A 46 year old female with a non ST segment elevation myocardial infarction (NSTEMI) had a pressure wire assessment to her mid left anterior descending artery (LAD) for an indeterminate lesion. The lesion was physiologically non significant and she was managed medically. She developed further chest pain and subsequently had another coronary angiogram with the use of optical coherence tomography (OCT). This demonstrated a severe mid LAD stenosis and percutaneous coronary intervention (PCI) was performed with a drug eluting stent. In patients with a NSTEMI and angiographically indeterminate coronary lesions the use of OCT should be considered especially if the results of the FFR are questionable.