Prevalence and patterns of in-stent neoatherosclerosis in lower extremity artery disease

Background: In-stent restenosis (ISR) is responsible for a rapid decline of vessel patency after stenting. To date, little is known about the role of in-stent neoatherosclerosis (NA) in stent failure in lower limb arteries.

Aims: This study aimed to determine the prevalence and patterns of in-stent NA in patients with symptomatic ISR of the lower extremity vasculature using intravascular optical coherence tomography (OCT) imaging.

Methods: Patients underwent endovascular revascularisation for ISR including angiography and OCT imaging. NA was defined as the presence of at least 1 fibroatheroma or fibrocalcific plaque within the neointima of a stented segment.

Results: Using OCT, we imaged 24 symptomatic patients with lower extremity artery disease (LEAD), with a total of 30 ISR in the lower limbs, prior to their scheduled endovascular interventions. NA formation was observed in 23 (76.7%) lesions, while all stents with an implant duration >5 years (n=8) showed signs of NA. The time from stent implantation to OCT was significantly increased in lesions with NA (p=0.002). Lesions without NA had a significantly shorter duration from index procedure to OCT than those with ≥50 percent (n=9; p=0.003) or <50 percent (n=14; p=0.015) of frames exhibiting signs of NA. NA was predominantly characterised by fibroatheroma with thick fibrous caps with or without calcification.

Conclusions: In-stent NA is frequently identified by OCT imaging after endovascular therapy in lower limb arteries; this increased both in frequency and extent the longer the duration since implantation. Our findings indicate an active atherosclerotic process that may need tailored mitigation strategies.