Comparative Characterization of Biomechanical Behavior and Healing Profile of a Novel Ultra-High-Molecular-Weight Amorphous Poly-l-Lactic Acid Sirolimus-Eluting Bioresorbable Coronary Scaffold.
Clinically available bioresorbable scaffolds (BRS) rely on polymer crystallinity to achieve mechanical strength resulting in limited overexpansion capabilities and structural integrity when exposed to high-loading conditions. We aimed to evaluate the biomechanical behavior and vascular healing profile of a novel, sirolimus-eluting, high-molecular-weight, amorphous poly-l-lactic acid-based BRS (Amaranth BRS).



In vitro biomechanical testing was performed under static and cyclic conditions. A total of 99 devices (65 Amaranth BRS versus 34 Absorb bioresorbable vascular scaffold [BVS]) were implanted in 99 coronary arteries of 37 swine for pharmacokinetics and healing evaluation at various time points. In the Absorb BVS, the number of fractures per scaffold seen on light microscopy was 6.0 (5.0-10.5) when overexpanded 1.0 mm above nominal values (≈34%). No fractures were observed in the Amaranth BRS group at 1.3 mm above nominal values (≈48% overexpansion). The number of fractures was higher in the Absorb BVS on accelerated cycle testing over time (at 24K cycles=5.0 [5.0-9.0] Absorb BVS versus 0.0 [0.0-0.5] Amaranth BRS). Approximately 90% of sirolimus was found to be eluted by 90 days. Optical coherence tomography analysis demonstrated lower percentages of late scaffold recoil in the Amaranth BRS at 3 months (Amaranth BRS=-10±16.1% versus Absorb BVS=10.7±13.2%; P=0.004). Histopathology analysis revealed comparable levels of vascular healing and inflammatory responses between both BRSs up to 6 months.



New-generation high-molecular-weight amorphous poly-l-lactic acid scaffolds have the potential to improve the clinical performance of BRS and provide the ideal platform for the future miniaturization of the technology.
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Yanping
Y
Cheng
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Pawel
P
Gasior
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Masahiko
M
Shibuya
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Kamal
K
Ramzipoor
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Chang
C
Lee
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Edward A
EA
Estrada
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Daniell
D
Dokko
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Jenn C
JC
McGregor
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Gerard B
GB
Conditt
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.).
Greg L
GL
Kaluza
From the CRF-Skirball Center for Innovation, Orangeburg, NY (Y.C., P.G., M.S., J.C.M., G.B.C., G.L.K., J.F.G.); Amaranth Medical, Inc, Mountain View, CA (K.R., C.L., E.A.E., D.D.); and 3rd Department of Cardiology, Medical University of Silesia, Katowice, Poland (P.G.). jgranada@crf.org.
Juan F
JF
Granada
D020341:Absorbable Implants; D000818:Animals; D001706:Biopsy; D002317:Cardiovascular Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D020099:Coated Materials, Biocompatible; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000473:pathology; D008422:Materials Testing; D023421:Models, Animal; D008970:Molecular Weight; D058426:Neointima; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000295:instrumentation*; D011091:Polyesters / Q000737:chemistry*; D011475:Prosthesis Failure; D020123:Sirolimus / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013552:Swine; D013556:Swine, Miniature; D041623:Tomography, Optical Coherence; D014945:Wound Healing / Q000187:drug effects*
D002317:Cardiovascular Agents; D020099:Coated Materials, Biocompatible; D011091:Polyesters; C033616:poly(lactide); D020123:Sirolimus
lactic acid; molecular weight; optical coherence tomography; polymer; sirolimus