Natural consequence of post-intervention stent malapposition, thrombus, tissue prolapse, and dissection assessed by optical coherence tomography at mid-term follow-up

AIMS: We performed this study to clarify natural consequences of abnormal structures (stent malapposition, thrombus, tissue prolapse, and stent edge dissection) after percutaneous coronary intervention (PCI). METHODS AND RESULTS: Thirty-five patients treated with 40 drug-eluting stents underwent serial optical coherence tomography (OCT) imaging immediately after PCI and at the 8-month follow-up. Among a total of 73 929 struts in every frame, 431 struts (26 stents) showed malapposition immediately after PCI. Among these, 49 remained malapposed at the follow-up examination. The mean distance between the strut and vessel wall (S–V distance) of persistent malapposed struts on post-stenting OCT images was significantly longer than that of resolved malapposed struts (342 ± 99 vs. 210 ± 49 μm; P <0.01). Based on receiver-operating characteristic curve analysis, an S–V distance ≤260 µm on post-stenting OCT images was the corresponding cut-off point for resolved malapposed struts (sensitivity: 89.3%, specificity: 83.7%, area under the curve = 0.884). Additionally, 108 newly appearing malapposed struts were observed on follow-up OCT, probably due to thrombus dissolution or plaque regression. Thrombus was observed in 15 stents post-PCI. Serial OCT analysis revealed persistent thrombus in 1 stent, resolved thrombus in 14 stents, and late-acquired thrombus in 8 stents. Tissue prolapse observed in 38 stents had disappeared at the follow-up. All eight stent edge dissections were repaired at the follow-up. CONCLUSION: Most cases of stent malapposition with a short S–V distance, thrombus, tissue prolapse, or minor stent edge dissection improved during the follow-up. These OCT-detected minor abnormalities may not require additional treatment.