Aspirin Resistance In Patients Research Articles

Associiattiion of Cycllooxygenase 1 ((COX1)) Pollymorphiism att SNP RS1330344 wiitth Aspiiriin Resiisttance iin Pakiisttanii Pattiientts Of Ischemiic Heartt Diisease

Objective: To find an association between a single nucleotide polymorphism (SNP) rs1330344 in cyclooxygenase-1 gene with Aspirin resistance in patients with cardiovascular disease in the Pakistani population. Study Design: Cross-sectional study Place and Duration: Pharmacology Department, National University of Medical Sciences, Pakistan, in collaboration with the National Institute of Heart Diseases and Institute of Biomedical and Genetic Engineering Islamabad, Pakistan, from Oct 2018 to Dec 2021. Methodology: The Study was conducted on 384 patients (272 males and 112 females) with ischemic heart disease. Patients on Aspirin for at least seven days were selected. Platelet aggregation was performed using a Light Transmission Aggregatometer and arachidonic acid as an agonist. DNA extraction was done using the kit method (Invitrogen, Thermofisher). Then, Polymerase Chain Reaction, Restriction Fragment Length Polymorphism, and gel electrophoresis were used to identify SNP rs1330344. Results: In this study, 14.0% (n=54) and 86.0% (n=330) of ischemic heart disease patients were resistant to Aspirin and Aspirin, respectively. The genotyping of Cyclooxygenase 1, SNP rs1330344 showed 24.41% (n=94),17.56% (n=67), and 57.98% (n=223) patients had wild type allele (CC), homozygous (TT) and heterozygous (CT) genotype respectively. Gel electrophoresis results for allelic identification were correlated with the anti-platelet efficacy of Aspirin among ischemic heart disease patients. No association was found between a polymorphic form in SNP and the development of aspirin resistance. Conclusion: Aspirin resistance is not associated with any specific polymorphic form of Cyclooxygenase-1 at SNP rs1330344 in the Pakistani population.

Aspirin resistance in patients with ventricular assist devices-A follow-up study.

Despite combined anticoagulation therapy consisting of a vitamin K antagonist and an antiplatelet agent, thromboembolic complications often occur in patients with a left ventricular assist device (LVAD). In addition, bleeding events are also common. Resistance to antiplatelet drugs is a well-known phenomenon; however, the utilization of laboratory chemistry testing for the presence of such resistance, and then switching therapy, is controversial. We tested 132 patients with LVAD (HeartWare n = 57, HeartMate II n = 22, HeartMate 3 n = 53) on acetylsalicylic acid (ASA) therapy for resistance and followed them for a maximum of 7 years regarding pump thrombosis. Light transmission aggregometry (LTA) and impedance aggregometry (IPA) were performed for testing platelet function. We could show that patients with ASA resistance displayed an increased risk of pump thrombosis, regardless of the test used (LTA: OR = 6.20, CI [1.86-20.64], p = 0.003; IPA: OR = 12.14, CI [3.00-49.07], p < 0.001). In patients with a HeartMate 3, we could not detect any pump thrombosis associated with aspirin resistance. Furthermore, there was no significant difference in bleeding events between patients with ASA resistance and ASA responders. Laboratory testing of ASA resistance seems to be a good tool to detect an increased risk of pump thrombosis, at least for patients with a HeartWare or HeartMate II. The extent to which these thromboses can be prevented with a change of medication has to be investigated in further studies. No pump thrombosis was detected in patients with a HeartMate 3, and the question should be asked as to what constellation of underlying and concomitant diseases must be present to justify ASA therapy for these patients.

Potential Aspirin Resistance in Patients with Obstructive Sleep Apnea Syndrome

Potential Aspirin Resistance in Patients with Obstructive Sleep Apnea Syndrome

Coagulation status and determinants of possible aspirin resistance in patients with essential thrombocythemia.

The currently recommended aspirin regimen appears inadequate for thromboprophylaxis in essential thrombocythemia (ET). This study aimed not only to evaluate the curative effect of aspirin but also to explore the coagulation status and determinants of aspirin resistance (AR) of ET patients. A total of 80 ET patients who underwent coagulation tests, thromboelastography (TEG), and next-generation sequencing (NGS) were involved in the study. Patients were divided into the aspirin sensitivity (AS) group and AR group according to the arachidonic acid inhibition rate. Their clinical features and coagulation function were analyzed. The incidence of AR was 53.75% (43/80) in 80 ET patients. Fbg was significantly higher in coagulation tests in AR patients compared with AS patients (P < 0.05), while the differences in other variables (D-D, PT, PTA, INR, APTT, TT, FDP, and AT-III) were not statistically significant (P > 0.05). Compared with AS patients, the K values, α angles, MA values, and CI values of TEG in AR patients were statistically smaller (P < 0.05), but there was no significant difference in R value between them (P > 0.05). Univariate and multivariate logistic regression analysis showed that age, irregular use of aspirin, smoking, dyslipidemia, and hypertension increased the risk of AR (P < 0.05). In the routine NGS, the driver gene and non-driver gene had no effect on AR in ET patients. Compared with AS patients, AR patients have enhanced platelet aggregation function, are in a relatively hypercoagulable state, and haveelevated fibrinogen function/levels, all of which cause a worse coagulation status. ET patients with increasing age, irregular use of aspirin, smoking, dyslipidemia, and hypertension are possibly at higher risk of AR. The routine NGS may not be helpful for the prediction of AR, therefore we recommend adding relevant drug-resistance genes to NGS.

Генетические механизмы аспиринорезистентности у пациентов с атеротромботическим вариантом ишемического инсульта

The purpose — to study the association of rs2317676 polymorphic variants of the GPIIIa gene with the development of aspirin resistance in patients with atherothrombotic variant of ischemic stroke. Material and methods. The article presents data of 100 patients with acute ischemic stroke and 100 people from the control group. All the patients received aspirin at a dose of 300 mg per day during the first day of the disease and 100 or 125 mg per day thereafter. The control group received aspirin as a primary prophylaxis for cardiovascular diseases. The study measured platelet aggregation on day 5–7 of taking the drug. The rs2317676 polymorphism of the GPIIIa gene was considered as genetic marker. Results. The frequency of A/G polymorphism rs2317676 of the GPIIIa gene was lower among individuals with low platelet aggregation compared to individuals with high platelet aggregation (p = 0.023; OR = 0.33; 95% CI: 0.13–0.89). Conclusion. Carriage of the A/G genotype rs2317676 polymorphism of the GPIIIa gene influences an increase in platelet aggregation and the development of aspirin resistance.

Glycemic Control and Aspirin Resistance in Patients Taking Low-Dose Aspirin for Pre-eclampsia Prevention.

To assess the association between aspirin and glycemic control in diabetic, pregnant patients, and the risk for aspirin resistance in those with poor glycemic control across gestation taking low-dose aspirin (LDA) for pre-eclampsia (PEC) prevention. We performed a secondary analysis of samples collected during the Maternal-Fetal Medicine Units trial of LDA for PEC prevention. A subset of insulin-controlled diabetic patient samples on placebo or 60 mg aspirin daily were evaluated. Glycosylated hemoglobin was measured at randomization, mid-second trimester, and third trimester time points. Thromboxane B2 (TXB2) measurements were previously assessed as part of the original study. Primary outcome was the effect of LDA on glycosylated hemoglobin levels compared with placebo across gestation. Levels of glycosylated hemoglobin increased across gestation in the placebo group (2,067.7 [interquartile range, IQR: 1,624.6-2,713.5 µg/mL] vs. 2,461.9 [1,767.0-3,209.9 µg/mL] vs. 3,244.3 [2,691.5-4,187.0 µg/mL]; p < 0.01) compared with no difference in levels of glycosylated hemoglobin across gestation in the LDA group (2,186.4 [IQR: 1,462.3-3,097.7 µg/mL] vs. 2,337.1 [1,327.7-5,932.6 µg/mL] vs. 2,532.9 [1,804.9-5,511.8 µg/mL]; p = 0.78). Higher levels of glycosylated hemoglobin were associated with increased TXB2 levels prior to randomization (r = 0.67, p < 0.05). Incomplete TXB2 was higher in pregnancies with increasing levels of glycosylated hemoglobin compared with those with decreasing levels of glycosylated hemoglobin across gestation (69.2 vs. 18.1%, p = 0.02). LDA exposure may be beneficial to glycemic control in this patient population. Additionally, poor glycemic control is associated with a higher level of TXB2 in diabetic pregnant patients on LDA. Higher doses of aspirin may be required in these patients to prevent development of PEC. · Low-dose aspirin may improve glycemic control.. · Poor glycemic control increases risk for aspirin resistance.. · Higher doses of aspirin may be required for pre-eclampsia prevention..

Impact of Calcium Channel Blockers on Aspirin Reactivity in Patients with Coronary Artery Disease.

Calcium channel blockers (CCBs) do not reduce the risk of initial or recurrent myocardial infarction (MI) in patients diagnosed with stable coronary artery disease (CAD). The aim of this current study was to evaluate the association between CCBs and aspirin resistance in patients with CAD. Patients with stable CAD who were regularly taking aspirin (75-100 mg qd) for at least 1 month prior to enrollment in the study were included. The VerifyNow system was used for platelet function testing with high on-aspirin platelet reactivity (HAPR) defined as aspirin reaction units (ARU) >550. We compared patients treated with CCBs versus control group. Five hundred three patients with CAD were included in this study, and 88 were treated with CCBs. Mean age (67.9±9.7 in the CCB group vs. 66.5±11.4 in the control group), gender (77.3 male vs. 82.9%), rates of diabetes mellitus (34.7 vs. 36.9%), rates of CKD (23.5 vs. 23.5%), dyslipidemia (85.1 vs. 85.3%), and statin therapy (89.5 vs. 90.7%) were similar. The mean ARU was 465.4±70.0 for patients treated with CCBs versus 445.2±60.0 in controls (p=0.006). Similarly, 15.9% of CCB patients demonstrated HAPR compared to 7.0% (p=0.006). The administration of CCBs was independently associated with HAPR in a multivariate analysis (OR 1.72, 95% CI: 1.04-8.91, p=0.047) as well as in propensity score matched analysis (OR 1.56; CI: 1.22-1.93; p<0.001). Usage of CCBs is positively correlated with aspirin resistance. These findings may suggest an adverse pharmacologic effect of CCBs among patients with stable CAD treated with aspirin.

Effect of acupuncture for regulating spleen and stomach on aspirin resistance in patients with type 2 diabetes mellitus: a randomized controlled trial

To observe the effect of acupuncture for regulating spleen and stomach on aspirin resistance in patients with type 2 diabetes mellitus (T2DM) and explore the effect mechanism. A total of 68 T2DM patients complicated with aspirin resistance were randomized into an observation group and a control group, 34 cases in each one. On the base of the conventional treatment for diabetes, aspirin enteric-coated tablets were prescribed for oral administration, 100 mg each time, once daily in the control group. In the observation group, on the basis of the treatment as the control group, acupuncture was used for regulating spleen and stomach at Zhongwan (CV 12), Zusanli (ST 36), Yinlingquan (SP 9), Hegu (LI 4), etc., once daily. The treatment for 1 week was as one course and 4 courses of treatment were required totally in two groups. Before and After treatment, the indexes of platelet function (platelet aggregation rate [PAG] and salicylic acid concentration), the indexes of vascular endothelial function (6-keone prostaglandin F1α[6-keto-PGF1α], thromin B2 [TXB2] and cyclooxysynthase-2 [COX-2]), blood glucose (fasting plasma glucose [FPG], 2 h plasma glucose [2h PG] and glycosylated hemoglobin [HbA1c]), insulin resistance index (HOMA-IR), blood lipid indexes (total cholesterol [TC], triacylglycerol [TG], high-density lipoprotein cholesterol [HDL-C] and low-density lipoprotein cholesterol [LDL-C]) and the total score of TCM symptoms were observed in the patients of two groups. Clinical therapeutic effect and safety was compared in the patients between the two groups after treatment and the recurrence rate of cardiocerebrovascular events was followed up 6 months after treatment. After treatment, PAG, salicylic acid concentration, TXB2, COX-2, FPG, 2h PG, HbA1c, HOMA-IR, LDL-C, TC, TG and the total scores of TCM symptoms were all reduced as compared with those before treatment in the two groups (P<0.01, P<0.05), and 6-keto-PGF1αand HDL-C were increased as compared with those before treatment in the two groups (P<0.01, P<0.05). In comparison with the control group, the aforementioned indexes in the observation group were all improved significantly (P<0.01). The total effective rate was 91.2% (31/34) in the observation group, higher than 70.6% (24/34) in the control group (P<0.05). In follow up visit, the recurrence rate of cardiocerebrovascular events was 14.7% (5/34) in the observation group, lower than 29.4% (10/34) in the control group (P<0.05). The therapies were safe and had no obvious adverse reactions in both two groups. Acupuncture for regulating spleen and stomach combined with aspirin enteric-coated tablets relieve insulin resistance and reduces blood glucose and lipid as well as the recurrence rate of cardiocerebrovascular events in the patients with T2DM, which is probably related to the regulation of insulin resistance and the improvement of vascular endothelial function. This combined therapy achieves the better effect on aspirin resistance as compared with simple aspirin enteric-coated tablets.

Генетические аспекты аспиринорезистентности у пациентов с цереброваскулярной патологией

Введение. Цереброваскулярные заболевания (ЦВЗ) и нарушения мозгового кровообращения (НМК) остаются одной из основных причин смерти во всем мире. Доказана генетическая составляющая возникновения НМК, генетические полиморфизмы могут изменять ответ на фармакологические агенты. Ацетилсалициловая кислота (АСК) — «золотой стандарт» антиагрегантного лечения ЦВЗ. С начала XXI века в мировой науке накопились факты о недостаточном эффекте АСК, в связи с чем возник термин аспиринорезистентность. Цель исследования: оценка вклада гемореологических и генетических факторов в возникновение феномена аспиринорезистентности у пациентов с ЦВЗ. Материалы и методы. В настоящее проспективное рандомизированное контролируемое наблюдательное исследование были включены 186 пациентов с ЦВЗ в возрасте 45–75 лет. Все пациенты получали 75 мг АСК ежедневно. Наряду с комплексным клиническим обследованием, оценкой когнитивного статуса и приверженности к лечению, проводилась лабораторная оценка функции тромбоцитов, развернутый биохимический анализ крови, идентификация полиморфизмов A842G гена циклооксигеназы 1-го типа (ЦОГ-1) (rs 10306114), С50Т ЦОГ-1 (rs3842787) и А1676G ЦОГ-1 (rs1330344). Статистическая обработка выполнена с использованием программ IBM SPSS Statistics. Результаты. Выявлена положительная взаимосвязь между уровнем агрегации тромбоцитов (АТ) с аденозиндифосфатом (АТ-АДФ) и адреналином и (АТ-адр) и пробой АСК in vitro (r = 0,722 и r = 0,689; р &lt; 0,001). Обнаружена отрицательная взаимосвязь между АТ-АДФ и баллом по Монреальской шкале оценки когнитивных функций (англ. Montreal Cognitive Assessment, MoCA) и приверженностью к лечению (r = –0,845; p = 0,001). На основании анализа АТ все обследованные были подразделены на АСК-нечувствительных (группа 1, n = 100) и АСК-чувствительных (группа 2, n = 86). В группе АСК-нечувствительных наблюдалось больше пациентов, несущих хотя бы один аллель G полиморфизма гена ЦОГ-1 rs1330344 по сравнению с пациентами в группе ACK-чувствительных (60,4% против 47,7%; p &lt; 0,01). Наличие rs1330344 часто ассоциировано с сахарным диабетом 2-го типа (отношение шансов = 3,749; 95% доверительный интервал = 1,937–7,254; p = 0,001). Полиморфизм ЦОГ-1 C50T (rs3842787) по данным логистической регрессии связан с АТ-Адр (r = 0,845; р &lt; 0,001). Заключение. Среди причин аспиринорезистентности у пациентов с ЦВЗ следует учитывать генетические аспекты. Background. Cerebrovascular disease (CVD) and stroke remain one of the leading causes of death worldwide. The genetic component of stroke has been proven; genetic polymorphisms can alter the response to pharmacological agents. Acetylsalicylic acid (ASA) is the “gold standard” for antiplatelet treatment of CVD. Since the beginning of the XXI century, the world science has accumulated facts about the insufficient effect of ASA, so the term aspirin resistance appeared. Objectives: to assess hemorheological and genetic factors to the occurrence of the phenomenon of aspirin resistance in patients with CVD. Patients/Methods. This prospective randomized controlled observational study included 186 patients with CVD, aged 45–75 years. All patients received 75 mg ASA daily. Clinical examination, assessment of cognitive status and compliance to treatment, a laboratory assessment of platelet function, a detailed biochemical blood test, identifi cation of A842G polymorphisms of type 1 cyclooxygenase (COX-1) gene (rs 10306114), C50T COX-1 (rs3842787) and A1676G COX-1 (rs3842787) and A1676G COX-1 (rs1330344) were performed. Statistics was carried out using the IBM SPSS Statistics software. Results. The positive correlation was found between platelet aggregation (РА) with adenosine diphosphate (РА-ADP) and adrenaline (РА-Аdr) and an in vitro test with ASA (r = 0.722 and r = 0.689; p &lt; 0.001). A negative correlation was found between РА-ADP and the Montreal Cognitive Assessment (MoCA) score for compliance to treatment (r = –0,845; p = 0,001). Based on the analysis of PA, all examined patients were divided into ASA-insensitive (group 1, n = 100) and ASA-sensitive (group 2, n = 86). In the ASA-insensitive group, there were more patients carrying at least one G allele of the COX-1 gene rs1330344 polymorphism compared with patients in the ACK-sensitive group (60.4% versus 47.7%; p &lt; 0.01). The presence of rs1330344 is often associated with type 2 diabetes mellitus (OR = 3.749; 95% СI = 1.937–7.254; p = 0.001). C50T polymorphism of COX-1 (rs3842787) according to logistic regression is associated with AT-Adr (r = 0.845; p &lt; 0.001). Conclusions. Genetic aspects should be considered among the causes of aspirin resistance in patients with CVD.

Monitoring of Aspirin Therapy in Patients with Cerebrovascular Pathology

Aim. Evaluation of various methods for determining the effectiveness of aspirin therapy and aspirin resistance in patients with cerebrovascular disease (CVD) depending on the presence of type 2 diabetes mellitus (T2DM).Materials and methods. The prospective study included 78 patients with various manifestations of CVD. All patients received acetylsalicylic acid (ASA) 75 mg daily. Along with a comprehensive clinical examination, a laboratory assessment of platelet function with the usage of Born method with aggregometer, a detailed biochemical blood test (including the determination of the small subunit of low density lipoprotein [s-LDL]), as well as therapeutic drug monitoring of salicylates were performed on a gas chromatograph-mass spectrometer.Results. In 53% of cases, the absence or insufficiency of the effect of ASA on platelet aggregation was noted. Two subgroups were separately identified: with T2DM; (n=40) and without T2DM (n=38). Insufficient effect of the drug on platelet aggregation characteristics were observed in 65% of patients with T2DM and in 38% without T2DM. The differences were revealed between the groups in triglycerides, s-LDL, glycemic and glycated hemoglobin (p &lt;0.05). In the group of patients with T2DM, the median ASA concentration was 0.01 [0; 0.32] μg/ml, and salicylic acid (SA)– 0.20 [0; 0.39] μg/ml, while in patients without T2DM higher values were noted: ASA 0.29 [0.15; 0.55] μg/ml, SA – 0.33 [0.05; 0.73] μg/ml. A decrease in the concentration of ASA was associated with an increase in the level of ADP-induced platelet aggregation. There was an increase in the levels of ADPand adrenaline-induced platelet aggregation with a decrease in the concentration of ASA (p=0.004) and SA (p=0.006). Therapeutic drug monitoring revealed a more significant decrease in ASA level in T2DM than in the comparison group (p=0.025).Conclusion. It is advisable to monitor aspirin therapy both with the assessment of platelet aggregation and with therapeutic drug monitoring. The relationship between the level of ASA and SA in the blood plasma and the functional activity of platelets was confirmed. The presence of T2DM is associated with a decrease in the concentration of ASA and aspirin resistance detected in therapeutic drug monitoring.

Aspirin Resistance in Patients with Chronic Coronary Syndrome

This review summarizes aspirin features, actions and resistance in patients with chronic coronary syndrome. As well, it describes mechanism of the aspirin action and possible ways and causality of the aspirin resistance. In addition, it shows how to assess the efficacy of the aspirin therapy in patients with chronic coronary syndrome.

Chronic Application of Low-Dose Aspirin Affects Multiple Parameters of Three Blood Cellular Types and Antithrombin Activity: A 1:1:1 Propensity Score Matching Analysis

The mechanisms of aspirin antithrombotic actions have not been fully elucidated. We re-analyzed the data from the project Aspirin Resistance in Patients with Ischemic Atherothrombotic Diseases from April 2008 to June 2010. A total of 530 subjects were classified into 3 groups, including 40 patients without aspirin use, 24 patients taking 25-50 mg/d aspirin, and 466 patients taking 75-100 mg/d aspirin over 1 month. By 1:1:1 propensity score matching adjusting 15 primary clinical covariates, 51 patients (n = 17 per group) comprised the final sample. Hemostasis-related parameters and high platelet reactivity as measured by arachidonic acid-induced and adenosine diphosphate-induced light transmission aggregometry were compared in the 3 groups. A dose-dependent relationship was observed between aspirin and decreased high platelet reactivity incidence (PAA < 0.001, PADP < 0.01, respectively), decreased monocyte ratio (P = 0.052), increased antithrombin activity (P < 0.001), and increased platelet distribution width (P < 0.05). Aspirin at 25-50 mg/d is related to the lowest red blood cell (RBC) count, whereas 75-100 mg/d aspirin showed the highest RBC count among the 3 groups (4.52 ± 0.35 × 1012/L vs. 4.35 ± 0.57 × 1012/L vs. 4.80 ± 0.59 × 1012/L, P = 0.046). Our finding demonstrated that aspirin exerts its antithrombotic effects at least by antiplatelet function, enhancing antithrombin activity and suppressing monocytes in vivo. In addition, 3 blood cell types, namely RBCs, monocytes, and platelets, are involved in the aspirin antithrombotic mechanism. The cellular response to aspirin partially enhances the antithrombotic effects while partially inhibiting the effects.

A Narrative Review of Aspirin Resistance in VTE Prophylaxis for Orthopaedic Surgery.

Total hip arthroplasties (THA) and total knee arthroplasties (TKA) confer one of the highest risks for developing venous thromboembolism (VTE) and pharmacological prophylaxis is imperative to help mitigate the risks. Aspirin is the most cost-effective medication for VTE prophylaxis, and its use post-THA/TKA has grown in popularity. Aspirin resistance is categorised as clinical or laboratory resistance with obesity, advancing age, diabetes mellitus, dyslipidaemia and inflammatory diseases identified as risk factors for aspirin resistance. Treatment failure due to aspirin resistance has been reported in cardiovascular and cerebrovascular disease leading to increased rates of mortality and re-embolisation. However, aspirin resistance in patients undergoing a THA/TKA has not been described, nor has there been investigation into the incidence rates or clinical outcomes. The aim of this narrative review is to appraise the concept of aspirin resistance in the context of aspirin use for VTE prophylaxis after THA/TKA surgeries. This is important to investigate as the risk factors for aspirin resistance, including obesity, advancing age, diabetes mellitus, dyslipidaemia and inflammatory diseases, are also risk factors for THA/TKA and risk factors for VTE. The presence of aspirin resistance in patients undergoing orthopaedic surgery may place patients at greater risk of thrombotic events if aspirin is prescribed for VTE prophylaxis. This could further increase the risk of complications associated with VTE and potential long-term consequences such as post-thrombotic syndrome. Future research is required to explore and quantify the rates of aspirin resistance and the clinical outcomes in orthopaedic patients; especially in those patients with these overlapping risk factors for THA/TKA, VTE and aspirin resistance.

Prevalence and Features of Aspirin Resistance in Patients with Coronary Artery Disease

Purpose. To determine the frequency of development of aspirin resistance in patients with coronary heart disease and to identify risk factors for the development of resistance to acetylsalicylic acid (ASA) in patients with coronary heart disease. Material and Methods: 96 patients were enrolled in this study with stable forms of ischemic heart disease who received a standard dose of aspirin 75 mg/day for a long time. Patients were divided into 4 groups according to the prescription of ASA. Group 1 consisted of patients who did not receive aspirin, the second group consisted of patients taking aspirin up to 1 year, the third group consisted of patients taking aspirin from 1 year to 5 years, and the fourth group included patients taking aspirin for more than 5 years. An addition, according to the results of determining aspirin resistance, the patients were divided into 2 groups. Platelet aggregation was measured using a laser analyzer: adenosine diphosphate (ADP) with 1.0 and 5.0 μmol was used. Resistance criterion: ADP ≥72% at 5.0 μmol. Results: 17.7% of patients who took aspirin in a standard dose of 75 mg/day were resistant to aspirin, and a third of them took aspirin for more than 5 years. According to the results of a study of platelet aggregation activity, the average degree of platelet aggregation with 5.0 μmol of ADP was 82.4% in patients with no reaction to aspirin. An inadequate response to aspirin was reliably often observed in women and the elderly (58.8% and 70.5%). When analyzing the results of routine laboratory studies in patients with aspirin resistance, there was a tendency to higher levels of cholesterol and glucose (p˂0.05). Possible risk factors for the development of ASA resistance are hypercholesterolemia and hyperglycemia, since aspirin resistance was more common in patients with diabetes (13 out of 17) and obesity (11 out of 17).Conclusion: High rates of ADP-induced platelet aggregation were obtained in ¼ patients with coronary heart disease. A

1156: Glycemic control and aspirin resistance in patients taking low-dose aspirin for preeclampsia prevention

1156: Glycemic control and aspirin resistance in patients taking low-dose aspirin for preeclampsia prevention

Determinants of aspirin resistance in patients with type 2 diabetes

BackgroundCardiovascular disease is a leading cause of mortality among patients with type 2 diabetes mellitus (T2DM). Numerous patients with T2DM show resistance to aspirin treatment, which may explain the higher rate of major adverse cardiovascular events observed compared with non-diabetes patients, and it has recently been shown that aspirin resistance is mainly related to accelerated platelet turnover with persistent high platelet reactivity (HPR) 24h after last aspirin intake. The mechanism behind HPR is unknown. The aim of this study was to investigate the precise rate and mechanisms associated with HPR in a population of T2DM patients treated with aspirin. MethodsIncluded were 116 consecutive stable T2DM patients who had attended our hospital for their yearly check-up. HPR was assessed 24h after aspirin intake using light transmission aggregometry (LTA) with arachidonic acid (AA) and serum thromboxane B2 (TXB2) measurement. Its relationship with diabetes status, insulin resistance, inflammatory markers and coronary artery disease (CAD) severity, using calcium scores, were investigated. ResultsUsing LTA, HPR was found in 27 (23%) patients. There was no significant difference in mean age, gender ratio or cardiovascular risk factors in patients with or without HPR. HPR was significantly related to duration of diabetes and higher fasting glucose levels (but not consistently with HbA1c), and strongly related to all markers of insulin resistance, especially waist circumference, HOMA-IR, QUICKI and leptin. There was no association between HPR and thrombopoietin or inflammatory markers (IL-6, IL-10, indoleamine 2,3-dioxygenase activity, TNF-α, C-reactive protein), whereas HPR was associated with more severe CAD. Similar results were found with TXB2. ConclusionOur results reveal that ‘aspirin resistance’ is frequently found in T2DM, and is strongly related to insulin resistance and severity of CAD, but weakly related to HbA1c and not at all to inflammatory parameters. This may help to identify those T2DM patients who might benefit from alternative antiplatelet treatments such as twice-daily aspirin and thienopyridines.

Assessment of the relationship between platelet reactivity, vascular risk factors and gender in cerebral ischaemia patients.

Excessive activation and platelet aggregation play important roles in the aetiopathogenesis of cerebral ischaemia. The aim of this study was to assess the relationship between platelet reactivity, gender and vascular risk factors in cerebral ischaemia patients. The research is useful because we found high risk groups of inefficient aspirin treatment in cerebral ischaemia patients. The study involved 101 patients, including 69 patients with ischaemic stroke and 32 patients with transient ischaemic attack. The assessment of platelet reactivity was made within 24 hours of the disease onset using two aggregometric methods: impedance and optical. Resistance to acetylsalicylic acid among people with cerebral ischaemia was estimated at 30.69% using impedance aggregometry and 9.2% using optical aggregometry. There were no differences in platelet reactivity or ASA resistance between the groups of patients with stroke and TIA in either method. In the whole group of patients (p = 0.04), and in the group of patients with stroke (p = 0.0143), higher reactivity of platelets was observed by impedance aggregometry in men than in women. In the whole group of patients (p = 0.0229), and in the subgroup with stroke (p = 0.0123), it was shown that aspirin resistance is significantly more common in the subgroup of men than in women. In patients suffering from nicotine addiction, significantly higher platelet reactivity was found in the whole group of patients (p = 0.004), as well as in the subgroup of patients with stroke (p = 0.0135). There are no differences between platelet reactivity and the incidence of aspirin resistance in patients with stroke and TIA. Male gender and smoking are associated with greater reactivity of platelets and more frequent occurrence of acetylsalicylic acid resistance in patients with cerebral ischaemia. Dual antiplatelet therapy or clopidogrel treatment should be considered in smoking males with cerebral ischaemia due to the high risk of aspirin inefficiency.

Unexpected Low Expression of Platelet Fibrinogen Receptor in Patients with Chronic Myeloproliferative Neoplasms: How Does It Change with Aspirin?

INTRODUCTIONPatients affected by Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are considered at high risk of thrombo-haemorrhagic events, but the role of the platelet count in the assessment of the risk of vascular events is still controversial. A tight correlation was found between the platelet count and plasma sCD40L, which appears to be required for thrombus formation in vivo. However sCD40L is increased both in MPNs and reactive thrombocytosis. Intravascular aggregates of platelets and leukocytes, mediated by P-selectin and CD11b on the former and the latter, respectively, have been observed.Both of this processes should imply a perpetual - and measurable - platelet activation. Several studies on platelet function have been already proposed, nevertheless the mechanisms through which platelets are able to trigger vascular events, are not yet adequately clarified.A refined method for the determination of platelet activation appears to be the use of platelet PAC-1 antibody, able to identify the expression of the fibrinogen receptor of platelet glycoprotein IIb/IIIa. This expression is indeed unique in the process of platelet activation, and yet rarely analyzed. Moreover, since the platelet fibrinogen receptor exposure seems to be influenced by turbulence in blood flow, we have thought that its evaluation could provide important biological evidences to explain some clinical manifestations, such as microvascular disturbances.METHODSBlood samples from 40 consecutive MPNs patients who never received cytoreductive agents, were obtained. 28/40 patients were receiving a continuative antiplatelet prophylaxis with low dose aspirin (ASA, 75-100 mg) at the time of collection, while 12/40 of them were not on such therapy. Our aim was to verify the expression of platelet fibrinogen receptors (PFRs) in the two different groups of patients compared to healthy volunteers, using whole blood flow cytometry. In each experiment sodium citrate and heparin (positive control of platelet activation) tubes were collected from the same patient. Within 10 minutes from blood sampling, 5 ml of whole blood from each tube was incubated for 20 minutes at room temperature in the dark with saturating concentration of CD61 PerCP, CD62P PE and PAC-1 FITC. Positive control was also incubated with PAC-1 in the presence of Arg-Gly-Asp-Ser (RGDS) in order to test the specific antibody binding. Samples were fixed with paraformaldehyde 1% for 30 minutes at 4°C in the dark and analyzed on a flow cytometer.RESULTSSurprisingly, we have been able to verify a very low PAC-1 binding to platelets in patients with MPNs not receiving cytoreduction nor antiplatelet agents (33%) if compared to that observed in healthy subjects (61%; p<0.0001). The use of aspirin seems conversely to restore the expression of platelet fibrinogen receptor, as PAC-1 binding capacity is comparable to that of healthy volunteers (56%). No difference was found with respect to the JAK2 Val617Phe mutation and its allele burden. Interestingly, by focusing on the group of patients under antiplatelet prophylaxis and with no history of thrombosis, it was found that subjects with persistent microcirculatory disorders show a higher PAC-1 binding capacity if compared to the asymptomatic ones (67% vs 52%, p= 0.04).CONCLUSIONIn untreated MPNs, a large amount of platelets are resting in a conformation that is unable to bind fibrinogen, as demonstrated by the low PAC-1 expression in cytofluorimetry. This lack of activity can be reversed by administering ASA, which is also known for its fibrinolytic and hypoprothrombinemic effects. We hypotesize that the hypercoagulable states observed in these patient could depend on a primarly plasma-driven impairment of fibrin turnover and thrombin generation. Further investigations are going to be promoted by our Group. PAC-1 could be at the same time a good marker of aspirin resistance in patients experiencing microcirculatory disorders. [Display omitted] DisclosuresMartinelli:Janssen: Consultancy; Jazz Pharmaceuticals: Consultancy; Ariad/Incyte: Consultancy; Pfizer: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy; Abbvie: Consultancy; Roche: Consultancy; Novartis: Speakers Bureau.

İskemik inme hastalarında aspirin direnci

İskemik inme hastalarında aspirin direnci

Prevalence of aspirin resistance in patients with type II diabetes: a descriptive-analytical study .

Aspirin resistance is one of the most important factors for arterial thrombotic events in diabetic patients. This study aimed to evaluate aspirin resistance in diabetic patients. In this cross-sectional study, 180patients who received 80mg of aspirin daily for at least 10 days were studied, and their urinary 11-DH-TXB2 was measured. Those with 11-dehydro-thromboxane B2 above 1,500pg/mg creatinine were considered aspirin resistant. Data with significance level of 5% were analyzed in SPSS-16. The mean±SD of patient age was 60.22±9.59 years and 50% (n=90) were male. BMI was normal in 29.4% of the patients (n=53), the others were overweight or obese. Aspirin resistance was observed in 33 (18%) patients. The relationship between aspirin resistance and gender, age, and BMI was not significant (p>0.05). There is a high prevalence of aspirin resistance in diabetic patients and given that such patients are at risk of arterial thrombotic events, evaluation of aspirin resistance is suggested for those at a high risk of cardiovascular events or recurring events despite the use of aspirin. .