Characteristic Virtual Histology- Intravascular Ultrasound Imaging of Immunoglobulin G4-Related Coronary Artery Disease Patient

A 60-year-old male was admitted to the hospital with chest pain. Electrocardiogram, and transthoracic echocardiography revealed no abnormalities. Serum immunoglobulin G (IgG) was 855 mg/dL (700-1,700), erythrocyte sedimentation rate 11 mm/hour (0-9), and antinuclear antibodies were negative. Cardiac enzymes, and C-reactive protein were within the normal range. Coronary computed tomography (CT) angiography showed masses surrounding the proximal, distal left anterior descending artery (LAD) (Figure 1A), mid and distal right coronary artery (RCA) (Figure 1B). Coronary angiography showed proximal, distal LAD (Figure 1C), mid RCA, and distal RCA stenosis (Figure 1D). Intravascular ultrasound (IVUS) of the LAD showed low-or iso-echoic lesions involving the intima, media, and adventitia. Referring to the results of virtual histology (VH)-IVUS, these LAD lesions consisted of fibrotic plaques (Figure 1E). The mid RCA lesion showed a pattern of onion peel shape in the media layer (yellow arrow) extending into the adventitia (red arrow). In VH-IVUS analysis, most of them were fibrotic plaques, but necrotic lesions were included in a small amount (Figure 1F). The proximal LAD and mid RCA lesions were treated with drug-eluting stents. We diagnosed the patient with an IgG4-related disease (IgG4-RD) and treated the patients with Deflazacort (Calcort) 12 mg. Five months later, follow-up coronary CT revealed improved soft tissue thickening and enhancement at distal LAD (Figure 1G) and distal RCA (Figure 1H). Several IVUS imaging studies of IgG4-RD coronary periarteritis demonstrated thickening of the adventitia, or overall perivascular thickening.1) IgG4-RD can extensively invade the intima, media, and adventitia.2) Also, our case was the only case showing VH-IVUS of IgG4-RD, and lesions consisted of fibrous tissue.Written informed consent was obtained from the patient.