Clinical Background    
A 73-year-old man with a history of diabetes, hypertension, peripheral arterial disease, and dementia underwent autopsy following cardiac death. He had received three biodegradable polymer sirolimus-eluting stents (BP-SES; Ultimaster, Terumo) seven years earlier for chronic coronary syndrome. His case offers a rare window into the histopathological state of third-generation BP-SES long after implantation—contributing critical knowledge about late-stage neoatherosclerosis.

Presentation and Decline    
Two years before his death, the patient discontinued his cardiac medications. He presented with acute chest pain, and labs showed poorly managed risk factors—hemoglobin A1c of 11.6% and LDL/Non-HDL cholesterol of 108/123 mg/dL. ECG revealed ST elevations in V2–V6, and cardiac enzymes were elevated (CPK 889 IU/L, troponin T 3.2 ng/ml), confirming acute myocardial infarction. He declined invasive care and passed away the next day.

Histological Findings    
Autopsy revealed an acute anteroseptal myocardial infarction. Importantly, none of the stented arteries exhibited in-stent thrombosis or restenosis. The right coronary artery showed full endothelialization over a moderately calcified plaque, indicating stable healing. The left anterior descending artery demonstrated signs of neoatherosclerosis—small calcifying necrotic cores atop a fibrous plaque—while the left circumflex artery revealed superficial foamy macrophages without necrosis, both over calcified, stable plaques.

Implications of Neoatherosclerosis    
Neoatherosclerosis was present in two of the three stents. Although indicative of late-stage changes, the findings were relatively benign: no necrotic core rupture, no thrombus formation, and moderate underlying plaque calcification. This suggests a lower risk of very late stent thrombosis (VLST), a concern with earlier-generation stents. The BP-SES appeared to support a more stable long-term vascular healing process, even in a high-risk patient.'