Aspirin Desensitization and Percutaneous Coronary Intervention in a Patient with Aspirin Hypersensitivity and Acute Coronary Syndrome: A Case Report.

Hypersensitivity to aspirin is rare disorder occurring in 1.88% of the patients. Aspirin-hypersensitive patients requiring single antiplatelet agent may be treated with clopidogrel, an alternative antiplatelet agent. However, aspirin desensitization is more cost-effective than the usage of clopidogrel in these patients. Furthermore, aspirin desensitization is of greater value in patients requiring dual antiplatelet therapy, for example following procedures like percutaneous transluminal coronary angioplasty (PTCA) instead of using non-aspirin-based combinations. Herein, we report a 74-year-old hypertensive male presented with features of acute coronary syndrome and planned for percutaneous transluminal coronary angioplasty of RCA followed by dual antiplatelet therapy. Since he had aspirin allergy, desensitization was done using rapid desensitization protocol for which he responded well. This case highlights the importance of aspirin-desensitization in patients with aspirin allergy instead of choosing non-aspirin based antiplatelet agents.

Cost analysis of CYP2C19 genetic testing in percutaneous coronary intervention patients.

CYP2C19 loss of function (LOF) carriers undergoing percutaneous coronary intervention (PCI) have an increased risk of ischemic events when treated with clopidogrel. PCI patients in TAILOR-PCI were randomized to clopidogrel or genotype-guided (GG) therapy in which LOF carriers received ticagrelor and non-carriers clopidogrel. Direct medical costs associated with a GG approach have not been described before. TAILOR-PCI participants for whom direct medical costs were available for the duration from the date of PCI to one-year post PCI were included. Primary cost estimates were obtained from the Mayo Clinic Cost Data Warehouse. There were no differences in direct medical costs between the GG and clopidogrel groups (mean $20,682 versus $19,747, p = 0.11) however total costs were greater in the GG group (mean $21,245 versus $19,891, p = 0.02) which was primarily driven by ticagrelor costs. In conclusion the increased expense of a GG strategy post PCI as compared to clopidogrel for all is primarily driven by the cost of ticagrelor.

Elevated High-Sensitivity C-Reactive Protein Level Enhances the Impact of Lipoprotein(a) on Platelet Reactivity in PCI Patients Treated with Clopidogrel.

BACKGROUND: Recently, the effect of Lipoprotein(a) [Lp(a)] on thrombogenesis has aroused great interest, while inflammation has been reported to modify the Lp(a)-associated risks through an unidentified mechanism. PURPOSE: This study aimed to evaluate the association between platelet reactivity with Lp(a) and high-sensitivity C-reactive protein (hs-CRP) levels in percutaneous intervention (PCI) patients treated with clopidogrel. METHODS: Data were collected from 10,724 consecutive PCI patients throughout the year 2013 in Fuwai Hospital. High on-treatment platelet reactivity (HTPR) and low on-treatment platelet reactivity (LTPR) were defined as thrombelastography (TEG) maximum amplitude of adenosine diphosphate-induced platelet (MAADP) > 47 mm and < 31 mm, respectively. RESULTS: 6615 patients with TEG results were finally enrolled. The mean age was 58.24 ± 10.28 years and 5131 (77.6%) were male. Multivariable logistic regression showed that taking Lp(a) < 30 mg/dL and hs-CRP < 2 mg/L as the reference, isolated Lp(a) elevation [Lp(a) ≥ 30 mg/dL and hs-CRP < 2 mg/L] was not significantly associated with HTPR (P = 0.153) or LTPR (P = 0.312). However, the joint elevation of Lp(a) and hs-CRP [Lp(a) ≥ 30 mg/dL and hs-CRP ≥ 2 mg/L] exhibited enhanced association with both HTPR (OR:1.976, 95% CI 1.677-2.329) and LTPR (OR:0.533, 95% CI 0.454-0.627). CONCLUSIONS: The isolated elevation of Lp(a) level was not an independent indicator for platelet reactivity, yet the concomitant elevation of Lp(a) and hs-CRP levels was significantly associated with increased platelet reactivity. Whether intensified antiplatelet therapy or anti-inflammatory strategies could mitigate the risks in patients presenting combined Lp(a) and hs-CRP elevation requires future investigation.

A retrospective study of the safety and efficacy of clopidogrel versus aspirin monotherapy one year after coronary stent implantation.

BACKGROUND: The ideal single antiplatelet therapy for long-term maintenance after coronary stenting remains uncertain. In a head-to-head comparison, we aimed to evaluate the efficacy and safety profile of aspirin and clopidogrel as monotherapies in this patient cohort. METHOD: We reviewed 1044 patients who underwent percutaneous coronary intervention (PCI) with drug-eluting stents (DES) at the Department of Cardiovascular Medicine, Jinshan Hospital of Fudan University, between January 2019 and December 2021 and completed a 12-month Dual Antiplatelet Therapy (DAPT) treatment. They were divided into two groups: 582 were assigned to the aspirin group (100 mg/day) and 422 to the clopidogrel group (75 mg/day). The primary endpoint was the composite cardiac death, ischemic stroke, myocardial infarction, and Bleeding Academic Research Consortium (BARC) bleeding type 3 or greater. Secondary endpoint events included all-cause death, ischemic stroke, myocardial infarction, bleeding (defined as a BARC type ≥ 2 bleeding), and gastrointestinal complications. RESULTS: After a mean observation period of 25 ± 8.4 months, the primary endpoint event occurred in 29 (6.8%) patients in the clopidogrel group and 30 (5.1%) in the aspirin group, with no difference between the two groups (P = 0.253). In BARC type 2 or greater bleeding events, there were 9 (1.5%) in the aspirin group compared to 7 (1.7%) in the clopidogrel group, with no difference between the two groups (P = 0.160). CONCLUSION: After 12-month DAPT in Chinese patients undergoing DES implantation, aspirin monotherapy versus clopidogrel monotherapy showed no significant difference between the two drugs in terms of safety and efficacy in terms of hemorrhage, myocardial infarction, ischemic stroke, cardiac death, and bleeding with BARC type 2 or greater.

Genetic Determinants of Response to P2Y12 Inhibitors and Clinical Implications.

The CYP2C19 enzyme metabolizes clopidogrel, a prodrug, to its active form. Approximately 30% of individuals inherit a loss-of-function (LoF) polymorphism in the CYP2C19 gene, leading to reduced formation of the active clopidogrel metabolite. Reduced clopidogrel effectiveness has been well documented in patients with an LoF allele following an acute coronary syndrome or percutaneous coronary intervention. Prasugrel or ticagrelor is recommended in those with an LoF allele as neither is affected by CYP2C19 genotype. Although data demonstrate improved outcomes with a CYP2C19-guided approach to P2Y12 inhibitor selection, genotyping has not yet been widely adopted in clinical practice.

Comparison of clinical outcomes between ticagrelor and clopidogrel in patients with acute coronary syndrome and left ventricle dysfunction undergoing percutaneous coronary intervention: An observational study.

Patients with acute coronary syndrome (ACS) and left ventricular (LV) dysfunction undergoing percutaneous coronary intervention (PCI) need adequate antithrombotic protection. We aim to compare the clinical outcomes between ticagrelor and clopidogrel in these patients. In total, 336 patients with ACS and LV dysfunction who undergoing PCI were included in this retrospective observational study. Of these, 137 received clopidogrel and 199 received ticagrelor. There was a 6-month follow-up period during which clinical outcomes were monitored. The incidence of the composite endpoint (23.1% vs 13.9%, P = .041) and bleeding events (6.5% vs 1.5%, P = .027) in the ticagrelor group were significantly higher compared to the clopidogrel group. Multivariate logistic regression analysis revealed that age (P = .006), hypertension (P = .007), liver insufficiency (P = .022), previous MI (P = .014) and ticagrelor (P = .044) were independent risk factors that affect the efficacy outcome. Age (P = .027) and ticagrelor (P = .016) were the independent risk factors for the safety outcome. Furthermore, in Cox survival regression analysis model, the survival rate of the efficacy endpoint in the clopidogrel group was seemingly higher than in the ticagrelor group (HR = 1.68, 95% CI: 0.97-2.90, P = .065). The survival rate of the bleeding endpoint in the clopidogrel group was higher than in the ticagrelor group (HR = 2.00, 95% CI: 1.17-3.40, P = .011). Compared to clopidogrel, ticagrelor showed increased risk of efficacy outcome and major bleeding events during 6-month follow-up in patients with ACS and LV dysfunction undergoing PCI.

[Relationship between clopidogrel resistance and genetic variability in Kawasaki disease children with coronary artery lesions].

Objective: To analyze the distribution of clopidogrel metabolism-related gene variability in Kawasaki disease (KD) children with coronary artery lesions (CAL) across different age groups and the impact of genetic variability on the efficacy of clopidogrel antiplatelet therapy. Methods: A retrospective cohort study was conducted. Clinical data were collected from 46 KD children with CAL who were hospitalized in the Cardiovascular Center of Children's Hospital of Fudan University between January 2021 and August 2022 and were treated with clopidogrel, including gender, age, body mass index, course of KD, CAL severity grade, and baseline platelet count. According to their age, the children were divided into ≥2-year-old group and <2-year-old group. Their platelet responsiveness was assessed by adenosine diphosphate-induced platelet inhibition rate (ADPi) calculated via thromboelastography, and children were categorized into high on-treatment platelet reactivity (HTPR) and normal on-treatment platelet reactivity (NTPR) groups. Genotypes of CYP2C19, PON1 and ABCB1 were detected. The t test, one-way analysis of variance and Chi-square test were used for intergroup comparison. Results: Among the 46 KD children with CAL, 34 were male and 12 were female; 37 were ≥2-year-old and 9 were <2-year-old; 25 cases were in the HTPR group and 21 cases were in the NTPR group, with 19 HTPR and 18 NTPR in the ≥2-year-old group, and 6 HTPR and 3 NTPR in the <2-year-old group. Genetic analysis showed that 92 alleles among the 46 children, with frequencies of CYP2C19*1, CYP2C19*2, CYP2C19*3, CYP2C19*17, PON1 192Q, PON1 192R, ABCB1 3435C, ABCB1 3435T at 59% (54/92), 32% (29/92), 9% (8/92), 1% (1/92), 36% (36/92), 64% (59/92), 63% (58/92) and 37% (34/92), respectively. Analysis of the impact of genotype on ADPi revealed that in children aged ≥2 years, those with CYP2C19*1/*3 genotype had significantly lower ADPi than those with CYP2C19*1/*1 genotype ((34±15)% vs. (61±29)%, t=2.18, P=0.036). There were also no significant difference in ADPi among children with PON1 192Q homozygous, PON1 192R heterozygote and PON1 192R homozygous genotypes ((40±22)% vs. (52±33)% vs. (65±27)%, F=2.17, P=0.130), or among those with ABCB1 3435C homozygous, ABCB1 3435T heterozygote and ABCB1 3435T homozygous genotypes ((55±34)% vs. (60±27)% vs. (49±24)%, F=0.33, P=0.719). In <2-year-old group, there were no significant differences in ADPi across CYP2C19*1/*1, CYP2C19*1/*2 and CYP2C19*2*2 genotypes ((40±20)% vs. (53±37)% vs. (34±16)%, F=0.37, P>0.05). There were no significant differences in ADPi across CYP2C19*1/*1 and CYP2C19*1/*3 genotypes ((44±27)% vs. (42±20)%, t=0.08, P>0.05). There were no significant differences in ADPi across PON1 192Q homozygous, PON1 192R heterozygote and PON1 192R homozygous genotypes (45% vs. (55±27)% vs. (24±5)%, F=1.83, P>0.05). There were no significant differences in ADPi across ABCB1 3435C homozygous, ABCB1 3435T heterozygote and ABCB1 3435T homozygous genotypes ((36±16)% vs. (50±35)% vs. 45%, F=0.29, P>0.05). The risk analysis of HTPR in different genotypes revealed that in children aged ≥2 years, carrying at least 1 or 2 loss-of-function alleles of CYP2C19 was a risk factor for HTPR (OR=4.69, 10.00, 95%CI 1.11-19.83, 0.84-119.32, P=0.033, 0.046, respectively), and PON1 192R homozygosity and carrying at least one PON1 192R allele were protective factors against HTPR (OR=0.08, 0.13, 95%CI 0.01-0.86, 0.01-1.19, P=0.019, 0.043, respectively). Conclusion: KD children aged ≥2 years carrying CYP2C19 loss-of-function alleles and PON1 192Q are more likely to develop HTPR.

Clopidogrel and Aspirin Initiated Between 24 to 72 Hours for Mild Ischemic Stroke: A Subgroup Analysis of the INSPIRES Randomized Clinical Trial.

Importance: Prior trials showed that dual antiplatelet therapy could reduce the risk of early new stroke in patients with acute mild ischemic stroke or transient ischemic attack (TIA) within 24 hours of symptom onset. However, it is currently uncertain whether dual antiplatelet therapy can reduce the risk of early new stroke in patients with a more delayed initiation time window. Objective: To evaluate the efficacy and safety of clopidogrel and aspirin among patients with mild ischemic stroke or TIA when initiated within 24 hours, from more than 24 hours to 48 hours, and from more than 48 hours to 72 hours. Design, Setting, and Participants: The Intensive Statin and Antiplatelet Therapy for Acute High-Risk Intracranial or Extracranial Atherosclerosis randomized clinical trial was a double-blind, placebo-controlled, multicenter, 2-by-2 factorial randomized clinical trial conducted at 222 hospitals in China from September 17, 2018, to October 15, 2022. All patients with acute mild ischemic stroke and TIA were included in this subgroup analysis and categorized into 3 groups according to time from symptom onset to randomization (group 1: ≤24 hours; group 2: >24 to ≤48 hours; and group 3: >48 to 72 hours). Patients were followed up for 90 days. Interventions: All patients received clopidogrel combined with aspirin (clopidogrel 300 mg loading dose on day 1, followed by 75 mg daily on days 2 to 90, and aspirin 100 to 300 mg on the first day and then 100 mg daily for days 2 to 90) or aspirin alone (100 to 300 mg on day 1 and then 100 mg daily for days 2 to 90) within 72 hours after symptom onset. Main Outcomes and Measures: The primary outcome was new stroke (ischemic or hemorrhagic) within 90 days. The primary safety outcome was moderate-to-severe bleeding, according to Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries criteria. Results: This analysis included a total of 6100 patients (3050 in the clopidogrel-aspirin group and 3050 in the aspirin group). The median age was 65 years (IQR, 57-71 years), and 3915 patients (64.2%) were male. In the population with time to randomization of 24 hours or less, stroke occurred in the next 90 days in 97 of 783 patients (12.4%); among those randomized from more than 24 hours to 48 hours, in 211 of 2552 patients (8.3%) among those randomized from more than 24 hours to 48 hours, and in 193 of 2765 patients (7.0%). The clopidogrel-aspirin group had a lower risk of new stroke within 90 days compared with the aspirin alone group both in patients with time to randomization of from 48 to 72 hours (5.8% vs 8.2%; hazard ratio [HR], 0.70 [95% CI, 0.53-0.94]), of more than 24 to 48 hours (7.6% vs 8.9%; HR, 0.85 [95% CI, 0.65-1.12]), and of 24 hours or less (11.5% vs 13.4%; HR, 0.83 [95% CI, 0.55-1.25]) (P = .38 for interaction). Among those with time to randomization of more than 48 to 72 hours, moderate-to-severe bleeding occurred in 12 patients (0.9%) in the clopidogrel-aspirin group and in 6 patients (0.4%) in the aspirin-alone group (HR, 2.00 [95% CI, 0.73-5.43]), while moderate-to-severe bleeding in those with time to randomization of more than 24 hours to 48 hours occurred in 9 patients (0.7%) in the clopidogrel-aspirin group and in 4 patients (0.3%) in the aspirin-alone group (HR, 2.25 [95% CI, 0.68-7.39]) and in those with time to randomization of within 24 hours, occurred in 6 patients (1.5%) in the clopidogrel-aspirin group and in 3 patients (0.8%) in the aspirin-alone group (HR, 1.57 [95% CI, 0.36-6.83]) (P = .92 for interaction). Conclusions and Relevance: In this randomized clinical trial of antiplatelet therapy in China, patients with mild ischemic stroke or TIA had consistent benefit from dual antiplatelet therapy with clopidogrel and aspirin vs aspirin alone when initiated within 72 hours after symptom onset, with a similar increase in the risk of moderate-to-severe bleeding. Patients should receive dual antiplatelet therapy with clopidogrel and aspirin within 72 hours after symptom onset. Trial Registration: ClinicalTrials.gov Identifier: NCT03635749.

High Frequency of CYP2C19*3 Heterozygotes Among Patients Under Clopidogrel Treatment in Ouagadougou, Burkina Faso.

<b>Background and Objective:</b> Despite its widespread use in cardiology, patient's response to clopidogrel exhibits significant interindividual variability, often leading to persistent thromboembolic complications. The hepatic Cytochrome P450 2C19 (CYP2C19) superfamily plays a pivotal role in clopidogrel's conversion to its active form and CYP2C19 polymorphisms significantly contribute to this variability. This study aimed to evaluate the prevalence and impact of the CYP2C19 rs4986893 polymorphism on clopidogrel treatment response. <b>Materials and Methods:</b> Seventy-three patients with Cardiovascular Diseases (CVD) undergoing clopidogrel antiplatelet therapy for a minimum of six months were recruited from Centre Hospitalier Universitaire Yalgado Ouédraogo (CHU-YO). Sociodemographic data were collected and DNA was extracted from blood samples for CYP2C19 rs4986893 genotyping using PCR-RFLP. <b>Results:</b> The patient's mean age was 62.56±13.45 years, ranging from 23 to 94 years, with a male-to-female sex ratio of 1.28. Most patients came from the informal sector, primarily of Mossi ethnicity and residing in Ouagadougou. Acute coronary syndromes (ACS) and hypertension were the predominant reasons for consultation, with clopidogrel showing efficacy in 97.3% of cases. While 72.6% had no family history of CVD, hypertension was prevalent among those with familial cardiovascular conditions. Genetic analysis revealed a 65.8% frequency of heterozygotes CYP2C19*1/*3, with no mutant homozygotes CYP2C19*3/*3 detected. The results of the present study underscore a high prevalence of heterozygotes CYP2C19*1/*3 among patients with cardiovascular diseases. <b>Conclusion:</b> This intermediate metabolic phenotype, along with a good response to clopidogrel, suggests that CYP2C19*1/*3 genotype promotes a favourable response to clopidogrel therapy.

Dual Antiplatelet Therapy and Outcomes in Acute Mild to Moderate Stroke With Versus Without Large-Artery Atherosclerosis Post Hoc Analysis of ATAMIS.

BACKGROUND: We conducted a post hoc analysis of the ATAMIS (Antiplatelet Therapy in Acute Mild to Moderate Ischemic Stroke) trial to investigate whether the priority of clopidogrel plus aspirin to aspirin alone was consistent between patients with and without stroke pathogenesis of large-artery atherosclerosis (LAA). METHODS AND RESULTS: Patients with stroke classification randomized to a clopidogrel-plus-aspirin group and aspirin-alone group in a modified intention-to-treat analysis set of ATAMIS were classified into LAA and non-LAA subtypes. The primary outcome was early neurologic deterioration at 7 days, defined as a >2-point increase in National Institutes of Health Stroke Scale score compared with baseline, and safety outcomes were bleeding events and intracranial hemorrhage. We compared treatment effects in each stroke subtype and investigated the interaction. Among 2910 patients, 225 were assigned into the LAA subtype (119 in the clopidogrel-plus-aspirin group and 106 in the aspirin-alone group) and 2685 into the non-LAA subtype (1380 in the clopidogrel-plus-aspirin group and 1305 in the aspirin-alone group). Median age was 66 years, and 35% were women. A lower proportion of early neurologic deterioration was found to be associated with dual antiplatelet therapy in the LAA subtype (adjusted risk difference, -10.4% [95% CI, -16.2% to -4.7%]; P=0.001) but not in the non-LAA subtype (adjusted risk difference, -1.4% [95% CI, -2.6% to 0.1%]; P=0.06). No significant interaction was found (P=0.11). CONCLUSIONS: Compared with the non-LAA subtype, patients with stroke of the LAA subtype may get more benefit from dual antiplatelet therapy with clopidogrel plus aspirin with respect to early neurologic deterioration at 7 days. REGISTRATION: URL: clinicaltrials.gov; UnIque identifier: NCT02869009.

Clopidogrel Versus Aspirin as Chronic Maintenance Antiplatelet Monotherapy in Patients After Percutaneous Coronary Intervention With Chronic Kidney Disease: A Post Hoc Analysis of the HOST-EXAM Trial.

BACKGROUND: Clopidogrel monotherapy improved clinical outcomes compared with aspirin monotherapy during a chronic maintenance period in patients who underwent coronary stenting in the HOST-EXAM (Harmonizing Optimal Strategy for Treatment of Coronary Artery Stenosis-Extended Antiplatelet Monotherapy) trial. However, it is uncertain whether the beneficial effect of clopidogrel over aspirin is different according to the renal function. METHODS AND RESULTS: We conducted a post hoc analysis of the HOST-EXAM trial. Chronic kidney disease (CKD) was defined as baseline estimated glomerular filtration rate <60 mL/min per 1.73 m2. The primary end point was a composite of all-cause death, nonfatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and Bleeding Academic Research Consortium bleeding type ≥3, during the 2-year follow up. Among the 5438 patients enrolled in the HOST-EXAM trial, 4844 patients (mean age, 63.3±10.6 years; 74.9% men) with a baseline creatinine value were analyzed in this study. A total of 508 (10.5%) patients had CKD, who were at higher risk of the primary end point compared with those without CKD (hazard ratio [HR], 2.01 [95% CI, 1.51-2.67]). Clopidogrel monotherapy was associated with a lower rate of the primary end point in both patients with CKD (HR, 0.74 [95% CI, 0.44-1.25]) and patients without CKD (HR, 0.71 [95% CI, 0.56-0.91]). No significant interaction was observed between the treatment effect and CKD status (P for interaction=0.889). CONCLUSIONS: During the chronic maintenance period after coronary stenting, the risk of thrombotic and bleeding events was significantly higher in patients with CKD compared with those without CKD. There was no statistical difference in the treatment effect of clopidogrel monotherapy in those with versus without CKD.

Aspirin-clopidogrel combination therapy for ischemic stroke patients: Clinical efficacy and cost-effectiveness analyses in low-resource setting.

Understanding the cost-effectiveness of aspirin-clopidogrel combination therapy is crucial in determining its influence on coagulation parameters, specifically prothrombin time (PT) and activated partial thromboplastin time (APTT). The aim of this study was to assess the cost-effectiveness and clinical impact of using the aspirin-clopidogrel combination compared to aspirin alone in managing ischemic stroke. Employing an observational research design, inpatient ischemic stroke cases receiving the aspirin-clopidogrel combination were compared to those treated with aspirin alone. Focusing on the hospital's perspective on costs, the research specifically analyzed medical expenses without discounting costs or effects. The analysis involved comparing the direct medical costs and coagulation parameters between the two treatment groups. Our data revealed that the aspirin-clopidogrel combination demonstrated superior cost-effectiveness over aspirin alone, indicated by the incremental cost-effectiveness ratio (ICER) values for PT (IDR -246,930/second) and APTT (IDR -119,270/second). This indicated that the combination therapy was associated with lower costs while yielding better clinical parameter values. The ICER analysis placed the aspirin-clopidogrel combination in the southeast quadrant, marking its dominance over aspirin monotherapy by demonstrating higher effectiveness at lower costs. These results suggest that combination therapy might be a favorable alternative for managing ischemic stroke, presenting a viable option for consideration in clinical practice. The findings underscore the potential economic and clinical advantages of employing the aspirin-clopidogrel combination in routine stroke management protocols.

The prognostic difference study on the individualized clopidogrel administration in Hmong and Dong patients based on the CYP2C19 gene polymorphism after percutaneous coronary intervention.

This study explored the distribution characteristics of CYP2C19 gene polymorphism among Hmong and Dong patients in the Qiandongnan region of Guizhou province after percutaneous coronary intervention (PCI). The aim was to assess the clinical impact of individualized clopidogrel administration based on CYP2C19 genotypes. A total of 208 patients were classified into ultra-fast, fast, intermediate, and slow metabolic groups. They were randomly assigned to clopidogrel individualized administration (IA) or conventional treatment (CA) groups. Patients were followed for 6 months to evaluate major adverse cardiovascular events (MACE) and adverse reactions. The CYP2C19 genotype distribution was in Hardy-Weinberg equilibrium, showing consistency in the population. While no significant ethnic differences were found in genotype and metabolic distribution, allele distribution varied, with Hmong patients exhibiting a higher proportion of CYP2C19*1 alleles than Dong patients. Following individualized administration, the IA group demonstrated lower incidences of non-fatal myocardial infarction and emergency revascularization compared to the CA group. Bleeding events were higher in the IA group, but the total MACE incidence was lower. No statistical difference in MACE and adverse drug reactions (ADR) was observed in the CA group across metabolic types, but MACE incidence was higher in intermediate and slow metabolic groups. In the IA group, no significant difference in MACE was noted among metabolic types, but ADR incidence varied significantly, particularly in dyspnea. The study highlighted significant CYP2C19 allele distribution differences between Hmong and Dong patients post-PCI in Qiandongnan. Patients with slow metabolic profiles demonstrated higher MACE incidence with conventional clopidogrel dosage, whereas CYP2C19-guided therapy reduced MACE without increasing bleeding risk. These findings supported clinical individualized clopidogrel administration in post-PCI patients in the Qiandongnan region, contributing to rational clopidogrel use.

Duration of Benefit and Risk of Dual Antiplatelet Therapy up to 72 Hours After Mild Ischemic Stroke and Transient Ischemic Attack.

BACKGROUND AND OBJECTIVES: Clopidogrel-aspirin initiated within 72 hours of symptom onset is effective in patients with mild ischemic stroke or transient ischemic attack (TIA) in the Intensive Statin and Antiplatelet Therapy for Acute High-risk Intracranial or Extracranial Atherosclerosis (INSPIRES) trial. Uncertainties remain about the duration of the treatment effect. This study aimed to assess duration of benefit and risk of clopidogrel-aspirin in these patients. METHODS: The INSPIRES trial was a 2*2 factorial placebo-controlled randomized trial conducted in 222 hospitals in China. The 2 treatments did not interact and were evaluated separately. In this study, we performed secondary analyses based on antiplatelet treatment. All patients with mild stroke or TIA of presumed atherosclerotic cause within 72 hours of symptom onset enrolled in the trial were included. Patients were randomly assigned to receive clopidogrel-aspirin on days 1-21 followed by clopidogrel on days 22-90 or aspirin alone for 90 days. The primary efficacy outcome was major ischemic event which included the composite of ischemic stroke and nonhemorrhagic death. The primary safety outcome was moderate-to-severe bleeding. We estimated the risk difference between the 2 treatments for each stratified week. RESULTS: All 6,100 patients in the trial were included (3,050 in each group). The mean age was 65 years, and 3,915 patients (64.2%) were men. Compared with aspirin alone, the reduction of major ischemic events by clopidogrel-aspirin mainly occurred in the first week (absolute risk reduction [ARR] 1.42%, 95% CI 0.53%-2.32%) and remained in the second week (ARR 0.49%, 95% CI 0.09%-0.90%) and the third week (ARR 0.29%, 95% CI -0.05% to 0.62%). Numerical higher risk of moderate-to-severe bleedings in the clopidogrel-aspirin group was observed in the first 3 weeks (absolute risk increase 0.05% [95% CI -0.10% to 0.20%], 0.10% [95% CI -0.09% to 0.29%], and 0.18% [95% CI -0.03% to 0.40%] in the first, second, and third weeks, respectively). CONCLUSIONS: Among patients with mild ischemic stroke or high-risk TIA of presumed atherosclerotic cause, the net benefit of clopidogrel-aspirin initiated within 72 hours of symptom onset was pronounced in the first week and continued to a lesser degree in the following 2 weeks, outweighing the low, but ongoing hemorrhagic risk. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier: NCT03635749. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that among patients with mild ischemic stroke or high-risk TIA of presumed atherosclerotic cause, the net benefit of clopidogrel-aspirin initiated within 72 hours of symptom onset was pronounced in the first week and continued to a lesser degree in the following 2 weeks, outweighing the low but ongoing hemorrhagic risk.

Implementing a pharmacogenomic-driven algorithm to guide antiplatelet therapy among Caribbean Hispanics: a non-randomised clinical trial.

OBJECTIVES: To assess whether genotype-guided selection of oral antiplatelet drugs using a clinical decision support (CDS) algorithm reduces the rate of major adverse cardiovascular and cerebrovascular events (MACCEs) among Caribbean Hispanic patients, after 6 months. DESIGN: An open-label, multicentre, non-randomised clinical trial. SETTING: Eight secondary and tertiary care hospitals (public and private) in Puerto Rico. PARTICIPANTS: 300 Caribbean Hispanic patients on clopidogrel, both genders, underwent percutaneous coronary intervention (PCI) for acute coronary syndromes, stable ischaemic heart disease and documented extracardiac vascular diseases. INTERVENTIONS: Patients were separated into standard-of-care (SoC) and genotype-guided (pharmacogenetic (PGx)-CDS) groups (150 each) and stratified by risk scores. Risk scores were calculated based on a previously developed CDS risk prediction algorithm designed to make actionable treatment recommendations for each patient. Individual platelet function, genotypes, clinical and demographic data were included. Ticagrelor was recommended for patients with a high-risk score ≥2 in the PGx-CDS group only, the rest were kept or de-escalated to clopidogrel. The intervention took place within 3-5 days after PCI. Adherence medication score was also measured. PRIMARY AND SECONDARY OUTCOMES: The occurrence rate of MACCEs (primary) and bleeding episodes (secondary). Statistical associations between patient time free of events and predictor variables (ie, treatment groups, risk scores) were tested using Kaplan-Meier survival analyses and Cox proportional-hazards regression models. RESULTS: The genotype-guided group had a clinically lower but not significantly different risk of MACCEs compared with the SoC group (8.7% vs 10.7%, p=0.56; HR=0.56). Among high-risk score patients, genotype-driven guidance of antiplatelet therapy showed superiority over SoC in reducing MACCE incidence 6 months postcoronary stenting (adjusted HR=0.104; p< 0.0001). CONCLUSIONS: The potential benefit of implementing our PGx-CDS algorithm to significantly reduce the incidence rate of MACCEs in post-PCI Caribbean Hispanic patients on clopidogrel was observed exclusively among high-risk patients, with apparently no evident effect in other patient groups. TRIAL REGISTRATION NUMBER: NCT03419325.

Evaluation of pharmacogenetic automated clinical decision support for clopidogrel.

Aim: Clopidogrel requires CYP2C19 activation to have antiplatelet effects. Pharmacogenetic testing to identify patients with impaired CYP2C19 function can be coupled with clinical decision support (CDS) alerts to guide antiplatelet prescribing. We evaluated the impact of alerts on clopidogrel prescribing.Materials & methods: We retrospectively analyzed data for 866 patients in which CYP2C19-clopidogrel CDS was deployed at a single healthcare system during 2015-2023.Results: Analyses included 2,288 alerts. CDS acceptance rates increased from 24% in 2015 to 63% in 2023 (p < 0.05). Adjusted analyses also showed higher acceptance rates when clopidogrel had been ordered for a percutaneous intervention (OR: 28.7, p < 0.001) and when cardiologists responded to alerts (OR: 2.11, p = 0.001).Conclusion: CDS for CYP2C19-clopidogrel was effective in reducing potential drug-gene interactions. Its influence varied by clinician specialty and medication indications.

[Box: see text].

Clinical and cost-effectiveness of clopidogrel resistance genotype testing after ischaemic stroke or transient ischaemic attack: a systematic review and economic model.

Background: Stroke or transient ischaemic attack patients are at increased risk of secondary vascular events. Antiplatelet medications, most commonly clopidogrel, are prescribed to reduce this risk. Factors including CYP2C19 genetic variants can hinder clopidogrel metabolism. Laboratory-based or point-of-care tests can detect these variants, enabling targeted treatment. Objective: To assess the effectiveness of genetic testing to identify clopidogrel resistance in people with ischaemic stroke or transient ischaemic attack. Specific objectives: Do people tested for clopidogrel resistance, and treated accordingly, have a reduced risk of secondary vascular events? Do people with loss-of-function alleles associated with clopidogrel resistance have a reduced risk of secondary vascular events if treated with alternative interventions compared to clopidogrel? Do people with loss-of-function alleles associated with clopidogrel resistance have an increased risk of secondary vascular events when treated with clopidogrel? What is the accuracy of point-of-care tests for detecting variants associated with clopidogrel resistance? What is the technical performance and cost of CYP2C19 genetic tests? Is genetic testing for clopidogrel resistance cost-effective compared with no testing? Design: Systematic review and economic model. Results: Objective 1: Two studies assessed secondary vascular events in patients tested for loss-of-function alleles and treated accordingly. They found a reduced risk, but confidence intervals were wide (hazard ratio 0.50, 95% confidence interval 0.09 to 2.74 and hazard ratio 0.53, 95% confidence interval 0.24 to 1.18). Objective 2: Seven randomised controlled trials compared clopidogrel with alternative treatment in people with genetic variants. Ticagrelor was associated with a lower risk of secondary vascular events than clopidogrel (summary hazard ratio 0.76, 95% confidence interval 0.65 to 0.90; two studies). Objective 3: Twenty-five studies compared outcomes in people with and without genetic variants treated with clopidogrel. People with genetic variants were at an increased risk of secondary vascular events (hazard ratio 1.72, 95% confidence interval 1.43 to 2.08; 18 studies). There was no difference in bleeding risk (hazard ratio 0.98, 95% confidence interval 0.68 to 1.40; five studies). Objective 4: Eleven studies evaluated Genomadix Cube accuracy; no studies evaluated Genedrive. Summary sensitivity and specificity against laboratory reference standards were both 100% (95% confidence interval 94% to 100% and 99% to 100%). Objective 5: Seventeen studies evaluated technical performance of point-of-care tests. Test failure rate ranged from 0.4% to 19% for Genomadix Cube. A survey of 8/10 genomic laboratory hubs revealed variation in preferred technologies for testing, and cost per test ranging from £15 to £250. Most laboratories expected test failure rate to be < 1%. Additional resources could enhance testing capacity and expedite turnaround times. Objective 6: Laboratory and point-of-care CYP2C19 testing strategies were cost-saving and increase quality-adjusted life-years compared with no testing. Both strategies gave similar costs, quality-adjusted life-years and expected net monetary benefit. Conclusions: Our results suggest that CYP2C19 testing followed by tailored treatment is likely to be effective and cost-effective in both populations. Future work: Accuracy and technical performance of Genedrive. Test failure rate of Genomadix Cube in a National Health Service setting. Value of testing additional loss-of-function alleles. Appropriateness of treatment dichotomy based on loss-of-function alleles. Limitations: Lack of data on Genedrive. No randomised 'test-and-treat' studies of dipyramidole plus aspirin. Study registration: This study is registered as PROSPERO CRD42022357661. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Evidence Synthesis programme (NIHR award ref: NIHR135620) and is published in full in Health Technology Assessment; Vol. 28, No. 57. See the NIHR Funding and Awards website for further award information.

The most common type of stroke occurs when the supply of blood to the brain is cut off. Symptoms of stroke happen suddenly and vary depending on which part of the brain is affected. They usually include problems with movement, speech, vision and the face drooping on one side. A 'transient ischaemic attack' is a milder related condition. There are around 100,000 strokes and 60,000 transient ischaemic attacks every year in the UK. People who have a stroke or transient ischaemic attack are at greater risk of having another stroke. To reduce the chances of this happening, doctors will often prescribe medication. The most common medication used is called 'clopidogrel'. However, clopidogrel does not work for everyone. One reason for this is having specific variations of a gene called the CYP2C19 gene. Around one in three people in the UK have this variation. We wanted to know whether introducing genetic testing to identify variations in the CYP2C19 gene for people who have had a stroke or transient ischaemic attack can help doctors prescribe a treatment that will work for them, reducing the risk of having another stroke. We also wanted to know if doing this test would be a good use of NHS money. Doing a genetic test to identify variations in the CYP2C19 gene, and prescribing an alternative medication for people with these variations, may reduce the chances of having a new stroke. It is likely that a genetic test for variations of the CYP2C19 gene would represent value for money for the NHS.

Neutrophil count as a risk factor for cardiovascular diseases: how can we manage it?

Neutrophils activation plays a pivotal role in the pathogenesis of atherosclerotic plaque formation, progression and rupture. An association between the leukocyte count and the risk of developing myocardial infarction has been well known for many years; however, only recently did Mendelian randomization studies show that a high neutrophil count is a causal risk factor for atherosclerotic cardiovascular disease. On the other hand, experimental studies show that depletion of circulating neutrophils impairs plaque development. Clopidogrel, an antiplatelet agent, is widely used in combination with aspirin to reduce the incidence of ischemic events in patients treated with coronary stenting. Chronic treatment with this drug reduces inflammatory markers and neutrophil numbers, rarely causing severe leukopenia. The purpose of this review is to present recent evidence showing the link between neutrophil number and the development of cardiovascular diseases and to discuss how the clopidogrel-induced reduction in the neutrophil count may be a beneficial off-target effect of this drug.

Clopidogrel Versus Aspirin as Monotherapy Following Dual Antiplatelet Therapy in Patients With Acute Coronary Syndrome Receiving a Drug-Eluting Stent: A Systematic Literature Review and Meta-Analysis.

OBJECTIVE: This study aimed to evaluate the comparative effectiveness and safety of clopidogrel versus aspirin as monotherapy following adequate dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome (ACS). METHODS: MEDLINE, Embase, and CENTRAL were searched from database inception to September 1, 2023. Randomized controlled trials (RCTs) and observational studies evaluating the effectiveness or safety of clopidogrel versus aspirin as monotherapy following DAPT in patients with ACS who received a drug-eluting stent were included. Random-effects meta-analyses were conducted to compare risks of major adverse cardiovascular events (MACE) and clinically relevant bleeding. RESULTS: Of 6242 abstracts identified, three unique studies were included: one RCT and two retrospective cohort studies. Studies included a total of 7081 post-percutaneous coronary intervention ACS patients, 4260 of whom received aspirin monotherapy and 2821 received clopidogrel monotherapy. Studies included variable proportions of patients with ST-elevation myocardial infarction (STEMI), non-STEMI, and unstable angina. From the meta-analysis, clopidogrel was associated with a 28% reduction in the risk of MACE compared with aspirin (hazard ratio [HR]: 0.72; 95% confidence interval [CI]: 0.54, 0.98), with no significant difference in clinically relevant bleeding (HR: 0.92; 95% CI: 0.68, 1.24). CONCLUSION: Despite the paucity of published evidence on the effectiveness and safety of clopidogrel versus aspirin in patients with ACS post-drug-eluting stent implantation, this meta-analysis suggests that clopidogrel versus aspirin may result in a lower risk of MACE, with a similar risk of major bleeding. The present results are hypothesis-generating and further large RCTs comparing antiplatelet monotherapy options in ACS patients are warranted.

Cost-effectiveness of platelet function testing in dual antiplatelet therapy decision-making after intracranial aneurysm treatment with flow diversion.

Dual antiplatelet therapy (DAPT) use is the standard of practice after flow diversion (FD) for intracranial aneurysms (IAs). Yet, no consensus exists in the literature regarding the optimal regimen. Certain institutions utilize various platelet function testing (PFT) to assess patient responsiveness to DAPT. Clopidogrel is the most commonly prescribed drug during DAPT; however, up to 52% of patients can be non-responders, justifying PFT use. Additionally, prices vary significantly among antiplatelet drugs, often further complicated by insurance restrictions. We aimed to determine the most cost-effective strategy for deciding DAPT regimens for patients after IA treatment. A decision tree with Monte Carlo simulations was performed to simulate patients undergoing various three-month postoperative DAPT regimens. Patients were either universally administered aspirin alongside clopidogrel, ticagrelor, or prasugrel without PFT, or administered one of the former thienopyridine medications based on platelet reactivity unit (PRU) results after clopidogrel. Input data for the model were extracted from the current literature, and the willingness-to-pay threshold (WTP) was defined as $100,000 per QALY as per standard practice in the US. The baseline comparison was with universal clopidogrel DAPT without any PFT. Probabilistic and deterministic sensitivity analyses were performed to evaluate the robustness of the model. Utilizing PFT and switching clopidogrel to prasugrel if resistance is documented was the most cost-effective regimen compared to universal clopidogrel, with a base-case incremental cost-effectiveness ratio (ICER) of $-35,255 (cost $2,336.67, effectiveness 0.85). Performing PFT and switching clopidogrel to ticagrelor (ICER $-4,671; cost $2,995.06, effectiveness 0.84), universal prasugrel (ICER $5,553; cost $3,097.30, effectiveness 0.84), or universal ticagrelor (ICER $75,969; cost $3,801.36, effectiveness 0.84) were all more cost-effective than treating patients with universal clopidogrel (cost $3,041.77, effectiveness 0.83). These conclusions remain robust in probabilistic and deterministic sensitivity analyses. The most cost-effective strategy guiding DAPT after FD for IAs is to perform PFTs and switch clopidogrel to prasugrel if resistance is documented, alongside aspirin. The cost of PFT is strongly justified and recommended when deciding patient-specific DAPT regimens.