Bioresorption and Vessel Wall Integration of a Fully Bioresorbable Polymeric Everolimus-Eluting Scaffold: Optical Coherence Tomography, Intravascular Ultrasound, and Histological Study in a Porcine Model With 4-Year Follow-Up.
OBJECTIVE
The aim of the present study was to investigate the relationship between the integration process and luminal enlargement with the support of light intensity (LI) analysis on optical coherence tomography (OCT), echogenicity analysis on intravascular ultrasound, and histology up to 4 years in a porcine model.


BACKGROUND
In pre-clinical and clinical studies, late luminal enlargement has been demonstrated at long-term follow-up after everolimus-eluting poly-l-lactic acid coronary scaffold implantation. However, the time relationship and the mechanistic association with the integration process are still unclear.


METHODS
Seventy-three nonatherosclerotic swine that received 112 Absorb scaffolds were evaluated in vivo by OCT, intravascular ultrasound, and post-mortem histomorphometry at 3, 6, 12, 18, 24, 30, 36, 42, and 48 months.


RESULTS
The normalized LI, which is the signal densitometry on OCT of a polymeric strut core normalized by the vicinal neointima, was able to differentiate the degree of connective tissue infiltration inside the strut cores. Luminal enlargement was a biphasic process at 6 to 18 months and at 30 to 42 months. The latter phase occurred with vessel wall thinning and coincided with the advance integration process demonstrated by the steep change in normalized LI (0.26 [interquartile range (IQR): 0.20 to 0.32] at 30 months versus 0.68 [IQR: 0.58 to 0.83] at 42 months, p < 0.001).


CONCLUSIONS
In this pre-clinical model, late luminal enlargement relates to strut integration into the arterial wall. Quantitative LI analysis on OCT could be used as a surrogate method for monitoring the integration process of poly-l-lactic acid scaffolds, which could provide insight and understanding on the imaging-related characteristics of the bioresorption process of polylactide scaffolds in human.
ThoraxCenter, Erasmus Medical Center, Rotterdam, the Netherlands.
Shimpei
S
Nakatani
ThoraxCenter, Erasmus Medical Center, Rotterdam, the Netherlands.
Yuki
Y
Ishibashi
Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
Yohei
Y
Sotomi
Abbott Vascular, Santa Clara, California.
Laura
L
Perkins
Leiden University Medical Center, Leiden, the Netherlands.
Jeroen
J
Eggermont
Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
Maik J
MJ
Grundeken
Leiden University Medical Center, Leiden, the Netherlands.
Jouke
J
Dijkstra
Abbott Vascular, Santa Clara, California.
Richard
R
Rapoza
CVPath Institute, Gaithersburg, Maryland.
Renu
R
Virmani
International Centre for Circulatory Health, National Heart and Lung Institute, Imperial College London, London, United Kingdom.
Patrick W
PW
Serruys
ThoraxCenter, Erasmus Medical Center, Rotterdam, the Netherlands. Electronic address: yoshinobuonuma@gmail.com.
Yoshinobu
Y
Onuma
D020341:Absorbable Implants; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000295:instrumentation*; D000818:Animals; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D020099:Coated Materials, Biocompatible; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000473:pathology; D000068338:Everolimus / Q000008:administration & dosage*; D023421:Models, Animal; D011091:Polyesters / Q000737:chemistry*; D011237:Predictive Value of Tests; D034421:Sus scrofa; D013552:Swine; D013556:Swine, Miniature; D013997:Time Factors; D041623:Tomography, Optical Coherence; D018084:Ultrasonography, Interventional
D002317:Cardiovascular Agents; D020099:Coated Materials, Biocompatible; D011091:Polyesters; C033616:poly(lactide); D000068338:Everolimus
biodegradable polymer; bioresorbable scaffold; coronary intervention; intravascular ultrasound; optical coherence tomography; pathology