Long-term invasive follow-up of bioresorbable vascular scaffold: Optical Coherence Tomography assessment of jailed side branches

Background: Little is known about the long term development of the tissue bridges covering the struts of bioresorbable vascular scaffold (BVS) at the side branches (SB) ostium. This study aims at assessing the resorption process of jailed SB after BVS implantation.
Methods: We performed both Optical Coherence Tomography (OCT) and Intravascular Ultrasound (IVUS) analysis of 7 patients enrolled in the ABSORB Cohort B trial at our center. Orifice SB area and mean thickness of tissue bridge covering SB were calculated from 2D assessment. The number of SB orifice compartments separated by BRS struts was analysed by using 3D OCT reconstruction.
Results: At 5 years follow-up, no struts could be identified. Between 3 and 5 years, both lesion-level and cross section-level OCT findings showed a significant increase in Mean lumen area (MLA) as well as Minimum Lumen Area (MinLA). Moreover, eccentricity index showed a significant reduction between 3 and 5years. We identified a total of 3 SBs ostia in the segments treated with BVS. Between 3 and 5 years follow-up in all SB analysed, we detected a decrease of mean tissue bridge thickness and an increase of calculated SBs area.
Conclusions: In our serial OCT, a significant decrease of tissue bridge formation together with SB orifice area enlargement from 3 to 5. year follow-up has been proved.