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The purpose of the present study was to summarize natural consequences of abnormal structures (malapposition, thrombus and dissection) after bioresorbable scaffolds implantation detected by optical coherence tomography (OCT) in healthy swine model at short term follow-up.
Fourty-one pigs (119 vessels) treated with 119 drug bioresorbable scaffolds underwent serial optical coherence tomography (OCT) imaging immediately after implantation and at the 1-day, 7-day, 14-day, 21-day and 28-day follow-up. For each scaffold deployment, an arterial segment was chosen so as to result in a stent-to-artery ratio of 1.1–1.2: 1.
The incidences of acute malapposition in the 119 vessels immediately after implantation and at the every time point were 1.7%, 78.6%, 17.8%, 0%, 0% and 0%. Among a total of 60688 struts in every frame, 122struts (0.2%) showed malapposition immediately after implantation. The incidences of acute struts malapposition were 12.3%, 4.3%, 0%, 0% and 0% at the five time point follow up. There was no thrombus in all the stent malapposition. All the new onset struts malapposition happened immediately after implantation and at the 1-day follow up and resolved spontaneously at the 14-day follow-up. The mean distances between the strut and vessel wall (S–V distance) of malapposed struts immediately after implantation and at the 1-day, 7-day follow-up were 0.04±0.01mm, 0.19±0.03mm, 0.13±0.03mm. Thrombus was observed in 2 vessels (1.7%) at 7-day follow up, 4 vessels (3.3%) at 14-day follow up and 4 vessels (3.3%) at 21-day follow up. They were all resolved at 28-day follow up. Dissections were observed in 6 vessels (5%) immediately after implantation and were repaired at the 14-day follow-up. There was no death case during 28-day follow up.
Acute malapposition had relatively high incidences in 7 days after implantation especially at 1-day follow up. Thrombus and dissections had relatively low incidences. These minor abnormalities detected by optical coherence tomography may not need additional treatment. The Outcome of the minor abnormalities was favorable.