The Impact of Aspirin Resistance on the Long‐term Cardiovascular Mortality in Patients with Non‐ST Segment Elevation Acute Coronary Syndromes

BACKGROUND: Aspirin resistance has been associated with an adverse long-term outcome in patients with atherosclerotic coronary artery disease, but more studies are needed. HYPOTHESIS: The aim of this study was to investigate the impact of aspirin resistance, assessed by the Platelet Function Analyzer-100 (PFA-100) (Dade Behring Inc., Deerfield, Ill., USA) on the long-term prognosis in patients with non-ST segment elevation acute coronary syndromes (NSTE-ACS). METHODS: A total of 496 consecutive patients were studied. The 1-y incidence of cardiovascular death was the prespecified study endpoint. The patients were divided, according to the values of PFA-100 collagen epinephrine closure time (CEPI-CT) upon presentation, into aspirin sensitives (those with a PFA-100 CEPI-CT>193 sec) and aspirin resistants (those with a PFA-100 CEPI-CT<or=193 sec). RESULTS: Aspirin resistants were younger (p-value = 0.04), and less frequently hypertensives (p-value=0.05) or diabetics (p-value=0.04) than aspirin sensitives. By 1 y, the incidence of cardiovascular deaths in the entire cohort was 12.9% (64/496), and aspirin resistants were at significantly higher risk of cardiovascular death (23.1% versus 9.6%; hazard ratio [HR]=2.6; 95% confidence interval [CI]=1.6-4.3; p-value<0.001), than aspirin sensitives. By multivariate Cox regression analysis, aspirin resistance (a PFA-100 CEPI-CT<or=193 sec) was among the most potent predictors of the 1-y incidence of cardiovascular death (HR=2.8; 95% CI=1.7-4.6; p-value<0.001). CONCLUSION: According to the present data, aspirin resistance, assessed by the PFA-100, is an independent predictor of long-term cardiovascular mortality in patients with NSTE-ACS.