Optical coherence tomography versus intravascular ultrasound for culprit lesion assessment in patients with acute myocardial infarction

INTRODUCTION: In patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI) the implanted stent may not fully cover the whole intravascular ultrasound (IVUS)-derived thin-cap fibroatheroma (TCFA) related to the culprit lesion (CL). AIM: Whether this phenomenon is more pronounced when optical coherence tomography (OCT) assessment of the CL is performed is not known. MATERIAL AND METHODS: Thus, we aimed to assess CLs in 40 patients with AMI treated with PCI, using VH (virtual histology)-IVUS and OCT before and after intervention. The results were blinded to the operator and PCI was done under angiography guidance. RESULTS: Uncovered lipid-rich plaques were identified in the stent reference segments of 23 (57.5%) patients: in 13 (32.5%) of them in the distal reference segment and in 19 (47.5%) of them in the proximal reference segment. In 9 of them (22.5%) lipid plaques were found in both reference segments. In 36 (90%) patients OCT confirmed lipid plaques identified as VH-derived TCFA by VH-IVUS in the reference segments of the stented segment. However, OCT confirmed that only in 2 (5%) patients were uncovered lipid plaques true TCFA as defined by histology. Comparing IVUS and OCT qualitative characteristics of the stented segments OCT detected more thrombus protrusions and proximal and distal stent edge dissections compared to IVUS (92.5 vs. 55%, p = 0.001; 20% vs. 7.5%, p = 0.03 and 25% vs. 5%, p < 0.001, respectively). CONCLUSIONS: Due to its superior resolution, OCT identifies TCFA more precisely. OCT more often shows remaining problems related to stent implantation than IVUS after angiographically guided PCI.