Clinical efficacy of aspirin with identification of intimal morphology by optical coherence tomography in preventing event recurrence in patients with vasospasm-induced acute coronary syndrome.

Using optical coherence tomography (OCT), we found that there were morphological differences in the coronary intima between patients with vasospasm-induced acute coronary syndrome (VACS) and those with stable variant angina. We investigated whether aspirin use would protect against chest pain recurrence in patients with VACS. A retrospective cohort study was performed. Patients with ST-segment elevation who were confirmed to have VACS by a provocation test were included. OCT was performed at the index event and when chest pain recurred to assess intimal morphology. Chest pain recurrence was defined as the first revisit to the emergency room with angina. Propensity score matching was performed between the aspirin and non-aspirin groups. For 48 months, 154 patients were followed (77 patients in each group). The baseline characteristics and OCT findings were well balanced between the two groups after propensity score matching. Myocardial infarction (17 vs. 3%, p = 0.003) and chest pain recurrence (26 vs. 9%, p = 0.006) occurred more frequently in the non-aspirin group than in the aspirin group. Multiple Cox regression analysis showed that aspirin use was a significant predictor of lower risk of myocardial infarction [hazard ratio (HR) 0.13; 95% confidence interval (CI) 0.03-0.61] and chest pain recurrence (HR 0.33; 95% CI 0.12-0.71) during the follow-up period, after adjustments for relevant covariates including OCT findings. The use of aspirin may have a preventive effect on myocardial infarction and chest pain recurrence in patients with VACS. Randomized controlled trials are necessary to confirm the result.