Plaque characterization of a saphenous vein graft by near-infrared spectroscopy and histopathology in a patient with a percutaneous coronary intervention.

Near-infrared spectroscopy (NIRS) is an intravascular imaging (IVUS) modality that detects lipid core plaques in the vessel wall, which are regarded as high-risk plaques for distal embolization in percutaneous coronary interventions (PCI). Saphenous vein graft (SVG) lesions have friable lipid-rich plaques and thrombus prone to distal embolization. The plaque characterization of SVG by NIRS was confirmed herein for the first time with histopathology before and after PCI. The present case was a man in his 60 s with a history of coronary artery bypass graft surgery. Coronary angiography revealed severe stenosis in multiple segments of the SVG to left circumflex artery (LCX). NIRS IVUS showed large amounts of lipidic materials at each segment before PCI. After balloon dilatation, NIRS IVUS revealed a marked reduction in yellow signals on chemography. A histopathological analysis of the captured specimen showed that it was mainly composed of fibrin and contained numerous histiocytes with foam cells, lymphocytes, and other cells, which was consistent with the histopathological findings of plaque rupture.