Aims: Our aim was to describe the intravascular ultrasound (IVUS) findings of patients with late stent thrombosis (ST) undergoing percutaneous intervention, and to compare the pre- and post-intervention IVUS findings of patients treated with balloon angioplasty (BA) vs. additional stent implantation (ASI).
Methods and results: A total of 117 patients with late ST imaged with IVUS were included (51.2% had drug-eluting stent ST). Treatment was left to the operator's discretion: BA was performed in 53.8% and ASI in 46.2%. Pre-intervention, incomplete stent apposition (ISA) was observed in 69.8% vs. 63.0% (p=0.43), underexpansion in 33.3% vs. 18.5% (p=0.07) and restenosis in 15.9% vs. 27.8% (p=0.12), respectively. Post-intervention, persistent ISA was observed in 37.2% vs. 60.9% (p=0.03) and malapposition volume decreased by 43.6% vs. 2.6% (p=0.03). Persistent underexpansion was observed in 9.3% vs. 17.4% (p=0.26); however, the stent expansion index was largely increased with BA (from 0.75 to 0.88) compared to ASI (from 0.80 to 0.82); p=0.046. At two years, recurrent ST was observed in one (1.7%) vs. four (7.7%) patients, respectively; p=0.09.
Conclusions: Non-optimal IVUS criteria of stent implantation are often observed in patients with late ST. Treatment of late ST with BA leads to a larger reduction of malapposition and underexpansion with respect to ASI and is associated with favourable outcomes.