Severe multivessel coronary artery spasm presenting as very high-risk acute coronary syndrome.

Coronary artery spasm is an important cause of myocardial ischaemia and acute coronary syndrome in the absence of obstructive coronary artery disease. Simultaneous multivessel epicardial coronary artery spasm is an uncommon presentation and may closely mimic severe three-vessel coronary artery disease. We report a man in his early 60s presenting with acute coronary syndrome associated with profound hypoxaemia and systemic prodromal symptoms. Coronary angiography demonstrated severe, diffuse smooth narrowing of all three major epicardial coronary arteries with critically impaired flow, initially suggestive of advanced multivessel disease. Intracoronary nitrate administration resulted in rapid and near-complete resolution of the coronary narrowing with restoration of normal flow. Optical coherence tomography showed only mild non-obstructive atheroma without plaque rupture or thrombus, confirming multivessel coronary artery spasm. The patient developed a small spasm-related myocardial infarction and recovered well following optimisation of vasodilator therapy.