151. Cardiovascular events occur independently of high on-aspirin platelet reactivity and residual COX-1 activity in stable cardiovascular patients.
- Author
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Nagatsuka K, Miyata S, Kada A, Kawamura A, Nakagawara J, Furui E, Takiuchi S, Taomoto K, Kario K, Uchiyama S, Saito K, Nagao T, Kitagawa K, Hosomi N, Tanaka K, Kaikita K, Katayama Y, Abumiya T, Nakane H, Wada H, Hattori A, Kimura K, Isshiki T, Nishikawa M, Yamawaki T, Yonemoto N, Okada H, Ogawa H, Minematsu K, and Miyata T
- Subjects
- Adult, Aged, Aged, 80 and over, Aspirin adverse effects, Aspirin therapeutic use, Blood Platelets enzymology, Cardiovascular Diseases prevention & control, Cohort Studies, Female, Humans, Male, Middle Aged, Platelet Aggregation Inhibitors adverse effects, Platelet Aggregation Inhibitors therapeutic use, Prospective Studies, Recurrence, Risk Factors, Secondary Prevention, Thromboxane B2 analogs & derivatives, Thromboxane B2 blood, Thromboxane B2 urine, Blood Platelets drug effects, Cardiovascular Diseases blood, Cardiovascular Diseases etiology, Cyclooxygenase 1 blood
- Abstract
Several studies have indicated that approximately 25 % of patients treated with aspirin exhibit high on-treatment platelet reactivity (HTPR), which is potentially associated with cardiovascular events (CVEs). However, this association is still controversial, since the mechanisms by which HTPR contributes to CVEs remain unclear and a no standardised definition of HTPR has been established. To determine whether HTPR is associated with CVE recurrence and what type of assay would best predict CVE recurrence, we conducted a multicentre prospective cohort study of 592 stable cardiovascular outpatients treated with aspirin monotherapy for secondary prevention. Their HTPR was determined by arachidonic acid- or collagen-induced aggregation assays using two different agonist concentrations. Residual cyclooxygenase (COX)-1 activity was assessed by measuring serum thromboxane (TX)B2 or urinary 11-dehydro TXB2. Shear-induced platelet thrombus formation was also examined. We followed all patients for two years to evaluate how these seven indexes were related to the recurrence of CVEs (cerebral infarction, transient ischaemic attack, myocardial infarction, unstable angina, revascularisation, other arterial thrombosis, or cardiovascular death). Of 583 patients eligible for the analysis, CVEs occurred in 69 (11.8 %). A Cox regression model identified several classical risk factors associated with CVEs. However, neither HTPR nor high residual COX-1 activity was significantly associated with CVEs, even by applying cut-off values suggested in previous reports or a receiver-operating characteristic analysis. In conclusion, recurrence of CVEs occurred independently of HTPR and residual COX-1 activity. Thus, our findings do not support the use of platelet or COX-1 functional testing for predicting clinical outcomes in stable cardiovascular patients.
- Published
- 2016
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