Relation of aspirin response to age in patients with stable coronary artery disease

A Systematic Review on the Effect of Common Medications on Platelet Count and Function: Which Medications Should Be Stopped Before Getting a Platelet-Rich Plasma Injection?

Background:

Platelet-rich plasma (PRP) exerts its effect through the release of growth factors and cytokines from the platelet concentrate. Certain medications may affect platelet count or function, resulting in decreased efficacy of PRP injections.

Purpose:

To systematically review the literature regarding common medications and their effects on platelets to establish guidelines for which medications should be stopped before obtaining a PRP injection.

Study Design:

Systematic review; Level of evidence, 2.

Methods:

This review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A search for studies assessing the effect of common medications on platelet count or platelet function was performed of the PubMed, Cochrane Library, Web of Science, and OpenGrey databases. Inclusion criteria were as follows: drug studied was aspirin, acetaminophen, a nonsteroidal anti-inflammatory drug (NSAID), a statin, or gabapentin; human participants; and article in the English language. Risk of bias was assessed using the Cochrane Risk of Bias tool and the Risk of Bias in Non-randomised Studies—of Interventions tool.

Results:

A total of 1711 studies were identified through the initial search, with 20 studies meeting all inclusion criteria. No studies involving gabapentin met all inclusion criteria. Patients treated with aspirin (268 patients) or acetaminophen (13 patients) showed a significant decrease in platelet aggregation. Statin therapy (73 patients) did not result in a significant decrease in platelet aggregation. Patients who took NSAIDs (172 patients) demonstrated significantly decreased platelet aggregation only when treated with nonselective formulations. Those treated with cyclooxygenase (COX)-2–selective NSAIDs showed no significant difference in platelet aggregation. Treatment with aspirin, acetaminophen, statins, or NSAIDs did not lead to a significant decrease in platelet count.

Conclusion:

Aspirin, acetaminophen, and nonselective NSAIDs should be considered for suspension before a PRP injection because of their potential to diminish the effects of the injection. COX-2–selective NSAIDs and statins do not need to be withheld before a PRP injection.

[Chronic ischaemic heart disease in the elderly]

It is the aim of this manuscript to take into account the peculiarities and specific characteristics of elderly patients with chronic ischaemic heart disease from a multidisciplinary perspective, with the participation of the Spanish Society of Cardiology (sections of Geriatric Cardiology and Ischaemic Heart Disease/Acute Cardiovascular Care), the Spanish Society of Internal Medicine, the Spanish Society of Primary Care Physicians and the Spanish Society of Geriatrics and Gerontology. This consensus document shows that in order to adequately address these elderly patients a comprehensive assessment is needed, which includes comorbidity, frailty, functional status, polypharmacy and drug interactions. We conclude that in most patients medical treatment is the best option and that this treatment must take into account the above factors and the biological changes associated with aging.

Comparison of platelet inhibition by prasugrel versus ticagrelor over time in patients with acute myocardial infarction

High on-treatment platelet reactivity (HTPR) despite use of P2Y12 antagonists is associated with adverse cardiac events. The long-term variability in response to prasugrel and ticagrelor is unclear. Our aim was to assess residual platelet reactivity (PR) and rates of HTPR during treatment with prasugrel versus ticagrelor in patients with myocardial infarction (MI). 114 patients with MI treated with percutaneous coronary intervention (PCI) were included. Sixty-two patients were treated with prasugrel (mean age 58 ± 8 years, 21 % women, 29 % diabetes), and 52 patients with ticagrelor (mean age 63 ± 9, 19 % women, 37 % diabetes). Patients were tested for PR at 2-4 days and 30 days post-PCI, using the VerifyNow P2Y12 assay and the multiple-electrode aggregometry. Our results show a higher residual PR in patients treated with prasugrel than those treated with ticagrelor (VerifyNow: 65.4 ± 60.6 vs. 26.0 ± 24.2 P2Y12 reaction units, p < 0.001 at 2-4 days, and 67.3 ± 62.5 vs. 21.1 ± 26.1, p < 0.001 at follow-up). HTPR rates were higher in the prasugrel group (8.1-11.3 % vs. none with ticagrelor in the early test, and 8.7-10.9 % vs. none with ticagrelor at follow-up). In conclusion, in patients with MI undergoing PCI, treatment with ticagrelor resulted in greater platelet inhibition and lower HTPR rates compared with prasugrel, up to 30 days after the event.

Clopidogrel response variability is associated with endothelial dysfunction in coronary artery disease patients receiving dual antiplatelet therapy

OBJECTIVES

Dual antiplatelet therapy with aspirin and a platelet P2Y12 ADP receptor antagonist is the cornerstone of treatment following percutaneous coronary intervention (PCI). Several clinical and genetic factors can cause suboptimal clopidogrel response. We examined the impact of endothelial dysfunction on clopidogrel response variability in subjects with stable coronary artery disease (CAD) after PCI.

METHODS

We consecutively enrolled 198 patients with stable CAD one month after successful PCI. All patients were receiving dual antiplatelet therapy (clopidogrel 75 mg and aspirin 100 mg/day). Platelet reactivity was measured by VerifyNow P2Y12 assay (Accumetrics, San Diego, CA). VerifyNow reports its results in P2Y12 reaction units (PRU) and the diagnostic cut-off value is 230. Endothelial function was evaluated by flow mediated dilation (FMD).

RESULTS

Patients with high on treatment platelet reactivity (32% of the study population), compared to subjects with low on treatment platelet reactivity, presented decreased FMD values (4.35 ± 2.22% vs. 5.74 ± 3.29%, p = 0.01). Moreover, an inverse association between endothelial function measurement and platelet reactivity (r = -0.24, p = 0.001) was found. Importantly, multivariate analysis after adjustment for age, gender and confounders revealed by the univariate analysis (left ventricle ejection fraction, body mass index, diabetes, dyslipidemia, coronary lesion number) showed that for every decrease in FMD by 1% there is an anticipated increased in the odds of patients to have HPR by 1.66 (95% CI 1.03-2.57, p = 0.037).

CONCLUSIONS

Endothelial dysfunction is associated with clopidogrel response variability in patients after PCI receiving dual antiplatelet therapy. These findings shed some light on the mechanisms affecting individual platelet response to antiplatelet therapy and may explain the non-straight forward association between clopidogrel dose, platelet inhibition and cardiovascular outcome.

Evaluation of S100B in the diagnosis of suspected intracranial hemorrhage after minor head injury in patients who are receiving platelet aggregation inhibitors and in patients 65 years of age and older

OBJECT

Cranial CT (CCT) scans and hospital admission are increasingly performed to rule out intracranial hemorrhage in patients after minor head injury (MHI), particularly in older patients and in those receiving antiplatelet therapy. This leads to high radiation exposure and a growing financial burden. The aim of this study was to determine whether the astroglial-derived protein S100B that is released into blood can be used as a reliable negative predictive tool for intracranial bleeding in patients after MHI, when they are older than 65 years or being treated with antiplatelet drugs (low-dose aspirin, clopidogrel).

METHODS

The authors conducted a prospective observational study in 2 trauma hospitals. A total of 782 patients with MHI (Glasgow Coma Scale Score 13-15) who were on medication with platelet aggregation inhibitors (PAIs) or were age 65 years and older, independent of antiplatelet therapy, were included. Clinical examination, bloodwork, observation, and CCT were performed in the traumatology emergency departments. When necessary, patients were admitted and observation took place on the ward; in these patients, CCT was performed during their hospital stay. Patients with severe trauma, focal neurological deficits, posttraumatic seizures, anticoagulant therapy, alcohol intoxication, coagulation disorder, blood sampling more than 3 hours after trauma, and unknown time of the trauma were excluded from the study. The median age of the patients was 83 years, and 69% were female. Sensitivity, specificity, and positive and negative predictive values of S100B with reference to CCT findings were calculated. The cutoff of S100B was set at 0.105 μg/L.

RESULTS

Of the 782 patients, 50 (6.4%) had intracranial bleeding. One patient with positive results on CCT scan showed an S100B level below 0.105 μg/L. Of all patients, 33.1% were below the cutoff. S100B showed a sensitivity of 98.0% (CI 89.5%-99.7%), a negative predictive value of 99.6% (CI 97.9%-99.9%), a specificity of 35.3% (CI 31.9%- 38.8%), and a positive predictive value of 9.4% (CI 7.2%-12.2%).

CONCLUSIONS

Levels of S100B below 0.105 μg/L can accurately predict normal CCT findings after MHI in older patients and in those treated with PAIs. Combining conventional decision criteria with measurement of S100B can reduce the CCT scan and hospital admission rates by approximately 30%.

Determinants of reduced antiplatelet effect of aspirin in patients with stable coronary artery disease

Background

Aspirin is a cornerstone in management of coronary artery disease (CAD). However, considerable variability in the antiplatelet effect of aspirin has been reported.

Aim

To investigate independent determinants of reduced antiplatelet effect of aspirin in stable CAD patients.

Methods

We performed a cross-sectional study including 900 stable, high-risk CAD patients. Among these, 795 (88%) had prior myocardial infarction, 250 (28%) had type 2 diabetes, and 170 (19%) had both. All patients received 75 mg aspirin daily as mono antiplatelet therapy. The antiplatelet effect of aspirin was assessed by measurement of platelet aggregation employing 1) multiple electrode aggregometry (MEA, Multiplate Analyzer) in whole blood anticoagulated with citrate or hirudin using arachidonic acid (AA) or collagen as agonists, and 2) VerifyNow Aspirin Assay. Compliance was assessed by measurement of serum thromboxane B₂.

Results

Platelet count, prior myocardial infarction, type 2 diabetes and body mass index were independent determinants of increased AA-induced MEA platelet aggregation in citrate and hirudin anticoagulated blood (p-values ≤ 0.045). Similar results were found with VerifyNow. Prior coronary artery bypass grafting, age, smoking (MEA, AA/citrate) and female gender (MEA, AA/hirudin) were also independent determinants of increased platelet aggregation (p-values ≤ 0.038). Compliance was confirmed by low serum thromboxane B₂ levels in all patients (median [25%;75%]: 0.97 [0.52;1.97], range 0.02-26.44 ng/ml).

Conclusion

Platelet count, prior myocardial infarction, type 2 diabetes and body mass index were independent determinants of increased platelet aggregation, indicating that these characteristics may be key factors in reduced antiplatelet effect of aspirin in stable CAD patients.