The prevalence, risk factors and prognosis of aspirin resistance in elderly male patients with cardiovascular disease
The Aging Male, 08/15/2012
Cao J et al. – Aspirin resistance or semiresponders, defined by light transmission aggregometry (LTA), are associated with an increased risk of adverse clinical events in elderly male patients with cardiovascular disease (CVD).Methods
- Authros enrolled 304 elderly male patients with CVD receiving daily aspirin therapy (≥ 75 mg) more than 1 month.
- Platelet aggregation was measured by light transmission aggregometry (LTA) and thrombelastography platelet mapping assay (TEG).
- The median follow–up time was 1.8 years.
- The primary outcome was the composite of death, myocardial infarction, unstable angina, stroke and transient ischemic attack.
- By LTA, 25 (8.2%) of elderly patients were aspirin resistant and 106 (34.9%) patients were semiresponders.
- According to TEG, 62 patients (20.4%) were found to be resistant to aspirin therapy.
- Of the 62 patients with aspirin resistance by TEG, 21 patients were aspirin resistant by LTA.
- Twenty–two of the 106 semiresponders by LTA were aspirin resistant by TEG.
- Patients with aspirin resistance or aspirin semiresponders were at increased risk of the composite outcome compared with aspirin–sensitive patients by LTA (18.3% vs 9.8%, Hazard ratio (HR) = 1.864, 95% confidence interval (CI): 1.046–3.324 p = 0.039).
- However, aspirin resistance was not associated with an increased risk of clinical vascular events compared to aspirin–sensitive patients by TEG (17.7% vs 10.9%, p = 0.452).
- In addition, Cox proportional hazard regression modeling demonstrated that aspirin resistance or semiresponders (HR = 3.050, 95% CI: 1.464–6.354, p = 0.003) and diabetes (HR = 2.055, 95% CI: 1.060–3.981, p = 0.033) were associated with major adverse long–term outcomes.