatelet agent which is now widely empirically used in acute ischemic stroke (AIS). In this study, we aimed to evaluate the safety and efficacy of tirofiban as adjunctive therapy for MT in AVBAO.

METHODS

From October 2016 to July 2021, consecutive AVBAO patients receiving MT were included in the prospective stroke registry. The short-term outcomes were (1) symptomatic intracerebral hemorrhage (sICH); (2) in-hospital death; (3) National Institute of Health Stroke Scale (NIHSS) at discharge. The Long-term outcomes were: (1) modified Rankin Scale (mRS) at 3 months; (2) death at 3 months.

RESULTS

A total of 130 eligible patients were included in the study, 64 (49.2%) patients received tirofiban. In multivariate regression analysis, no significant differences were observed in all outcomes between the tirofiban and non-tirofiban group [sICH (adjusted OR 0.96; 95% CI, 0.12-7.82, p = 0.97), in-hospital death (adjusted OR 0.57; 95% CI, 0.17-1.89, p = 0.36), NIHSS at discharge (95% CI, -2.14-8.63, p = 0.24), mRS (adjusted OR 1.20; 95% CI, 0.40-3.62, p = 0.75), and death at 3 months (adjusted OR 0.83; 95% CI, 0.24-2.90, p = 0.77)].

CONCLUSIONS

In AVBAO, tirofiban adjunctive to MT was not associated with an increased risk of sICH. Short-term (in-hospital death, NIHSS at discharge) and long-term outcomes (mRS and death at 3 months) seem not to be influenced by tirofiban use.

Middle meningeal artery embolization for treatment of chronic subdural hematoma

BACKGROUND

Chronic subdural hematoma (cSDH) is caused by rupture of bridging intracranial veins located in the subdural space. Predominantly, cSDH is a disease of older adults and other predisposing risk factors include minor head trauma, cerebral atrophy, antiplatelet and anticoagulation therapies, arterial hypertension, cerebrovascular atherosclerosis, diabetes mellitus, cerebrospinal fluid loss, and excessive alcohol consumption. The incidence of cSDH is rising worldwide due to an aging population and the increased use of anticoagulant or antiplatelet medications. Clinical manifestations are varied, with altered mental status and focal neurologic deficits among the most common.

METHODOLOGICAL INNOVATIONS

Treatment strategies depend on the symptomatology and extent of hematoma. In general, conservative treatment is sought for patients who are asymptomatic or have only mild symptoms, whereas symptomatic patients are often treated surgically. However, the recurrence rate of cSDH may be as high as 30%. In recent years, middle meningeal artery embolization has emerged as a complementary option to surgery aimed at decreasing the recurrence rate after excision as well as an alternative therapeutic approach to surgical therapy in certain circumstances.

CONCLUSION

Embolization of the middle meningeal artery appears to be a promising treatment for patients with cSDH, both before and after surgical excision.

Safety of laparoscopic inguinal hernia repair in the setting of antithrombotic therapy

INTRODUCTION

There are a paucity of data regarding the safety of laparoscopic inguinal hernia repair in patients on antiplatelet and anticoagulant therapy (APT/ACT). We aim to compare the postoperative outcomes of laparoscopic (LIHR) vs. open repair of inguinal hernias (OIHR) in patients on APT/ACT.

METHOD

We conducted a retrospective cohort study using the Vizient Clinical DataBase. We included adults receiving APT/ACT who underwent outpatient, elective, and primary inguinal hernia repair between 2017 and 2019. Subgroup analysis was performed on patients receiving aspirin, non-aspirin antiplatelet, and anticoagulant therapy. Mixed-effects logistic regression was used to assess both the effect of APT/ACT on the probability of receiving LIHR vs OIHR and their respective outcomes.

RESULT

A total of 142,052 repairs were included, of which 21,441 (15%) were performed on patients receiving APT/ACT. Mean age was 69 years (± 10.5) and 93% were male. 19% of hernias were bilateral. 40% of operations were performed at teaching hospitals. On multivariable analysis, patients on non-aspirin antiplatelet or anticoagulant therapy were more likely to receive an open procedure (Odds Ratio (OR) = 1.2; 95% Confidence Intervals (CI) [1.1, 1.4] and OR = 1.4; CI [1.3, 1.5], respectively). LIHR was associated with a lower rate of length of stay > 1 day (OR = 0.65; CI [0.5, 0.9]). Rates of 30-day postoperative hematoma, transfusions, stroke, myocardial infarction, deep venous thrombosis, pulmonary embolism, readmission, and emergency department visits were similar between the two operative approaches.

CONCLUSION

Patients on APT/ACT represent a substantial proportion of those undergoing inguinal hernia repair. Non-aspirin antiplatelet or anticoagulant therapy are independent predictors of choosing an open repair. Laparoscopic repair appears to be safe in patients receiving APT/ACT under current perioperative management patterns.

The Prophylactic Use of Glycoprotein 2b/3a Inhibitors in the Endovascular Treatment of Intracranial Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND

There has been a growing interest in the use of Glycoprotein 2b/3a (GP2B3A) inhibitors in neuroendovascular procedures. However, clinical evidence for their prophylactic use is still sparse. In this review, we aimed to assess the safety and efficacy of prophylactic GP2B3A inhibitor use and to compare the performance of GP2B3A inhibitors with oral dual antiplatelet (DAP) treatment in intracranial aneurysm patients treated with stent-assisted coil embolization or flow diversion.

METHODS

A systematic literature search was conducted in Ovid MEDLINE, Ovid Embase, Scopus, Web of Science, and Cochrane Central Register of Clinical Trials databases. Data collected included hemorrhagic and thromboembolic complication rates, mortality, good functional outcome, and rupture status. A random-effects model was fit for each outcome measure.

RESULTS

Thirteen studies comprising 1429 patients were included. The overall hemorrhagic complication rate of the GP2B3A cohort was 3.98% (95% confidence interval [CI] = 1.58-7.42). The subgroup analysis comparing ruptured versus unruptured aneurysms in which GP2B3A antagonists were used did not show a significant difference in hemorrhagic complication rates (P-value = 0.504). Compared with the DAP group, the GP2B3A inhibitor cohort had significantly lower hemorrhagic complication rates (odds ratio = 0.33; 95% CI = 0.13-0.85; P-value = 0.022). The thromboembolic complication rates were 6.63% (95% CI = 3.44-10.75) for the GP2B3A inhibitor group and 10.4% (95% CI = 7-13.8) for the DAP group. However, the difference was not statistically significant (odds ratio = 0.52; 95% CI = 0.22-1.24; P-value = 0.142).

CONCLUSIONS

Our results support that GP2B3A inhibitors are safe and effective in preventing ischemic complications associated with the endoluminal devices. Additionally, our findings indicate that GP2B3A inhibitors can be utilized as prophylactic agents regardless of the rupture status.

The Impact of Preinjury Antiplatelet and Anticoagulant Use on Elderly Patients with Moderate or Severe Traumatic Brain Injury Following Traumatic Acute Subdural Hematoma

BACKGROUND

Although it is often assumed that preinjury anticoagulant (AC) or antiplatelet (AP) use is associated with poorer outcomes among those with acute subdural hematoma (aSDH), previous studies have had varied results. This study examines the impact of preinjury AC and AP therapy on aSDH thickness, 30-day mortality, and extended Glasgow Outcome Scale at 6 months in elderly patients (aged ≥65).

METHODS

A level 1 trauma center registry was interrogated to identify consecutive elderly patients who presented with moderate or severe traumatic brain injury (TBI) and associated traumatic aSDH between the first of January 2013 and the first of January 2018. Relevant demographic, clinical, and radiological data were retrieved from institutional medical records. The 3 primary outcome measures were aSDH thickness on initial computed tomography scan, 30-day mortality, and unfavorable outcome at 6 months (extended Glasgow Outcome Scale).

RESULTS

One hundred thirty-two elderly patients were admitted with moderate or severe TBI and traumatic aSDH. The mean (±SD) age was 78.39 (±7.87) years, and a majority of patients (59.8%, n = 79) were male. There was a statistically significant difference in mean aSDH thickness, but there were no significant differences in 30-day mortality (P = 0.732) and unfavorable outcome between the AP, AC, combined AP and AC, and no antithrombotic exposure groups (P = 0.342).

CONCLUSIONS

Further studies with larger sample sizes are necessary to confirm these observations, but our findings do not support the preconceived notion in clinical practice that antithrombotic use is associated with poor outcomes in elderly patients with moderate or severe TBI.

Verifynow P2Y12 PRU-Guided Modification of Clopidogrel for Prevention of Recurrent Ischemic Stroke: A Real-World Prospective Cohort Study

INTRODUCTION

Clopidogrel resistance causes recurrent stroke. However, outcomes of modified antiplatelet medications to prevent recurrent ischemic stroke are not well known.

METHODS

Patients who received clopidogrel with and without modification as initial treatment for stroke were recruited and compared. The primary outcome was ischemic stroke and myocardial infarction at the 1-year follow-up. The secondary outcome was bleeding complications.

RESULTS

Overall, 206 patients treated with clopidogrel were enrolled and were divided into the modification (n = 39) and no modification (n = 167) groups. There was a significant difference in the incidence of severe cerebral arterial stenosis between the two groups (modification group, 16/39, 41.03%; no modification group, 36/167, 21.56%, P = 0.012) at baseline. The loss to follow-up rate was 12.14% (25/206). After adjustment for severe cerebral artery stenosis, antiplatelet modification based on the platelet reactivity unit (PRU) value significantly improved in the per protocol set (odds ratio 0.142, 95% confidential interval 0.022-0.898, P = 0.038). The area under the curve of the different PRU cutoff values were 0.630, 0.605, and 0.591 (P = 0.016, 0.051, and 0.092) for PRU 190, 208, and 235, respectively.

CONCLUSION

Verifynow P2Y₁₂ PRU-guided modification of clopidogrel for ischemic stroke significantly improved or prevented recurrence at the 1-year follow-up. Our findings suggest that clopidogrel therapy based on the PRU cutoff value of 190 should be considered to improve outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02618265 (December 1, 2015).

The interplay between inflammation and thrombosis in COVID-19: Mechanisms, therapeutic strategies, and challenges

Coronavirus disease 2019 (COVID-19), caused by a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can cause life-threatening pathology characterized by a dysregulated immune response and coagulopathy. While respiratory failure induced by inflammation is the most common cause of death, micro-and macrovascular thrombosis leading to multiple organ failure are also causes of mortality. Dysregulation of systemic inflammation observed in severe COVID-19 patients is manifested by cytokine release syndrome (CRS) - the aberrant release of high levels of proinflammatory cytokines, such as IL-6, IL-1, TNFα, MP-1, as well as complement. CRS is often accompanied by activation of endothelial cells and platelets, coupled with perturbation of the balance between the pro-and antithrombotic mechanisms, resulting in thrombosis. Inflammation and thrombosis form a vicious circle, contributing to morbidity and mortality. Treatment of hyperinflammation has been shown to decrease thrombosis, while anti-thrombotic treatment also downregulates cytokine release. This review highlights the relationship between COVID-19-mediated systemic inflammation and thrombosis, the molecular pathways involved, the therapies targeting these processes, and the challenges currently encountered.

The role of CYP2C19 genotyping to guide antiplatelet therapy following ischemic stroke or transient ischemic attack

Introduction

Clopidogrel is an antiplatelet agent recommended for secondary prevention of ischemic stroke (IS) and transient ischemic attack (TIA). Conversion of clopidogrel to its active metabolite by hepatic cytochrome P450-2C19 (CYP2C19) is essential for the inhibition of the P2Y12 receptor and subsequent platelet aggregation to prevent thrombotic events. CYP2C19 is highly polymorphic, with over 30 loss of function (LoF) alleles. This review considers whether there is sufficient data to support genotype guided antiplatelet therapy after stroke.

Areas covered

A systematic literature review retrieved articles, which describe the interaction between CYP2C19 genotype and clinical outcomes following IS or TIA when treated with clopidogrel. The review documents efforts to identify optimal antiplatelet regimens and explores the value genotype guided antiplatelet therapy. The work outlines the contemporary understanding of clopidogrel metabolism and appraises evidence linking CYP2C19 LoF variants with attenuated platelet inhibition and poorer outcomes.

Expert opinion

There is good evidence that CYP2C19 LoF allele carriers of Han-Chinese ancestry have increased risk for further vascular events following TIA or IS when treated with clopidogrel. The evidence base is less certain in other populations. The expansion of pharmacogenetics into routine clinical practice will facilitate further research and help tailor other aspects of secondary prevention.

Pre-admission antithrombotic use is associated with 3-month mRS score after thrombectomy for acute ischemic stroke

In patients who undergo thrombectomy for acute ischemic stroke, the relationship between pre-admission antithrombotic (anticoagulation or antiplatelet) use and both radiographic and functional outcome is not well understood. We sought to explore the relationship between pre-admission antithrombotic use in patients who underwent thrombectomy for acute ischemic stroke at two medical centers in New York City between December 2018 and November 2020. Analyses were performed using analysis of variance and Pearson's chi-squared tests. Of 234 patients in the analysis cohort, 65 (28%) were on anticoagulation, 64 (27%) were on antiplatelet, and 105 (45%) with no antithrombotic use pre-admission. 3-month Modified Rankin Scale (mRS) score of 3-6 was associated with pre-admission antithrombotic use (71% anticoagulation vs. 77% antiplatelet vs. 56% no antithrombotic, p = 0.04). There was no relationship between pre-admission antithrombotic use and Thrombolysis in Cerebral Iinfarction (TICI) score, post-procedure Alberta Stroke Program Early CT Score (ASPECTS) score, rate of hemorrhagic conversion, length of hospital admission, discharge NIH Stroke Scale (NIHSS), discharge mRS score, or mortality. When initial NIHSS score, post-procedure ASPECTS score, and age at admission were included in multivariate analysis, pre-admission antithrombotic use was still significantly associated with a 3-month mRS score of 3-6 (OR 2.36, 95% CI 1.03-5.54, p = 0.04). In this cohort of patients with acute ischemic stroke who underwent thrombectomy, pre-admission antithrombotic use was associated with 3-month mRS score, but no other measures of radiographic or functional outcome. Further research is needed on the relationship between use of specific anticoagulation or antiplatelet agents and outcome after acute ischemic stroke, but moreover, improve stroke prevention.

New oral protease-activated receptor 4 antagonist BMS-986120: tolerability, pharmacokinetics, pharmacodynamics, and gene variant effects in humans

BMS-986120 is a novel first-in-class oral protease-activated receptor 4 (PAR4) antagonist exhibiting robust antithrombotic activity that has shown low bleeding risk in monkeys. We sought to assess pharmacokinetics, pharmacodynamics, and tolerability of BMS-986120 in healthy participants and platelet responses to BMS-986120 in participants carrying PAR4 A120T variants. Phase I, randomized, double-blind, placebo-controlled single-ascending-dose (SAD; N = 56) and multiple-ascending-dose (MAD; N = 32) studies were conducted. Exposure was approximately dose-proportional: maximum concentrations 27.3 and 1536 ng/mL, areas under the curve (AUC) to infinity of 164 and 15,603 h*ng/mL, and half-lives of 44.7 and 84.1 hours for 3.0 and 180 mg, respectively. The accumulation index suggested an ~2-fold AUC increase at steady state. Single doses of 75 and 180 mg BMS-986120 produced ≥80% inhibition of 12.5 μM PAR4 agonist peptide (AP)-induced platelet aggregation through at least 24 hours postdose, and doses ≥10 mg for ~7 days inhibited aggregation completely through 24 hours. No differences in PAR4-mediated platelet response were seen between AA120 versus TT120 PAR4 variants. In cells expressing A120 or T120 PAR4 proteins, no differences in half-maximal effective concentration in receptor activation by PAR4-AP were observed. BMS-986120 was well tolerated with dose-proportional pharmacokinetics and concentration-dependent pharmacodynamics in healthy participants over a wide dose range.ClinicalTrials.gov ID: NCT02208882.

P2Y12 Inhibitors versus Aspirin Monotherapy for Long-term Secondary Prevention of Atherosclerotic Cardiovascular Disease Events: A Systematic Review and Meta-analysis

BACKGROUND

Patients with established atherosclerotic cardiovascular disease (ASCVD) need long-term antiplatelet therapy to decrease the risk of future ASCVD events.

METHODS

We searched PubMed, Cochrane Library, and ClinicalTrials.gov (inception through September 2021) for randomized controlled trials (RCTs) evaluating P2Y₁₂ inhibitors versus aspirin for secondary prevention of ASCVD events.

RESULTS

Seven RCTs including a total of 56,982 patients were included in this analysis. The median follow-up duration was 22.8 (IQR 12) months. When P2Y₁₂ inhibitors were compared with aspirin as long-term antiplatelet therapy for secondary prevention of ASCVD events, there was a significant decrease in the risk of myocardial infarction [RR: 0.83; 95% CI: 0.72-0.94], and stroke [RR: 0.90; 95% CI: 0.83-0.99]. However, there was no significant difference in all-cause mortality [RR: 1.02; 95% CI: 0.92-1.12], or cardiovascular mortality [RR: 0.95; 95% CI: 0.83-1.08] between P2Y₁₂ inhibitors and aspirin users. Additionally, there was no significant difference in major bleeding events [RR: 0.88; 95% CI: 0.74-1.04], or all bleeding events [RR: 1.09; 95% CI: 0.90-1.33] between P2Y₁₂ inhibitors and aspirin groups.

CONCLUSION

Use of P2Y₁₂ inhibitor monotherapy is associated with lower rates of myocardial infarction and stroke in ASCVD patients without any significant difference in mortality, or bleeding compared to aspirin monotherapy.

Application of a TEG-Platelet Mapping Algorithm to Guide Reversal of Antiplatelet Agents in Adults with Mild-to-Moderate Traumatic Brain Injury: An Observational Pilot Study

BACKGROUND

Traumatic intracranial hemorrhages expand in one third of cases, and antiplatelet medications may exacerbate hematoma expansion. However, the reversal of an antiplatelet effect with platelet transfusion has been associated with harm. We sought to determine whether a thromboelastography platelet mapping (TEG-PM)-guided algorithm could limit platelet transfusion in patients with hemorrhagic traumatic brain injury (TBI) prescribed antiplatelet medications without a resultant clinically significant increase in hemorrhage volume, late hemostatic treatments, or delayed operative intervention.

METHODS

A total of 175 consecutive patients with TBI were admitted to our university-affiliated, level I trauma center between March 2016 and December 2019: 54 preintervention patients (control) and 121 patients with TEG-PM (study). After exclusion for anticoagulant administration, availability of neuroimaging and emergent neurosurgery, 62 study patients and 37 control patients remained. Intervention consisted of administration of desmopressin (DDAVP) for nonsurgical patients with significant inhibition at the arachidonic acid or adenosine diphosphate receptor sites. For surgical patients with significant inhibition, dual therapy with DDAVP and platelet transfusion was employed. Study patients were compared with a group of historical controls, which were identified from a prospectively maintained registry and typically treated with empiric platelet transfusion.

RESULTS

Median age was 75 years (interquartile range 85-67) and 77 years (interquartile range 81-65) in the TEG-PM and control patient groups, respectively. Admission hemorrhage volumes were similar (10.7 cm³ [20.1] in patients with TEG-PM vs. 14.1 cm³ [19.7] in controls; p = 0.41). There were no significant differences in admission Glasgow Coma Scale, mechanism of trauma, or baseline comorbidities. A total of 57% of controls versus 10% of patients with TEG-PM (p < 0.001) were transfused platelets; 52% of intervention patients and 0% controls were treated with DDAVP. Expansion hemorrhage volumes were not significantly different (14.0 cm³ [20.2] patients with TEG-PM versus 13.6 cm³ [23.7] controls; p = 0.93). There was no significant difference in rates of clinical deterioration, delayed neurosurgical intervention, or late platelet transfusion between groups.

CONCLUSIONS

Among patients with hemorrhagic TBI prescribed preinjury antiplatelet therapy, our study suggests that the use of a TEG-PM algorithm may reduce platelet transfusions without a concurrent increase in clinically significant hematoma expansion. Further study is required to prove a causative relationship.

High-sensitivity C-reactive protein as a better predictor of post-thrombolytic functional outcome in patients with previous antiplatelet therapy

Background

C-reactive protein (CRP) is an important biomarker of inflammation and plays a pivotal role in predicting the clinical prognosis of cardiovascular and cerebrovascular diseases. However, the mechanism of inflammation influencing the outcome of patients with ischemic stroke are unknown.

Aims

We aim to investigate the association between hsCRP and mRS in 194 eligible patients by therapy-stratified analyses.

Methods

The modification effects of antiplatelet therapy on the association between mRS and different exposure variables were analyzed. The retained variables were analyzed in the receiver operating characteristic (ROC) curve to discriminate patients with poor outcome.

Results

hsCRP was positively correlated with mRS in therapy-stratified analyses. There was a statistical modification effect of antiplatelet therapy on the association of hsCRP and mRS (P for interaction = 0.0101). The discriminative effect of poor outcome was further verified by ROC curve analyses (AUC_with from 0.758 to 0.872, AUC_without from 0.709 to 0.713).

Conclusions

hsCRP is correlated with the clinical outcome of patients treated with IVrt-PA, and may be a better predictor of post-thrombolytic functional outcome in patients with previous antiplatelet therapy than in non-used patients.

Antiplatelet Agents in Acute ST Elevation Myocardial Infarction

Platelet aggregation and thrombus formation represent the basic mechanism for clinical, electrocardiographic, and biomarker changes consistent with acute coronary syndrome. Various oral and intravenous formulations of platelet function inhibitors have been developed to help decrease platelet aggregation due to acute atherosclerotic plaque rupture. In this article, we review the various mechanisms, pharmacokinetics/pharmacodynamics, and the key clinical trials related to the platelet inhibitors that form the basis for current recommendations of their use in the ST elevation myocardial infarction guidelines by the American College of Cardiology/American Heart Association.

Editor's Choice - PRINciples of optimal antithrombotiC therapy and coagulation managEment during elective fenestrated and branched EndovaScular aortic repairS (PRINCE2SS): An International Expert Based Delphi Consensus Study

OBJECTIVE

Management of antithrombotic therapy in patients undergoing elective fenestrated branched endovascular aortic repair (F-BEVAR) is not standardised, nor are there any recommendations from current guidelines. By designing an international expert based Delphi consensus, the study aimed to create recommendations on the pre-, intra-, and post-operative management of antithrombotic therapy in patients scheduled for elective F-BEVAR in high volume centres.

METHODS

Eight facilitators created appropriate statements regarding the study topic that were voted on, using a four point Likert scale, by a selected panel of international experts using a three round modified Delphi consensus process. Based on the experts' responses, only those statements reaching Grade A (full agreement ≥ 75%) or B (overall agreement ≥ 80% and full disagreement < 5%) were included in the final document. The round answers' consistency was graded using Cohen's k, the intraclass correlation coefficient, and, in case of double re-submission, the Fleiss k.

RESULTS

Sixty-seven experts were included in the final analysis and voted the initial 43 statements related to pre- (n = 15), intra- (n = 10), and post-operative (n = 18) management of antithrombotic drugs. At the end of the process, six statements (13%) were rejected, 20 statements (44%) received a Grade B consensus, and 18 statements (40%) reached a Grade A consensus. Most statements (27; 71%) exhibited very high or high consistency grades, and 11 (29%) a fair or poor grading. The intra-operative statements mostly concentrated on threshold for and monitoring of proper heparinisation. The pre- and post-operative statements mainly focused on indications for dual antiplatelet therapy and its management, considering the possible need for cerebrospinal fluid drainage.

CONCLUSION

Based on the elevated strength and high consistency of this international expert based Delphi consensus, most of the statements might guide current clinical management of antithrombotic therapy for elective F-BEVAR. Future studies are needed to clarify the debated issues.

Emergency Cervical Carotid Artery Stenting After Intravenous Thrombolysis in Patients With Hyperacute Ischemic Stroke

BACKGROUND

Intravenous recombinant tissue plasminogen activator (IV rtPA) is the mainstay of treatment for acute ischemic stroke to recanalize thrombosed intracranial vessels within 4.5 hours. Emergency carotid artery stenting for the treatment of acute stroke due to steno-occlusion of the proximal internal carotid artery (ICA) can improve symptoms, prevent neurological deterioration, and reduce recurrent stroke risk. The feasibility and safety of the combination therapy of IV rtPA and urgent carotid artery stenting have not been established.

METHODS

From November 2005 to October 2020, we retrospectively assessed patients who had undergone emergent carotid artery stenting after IV rtPA for hyperacute ischemic stroke due to steno-occlusive proximal ICA lesion. Hemorrhagic transformation, successful recanalization, modified Rankin Scale (mRS) score at 90 days, and stent patency at 3 and 12 months or longer were evaluated. Favorable outcome was defined as a 90-days mRS score of ≤ 2.

RESULTS

Nineteen patients with hyperacute stroke had undergone emergent carotid artery stenting after IV rtPA therapy. Their median age was 70 (67.5-73.5) years (94.7% men). Among 15 patients with an additional intracranial occlusion after flow restoration in the proximal ICA, a modified TICI grade ≥ 2b was achieved in 11 patients (73.3%). Hemorrhagic transformation occurred in five patients (26.3%); mortality rate was 5.7%. Eleven patients (57.9%) had favorable outcomes at 90 days. Stent patients (94.1%) maintained stent patency for ≥ 12 months.

CONCLUSION

We showed that emergent carotid artery stenting after IV rtPA therapy for hyperacute stroke caused by atherosclerotic proximal ICA steno-occlusion was feasible and safe.

R558C NOTCH3 Mutation in a CADASIL Patient with Intracerebral Hemorrhage: A Case Report with Literature Review

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic cerebral small-vessel disease, which is characterized by migraine, recurrent ischemic strokes, psychiatric disorder, progressive cognitive decline, and occasionally intracerebral hemorrhage (ICH). ICH events have been reported in a high proportion of East Asian CADASIL patients with R544C mutation in exon 11 of NOTCH3; however, whether any other specific NOTCH3 mutation determines the ICH phenotype has yet to be explored.

CASE PRESENTATION

We report the case of a 60-year-old male CADASIL patient with a novel R558C mutation in exon 11 of the NOTCH3 gene, who presented with ICH in the basal ganglia and cerebellum. Brain imaging revealed multiple confluent white matter hyperintensities and abundant cerebral microbleeds (CMBs) in the bilateral basal ganglia, thalamus, and cerebellum. The patient had been having recurrent ischemic strokes prior to this ICH event, and had taken antiplatelet and antihypertensive agents for six months. We analyzed the possible reasons for ICH onset in the patient to recommend certain guidelines for the clinic.

CONCLUSIONS

Novel R558C mutation-related CADASIL vasculopathy and numerous CMBs, uncontrolled hypertension, and antiplatelet therapy could collectively contribute to ICH onset in the patient with CADASIL. These findings suggest that a diagnosis of CADASIL should also be considered when patients present with ICH, whenever MRI imaging reveals typical white matter abnormalities. Furthermore, this case report emphasizes the importance of CMB assessment, appropriate blood pressure control, and cautious assessment of the risk-benefits of antiplatelet medication in patients with CADASIL.

A pilot clinical study to Evaluate Liraglutide-mediated Anti-platelet activity in patients with type-2 Diabetes (ELAID study)

BACKGROUND

Liraglutide is an effective treatment for the management of type 2 diabetes mellitus (T2DM). In addition to glycemic control and potential cardioprotective effects, recent studies suggest a possible role for liraglutide in the inhibition of platelet reactivity, further attenuating atherothrombotic risk in patients with T2DM. We evaluated the in-vivo antiplatelet effect of liraglutide in T2DM patients without macrovascular disease or concurrent anti-platelet therapy.

METHODS

A double-blind, placebo-controlled pilot study of 16 T2DM patients, 51-69 y/o, (mean age 60.4 y/o, 63.0% male) randomised to receive liraglutide (1.8 mg/day) or placebo (saline) for 6 months was conducted. Platelet aggregation studies at baseline and after initiation of the study intervention: days 1, 7, and 14 and months 1, 3 and 6 were performed.

RESULTS

Liraglutide (n = 7) and placebo (n = 9) treated patients demonstrated normal platelet aggregation responses although transient and significant attenuation in maximum slope of platelet aggregation in response to collagen (p ≤ 0.05), arachidonic acid (p ≤ 0.05) and ADP (p ≤ 0.02) was observed in liraglutide compared to placebo treated patients in the first week.

CONCLUSIONS

In this pilot study of patients with T2DM liraglutide treatment was associated with a significant, early and transient decrease in maximum slope of platelet aggregation. The clinical significance of this effect is currently unknown and may warrant further investigation.

CLINICAL TRIAL REGISTRATION NUMBER

UTN 1111-1181-9567.

Prognostic impact of a history of cancer and atrial fibrillation in antithrombotic therapy for chronic heart failure

AIMS

This study aimed to examine the prognostic significance of a history of cancer and atrial fibrillation (AF) in antithrombotic therapy for patients with chronic heart failure (CHF).

METHODS AND RESULTS

We enrolled consecutive 4876 CHF patients (69 ± 12 years; women, 31.9%) in our multicentre, hospital-based cohort study, the Chronic Heart Failure Analysis and Registry in the Tohoku District-2 (CHART-2), with a median follow-up of 8.7 years. Among them, 14% and 41% had a history of cancer and AF, respectively. AF patients with a history of cancer were older, more frequently men. History of cancer was not statistically associated with higher rate of composite of stroke, systemic thrombosis, and major bleeding defined by International Society on Thrombosis and Haemostasis [Fine-Gray sub-distribution hazard ratio (sHR) accounting for the competing risk of all-cause death, 0.91; 95% confidence interval (CI), 0.56-1.48; P = 0.715]. The patients with history of cancer and AF had a heightened risk for the composite of stroke, systemic thrombosis, and major bleeding (sHR, 1.64; 95% CI, 1.04-2.60; P = 0.033), especially in those aged >75 years (sHR, 2.14; 95% CI, 1.01-4.53; P = 0.046) and those with ischaemic heart disease (IHD; 2.48; 1.30-4.72; P = 0.006). Furthermore, 36% of AF patients with a history of cancer did not receive anticoagulant therapy.

CONCLUSIONS

The CHF patients with history of cancer and AF had higher risk for stroke, systemic thrombosis, and major bleeding, especially in the elderly and those with IHD, but considerable number of the patients did not receive anticoagulant therapy, indicating the need for better optimal anticoagulation strategy.

Ticagrelor

Ticagrelor is one of the most recent antiplatelet agents used to inhibit platelet aggregation via blocking the ADP receptors of the subtype P2Y₁₂. It belongs to the non-thienopyridine class. The drug was first discovered by Astra Zeneca and approved for use in 2011 by the FDA. Ticagrelor is usually used for the prevention and treatment of thromboembolism in adult patients with acute coronary syndrome. This chapter include an overview on the physical properties, chemical properties, mode of action, pharmacokinetics and common uses of ticagrelor. In addition, the reported methods of ticagrelor assay will be discussed briefly in order to help analysts to find the most convenient method for its estimation in routine analysis. The methods of synthesis used for the preparation of ticagrelor will also be covered in this chapter. Moreover, the analytical and characterization techniques used to characterize ticagrelor row material are summarized herein.

Management of Antiplatelet and Anticoagulant Agents before and after Polypectomy

Antithrombotic medications, including antiplatelet drugs and anticoagulants, are widely prescribed to prevent thromboembolic disease. There is limited evidence informing gastroenterologists of the management of patients on antithrombotic medications undergoing colonoscopy and polypectomy. A patient's risk of thromboembolism versus postpolypectomy bleeding should be carefully considered, incorporating patient preferences concerning benefits and harms of temporary antithrombotic interruption. We will review the available consensus guidelines, current literature, and strategies to mitigate the risk of bleeding following polypectomy. These will be interpreted in the framework of shared decision-making with the patient to arrive at the safest solution best aligned with the patient's preferences.