Calcified neoatherosclerosis causing in-stent restenosis: prevalence, predictors, and implications

Neoatherosclerosis has emerged as a major cause of in-stent restenosis (ISR). Although this entity has been described as a unique process, optical coherence tomography (OCT) enables depiction of distinct morphologic patterns, including the presence of calcified sheets within the stent. We sought to assess prevalence, predictors, and implications of calcified neoatherosclerosis (cNA) as the cause of ISR.

From January 2014 to August 2016, 75 consecutive patients with 81 ISR lesions with a clinical indication for revascularization were evaluated by OCT before reintervention. In 13 (16%) lesions, cNA was the predominant pattern of ISR, all of them presenting as very-late (>3 years) ISR. Patients with cNA were older (71±9 vs. 66±10 years, P=0.0157), had worse low-density lipoprotein control (97±29 vs. 81±30 mg/dl, P=0.0746), and received treatment with statins (54 vs. 85%, P=0.006) and angiotensin-converting-enzyme inhibitors/angiotensin receptor blockers (ACEi/ARB) (31 vs. 65%, P=0.003) less frequently compared with patients with other patterns of ISR. Time from stent implantation to ISR [odds ratio (OR)=1.3; 95% confidence interval (CI): 1.1-1.6; P=0.01] and absence of treatment with statins (OR=11.3; 95% CI: 1.7-74; P=0.012) or ACEi/ARB (OR=7.4; 95% CI: 1.3-43; P=0.026) were associated independently with the presence of cNA. During reinterventions, ISR lesions with cNA obtained poorer angiographic (postintervention minimal lumen diameter 1.8±0.4 vs. 2.2±0.5 mm, P=0.0174) and OCT (final stent expansion 83±11 vs. 88±9%, P=0.0896) results.

In our cohort of consecutive patients with clinical ISR, one-sixth showed underlying cNA as the predominant substrate of restenosis. This unique underlying substrate is related to the time elapsed from stent implantation and the absence of previous treatment with statins or ACEi/ARB and is associated with poorer acute results after reintervention.