The edge vascular response following implantation of a fully bioresorbable device

The edge vascular response following implantation of the Absorb everolimus-eluting bioresorbable vascular scaffold and the XIENCE V metallic everolimus-eluting stent. First serial follow-up assessment at six months and two years: insights from the first-in-man ABSORB Cohort B and SPIRIT II trials

AIMS

To assess serially the edge vascular response (EVR) of a bioresorbable vascular scaffold (BVS) compared to a metallic everolimus-eluting stent (EES).

METHODS AND RESULTS

Non-serial evaluations of the Absorb BVS at one year have previously demonstrated proximal edge constrictive remodelling and distal edge changes in plaque composition with increase of the percent fibro-fatty (FF) tissue component. The 5 mm proximal and distal segments adjacent to the implanted devices were investigated serially with intravascular ultrasound (IVUS), post procedure, at six months and at two years, from the ABSORB Cohort B1 (n=45) and the SPIRIT II (n=113) trials. Twenty-two proximal and twenty-four distal edge segments were available for analysis in the ABSORB Cohort B1 trial. In the SPIRIT II trial, thirty-three proximal and forty-six distal edge segments were analysed. At the 5-mm proximal edge, the vessels treated with an Absorb BVS from post procedure to two years demonstrated a lumen loss (LL) of 6.68% (-17.33; 2.08) (p=0.027) with a trend toward plaque area increase of 7.55% (-4.68; 27.11) (p=0.06). At the 5-mm distal edge no major changes were evident at either time point. At the 5-mm proximal edge the vessels treated with a XIENCE V EES from post procedure to two years did not show any signs of LL, only plaque area decrease of 6.90% (-17.86; 4.23) (p=0.035). At the distal edge no major changes were evident with regard to either lumen area or vessel remodelling at the same time point.

CONCLUSIONS

The IVUS-based serial evaluation of the EVR up to two years following implantation of a bioresorbable everolimus-eluting scaffold shows a statistically significant proximal edge LL; however, this finding did not seem to have any clinical implications in the serial assessment. The upcoming imaging follow-up of the Absorb BVS at three years is anticipated to provide further information regarding the vessel wall behaviour at the edges.

Scaffold and edge vascular response following implantation of everolimus-eluting bioresorbable vascular scaffold: a 3-year serial optical coherence tomography study

OBJECTIVES

This study sought to investigate the in-scaffold vascular response (SVR) and edge vascular response (EVR) after implantation of an everolimus-eluting bioresorbable scaffold (BRS) using serial optical coherence tomography (OCT) imaging.

BACKGROUND

Although studies using intravascular ultrasound have evaluated the EVR in metal stents and BRSs, there is a lack of OCT-based SVR and EVR assessment after BRS implantation.

METHODS

In the ABSORB Cohort B (ABSORB Clinical Investigation, Cohort B) study, 23 patients (23 lesions) in Cohort B1 and 17 patients (18 lesions) in Cohort B2 underwent truly serial OCT examinations at 3 different time points (Cohort B1: post-procedure, 6 months, and 2 years; B2: post-procedure, 1 year, and 3 years) after implantation of an 18-mm scaffold. A frame-by-frame OCT analysis was performed at the 5-mm proximal, 5-mm distal edge, and 2-mm in-scaffold margins, whereas the middle 14-mm in-scaffold segment was analyzed at 1-mm intervals.

RESULTS

The in-scaffold mean luminal area significantly decreased from baseline to 6 months or 1 year (7.22 ± 1.24 mm(2) vs. 6.05 ± 1.38 mm(2) and 7.64 ± 1.19 mm(2) vs. 5.72 ± 0.89 mm(2), respectively; both p < 0.01), but remained unchanged from then onward. In Cohort B1, a significant increase in mean luminal area of the distal edge was observed (5.42 ± 1.81 mm(2) vs. 5.58 ± 1.53 mm(2); p < 0.01), whereas the mean luminal area of the proximal edge remained unchanged at 6 months. In Cohort B2, the mean luminal areas of the proximal and distal edges were significantly smaller than post-procedure measurements at 3 years. The mean luminal area loss at both edges was significantly less than the mean luminal area loss of the in-scaffold segment at both 6-month and 2-year follow-up in Cohort B1 or at 1 year and 3 years in Cohort B2.

CONCLUSIONS

This OCT-based serial EVR and SVR evaluation of the Absorb Bioresorbable Vascular Scaffold (Abbott Vascular, Santa Clara, California) showed less luminal loss at the edges than luminal loss within the scaffold. The luminal reduction of both edges is not a nosologic entity, but an EVR in continuity with the SVR, extending from the in-scaffold margin to both edges. (ABSORB Clinical Investigation, Cohort B [ABSORB B]; NCT00856856).