Suboptimal stent deployment is associated with subacute stent thrombosis: optical coherence tomography insights from a multicenter matched study. From the CLI Foundation investigators: the CLI-THRO study.

BACKGROUND Acute or subacute stent thrombosis (ST) is a well-described complication usually causing acute coronary syndromes and, in the worst case scenario, sudden cardiac death. In this study, we aimed at exploring the potential role of optical coherence tomography (OCT) in the understanding of the mechanism of ST. METHODS Twenty-one consecutive patients, after acute coronary syndromes due to a definite subacute ST, were assessed with OCT and matched 1:2 with 42 patients undergoing OCT for scheduled follow-up. Optical coherence tomography assessment was focused on features indicative of nonoptimal stent deployment: underexpansion, malapposition, edge dissection, and reference lumen narrowing. RESULTS Optical coherence tomography revealed a minimum stent area sensibly smaller in the ST group (5.6 ± 2.6 vs 6.8 ± 1.7 mm(2); P = .03) with a higher incidence of stent underexpansion when compared with the control group (42.8% vs 16.7%; P = .05). Dissection at stent edges was more commonly detected in ST group (52.4% vs 9.5%; P < .01). No significant differences between the 2 groups were observed for malapposition (52.4% vs 38.1%; P = .651) and reference lumen narrowing (19.0% vs 4.8%; P = .172). At least 1 OCT finding indicative of suboptimal stent deployment was detectable in 95.2% of patients experiencing ST versus 42.9% of the control group (P < .01). CONCLUSIONS Optical coherence tomography assessment in patients experiencing subacute ST revealed nonoptimal stent deployment in almost all cases with higher incidence of stent underexpansion and edge dissection, potentially explaining the cause of this adverse event. The adoption of an OCT-guided percutaneous coronary intervention protocol could have a potential for the prevention of ST in complex cases.