Severe acute stent malapposition follow-up: 3-month and 12-month serial quantitative analyses by optical coherence tomography

Optical coherence tomography (OCT) was used to assess serial changes in severe acute stent malapposition (ASM) after drug-eluting stent (DES) implantation.The maximal depth and axial lengths of ASM after DES implantation were serially quantified at percutaneous coronary intervention (PCI), and at 3 and 12-month follow-up, for 100 lesions in 96 patients. Severe ASM was defined as a maximal malapposed depth ≥400 μm or maximal malapposed axial length ≥1 mm.Of the 100 lesions, 23 lesions (23%) had a severe ASM depth at PCI. At 3 months, the maximal depth decreased to400 μm in 12 of 23 lesions (52%). At 12 months, the maximal depth further decreased to400 μm in 8 of the remaining 11 lesions (73%). Similarly, of 53 lesions (53%) with a severe ASM length at PCI, the maximal length decreased to 0 mm in 26 (49%) but remained severe in 17 lesions (32%) at 3 months. At 12 months, 9 of the 17 remaining lesions (53%) further decreased to 0 mm. The cut-off values for the maximal malapposed depth and length to predict the absence of stent malapposition at 12 months were 565 μm at PCI and 165 μm at 3 months, and were 2.7 mm at PCI and 0.1 mm at 3 months, respectively.Half of the severe ASM cases resolved within 3 months, and another half resolved during 3-12 months of follow-up. Our findings provide a better understanding of the time-dependent natural course of severe ASM using OCT.