Urinary 11-Dehydro-Thromboxane B2 and Mortality in Patients With Stable Coronary Artery Disease

Key Mutant Genes and Biological Pathways Involved in Aspirin Resistance in the Residents of the Chinese Plateau Area

INTRODUCTION

Aspirin is used to prevent and treat cardiovascular diseases; however, some patients develop aspirin resistance.

AIM

We aimed to explore the potential molecular mechanisms underlying aspirin resistance in people living in the Chinese plateau area.

METHODS

In total, 91 participants receiving aspirin treatment from the Qinghai plateau area were divided into the aspirin resistance and aspirin sensitivity groups. Genotyping was performed using the Sequence MASSarray. Differentially mutated genes between the two groups were analyzed using MAfTools. The annotation of differentially mutated genes was conducted based on the Metascape database.

RESULTS AND DISCUSSION

In total, 48 differential SNP and 22 differential InDel mutant genes between the aspirin resistance and aspirin sensitivity groups were screened using Fisher's exact test (P < 0.05). After the χ2 test, a total of 21 SNP mutant genes, including ZFPL1 and TLR3, and 19 InDel mutant genes were found to be differentially expressed between the two groups (P < 0.05). Functional analysis revealed that these differential SNP mutations were mainly enriched in aspirin resistance pathways, such as the Wnt signaling pathway. Furthermore, these genes were related to many diseases, including various aspirin indications.

CONCLUSION

This study identified several genes and pathways that could be involved in arachidonic acid metabolic processes and aspirin resistance progression, which will provide a theoretical understanding of the molecular mechanism of aspirin resistance.

Zhilong Huoxue Tongyu Capsule Ameliorates Platelet Aggregation and Thrombus Induced by Aspirin in Rats by Regulating Lipid Metabolism and MicroRNA Pathway

INTRODUCTION

Zhilong Huoxue Tongyu capsule (ZLHX) is a traditional Chinese medicinal compound preparation, which exhibits obvious therapeutic effects on aspirin resistance (AR). However, the mechanism of ZLHX on AR is rarely reported.

OBJECTIVES

This study aimed to explore the therapeutic effects of AR and the underlying mechanisms of ZLHX on AR rats.

METHODS

An AR model was established through treatment with a high-fat, high-sugar, and highsalt diet for 12 weeks and oral administration of aspirin (27 mg/kg/day) and ibuprofen (36 mg/kg/day) in weeks 9-12. The rats were administrated with ZLHX (225, 450, and 900 mg/kg) from week 12 to week 16. Blood samples were collected after the experiment. Thromboelastography analysis was performed, and the levels of triglyceride (TG), total cholesterol (TC), lowdensity lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were determined. Furthermore, the levels of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1α (6- keto-PGF1α) were determined with commercial ELISA kits. Finally, the gene expressions of microRNA- 126-3p (miRNA-126-3p) and miRNA-34b-3p were detected through a real-time quantitative polymerase chain reaction.

RESULTS

Results demonstrated that ZLHX significantly inhibited platelet aggregation in the AR rats. Moreover, ZLHX markedly decreased the levels of TC, TG, and LDL-C and increased the level of HDL-C. Meanwhile, ELISA results confirmed that ZLHX can elevate the expression levels of TXB2 and 6-keto-PGF1α. Further studies suggested that ZLHX significantly downregulated the expression levels of miRNA-126-3p and miRNA-34b-3p.

CONCLUSION

This study revealed that the therapeutic effect of ZLHX might be related to the regulation of lipid metabolism and the miRNA pathway.

Short-term efficacy and safety of personalized antiplatelet therapy for patients with acute ischaemic stroke or transient ischaemic attack: A randomized clinical trial

AIMS

The aim of this study was to determine whether the testing strategy for clopidogrel and/or aspirin resistance using CYP2C19 genotyping or urinary 11-dhTxB2 testing has an impact on clinical outcomes.

METHODS

A multicentre, randomized, controlled trial was conducted at 14 centres in China from 2019 to 2021. For the intervention group, a specific antiplatelet strategy was assigned based on the CYP2C19 genotype and 11-dhTxB2, a urinary metabolite of aspirin, and the control group received nonguided (ie, standard of care) treatment. 11-dhTXB2 is a thromboxane A2 metabolite that can help quantify the effects of resistance to aspirin in individuals after ingestion. The primary efficacy outcome was new stroke, the secondary efficacy outcome was a poor functional prognosis (a modified Rankin scale score ≥3), and the primary safety outcome was bleeding, all within the 90-day follow-up period.

RESULTS

A total of 2815 patients were screened and 2663 patients were enrolled in the trial, with 1344 subjects assigned to the intervention group and 1319 subjects assigned to the control group. A total of 60.1% were carriers of the CYP2C19 loss-of-function allele (*2, *3) and 8.71% tested positive for urinary 11-dhTxB2- indicating aspirin resistance in the intervention group. The primary outcome was not different between the intervention and control groups (P = .842). A total of 200 patients (14.88%) in the intervention group and 240 patients (18.20%) in the control group had a poor functional prognosis (hazard ratio 0.77, 95% confidence interval [CI] 0.63 to 0.95, P = .012). Bleeding events occurred in 49 patients (3.65%) in the intervention group and 72 patients (5.46%) in the control group (hazard ratio 0.66, 95% CI 0.45 to 0.95, P = .025).

CONCLUSIONS

Personalized antiplatelet therapy based on the CYP2C19 genotype and 11-dhTxB2 levels was associated with favourable neurological function and reduced bleeding risk in acute ischaemic stroke and transient ischaemic attack patients. The results may help support the role of CYP2C19 genotyping and urinary 11-dhTxB2 testing in the provision of precise clinical treatment.

The Effects of Temperature and Humidity Index on Growth Performance, Colon Microbiota, and Serum Metabolome of Ira Rabbits

This study investigates the effects of different THI values on growth performance, intestinal microbes, and serum metabolism in meat rabbits. The results showed that there were significant differences in THI in different location regions of the rabbit house. The high-THI group (HG) could significantly reduce average daily gain and average daily feed intake in Ira rabbits (p < 0.05). The low-THI group (LG) significantly increased the relative abundance of Blautia (p < 0.05). The HG significantly increased the relative abundance of Lachnospiraceae NK4A136 group and reduced bacterial community interaction (p < 0.05). The cytokine-cytokine receptor interactions, nuclear factor kappa B signaling pathway, and toll-like receptor signaling pathway in each rabbit's gut were activated when the THI was 26.14 (p < 0.05). Metabolic pathways such as the phenylalanine, tyrosine, and tryptophan biosynthesis and phenylalanine metabolisms were activated when the THI was 27.25 (p < 0.05). Meanwhile, the TRPV3 and NGF genes that were associated with heat sensitivity were significantly upregulated (p < 0.05). In addition, five metabolites were found to be able to predict THI levels in the environment with an accuracy of 91.7%. In summary, a THI of 26.14 is more suitable for the growth of meat rabbits than a THI of 27.25, providing a reference for the efficient feeding of meat rabbits.

Study the Association of Nucleotide Polymorphisms in Platelet Receptor and Cytochrome P450 Genes with the Development of Resistance to Antiplatelet Drugs in Patients with Coronary Artery Disease

Aim. To study the association of nucleotide polymorphisms in platelet receptor and cytochrome P450 genes with the development of resistance to antiplatelet drugs in CHD patients.

Material and Methods. The study included 243 patients diagnosed with CHD after coronary artery bypass surgery (CABG), including 140 patients in the acetylsalicylic acid (ASA) treatment group and 103 patients in the dual antiplatelet therapy (DAT) group. All patients were tested for platelet aggregation using an optical aggregometer with inducers: 5 mM ADP and 1 mM arachidonic acid (AA). DNA samples were analyzed by allele-specific PCR for the presence of polymorphisms rs2046934, rs1126643, rs5918, rs6065, rs4244285 in the platelet receptor and cytochrome P450 genes.

Results. No statistically significant differences were found during comparison of the prevalence of the studied polymorphisms in the platelet receptor and cytochrome P450 genes between the groups of aspirin-sensitive and aspirin-resistant patients, as well as between the groups of clopidogrelsensitive and clopidogrel-resistant patients. No association between carriage of the minor and major alleles of the polymorphisms studied and the development of antiplatelet drug resistance was found. In the group of patients on ASA therapy, carriers of the C allele of the T1565C (rs5918) ITGB3 polymorphism had a higher rate of AA-induced platelet aggregation compared to carriers of the T allele (18,49±25,92 vs 10,43±17,34, р=0,004).

Conclusion. Polymorphisms of P2RY12 (rs2046934), ITGA2 (rs1126643), ITGB3 (rs5918), GP1BA (rs6065), CYP2C19*2 (rs4244285) genes are not associated with antiplatelet drug resistance in both patients on ASC therapy and on DAT. The presence of minor alleles of the rs2046934, rs1126643, rs6065, rs4244285 polymorphisms are not associated with increased platelet aggregation activity before CABG.However, in the group of patients on ASA therapy C-allele carriers of the rs5918 polymorphism of the ITGB3 gene had a higher rate of AA-induced platelet aggregation compared to T-allele carriers.

Association of Thromboxane Generation With Survival in Aspirin Users and Nonusers

BACKGROUND

Persistent systemic thromboxane generation, predominantly from nonplatelet sources, in aspirin (ASA) users with cardiovascular disease (CVD) is a mortality risk factor.

OBJECTIVES

This study sought to determine the mortality risk associated with systemic thromboxane generation in an unselected population irrespective of ASA use.

METHODS

Stable thromboxane B₂ metabolites (TXB₂-M) were measured by enzyme-linked immunosorbent assay in banked urine from 3,044 participants (mean age 66 ± 9 years, 53.8% women) in the Framingham Heart Study. The association of TXB₂-M to survival over a median observation period of 11.9 years (IQR: 10.6-12.7 years) was determined by multivariable modeling.

RESULTS

In 1,363 (44.8%) participants taking ASA at the index examination, median TXB₂-M were lower than in ASA nonusers (1,147 pg/mg creatinine vs 4,179 pg/mg creatinine; P < 0.0001). TXB₂-M were significantly associated with all-cause and cardiovascular mortality irrespective of ASA use (HR: 1.96 and 2.41, respectively; P < 0.0001 for both) for TXB₂-M in the highest quartile based on ASA use compared with lower quartiles, and remained significant after adjustment for mortality risk factors for similarly aged individuals (HR: 1.49 and 1.82, respectively; P ≤ 0.005 for both). In 2,353 participants without CVD, TXB₂-M were associated with cardiovascular mortality in ASA nonusers (adjusted HR: 3.04; 95% CI: 1.29-7.16) but not in ASA users, while ASA use was associated with all-cause mortality in those with low (adjusted HR: 1.46; 95% CI: 1.14-1.87) but not elevated TXB₂-M.

CONCLUSIONS

Systemic thromboxane generation is an independent risk factor for all-cause and cardiovascular mortality irrespective of ASA use, and its measurement may be useful for therapy modification, particularly in those without CVD.

Evolving Approaches to Antithrombotics in Stroke Prevention and Treatment

The optimization of antithrombotic therapy for acute stroke treatment and secondary prevention is an evolving process based on an increasing array of studies that provide an evidence-based approach. Options have increased dramatically with the release of the non-vitamin K oral anticoagulants and with the results of recent randomized clinical trials designed to assess potential benefits versus risks for patients in an individualized fashion. Recent studies have provided important information to guide choice and dosing of antiplatelet agents as well as the length of treatment. Anticoagulant use is particularly pertinent for stroke prevention in patients at higher risk of atrial fibrillation and may have a place in certain other stroke mechanisms. One important focus of study is the potential benefit of combined antiplatelet and anticoagulant therapy. Options for our patients, when the initial choice of therapy does not demonstrate benefit or is not well tolerated, clearly, are valuable. For example, short-term dual antiplatelet therapy for minor stroke and transient ischemic attack is being adopted, but with the recognition that longer-term combined therapy is not worth the increased risk of bleeding. Alternative antiplatelet choices, such as cilostazol and possibly ticagrelor, may be of benefit for refractory patients and this could affect the decision-making process. This review represents an effort to incorporate the information from more recent stroke prevention and treatment studies with information gleaned from prior studies.

Long Non-Coding RNA H19 Positively Associates With Aspirin Resistance in the Patients of Cerebral Ischemic Stroke

Background and purpose

Aspirin is a novel anti-platelet drug that is intensively recommended for the prevention and treatment of cerebral ischemic stroke. However, the existence of aspirin resistance weakens the effects of aspirin and usually induces the recurrence of ischemic stroke. While the mechanism underlying aspirin resistance is still unclear. Long non-coding RNA H19 (H19) is closely associated with the onset and prognosis of cerebral ischemic stroke. Since the relationship between H19 and aspirin resistance have never been reported, herein, we aimed to evaluate the H19 expression in aspirin-resistant ischemic stroke patients and subsequently, ascertain the ability of H19 to diagnose aspirin resistance.

Methods

We included 150 patients with acute cerebral ischemic stroke who were followed up for one year to determine stroke recurrence. Levels of 11-dehydro thromboxane B2 (11dhTXB2) in urine were tested to evaluate the status of aspirin resistance, and those of H19 and 8-iso-prostaglandin-2α in plasma were assessed. The relationship between 11dhTXB2 or and 8-iso-prostaglandin-2α and H19, and the receiver operating characteristic curve of H19, the association of H19 and aspirin resistance with the recurrence of stoke were statistically analyzed.

Results

Plasma H19 was significantly up-regulated in patients with aspirin resistance (p=0.0203), and the H19 levels were positively associated with urine 11dhTXB2/creatinine (R=0.04364, p=0.0106) and positively associated with the level of 8-iso-PGF2α (R=0.04561, p=0.0089). The ROC curves indicated that H19 can sensitively and specifically diagnose aspirin resistance (area under the curve, 0.8005; 95% CI, 0.7301–0.8710; p < 0.0001; specificity, 75.86207%; sensitivity, 73.84615%.). H19 is an independent risk factor for aspirin resistance (OR=1.129, p=0.0321), and aspirin resistance and H19 are closely related with ischemic stroke recurrence.

Conclusions

H19 is closely associated with aspirin resistance, and H19 probably induces aspirin resistance through increasing the production of 8-iso-prostaglandin-2α. Besides which, H19 may serve as a serological marker for diagnosing aspirin resistance with high specificity and sensitivity, and the test of H19 could give clues to the recurrence of ischemic stroke.

Association of aspirin resistance with 4-hydroxynonenal and its impact on recurrent cerebral infarction in patients with acute cerebral infarction

OBJECTIVES

To investigate the association of aspirin resistance (AR) with the plasma 4-hydroxynonenal (4-HNE) level and its impact on recurrent cerebral infarction (CI) in patients with acute cerebral infarction (ACI) who were receiving aspirin therapy.

METHODS

One hundred and fifty-four ACI patients who previously received aspirin therapy (100 mg/day) were enrolled. Whole urine (for measuring 11dhTXB2 and creatinine) along with blood (for measuring the plasma 4-HNE level) were collected at least 7 days after the patients received aspirin. A cutoff of 1500 pg/mg of 11dhTXB2/ creatinine was used to determine AR. A follow-up period to monitor recurrence CI events was 1 year. In addition, blood testing was performed when the patients were first admitted to hospital.

RESULTS

Forty-six of the 154 enrolled patients (29.9%) were found to be AR. No statistical difference in age, sex, hypertension, diabetes mellitus, coronary disease, smoking status, NIHSS score, TOAST classification, platelet count, thrombocytocrit, LDL-C, HDL-C, TG, and TC was found between the AR and aspirin-sensitive (AS) patients, but the plasma 4-HNE level was found to be higher in the AR patients than AS patients (p < .05). Multiple logistic regression analysis showed that the 4-HNE level was associated with a higher risk of AR (OR = 1.034; 95% CI = 1.011-1.058; p < .05). Moreover, 1-year follow-up showed that AR was more prevalent in patients with recurrent CI (26 (56.6%)) than those without (20/(43.5%)) (p < .001).

CONCLUSIONS

The plasma 4-HNE level is strongly associated with AR and thus may be a factor contributing to AR. Patients with AR have a greater risk of recurrence CI.

Study of the Association of V640L (rs6133) Polymorphism in the Platelet P-selectin Gene with Acetylsalicylic Acid Resistance in Patients after Coronary Bypass Surgery

Aim.To study the association of V640L (rs6133) polymorphism in the P-selectin gene with acetylsalicylic acid (ASA) resistance in patients with coronary heart disease after coronary bypass surgery (CABG).Material and methods.The study included 104 patients aged 36-78 years (mean age 61.6±6.9 years) with stable angina pectoris: 61 (58.7%) patients had functional class II (according to Canadian Cardiovascular Society), 41 (39.4%) – class III and 2 (1.9%) – class IV. Atherosclerotic lesions of the coronary arteries were confirmed by coronary angiography. The antiplatelet therapy was stopped for at least 5 days before CABG. In the postoperative period, from the first day, all patients received 100 mg of ASA in enteric form, 61 patients received alone ASA therapy, 43 patients – combined antiplatelet therapy: ASA+clopidogrel (75 mg/day). The aggregation study was performed with an optical aggregometer, using 5 μM adenosinediphosphate (ADP) and 1 mM arachidonic acid inductors before CABG, on 1-3 day and on 8-10 day after surgical treatment. DNA samples were examined for the V640L (rs6133) polymorphism in the P-selectin gene by real-time polymerase chain reaction (PCR) using the allele-specific primers.

Results. The frequency of the homozygous GG genotype of the rs6133 polymorphism was 84.6%; heterozygous GT genotype – 15.4%. The amplitude of aggregation with ADP before CABG, on 1-3 day and on 8-10 day after CABG for carriers of homozygotes of allele G vs carriers of the allele T were: 47.9±19.3%, 44.5±17.8%, 30.1±13.2% vs 47.9±17.1%, 46.3±16.5%, 39.6±22.0%, respectively (p=0.497, 0.441 and 0.687, respectively). The amplitude of aggregation with arachidonic acid before CABG, on 1-3 day and on 8-10 day after CABG for carriers of homozygotesof allele G vs carriers of the allele T, were: 47.9±23.2%, 24.5±21.7%, 12.3±16.3% vs 54.3±17.8%, 29.7±23.7%,  11±10.9%, respectively (p=0.416, 0.825 and 0.872, respectively). In the first 10 days of the postoperative period, 6 thrombotic events (5.7%) were observed in the study group: 2 strokes and 4 perioperative myocardial infarctions. Five events occurred in the group of patients with the GG genotype, 1 event in the group of patients with the GT genotype.Conclusion. V640L (rs6133) polymorphism in the P-selectin gene is not associated with ASA resistance in patients with coronary artery disease after CABG. The T allele of the rs6133 polymorphism is not associated with increased platelet aggregation activity after CABG and does not increase the risk of adverse events in the first 10 days after CABG.

Aspirin resistance mediated by oxidative stress-induced 8-Isoprostaglandin F2

WHAT IS KNOWN AND OBJECTIVE

Aspirin resistance refers to a patient's poor response to aspirin. There are many factors that can contribute to aspirin resistance, including single-nucleotide polymorphisms, medication compliance, drug-drug interactions and inflammation.

COMMENT

Recently, oxidative stress-induced 8-isoprostaglandin F2α has attracted considerable attention because it is considered as a mechanism of aspirin resistance in many diseases, including coronary artery disease, neurology system disease, metabolic syndrome, cancer, chronic obstructive pulmonary disease and chronic kidney disease. In these diseases, increased oxidative stress may promote platelet activation and reduce the efficacy of aspirin by producing excessive amounts of 8-isoprostaglandin F2α.

WHAT IS NEW AND CONCLUSION

Given the wide clinical use of aspirin, it is essential to understand why some patients do not response to it. This article reviews current research on aspirin resistance mediated by oxidative stress-induced 8-isoprostaglandin F2α.

Significance of urinary 11-dehydro-thromboxane B2 in age-related diseases: Focus on atherothrombosis

Platelet activation plays a key role in atherogenesis and atherothrombosis. Biochemical evidence of increased platelet activation in vivo can be reliably obtained through non-invasive measurement of thromboxane metabolite (TXM) excretion. Persistent biosynthesis of TXA₂ has been associated with several ageing-related diseases, including acute and chronic cardio-cerebrovascular diseases and cardiovascular risk factors, such as cigarette smoking, type 1 and type 2 diabetes mellitus, obesity, hypercholesterolemia, hyperhomocysteinemia, hypertension, chronic kidney disease, chronic inflammatory diseases. Given the systemic nature of TX excretion, involving predominantly platelet but also extraplatelet sources, urinary TXM may reflect either platelet cyclooxygenase-1 (COX-1)-dependent TX generation or COX-2-dependent biosynthesis by inflammatory cells and/or platelets, or a combination of the two, especially in clinical settings characterized by low-grade inflammation or enhanced platelet turnover. Although urinary 11-dehydro-TXB₂ levels are largely suppressed with low-dose aspirin, incomplete TXM suppression by aspirin predicts the future risk of vascular events and death in high-risk patients and may identify individuals who might benefit from treatments that more effectively block in vivo TX production or activity. Several disease-modifying agents, including lifestyle intervention, antidiabetic drugs and antiplatelet agents besides aspirin have been shown to reduce TX biosynthesis. Taken together, these aspects may contribute to the development of promising mechanism-based therapeutic strategies to reduce the progression of atherothrombosis. We intended to critically review current knowledge on both the pathophysiological significance of urinary TXM excretion in clinical settings related to ageing and atherothrombosis, as well as its prognostic value as a biomarker of vascular events.

Prognostic value of urinary 11-dehydro-thromboxane B2 for mortality: A cohort study of stable coronary artery disease patients treated with aspirin

AIM

There is a variable cardiovascular risk reduction attributable to aspirin because of individual differences in the suppression of thromboxane A₂ and its downstream metabolite 11-dehydro-thromboxane B₂ (11dhTxB₂ ). The aim of this study is to evaluate the optimal cut point of urinary 11dhTxB₂ for the risk of mortality in aspirin-treated coronary artery disease (CAD) patients.

METHODS AND RESULTS

This was a prospective cohort study including stable CAD patients who visited the Baylor Heart and Vascular Hospital in Dallas or the Texas Heart Hospital Baylor Plano, TX between 2010 and 2013. The outcome of all-cause mortality was ascertained from chart review and automated sources. The 449 patients included in this analysis had a mean age of 66.1 ± 10.1 years. 67 (14.9%) patients died within 5 years; 56 (87.5%) of the 64 patients with known cause of death suffered a cardiovascular related mortality. Baseline ln(urinary 11dhTxB₂ /creatinine) ranged between 5.8 and 11.1 (median = 7.2) with the higher concentrations among those who died (median: 7.6) than those who survived (median = 7.2, P < 0.001). Using baseline ln(11dhTxB₂ ) to predict all-cause mortality, the area under the curve was 0.70 (95% CI: 0.64-0.76). The optimal cut point was found to be ln(7.38) = 1597.8 pg/mg, which had the following decision statistics: sensitivity = 0.67, specificity = 0.62, positive predictive value = 0.24, negative predictive value = 0.92, and accuracy = 0.63.

CONCLUSION

Our data indicate the optimal cut point for urine 11dhTxB2 is 1597.8 (pg/mg) for the risk prediction of mortality over five years in stable patients with CAD patients treated with aspirin.

Influence of smoking and smoking cessation on levels of urinary 11-dehydro thromboxane B2

Background

Thromboxane is a key clinical risk endpoint of smoking-induced inflammation which has been associated in the pathogenesis of cardiovascular disease. The goal of this review is to quantify the effect of smoking and smoking cessation on one of its urinary metabolites, 11-dehydrothromboxane_B2.

Methods

PubMed and SCOPUS were searched to identify publications which report urinary 11-dehydrothromboxane_B2 levels in smokers and non-smokers, as well as articles reporting the effect of smoking cessation on urinary 11-dehydrothromboxane_B2 excretion.

Results

We found ten studies assessing urinary 11-dehydrothroboxane_B2 levels in smokers and non-smokers. Four papers reported the amount of urinary 11-dehydrothromboxane_B2 excreted in 24 h while six reported the amount excreted adjusted for creatinine. The meta-analyses comparing the excretion of urinary 11-dehydrothromboxane in current smokers to non-smokers report increased levels in current smokers (mean difference = 0.31 μg/24-h [95%CI: 0.27-0.34] and 166.45 pg/mg creatinine [95%CI: 120.51-212.40]). There were not enough publications to perform meta-analyses on the effects of smoking cessation on urinary 11-dehydrothromboxane_B2 excretion.

Conclusions

Urinary 11-dehydrothromboxane_B2 levels are increased in cigarette smokers, however, more data are needed to elucidate the effects of smoking cessation on urinary 11-dehydrothromboxane_B2 excretion.

Relationship of peripheral and coronary artery disease to cardiovascular events in patients with atrial fibrillation

BACKGROUND

To investigate the impact of concomitant asymptomatic peripheral artery disease (PAD) and pre-existing coronary artery disease (CAD) on cardiovascular events (CVEs) in atrial fibrillation (AF) patients.

METHODS

Prospective multicenter study including 1138 anticoagulated AF patients. PAD was diagnosed by can ankle-brachial index (ABI)≤0.9, and CAD as a documented myocardial infarction (MI) or cardiac revascularization. The cohort was divided into 4 groups: group 0 (n=717) with no previous CAD and ABI >0.9; group 1 (n=168) no previous CAD and ABI≤0.9; group 2 (n=183) previous CAD and ABI >0.9: and group 3 (n=70) previous CAD and ABI≤0.9. The primary endpoint was a composite of CVEs.

RESULTS

Mean age was 72.6years and 41.3% were female. History of CAD was present in 253 (22.2%) patients, and 238 (20.9%) had an ABI≤0.9. Patients with previous CAD were more likely to have a low ABI compared to those without (OR:1.6, 95%CI 1.2-2.3, P=0.003). Median follow-up was 35.9months (IQR 19.2-57.2, 3819 patient-years), and 145 CVEs were recorded (3.8%/year 95%CI 3.2-4.5). Survival analysis showed a progressive increase in the rate of CVEs in the four groups (log-rank test P<0.001). Multivariable Cox regression analysis showed that as compared to group 0, group 1 (HR:1.8, 95%CI 1.1-2.9, P=0.01), group 2 (HR:2.2, 95%CI 1.4-3.4, P=0.001) and group 3 (HR:2.4, 95%CI 1.4-4.4, P=0.003) were associated with progressive greater risk of CVEs.

CONCLUSION

Patients with concomitant CAD and asymptomatic PAD are at high risk of CVEs, with a progressive risk with vascular disease burden where PAD was associated with CAD.

Differential Impact of Serial Measurement of Nonplatelet Thromboxane Generation on Long-Term Outcome After Cardiac Surgery

BACKGROUND

Systemic thromboxane generation, not suppressible by standard aspirin therapy and likely arising from nonplatelet sources, increases the risk of atherothrombosis and death in patients with cardiovascular disease. In the RIGOR (Reduction in Graft Occlusion Rates) study, greater nonplatelet thromboxane generation occurred early compared with late after coronary artery bypass graft surgery, although only the latter correlated with graft failure. We hypothesize that a similar differential association exists between nonplatelet thromboxane generation and long-term clinical outcome.

METHODS AND RESULTS

Five-year outcome data were analyzed for 290 RIGOR subjects taking aspirin with suppressed platelet thromboxane generation. Multivariable modeling was performed to define the relative predictive value of the urine thromboxane metabolite, 11-dehydrothromboxane B₂ (11-dhTXB₂), measured 3 days versus 6 months after surgery on the composite end point of death, myocardial infarction, revascularization or stroke, and death alone. 11-dhTXB₂ measured 3 days after surgery did not independently predict outcome, whereas 11-dhTXB₂ >450 pg/mg creatinine measured 6 months after surgery predicted the composite end point (adjusted hazard ratio, 1.79; P=0.02) and death (adjusted hazard ratio, 2.90; P=0.01) at 5 years compared with lower values. Additional modeling revealed 11-dhTXB₂ measured early after surgery associated with several markers of inflammation, in contrast to 11-dhTXB₂ measured 6 months later, which highly associated with oxidative stress.

CONCLUSIONS

Long-term nonplatelet thromboxane generation after coronary artery bypass graft surgery is a novel risk factor for 5-year adverse outcome, including death. In contrast, nonplatelet thromboxane generation in the early postoperative period appears to be driven predominantly by inflammation and did not independently predict long-term clinical outcome.