Helwani MA, et al. - In this retrospective cohort study, the etiology of perioperative acute coronary syndrome was investigated focusing on thrombosis vs demand ischemia. Researchers examined adult patients who underwent coronary angiography for acute coronary syndrome within 30 days of noncardiac surgery at a major tertiary hospital between January 2008 and July 2015. They found that demand ischemia was the dominant mechanism of perioperative acute coronary syndrome in this cohort. No evidence of obstructive coronary artery disease was found in a subset of patients, but findings were consistent with stress-induced cardiomyopathy.