Prevalence and outcomes of stent thrombosis with in-stent calcified nodules: substudy from the REAL-ST registry.

Background: The relationship between in-stent calcified nodules (IS-CN) and second-generation drug-eluting stent (G2-DES) stent thrombosis (ST) remains uncertain.
Aims: We aimed to evaluate the prevalence, clinical demographic and long-term clinical outcomes after G2-DES ST with IS-CN.
Methods: The prespecified substudy of the REAL-ST registry (a retrospective, multicentre registry of patients with definite ST after first- and G2-DES implantation) enrolled patients who experienced definite G2-DES ST and who underwent pre-intervention intravascular ultrasound imaging at index ST events.
Results: IS-CN was observed in 15 out of 118 (13%) definite G2-DES ST cases. The multiple logistic regression model demonstrated that haemodialysis (odds ratio [OR] 12.27, 95% confidence interval [CI]: 1.56-94.54; p=0.02), proximal or mid-right coronary artery lesions (OR 12.79, 95% CI: 1.78-92.13; p=0.01) and severe calcification (OR 13.01, 95% CI: 1.18-142.94; p=0.04) were independently associated with ST with IS-CN. The cumulative 5-year incidence of target lesion revascularisation (TLR) after ST was significantly higher in the IS-CN group than in the non-IS-CN group (p=0.02). Independent predictors of TLR after the index ST events were female sex (hazard ratio [HR] 3.05, 95% CI: 1.20-7.74; p=0.02), diabetes mellitus (HR 3.26, 95% CI: 1.26-8.41; p=0.01) and IS-CN (HR 3.07, 95% CI: 1.16-8.14; p=0.02).
Conclusions: IS-CN may be one of the underlying mechanisms of G2-DES ST. Notably, IS-CN was associated with a higher TLR rate after the index ST events, suggesting the need for careful clinical follow-up of ST patients with IS-CN.