Background: Previous studies were suggestive of a good prognosis in patients with acute coronary syndrome (ACS) and absence of any critical stenosis in coronary angiography but recent limited reports have revealed that patients with non-obstructive acute coronary syndrome are at a higher risk of future clinical coronary events.

Methods : A concurrent prospective cohort study was designed and 146 male patients with ACS and non-obstructive coronary artery disease were regarded as the unexposed group, while 191 female patients with non-obstructive coronary artery disease were regarded as the exposed group. Coronary events were recorded within one year of follow-up. Prognostic factors were evaluated at baseline by using a standardized protocol.
Results : Of the 337 patients with ACS, 191 (56.6%) were female. Coronary events in female patients after one year of follow-up were: ST EMI 3 (1.6%), unstable angina pectoris 22 (11.5%), Q-wave MI 1 (0.5%) and no syncope. In male patients the outcomes were: ST EMI 4 (2.7%), unstable angina pectoris 29 (19.9%), Q-wave MI 1 (0.7%), and syncope 1 (0.7%). Multivariate adjusted relationships revealed that physical inactivity (P=0.035), dyslipidemia (P=0.001), low ankle brachial index (P=0.024) and age between 40-50 years (P=0.004) were significantly associated with coronary events in women. In male patients, body mass index of 30-39.99 (P=0.011) was associated with a higher rate of ST-segment elevated MI.
Conclusion: Prognostically, coronary events and clinical endpoints were significantly different between men and women with acute coronary syndrome. Persistence of symptoms over one year seems to relate to the development and progression of coronary atherosclerosis.