The purpose of the present study was to investigate the association between left ventricular systolic function and the response to clopidogrel. The efficacy of clopidogrel was measured by the vasodilator-stimulated phosphoprotein phosphorylation 20 +/- A 4 h after 600 mg of clopidogrel.
High on-clopidogrel platelet reactivity (HCPR) was defined as a platelet reactivity index (PRI) a parts per thousand yen50 %. The 30-day combined incidence of death, non-fatal acute coronary syndrome, re-percutaneous coronary intervention (PCI), stent thrombosis, and stroke was also investigated.
The study group consisted of 519 patients undergoing PCI. The values (mean and 95 % confidence interval) of the PRI were as follows: 40.4 % (37.8-43.0) in patients with left ventricular ejection fraction (LVEF) > 50 %, 42.4 % (39.3-45.6) in patients with LVEF 35-50 %, and 46.7 % (40.6-52.9) in patients with LVEF < 35 % (p = 0.013).
The proportions of patients with HCPR were 35.9 % in patients with LVEF a parts per thousand yen35 and 51.9 % in patients with LVEF < 35 % (p = 0.022). After adjustment for variables that significantly influenced clopidogrel efficacy, LVEF < 35 % was found to be independently associated with HCPR (p = 0.039).
The 30-day combined clinical endpoint occurred in 18 % of patients with LVEF < 35 % and in 7.3 % of patients with LVEF a parts per thousand yen35 % (p = 0.026). The 30-day incidence of all-cause mortality was 14 % in patients with LVEF < 35 and 1.0 % in patients with LVEF a parts per thousand yen35 % (p < 0.001).
An LVEF < 35 % was found to be independently associated with HCPR.