Does high serum uric acid level cause aspirin resistance?

Factors Associated with Aspirin Resistance in Hong Kong Chinese Patients with Stable Coronary Heart Disease Using the Multiplate® Analyzer and Serum Thromboxane B2

Introduction: Aspirin resistance may be associated with various conditions. We measured serum thromboxane B2 (TXB2) and platelet function using the Multiplate® Analyzer with arachidonic acid (ASPI) in patients on long term aspirin therapy to identify aspirin resistance and associated factors. Materials and Methods: Chinese patients with stable coronary heart disease had samples for serum TXB2 and ASPI measurement taken before and 1 h after taking a morning dose of 80 mg aspirin. Results: In 266 patients with mean age 66.6 ± 10.7 years, 17% were female and 55% were current or previous smokers. TXB2 and ASPI measurements were significantly higher before the dose than at 1 h post dose, with 46% of subjects having high ASPI values (AUC > 300 AU*min) pre dose compared with 27% at 1 h post dose. TXB2 and ASPI measures of platelet aggregation showed weak correlations, which were only significant before the dose (r = 0.219, p = 0.001). Increased ASPI measurements were associated with white blood cell (WBC) count, haematocrit, platelet count and heart rate at 24 h post dose but only with WBC count, smoking history and heart rate at 1 h post dose. Diabetes was not associated with reduced platelet response to aspirin. The WBC count associated with aspirin resistance was over 6.55 × 109/L by receiver operating characteristic analysis. Conclusions: The antiplatelet response to aspirin was reduced in a large proportion of patients. Patients with higher WBC count within the normal range appear to be at increased risk of aspirin resistance. Higher or more frequent doses of aspirin may be needed in many patients.

The Prognostic Value of Serum Uric Acid in Hospitalized Patients with Acute Cerebral Infarction

Background

Previous studies reported that the level of serum uric acid (SUA) was an important risk factor for acute cerebral infarction (ACI). However, the prognostic value of SUA levels in hospitalized patients with ACI has not been fully elucidated. The aim of this study was to investigate whether the SUA level on admission was associated with subsequent mortality in hospitalized patients with ACI.

Methods

The clinical data of ACI patients obtained from December 2017 to December 2019 were retrospectively reviewed. χ² and Kaplan–Meier methods were used to compare the clinical differences and overall survival between patients with or without hyperuricemia, respectively. Univariate and multivariate analyses were used to identify independent prognoses.

Results

In the total population, the in-hospital mortality of the hyperuricemia group was significantly higher than that of the normal uric acid group (P = 0.006). In the abnormal renal function group, the in-hospital mortality among the hyperuricemia group was significantly higher than the normal uric acid group (P = 0.002). However, there was no statistical difference of in-hospital mortality between the two groups in the normal renal function group (P = 0.321). Univariate and multivariate analyses showed that a previous history of diabetes (P = 0.018), hyperuricemia (P = 0.001), and National Institutes of Health Stroke Scale (NIHSS) score on admission (P ≤ 0.001) were independent factors for all samples. The hyperuricemia (P = 0.003) on admission were independent factors for patients with abnormal renal function.

Conclusions

In ACI patients with abnormal renal function, hyperuricemia may be associated with higher in-hospital mortality than patients with normal uric acid, and hyperuricemia may be an independent associated factor for in-hospital death in the subgroup patients.

Platelet Surface CD62p and Serum Vitamin D Levels are Associated with Clopidogrel Resistance in Chinese Patients with Ischemic Stroke

BACKGROUND

To explore the association of platelet activation markers, vitamin D, and antiplatelet drugs resistance in ischemic stroke patients.

METHODS

A total of 230 patients with ischemic stroke were enrolled in this study. Platelet aggregation, platelet activation marker (CD62p), and vitamin D were measured after 7-14 days of dual antiplatelet treatment (aspirin + clopidogrel). All individuals were divided into a drug resistance group and a drug sensitive group according to the platelet maximum aggregation rate induced by antagonist adenosine diphosphate or arachidonic acid.

RESULTS

In this study, the prevalence of aspirin resistance was low (1.2%), while the prevalence of clopidogrel resistance (CR) was 24.8%, so we focused on CR. The percentage of CD62p on activated platelet [(25.74 ± 4.61) versus (12.41 ± 3.93), P < .001] and the prevalence of hypertension [93.0% (53) versus 79.8% (138), P = .021] in CR group were significantly higher than those in clopidogrel sensitive (CS) group, while the vitamin D concentration [(8.96 ± 4.41) versus (13.9 ± 4.84) ng/mL, P = .003] in CR group was significantly lower compared with the CS group. No significant difference was found in soluble P-selectin between these 2 groups [(56.2 ± 16.13) versus (54.2 ± 14.87) ng/mL, P = .258], neither in calcium [(2.29 ± .12) versus (2.33 ± .13) mmol/L, P = .821]. Logistic regression analysis showed that hypertension (odds ratio [OR] = 5.348, 95% confidence intervals [CI] 1.184-23.350, P = .026), expression of platelet CD62p (OR = 1.095, 95% CI 1.052-1.201, P = .018) and vitamin D level (OR = .832, 95% CI .763-.934, P = .005) were associated with CR in ischemic stroke patients.

CONCLUSIONS

CR in ischemic stroke patients is associated with several independent predictors, including increased platelet activation marker CD62p, decreased vitamin D level, and hypertension.

High serum uric acid levels may increase mortality and major adverse cardiovascular events in patients with acute myocardial infarction

Objectives:

To determine the validity of uric acid as a potential prognostic marker for long-term outcomes of patients with acute myocardial infarction (AMI) and those with AMI undergoing percutaneous coronary intervention (PCI).

Methods:

Systematic review and meta-analysis were performed. We retrieved data from retrospective and prospective cohort studies that investigated whether serum uric acid (SUA) level affects the prognosis of patients with AMI.

Results:

Thirteen studies involving 9371 patients were included. High serum uric acid (HSUA) level increased mid/long-term mortality (risk ratio (RR)=2.32, 95% confidence intervals (CI): 2.00–2.70) and had higher short-term mortality (RR=3.09, 95% CI: 2.58–3.71), higher mid/long-term major adverse cardiovascular events (MACE) risk (RR=1.70, 95% CI: 1.54–1.88), and higher short-term MACE risk (RR=2.47, 95% CI: 2.08–2.92) for patients with AMI. In the PCI subgroup, the HSUA level also increased mid/long-term mortality (RR=2.33, 95% CI: 1.89 to 2.87) and had higher mid/long-term MACE risk (RR=1.64, 95% CI: 1.48–1.82), and higher short-term MACE risk (RR 2.43, 95% CI: 2.02–2.93) for patients who were treated with PCI after AMI. Particularly in the PCI subgroup, a higher short-term mortality (RR=6.70, 95% CI: 3.14–14.31) was presented in the group with lower HSUA cut-off level, and the mortality was higher than the group with higher HSUA cut-off level (RR=2.69, 95% CI: 2.09–3.46).

Conclusion:

The HSUA level significantly increased the mortality and MACE risk of patients with AMI. Mild elevation of SUA levels (normal range) have started to have a significant impact on the short-term mortality of patients who underwent PCI, and has not received the attention of previous studies. However, this condition should be further investigated.

Serum Uric Acid, Kidney Function and Acute Ischemic Stroke Outcomes in Elderly Patients: A Single-Cohort, Perspective Study

Chronic kidney disease and hyperuricemia have been associated to an increased risk and a worse prognosis in acute ischemic stroke. Several mechanisms, including platelet dysfunction, coagulation disorders, endothelial dysfunction, inflammation, and an increased risk of atrial fibrillation could be implicated. The role of serum uric acid in this setting is still object of debate. We enrolled all the consecutive patients admitted to our department for acute ischemic stroke. Cox regression analysis was used to evaluate the risk of in-hospital death considering serum uric acid levels and all the comorbidities. In the overall sample, hyperuricemia was independently associated to an increased risk of in-hospital mortality. This effect was stronger in patients with chronic kidney disease while, in the group of patients with normal renal function, the relationship between hyperuricemia and increased stroke mortality was not confirmed. Hyperuricemia could be associated to higher in-hospital mortality for ischemic stroke among elderly patients when affected by kidney disease. Survival does not seem to be affected by hyperuricemia in patients with normal kidney function.