Objective This prospective study sought to assess the diagnostic value of optical coherence tomography (OCT) compared with intravascular ultrasound (IVUS) in patients presenting with stent thrombosis (ST).

Design and setting Although the role of IVUS in this setting has been described, the potential diagnostic value of OCT in patients suffering ST remains poorly defined. Catheterization Laboratory, University Hospital.

Patients and interventions Fifteen consecutive patients with ST undergoing rescue coronary interventions under combined IVUS/OCT imaging guidance were analysed.

Mean outcome measures Analysis and comparison of OCT and IVUS findings before and after interventions.

Results Before intervention, OCT visualised the responsible thrombus in all patients (thrombus area 4.7±2.5 mm², stent obstruction 82±14%). Minimal stent area was 4.7±2.1 mm² leading to severe stent underexpansion (expansion 60±21%). Although red or mixed thrombus (14 patients) induced partial strut shadowing (total length 12.3±6 mm), malapposition (six patients), inflow-outflow disease (five patients), uncovered struts (nine patients) and associated in-stent restenosis (five patients, four showing neoatherogenesis) was clearly recognised. IVUS disclosed similar findings but achieved poorer visualisation of thrombus–lumen interface and strut malapposition, and failed to recognise uncovered struts and associated neoatherosclerosis. After interventions, OCT demonstrated a reduced thrombus burden (2.4±1.6 mm²) and stent obstruction (24±14%) with improvements in stent area (6.8±2.9 mm²) and expansion (75±21%) (all p<0.05). IVUS and OCT findings proved to be complementary.

Conclusions OCT provides unique insights on the underlying substrate of ST and may be used to optimise results in these challenging interventions. In this setting, OCT and IVUS have complementary diagnostic values.